Merge branch 'dev' into uart-debug-event-flash

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: J. Nick Koston <nick@koston.org>
Co-authored-by: J. Nick Koston <nick@home-assistant.io>

.agents/skills/code-review/SKILL.md

@@ -0,0 +1,116 @@
+---
+name: code-review
+description: Review guidance for ESPHome pull requests. Use this when reviewing a pull request that changes ESPHome Python, C++, or component code, to check it against the project's coding conventions, embedded-systems memory rules, testing requirements, and breaking-change policy.
+---
+
+# Reviewing ESPHome pull requests
+
+ESPHome parses YAML into C++ firmware for memory-constrained microcontrollers
+(ESP32, ESP8266, RP2040, LibreTiny). Review changes with that in mind: RAM and
+flash are scarce, and code runs unattended for months.
+
+`AGENTS.md` in the repository root is the full contributor guide and the
+authority when it disagrees with this summary. The developer documentation at
+https://developers.esphome.io explains the component lifecycle and the reasoning
+behind these rules. This skill lists the concrete things worth flagging in a
+review; read `AGENTS.md` for the detail behind any item.
+
+Only raise findings that the diff actually introduces or changes. Do not ask for
+drive-by cleanup of pre-existing code the PR did not touch.
+
+## Memory and embedded constraints (highest value)
+
+Heap allocation after `setup()` is treated as a reliability bug, not a
+performance nit, because it fragments a small shared heap. Flag:
+
+- New heap allocation on a hot path or after setup that could be avoided.
+- `std::vector` where the size is known at compile time (use `std::array`, or
+  `StaticVector<T, N>` when a `push_back` API is needed) or fixed at runtime
+  init (use `FixedVector<T>`).
+- Listener / child-entity registration lists stored as `std::vector`; these have
+  a compile-time-known count and should use `cg.slot_counter()` plus
+  `StaticVector`.
+- `std::vector<uint8_t>` for a byte buffer that never grows: prefer
+  `std::unique_ptr<uint8_t[]>` or `std::array`.
+- `std::map` / `std::set` / `std::unordered_map` for small datasets (1-16
+  elements): a `std::vector` of a small struct with linear search is lighter.
+- `std::deque` anywhere: it allocates 512-byte blocks and should be avoided.
+- `std::string` storing a value set once from config: prefer `StringRef` (the
+  literal already lives in flash).
+- `std::string` / `std::to_string` / string-returning helpers on hot paths where
+  a buffer or view API exists.
+
+## C++ conventions
+
+- Include what you use: a file referencing a symbol must include the header that
+  declares it, even if it currently arrives transitively. New or changed uses of
+  a symbol need the matching include.
+- Prefix all member access with `this->`.
+- Naming: `lower_snake_case` for functions/methods/variables, `UpperCamelCase`
+  for classes/structs/enums, `UPPER_SNAKE_CASE` for namespace-scope constants,
+  trailing underscore on protected/private fields.
+- `enum class` values must be prefixed with the enum name in `UPPER_SNAKE_CASE`
+  (e.g. `UARTFlushResult::UART_FLUSH_RESULT_SUCCESS`). Bare names like `SUCCESS`,
+  `FAIL`, or `OK` collide with SDK macros on some platforms and break the build.
+- Prefer `const`/`enum` over `#define`; `#define` is only for conditional
+  compilation and code-generation sizes.
+- Never call `millis()` in a `loop()` body; use
+  `App.get_loop_component_start_time()`. A rate-limit gate below ~16 ms (the loop
+  period) does nothing.
+- Pick the timing primitive by cadence: gated `loop()` under 250 ms,
+  `set_interval` at 500 ms and above.
+- Do not override a base method to return the value it already returns (e.g.
+  `get_setup_priority()` returning `setup_priority::DATA`).
+- Wrap string literals passed as printf `%s` args in `LOG_STR_LITERAL()`.
+- Required, invariant dependencies should be constructor parameters, not setters.
+- Callback registration methods must be templated (`template<typename F>`), not
+  typed as `std::function`, so lightweight forwarders avoid a heap allocation.
+- Two-space indent, `using` over `typedef`, wrap at 120 columns.
+
+## Python conventions
+
+- Type-annotate every new function signature (params and return), new dataclass
+  fields, and new module-level variables. Import `ConfigType` from
+  `esphome.types`.
+- Use the walrus operator to avoid a double lookup, e.g.
+  `if (blah := config.get(CONF_BLAH)) is not None:`.
+- Reuse existing validators from `config_validation.py` (`cv.rename_key`,
+  `cv.has_exactly_one_key`, etc.) via `cv.All(...)` instead of hand-rolling.
+- `esphome/const.py` is frozen: no new `CONF_` constants there. Define them in
+  the component's own `.py`, or in `esphome/components/const/__init__.py` when
+  shared. The same constant defined in three or more component files fails CI.
+- State that must persist during code generation goes in `CORE.data` namespaced
+  under the component `DOMAIN` (a `@dataclass`), not module-level mutable globals.
+- Prefer callback-based triggers via `build_callback_automation()`; only use a
+  `Trigger<Ts...>` subclass when the forwarder needs mutable state.
+
+## Testing and coverage
+
+- New and changed lines and branches need test coverage, including defensive
+  early-returns, error paths, and no-op guards. A mocked-out function is not
+  covered; exercise the real call path too.
+- Component YAML tests live in `tests/components/<component>/`. Never define
+  buses (uart, i2c, spi, modbus) directly in a test file: pull them from
+  `tests/test_build_components/common/` through dict-style `packages:` so CI can
+  group builds. List-style packages or top-level merge keys block grouping.
+- Config-only checks use the `validate.*.yaml` prefix; compiled checks use
+  `test.*.yaml`.
+
+## Breaking changes and public API
+
+- Base classes under `esphome/core/` and documented config options are public
+  API. Undocumented `public` members of a component are internal.
+- A breaking change needs justification, a migration path in the PR description,
+  and a deprecation window where feasible (`ESPDEPRECATED` in C++,
+  `cv.rename_key(..., removed_in=...)` in Python). Changing a codegen-injected
+  lambda signature is not a breaking change.
+
+## Process and PR hygiene
+
+- PR titles start with a `[tag]` prefix: the component name (e.g. `[uart] ...`)
+  or `[core]` for shared code.
+- Prose in docs, comments, and commit messages should be plain English. Keep
+  inline comments short and only where the code is not self-explanatory; do not
+  restate what the code says.
+- Verify the PR fills out `.github/PULL_REQUEST_TEMPLATE.md` and adds
+  `CODEOWNERS` entries for a new component.

.claude/settings.json

@@ -0,0 +1,16 @@
+{
+  "hooks": {
+    "SessionStart": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "d=\"${CLAUDE_PROJECT_DIR:-.}\"; [ -x \"$d/venv/bin/python\" ] || { mkdir -p \"$d/.temp\"; env -u VIRTUAL_ENV \"$d/script/setup\" >\"$d/.temp/setup.log\" 2>&1 || echo '{\"systemMessage\":\"script/setup failed; see .temp/setup.log\"}'; }",
+            "statusMessage": "Setting up dev environment (script/setup)...",
+            "timeout": 900
+          }
+        ]
+      }
+    ]
+  }
+}

.claude/skills

@@ -0,0 +1 @@
+../.agents/skills

.devcontainer/Dockerfile

@@ -31,7 +31,4 @@ RUN \
     platformio settings set enable_telemetry No \
     && platformio settings set check_platformio_interval 1000000
 
-COPY script/platformio_install_deps.py platformio.ini ./
-RUN ./platformio_install_deps.py platformio.ini --libraries --platforms --tools
-
 WORKDIR /workspaces

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -9,6 +9,29 @@ body:
         If you have a feature request or enhancement, please [request them here instead][fr].
 
         [fr]: https://github.com/orgs/esphome/discussions
+  - type: markdown
+    attributes:
+      value: |
+        ## Use of AI in bug reports
+
+        AI tools are good at carrying out well-defined tasks, but they are not good at troubleshooting.
+        Please do NOT paste an AI-generated wall of text into the issue template - if the AI hasn't solved
+        your problem, its wild guesses are not likely to help.
+
+        Please DO include your own words and observations, compile/boot logs, and
+        especially a minimal reproducible example of your YAML configuration that demonstrates the problem.
+
+        It is however quite acceptable to use AI to translate your *own* report,
+        if you aren't a competent English speaker.
+
+        If you really think it will be useful to include an AI's analysis, preferably wrap it in a `<details>` block which will be collapsed by default.
+
+        If you are using AI to help solve a problem, rather than asking it to speculate about what the problem is,
+        it can be more useful to ask it to create a step-by-step troubleshooting procedure.
+        AI is also useful for generating boilerplate code, such as a minimal reproducible example of your YAML
+        configuration that demonstrates the problem.
+
+        Used properly, AI can be a useful tool to help you solve your problem, but don't let it get in the way.
   - type: textarea
     validations:
       required: true

.github/ISSUE_TEMPLATE/config.yml

@@ -8,7 +8,7 @@ contact_links:
     url: https://github.com/esphome/esphome-webserver/issues/new/choose
     about: Report an issue with the ESPHome web server.
   - name: Report an issue with the ESPHome Builder / Dashboard
-    url: https://github.com/esphome/dashboard/issues/new/choose
+    url: https://github.com/esphome/device-builder/issues/new/choose
     about: Report an issue with the ESPHome Builder / Dashboard.
   - name: Report an issue with the ESPHome API client
     url: https://github.com/esphome/aioesphomeapi/issues/new/choose

.github/PULL_REQUEST_TEMPLATE.md

@@ -6,6 +6,7 @@
 
 - [ ] Bugfix (non-breaking change which fixes an issue)
 - [ ] New feature (non-breaking change which adds functionality)
+- [ ] New developer-facing feature (adds functionality for component developers; no end-user configuration change)
 - [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected) — [policy](https://developers.esphome.io/contributing/code/#what-constitutes-a-c-breaking-change)
 - [ ] Developer breaking change (an API change that could break external components) — [policy](https://developers.esphome.io/contributing/code/#what-is-considered-public-c-api)
 - [ ] Undocumented C++ API change (removal or change of undocumented public methods that lambda users may depend on) — [policy](https://developers.esphome.io/contributing/code/#c-user-expectations)
@@ -20,6 +21,10 @@
 
 - esphome/esphome.io#<esphome.io PR number goes here>
 
+**Pull request in [developers.esphome.io](https://github.com/esphome/developers.esphome.io) with developer documentation (if applicable):**
+
+- esphome/developers.esphome.io#<developers.esphome.io PR number goes here>
+
 ## Test Environment
 
 - [ ] ESP32

.github/actions/build-image/action.yaml

@@ -42,7 +42,7 @@ runs:
 
     - name: Build and push to ghcr by digest
       id: build-ghcr
-      uses: docker/build-push-action@53b7df96c91f9c12dcc8a07bcb9ccacbed38856a # v7.3.0
+      uses: docker/build-push-action@c3c9e263c25d99ce0380d002d59b67737d91b0dc # v7.4.0
       env:
         DOCKER_BUILD_SUMMARY: false
         DOCKER_BUILD_RECORD_UPLOAD: false
@@ -67,7 +67,7 @@ runs:
 
     - name: Build and push to dockerhub by digest
       id: build-dockerhub
-      uses: docker/build-push-action@53b7df96c91f9c12dcc8a07bcb9ccacbed38856a # v7.3.0
+      uses: docker/build-push-action@c3c9e263c25d99ce0380d002d59b67737d91b0dc # v7.4.0
       env:
         DOCKER_BUILD_SUMMARY: false
         DOCKER_BUILD_RECORD_UPLOAD: false

.github/actions/cache-arduino8266/action.yml

@@ -0,0 +1,39 @@
+name: Cache Arduino ESP8266
+description: >
+  Resolve the pinned Arduino core and xtensa toolchain versions and cache the
+  native ESP8266 install (~110 MB framework + toolchain; no ccache store, the
+  seed job saves before any compile runs). Exports
+  ESPHOME_ARDUINO8266_PREFIX to the job so every later step installs into
+  the cached path; the Python venv must already be restored. Mirrors
+  cache-esp-idf: only dev-branch pushes write the shared cache, everything
+  else restores.
+runs:
+  using: composite
+  steps:
+    - name: Resolve the native toolchain cache key
+      # Versions are pinned in code, not a hashable file; resolve them so a
+      # bump changes the cache key. Assignment form so errexit catches a
+      # resolver failure.
+      id: version
+      shell: bash
+      run: |
+        # One owner for the install prefix: exported here and referenced by
+        # the cache steps below via env, so the caller's install and the
+        # cached path cannot diverge.
+        echo "ESPHOME_ARDUINO8266_PREFIX=$HOME/.esphome-arduino8266" >> "$GITHUB_ENV"
+        . venv/bin/activate
+        key=$(python -c 'from esphome.components.esp8266 import RECOMMENDED_ARDUINO_FRAMEWORK_VERSION as f; from esphome.arduino8266.framework import FRAMEWORK_RELEASES, TOOLCHAIN_VERSION as t; print(f"{FRAMEWORK_RELEASES[f].tag}-{t}")')
+        [ -n "$key" ] || exit 1
+        echo "key=$key" >> "$GITHUB_OUTPUT"
+    - name: Cache the native toolchain (write on dev)
+      if: github.ref == 'refs/heads/dev'
+      uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
+      with:
+        path: ${{ env.ESPHOME_ARDUINO8266_PREFIX }}
+        key: ${{ runner.os }}-esp8266-native-${{ steps.version.outputs.key }}
+    - name: Restore the native toolchain (off dev)
+      if: github.ref != 'refs/heads/dev'
+      uses: actions/cache/restore@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
+      with:
+        path: ${{ env.ESPHOME_ARDUINO8266_PREFIX }}
+        key: ${{ runner.os }}-esp8266-native-${{ steps.version.outputs.key }}

.github/actions/cache-clang-tidy-idedata/action.yml

@@ -0,0 +1,50 @@
+name: Cache clang-tidy idedata
+description: >
+  Cache the clang-tidy idedata and the headers it references under .temp
+  (headers only, about 30MB per env). Run after restore-python and cache-esp-idf.
+inputs:
+  environment:
+    description: 'clang-tidy environment (e.g. esp32-idf-tidy).'
+    required: true
+runs:
+  using: composite
+  steps:
+    - name: Compute cache key
+      id: key
+      shell: bash
+      run: |
+        . venv/bin/activate
+        [ -n "${{ inputs.environment }}" ] || { echo "::error::cache-clang-tidy-idedata: 'environment' input is empty"; exit 1; }
+        hash=$(python -c 'import sys; sys.path.insert(0, "script"); from clang_tidy_hash import idedata_cache_hash; print(idedata_cache_hash("${{ inputs.environment }}"))')
+        pyver=$(python -c 'import platform; print(platform.python_version())')
+        # Generating idedata is what installs ESP-IDF; never skip it over a missing
+        # install. This also skips the save, so a dev run that installs ESP-IDF
+        # warms the idedata cache on the next run.
+        if [ -d ~/.esphome-idf/frameworks ]; then
+          echo "skip=false" >> "$GITHUB_OUTPUT"
+        else
+          echo "ESP-IDF install missing, not using the clang-tidy idedata cache"
+          echo "skip=true" >> "$GITHUB_OUTPUT"
+        fi
+        echo "key=${{ runner.os }}-tidy-idedata-${{ inputs.environment }}-$hash-py$pyver" >> "$GITHUB_OUTPUT"
+        {
+          echo "path<<EOF"
+          printf '%s\n' '.temp/idedata-*.json' '.temp/idedata-*.hash'
+          printf '.temp/**/*.%s\n' h hpp hh hxx inc inl ipp tpp
+          echo "EOF"
+        } >> "$GITHUB_OUTPUT"
+    # Mirror cache-esp-idf: write on dev, restore-only on PRs. The post-step
+    # save only runs when the job succeeded, so a failed generation is never saved.
+    # Extend the extension list if a component ships extensionless headers.
+    - name: Cache clang-tidy idedata (write on dev)
+      if: (github.ref == 'refs/heads/dev' || contains(github.event.pull_request.labels.*.name, 'ci-cache-write')) && steps.key.outputs.skip != 'true'
+      uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
+      with:
+        path: ${{ steps.key.outputs.path }}
+        key: ${{ steps.key.outputs.key }}
+    - name: Cache clang-tidy idedata (restore-only off dev)
+      if: github.ref != 'refs/heads/dev' && !contains(github.event.pull_request.labels.*.name, 'ci-cache-write') && steps.key.outputs.skip != 'true'
+      uses: actions/cache/restore@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
+      with:
+        path: ${{ steps.key.outputs.path }}
+        key: ${{ steps.key.outputs.key }}

.github/actions/cache-esp-idf/action.yml

@@ -3,8 +3,10 @@ description: >
   Resolve the pinned ESP-IDF version and cache the native ESP-IDF install
   (toolchains + source) at ~/.esphome-idf. Every job that installs ESP-IDF
   natively (clang-tidy for IDF/Arduino and the component test batches) shares
-  one cache, since the install is identical (ESPHOME_IDF_DEFAULT_TARGETS
-  defaults to "all", so all toolchains are present regardless of the chip).
+  one cache, since the install is identical: ESPHOME_IDF_DEFAULT_TARGETS
+  defaults to "all", and _get_configured_targets() in espidf/toolchain.py
+  skips per-variant narrowing whenever CI is set, so all toolchains are
+  present regardless of the chip a job builds.
   Callers must set env ESPHOME_ESP_IDF_PREFIX: ~/.esphome-idf and have the
   Python venv already restored.
 inputs:
@@ -24,6 +26,9 @@ runs:
       # The native-IDF version is pinned in code, not in any file that feeds the
       # other cache keys, so resolve it explicitly. Keying on it means the cache
       # invalidates on a version bump (actions/cache never overwrites a key).
+      # Also key on the Python version: the cached IDF venv links to the
+      # runner's toolcache interpreter and is reinstalled every run after a
+      # runner image bump.
       id: version
       shell: bash
       run: |
@@ -34,19 +39,32 @@ runs:
           version=$(python -c 'from esphome.components.esp32 import ESP_IDF_FRAMEWORK_VERSION_LOOKUP as L; print(L["recommended"])')
         fi
         echo "version=$version" >> "$GITHUB_OUTPUT"
+        echo "python-version=$(python -c 'import platform; print(platform.python_version())')" >> "$GITHUB_OUTPUT"
     # Mirror the adjacent PlatformIO cache: only dev-branch runs write the
     # shared cache (so it lives in the default-branch scope readable by all
     # PRs), and PRs are restore-only -- they never push multi-GB artifacts into
-    # their own scope / the repo quota (e.g. on a version-bump PR).
+    # their own scope / the repo quota (e.g. on a version-bump PR). The
+    # ci-cache-write label lets a PR write into its own scope to test the hit path;
+    # that costs about 1GB of the repo cache quota per run, so remove it when done.
+    # -slim: bump when prune-esp-idf changes what it removes; a key is never overwritten.
     - name: Cache ESP-IDF install (write on dev)
-      if: github.ref == 'refs/heads/dev' && inputs.restore-only != 'true'
+      if: (github.ref == 'refs/heads/dev' || contains(github.event.pull_request.labels.*.name, 'ci-cache-write')) && inputs.restore-only != 'true'
       uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
       with:
         path: ~/.esphome-idf
-        key: ${{ runner.os }}-esphome-idf-${{ steps.version.outputs.version }}
+        key: ${{ runner.os }}-esphome-idf-${{ steps.version.outputs.version }}-py${{ steps.version.outputs.python-version }}-slim
     - name: Cache ESP-IDF install (restore-only off dev)
-      if: github.ref != 'refs/heads/dev' || inputs.restore-only == 'true'
+      if: github.ref != 'refs/heads/dev' && !contains(github.event.pull_request.labels.*.name, 'ci-cache-write') || inputs.restore-only == 'true'
       uses: actions/cache/restore@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
       with:
         path: ~/.esphome-idf
-        key: ${{ runner.os }}-esphome-idf-${{ steps.version.outputs.version }}
+        key: ${{ runner.os }}-esphome-idf-${{ steps.version.outputs.version }}-py${{ steps.version.outputs.python-version }}-slim
+    # Install explicitly so the prune below sees the toolchains on a cache miss
+    # too, instead of the install happening inside the first build step.
+    - name: Install ESP-IDF
+      shell: bash
+      run: |
+        . venv/bin/activate
+        python -c 'from esphome.espidf.framework import check_esp_idf_install; check_esp_idf_install("${{ steps.version.outputs.version }}")'
+    - name: Prune ESP-IDF install
+      uses: ./.github/actions/prune-esp-idf

.github/actions/prune-esp-idf/action.yml

@@ -0,0 +1,34 @@
+name: Prune ESP-IDF install
+description: >
+  Remove the picolibc sysroots (1.1GB of the 3.9GB install) from the native
+  ESP-IDF toolchains; IDF 5.x links newlib. Skipped when an IDF 6 install is
+  present, which links picolibc (see esp32/__init__.py).
+runs:
+  using: composite
+  steps:
+    - name: Prune picolibc
+      shell: bash
+      run: |
+        shopt -s nullglob
+        prefix="${ESPHOME_ESP_IDF_PREFIX:-$HOME/.esphome-idf}"
+        prefix="${prefix/#\~/$HOME}"
+        for fw in "$prefix"/frameworks/*/; do
+          case "$(basename "$fw")" in
+            [6-9].*) echo "IDF $(basename "$fw") installed, keeping picolibc"; exit 0 ;;
+          esac
+        done
+        n=0
+        for dir in "$prefix"/tools/*-esp-elf/*/*-esp-elf/picolibc; do
+          echo "Removing $dir ($(du -sh "$dir" | cut -f1))"
+          rm -rf "$dir"
+          n=$((n + 1))
+        done
+        # The marker rides along in the cache entry so a restored slim tree stays quiet.
+        if [ "$n" -gt 0 ]; then
+          touch "$prefix/.picolibc-pruned"
+        elif [ -d "$prefix/tools" ] && [ ! -f "$prefix/.picolibc-pruned" ]; then
+          echo "::warning::no picolibc sysroots matched under $prefix/tools"
+        fi
+        if [ -d "$prefix" ]; then
+          du -sh "$prefix"
+        fi

.github/actions/restore-python/action.yml

@@ -17,7 +17,7 @@ runs:
   steps:
     - name: Set up Python ${{ inputs.python-version }}
       id: python
-      uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6.3.0
+      uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
       with:
         python-version: ${{ inputs.python-version }}
     - name: Restore Python virtual environment
@@ -32,7 +32,7 @@ runs:
       # detects the activated venv via ``VIRTUAL_ENV`` so the venv layout
       # downstream jobs rely on is preserved.
       if: steps.cache-venv.outputs.cache-hit != 'true'
-      uses: astral-sh/setup-uv@11f9893b081a58869d3b5fccaea48c9e9e46f990 # v8.3.2
+      uses: astral-sh/setup-uv@c18668ad3cf93ea998bef934396af7bb5c839dc7 # v10.2.0
       with:
         enable-cache: true
         # Pull request saves land in per-PR scopes nothing else can
@@ -49,7 +49,7 @@ runs:
         python -m venv venv
         source venv/bin/activate
         python --version
-        uv pip install -r requirements.txt -r requirements_test.txt
+        uv pip install -r requirements.txt -r requirements_dev.txt -r requirements_test.txt
         uv pip install -e .
     - name: Create Python virtual environment
       if: steps.cache-venv.outputs.cache-hit != 'true' && runner.os == 'Windows'
@@ -58,5 +58,5 @@ runs:
         python -m venv venv
         source ./venv/Scripts/activate
         python --version
-        uv pip install -r requirements.txt -r requirements_test.txt
+        uv pip install -r requirements.txt -r requirements_dev.txt -r requirements_test.txt
         uv pip install -e .

.github/scripts/auto-label-pr/constants.js

@@ -13,6 +13,7 @@ module.exports = {
     'merging-to-release',
     'merging-to-beta',
     'chained-pr',
+    'stacked-pr',
     'core',
     'small-pr',
     'medium-pr',
@@ -22,11 +23,13 @@ module.exports = {
     'has-tests',
     'needs-tests',
     'needs-docs',
+    'needs-developer-docs',
     'needs-codeowners',
     'too-big',
     'labeller-recheck',
     'bugfix',
     'new-feature',
+    'new-feature-developer',
     'breaking-change',
     'developer-breaking-change',
     'undocumented-api-change',
@@ -40,5 +43,17 @@ module.exports = {
     // Keep matching the old esphome-docs name during the transition period
     /https:\/\/github\.com\/esphome\/esphome-docs\/pull\/\d+/,
     /esphome\/esphome-docs#\d+/
+  ],
+
+  DEVELOPER_DOCS_PR_PATTERNS: [
+    /https:\/\/github\.com\/esphome\/developers\.esphome\.io\/pull\/\d+/,
+    /esphome\/developers\.esphome\.io#\d+/
+  ],
+
+  // Files whose developer-facing changes are documented via Python docstrings
+  // only - developers.esphome.io has no reference page for them yet, so PRs
+  // touching nothing but these files (and tests/) skip needs-developer-docs.
+  DEV_DOCS_EXEMPT_FILES: [
+    'esphome/config_validation.py'
   ]
 };

.github/scripts/auto-label-pr/detectors.js

@@ -1,4 +1,4 @@
-const { DOCS_PR_PATTERNS } = require('./constants');
+const { DOCS_PR_PATTERNS, DEVELOPER_DOCS_PR_PATTERNS, DEV_DOCS_EXEMPT_FILES } = require('./constants');
 const {
   COMPONENT_REGEX,
   detectComponents,
@@ -33,16 +33,54 @@ async function fetchPrFileContent(github, context, path) {
   }
 }
 
+// Check whether a pull request is part of a GitHub stack.
+//
+// GitHub's stacked pull request feature adds a `stack` object to the pull
+// request resource. It is present on every pull request in the stack -
+// including the bottom one, whose base is already `dev` - and is absent
+// entirely on standalone pull requests.
+//
+// The `pull_request_target` webhook payload is not guaranteed to carry this
+// field, so fall back to asking the API when it is missing. Guessing wrong
+// here is costly: a stacked pull request mistaken for a manually chained one
+// gets a label that blocks merging.
+async function isStackedPr(github, context) {
+  const pr = context.payload.pull_request;
+  if (pr.stack != null) {
+    return true;
+  }
+
+  try {
+    const { owner, repo } = context.repo;
+    const { data } = await github.rest.pulls.get({
+      owner,
+      repo,
+      pull_number: pr.number,
+    });
+    return data.stack != null;
+  } catch (error) {
+    // Treat an API failure as "not stacked" so a chained pull request still
+    // gets its blocking label rather than silently slipping through.
+    console.log('Failed to check stack membership:', error.message);
+    return false;
+  }
+}
+
 // Strategy: Merge branch detection
-async function detectMergeBranch(context) {
+async function detectMergeBranch(github, context) {
   const labels = new Set();
   const baseRef = context.payload.pull_request.base.ref;
+  const defaultBranch = context.payload.repository.default_branch;
 
   if (baseRef === 'release') {
     labels.add('merging-to-release');
   } else if (baseRef === 'beta') {
     labels.add('merging-to-beta');
-  } else if (baseRef !== 'dev') {
+  } else if (await isStackedPr(github, context)) {
+    // GitHub manages the merge order for a stack, so these are not blocked.
+    labels.add('stacked-pr');
+  } else if (baseRef !== defaultBranch) {
+    // A chain built by hand: it must not merge until its base branch does.
     labels.add('chained-pr');
   }
 
@@ -245,6 +283,7 @@ async function detectPRTemplateCheckboxes(context) {
   const checkboxPatterns = [
     { pattern: /- \[x\] Bugfix \(non-breaking change which fixes an issue\)/i, label: 'bugfix' },
     { pattern: /- \[x\] New feature \(non-breaking change which adds functionality\)/i, label: 'new-feature' },
+    { pattern: /- \[x\] New developer-facing feature \(adds functionality for component developers; no end-user configuration change\)/i, label: 'new-feature-developer' },
     { pattern: /- \[x\] Breaking change \(fix or feature that would cause existing functionality to not work as expected\)/i, label: 'breaking-change' },
     { pattern: /- \[x\] Developer breaking change \(an API change that could break external components\)/i, label: 'developer-breaking-change' },
     { pattern: /- \[x\] Undocumented C\+\+ API change \(removal or change of undocumented public methods that lambda users may depend on\)/i, label: 'undocumented-api-change' },
@@ -355,12 +394,14 @@ async function detectRequirements(allLabels, prFiles, context, hasYamlLoadable)
   const labels = new Set();
 
   // Check for missing tests
-  if ((allLabels.has('new-component') || allLabels.has('new-platform') || allLabels.has('new-feature')) && !allLabels.has('has-tests')) {
+  if ((allLabels.has('new-component') || allLabels.has('new-platform') || allLabels.has('new-feature') || allLabels.has('new-feature-developer')) && !allLabels.has('has-tests')) {
     labels.add('needs-tests');
   }
 
   // Check for missing docs.
-  // `new-feature` (PR-body checkbox) always counts. `new-component` / `new-platform`
+  // `new-feature` (PR-body checkbox) always counts. `new-feature-developer` is
+  // deliberately excluded here: its docs live on developers.esphome.io and are
+  // checked separately below. `new-component` / `new-platform`
   // only count when at least one newly added file defines a top-level CONFIG_SCHEMA,
   // i.e. the new component/platform is actually loadable from YAML.
   const docsEligible =
@@ -376,6 +417,22 @@ async function detectRequirements(allLabels, prFiles, context, hasYamlLoadable)
     }
   }
 
+  // Check for missing developer docs. `new-feature-developer` requires a
+  // developers.esphome.io PR link, unless every changed file outside tests/ is
+  // in DEV_DOCS_EXEMPT_FILES (core validators documented via docstrings only).
+  if (allLabels.has('new-feature-developer')) {
+    const prBody = context.payload.pull_request.body || '';
+    const nonTestFiles = prFiles
+      .map(file => file.filename)
+      .filter(file => !file.startsWith('tests/'));
+    const onlyExemptFiles = nonTestFiles.every(file => DEV_DOCS_EXEMPT_FILES.includes(file));
+    const hasDevDocsLink = DEVELOPER_DOCS_PR_PATTERNS.some(pattern => pattern.test(prBody));
+
+    if (!onlyExemptFiles && !hasDevDocsLink) {
+      labels.add('needs-developer-docs');
+    }
+  }
+
   // Check for missing CODEOWNERS
   if (allLabels.has('new-component')) {
     const codeownersModified = prFiles.some(file =>

.github/scripts/auto-label-pr/index.js

@@ -53,7 +53,7 @@ module.exports = async ({ github, context }) => {
   });
   const currentLabels = currentLabelsData.map(label => label.name);
   const managedLabels = currentLabels.filter(label =>
-    label.startsWith('component: ') || MANAGED_LABELS.includes(label)
+    label.startsWith('component: ') || label.startsWith('platform: ') || MANAGED_LABELS.includes(label)
   );
 
   // Check for mega-PR early - if present, skip most automatic labeling
@@ -88,7 +88,7 @@ module.exports = async ({ github, context }) => {
 
   // Early exit for release and beta branches only
   if (baseRef === 'release' || baseRef === 'beta') {
-    const branchLabels = await detectMergeBranch(context);
+    const branchLabels = await detectMergeBranch(github, context);
     const finalLabels = Array.from(branchLabels);
 
     console.log('Computed labels (merge branch only):', finalLabels.join(', '));
@@ -118,7 +118,7 @@ module.exports = async ({ github, context }) => {
     deprecatedResult,
     maintainerAccess
   ] = await Promise.all([
-    detectMergeBranch(context),
+    detectMergeBranch(github, context),
     detectComponentPlatforms(changedFiles, apiData),
     detectNewComponents(github, context, prFiles),
     detectNewPlatforms(github, context, prFiles, apiData),

.github/scripts/auto-label-pr/reviews.js

@@ -42,8 +42,8 @@ function generateReviewMessages(finalLabels, originalLabelCount, deprecatedInfo,
     let message = `${TOO_BIG_MARKER}\n### 📦 Pull Request Size\n\n`;
 
     message +=
-      `Hey @${prAuthor}, thanks for the contribution! Just a heads up, ` +
-      `this PR is on the large side `;
+      `Hey @${prAuthor}, thanks for the contribution. This PR is on the ` +
+      `large side `;
 
     if (tooManyLabels && tooManyChanges) {
       message +=
@@ -57,16 +57,31 @@ function generateReviewMessages(finalLabels, originalLabelCount, deprecatedInfo,
     }
 
     message += `, which makes it harder for maintainers to review.\n\n`;
+    let condition;
+    if (tooManyLabels && tooManyChanges) {
+      condition =
+        `is at most ${TOO_BIG_THRESHOLD} lines (excluding tests) and touches ` +
+        `at most ${MAX_LABELS} components/areas`;
+    } else if (tooManyLabels) {
+      condition = `touches at most ${MAX_LABELS} components/areas`;
+    } else {
+      condition = `is at most ${TOO_BIG_THRESHOLD} lines (excluding tests)`;
+    }
     message +=
-      `Smaller, focused PRs tend to be reviewed much faster since they ` +
-      `fit into the short gaps between other maintainer work; large ones ` +
-      `often have to wait for a rare long uninterrupted block of time. ` +
-      `If you can break this up into smaller pieces that can be reviewed ` +
-      `independently, it will almost certainly land faster overall.\n\n`;
+      `**This PR will not be reviewed until it ${condition}.** We know ` +
+      `that is not what you want to hear after this much work, and we want ` +
+      `to be upfront so you do not wait for a review that is not coming: ` +
+      `please split the change. The label is removed automatically once ` +
+      `the PR ${condition}.\n\n`;
     message +=
-      `Before putting more time in, it's also worth popping into ` +
-      `\`#devs\` on [Discord](https://esphome.io/chat) so we can help ` +
-      `you scope things and flag anything already in flight.\n\n`;
+      `There is no exception you can request. Rarely, a maintainer agrees in ` +
+      `\`#devs\` on [Discord](https://esphome.io/chat) to review a change that ` +
+      `genuinely cannot be split as one piece and adds the \`mega-pr\` label, ` +
+      `but that is rare enough that you should plan on splitting rather than ` +
+      `wait for it. Smaller, focused PRs are picked up much faster because ` +
+      `they fit into the short gaps between other maintainer work. For a new ` +
+      `component, the first PR brings the hub and a single platform (for ` +
+      `example \`sensor\`); each further platform is its own PR on top of it.\n\n`;
     message +=
       `For more details (including how to split the work up), see: ` +
       `https://developers.esphome.io/contributing/submitting-your-work/` +
@@ -214,6 +229,7 @@ async function handleMaintainerAccessComment(github, context, maintainerAccess)
 }
 
 module.exports = {
+  generateReviewMessages,
   handleReviews,
   handleMaintainerAccessComment
 };

.github/scripts/auto-label-pr/tests/detectors.test.js

@@ -1,6 +1,14 @@
 const { describe, it } = require('node:test');
 const assert = require('node:assert/strict');
-const { detectNewPlatforms, detectNewComponents, detectPRSize } = require('../detectors');
+const {
+  detectMergeBranch,
+  detectNewPlatforms,
+  detectNewComponents,
+  detectPRSize,
+  detectPRTemplateCheckboxes,
+  detectRequirements,
+} = require('../detectors');
+const { MANAGED_LABELS } = require('../constants');
 
 // Minimal GitHub API mock — only repos.getContent is called by detectNewPlatforms/detectNewComponents
 // to check for CONFIG_SCHEMA in newly added files.
@@ -29,6 +37,122 @@ const API_DATA = {
 const WITH_SCHEMA = 'CONFIG_SCHEMA = cv.Schema({})';
 const WITHOUT_SCHEMA = 'CODEOWNERS = ["@esphome/core"]';
 
+// ---------------------------------------------------------------------------
+// detectMergeBranch
+// ---------------------------------------------------------------------------
+
+// Builds a fresh context for detectMergeBranch tests instead of mutating the
+// shared CONTEXT fixture above (which other describe blocks rely on).
+function makeMergeContext(baseRef, { stack, defaultBranch = 'dev' } = {}) {
+  const pull_request = { number: 1, base: { ref: baseRef } };
+  if (stack !== undefined) {
+    pull_request.stack = stack;
+  }
+  return {
+    repo: { owner: 'esphome', repo: 'esphome' },
+    payload: { pull_request, repository: { default_branch: defaultBranch } }
+  };
+}
+
+// A GitHub API mock exposing only rest.pulls.get, with a call counter so
+// tests can assert whether the API fallback was actually invoked.
+function makeStackGithub({ stack = null, error = null } = {}) {
+  const state = { calls: 0 };
+  const github = {
+    rest: {
+      pulls: {
+        get: async () => {
+          state.calls++;
+          if (error) throw error;
+          return { data: { stack } };
+        }
+      }
+    }
+  };
+  return { github, state };
+}
+
+const STACK_INFO = { base: { ref: 'dev' }, id: 71540, number: 17978, position: 3, size: 3 };
+
+describe('detectMergeBranch', () => {
+  it('base ref release adds merging-to-release only and never checks the stack', async () => {
+    const { github, state } = makeStackGithub({ stack: STACK_INFO });
+    const context = makeMergeContext('release', { stack: STACK_INFO });
+    const labels = await detectMergeBranch(github, context);
+    assert.deepEqual(Array.from(labels).sort(), ['merging-to-release']);
+    assert.equal(state.calls, 0);
+  });
+
+  it('base ref beta adds merging-to-beta only and never checks the stack', async () => {
+    const { github, state } = makeStackGithub({ stack: STACK_INFO });
+    const context = makeMergeContext('beta', { stack: STACK_INFO });
+    const labels = await detectMergeBranch(github, context);
+    assert.deepEqual(Array.from(labels).sort(), ['merging-to-beta']);
+    assert.equal(state.calls, 0);
+  });
+
+  it('stack present on the webhook payload adds stacked-pr without calling the API', async () => {
+    const { github, state } = makeStackGithub();
+    const context = makeMergeContext('feature-branch', { stack: STACK_INFO });
+    const labels = await detectMergeBranch(github, context);
+    assert.deepEqual(Array.from(labels).sort(), ['stacked-pr']);
+    assert.equal(state.calls, 0);
+  });
+
+  it('stack absent from payload falls back to the API and adds stacked-pr', async () => {
+    const { github, state } = makeStackGithub({ stack: STACK_INFO });
+    const context = makeMergeContext('feature-branch');
+    const labels = await detectMergeBranch(github, context);
+    assert.deepEqual(Array.from(labels).sort(), ['stacked-pr']);
+    assert.equal(state.calls, 1);
+  });
+
+  it('bottom of a stack (base ref dev, stack present) still adds stacked-pr', async () => {
+    const { github, state } = makeStackGithub();
+    const context = makeMergeContext('dev', { stack: STACK_INFO });
+    const labels = await detectMergeBranch(github, context);
+    assert.deepEqual(Array.from(labels).sort(), ['stacked-pr']);
+    assert.equal(state.calls, 0);
+  });
+
+  it('not stacked, base ref not dev adds chained-pr', async () => {
+    const { github } = makeStackGithub({ stack: null });
+    const context = makeMergeContext('feature-branch');
+    const labels = await detectMergeBranch(github, context);
+    assert.deepEqual(Array.from(labels).sort(), ['chained-pr']);
+  });
+
+  it('not stacked, base ref dev adds no labels', async () => {
+    const { github } = makeStackGithub({ stack: null });
+    const context = makeMergeContext('dev');
+    const labels = await detectMergeBranch(github, context);
+    assert.deepEqual(Array.from(labels).sort(), []);
+  });
+
+  it('a failed stack lookup falls back to not-stacked, so a feature-branch base adds chained-pr', async () => {
+    const { github, state } = makeStackGithub({ error: new Error('API unavailable') });
+    const context = makeMergeContext('feature-branch');
+    const labels = await detectMergeBranch(github, context);
+    assert.deepEqual(Array.from(labels).sort(), ['chained-pr']);
+    assert.equal(state.calls, 1);
+  });
+
+  it('base ref matches default branch adds no labels', async () => {
+    const { github } = makeStackGithub({ stack: null });
+    const context = makeMergeContext('other', { defaultBranch: 'other' });
+    const labels = await detectMergeBranch(github, context);
+    assert.deepEqual(Array.from(labels).sort(), []);
+  });
+
+  it('base ref dev when the default branch is main adds chained-pr', async () => {
+    const { github } = makeStackGithub({ stack: null });
+    const context = makeMergeContext('dev', { defaultBranch: 'main' });
+    const labels = await detectMergeBranch(github, context);
+    assert.deepEqual(Array.from(labels).sort(), ['chained-pr']);
+  });
+
+});
+
 // ---------------------------------------------------------------------------
 // detectNewPlatforms
 // ---------------------------------------------------------------------------
@@ -146,6 +270,125 @@ describe('detectNewComponents', () => {
   });
 });
 
+// ---------------------------------------------------------------------------
+// detectPRTemplateCheckboxes
+// ---------------------------------------------------------------------------
+
+const NEW_FEATURE_LINE = '- [x] New feature (non-breaking change which adds functionality)';
+const DEV_FEATURE_LINE = '- [x] New developer-facing feature (adds functionality for component developers; no end-user configuration change)';
+const DEV_FEATURE_LINE_UNTICKED = '- [ ] New developer-facing feature (adds functionality for component developers; no end-user configuration change)';
+
+function makeBodyContext(body) {
+  return { payload: { pull_request: { body } } };
+}
+
+describe('detectPRTemplateCheckboxes', () => {
+  it('ticked developer-facing feature checkbox adds new-feature-developer only', async () => {
+    const labels = await detectPRTemplateCheckboxes(makeBodyContext(DEV_FEATURE_LINE));
+    assert.ok(labels.has('new-feature-developer'));
+    assert.ok(!labels.has('new-feature'));
+  });
+
+  it('unticked developer-facing feature checkbox adds no label', async () => {
+    const labels = await detectPRTemplateCheckboxes(makeBodyContext(DEV_FEATURE_LINE_UNTICKED));
+    assert.ok(!labels.has('new-feature-developer'));
+  });
+
+  it('ticked new feature checkbox does not add new-feature-developer', async () => {
+    const labels = await detectPRTemplateCheckboxes(makeBodyContext(NEW_FEATURE_LINE));
+    assert.ok(labels.has('new-feature'));
+    assert.ok(!labels.has('new-feature-developer'));
+  });
+});
+
+// ---------------------------------------------------------------------------
+// detectRequirements
+// ---------------------------------------------------------------------------
+
+describe('detectRequirements', () => {
+  // PR body without any docs-PR link.
+  const NO_DOCS_CONTEXT = makeBodyContext('Just a description, no docs link.');
+  const USER_DOCS_CONTEXT = makeBodyContext('Docs: esphome/esphome.io#1234');
+  const DEV_DOCS_CONTEXT = makeBodyContext('Docs: esphome/developers.esphome.io#1234');
+  const DEV_DOCS_URL_CONTEXT = makeBodyContext('Docs: https://github.com/esphome/developers.esphome.io/pull/1234');
+
+  // File sets: a normal source change vs. one confined to the exempt core validators.
+  const SOURCE_FILES = [
+    { filename: 'esphome/components/foo/foo.py' },
+    { filename: 'tests/components/foo/common.yaml' },
+  ];
+  const VALIDATOR_FILES = [
+    { filename: 'esphome/config_validation.py' },
+    { filename: 'tests/unit_tests/test_config_validation.py' },
+  ];
+
+  it('new-feature-developer without has-tests adds needs-tests but not needs-docs', async () => {
+    const labels = await detectRequirements(new Set(['new-feature-developer']), SOURCE_FILES, NO_DOCS_CONTEXT, false);
+    assert.ok(labels.has('needs-tests'));
+    assert.ok(!labels.has('needs-docs'));
+  });
+
+  it('new-feature-developer with has-tests does not add needs-tests', async () => {
+    const labels = await detectRequirements(new Set(['new-feature-developer', 'has-tests']), SOURCE_FILES, NO_DOCS_CONTEXT, false);
+    assert.ok(!labels.has('needs-tests'));
+  });
+
+  it('new-feature without a docs link still adds needs-docs', async () => {
+    const labels = await detectRequirements(new Set(['new-feature', 'has-tests']), [], NO_DOCS_CONTEXT, false);
+    assert.ok(labels.has('needs-docs'));
+  });
+
+  it('new-feature-developer without a developer docs link adds needs-developer-docs', async () => {
+    const labels = await detectRequirements(new Set(['new-feature-developer', 'has-tests']), SOURCE_FILES, NO_DOCS_CONTEXT, false);
+    assert.ok(labels.has('needs-developer-docs'));
+  });
+
+  it('a developers.esphome.io shorthand link satisfies needs-developer-docs', async () => {
+    const labels = await detectRequirements(new Set(['new-feature-developer', 'has-tests']), SOURCE_FILES, DEV_DOCS_CONTEXT, false);
+    assert.ok(!labels.has('needs-developer-docs'));
+  });
+
+  it('a developers.esphome.io URL link satisfies needs-developer-docs', async () => {
+    const labels = await detectRequirements(new Set(['new-feature-developer', 'has-tests']), SOURCE_FILES, DEV_DOCS_URL_CONTEXT, false);
+    assert.ok(!labels.has('needs-developer-docs'));
+  });
+
+  it('a user docs (esphome.io) link does not satisfy needs-developer-docs', async () => {
+    const labels = await detectRequirements(new Set(['new-feature-developer', 'has-tests']), SOURCE_FILES, USER_DOCS_CONTEXT, false);
+    assert.ok(labels.has('needs-developer-docs'));
+  });
+
+  it('a developer docs link does not satisfy needs-docs for new-feature', async () => {
+    const labels = await detectRequirements(new Set(['new-feature', 'has-tests']), [], DEV_DOCS_CONTEXT, false);
+    assert.ok(labels.has('needs-docs'));
+  });
+
+  it('changes confined to core validator files are exempt from needs-developer-docs', async () => {
+    const labels = await detectRequirements(new Set(['new-feature-developer', 'has-tests']), VALIDATOR_FILES, NO_DOCS_CONTEXT, false);
+    assert.ok(!labels.has('needs-developer-docs'));
+  });
+
+  it('validator changes mixed with other source files are not exempt', async () => {
+    const prFiles = [...VALIDATOR_FILES, { filename: 'esphome/components/foo/foo.py' }];
+    const labels = await detectRequirements(new Set(['new-feature-developer', 'has-tests']), prFiles, NO_DOCS_CONTEXT, false);
+    assert.ok(labels.has('needs-developer-docs'));
+  });
+});
+
+// ---------------------------------------------------------------------------
+// MANAGED_LABELS
+// ---------------------------------------------------------------------------
+
+describe('MANAGED_LABELS', () => {
+  it('includes new-feature-developer so the workflow syncs it', () => {
+    assert.ok(MANAGED_LABELS.includes('new-feature-developer'));
+  });
+
+  it('includes needs-developer-docs so the workflow syncs it', () => {
+    assert.ok(MANAGED_LABELS.includes('needs-developer-docs'));
+  });
+});
+
 // ---------------------------------------------------------------------------
 // detectPRSize
 // ---------------------------------------------------------------------------

.github/scripts/auto-label-pr/tests/reviews.test.js

@@ -0,0 +1,38 @@
+const { describe, it } = require('node:test');
+const assert = require('node:assert/strict');
+const { generateReviewMessages } = require('../reviews');
+
+const MAX_LABELS = 15;
+const TOO_BIG_THRESHOLD = 1000;
+
+function tooBigMessage(labelCount, additions) {
+  const files = [{ filename: 'esphome/components/a/a.cpp', additions, deletions: 0 }];
+  const messages = generateReviewMessages(['too-big'], labelCount, null, files, additions, 0, 'someone', MAX_LABELS, TOO_BIG_THRESHOLD);
+  assert.equal(messages.length, 1);
+  return messages[0];
+}
+
+describe('too-big review message', () => {
+  it('names the line cap when the PR is too long', () => {
+    const message = tooBigMessage(3, 1500);
+    assert.match(message, /will not be reviewed until it is at most 1000 lines \(excluding tests\)\./);
+    assert.match(message, /removed automatically once the PR is at most 1000 lines/);
+    assert.doesNotMatch(message, /components\/areas\./);
+  });
+
+  it('names the area cap when the PR touches too many areas but is short', () => {
+    const message = tooBigMessage(20, 200);
+    assert.match(message, /will not be reviewed until it touches at most 15 components\/areas\./);
+    assert.doesNotMatch(message, /until it is at most 1000 lines/);
+  });
+
+  it('names both caps when both are exceeded', () => {
+    const message = tooBigMessage(20, 1500);
+    assert.match(message, /is at most 1000 lines \(excluding tests\) and touches at most 15 components\/areas\./);
+  });
+
+  it('tells new-component authors to bring one platform first', () => {
+    assert.match(tooBigMessage(3, 1500), /hub and a single platform/);
+    assert.match(tooBigMessage(3, 1500), /mega-pr/);
+  });
+});

.github/skills

@@ -0,0 +1 @@
+../.agents/skills

.github/workflows/auto-label-pr.yml

@@ -24,7 +24,7 @@ jobs:
     if: github.event.pull_request.state == 'open' && (github.event.action != 'labeled' || github.event.sender.type != 'Bot')
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Generate a token
         id: generate-token
@@ -35,7 +35,7 @@ jobs:
           # Scope the minted App token to the minimum needed by auto-label-pr/*.js.
           permission-contents: read       # repos.getContent for CODEOWNERS and file lookups in detectors.js
           permission-issues: write        # listLabelsOnIssue, addLabels, removeLabel, list/createComment
-          permission-pull-requests: write  # pulls.listFiles, list/create/update/dismissReview
+          permission-pull-requests: write  # pulls.get, pulls.listFiles, list/create/update/dismissReview
 
       - name: Auto Label PR
         uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0

.github/workflows/ci-api-proto.yml

@@ -21,15 +21,15 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Set up Python
-        uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6.3.0
+        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
         with:
           python-version: "3.12"
       - name: Set up uv
         # ``--system`` (below) installs into the setup-python interpreter;
         # no venv is created or restored by this workflow.
-        uses: astral-sh/setup-uv@11f9893b081a58869d3b5fccaea48c9e9e46f990 # v8.3.2
+        uses: astral-sh/setup-uv@c18668ad3cf93ea998bef934396af7bb5c839dc7 # v10.2.0
         with:
           enable-cache: true
           # Pull-request-only workflow: a save could never be shared and
@@ -41,10 +41,32 @@ jobs:
           version: "0.11.15"
 
       - name: Install apt dependencies
+        # PR-only workflow, so nothing on dev could seed a shared apt cache
+        # entry; the cached apt action would save one copy per PR. Plain apt
+        # with every call bounded: the apt.conf.d timeouts make a dead
+        # mirror fail over in seconds, and timeout runs under sudo so it can
+        # kill apt-get itself. Install without update first: image lists are
+        # fresh, and the index refresh is what a congested mirror makes slow.
+        timeout-minutes: 15
         run: |
-          sudo apt update
-          sudo apt-cache show protobuf-compiler
-          sudo apt install -y protobuf-compiler
+          sudo tee /etc/apt/apt.conf.d/99ci-acquire-timeouts >/dev/null <<'EOF'
+          Acquire::Retries "1";
+          Acquire::http::Timeout "15";
+          Acquire::https::Timeout "15";
+          EOF
+          # Common path: the image's package lists are fresh enough.
+          if sudo DEBIAN_FRONTEND=noninteractive timeout -k 15 90 \
+              apt-get install -y protobuf-compiler; then
+            protoc --version
+            exit 0
+          fi
+          # Rescue path: refresh the lists once with a generous bound; the
+          # apt config already fails a stalled mirror over quickly.
+          sudo DEBIAN_FRONTEND=noninteractive timeout -k 10 30 \
+            dpkg --configure -a || true
+          sudo timeout -k 15 300 apt-get update
+          sudo DEBIAN_FRONTEND=noninteractive timeout -k 15 300 \
+            apt-get install -y protobuf-compiler
           protoc --version
       - name: Install python dependencies
         run: uv pip install --system aioesphomeapi -c requirements.txt -r requirements_dev.txt

.github/workflows/ci-docker.yml

@@ -12,15 +12,14 @@ on:
       - ".github/workflows/ci-docker.yml"
       - "requirements*.txt"
       - "pyproject.toml"
-      - "platformio.ini"
       - "esphome/idf_component.yml"
-      - "script/platformio_install_deps.py"
       # Core, build pipeline, toolchain, and target-platform changes can change
       # how a toolchain is set up or built, so re-run the per-toolchain compile
       # smoke test when they change.
       - "esphome/core/**"
       - "esphome/writer.py"
       - "esphome/build_gen/**"
+      - "esphome/build_helpers/**"
       - "esphome/espidf/**"
       - "esphome/platformio/**"
       - "esphome/components/bk72xx/**"
@@ -61,21 +60,23 @@ jobs:
       tag: ${{ steps.tag.outputs.tag }}
       push: ${{ steps.tag.outputs.push }}
     steps:
-      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Set up Python
-        uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6.3.0
+        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
         with:
           python-version: "3.12"
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@bb05f3f5519dd87d3ba754cc423b652a5edd6d2c # v4.2.0
+        uses: docker/setup-buildx-action@594f3bf4285d9ea8dc53c9a0c9c4092420091003 # v4.4.0
 
       - name: Determine tag and whether to push
         id: tag
+        env:
+          HEAD_REF: ${{ github.head_ref || github.ref_name }}
         run: |
           # Sanitize the branch name into a valid docker tag: replace invalid
           # characters, ensure the first character is valid (tags must start
           # with [A-Za-z0-9_]), and cap the length at 128 characters.
-          branch="${{ github.head_ref || github.ref_name }}"
+          branch="$HEAD_REF"
           tag="${branch//[^a-zA-Z0-9_.-]/-}"
           case "$tag" in
             [a-zA-Z0-9_]*) ;;
@@ -96,7 +97,7 @@ jobs:
 
       - name: Log in to the GitHub container registry
         if: steps.tag.outputs.push == 'true'
-        uses: docker/login-action@af1e73f918a031802d376d3c8bbc3fe56130a9b0 # v4.4.0
+        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4.6.0
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
@@ -117,16 +118,22 @@ jobs:
       # pushed image) keeps it working for fork PRs, which never push to ghcr.io.
       - name: Export image for compile-test
         if: matrix.os == 'ubuntu-24.04' && matrix.build_type == 'docker'
-        run: docker save "ghcr.io/esphome/esphome-amd64:${{ steps.tag.outputs.tag }}" | gzip > compile-test-image.tar.gz
+        # zstd over gzip: docker save is on the critical path for every
+        # compile-test job, and zstd -T0 is multithreaded (export 50s -> 9s).
+        # docker load auto-detects the format; its time is layer extraction,
+        # not decompression, so it is unchanged. shell: bash adds pipefail so
+        # a failed docker save cannot upload a truncated artifact.
+        shell: bash
+        run: docker save "ghcr.io/esphome/esphome-amd64:${{ steps.tag.outputs.tag }}" | zstd -T0 -3 > compile-test-image.tar.zst
 
       - name: Upload compile-test image artifact
         if: matrix.os == 'ubuntu-24.04' && matrix.build_type == 'docker'
         uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
-          # The tar is already gzipped, so upload it as-is. archive: false skips
-          # the redundant zip and makes the file name the artifact name (the
-          # `name` input is ignored in that mode).
-          path: compile-test-image.tar.gz
+          # The tar is already compressed, so upload it as-is. archive: false
+          # skips the redundant zip and makes the file name the artifact name
+          # (the `name` input is ignored in that mode).
+          path: compile-test-image.tar.zst
           retention-days: 1
           archive: false
 
@@ -145,16 +152,16 @@ jobs:
           - "ha-addon"
           - "docker"
     steps:
-      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Set up Python
-        uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6.3.0
+        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
         with:
           python-version: "3.12"
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@bb05f3f5519dd87d3ba754cc423b652a5edd6d2c # v4.2.0
+        uses: docker/setup-buildx-action@594f3bf4285d9ea8dc53c9a0c9c4092420091003 # v4.4.0
 
       - name: Log in to the GitHub container registry
-        uses: docker/login-action@af1e73f918a031802d376d3c8bbc3fe56130a9b0 # v4.4.0
+        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4.6.0
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
@@ -180,8 +187,6 @@ jobs:
       contents: read  # actions/checkout to load the test configs
     strategy:
       fail-fast: false
-      # Cap concurrency so this smoke test doesn't hog all the shared runners.
-      max-parallel: 2
       matrix:
         # One entry per distinct toolchain. ESP32 variants (c3/c6/s2/s3/p4)
         # share a toolchain bundle, so esp32 is exercised on the base variant
@@ -191,6 +196,7 @@ jobs:
         # the default.
         id:
           - esp8266-arduino
+          - esp8266-arduino-native
           - esp32-arduino-platformio
           - esp32-arduino-esp-idf
           - esp32-idf-platformio
@@ -202,16 +208,17 @@ jobs:
           - nrf52
           - host
     steps:
-      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Download image artifact
         uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
         with:
-          name: compile-test-image.tar.gz
+          name: compile-test-image.tar.zst
       - name: Load image
-        run: docker load --input compile-test-image.tar.gz
+        run: docker load --input compile-test-image.tar.zst
       - name: Compile ${{ matrix.id }}
         run: |
           docker run --rm \
             -v "${{ github.workspace }}/docker/test_configs:/config" \
+            -e ESPHOME_LDGEN_STRICT=1 \
             "ghcr.io/esphome/esphome-amd64:${{ needs.check-docker.outputs.tag }}" \
             compile "${{ matrix.id }}.yaml"

.github/workflows/ci-github-scripts.yml

@@ -20,7 +20,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out code from GitHub
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Run tests
         working-directory: .github/scripts/auto-label-pr

.github/workflows/ci-memory-impact-comment.yml

@@ -49,7 +49,7 @@ jobs:
 
       - name: Check out code from base repository
         if: steps.pr.outputs.skip != 'true'
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           # Always check out from the base repository (esphome/esphome), never from forks
           # Use the PR's target branch to ensure we run trusted code from the main repo

.github/workflows/codeowner-approved-label-update.yml

@@ -26,7 +26,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout base branch
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           ref: ${{ github.event.pull_request.base.sha }}
           sparse-checkout: |

.github/workflows/codeowner-review-request.yml

@@ -29,7 +29,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout base branch
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           ref: ${{ github.event.pull_request.base.sha }}
 

.github/workflows/codeql.yml

@@ -52,11 +52,11 @@ jobs:
             # your codebase is analyzed, see https://docs.github.com/en/code-security/code-scanning/creating-an-advanced-setup-for-code-scanning/codeql-code-scanning-for-compiled-languages
     steps:
       - name: Checkout repository
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       # Initializes the CodeQL tools for scanning.
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@99df26d4f13ea111d4ec1a7dddef6063f76b97e9 # v4.37.0
+        uses: github/codeql-action/init@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
         with:
           languages: ${{ matrix.language }}
           build-mode: ${{ matrix.build-mode }}
@@ -84,6 +84,6 @@ jobs:
           exit 1
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@99df26d4f13ea111d4ec1a7dddef6063f76b97e9 # v4.37.0
+        uses: github/codeql-action/analyze@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
         with:
           category: "/language:${{matrix.language}}"

.github/workflows/external-component-bot.yml

@@ -125,14 +125,20 @@ jobs:
             }
 
             async function getEsphomeAndComponentChanges(github, owner, repo, prNumber) {
-                const changedFiles = await github.rest.pulls.listFiles({
-                    owner: owner,
-                    repo: repo,
-                    pull_number: prNumber,
-                });
+                const changedFiles = await github.paginate(
+                    github.rest.pulls.listFiles,
+                    {
+                        owner: owner,
+                        repo: repo,
+                        pull_number: prNumber,
+                        per_page: 100,
+                    }
+                );
 
-                const esphomeChanges = changedFiles.data
-                    .filter(file => file.filename !== "esphome/core/defines.h" && file.filename.startsWith('esphome/'))
+                // Files used only for development and CI, which do not affect use as an external component
+                const ignoredFiles = ["esphome/core/defines.h", "esphome/idf_component.yml"];
+                const esphomeChanges = changedFiles
+                    .filter(file => !ignoredFiles.includes(file.filename) && file.filename.startsWith('esphome/'))
                     .map(file => {
                         const match = file.filename.match(/esphome\/([^/]+)/);
                         return match ? match[1] : null;
@@ -144,7 +150,7 @@ jobs:
                 }
 
                 const uniqueEsphomeChanges = [...new Set(esphomeChanges)];
-                const componentChanges = changedFiles.data
+                const componentChanges = changedFiles
                     .filter(file => file.filename.startsWith('esphome/components/'))
                     .map(file => {
                         const match = file.filename.match(/esphome\/components\/([^/]+)\//);

.github/workflows/lock.yml

@@ -14,4 +14,4 @@ jobs:
     permissions:
       issues: write         # issues.lock on closed issues
       pull-requests: write  # issues.lock on closed pull requests
-    uses: esphome/workflows/.github/workflows/lock.yml@025a1e6255610c498ed590403b7e510b69e474df  # 2026.4.1
+    uses: esphome/workflows/.github/workflows/lock.yml@cc3e76de337dc59bc1cba8da58d963cd23b873f1  # 2026.9.0

.github/workflows/pr-title-check.yml

@@ -16,7 +16,7 @@ jobs:
     name: Validate PR title
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
         with:

.github/workflows/release-nightly.yml

@@ -0,0 +1,38 @@
+---
+name: Nightly Dev Release
+
+# Works out the dated dev tag and starts the release workflow with it, so that
+# the release run is named after the tag it builds. A workflow run name is
+# fixed when the run starts and cannot read a file or the current date.
+
+on:
+  schedule:
+    - cron: "0 2 * * *"
+
+permissions:
+  contents: read  # actions/checkout to read the version from esphome/const.py
+
+jobs:
+  trigger:
+    name: Start release build
+    if: github.repository == 'esphome/esphome'
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read  # actions/checkout to read the version from esphome/const.py
+      actions: write  # gh workflow run starts release.yml
+    steps:
+      - name: Check out the repository
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - name: Start the release workflow
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          VERSION=$(sed -n -E "s/^__version__\s+=\s+\"(.+)\"$/\1/p" esphome/const.py)
+          if [[ -z "$VERSION" ]]; then
+            echo "::error::Could not read __version__ from esphome/const.py"
+            exit 1
+          fi
+          TAG="${VERSION}$(date --utc '+%Y%m%d')"
+          echo "Starting release build for ${TAG}"
+          gh workflow run release.yml --ref "${GITHUB_REF_NAME}" --field tag="${TAG}"

.github/workflows/release.yml

@@ -1,12 +1,23 @@
 ---
 name: Publish Release
 
+# Releases (production and beta) are named after the version they publish.
+# Dev builds are named after the dated dev tag, which is passed in by the
+# nightly workflow because a run name cannot compute it itself.
+run-name: ${{ github.event.inputs.tag || github.event.release.tag_name || format('Manual build ({0})', github.ref_name) }}
+
 on:
   workflow_dispatch:
+    inputs:
+      tag:
+        description: >-
+          Tag to build. Only supported on dev, where the nightly workflow
+          uses it. Leave empty to build the version from esphome/const.py
+          with today's date appended.
+        required: false
+        default: ""
   release:
     types: [published]
-  schedule:
-    - cron: "0 2 * * *"
 
 permissions:
   contents: read  # actions/checkout for all jobs; deploy jobs add their own scopes when they need to write
@@ -20,9 +31,11 @@ jobs:
       branch_build: ${{ steps.tag.outputs.branch_build }}
       deploy_env: ${{ steps.tag.outputs.deploy_env }}
     steps:
-      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Get tag
         id: tag
+        env:
+          INPUT_TAG: ${{ github.event.inputs.tag }}
         # yamllint disable rule:line-length
         run: |
           if [[ "${{ github.event_name }}" = "release" ]]; then
@@ -34,12 +47,23 @@ jobs:
               ENVIRONMENT="production"
             fi
           else
-            TAG=$(cat esphome/const.py | sed -n -E "s/^__version__\s+=\s+\"(.+)\"$/\1/p")
-            today="$(date --utc '+%Y%m%d')"
-            TAG="${TAG}${today}"
             BRANCH=${GITHUB_REF#refs/heads/}
+            # The nightly workflow passes the finished tag so that the run name
+            # matches what is built. Without it, work it out here.
+            TAG="${INPUT_TAG}"
+            if [[ -n "$TAG" && "$BRANCH" != "dev" ]]; then
+              echo "::error::The tag input is only supported on dev. A build from ${BRANCH} has to use the tag worked out here, which carries the branch name, so that it cannot publish over the dev, beta, latest or stable images."
+              exit 1
+            fi
+            if [[ -z "$TAG" ]]; then
+              TAG=$(cat esphome/const.py | sed -n -E "s/^__version__\s+=\s+\"(.+)\"$/\1/p")
+              today="$(date --utc '+%Y%m%d')"
+              TAG="${TAG}${today}"
+              if [[ "$BRANCH" != "dev" ]]; then
+                TAG="${TAG}-${BRANCH}"
+              fi
+            fi
             if [[ "$BRANCH" != "dev" ]]; then
-              TAG="${TAG}-${BRANCH}"
               BRANCH_BUILD="true"
               ENVIRONMENT=""
             else
@@ -60,9 +84,9 @@ jobs:
       contents: read   # actions/checkout to build the sdist/wheel
       id-token: write  # OIDC token for PyPI Trusted Publishing (pypa/gh-action-pypi-publish)
     steps:
-      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Set up Python
-        uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6.3.0
+        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
         with:
           python-version: "3.x"
       - name: Build
@@ -70,7 +94,7 @@ jobs:
           pip3 install build
           python3 -m build
       - name: Publish
-        uses: pypa/gh-action-pypi-publish@cef221092ed1bacb1cc03d23a2d87d1d172e277b # v1.14.0
+        uses: pypa/gh-action-pypi-publish@dc37677b2e1c63e2034f94d8a5b11f265b73ba33 # v1.14.2
         with:
           skip-existing: true
 
@@ -92,22 +116,22 @@ jobs:
             os: "ubuntu-24.04-arm"
 
     steps:
-      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Set up Python
-        uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6.3.0
+        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
         with:
           python-version: "3.12"
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@bb05f3f5519dd87d3ba754cc423b652a5edd6d2c # v4.2.0
+        uses: docker/setup-buildx-action@594f3bf4285d9ea8dc53c9a0c9c4092420091003 # v4.4.0
 
       - name: Log in to docker hub
-        uses: docker/login-action@af1e73f918a031802d376d3c8bbc3fe56130a9b0 # v4.4.0
+        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4.6.0
         with:
           username: ${{ secrets.DOCKER_USER }}
           password: ${{ secrets.DOCKER_PASSWORD }}
       - name: Log in to the GitHub container registry
-        uses: docker/login-action@af1e73f918a031802d376d3c8bbc3fe56130a9b0 # v4.4.0
+        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4.6.0
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
@@ -168,7 +192,7 @@ jobs:
           - ghcr
           - dockerhub
     steps:
-      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Download digests
         uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
@@ -178,17 +202,17 @@ jobs:
           merge-multiple: true
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@bb05f3f5519dd87d3ba754cc423b652a5edd6d2c # v4.2.0
+        uses: docker/setup-buildx-action@594f3bf4285d9ea8dc53c9a0c9c4092420091003 # v4.4.0
 
       - name: Log in to docker hub
         if: matrix.registry == 'dockerhub'
-        uses: docker/login-action@af1e73f918a031802d376d3c8bbc3fe56130a9b0 # v4.4.0
+        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4.6.0
         with:
           username: ${{ secrets.DOCKER_USER }}
           password: ${{ secrets.DOCKER_PASSWORD }}
       - name: Log in to the GitHub container registry
         if: matrix.registry == 'ghcr'
-        uses: docker/login-action@af1e73f918a031802d376d3c8bbc3fe56130a9b0 # v4.4.0
+        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4.6.0
         with:
           registry: ghcr.io
           username: ${{ github.actor }}

.github/workflows/stale.yml

@@ -6,61 +6,60 @@ on:
     - cron: "30 0 * * *"
   workflow_dispatch:
 
-permissions:
-  issues: write         # actions/stale labels, comments on, and closes stale issues
-  pull-requests: write  # actions/stale labels, comments on, and closes stale pull requests
-
-concurrency:
-  group: lock
+# The reusable workflow authenticates as the ESPHome GitHub App, so GITHUB_TOKEN
+# needs no permissions at all.
+permissions: {}
 
 jobs:
   stale:
     if: github.repository_owner == 'esphome'
-    runs-on: ubuntu-latest
-    steps:
-      - name: Stale
-        uses: actions/stale@eb5cf3af3ac0a1aa4c9c45633dd1ae542a27a899 # v10.3.0
-        with:
-          debug-only: ${{ github.ref != 'refs/heads/dev' }} # Dry-run when not run on dev branch
-          remove-stale-when-updated: true
-          operations-per-run: 400
+    # No GITHUB_TOKEN permissions: the reusable workflow mints an ESPHome
+    # GitHub App token so the labels, comments and closures come from
+    # esphome[bot] instead of github-actions[bot].
+    uses: esphome/workflows/.github/workflows/stale.yml@4fbce13026c393d6eb6b247e394dcd9ef1af76c2  # main
+    secrets:
+      ESPHOME_GITHUB_APP_PRIVATE_KEY: ${{ secrets.ESPHOME_GITHUB_APP_PRIVATE_KEY }}
+    with:
+      # Live only on dev: a workflow_dispatch from any other branch is a dry run
+      dry-run: ${{ github.ref != 'refs/heads/dev' }}
+      days-before-stale: 90
+      days-before-stale-conflicting: 30
+      days-before-close: 7
+      stale-label: stale
+      exempt-label: not-stale
+      conflict-label: needs-rebase
+      ignored-users: esphbot,codecov-commenter
+      stale-pr-message: >
+        There hasn't been any activity on this pull request recently. This
+        pull request has been automatically marked as stale because of that
+        and will be closed if no further activity occurs within 7 days.
 
-          # The 90 day stale policy for PRs
-          # - PRs
-          # - No PRs marked as "not-stale"
-          # - No Issues (see below)
-          days-before-pr-stale: 90
-          days-before-pr-close: 7
-          stale-pr-label: "stale"
-          exempt-pr-labels: "not-stale"
-          stale-pr-message: >
-            There hasn't been any activity on this pull request recently. This
-            pull request has been automatically marked as stale because of that
-            and will be closed if no further activity occurs within 7 days.
+        If you are the author of this PR, please leave a comment if you want
+        to keep it open. Also, please merge the latest dev branch into your
+        branch to ensure that it's up to date with the latest changes.
 
-            If you are the author of this PR, please leave a comment if you want
-            to keep it open. Also, please rebase your PR onto the latest dev
-            branch to ensure that it's up to date with the latest changes.
+        Thank you for your contribution!
+      conflict-pr-message: >
+        This pull request has merge conflicts. Please merge the latest dev
+        branch into your branch to resolve them.
+      stale-conflicting-pr-message: >
+        The merge conflicts on this pull request have not been resolved for
+        30 days, so it has been marked as stale and will be closed if they
+        are not resolved within 7 days.
 
-            Thank you for your contribution!
+        Please merge the latest dev branch into your branch. Once the pull
+        request is mergeable again the stale label is removed.
 
-          # The 90 day stale policy for Issues
-          # - Issues
-          # - No Issues marked as "not-stale"
-          # - No PRs (see above)
-          days-before-issue-stale: 90
-          days-before-issue-close: 7
-          stale-issue-label: "stale"
-          exempt-issue-labels: "not-stale"
-          stale-issue-message: >
-            There hasn't been any activity on this issue recently. Due to the
-            high number of incoming GitHub notifications, we have to clean some
-            of the old issues, as many of them have already been resolved with
-            the latest updates.
+        Thank you for your contribution!
+      stale-issue-message: >
+        There hasn't been any activity on this issue recently. Due to the
+        high number of incoming GitHub notifications, we have to clean some
+        of the old issues, as many of them have already been resolved with
+        the latest updates.
 
-            Please make sure to update to the latest ESPHome version and
-            check if that solves the issue. Let us know if that works for you by
-            adding a comment 👍
+        Please make sure to update to the latest ESPHome version and
+        check if that solves the issue. Let us know if that works for you by
+        adding a comment 👍
 
-            This issue has now been marked as stale and will be closed if no
-            further activity occurs. Thank you for your contributions.
+        This issue has now been marked as stale and will be closed if no
+        further activity occurs. Thank you for your contributions.

.github/workflows/status-check-labels.yml

@@ -5,11 +5,7 @@ on:
     types: [opened, reopened, labeled, unlabeled, synchronize]
 
 permissions:
-  pull-requests: read  # issues.listLabelsOnIssue to detect blocking labels (needs-docs, merge-after-release, chained-pr)
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
-  cancel-in-progress: true
+  pull-requests: read  # issues.listLabelsOnIssue to detect blocking labels (needs-docs, needs-developer-docs, merge-after-release, chained-pr)
 
 jobs:
   check:
@@ -20,7 +16,7 @@ jobs:
         uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
         with:
           script: |
-            const blockingLabels = ['needs-docs', 'merge-after-release', 'chained-pr'];
+            const blockingLabels = ['needs-docs', 'needs-developer-docs', 'merge-after-release', 'chained-pr'];
             const { data: labels } = await github.rest.issues.listLabelsOnIssue({
               owner: context.repo.owner,
               repo: context.repo.repo,

.github/workflows/sync-dependency-versions.yml

@@ -0,0 +1,96 @@
+# Keeps pre-commit hook revs in sync with the requirements files.
+#
+# Dependabot only bumps the pins in requirements*.txt. Some of those tools
+# are pinned again as hook revs in .pre-commit-config.yaml. This workflow
+# runs script/sync_dependency_versions.py against the pull request branch
+# and pushes a commit with the revs updated.
+
+name: Sync dependency versions
+
+on:
+  # pull_request_target rather than pull_request so the App secret is
+  # available on Dependabot pull requests (pull_request runs opened by
+  # Dependabot only see Dependabot secrets). The job below only touches
+  # branches in this repository and only ever executes the script from the
+  # base branch checkout, so fork code never runs with the token.
+  pull_request_target:
+    types: [opened, synchronize, reopened]
+    branches:
+      - dev
+    paths:
+      - requirements_dev.txt
+      - requirements_test.txt
+      - .pre-commit-config.yaml
+      - script/sync_dependency_versions.py
+
+# The push to the pull request branch uses the App token minted below, so
+# the workflow's GITHUB_TOKEN does not need any scopes.
+permissions: {}
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+jobs:
+  sync:
+    name: Sync pinned versions
+    runs-on: ubuntu-latest
+    # Same-repository branches only: a push to a fork is not possible with
+    # this token, and it keeps untrusted heads out of a privileged job.
+    if: >-
+      github.repository == 'esphome/esphome'
+      && github.event.pull_request.head.repo.full_name == github.repository
+    steps:
+      - name: Generate a token
+        id: generate-token
+        uses: actions/create-github-app-token@bcd2ba49218906704ab6c1aa796996da409d3eb1 # v3.2.0
+        with:
+          client-id: ${{ vars.ESPHOME_GITHUB_APP_CLIENT_ID }}
+          private-key: ${{ secrets.ESPHOME_GITHUB_APP_PRIVATE_KEY }}
+          # A push made with the workflow's own GITHUB_TOKEN would not start
+          # CI on the new commit; a push with the App token does.
+          permission-contents: write  # git push of the sync commit to the pull request branch
+
+      - name: Check out base branch
+        # Provides the script that runs below. Deliberately the base branch
+        # so the pull request cannot change what executes here.
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          ref: ${{ github.event.pull_request.base.sha }}
+          persist-credentials: false
+
+      - name: Check out pull request branch
+        # No allow-unsafe-pr-checkout here on purpose: checkout v7 only
+        # refuses heads that live in a different repository, and the job
+        # condition above already limits runs to same-repository branches.
+        # Leaving it off keeps that refusal as a backstop for fork heads.
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          ref: ${{ github.event.pull_request.head.ref }}
+          path: pull-request
+          token: ${{ steps.generate-token.outputs.token }}
+
+      - name: Set up Python
+        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
+        with:
+          python-version: "3.12"
+
+      - name: Install yamlrocks
+        # The script edits YAML through yamlrocks. Take the pin from the
+        # base branch requirements so this workflow has no copy of its own.
+        run: pip install "$(grep -E '^yamlrocks==' requirements_test.txt | cut -d'#' -f1)"
+
+      - name: Sync pinned versions
+        run: python script/sync_dependency_versions.py --root pull-request
+
+      - name: Push changes
+        working-directory: pull-request
+        run: |
+          if git diff --quiet; then
+            echo "All pinned versions already match the requirements files."
+            exit 0
+          fi
+          git config user.name "esphome[bot]"
+          git config user.email "115708604+esphome[bot]@users.noreply.github.com"
+          git commit -am "Sync pinned tool versions with requirements files"
+          git push

.github/workflows/sync-device-classes.yml

@@ -28,26 +28,26 @@ jobs:
           permission-pull-requests: write  # pulls.create / pulls.update to open or refresh the sync PR
 
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
       - name: Checkout Home Assistant
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           repository: home-assistant/core
           path: lib/home-assistant
 
       - name: Setup Python
-        uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6.3.0
+        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
         with:
           python-version: "3.14"
 
       - name: Set up uv
         # An order of magnitude faster than pip on cold boots, with its
         # own wheel cache. ``--system`` (below) installs into the
-        # setup-python interpreter so subsequent ``pre-commit`` /
+        # setup-python interpreter so subsequent ``prek`` /
         # ``script/run-in-env.py`` steps find the deps without a
         # ``uv run`` prefix.
-        uses: astral-sh/setup-uv@11f9893b081a58869d3b5fccaea48c9e9e46f990 # v8.3.2
+        uses: astral-sh/setup-uv@c18668ad3cf93ea998bef934396af7bb5c839dc7 # v10.2.0
         with:
           enable-cache: true
           # Pin uv version so the action does not have to fetch the
@@ -58,19 +58,19 @@ jobs:
       - name: Install Home Assistant
         run: |
           uv pip install --system -e lib/home-assistant
-          uv pip install --system -r requirements.txt -r requirements_test.txt pre-commit
+          uv pip install --system -r requirements.txt -r requirements_test.txt
 
       - name: Sync
         run: |
           python ./script/sync-device_class.py
 
-      - name: Apply pre-commit auto-fixes
+      - name: Apply prek auto-fixes
         # First pass: let formatters (ruff, end-of-file-fixer, etc.) modify
-        # files. pre-commit exits non-zero whenever a hook touches anything,
+        # files. prek exits non-zero whenever a hook touches anything,
         # which would otherwise abort the workflow before the auto-fixes
         # can flow into the sync PR.
         #
-        # SKIP:
+        # PREK_SKIP:
         #   - no-commit-to-branch is a local guard against committing on
         #     dev/release/beta; CI runs on dev by definition, and
         #     peter-evans/create-pull-request creates the branch itself.
@@ -79,25 +79,25 @@ jobs:
         #     the runtime deps (HA + requirements*.txt); main CI already
         #     gates pylint on real PRs.
         env:
-          SKIP: pylint,no-commit-to-branch
-        run: python script/run-in-env.py pre-commit run --all-files || true
+          PREK_SKIP: pylint,no-commit-to-branch
+        run: python script/run-in-env.py prek run --all-files || true
 
-      - name: Verify pre-commit clean
+      - name: Verify prek clean
         # Second pass: re-run all hooks against the now-fixed tree.
         # Auto-fixers exit 0 (nothing to change); any remaining failure
         # from a check-only hook (flake8 / yamllint / ci-custom) is a
-        # real issue and fails the workflow loudly. Same SKIP list as
+        # real issue and fails the workflow loudly. Same PREK_SKIP list as
         # above for the same reasons.
         env:
-          SKIP: pylint,no-commit-to-branch
-        run: python script/run-in-env.py pre-commit run --all-files
+          PREK_SKIP: pylint,no-commit-to-branch
+        run: python script/run-in-env.py prek run --all-files
 
       - name: Commit changes
         uses: peter-evans/create-pull-request@5f6978faf089d4d20b00c7766989d076bb2fc7f1 # v8.1.1
         with:
           commit-message: "Synchronise Device Classes from Home Assistant"
-          committer: esphomebot <esphome@openhomefoundation.org>
-          author: esphomebot <esphome@openhomefoundation.org>
+          committer: esphome[bot] <115708604+esphome[bot]@users.noreply.github.com>
+          author: esphome[bot] <115708604+esphome[bot]@users.noreply.github.com>
           branch: sync/device-classes
           delete-branch: true
           title: "Synchronise Device Classes from Home Assistant"

.github/workflows/sync-integration-durations.yml

@@ -0,0 +1,98 @@
+---
+name: Refresh integration test durations
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: "45 5 * * 1"
+
+# Repo writes (branch push, PR open) happen via the App token minted below,
+# so the workflow's GITHUB_TOKEN does not need any write scopes.
+permissions:
+  contents: read
+  actions: read  # gh api / gh run download for the CI junit artifacts
+
+jobs:
+  sync:
+    name: Refresh integration test durations
+    runs-on: ubuntu-latest
+    if: github.repository == 'esphome/esphome'
+    steps:
+      - name: Generate a token
+        id: generate-token
+        uses: actions/create-github-app-token@bcd2ba49218906704ab6c1aa796996da409d3eb1 # v3.2.0
+        with:
+          client-id: ${{ vars.ESPHOME_GITHUB_APP_CLIENT_ID }}
+          private-key: ${{ secrets.ESPHOME_GITHUB_APP_PRIVATE_KEY }}
+          permission-contents: write       # push the sync branch
+          permission-pull-requests: write  # open or refresh the sync PR
+
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - name: Setup Python
+        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
+        with:
+          python-version: "3.13"
+
+      - name: Refresh from the newest usable dev run
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          # Only full matrix dev runs upload junit-integration-* artifacts
+          # (see the integration-tests job); the merge script re-checks
+          # coverage regardless.
+          # Newest-first candidates via their bucket-0 artifact. Fork PRs run
+          # their own ci.yml, so name and branch are spoofable; require
+          # same-repo. Assignment failures trip set -e and fail loudly.
+          candidates=$(
+            gh api "repos/${GITHUB_REPOSITORY}/actions/artifacts?name=junit-integration-0&per_page=100" \
+              --jq '.artifacts[] | select(.expired | not) | .workflow_run
+                    | select(.head_branch == "dev" and .head_repository_id != null
+                             and .head_repository_id == .repository_id)
+                    | .id'
+          )
+          # Green runs first, then the rest newest first; a run missing a
+          # bucket fails the coverage check and the next one is tried
+          green=""
+          rest=""
+          for id in ${candidates}; do
+            conclusion=$(gh api "repos/${GITHUB_REPOSITORY}/actions/runs/${id}" --jq '.conclusion // ""')
+            if [ "${conclusion}" = "success" ]; then
+              green="${green} ${id}"
+            elif [ -n "${conclusion}" ]; then
+              rest="${rest} ${id}"
+            fi
+          done
+          # helpers.py imports colorama; the script needs nothing else
+          pip install colorama
+          for id in ${green} ${rest}; do
+            rm -rf /tmp/junit
+            if ! gh run download "${id}" --repo "${GITHUB_REPOSITORY}" -p "junit-integration-*" -D /tmp/junit; then
+              echo "::warning::Could not download artifacts for run ${id}; trying the next"
+              continue
+            fi
+            status=0
+            python script/update_integration_test_durations.py /tmp/junit || status=$?
+            if [ "${status}" -eq 0 ]; then
+              echo "Refreshed from run ${id}"
+              exit 0
+            fi
+            # Only EXIT_LOW_COVERAGE (3) from the script advances to the next run
+            [ "${status}" -eq 3 ] || exit 1
+            echo "::warning::Run ${id} covers too few test files; trying the next"
+          done
+          echo "::error::No dev CI run with usable junit artifacts in range; the feed is starved"
+          exit 1
+
+      - name: Commit changes
+        uses: peter-evans/create-pull-request@5f6978faf089d4d20b00c7766989d076bb2fc7f1 # v8.1.1
+        with:
+          commit-message: "[ci] Refresh integration test durations"
+          committer: esphome[bot] <115708604+esphome[bot]@users.noreply.github.com>
+          author: esphome[bot] <115708604+esphome[bot]@users.noreply.github.com>
+          branch: sync/integration-durations
+          delete-branch: true
+          title: "[ci] Refresh integration test durations"
+          body-path: .github/PULL_REQUEST_TEMPLATE.md
+          token: ${{ steps.generate-token.outputs.token }}

.gitignore

@@ -133,8 +133,12 @@ CTestTestfile.cmake
 .gcc-flags.json
 
 config/
+# Test fixture config/ directories are tracked (the rule above is the dashboard dir)
+!tests/component_tests/**/config/
 tests/build/
 tests/.esphome/
+# Output kept by failing tests for inspection; uploaded by CI
+test_artifacts/
 /.temp-clang-tidy.cpp
 /.temp/
 .pio/

.pre-commit-config.yaml

@@ -1,7 +1,6 @@
 ---
 # See https://pre-commit.com for more information
 # See https://pre-commit.com/hooks.html for more hooks
-
 ci:
   autoupdate_commit_msg: 'pre-commit: autoupdate'
   autoupdate_schedule: off  # Disabled until ruff versions are synced between deps and pre-commit
@@ -11,7 +10,7 @@ ci:
 repos:
   - repo: https://github.com/astral-sh/ruff-pre-commit
     # Ruff version.
-    rev: v0.15.15
+    rev: v0.16.10
     hooks:
       # Run the linter.
       - id: ruff
@@ -19,7 +18,7 @@ repos:
       # Run the formatter.
       - id: ruff-format
   - repo: https://github.com/PyCQA/flake8
-    rev: 7.3.0
+    rev: 7.4.1
     hooks:
       - id: flake8
         additional_dependencies:
@@ -42,7 +41,7 @@ repos:
       - id: pyupgrade
         args: [--py312-plus]
   - repo: https://github.com/adrienverge/yamllint.git
-    rev: v1.37.1
+    rev: v1.38.0
     hooks:
       - id: yamllint
         exclude: ^(\.clang-format|\.clang-tidy)$

AGENTS.md

@@ -44,6 +44,16 @@ This document provides essential context for AI models interacting with this pro
 
 ## 4. Coding Conventions & Style Guide
 
+**Read the developer documentation before writing a component.** https://developers.esphome.io covers the
+component lifecycle, the main loop, and the reasoning behind the rules below in far more depth than this
+file does, and it is the authority when they disagree. The most useful starting points:
+
+*   https://developers.esphome.io/architecture/components/ - component lifecycle, `setup()`, `loop()`,
+    setup priorities, and how a component is registered.
+*   https://developers.esphome.io/architecture/components/advanced/ - choosing between `loop()`,
+    `set_interval`, `set_timeout` and `defer`; waking the loop from another thread; the RAM cost of each.
+*   https://developers.esphome.io/contributing/code/ - contribution rules, public API and breaking changes.
+
 *   **Formatting:**
     *   **Python:** Uses `ruff` and `flake8` for linting and formatting. Configuration is in `pyproject.toml`.
     *   **C++:** Uses `clang-format` for formatting. Configuration is in `.clang-format`.
@@ -57,6 +67,13 @@ This document provides essential context for AI models interacting with this pro
         - Function-local constants: `lower_snake_case`
         - Protected/private fields: `lower_snake_case_with_trailing_underscore_`
         - Favor descriptive names over abbreviations
+        - Device components are named brand plus model (`siemens_ira211`), without a protocol-family prefix
+        - Enumerator names: prefix every value of an `enum class` with the enum name converted to
+          `UPPER_SNAKE_CASE` (e.g. `UARTFlushResult::UART_FLUSH_RESULT_SUCCESS`). Never use bare
+          names like `SUCCESS`, `FAILURE`, `OK`, or `FAIL`: platform SDK headers define macros with
+          these common names (for example the Realtek SDKs used by LibreTiny define
+          `#define SUCCESS 0` in `basic_types.h`), and the preprocessor replaces the enumerator
+          before the compiler sees it, breaking the build and clang-tidy on those platforms.
 
 *   **Python Idioms:**
     *   **Assignment expressions (PEP 572):** Prefer the walrus operator (`:=`) wherever it removes a redundant lookup or a throwaway temporary. The most common case in component code is presence-checking a config key and then indexing it separately — fetch once with `.get()` and bind in the condition instead:
@@ -136,6 +153,83 @@ This document provides essential context for AI models interacting with this pro
     *   **Indentation:** Use spaces (two per indentation level), not tabs
     *   **Type aliases:** Prefer `using type_t = int;` over `typedef int type_t;`
     *   **Line length:** Wrap lines at no more than 120 characters
+    *   **Timing in `loop()`:** Never call `millis()` in a `loop()` body. The current tick's timestamp is
+        already cached - use `App.get_loop_component_start_time()` (from `esphome/core/application.h`).
+        Only reach for `millis()` when you genuinely need sub-tick resolution inside a long operation.
+    *   **The main loop runs every 16 ms.** A rate-limit gate shorter than that does nothing: the check
+        passes on essentially every pass of the loop, so it costs a comparison and buys nothing. Pick an
+        interval comfortably coarser than 16 ms, or drop the gate entirely and accept running every loop.
+        ```cpp
+        // Bad - a 10ms gate against a 16ms loop never holds anything back
+        static constexpr uint32_t POLL_INTERVAL_MS = 10;
+        const uint32_t now = millis();
+        if (now - this->last_poll_ < POLL_INTERVAL_MS)
+          return;
+        this->last_poll_ = now;
+        ```
+        ```cpp
+        // Good - an interval that actually rate limits, off the cached timestamp
+        static constexpr uint32_t POLL_INTERVAL_MS = 100;
+        const uint32_t now = App.get_loop_component_start_time();
+        if (now - this->last_poll_ < POLL_INTERVAL_MS)
+          return;
+        this->last_poll_ = now;
+        ```
+        Pick the primitive by cadence: under 250 ms use a gated `loop()`; 500 ms and above use
+        `set_interval`. Full reasoning, including why `set_interval` costs more below 500 ms:
+        https://developers.esphome.io/architecture/components/advanced/#quick-rule-of-thumb
+    *   **Repeating work:** use `set_interval`, never a `set_timeout` that re-arms itself; every re-arm
+        rebuilds the callback and re-queues a scheduler item, and the period drifts.
+    *   **Scheduler ids:** name a timer only when it must be cancelled or replaced, and use a
+        `static constexpr uint32_t` id, never a string. Ids are per component instance and cannot clash with other
+        components, so number them from 0 and keep all of a component's ids together in one place.
+        ```cpp
+        static constexpr uint32_t READ_TIMEOUT_ID = 0;
+        this->set_timeout(READ_TIMEOUT_ID, 50, [this]() { this->read_(); });
+        ```
+    *   **Don't override a default with the same value:** if a base class method already returns what you
+        want, do not override it. `Component::get_setup_priority()` returns `setup_priority::DATA`, so a
+        component that wants `DATA` should simply leave it alone.
+        ```cpp
+        // Bad - this is exactly what the base class already does
+        float get_setup_priority() const override { return setup_priority::DATA; }
+        ```
+    *   **Constant data lives in RAM on ESP8266** unless marked `PROGMEM`: `const` tables, class-scope
+        constant arrays, and in-class `std::array` initializers (a `.rodata` template plus a copy). Mark the
+        table `PROGMEM` and read it with `progmem_memcpy()` or `progmem_read_byte()` (`esphome/core/hal.h`);
+        for a table of structs copy the whole entry out and return the copy, never a pointer into flash.
+        On other platforms they are a plain `memcpy` and dereference, so no `#ifdef` is needed. Declare log tags with
+        `ESPHOME_LOG_TAG(TAG, "name")`, pass status text as `LOG_STR`, e.g.
+        `this->mark_failed(LOG_STR(ESP_LOG_MSG_COMM_FAIL))`, and give an action whose payload is a byte array
+        a `TEMPLATABLE_BYTES` field so a static code stays in flash.
+    *   **Fixed sets of names** (status words, model names): a `PROGMEM_STRING_TABLE` (`esphome/core/progmem.h`),
+        logged with `get_log_str` and `LOG_STR_ARG`, copied out with `ESPHOME_strncpy_P` before `publish_state`.
+        A `dump_config` helper that picks a name returns `const LogString *` from `LOG_STR(...)`.
+    *   **CRCs and bit tricks** come from `esphome/core/helpers.h` (`crc8`, `crc16`, `reverse_bits`, `encode_uint16`);
+        pick the helper's polynomial and bit-order arguments instead of writing a CRC loop.
+    *   **An unset float is `NAN`**, not `optional<float>`; the optional costs 4 to 8 bytes of padding per member.
+    *   **`PollingComponent` first runs `update()`** after a random share of the interval; call `this->update()` at the
+        end of `setup()` when the entities need a state at boot.
+    *   **A multi-step command sequence** leaves the step pending when the answer is malformed, so the existing
+        resend and give-up logic handles it; never advance on an answer that was only logged.
+    *   **Entities that each watch a register field:** one class taking register, shift, mask and match from a Python
+        tuple table, in typed `StaticVector`s sized by `cg.slot_counter`; not a template per bit, not a virtual
+        listener base (a second vptr per entity).
+    *   **A global feature define** says the code is compiled in, not that this instance uses it: keep the
+        per-instance check (`if (this->aux_device_ == ...)`) inside the `#ifdef`.
+    *   **Failures after `setup()`:** `mark_failed()` is for `setup()` only. A runtime read or write failure
+        sets `status_set_warning()` and the next success clears it; writes skip work when `is_failed()`.
+    *   **Fixed platform facts compile to nothing:** gate on `#ifdef USE_ESP8266` and friends, not on a
+        runtime check of something the build already knows.
+    *   **Logging string literals:** wrap literals passed as `%s` arguments in `LOG_STR_LITERAL()` so they
+        can be stored in flash rather than RAM.
+        ```cpp
+        // Bad
+        ESP_LOGV(TAG, "Key %u %s", key, pressed ? "pressed" : "released");
+
+        // Good
+        ESP_LOGV(TAG, "Key %u %s", key, pressed ? LOG_STR_LITERAL("pressed") : LOG_STR_LITERAL("released"));
+        ```
     *   **Constructor parameters vs setters:** Component properties that are both **required** and **invariant**
         (never change after construction) should be constructor parameters rather than set via setter methods.
         This makes the dependency explicit and prevents use of the object in an incompletely-initialized state.
@@ -173,6 +267,10 @@ This document provides essential context for AI models interacting with this pro
         ```
 
     *   **Component Metadata:**
+        - `DOMAIN`: Required in every component's `__init__.py`, set to the component's own name as a plain
+          string (e.g. `DOMAIN = "my_component"`). Other code refers to the component through it, e.g.
+          `from esphome.components.my_component import DOMAIN`. Keep it in alphabetical order with the other
+          metadata constants. CI (`lint_component_domain`) fails without it.
         - `DEPENDENCIES`: List of required components
         - `AUTO_LOAD`: Components to automatically load
         - `CONFLICTS_WITH`: Incompatible components
@@ -186,16 +284,20 @@ This document provides essential context for AI models interacting with this pro
         import esphome.config_validation as cv
         from esphome.const import CONF_KEY, CONF_ID
 
+        DOMAIN = "my_component"
         CONF_PARAM = "param"  # A constant that does not yet exist in esphome/const.py
 
         my_component_ns = cg.esphome_ns.namespace("my_component")
         MyComponent = my_component_ns.class_("MyComponent", cg.Component)
 
-        CONFIG_SCHEMA = cv.Schema({
-            cv.GenerateID(): cv.declare_id(MyComponent),
-            cv.Required(CONF_KEY): cv.string,
-            cv.Optional(CONF_PARAM, default=42): cv.int_,
-        }).extend(cv.COMPONENT_SCHEMA)
+        CONFIG_SCHEMA = cv.Schema(
+            {
+                cv.GenerateID(): cv.declare_id(MyComponent),
+                cv.Required(CONF_KEY): cv.string,
+                cv.Optional(CONF_PARAM, default=42): cv.int_,
+            }
+        ).extend(cv.COMPONENT_SCHEMA)
+
 
         async def to_code(config):
             var = cg.new_Pvariable(config[CONF_ID])
@@ -229,7 +331,12 @@ This document provides essential context for AI models interacting with this pro
         - **Sensor:**
           ```python
           from esphome.components import sensor
-          CONFIG_SCHEMA = sensor.sensor_schema(MySensor).extend(cv.polling_component_schema("60s"))
+
+          CONFIG_SCHEMA = sensor.sensor_schema(MySensor).extend(
+              cv.polling_component_schema("60s")
+          )
+
+
           async def to_code(config):
               var = await sensor.new_sensor(config)
               await cg.register_component(var, config)
@@ -238,7 +345,10 @@ This document provides essential context for AI models interacting with this pro
         - **Binary Sensor:**
           ```python
           from esphome.components import binary_sensor
-          CONFIG_SCHEMA = binary_sensor.binary_sensor_schema().extend({ ... })
+
+          CONFIG_SCHEMA = binary_sensor.binary_sensor_schema().extend({...})
+
+
           async def to_code(config):
               var = await binary_sensor.new_binary_sensor(config)
           ```
@@ -246,11 +356,33 @@ This document provides essential context for AI models interacting with this pro
         - **Switch:**
           ```python
           from esphome.components import switch
-          CONFIG_SCHEMA = switch.switch_schema().extend({ ... })
+
+          CONFIG_SCHEMA = switch.switch_schema().extend({...})
+
+
           async def to_code(config):
               var = await switch.new_switch(config)
           ```
 
+        - **Optional child entities of a hub:** bind the config once with `sensor.sub_sensors(config)` (or
+          `sub_binary_sensors`, `sub_text_sensors`, `sub_buttons`, `sub_switches`, `sub_numbers`,
+          `sub_selects` in their domains), adding `parent=hub` for entities that derive from `Parented<T>`,
+          then make one call per key, even when there is only one. A call creates the entity only when its key
+          is configured, passes it to the setter and returns it (or `None`); extra arguments such as
+          `min_value` or `options` go on the call. Always name the setter explicitly on the object that owns
+          it, never with `getattr` and an f-string, and keep that variable short (`var` for the component
+          itself, `hub` for one fetched with `cg.get_variable`) so the calls fit on one line. Loops whose
+          setter also takes an index, such as `set_gate_threshold(x, n)`, stay as they are.
+          ```python
+          async def to_code(config):
+              var = cg.new_Pvariable(config[CONF_ID])
+              sensors = sensor.sub_sensors(config)
+              await sensors(CONF_TEMPERATURE, var.set_temperature_sensor)
+              await sensors(CONF_HUMIDITY, var.set_humidity_sensor)
+              buttons = button.sub_buttons(config, parent=var)
+              await buttons(CONF_RESTART, var.set_restart_button)
+          ```
+
 *   **Automations (Triggers, Actions, Conditions):**
 
     Automations have three building blocks: **Triggers** (fire when something happens), **Actions** (do something), and **Conditions** (check if something is true).
@@ -263,10 +395,13 @@ This document provides essential context for AI models interacting with this pro
         ```python
         from esphome import automation
 
-        CONFIG_SCHEMA = cv.Schema({
-            cv.GenerateID(): cv.declare_id(MyComponent),
-            cv.Optional(CONF_ON_STATE): automation.validate_automation({}),
-        }).extend(cv.COMPONENT_SCHEMA)
+        CONFIG_SCHEMA = cv.Schema(
+            {
+                cv.GenerateID(): cv.declare_id(MyComponent),
+                cv.Optional(CONF_ON_STATE): automation.validate_automation({}),
+            }
+        ).extend(cv.COMPONENT_SCHEMA)
+
 
         async def to_code(config):
             var = cg.new_Pvariable(config[CONF_ID])
@@ -291,6 +426,25 @@ This document provides essential context for AI models interacting with this pro
                 )
         ```
 
+        When the callback's parameters differ from the automation's arguments, or the trigger should only
+        fire for some values, pass `params`, `forward` and `when`; the helper then generates a capture-less
+        lambda (stored inline, nothing allocated). Name the parent with `automation.parent_ref(var)` and build
+        `forward` from `MockObj` calls, not f-strings of C++:
+        ```python
+        parent = automation.parent_ref(var)
+        index = cg.RawExpression("index")
+        await automation.build_callback_automation(
+            var,
+            "add_on_state_callback",
+            [(cg.StringRef, "x"), (cg.size_t, "i")],
+            conf,
+            params=[(cg.size_t, "index")],
+            forward=[cg.StringRef(parent.option_at(index)), index],
+        )
+        ```
+        `build_parent_callback_automation`, `build_trigger_callback`, `build_callback_automations` and
+        `build_trigger_automations` cover the other shapes; see their docstrings in `esphome/automation.py`.
+
         **C++ -- no trigger class needed.** The callback registration method must be templatized to accept both `std::function` and lightweight forwarder structs (which avoid heap allocation):
         ```cpp
         class MyComponent : public Component {
@@ -316,11 +470,14 @@ This document provides essential context for AI models interacting with this pro
         ```python
         TurnOnTrigger = my_ns.class_("TurnOnTrigger", automation.Trigger.template())
 
-        CONFIG_SCHEMA = cv.Schema({
-            cv.Optional(CONF_ON_TURN_ON): automation.validate_automation(
-                {cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(TurnOnTrigger)}
-            ),
-        })
+        CONFIG_SCHEMA = cv.Schema(
+            {
+                cv.Optional(CONF_ON_TURN_ON): automation.validate_automation(
+                    {cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(TurnOnTrigger)}
+                ),
+            }
+        )
+
 
         async def to_code(config):
             for conf in config.get(CONF_ON_TURN_ON, []):
@@ -354,7 +511,31 @@ This document provides essential context for AI models interacting with this pro
           MyComponent *parent_;
         };
         ```
-        Register with `@automation.register_action("my_component.do_something", MyAction, schema, synchronous=True)`. Use `synchronous=True` for actions that run to completion inside `play()` without deferring. Use `synchronous=False` if the action may suspend/defer execution (e.g. `delay`, `wait_until`, `script.wait`) or store trigger arguments for later use.
+        Register it without writing a builder:
+        ```python
+        automation.register_simple_action(
+            "my_component.do_something", MyAction, schema, synchronous=True
+        )
+        ```
+        The constructor receives the object named by `config[CONF_ID]`. Use `register_bare_action` for a
+        no-argument constructor, `register_parented_action` for a class deriving from `Parented<T>`, and
+        the `@automation.register_action(...)` decorator only when the builder must also set fields.
+
+        Use `synchronous=True` for actions that run to completion inside `play()` without deferring. Use `synchronous=False` if the action may suspend/defer execution (e.g. `delay`, `wait_until`, `script.wait`) or store trigger arguments for later use.
+
+        **Actions that only forward templatable values to their parent need no C++ class.** Register them
+        with `register_apply_action`; do not write a `TEMPLATABLE_VALUE` class or a builder for this shape.
+        ```python
+        automation.register_apply_action(
+            "my_component.set_gains",
+            schema,
+            automation.ApplyField(CONF_KP, "set_kp", cg.float_),
+            automation.ApplyField(CONF_KI, "set_ki", cg.float_),
+        )
+        ```
+        The `ApplyField`, `ApplyCall` and `register_apply_action` docstrings in `esphome/automation.py` cover
+        the rest; `cover.control` and `cover.template.publish` are in-tree examples. `TEMPLATABLE_VALUE` with
+        `cg.templatable` stays for actions whose `play()` has real logic beyond forwarding values.
 
     *   **Conditions:**
         ```cpp
@@ -366,9 +547,27 @@ This document provides essential context for AI models interacting with this pro
           MyComponent *parent_;
         };
         ```
-        Register with `@automation.register_condition("my_component.is_active", MyCondition, schema)`.
+        Register with `automation.register_simple_condition("my_component.is_active", MyCondition, schema)`;
+        `register_bare_condition`, `register_parented_condition` and the decorator follow the action rules.
+
+        **Conditions that only test their parent need no C++ class either.** Register them with
+        `register_apply_condition`; the expression is applied to the parent, and an `ApplyCall` compares
+        against config values.
+        ```python
+        automation.register_apply_condition("my_component.is_active", schema, "is_active()")
+        automation.register_apply_condition(
+            "my_component.state_is",
+            schema,
+            automation.ApplyCall("state == {}", ((CONF_STATE, cg.bool_),)),
+        )
+        ```
+        `cover.is_open`, `rtttl.is_playing` and `component.is_idle` are in-tree examples.
+
+*   **Type Hints:** Type-hint all function signatures, including test functions and config validators (e.g. `def validate_x(config: ConfigType) -> ConfigType:`, `def test_x() -> None:`). Import `ConfigType` from `esphome.types`.
+    An intentionally empty body (an unused `register_dumper` builder, for example) gets a one-line docstring, not `pass`.
 
 *   **Configuration Validation:**
+    *   **Reuse existing validators:** Before writing a custom validator, check for an existing one in `config_validation.py` and compose it in `cv.All(...)` rather than duplicating logic across components. For example, rename a config key with `cv.rename_key(CONF_OLD, CONF_NEW, removed_in="2026.6.0")`, and reject mutually-exclusive keys with `cv.has_at_most_one_key(...)` / `cv.has_exactly_one_key(...)`. See how `api` composes `cv.has_exactly_one_key` + `cv.rename_key`.
     *   **Common Validators:** `cv.int_`, `cv.float_`, `cv.string`, `cv.boolean`, `cv.int_range(min=0, max=100)`, `cv.positive_int`, `cv.percentage`.
     *   **Complex Validation:** `cv.All(cv.string, cv.Length(min=1, max=50))`, `cv.Any(cv.int_, cv.string)`.
     *   **Platform-Specific:** `cv.only_on(["esp32", "esp8266"])`, `esp32.only_on_variant(...)`, `cv.only_on_esp32`, `cv.only_on_esp8266`, `cv.only_on_rp2040`.
@@ -381,6 +580,7 @@ This document provides essential context for AI models interacting with this pro
          .extend(i2c.i2c_device_schema(0x48))
          .extend(spi.spi_device_schema(cs_pin_required=True))
         ```
+    *   **Constants:** `esphome/const.py` is frozen — do not add new `CONF_` constants there. Define a component-local constant in the component's own `.py` (as with `CONF_PARAM` above); for a constant shared by multiple components, add it to `esphome/components/const/__init__.py`. CI (`lint_constants_usage`) fails if the same constant is defined in three or more component files. Constants used in core files (i.e. those not under `esphome/components`) may be added to `esphome/const.py` but will require adjustment to the CI validation check.
 
 ## 5. Key Files & Entrypoints
 
@@ -388,7 +588,7 @@ This document provides essential context for AI models interacting with this pro
 *   **Configuration:**
     *   `pyproject.toml`: Defines the Python project metadata and dependencies.
     *   `platformio.ini`: Configures the PlatformIO build environments for different microcontrollers.
-    *   `.pre-commit-config.yaml`: Configures the pre-commit hooks for linting and formatting.
+    *   `.pre-commit-config.yaml`: Configures the lint and format hooks, run by `prek`.
 *   **CI/CD Pipeline:** Defined in `.github/workflows`.
 *   **Static Analysis & Development:**
     *   `esphome/core/defines.h`: A comprehensive header file containing all `#define` directives that can be added by components using `cg.add_define()` in Python. This file is used exclusively for development, static analysis tools, and CI testing - it is not used during runtime compilation. When developing components that add new defines, they must be added to this file to ensure proper IDE support and static analysis coverage. The file includes feature flags, build configurations, and platform-specific defines that help static analyzers understand the complete codebase without needing to compile for specific platforms.
@@ -396,10 +596,19 @@ This document provides essential context for AI models interacting with this pro
 ## 6. Development & Testing Workflow
 
 *   **Local Development Environment:** Use the provided Docker container or create a Python virtual environment and install dependencies from `requirements_dev.txt`.
-*   **Running Commands:** Use the `script/run-in-env.py` script to execute commands within the project's virtual environment. For example, to run the linter: `python3 script/run-in-env.py pre-commit run`.
+*   **Running Commands:** Use the `script/run-in-env.py` script to execute commands within the project's virtual environment. For example, to run the linter: `python3 script/run-in-env.py prek run`.
 *   **Testing:**
     *   **Python:** Run unit tests with `pytest`.
     *   **C++:** Use `clang-tidy` for static analysis.
+    *   **C++ unit tests:** gtests in `tests/components/<component>/*.cpp`, run with
+        `script/cpp_unit_test.py <component>`; see `tests/components/README.md`. Set the loop clock in a test
+        with `LoopBlockingGuard{nullptr, nullptr, now_ms}`; the runner resets it before every test.
+    *   **Integration tests:** `tests/integration/` runs real firmware on the host. Serial components prove
+        timeouts and recovery with the `uart_mock` fixture (`tests/integration/test_uart_mock_*.py`). Its
+        `responses` match on content every time they see it; to answer a repeated request differently, use an
+        `on_tx` lambda with a static counter and `inject_to_rx_buffer` (see `uart_mock_ld2412_requery_after_giveup.yaml`).
+    *   **Keep build-test variants few:** one `test.<platform>.yaml` per platform the code actually differs
+        on. A variant per board for platform-identical code only adds CI time.
     *   **Component Tests:** YAML-based compilation tests are located in `tests/`. The structure is as follows:
         ```
         tests/
@@ -446,6 +655,7 @@ This document provides essential context for AI models interacting with this pro
             name: My Sensor
         ```
         Components that define buses directly are flagged as "NEEDS MIGRATION" and cannot be grouped, increasing CI build time.
+        `!extend` and `!remove` in a `test.*.yaml` also make the component ungroupable; add a standalone entity with its own id instead.
 
     *   **Testing All Components Together:** To verify that all components can be tested together without ID conflicts or configuration issues, use:
         ```bash
@@ -469,9 +679,10 @@ This document provides essential context for AI models interacting with this pro
     1.  **Fork & Branch:** Create a new branch based on the `dev` branch (always use `git checkout -b <branch-name> dev` to ensure you're branching from `dev`, not the currently checked out branch).
     2.  **Make Changes:** Adhere to all coding conventions and patterns.
     3.  **Test:** Create component tests for all supported platforms and run the full test suite locally.
-    4.  **Lint:** Run `pre-commit` to ensure code is compliant.
+    4.  **Lint:** Run `prek` to ensure code is compliant.
     5.  **Commit:** Commit your changes. There is no strict format for commit messages.
-    6.  **Pull Request:** Submit a PR against the `dev` branch. The Pull Request title should have a prefix of the component being worked on (e.g., `[display] Fix bug`, `[abc123] Add new component`). Update documentation, examples, and add `CODEOWNERS` entries as needed. Pull requests should always be made using the `.github/PULL_REQUEST_TEMPLATE.md` template - fill out all sections completely without removing any parts of the template.
+    6.  **Pull Request:** Submit a PR against the `dev` branch. The Pull Request title must start with a `[tag]` prefix. For component work, use the component name (e.g., `[display] Fix bug`, `[abc123] Add new component`); for changes to shared/core code that isn't tied to a single component, use `[core]` (e.g., `[core] Add validator`). Update documentation, examples, and add `CODEOWNERS` entries as needed. Pull requests should always be made using the `.github/PULL_REQUEST_TEMPLATE.md` template - fill out all sections completely without removing any parts of the template.
+    7.  **Comments:** When commenting on GitHub PRs or issues, don't tag contributors, especially bots. Avoid referring to list items (e.g. from reviews) with the form #nn - this will be interpreted by GitHub as a reference to issue or PR nn. Keep comments short and exclude irrelevant details, backstories, restatement of previous comments and anything that is already obvious to the reader.
 
 *   **Documentation Contributions:**
     *   Documentation is hosted in the separate `esphome/esphome.io` repository.
@@ -532,6 +743,36 @@ This document provides essential context for AI models interacting with this pro
            Use `cg.add_define("MAX_SERVICES", count)` to set the size from Python configuration.
            Like `std::array` but with vector-like API (`push_back()`, `size()`) and no STL reallocation code.
 
+           **Listener and child-entity registration lists are the most common case, and the most commonly
+           missed.** A `register_*()` method called once per child at code generation time has a count that
+           is known at compile time, so it should never be a `std::vector`. Use `cg.slot_counter()`: it
+           returns a function that each consumer calls once per slot it will occupy, and after every
+           `to_code` has run it emits the define with the final count. When nothing registers, no define is
+           emitted and the storage plus its registration method compile out entirely.
+           ```python
+           # hub component's __init__.py
+           _request_listener_slot = cg.slot_counter("MY_COMPONENT_LISTENER_COUNT")
+
+
+           async def register_listener(hub: MockObj, var: MockObj) -> None:
+               _request_listener_slot()
+               cg.add(hub.register_listener(var))
+           ```
+           When several instances each own a list declared at the same size (one per hub of a
+           `MULTI_CONF` component), pass the owning object as the key, `_request_listener_slot(str(hub))`;
+           the define is then the largest count any one key requested instead of the total.
+           ```cpp
+           #ifdef MY_COMPONENT_LISTENER_COUNT
+             void register_listener(MyComponentListener *listener);
+           #endif
+            protected:
+           #ifdef MY_COMPONENT_LISTENER_COUNT
+             StaticVector<MyComponentListener *, MY_COMPONENT_LISTENER_COUNT> listeners_;
+           #endif
+           ```
+           Request slots from `to_code`, not from a job that runs after `CoroPriority.FINAL` - a late
+           request raises rather than silently undercounting.
+
         3. **Runtime-known sizes:** Use `FixedVector` from `esphome/core/helpers.h` when the size is only known at runtime initialization.
            ```cpp
            // Bad - generates STL realloc code (_M_realloc_insert)
@@ -569,9 +810,27 @@ This document provides essential context for AI models interacting with this pro
            ```
            Linear search on small datasets (1-16 elements) is often faster than hashing/tree overhead, but this depends on lookup frequency and access patterns. For frequent lookups in hot code paths, the O(1) vs O(n) complexity difference may still matter even for small datasets. `std::vector` with simple structs is usually fine—it's the heavy containers (`map`, `set`, `unordered_map`) that should be avoided for small datasets unless profiling shows otherwise.
 
-        5. **Avoid `std::deque`:** It allocates in 512-byte blocks regardless of element size, guaranteeing at least 512 bytes of RAM usage immediately. This is a major source of crashes on memory-constrained devices.
+        5. **Strings set once from configuration:** Use `StringRef` (`esphome/core/string_ref.h`) rather than
+           `std::string`. Code generation passes a string literal that lives in flash for the life of the
+           program, so storing a `std::string` copies it onto the heap for nothing. `StringRef` is a
+           non-owning pointer plus length; it does not copy, and it must only ever refer to storage that
+           outlives it (a string literal, or a buffer owned elsewhere).
+           ```cpp
+           // Bad - heap copy of a literal that is already in flash
+           void set_keys(std::string keys) { this->keys_ = std::move(keys); }
+           std::string keys_;
+           ```
+           ```cpp
+           // Good - no allocation
+           void set_keys(const char *keys) { this->keys_ = StringRef(keys); }
+           StringRef keys_;
+           ```
 
-        6. **Detection:** Look for these patterns in compiler output:
+        6. **Avoid `std::deque`:** It allocates in 512-byte blocks regardless of element size, guaranteeing at least 512 bytes of RAM usage immediately. This is a major source of crashes on memory-constrained devices.
+
+        7. **Never use `new (std::nothrow)`:** On ESP-IDF exceptions are disabled, so a failed nothrow allocation aborts instead of returning `nullptr`. Use `RAMAllocator` from `esphome/core/helpers.h`; CI rejects `std::nothrow`.
+
+        8. **Detection:** Look for these patterns in compiler output:
            - Large code sections with STL symbols (vector, map, set)
            - `alloc`, `realloc`, `dealloc` in symbol names
            - `_M_realloc_insert`, `_M_default_append` (vector reallocation)
@@ -617,6 +876,7 @@ This document provides essential context for AI models interacting with this pro
         _component_state = []
         _use_feature = None
 
+
         def enable_feature():
             global _use_feature
             _use_feature = True
@@ -636,20 +896,24 @@ This document provides essential context for AI models interacting with this pro
 
         DOMAIN = "my_component"
 
+
         @dataclass
         class MyComponentData:
             feature_enabled: bool = False
             item_count: int = 0
             items: list[str] = field(default_factory=list)
 
+
         def _get_data() -> MyComponentData:
             if DOMAIN not in CORE.data:
                 CORE.data[DOMAIN] = MyComponentData()
             return CORE.data[DOMAIN]
 
+
         def request_feature() -> None:
             _get_data().feature_enabled = True
 
+
         def add_item(item: str) -> None:
             _get_data().items.append(item)
         ```
@@ -704,10 +968,22 @@ This document provides essential context for AI models interacting with this pro
     ```
 
 *   **Deprecation Pattern (Python):**
+    For a renamed config key, use the shared `cv.rename_key` validator with `removed_in` (and `component` for context) — it warns and auto-migrates:
+    ```python
+    CONFIG_SCHEMA = cv.All(
+        cv.rename_key(
+            CONF_OLD_KEY, CONF_NEW_KEY, removed_in="2026.6.0", component="my_component"
+        ),
+        cv.Schema({...}),
+    )
+    ```
+    For other deprecations, warn manually during validation:
     ```python
     # Remove before 2026.6.0
     if CONF_OLD_KEY in config:
-        _LOGGER.warning(f"'{CONF_OLD_KEY}' deprecated, use '{CONF_NEW_KEY}'. Removed in 2026.6.0")
+        _LOGGER.warning(
+            f"'{CONF_OLD_KEY}' deprecated, use '{CONF_NEW_KEY}'. Removed in 2026.6.0"
+        )
         config[CONF_NEW_KEY] = config.pop(CONF_OLD_KEY)  # Auto-migrate
     ```
 ## 9. English Language
@@ -716,3 +992,13 @@ The project uses English for non-code content. When drafting documentation, code
 PR descriptions, and similar text, avoid technical jargon. Instead, express concepts in plain English,
 using standard technical terms only when required. Ensure the text is readily comprehensible to a wide
 audience, including non-native English speakers.
+
+## 10. Code Comments
+
+Code comments on individual lines should be used only where necessary to flag issues that may not be obvious
+on a simple reading of the code. Keep them short (e.g. 1 or 2 lines).
+
+Function and method comment blocks may include more detail as required to make
+calling contracts clear and document parameter usage, but should still be kept concise.
+
+Avoid redundancy and repetition; comments should never simply restate what the code already says.

CODEOWNERS

@@ -39,9 +39,12 @@ esphome/components/am43/sensor/* @buxtronix
 esphome/components/analog_threshold/* @ianchi
 esphome/components/animation/* @syndlex
 esphome/components/anova/* @buxtronix
+esphome/components/apc1/* @ademuri
 esphome/components/apds9306/* @aodrenah
+esphome/components/apds9930/* @iyesin
 esphome/components/api/* @esphome/core
 esphome/components/aqi/* @freekode @jasstrong @ximex
+esphome/components/aranet/* @patrickod
 esphome/components/as5600/* @ammmze
 esphome/components/as5600/sensor/* @ammmze
 esphome/components/as7341/* @mrgnr
@@ -65,16 +68,21 @@ esphome/components/bedjet/climate/* @jhansche
 esphome/components/bedjet/fan/* @jhansche
 esphome/components/bedjet/sensor/* @javawizard @jhansche
 esphome/components/beken_spi_led_strip/* @Mat931
+esphome/components/bh1745/* @latonita
 esphome/components/bh1750/* @OttoWinter
 esphome/components/bh1900nux/* @B48D81EFCC
 esphome/components/binary_sensor/* @esphome/core
 esphome/components/bk72xx/* @kuba2k2
+esphome/components/bk72xx_ble/* @Bl00d-B0b
+esphome/components/bk72xx_ble_tracker/* @Bl00d-B0b
 esphome/components/bl0906/* @athom-tech @jesserockz @tarontop
 esphome/components/bl0939/* @ziceva
 esphome/components/bl0940/* @dan-s-github @tobias-
 esphome/components/bl0942/* @dbuezas @dwmw2
 esphome/components/ble_client/* @buxtronix @clydebarrow
+esphome/components/ble_device_base/* @Bl00d-B0b
 esphome/components/ble_nus/* @tomaszduda23
+esphome/components/bluetooth_connection/* @bdraco @jesserockz
 esphome/components/bluetooth_proxy/* @bdraco @jesserockz
 esphome/components/bm8563/* @abmantis
 esphome/components/bme280_base/* @esphome/core
@@ -96,6 +104,10 @@ esphome/components/bmp581_i2c/* @danielkent-net @kahrendt
 esphome/components/bmp581_spi/* @danielkent-net @kahrendt
 esphome/components/bp1658cj/* @Cossid
 esphome/components/bp5758d/* @Cossid
+esphome/components/bq25186/* @Rapsssito
+esphome/components/bq27220/* @rggammon
+esphome/components/bq76972/* @limpkin
+esphome/components/bridge/* @kbx81
 esphome/components/bthome_mithermometer/* @nagyrobi
 esphome/components/button/* @esphome/core
 esphome/components/bytebuffer/* @clydebarrow
@@ -107,6 +119,8 @@ esphome/components/captive_portal/* @esphome/core
 esphome/components/cc1101/* @gabest11 @lygris
 esphome/components/ccs811/* @habbie
 esphome/components/cd74hc4067/* @asoehlke
+esphome/components/cdc_acm_uart/* @kbx81
+esphome/components/cdc_acm_uart/bridge/* @kbx81
 esphome/components/ch422g/* @clydebarrow @jesterret
 esphome/components/ch423/* @dwmw2
 esphome/components/chsc6x/* @kkosik20
@@ -118,6 +132,7 @@ esphome/components/combination/* @Cat-Ion @kahrendt
 esphome/components/const/* @esphome/core
 esphome/components/coolix/* @glmnet
 esphome/components/copy/* @OttoWinter
+esphome/components/counter/* @clydebarrow
 esphome/components/cover/* @esphome/core
 esphome/components/cs5460a/* @balrog-kun
 esphome/components/cse7761/* @berfenger
@@ -127,6 +142,7 @@ esphome/components/cst816/* @clydebarrow
 esphome/components/cst9220/* @clydebarrow
 esphome/components/ct_clamp/* @jesserockz
 esphome/components/current_based/* @djwmarcx
+esphome/components/d01/* @ch604
 esphome/components/dac7678/* @NickB1
 esphome/components/daikin_arc/* @MagicBear
 esphome/components/daikin_brc/* @hagak
@@ -144,9 +160,13 @@ esphome/components/display_menu_base/* @numo68
 esphome/components/dlms_meter/* @latonita @PolarGoose @SimonFischer04 @Tomer27cz
 esphome/components/dps310/* @kbx81
 esphome/components/ds1307/* @badbadc0ffee
+esphome/components/ds1603l/* @JakeLC15
 esphome/components/ds2484/* @mrk-its
+esphome/components/ds248x/* @tomwellnitz
+esphome/components/ds3231/* @linkedupbits
 esphome/components/dsmr/* @glmnet @PolarGoose
 esphome/components/duty_time/* @dudanov
+esphome/components/ecocomfort2/* @gledian
 esphome/components/ee895/* @Stock-M
 esphome/components/ektf2232/touchscreen/* @jesserockz
 esphome/components/emc2101/* @ellull
@@ -172,24 +192,29 @@ esphome/components/esp32_camera_web_server/* @ayufan
 esphome/components/esp32_can/* @Sympatron
 esphome/components/esp32_hosted/* @swoboda1337
 esphome/components/esp32_hosted/update/* @swoboda1337
-esphome/components/esp32_improv/* @jesserockz
+esphome/components/esp32_power_management/* @rwrozelle
 esphome/components/esp32_rmt/* @jesserockz
 esphome/components/esp32_rmt_led_strip/* @jesserockz
 esphome/components/esp8266/* @esphome/core
 esphome/components/esp_ldo/* @clydebarrow
+esphome/components/espectre/* @francescopace
+esphome/components/esphome/ota/* @esphome/core
 esphome/components/espnow/* @jesserockz
 esphome/components/espnow/packet_transport/* @EasilyBoredEngineer
 esphome/components/ethernet_info/* @gtjadsonsantos
 esphome/components/event/* @nohat
+esphome/components/exponential_moving_average/* @clydebarrow
 esphome/components/exposure_notifications/* @OttoWinter
 esphome/components/ezo/* @ssieb
 esphome/components/ezo_pmp/* @carlos-sarmiento
+esphome/components/ezsp_proxy_tap/* @kbx81 @puddly
 esphome/components/factory_reset/* @anatoly-savchenkov
 esphome/components/fastled_base/* @OttoWinter
 esphome/components/feedback/* @ianchi
 esphome/components/file/* @esphome/core
 esphome/components/fingerprint_grow/* @alexborro @loongyh @OnFreund
 esphome/components/font/* @clydebarrow @esphome/core
+esphome/components/friedrich/* @rwrozelle
 esphome/components/fs3000/* @kahrendt
 esphome/components/ft5x06/* @clydebarrow
 esphome/components/ft63x6/* @gpambrozio
@@ -233,9 +258,13 @@ esphome/components/hlw8032/* @rici4kubicek
 esphome/components/hm3301/* @freekode
 esphome/components/hmac_md5/* @dwmw2
 esphome/components/hmac_sha256/* @dwmw2
+esphome/components/hoermann_hcp/* @zweckj
 esphome/components/homeassistant/* @esphome/core @OttoWinter
+esphome/components/homeassistant/button/* @jesserockz
 esphome/components/homeassistant/number/* @landonr
+esphome/components/homeassistant/select/* @jesserockz
 esphome/components/homeassistant/switch/* @Links2004
+esphome/components/homeassistant/text/* @jesserockz
 esphome/components/honeywell_hih_i2c/* @Benichou34
 esphome/components/honeywellabp/* @RubyBailey
 esphome/components/honeywellabp2_i2c/* @jpfaff
@@ -247,6 +276,7 @@ esphome/components/http_request/ota/* @oarcher
 esphome/components/http_request/update/* @jesserockz
 esphome/components/htu31d/* @betterengineering
 esphome/components/hub75/* @stuartparmenter
+esphome/components/husb238/* @latonita
 esphome/components/hydreon_rgxx/* @functionpointer
 esphome/components/hyt271/* @Philippe12
 esphome/components/i2c/* @esphome/core
@@ -254,9 +284,12 @@ esphome/components/i2c_device/* @gabest11
 esphome/components/i2s_audio/* @jesserockz
 esphome/components/i2s_audio/microphone/* @jesserockz
 esphome/components/i2s_audio/speaker/* @jesserockz @kahrendt
+esphome/components/i2s_clockless_led_strip/* @j9brown
 esphome/components/iaqcore/* @yozik04
+esphome/components/icnt86/* @danepowell
 esphome/components/ili9xxx/* @clydebarrow @nielsnl68
 esphome/components/improv_base/* @esphome/core
+esphome/components/improv_ble/* @jesserockz
 esphome/components/improv_serial/* @esphome/core
 esphome/components/ina226/* @latonita @Sergio303
 esphome/components/ina260/* @mreditor97
@@ -269,6 +302,7 @@ esphome/components/inkplate/* @jesserockz @JosipKuci
 esphome/components/integration/* @OttoWinter
 esphome/components/internal_temperature/* @Mat931
 esphome/components/interval/* @esphome/core
+esphome/components/ir_rf_base/* @bdraco @kbx81
 esphome/components/ir_rf_proxy/* @kbx81
 esphome/components/it8951/* @koosoli @limengdu @Passific
 esphome/components/jsn_sr04t/* @Mafus1
@@ -280,21 +314,31 @@ esphome/components/kuntze/* @ssieb
 esphome/components/lc709203f/* @ilikecake
 esphome/components/lcd_menu/* @numo68
 esphome/components/ld2410/* @regevbr @sebcaps
+esphome/components/ld2410s/* @NovakIrs
 esphome/components/ld2412/* @Rihan9
 esphome/components/ld2420/* @descipher
 esphome/components/ld2450/* @hareeshmu
+esphome/components/ld2460/* @jesusvallejo
 esphome/components/ld24xx/* @kbx81
+esphome/components/ld6002b/* @hepter
 esphome/components/ledc/* @OttoWinter
 esphome/components/libretiny/* @kuba2k2
 esphome/components/libretiny_pwm/* @kuba2k2
 esphome/components/light/* @esphome/core
 esphome/components/lightwaverf/* @max246
 esphome/components/lilygo_t5_47/touchscreen/* @jesserockz
+esphome/components/lis2dw12/* @latonita
+esphome/components/lis2dw12_i2c/* @latonita
+esphome/components/lis2dw12_spi/* @latonita
+esphome/components/lis3dh/* @zebble
 esphome/components/lm75b/* @beormund
+esphome/components/ln882h_ble/* @Bl00d-B0b
+esphome/components/ln882h_ble_tracker/* @Bl00d-B0b
 esphome/components/ln882x/* @lamauny
 esphome/components/lock/* @esphome/core
 esphome/components/logger/* @esphome/core
 esphome/components/logger/select/* @clydebarrow
+esphome/components/lp5562/* @DennisGaida
 esphome/components/lps22/* @nagisa
 esphome/components/lsm6ds/* @clydebarrow
 esphome/components/ltr390/* @latonita @sjtrny
@@ -305,7 +349,9 @@ esphome/components/m5stack_8angle/* @rnauber
 esphome/components/mapping/* @clydebarrow
 esphome/components/matrix_keypad/* @ssieb
 esphome/components/max17043/* @blacknell
+esphome/components/max17048/* @B48D81EFCC
 esphome/components/max31865/* @DAVe3283
+esphome/components/max31888/* @JiriPrchal
 esphome/components/max44009/* @berfenger
 esphome/components/max6956/* @looping40
 esphome/components/max7219digit/* @rspaargaren
@@ -324,7 +370,6 @@ esphome/components/mcp4461/* @p1ngb4ck
 esphome/components/mcp4728/* @berfenger
 esphome/components/mcp47a1/* @jesserockz
 esphome/components/mcp9600/* @mreditor97
-esphome/components/mcp9808/* @k7hpn
 esphome/components/md5/* @esphome/core
 esphome/components/mdns/* @esphome/core
 esphome/components/media_player/* @jesserockz
@@ -338,13 +383,16 @@ esphome/components/midea_ir/* @dudanov
 esphome/components/mipi_dsi/* @clydebarrow
 esphome/components/mipi_rgb/* @clydebarrow
 esphome/components/mipi_spi/* @clydebarrow
+esphome/components/mistral_ir/* @lerhum
 esphome/components/mitsubishi/* @RubyBailey
 esphome/components/mitsubishi_cn105/* @crnjan
 esphome/components/mixer/speaker/* @kahrendt
+esphome/components/mk2pvrouter/* @FredM67
 esphome/components/mlx90393/* @functionpointer
 esphome/components/mlx90614/* @jesserockz
 esphome/components/mmc5603/* @benhoff
 esphome/components/mmc5983/* @agoode
+esphome/components/modbus_client/* @exciton
 esphome/components/modbus_controller/* @martgras
 esphome/components/modbus_controller/binary_sensor/* @martgras
 esphome/components/modbus_controller/number/* @martgras
@@ -371,8 +419,11 @@ esphome/components/nextion/switch/* @senexcrenshaw
 esphome/components/nextion/text_sensor/* @senexcrenshaw
 esphome/components/nfc/* @jesserockz @kbx81
 esphome/components/noblex/* @AGalfra
+esphome/components/noise/* @esphome/core
 esphome/components/npi19/* @bakerkj
 esphome/components/nrf52/* @tomaszduda23
+esphome/components/ns2009/* @tchilov
+esphome/components/ns2009/touchscreen/* @tchilov
 esphome/components/number/* @esphome/core
 esphome/components/one_wire/* @ssieb
 esphome/components/online_image/* @clydebarrow @guillempages
@@ -387,6 +438,7 @@ esphome/components/pca9554/* @bdraco @clydebarrow @hwstar
 esphome/components/pcf85063/* @brogon
 esphome/components/pcf8563/* @KoenBreeman
 esphome/components/pcm5122/* @remcom
+esphome/components/pd_pioneer_ir/* @martinsah
 esphome/components/pi4ioe5v6408/* @jesserockz
 esphome/components/pid/* @OttoWinter
 esphome/components/pipsolar/* @andreashergert1984
@@ -404,6 +456,8 @@ esphome/components/pn7150_i2c/* @jesserockz @kbx81
 esphome/components/pn7160/* @jesserockz @kbx81
 esphome/components/pn7160_i2c/* @jesserockz @kbx81
 esphome/components/pn7160_spi/* @jesserockz @kbx81
+esphome/components/pn71xx/* @jesserockz @kbx81
+esphome/components/power_management/* @rwrozelle
 esphome/components/power_supply/* @esphome/core
 esphome/components/preferences/* @esphome/core
 esphome/components/provisioning/* @esphome/core
@@ -411,6 +465,7 @@ esphome/components/psram/* @esphome/core
 esphome/components/pulse_meter/* @cstaahl @stevebaxter @TrentHouliston
 esphome/components/pvvx_mithermometer/* @pasiz
 esphome/components/pylontech/* @functionpointer
+esphome/components/pzem6l24/* @nuttytree
 esphome/components/qmi8658/* @clydebarrow
 esphome/components/qmp6988/* @andrewpc
 esphome/components/qr_code/* @wjtje
@@ -423,6 +478,8 @@ esphome/components/rc522/* @glmnet
 esphome/components/rc522_i2c/* @glmnet
 esphome/components/rc522_spi/* @glmnet
 esphome/components/rd03d/* @jasstrong
+esphome/components/remko_ar715/* @naKruul
+esphome/components/renogy_inverter_ble/* @emilioaray-dev
 esphome/components/resampler/speaker/* @kahrendt
 esphome/components/restart/* @esphome/core
 esphome/components/rf_bridge/* @jesserockz
@@ -433,13 +490,16 @@ esphome/components/rp2/* @jesserockz
 esphome/components/rp2040_ble/* @bdraco
 esphome/components/rp2040_pio_led_strip/* @Papa-DMan
 esphome/components/rp2040_pwm/* @jesserockz
+esphome/components/rp2_ble_tracker/* @bdraco
 esphome/components/rpi_dpi_rgb/* @clydebarrow
 esphome/components/rtl87xx/* @kuba2k2
 esphome/components/rtttl/* @glmnet @ximex
 esphome/components/runtime_image/* @clydebarrow @guillempages @kahrendt
 esphome/components/runtime_stats/* @bdraco
+esphome/components/rx8025t/* @remcom
 esphome/components/rx8130/* @beormund
 esphome/components/safe_mode/* @jsuanet @kbx81 @paulmonigatti
+esphome/components/samsung/* @jorofi
 esphome/components/scd4x/* @martgras @sjtrny
 esphome/components/script/* @esphome/core
 esphome/components/sdl/* @bdm310 @clydebarrow
@@ -455,21 +515,27 @@ esphome/components/sen21231/* @shreyaskarnik
 esphome/components/sen5x/* @martgras
 esphome/components/sen6x/* @martgras @mebner86 @tuct
 esphome/components/sendspin/* @kahrendt
+esphome/components/sendspin/image/* @kahrendt
 esphome/components/sendspin/media_player/* @kahrendt
 esphome/components/sendspin/media_source/* @kahrendt
 esphome/components/sendspin/sensor/* @kahrendt
+esphome/components/sendspin/switch/* @kahrendt
 esphome/components/sendspin/text_sensor/* @kahrendt
 esphome/components/sensirion_common/* @martgras
 esphome/components/sensor/* @esphome/core
 esphome/components/serial_proxy/* @kbx81
 esphome/components/sfa30/* @ghsensdev
+esphome/components/sfa40/* @NoQuarrel
 esphome/components/sgp40/* @SenexCrenshaw
 esphome/components/sgp4x/* @martgras @SenexCrenshaw
+esphome/components/sh1122_base/* @pl4nkton
+esphome/components/sh1122_spi/* @pl4nkton
 esphome/components/sha256/* @esphome/core
 esphome/components/shelly_dimmer/* @edge90 @rnauber
 esphome/components/sht3xd/* @mrtoy-me
 esphome/components/sht4x/* @sjtrny
 esphome/components/shutdown/* @esphome/core @jsuanet
+esphome/components/siemens_ira211/* @fonix232
 esphome/components/sigma_delta_output/* @Cat-Ion
 esphome/components/sim800l/* @glmnet
 esphome/components/sm10bit_base/* @Cossid
@@ -479,12 +545,14 @@ esphome/components/sm2335/* @Cossid
 esphome/components/sml/* @alengwenus
 esphome/components/smt100/* @piechade
 esphome/components/sn74hc165/* @jesserockz
+esphome/components/snapshot/* @clydebarrow
 esphome/components/socket/* @esphome/core
 esphome/components/sonoff_d1/* @anatoly-savchenkov
 esphome/components/sound_level/* @kahrendt
 esphome/components/spa06_base/* @danielkent-net
 esphome/components/spa06_i2c/* @danielkent-net
 esphome/components/spa06_spi/* @danielkent-net
+esphome/components/spd2010/* @grischard
 esphome/components/speaker/* @jesserockz @kahrendt
 esphome/components/speaker/media_player/* @kahrendt @synesthesiam
 esphome/components/speaker_source/* @kahrendt
@@ -514,6 +582,7 @@ esphome/components/st7735/* @SenexCrenshaw
 esphome/components/st7789v/* @kbx81
 esphome/components/st7920/* @marsjan155
 esphome/components/statsd/* @Links2004
+esphome/components/stcc4/* @j9brown
 esphome/components/stts22h/* @B48D81EFCC
 esphome/components/substitutions/* @esphome/core
 esphome/components/sun/* @OttoWinter
@@ -524,29 +593,38 @@ esphome/components/sx126x/* @swoboda1337
 esphome/components/sx127x/* @swoboda1337
 esphome/components/sy6970/* @linkedupbits
 esphome/components/syslog/* @clydebarrow
+esphome/components/systa_bus/* @Mat931
 esphome/components/t6615/* @tylermenezes
+esphome/components/tas2780/* @remcom
+esphome/components/tas58xx/* @mrtoy-me @remcom
 esphome/components/tc74/* @sethgirvan
+esphome/components/tca8418/* @zebble
 esphome/components/tca9548a/* @andreashergert1984
 esphome/components/tca9555/* @mobrembski
 esphome/components/tcl112/* @glmnet
+esphome/components/tcp_uart/* @Bascht74
 esphome/components/tee501/* @Stock-M
-esphome/components/teleinfo/* @0hax
+esphome/components/teleinfo/* @0hax @FredM67
 esphome/components/tem3200/* @bakerkj
 esphome/components/template/alarm_control_panel/* @grahambrown11 @hwstar
 esphome/components/template/datetime/* @rfdarter
 esphome/components/template/event/* @nohat
 esphome/components/template/fan/* @ssieb
 esphome/components/text/* @mauritskorse
+esphome/components/tfluna/* @candrews
 esphome/components/thermopro_ble/* @sittner
 esphome/components/thermostat/* @kbx81
 esphome/components/time/* @esphome/core
 esphome/components/tinyusb/* @kbx81
+esphome/components/tinyusb_keyboard/* @frederikbolding
 esphome/components/tlc5947/* @rnauber
 esphome/components/tlc5971/* @IJIJI
 esphome/components/tm1621/* @Philippe12
 esphome/components/tm1637/* @glmnet
 esphome/components/tm1638/* @skykingjwc
 esphome/components/tm1651/* @mrtoy-me
+esphome/components/tmc2209/* @remcom
+esphome/components/tmc22xx/* @remcom
 esphome/components/tmp102/* @timsavage
 esphome/components/tmp1075/* @sybrenstuvel
 esphome/components/tmp117/* @Azimath
@@ -563,15 +641,19 @@ esphome/components/tuya/select/* @bearpawmaxim
 esphome/components/tuya/sensor/* @jesserockz
 esphome/components/tuya/switch/* @jesserockz
 esphome/components/tuya/text_sensor/* @dentra
+esphome/components/tuya/water_heater/* @iago-veiga
 esphome/components/uart/* @esphome/core
 esphome/components/uart/button/* @ssieb
 esphome/components/uart/event/* @eoasmxd
 esphome/components/uart/packet_transport/* @clydebarrow
+esphome/components/uart_mux/* @kbx81
+esphome/components/uart_tcp/* @Bascht74
 esphome/components/udp/* @clydebarrow
 esphome/components/ufire_ec/* @pvizeli
 esphome/components/ufire_ise/* @pvizeli
 esphome/components/ufm01/* @ljungqvist
 esphome/components/ultrasonic/* @ssieb @swoboda1337
+esphome/components/unicode/* @esphome/core
 esphome/components/update/* @jesserockz
 esphome/components/uponor_smatrix/* @kroimon
 esphome/components/usb_cdc_acm/* @kbx81
@@ -594,7 +676,7 @@ esphome/components/web_server_idf/* @dentra
 esphome/components/weikai/* @DrCoolZic
 esphome/components/weikai_i2c/* @DrCoolZic
 esphome/components/weikai_spi/* @DrCoolZic
-esphome/components/whirlpool/* @glmnet
+esphome/components/whirlpool/* @arpena @glmnet
 esphome/components/whynter/* @aeonsablaze
 esphome/components/wiegand/* @ssieb
 esphome/components/wireguard/* @droscy @lhoracek @thomas0bernard
@@ -611,9 +693,11 @@ esphome/components/wts01/* @alepee
 esphome/components/x9c/* @EtienneMD
 esphome/components/xdb401/* @RT530
 esphome/components/xgzp68xx/* @gcormier
+esphome/components/xiaomi_body_scale/* @dckiller51
 esphome/components/xiaomi_hhccjcy10/* @fariouche
 esphome/components/xiaomi_lywsd02mmc/* @juanluss31
 esphome/components/xiaomi_lywsd03mmc/* @ahpohl
+esphome/components/xiaomi_mccgq02hl/* @ahpohl @morph027
 esphome/components/xiaomi_mhoc303/* @drug123
 esphome/components/xiaomi_mhoc401/* @vevsvevs
 esphome/components/xiaomi_rtcgq02lm/* @jesserockz
@@ -623,6 +707,7 @@ esphome/components/xpt2046/touchscreen/* @nielsnl68 @numo68
 esphome/components/xxtea/* @clydebarrow
 esphome/components/zephyr/* @tomaszduda23
 esphome/components/zephyr_mcumgr/ota/* @tomaszduda23
+esphome/components/zephyr_pwm/* @wiomoc
 esphome/components/zhlt01/* @cfeenstra1024
 esphome/components/zigbee/* @luar123 @tomaszduda23
 esphome/components/zio_ultrasonic/* @kahrendt

Doxyfile

@@ -48,7 +48,7 @@ PROJECT_NAME           = ESPHome
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 2026.7.2
+PROJECT_NUMBER         = 2026.11.0-dev
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a

THREAT_MODEL.md

@@ -23,7 +23,8 @@ For this repository there are two trusted inputs by design:
 1. **The configuration.** Anyone who can supply or edit a YAML config is trusted
    (see below).
 2. **Authenticated peers of a running device** — clients holding the device's
-   API encryption key / password, OTA password, or web server credentials.
+   API/OTA encryption key, API password, OTA password, or web server
+   credentials.
 
 The security boundary is therefore **unauthenticated network traffic vs. those
 trusted inputs.** A bug that lets an unauthenticated attacker cross it is a
@@ -76,8 +77,8 @@ These *are* security bugs in this repo, and we want to hear about them privately
   captive portal, etc.) **without** valid credentials.
 - Authentication or encryption bypass on the device — reaching API calls, OTA
   updates, or the web server without the configured key/password.
-- Flaws that weaken the device's API encryption (Noise), OTA, or web server auth
-  below their documented guarantees.
+- Flaws that weaken the device's API or OTA encryption (Noise), OTA auth, or
+  web server auth below their documented guarantees.
 
 ## The web server is an open HTTP API by design
 
@@ -121,6 +122,54 @@ and any memory-safety or protocol bug in the server reachable without credential
 This section documents the current design and scope; it is not a judgment that the
 design is optimal or that it will not change.
 
+## OTA update encryption
+
+The `esphome` OTA platform optionally encrypts updates with the same Noise
+`NNpsk0` pattern the native API uses; one key protects the device. A device
+whose `api:` block has an encryption key, static in the YAML or provisioned at
+runtime, compiles in the transport and offers it on every OTA connection once
+it holds a key, so an uploader presenting that key gets the guarantees below
+even without an `ota: encryption:` block; only that block makes the device
+require encryption. The guarantees are: the firmware image is confidential in
+transit, the uploader is authenticated by the pre-shared key, and the plaintext
+negotiation preceding the handshake is bound into the handshake prologue, so
+stripping or tampering with it fails the first MAC. With `ota: encryption:`
+configured both ends fail closed with no override: the device refuses
+plaintext uploads, and the CLI refuses to send plaintext when a key is
+configured. Without that block the CLI tries a static api key when the device
+offers and, until 2027.3.0, falls back to plaintext with a warning when the
+offer is missing or the handshake fails; a runtime provisioned key never
+reaches the CLI, so those uploads stay plaintext.
+
+Defeating any of that without the key is in scope: a device that requires
+encryption accepting a plaintext or downgraded upload, getting past the MAC,
+or recovering image contents from captured traffic.
+
+The following are **not** vulnerabilities, by design:
+
+- Plaintext OTA on a device with no `ota: encryption:` block, including one
+  that offers encryption because it has an api key. That is the documented
+  default, authenticated (if at all) by the OTA password. An uploader that
+  takes the offer skips the password; the key authenticates it. With a
+  runtime provisioned key and no `provisioning:` window, whoever provisions
+  the key gains that upload path too; validation warns about the pair.
+- The CLI plaintext fallback until 2027.3.0: without `ota: encryption:` an
+  active attacker who strips the offer or breaks the handshake can make a
+  keyed CLI upload plaintext, with the pre-existing plaintext exposure. A
+  device that requires encryption still refuses that upload.
+- The enablement window: firmware built with a static api key already offers
+  encryption, so turning on `ota: encryption:` is itself an encrypted upload.
+  Older firmware needs one last plaintext upload of an offering build, with
+  the pre-existing plaintext exposure.
+- The web OTA `/update` endpoint alongside encryption. With the `web_server`
+  or `prometheus` component the shared listener is always up, so the endpoint
+  stays reachable and validation warns about that combination;
+  `captive_portal:` alone brings the listener up only for the fallback AP
+  window, which is the intended recovery path, so that is not warned about.
+- CLI retry behavior on transport or MAC failures; every attempt renegotiates
+  a fresh handshake with fresh ephemerals, so retrying does not weaken
+  authentication.
+
 ## Explicitly out of scope
 
 - Local attackers who already have shell access on the host that runs `esphome`.

docker/Dockerfile

@@ -22,16 +22,13 @@ RUN \
     -r /requirements.txt
 
 # Install the ESPHome Device Builder dashboard.
-RUN uv pip install --no-cache-dir esphome-device-builder==1.6.9
+RUN uv pip install --no-cache-dir esphome-device-builder==1.23.1
 
 RUN \
     platformio settings set enable_telemetry No \
     && platformio settings set check_platformio_interval 1000000 \
     && mkdir -p /piolibs
 
-COPY script/platformio_install_deps.py platformio.ini /
-RUN /platformio_install_deps.py /platformio.ini --libraries
-
 ARG BUILD_VERSION
 
 LABEL \

docker/docker_entrypoint.sh

@@ -21,10 +21,14 @@ export PLATFORMIO_PLATFORMS_DIR="${pio_cache_base}/platforms"
 export PLATFORMIO_PACKAGES_DIR="${pio_cache_base}/packages"
 export PLATFORMIO_CACHE_DIR="${pio_cache_base}/cache"
 
-# Keep the native toolchain installs on the persistent cache root, not the
-# container's ephemeral user cache dir (re-downloaded on every restart).
+# Keep the native toolchain installs and compiler caches on the persistent
+# cache root, not the container's user cache dir: it is lost on every
+# restart, and not writable when the container runs as a non-root user.
 export ESPHOME_ESP_IDF_PREFIX="$(dirname "${pio_cache_base}")/idf"
 export ESPHOME_SDK_NRF_PREFIX="$(dirname "${pio_cache_base}")/sdk-nrf"
+export ESPHOME_ARDUINO8266_PREFIX="$(dirname "${pio_cache_base}")/arduino8266"
+export ESPHOME_HOST_PREFIX="$(dirname "${pio_cache_base}")/host"
+export ESPHOME_PLATFORMIO_CCACHE_DIR="$(dirname "${pio_cache_base}")/platformio-ccache"
 
 # If /build is mounted, use that as the build path
 # otherwise use path in /config (so that builds aren't lost on container restart)

docker/generate_tags.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 import argparse
+import os
 import re
 
 CHANNEL_DEV = "dev"
@@ -64,7 +65,10 @@ def main():
 
     suffix = f"-{args.suffix}" if args.suffix else ""
 
-    image_name = f"esphome/esphome{suffix}"
+    repository = (
+        (os.environ.get("GITHUB_REPOSITORY") or "esphome/esphome").strip().lower()
+    )
+    image_name = f"{repository}{suffix}"
 
     print(f"channel={channel}")
 

docker/ha-addon-rootfs/etc/s6-overlay/s6-rc.d/discovery/run

@@ -4,7 +4,6 @@
 # Home Assistant Add-on: ESPHome
 # Sends discovery information to Home Assistant.
 # ==============================================================================
-declare config
 declare port
 
 # We only disable it when disabled explicitly
@@ -19,14 +18,17 @@ port=$(bashio::addon.ingress_port)
 # Wait for the ESPHome Device Builder to become available
 bashio::net.wait_for "${port}" "127.0.0.1" 300
 
-config=$(\
-    bashio::var.json \
-        host "127.0.0.1" \
-        port "^${port}" \
-)
+# Send one discovery message; the config is a JSON string built with bashio::var.json.
+send_discovery() {
+    local service=$1
+    local config=$2
+    if bashio::discovery "${service}" "${config}" > /dev/null; then
+        bashio::log.info "Successfully send ${service} discovery information to Home Assistant."
+    else
+        bashio::log.error "${service} discovery message to Home Assistant failed!"
+    fi
+}
 
-if bashio::discovery "esphome" "${config}" > /dev/null; then
-    bashio::log.info "Successfully send discovery information to Home Assistant."
-else
-    bashio::log.error "Discovery message to Home Assistant failed!"
-fi
+send_discovery "esphome" "$(bashio::var.json host "127.0.0.1" port "^${port}")"
+# The Device Builder MCP server, consumed by Home Assistant's mcp integration.
+send_discovery "mcp" "$(bashio::var.json url "http://127.0.0.1:${port}/api/mcp")"

docker/ha-addon-rootfs/etc/s6-overlay/s6-rc.d/esphome/run

@@ -15,10 +15,14 @@ export PLATFORMIO_PLATFORMS_DIR="${pio_cache_base}/platforms"
 export PLATFORMIO_PACKAGES_DIR="${pio_cache_base}/packages"
 export PLATFORMIO_CACHE_DIR="${pio_cache_base}/cache"
 
-# Keep the native toolchain installs on the persistent /data volume, not the
-# container's ephemeral user cache dir (wiped on every add-on update/restart).
+# Keep the native toolchain installs and compiler caches on the persistent
+# /data volume, not the container's ephemeral user cache dir (wiped on every
+# add-on update/restart).
 export ESPHOME_ESP_IDF_PREFIX=/data/cache/idf
 export ESPHOME_SDK_NRF_PREFIX=/data/cache/sdk-nrf
+export ESPHOME_ARDUINO8266_PREFIX=/data/cache/arduino8266
+export ESPHOME_HOST_PREFIX=/data/cache/host
+export ESPHOME_PLATFORMIO_CCACHE_DIR=/data/cache/platformio-ccache
 
 if bashio::config.true 'leave_front_door_open'; then
     export DISABLE_HA_AUTHENTICATION=true

docker/test_configs/bk72xx-arduino.yaml

@@ -5,3 +5,15 @@ bk72xx:
   board: generic-bk7231n-qfn32-tuya
 
 logger:
+
+wifi:
+  ssid: MySSID
+  password: password1
+  ap:
+
+# mqtt and captive_portal together pull in AsyncTCP and ESPAsyncWebServer;
+# a stray ESP32 AsyncTCP copy on the library search path breaks this build
+captive_portal:
+
+mqtt:
+  broker: 192.168.178.84

docker/test_configs/esp8266-arduino-native.yaml

@@ -0,0 +1,8 @@
+esphome:
+  name: docker-test-esp8266-native
+
+esp8266:
+  board: d1_mini
+  toolchain: arduino
+
+logger:

docker/test_configs/esp8266-arduino.yaml

@@ -3,5 +3,7 @@ esphome:
 
 esp8266:
   board: d1_mini
+  # The PlatformIO path stays covered whatever the default is
+  toolchain: platformio
 
 logger:

esphome/address_cache.py

@@ -148,6 +148,13 @@ class AddressCache:
                 continue
             hostname, ips = arg.split("=", 1)
             # Normalize hostname for consistent lookups
-            normalized = normalize_hostname(hostname)
-            cache[normalized] = [ip.strip() for ip in ips.split(",")]
+            normalized = normalize_hostname(hostname.strip())
+            addresses = [ip for value in ips.split(",") if (ip := value.strip())]
+            if not normalized or not addresses:
+                _LOGGER.warning(
+                    "Invalid cache entry: %s (hostname and at least one address are required)",
+                    arg,
+                )
+                continue
+            cache[normalized] = addresses
         return cache

esphome/analyze_memory/cli.py

@@ -20,6 +20,7 @@ from . import (
     RAM_SECTIONS,
     MemoryAnalyzer,
 )
+from .toolchain import find_elf_path, find_idedata_path, idedata_candidates
 
 if TYPE_CHECKING:
     from . import ComponentMemory
@@ -759,45 +760,25 @@ def main():
         print(f"Error: {build_path} is not a directory", file=sys.stderr)
         sys.exit(1)
 
-    # Find firmware.elf
-    elf_file = None
-    for elf_candidate in [
-        build_path / "firmware.elf",
-        build_path / ".pioenvs" / build_path.name / "firmware.elf",
-    ]:
-        if elf_candidate.exists():
-            elf_file = str(elf_candidate)
-            break
-
-    if not elf_file:
-        print(f"Error: firmware.elf not found in {build_dir}", file=sys.stderr)
+    elf_path = find_elf_path(build_path)
+    if not elf_path:
+        print(f"Error: no firmware ELF found in {build_dir}", file=sys.stderr)
         sys.exit(1)
-
-    # Find idedata.json - check current directory first, then home
-    device_name = build_path.name
-    idedata_candidates = [
-        Path.cwd() / ".esphome" / "idedata" / f"{device_name}.json",
-        Path.home() / ".esphome" / "idedata" / f"{device_name}.json",
-    ]
+    elf_file = str(elf_path)
 
     idedata = None
-    for idedata_path in idedata_candidates:
-        if not idedata_path.exists():
-            continue
+    if idedata_path := find_idedata_path(build_path):
         try:
             with idedata_path.open(encoding="utf-8") as f:
                 raw_data = json.load(f)
             idedata = IDEData(raw_data)
             print(f"Loaded idedata from: {idedata_path}", file=sys.stderr)
-            break
         except (json.JSONDecodeError, OSError) as e:
             print(f"Warning: Failed to load idedata: {e}", file=sys.stderr)
 
     if not idedata:
-        print(
-            f"Warning: idedata not found (searched {idedata_candidates[0]} and {idedata_candidates[1]})",
-            file=sys.stderr,
-        )
+        searched = "\n  ".join(str(p) for p in idedata_candidates(build_path))
+        print(f"Warning: idedata not found, searched:\n  {searched}", file=sys.stderr)
 
     analyzer = MemoryAnalyzerCLI(elf_file, idedata=idedata)
     analyzer.analyze()

esphome/analyze_memory/toolchain.py

@@ -23,6 +23,82 @@ TOOLCHAIN_PREFIXES = [
 ]
 
 
+def find_elf_path(build_path: Path) -> Path | None:
+    """Locate the firmware ELF inside an ESPHome build directory.
+
+    The layout depends on the toolchain that produced the build, so try each
+    known one in turn.
+
+    Args:
+        build_path: Path to an ESPHome build directory
+
+    Returns:
+        Path to the ELF file, or None if no known layout matches
+    """
+    name = build_path.name
+    for candidate in (
+        # Native ESP-IDF: the build writes build/<name>.elf, which ESPHome copies
+        # to build/firmware.elf (see espidf.toolchain.create_elf_copy)
+        build_path / "build" / "firmware.elf",
+        # PlatformIO
+        build_path / "firmware.elf",
+        build_path / ".pioenvs" / name / "firmware.elf",
+        # LibreTiny uses raw_firmware.elf
+        build_path / "raw_firmware.elf",
+        build_path / ".pioenvs" / name / "raw_firmware.elf",
+        # Zephyr (nRF52); the SDK nests the artifacts one level deeper from 2.9.2
+        build_path / ".pioenvs" / name / "zephyr" / "zephyr" / "zephyr.elf",
+        build_path / ".pioenvs" / name / "zephyr" / "zephyr.elf",
+    ):
+        if candidate.is_file():
+            return candidate
+    return None
+
+
+def idedata_candidates(build_path: Path) -> list[Path]:
+    """Return the idedata locations searched for a build directory, in order.
+
+    Exposed so a caller reporting "not found" can name the paths it tried
+    without keeping its own copy of the list.
+
+    Args:
+        build_path: Path to an ESPHome build directory
+
+    Returns:
+        The candidate idedata JSON paths, most specific first
+    """
+    name = build_path.name
+    data_dir = build_path.parent.parent / "idedata"
+    # Native backends suffix the cache by toolchain (<name>.arduino.json)
+    suffixed = sorted(data_dir.glob(f"{name}.*.json")) if data_dir.is_dir() else []
+    return [
+        # In .pioenvs for test builds
+        build_path / ".pioenvs" / name / "idedata.json",
+        # Both toolchains cache it in the data dir, which holds this build dir:
+        # <data_dir>/idedata/<name>.json next to <data_dir>/build/<name>
+        build_path.parent.parent / "idedata" / f"{name}.json",
+        *suffixed,
+        # Regular builds, invoked from the config dir or from anywhere
+        Path.cwd() / ".esphome" / "idedata" / f"{name}.json",
+        Path.home() / ".esphome" / "idedata" / f"{name}.json",
+    ]
+
+
+def find_idedata_path(build_path: Path) -> Path | None:
+    """Locate the idedata JSON belonging to an ESPHome build directory.
+
+    Args:
+        build_path: Path to an ESPHome build directory
+
+    Returns:
+        Path to the idedata JSON, or None if it was not found
+    """
+    for candidate in idedata_candidates(build_path):
+        if candidate.is_file():
+            return candidate
+    return None
+
+
 def _find_in_platformio_packages(tool_name: str) -> str | None:
     """Search for a tool in PlatformIO package directories.
 

esphome/api_client.py

@@ -0,0 +1,196 @@
+from __future__ import annotations
+
+import asyncio
+from contextlib import suppress
+import logging
+import threading
+from typing import TYPE_CHECKING, Any
+import warnings
+
+# Suppress protobuf version warnings
+with warnings.catch_warnings():
+    warnings.filterwarnings(
+        "ignore", category=UserWarning, message=".*Protobuf gencode version.*"
+    )
+    from aioesphomeapi import APIClient, parse_log_message
+    from aioesphomeapi.log_runner import async_run
+
+from esphome.const import CONF_ENCRYPTION, CONF_KEY, CONF_PORT, __version__
+from esphome.core import CORE
+from esphome.stacktrace import LogLineProcessor
+from esphome.util import safe_print
+
+if TYPE_CHECKING:
+    from collections.abc import Callable
+
+    from aioesphomeapi.api_pb2 import SubscribeLogsResponse  # pylint: disable=no-name-in-module
+
+
+_LOGGER = logging.getLogger(__name__)
+
+
+async def async_run_logs(
+    config: dict[str, Any],
+    addresses: list[str],
+    subscribe_states: bool = True,
+    mqtt_resolver: Callable[[threading.Event], list[str]] | None = None,
+) -> None:
+    """Run the logs command in the event loop.
+
+    If ``mqtt_resolver`` is given, it is called in a worker thread (paho-mqtt
+    has no asyncio support on Windows) concurrently with the connection
+    attempts to ``addresses``, and any addresses it discovers are fed into
+    the running client. It owns its own failure handling (returning [] when
+    discovery fails) and must honor the ``threading.Event`` it is passed so
+    teardown is not delayed by the lookup's wait window; the initial broker
+    connect itself is only bounded by the socket timeout.
+    """
+    from datetime import datetime
+
+    conf = config["api"]
+    name = config["esphome"]["name"]
+    port: int = int(conf[CONF_PORT])
+    noise_psk: str | None = None
+    if (encryption := conf.get(CONF_ENCRYPTION)) and (key := encryption.get(CONF_KEY)):
+        noise_psk = key
+
+    _LOGGER.info(
+        "Starting log output from %s using esphome API", " or ".join(addresses)
+    )
+
+    cli = APIClient(
+        addresses[0],  # Primary address for compatibility
+        port,
+        "",  # Password auth removed in 2026.1.0
+        client_info=f"ESPHome Logs {__version__}",
+        noise_psk=noise_psk,
+        addresses=addresses,  # Pass all addresses for automatic retry
+        provide_time=False,
+    )
+
+    # Decoder resolution policy lives in LogLineProcessor.
+    processor = LogLineProcessor(config, CORE.target_platform)
+
+    mqtt_task: asyncio.Task[None] | None = None
+    mqtt_stop_event = threading.Event()
+
+    def _cancel_mqtt_discovery() -> None:
+        """Stop the broker lookup once a connection has been established.
+
+        Its answer is only useful while still disconnected: after that it
+        either duplicates the connected address or arrives too late to
+        matter, so don't keep an idle broker session open for it.
+        """
+        mqtt_stop_event.set()
+        if mqtt_task is not None and not mqtt_task.done():
+            mqtt_task.cancel()
+
+    async def _resolve_mqtt_addresses() -> None:
+        """Discover the device address via the MQTT broker in the background."""
+        try:
+            mqtt_ips = await asyncio.to_thread(mqtt_resolver, mqtt_stop_event)
+            if not mqtt_ips:
+                _LOGGER.debug(
+                    "MQTT discovery %s",
+                    "aborted" if mqtt_stop_event.is_set() else "found no addresses",
+                )
+                return
+            if cli.add_addresses(mqtt_ips):
+                _LOGGER.info("Discovered address(es) via MQTT: %s", ", ".join(mqtt_ips))
+            else:
+                _LOGGER.debug(
+                    "MQTT-discovered address(es) already known: %s", ", ".join(mqtt_ips)
+                )
+        except Exception:  # pylint: disable=broad-except
+            # A background task failure would otherwise stay invisible for
+            # the whole session and only re-raise at teardown
+            _LOGGER.exception("MQTT address discovery failed")
+
+    def on_log(msg: SubscribeLogsResponse) -> None:
+        """Handle a new log message."""
+        time_ = datetime.now().astimezone()
+        message: bytes = msg.message
+        text = message.decode("utf8", "backslashreplace")
+        nanoseconds = time_.microsecond // 1000
+        timestamp = (
+            f"[{time_.hour:02}:{time_.minute:02}:{time_.second:02}.{nanoseconds:03}]"
+        )
+        for parsed_msg in parse_log_message(text, timestamp):
+            # safe_print handles the dashboard \033 escaping and falls back
+            # to backslashreplace encoding on stdouts that can't represent
+            # the wifi signal-bar block characters (Windows redirected
+            # cp1252 pipe).
+            safe_print(parsed_msg)
+        for raw_line in text.splitlines():
+            processor.process_line(raw_line)
+
+    # Safe to fall back to plaintext here only for this diagnostics use
+    # case: the stream is one-way from device to client, and this code
+    # never accepts commands or acts on any message the device sends.
+    # An on-path attacker could still both inject fabricated log lines
+    # and passively read the device's log output (and any state data
+    # delivered when subscribe_states is enabled), so this does lose
+    # confidentiality as well as authentication/integrity. That tradeoff
+    # is acceptable for operator-visible logs, which aioesphomeapi also
+    # warns may come from an unverified device. Never mirror this opt-in
+    # for any connection that sends data to the device or uses Home
+    # Assistant actions.
+    stop = await async_run(
+        cli,
+        on_log,
+        name=name,
+        subscribe_states=subscribe_states,
+        allow_plaintext_fallback=True,
+        # A top-level ``deep_sleep:`` block means the device is only awake
+        # briefly; cap the reconnect backoff so a wake window is not missed.
+        deep_sleep="deep_sleep" in config,
+        on_connect=_cancel_mqtt_discovery if mqtt_resolver is not None else None,
+    )
+    try:
+        # Don't start (or keep) the broker lookup if a connection already
+        # succeeded; the stop event doubles as the not-needed-anymore latch
+        # and get_esphome_device_ip returns immediately when it is set.
+        if mqtt_resolver is not None and not mqtt_stop_event.is_set():
+            mqtt_task = asyncio.create_task(_resolve_mqtt_addresses())
+        await asyncio.Event().wait()
+    finally:
+        try:
+            if mqtt_task is not None:
+                # Unblock the worker thread first so it can't hold up
+                # loop.shutdown_default_executor() for the full lookup timeout.
+                mqtt_stop_event.set()
+                # Give the worker a moment to exit through its own error
+                # handling; cancelling first would race out a late failure.
+                done, _ = await asyncio.wait([mqtt_task], timeout=1.0)
+                if not done:
+                    mqtt_task.cancel()
+                # return_exceptions keeps a CancelledError from the cancel()
+                # above from re-raising here and jumping over the stop() below.
+                # The task handles Exception itself, so only a BaseException
+                # escape (e.g. SystemExit from the worker) can land here.
+                (result,) = await asyncio.gather(mqtt_task, return_exceptions=True)
+                if isinstance(result, BaseException) and not isinstance(
+                    result, asyncio.CancelledError
+                ):
+                    _LOGGER.error("MQTT address discovery failed", exc_info=result)
+        finally:
+            # Must run even if a second cancellation lands mid-cleanup above
+            await stop()
+
+
+def run_logs(
+    config: dict[str, Any],
+    addresses: list[str],
+    subscribe_states: bool = True,
+    mqtt_resolver: Callable[[threading.Event], list[str]] | None = None,
+) -> None:
+    """Run the logs command."""
+    with suppress(KeyboardInterrupt):
+        asyncio.run(
+            async_run_logs(
+                config,
+                addresses,
+                subscribe_states=subscribe_states,
+                mqtt_resolver=mqtt_resolver,
+            )
+        )

esphome/arduino/library.py

@@ -0,0 +1,549 @@
+"""Arduino-core backend for the shared PlatformIO library converter.
+
+Bundled names build straight from the framework tree; everything else goes
+through ``esphome.platformio.library``. Mirrors ``lib_ldf_mode=off``: each
+library builds its own archive; all include dirs join one global path. The
+host build reuses it without a framework tree: nothing is bundled there and
+every name resolves from the registry.
+
+Deviations from PlatformIO: flat-layout libraries get the recursive default
+source filter; ``dot_a_linkage`` is honored; bundled libraries never run a
+manifest ``extraScript``; manifest ``-I`` flags join the global include path;
+``precompiled``/``ldflags`` properties are refused by name.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+import logging
+from pathlib import Path
+import re
+
+from esphome.core import CORE, EsphomeError, Library
+from esphome.helpers import walk_files
+from esphome.platformio.extra_script import apply_extra_script
+from esphome.platformio.library import (
+    DEFAULT_BUILD_INCLUDE_DIR,
+    DEFAULT_BUILD_SRC_FILTER,
+    ESPHOME_DATA_KEY,
+    ESPHOME_DATA_LINK_FLAGS_KEY,
+    LIBRARY_HEADER_SUFFIXES,
+    SRC_FILE_EXTENSIONS,
+    ConvertedLibrary,
+    IncompatiblePlatform,
+    InvalidLibrary,
+    LibraryBackend,
+    _url_or_none,
+    check_library_data,
+    collect_filtered_files,
+    convert_libraries,
+    ensure_list,
+    is_lib_ignored,
+    lex_build_flags,
+    lib_ignore_set,
+    normalize_dependencies,
+    parse_library_json,
+    parse_library_properties,
+    warn_properties_depends,
+)
+
+_LOGGER = logging.getLogger(__name__)
+
+
+@dataclass
+class ArduinoLibrary:
+    """One resolved library, ready for the ninja generator."""
+
+    name: str
+    sources: list[Path] = field(default_factory=list)
+    include_dirs: list[Path] = field(default_factory=list)
+    # Extra compile flags private to this library's own sources
+    flags: list[str] = field(default_factory=list)
+    # PlatformIO's build.libArchive / Arduino's dot_a_linkage: when False the
+    # objects go to the linker directly (symbols nothing references survive)
+    lib_archive: bool = True
+    # Link inputs the library contributes (-L dirs / -l libs, e.g. from
+    # precompiled vendor blobs) and -Wl, options for the firmware link
+    link_dirs: list[Path] = field(default_factory=list)
+    link_libs: list[str] = field(default_factory=list)
+    link_flags: list[str] = field(default_factory=list)
+
+
+# Source-like suffixes the case-sensitive suffix map rejects
+_UNMAPPED_SOURCE_SUFFIXES = frozenset(
+    {s.lower() for s in SRC_FILE_EXTENSIONS} | {".ino"}
+)
+
+# Filename-plain names: an allowlist excludes separators, drive colons,
+# and dot-only names by shape
+_SAFE_LIBRARY_NAME_RE = re.compile(r"[A-Za-z0-9_][A-Za-z0-9_. +-]*\Z")
+
+
+def _is_safe_library_name(name: object) -> bool:
+    """Whether a name may be joined under the framework's libraries dir."""
+    return isinstance(name, str) and _SAFE_LIBRARY_NAME_RE.fullmatch(name) is not None
+
+
+def _manifest_build(name: str, data: object) -> dict:
+    """The manifest's ``build`` section; malformed manifests fail by name."""
+    build = data.get("build", {}) if isinstance(data, dict) else None
+    if not isinstance(build, dict):
+        raise EsphomeError(f"Library {name} has a malformed manifest")
+    return build
+
+
+def _resolve_src_dir(name: str, read_path: Path, build: dict) -> str:
+    """Resolve PIO's source dir: manifest srcDir, else src/Src, else the root."""
+    if "srcDir" not in build:
+        return next((d for d in ("src", "Src") if (read_path / d).is_dir()), ".")
+    # A declared srcDir (falsy included) that does not resolve is a manifest error
+    src_dir = build["srcDir"]
+    if not (isinstance(src_dir, str) and src_dir and (read_path / src_dir).is_dir()):
+        raise EsphomeError(
+            f"Library {name} declares srcDir {src_dir!r} which does not exist"
+        )
+    return src_dir
+
+
+def _reject_unsupported_link_fields(name: str, data: dict) -> None:
+    # PIO honors these; ignoring them would fail at link with no stated
+    # cause. Property values are strings, so "false" is not a declaration.
+    precompiled = data.get("precompiled")
+    if precompiled and str(precompiled).strip().lower() != "false":
+        raise EsphomeError(
+            f"Library {name} declares precompiled, which this backend does not support"
+        )
+    if data.get("ldflags"):
+        raise EsphomeError(
+            f"Library {name} declares ldflags, which this backend does not support"
+        )
+
+
+def _resolve_lib_archive(name: str, data: dict, build: dict) -> bool:
+    """build.libArchive, else dot_a_linkage (an Arduino IDE property PIO
+    ignores; a deliberate extra), else archive."""
+
+    # Strict parse: bool("false") is True
+    def _parse(key: str, raw: object) -> bool:
+        if isinstance(raw, bool):
+            return raw
+        value = str(raw).strip().lower()
+        if value in ("true", "false"):
+            return value == "true"
+        raise EsphomeError(f"Library {name} has a malformed {key} value {raw!r}")
+
+    if "libArchive" in build:
+        return _parse("libArchive", build["libArchive"])
+    if "dot_a_linkage" in data:
+        return _parse("dot_a_linkage", data["dot_a_linkage"])
+    return True
+
+
+def _classify_build_flags(
+    name: str, read_path: Path, lib: ArduinoLibrary, flag_tokens: list[str]
+) -> list[str]:
+    """Route the lexed build.flags into the library's flag lists.
+
+    Returns the ``-I`` arguments for the include-dir resolution.
+    """
+    include_flags: list[str] = []
+    for tok in flag_tokens:
+        if tok.startswith("-I"):
+            include_flags.append(tok[2:])
+        elif tok.startswith("-L"):
+            link_dir = (read_path / tok[2:]).resolve()
+            if not link_dir.is_dir():
+                # Kept (the linker ignores missing -L dirs); the warning
+                # names the culprit before a bare "cannot find -lfoo"
+                _LOGGER.warning(
+                    "Library %s declares library dir %s which does not exist",
+                    name,
+                    tok[2:],
+                )
+            lib.link_dirs.append(link_dir)
+        elif tok.startswith("-l"):
+            lib.link_libs.append(tok[2:])
+        elif tok.startswith("-Wl,"):
+            lib.link_flags.append(tok)
+        else:
+            lib.flags.append(tok)
+    return include_flags
+
+
+def _resolve_include_dirs(
+    name: str,
+    read_path: Path,
+    lib: ArduinoLibrary,
+    build: dict,
+    src_dir: str,
+    include_flags: list[str],
+) -> None:
+    include_dir = build.get("includeDir", DEFAULT_BUILD_INCLUDE_DIR)
+    if not isinstance(include_dir, str):
+        raise EsphomeError(f"Library {name} has a malformed includeDir")
+    for d, explicit in [
+        (include_dir, "includeDir" in build),
+        (src_dir, False),  # _resolve_src_dir already validated it
+        *((flag, True) for flag in include_flags),
+    ]:
+        if (path := (read_path / d)).is_dir():
+            lib.include_dirs.append(path.resolve())
+        elif explicit:
+            # Warn-and-drop (unlike srcDir): a missing include dir is
+            # harmless until a header is needed, and the compile names it
+            _LOGGER.warning(
+                "Library %s declares include dir %s which does not exist", name, d
+            )
+
+
+def _collect_lib_sources(
+    name: str,
+    read_path: Path,
+    lib: ArduinoLibrary,
+    src_dir: str,
+    src_filter: list[str],
+) -> None:
+    sources: list[Path] = []
+    dropped: list[str] = []
+    saw_header = False
+    for f in collect_filtered_files(read_path / src_dir, src_filter):
+        path = Path(f)
+        suffix = path.suffix
+        if suffix in SRC_FILE_EXTENSIONS:
+            # resolve() per file: srcFilter patterns may escape src_dir
+            sources.append(path.resolve())
+        elif suffix.lower() in _UNMAPPED_SOURCE_SUFFIXES:
+            # A source-like suffix the case-sensitive map rejects (.CPP,
+            # .ino) is a dropped compilation unit; headers fall through
+            dropped.append(path.name)
+        elif suffix.lower() in LIBRARY_HEADER_SUFFIXES:
+            saw_header = True
+    lib.sources = sorted(sources)
+    if dropped:
+        _LOGGER.warning(
+            "Library %s: %d file(s) with unmapped source suffixes are not compiled: %s",
+            name,
+            len(dropped),
+            ", ".join(sorted(dropped)),
+        )
+    if not lib.sources and not saw_header:
+        # Matched headers mean header-only; a filter matching nothing is
+        # a manifest/tree problem (a truly empty tree raises elsewhere)
+        _LOGGER.warning("Library %s: no source files matched", name)
+
+
+def _library_info(name: str, read_path: Path, data: dict) -> ArduinoLibrary:
+    """Resolve one library's sources, include dirs, and flags (PIO semantics)."""
+    build = _manifest_build(name, data)
+    _reject_unsupported_link_fields(name, data)
+    src_dir = _resolve_src_dir(name, read_path, build)
+    src_filter = ensure_list(build.get("srcFilter", DEFAULT_BUILD_SRC_FILTER))
+    if not all(isinstance(entry, str) for entry in src_filter):
+        raise EsphomeError(f"Library {name} has a malformed srcFilter")
+    lib = ArduinoLibrary(name=name, lib_archive=_resolve_lib_archive(name, data, build))
+    # PlatformIO shell-lexes each build.flags entry
+    include_flags = _classify_build_flags(
+        name, read_path, lib, lex_build_flags(build.get("flags", []), f"library {name}")
+    )
+    _resolve_include_dirs(name, read_path, lib, build, src_dir, include_flags)
+    _collect_lib_sources(name, read_path, lib, src_dir, src_filter)
+    return lib
+
+
+def _bundled_library(framework_path: Path, name: str) -> ArduinoLibrary:
+    """A library bundled with the Arduino core, read from the framework tree.
+
+    ``library.json`` wins over ``library.properties`` when both exist, as in
+    PlatformIO's LibBuilderFactory; only the JSON manifest can carry a
+    ``build`` section (srcDir, srcFilter, flags).
+    """
+    lib_dir = framework_path / "libraries" / name
+    manifest_json = lib_dir / "library.json"
+    if manifest_json.is_file():
+        try:
+            data = parse_library_json(manifest_json)
+        except ValueError as err:  # JSONDecodeError
+            raise EsphomeError(
+                f"Bundled library {name} has a corrupt library.json ({err}); "
+                "the framework install may be incomplete (run 'esphome clean-all')"
+            ) from err
+    elif (manifest := lib_dir / "library.properties").is_file():
+        data = parse_library_properties(manifest)
+    else:
+        # Debug, not warning: the legacy manifest-less layout is legal and
+        # the 3.1.2 core ships one such library (FSTools), so a warning
+        # would be unactionable noise on every build using it
+        _LOGGER.debug("Bundled library %s has no manifest; using defaults", name)
+        data = {}
+    if isinstance(data, dict):
+        # Bundled manifest deps are never walked; make the skip visible
+        if data.get("dependencies"):
+            _LOGGER.warning(
+                "Bundled library %s declares dependencies, which are not "
+                "resolved automatically; add them with add_library() if needed",
+                name,
+            )
+        warn_properties_depends(name, data)
+        build = data.get("build")
+        if isinstance(build, dict) and build.get("extraScript"):
+            # Scripts only run on the converted path; building without
+            # the script's flags would miscompile
+            raise EsphomeError(
+                f"Bundled library {name} declares an extraScript, which is "
+                "not run for bundled libraries"
+            )
+    lib = _library_info(name, lib_dir, data)
+    _assert_tree_has_code(
+        name,
+        lib_dir,
+        "the framework install may be incomplete (run 'esphome clean-all')",
+    )
+    return lib
+
+
+def _assert_tree_has_code(name: str, root: Path, hint: str) -> None:
+    """An empty or half-extracted tree can never link; fail by name (a
+    warning would scroll away and resurface as undefined symbols)."""
+    if not any(
+        Path(p).suffix in SRC_FILE_EXTENSIONS
+        or Path(p).suffix.lower() in LIBRARY_HEADER_SUFFIXES
+        for p in walk_files(root)
+    ):
+        raise EsphomeError(f"Library {name} has no sources or headers; {hint}")
+
+
+def _external_short_name(name: str) -> str:
+    """The short library name of a requested spec.
+
+    "owner/Name" and plain names take the last path segment; "Name=<url>"
+    takes the declared name. Git tails (".git", "#ref") are stripped like
+    the walk's URL normalization; the comparand is a manifest dependency
+    name, never a spec.
+    """
+    head, sep, tail = name.partition("=")
+    if sep and "://" in tail:
+        return head
+    short = name.rsplit("/", maxsplit=1)[-1]
+    return short.partition("#")[0].removesuffix(".git")
+
+
+def _check_unfulfilled_provides(
+    provided_requests: set[str], satisfied: set[str], still_requested: set[str]
+) -> None:
+    """Fail by name when a walk-skipped dependency was never added.
+
+    An unfulfilled provides() promise only surfaces as undefined symbols
+    at link. The walk records across re-resolutions, so a name no final
+    manifest still requests is stale state, never a failure.
+    """
+    if missing := sorted((provided_requests & still_requested) - satisfied):
+        raise EsphomeError(
+            "provides() skipped these dependencies but nothing added them: "
+            f"{', '.join(missing)}; the build is missing libraries"
+        )
+
+
+def resolve_libraries(
+    framework_path: Path | None,
+    *,
+    pio_platform: str,
+    board_mcu: str,
+    cache_key: str,
+    framework: str | None = "arduino",
+    manifest_optional: bool = False,
+) -> list[ArduinoLibrary]:
+    """Resolve every ``cg.add_library()`` entry into an :class:`ArduinoLibrary`.
+
+    ``pio_platform``/``board_mcu`` filter manifests the way PlatformIO would
+    for that core (e.g. ``espressif8266``/``esp8266``); ``cache_key`` keys the
+    shared converter's download cache. ``framework`` is the manifest
+    framework token the compatibility check warns about; None skips it.
+    A None ``framework_path`` means no core-bundled libraries exist (the
+    host build): every name resolves from the registry.
+    ``manifest_optional`` accepts libraries without a manifest, built with
+    PlatformIO's default layout.
+
+    The returned list is not topologically sorted, so the caller must link
+    the archives inside one ``--start-group``/``--end-group`` pair (the
+    bundled-first grouping is incidental).
+    """
+    bundled: list[ArduinoLibrary] = []
+    external: list[Library] = []
+    # PlatformIO's lib_ignore covers framework-bundled libraries too; the
+    # shared converter only filters the registry/git ones.
+    lib_ignore = lib_ignore_set()
+    bundled_dir_names: frozenset[str] = frozenset()
+    if framework_path is not None:
+        # Exact directory names keep membership case-sensitive everywhere
+        # (an is_dir() probe would match "wire" on macOS/Windows and build
+        # the bundled Wire twice)
+        libraries_dir = framework_path / "libraries"
+        if not libraries_dir.is_dir():
+            # A registry fallback would fail later with a misleading
+            # package-not-found error per bundled name
+            raise EsphomeError(
+                f"{libraries_dir} is missing; the framework install may be "
+                "incomplete (run 'esphome clean-all')"
+            )
+        bundled_dir_names = frozenset(
+            p.name for p in libraries_dir.iterdir() if p.is_dir()
+        )
+
+    def _provided(name: object) -> bool:
+        return _is_safe_library_name(name) and name in bundled_dir_names
+
+    for library in CORE.platformio_libraries.values():
+        if is_lib_ignored(library.name, lib_ignore):
+            continue
+        # Bundled only for a bare name with a matching framework dir; pinned
+        # or unmatched names resolve from the registry, as under PlatformIO.
+        if not library.repository and not library.version and _provided(library.name):
+            # Bundled manifest deps are not walked; _bundled_library warns
+            bundled.append(_bundled_library(framework_path, library.name))
+        else:
+            external.append(library)
+
+    converted: list[ArduinoLibrary] = []
+    bundled_names = {lib.name for lib in bundled}
+    converted_manifest_names: set[str] = set()
+    # Bundled candidates skipped on purpose (platform filter); the
+    # provides() reconciliation must count them as satisfied
+    knowingly_skipped: set[str] = set()
+    # Dependency names of the manifests actually emitted; a walk recording
+    # for a since-re-resolved manifest must not fail the reconciliation
+    final_dep_names: set[str] = set()
+    # Ordered set of bundled dependency names to add once conversion is done
+    pending_bundled: dict[str, None] = {}
+    # Deps matching a separately-requested external are already in the build
+    # (a duplicate archive means duplicate-symbol link errors)
+    external_short_names = {
+        _external_short_name(lib.name) for lib in external if lib.name
+    }
+
+    def _add_bundled_dependencies(component: ConvertedLibrary) -> None:
+        # A version-less bare name ("Hash") is a core-bundled library the
+        # shared converter cannot resolve from the registry
+        for dep in normalize_dependencies(
+            component.data.get("dependencies"), component.name
+        ):
+            # normalize_dependencies guarantees a non-empty str name
+            name = dep["name"]
+            final_dep_names.add(name)
+            if "/" in name:
+                owner, _, pkg = name.partition("/")
+                if _is_safe_library_name(owner) and _is_safe_library_name(pkg):
+                    # Owner-qualified; the converter resolves it from the registry
+                    continue
+            if not _is_safe_library_name(name):
+                # The name becomes a path component; never join a traversal
+                _LOGGER.warning(
+                    "Ignoring malformed dependency entry %r of library %s",
+                    dep,
+                    component.name,
+                )
+                continue
+            if name in external_short_names:
+                if _provided(name):
+                    # A bundled copy is suppressed; a coincidental name
+                    # collision would surface as link errors
+                    _LOGGER.warning(
+                        "Dependency %s of %s is assumed satisfied by a "
+                        "requested external library; the bundled copy is "
+                        "not added",
+                        name,
+                        component.name,
+                    )
+                else:
+                    _LOGGER.debug(
+                        "Dependency %s of %s assumed satisfied by a requested "
+                        "external library",
+                        name,
+                        component.name,
+                    )
+                continue
+            if name in bundled_names or is_lib_ignored(name, lib_ignore):
+                continue
+            if _url_or_none(dep.get("version")) is not None:
+                # A URL names one specific source; never add the bundled copy
+                continue
+            if dep.get("owner") or not _provided(name):
+                # Only owner-less framework-tree names take the bundled
+                # copy (PIO's process_dependencies); the walk reports drops
+                continue
+            try:
+                # framework=None: the walk already warned for non-platform
+                # causes; debug keeps one fault from warning twice (pinned
+                # by test_nonplatform_rejection_warns_once_through_real_converter)
+                check_library_data(dep, pio_platform, None)
+            except IncompatiblePlatform as err:
+                # A knowing skip (platform filter), not a broken promise
+                knowingly_skipped.add(name)
+                _LOGGER.debug("Skip bundled candidate %s: %s", name, err)
+                continue
+            except InvalidLibrary as err:
+                # Malformed manifest data never counts as satisfied; the
+                # walk owns the warning (see the warns-once test above)
+                _LOGGER.debug("Skip malformed bundled candidate %s: %s", name, err)
+                continue
+            # Deferred: a later manifest name may satisfy this
+            pending_bundled.setdefault(name)
+
+    def _emit(component: ConvertedLibrary) -> None:
+        apply_extra_script(
+            component, board_mcu=lambda: board_mcu, pio_platform=pio_platform
+        )
+        _assert_tree_has_code(
+            component.get_require_name(),
+            component.source_dir,
+            "the download may be incomplete (run 'esphome clean-all')",
+        )
+        if isinstance(manifest_name := component.data.get("name"), str):
+            converted_manifest_names.add(manifest_name)
+        lib = _library_info(
+            component.get_require_name(), component.source_dir, component.data
+        )
+        # Extra-script LINKFLAGS travel outside build.flags; dropping
+        # them would link wrong with no stated cause
+        lib.link_flags.extend(
+            component.data.get(ESPHOME_DATA_KEY, {}).get(
+                ESPHOME_DATA_LINK_FLAGS_KEY, []
+            )
+        )
+        converted.append(lib)
+        _add_bundled_dependencies(component)
+
+    backend = LibraryBackend(
+        platform=pio_platform,
+        framework=framework,
+        emit=_emit,
+        cache_key=cache_key,
+        # The walk must not resolve bundled names from the registry;
+        # _add_bundled_dependencies adds them after emit
+        provides=_provided,
+        manifest_optional=manifest_optional,
+    )
+    if external:
+        convert_libraries(external, backend)
+    for name in pending_bundled:
+        if name in converted_manifest_names:
+            # The converted library is this one; the bundled copy would
+            # double the archive. Warn like the external_short_names twin.
+            _LOGGER.warning(
+                "Dependency %s is assumed satisfied by a converted library's "
+                "manifest name; the bundled copy is not added",
+                name,
+            )
+            continue
+        bundled_names.add(name)
+        bundled.append(_bundled_library(framework_path, name))
+
+    _check_unfulfilled_provides(
+        backend.provided_requests,
+        bundled_names
+        | converted_manifest_names
+        | external_short_names
+        | knowingly_skipped,
+        final_dep_names,
+    )
+
+    return bundled + converted

esphome/arduino8266/__init__.py

@@ -0,0 +1,9 @@
+"""Native (PlatformIO-free) build support for the ESP8266 Arduino core.
+
+This package downloads the Arduino ESP8266 core and the xtensa-lx106
+toolchain, generates a ninja build for them plus the ESPHome sources, and
+drives the build directly — the ESP8266 equivalent of ``esphome.espidf``.
+
+Deliberately importable without the esp8266 component to avoid circular
+imports; the component wires these modules in via lazy imports.
+"""

esphome/arduino8266/framework.py

@@ -0,0 +1,207 @@
+"""Download and install the Arduino ESP8266 core, toolchain, and ninja.
+
+Artifacts land in a machine-global cache (shared across projects, like the
+ESP-IDF install in ``esphome.espidf.framework``):
+
+    <cache>/arduino8266/frameworks/<tag>/   the Arduino core
+    <cache>/arduino8266/toolchains/<tag>/   xtensa-lx106-elf gcc 10.3
+
+Both come from esphome-libs releases pinned below;
+``ESPHOME_ARDUINO8266_*_MIRRORS`` overrides the URLs, with ``{VERSION}``
+standing for the release tag. ninja comes from PATH or the ninja PyPI wheel.
+"""
+
+from __future__ import annotations
+
+import os
+from pathlib import Path
+from typing import NamedTuple
+
+from esphome.build_helpers.ccache import ccache_env
+from esphome.build_helpers.ninja import find_ninja
+from esphome.build_helpers.tools_cache import ARDUINO8266_TOOLS_CACHE, tools_cache_path
+from esphome.core import EsphomeError, Version
+from esphome.framework_helpers import str_to_lst_of_str
+from esphome.platformio.registry import (
+    Download,
+    PackageSpec,
+    Resolver,
+    get_systype,
+    install_packages,
+    prefetch_packages,
+)
+
+FRAMEWORK_PACKAGE = "arduino-esp8266"
+_FRAMEWORK_RELEASES = "https://github.com/esphome-libs/arduino-esp8266/releases/"
+
+
+class FrameworkRelease(NamedTuple):
+    tag: str
+    sha256: str
+    size: int
+
+    def download(self) -> Download:
+        archive = f"{FRAMEWORK_PACKAGE}-{self.tag}.tar.gz"
+        url = f"{_FRAMEWORK_RELEASES}download/{self.tag}/{archive}"
+        return Download(url, self.sha256, self.size)
+
+
+# Arduino core version -> its build in esphome-libs/arduino-esp8266
+FRAMEWORK_RELEASES: dict[Version, FrameworkRelease] = {
+    Version(3, 1, 2): FrameworkRelease(
+        "3.1.2-esphome.3",
+        "3af533a85163804e164500a5b254dc23b922080e25ecb7dc37b3dd8ac84651db",
+        37185650,
+    ),
+}
+
+TOOLCHAIN_PACKAGE = "toolchain-xtensa-lx106-elf"
+# gcc 10.3, the toolchain Arduino core 3.x builds with; the build
+# generator's compile flags are tuned to it.
+TOOLCHAIN_VERSION = "10.3.0-esphome.3"
+_TOOLCHAIN_RELEASES = (
+    "https://github.com/esphome-libs/xtensa-lx106-elf-toolchain/releases/"
+)
+# Registry system tag -> (sha256, size) of that host's archive
+TOOLCHAIN_BUILDS: dict[str, tuple[str, int]] = {
+    "darwin_arm64": (
+        "ad0ea929238d9b527c43e0d20257acc2a5680bdb0d2b1cf8f2c99169786217e9",
+        60747260,
+    ),
+    "darwin_x86_64": (
+        "997090cac80c8eb59604ec52b73fb3568e5f2d9b2971f83c3f2a5c545c9c949c",
+        64065752,
+    ),
+    "linux_aarch64": (
+        "403f14d0d5755682fcd6eaea1e4c457a1d8cad30690e52fb0c804d8db266b908",
+        67487067,
+    ),
+    "linux_x86_64": (
+        "64f21fa3ba736b363dc8c234dbbb39e005e574e33de08a78e9a00c55a64ae706",
+        68343668,
+    ),
+    "windows_amd64": (
+        "1e62abf8df041ce5158f5770dffef955f2f981ce7f7adee88fcd5a8197705aa6",
+        67536405,
+    ),
+}
+
+ESPHOME_ARDUINO8266_FRAMEWORK_MIRRORS = str_to_lst_of_str(
+    os.environ.get("ESPHOME_ARDUINO8266_FRAMEWORK_MIRRORS", "")
+)
+ESPHOME_ARDUINO8266_TOOLCHAIN_MIRRORS = str_to_lst_of_str(
+    os.environ.get("ESPHOME_ARDUINO8266_TOOLCHAIN_MIRRORS", "")
+)
+
+
+def get_arduino8266_tools_path() -> Path:
+    # Machine-global so all projects share one install; see
+    # espidf.framework.get_idf_tools_path for the location rationale.
+    return tools_cache_path(*ARDUINO8266_TOOLS_CACHE)
+
+
+def framework_release(version: Version) -> FrameworkRelease:
+    if (release := FRAMEWORK_RELEASES.get(version)) is None:
+        raise EsphomeError(
+            f"'toolchain: arduino' has no build of Arduino core {version}; "
+            f"available: {', '.join(str(v) for v in FRAMEWORK_RELEASES)}. "
+            "Use one of those or 'toolchain: platformio'"
+        )
+    return release
+
+
+def get_framework_path(tag: str) -> Path:
+    return get_arduino8266_tools_path() / "frameworks" / tag
+
+
+def get_toolchain_path() -> Path:
+    return get_arduino8266_tools_path() / "toolchains" / TOOLCHAIN_VERSION
+
+
+def toolchain_download() -> Download:
+    """The toolchain archive for the current host."""
+    systype = get_systype()
+    if (build := TOOLCHAIN_BUILDS.get(systype)) is None:
+        raise EsphomeError(
+            f"There is no ESP8266 toolchain for this system ({systype}); "
+            f"supported systems are {', '.join(sorted(TOOLCHAIN_BUILDS))}. "
+            "Either set 'toolchain: platformio' under 'esp8266:', or point "
+            "ESPHOME_ARDUINO8266_TOOLCHAIN_MIRRORS at a toolchain archive"
+        )
+    sha256, size = build
+    archive = f"{TOOLCHAIN_PACKAGE}-{TOOLCHAIN_VERSION}-{systype}.tar.gz"
+    url = f"{_TOOLCHAIN_RELEASES}download/{TOOLCHAIN_VERSION}/{archive}"
+    return Download(url, sha256, size)
+
+
+class InstalledPaths(NamedTuple):
+    """Locations of the installed framework, toolchain, and ninja binary."""
+
+    framework: Path
+    toolchain: Path
+    ninja: Path
+
+
+def check_and_install(framework_version: Version) -> InstalledPaths:
+    """Ensure framework, toolchain, and ninja are installed; return their paths."""
+    release = framework_release(framework_version)
+    # Probe the cheap local dependency before ~110 MB of downloads
+    ninja_path = find_ninja()
+    framework_path = get_framework_path(release.tag)
+    downloads_dir = get_arduino8266_tools_path() / "downloads"
+    toolchain_path = get_toolchain_path()
+    # One spec per package: the prefetch and the installs must agree
+    specs = (
+        PackageSpec(
+            FRAMEWORK_PACKAGE,
+            release.tag,
+            framework_path,
+            ESPHOME_ARDUINO8266_FRAMEWORK_MIRRORS,
+            ("cores/esp8266", "tools/sdk", "libraries"),
+        ),
+        PackageSpec(
+            TOOLCHAIN_PACKAGE,
+            TOOLCHAIN_VERSION,
+            toolchain_path,
+            ESPHOME_ARDUINO8266_TOOLCHAIN_MIRRORS,
+            # xtensa-lx106-elf pins the target: every gcc package has a bin/
+            ("bin", "xtensa-lx106-elf"),
+        ),
+    )
+    # Resolved only when a download is needed, so an installed toolchain
+    # keeps working on a host without a build; a mirror override wins
+    resolvers: dict[str, Resolver] = {}
+    if not ESPHOME_ARDUINO8266_FRAMEWORK_MIRRORS:
+        resolvers[FRAMEWORK_PACKAGE] = release.download
+    if not ESPHOME_ARDUINO8266_TOOLCHAIN_MIRRORS:
+        resolvers[TOOLCHAIN_PACKAGE] = toolchain_download
+    # Fetch both archives at once; the installs verify and extract them.
+    # One spec list for both, so the two phases cannot drift.
+    prefetch_packages(specs, downloads_dir, resolvers)
+    install_packages(specs, downloads_dir, resolvers)
+    return InstalledPaths(
+        framework=framework_path, toolchain=toolchain_path, ninja=ninja_path
+    )
+
+
+def toolchain_tool(toolchain_path: Path, name: str) -> Path:
+    """Path to one toolchain tool (gcc, g++, ar, size, addr2line, ...).
+
+    The single owner of the ``bin/xtensa-lx106-elf-<name>`` layout and the
+    Windows suffix, so a toolchain package bump touches one spot.
+    """
+    suffix = ".exe" if os.name == "nt" else ""
+    return toolchain_path / "bin" / f"xtensa-lx106-elf-{name}{suffix}"
+
+
+def get_build_env(toolchain_path: Path, ccache: str | None) -> dict[str, str]:
+    env = os.environ.copy()
+    # Drop empty entries: a trailing separator from an absent PATH would
+    # make the shell search the current directory for tools
+    parts = [
+        str(toolchain_path / "bin"),
+        *filter(None, env.get("PATH", "").split(os.pathsep)),
+    ]
+    env["PATH"] = os.pathsep.join(parts)
+    env.update(ccache_env(ccache, ARDUINO8266_TOOLS_CACHE))
+    return env

esphome/arduino8266/toolchain.py

@@ -0,0 +1,212 @@
+"""Native Arduino ESP8266 build driver (the PlatformIO ``run`` equivalent)."""
+
+from __future__ import annotations
+
+import logging
+from pathlib import Path
+import subprocess
+from typing import TYPE_CHECKING
+
+from esphome.build_helpers.ccache import resolve_absolute_ccache_path
+from esphome.build_helpers.native import warn_ignored_platformio_options
+from esphome.build_helpers.ninja import refresh_compile_commands
+from esphome.const import (
+    CONF_COMPILE_PROCESS_LIMIT,
+    CONF_ESPHOME,
+    KEY_CORE,
+    KEY_FRAMEWORK_VERSION,
+)
+from esphome.core import CORE
+from esphome.types import ConfigType
+
+if TYPE_CHECKING:
+    from esphome.arduino8266.framework import InstalledPaths
+
+_LOGGER = logging.getLogger(__name__)
+
+# ESP8266 user RAM (matches upload.maximum_ram_size in every board manifest)
+_MAX_RAM_SIZE = 81920
+
+
+_RAM_SECTIONS = (".data", ".rodata", ".bss")
+_FLASH_SECTIONS = (".irom0.text", ".text", ".text1", ".data", ".rodata")
+
+
+def get_build_dir() -> Path:
+    return CORE.relative_pioenvs_path(CORE.name)
+
+
+def get_elf_path() -> Path:
+    return get_build_dir() / "firmware.elf"
+
+
+def _toolchain_tool(name: str) -> Path:
+    # Imported here, not at module scope: the serial upload/logs fast path
+    # resolves this module for its artifact paths alone, and framework
+    # pulls in the whole package-download stack
+    from esphome.arduino8266 import framework
+
+    return framework.toolchain_tool(framework.get_toolchain_path(), name)
+
+
+def get_factory_firmware_path() -> Path:
+    """The image to serial-flash at 0x0 (same bytes as firmware.bin: the
+    8266 factory copy exists for artifact-contract parity, not content)."""
+    return get_build_dir() / "firmware.factory.bin"
+
+
+def get_addr2line_path() -> Path:
+    return _toolchain_tool("addr2line")
+
+
+def get_objdump_path() -> Path:
+    return _toolchain_tool("objdump")
+
+
+def get_readelf_path() -> Path:
+    return _toolchain_tool("readelf")
+
+
+def run_compile(config: ConfigType, verbose: bool) -> int:
+    from esphome.arduino8266 import framework
+    from esphome.build_gen import arduino8266 as build_gen
+    from esphome.core.config import NATIVE_ARDUINO_CONSUMED_PIO_OPTIONS
+
+    warn_ignored_platformio_options(NATIVE_ARDUINO_CONSUMED_PIO_OPTIONS)
+    paths = framework.check_and_install(CORE.data[KEY_CORE][KEY_FRAMEWORK_VERSION])
+    # Resolved once: the probe is not free and three consumers need it
+    ccache = resolve_absolute_ccache_path()
+    ninja_changed = build_gen.write_project(paths, ccache)
+
+    build_dir = get_build_dir()
+    env = framework.get_build_env(paths.toolchain, ccache)
+    refresh_compile_commands(paths.ninja, build_dir, env, ninja_changed)
+
+    cmd = [str(paths.ninja)]
+    if verbose:
+        cmd.append("-v")
+    if jobs := config[CONF_ESPHOME].get(CONF_COMPILE_PROCESS_LIMIT):
+        cmd += ["-j", str(jobs)]
+    # Explicit targets: a generator defect that drops them fails loudly
+    # instead of a green no-op run leaving stale artifacts in place
+    targets = ["firmware.factory.bin", "firmware.ota.bin"]
+    cmd += targets
+
+    # cwd, not -C: drops ninja's "Entering directory" banner
+    _LOGGER.debug("Running: %s", " ".join(cmd))
+    rc = subprocess.run(
+        cmd, cwd=build_dir, env=env, check=False, close_fds=False
+    ).returncode
+    if rc != 0:
+        return rc
+
+    # ninja already refused missing targets; existence covers a rule that
+    # ran but wrote elsewhere
+    build_dir_artifacts = (
+        get_elf_path(),
+        build_dir / "firmware.bin",
+        get_factory_firmware_path(),
+        build_dir / "firmware.ota.bin",
+    )
+    for artifact in build_dir_artifacts:
+        if not artifact.is_file():
+            _LOGGER.error("Build produced no %s", artifact)
+            return 1
+
+    if not _print_size_summary(build_dir, paths):
+        # Cause already warned; name the consequence for CI harnesses
+        _LOGGER.warning("Firmware size summary unavailable for this build")
+    from esphome.build_helpers.idedata import warn_if_idedata_missing
+
+    warn_if_idedata_missing(lambda: get_idedata(ccache))
+    return 0
+
+
+def _parse_app_size(build_dir: Path, paths: InstalledPaths) -> int | None:
+    """Read the app flash budget (irom0_0_seg length) from the linker script."""
+    from esphome.build_gen.arduino8266 import get_flash_ld_path
+    from esphome.components.esp8266.build_surgery import segment_length
+
+    # Warnings, not debug: without the app size the Flash summary line is
+    # dropped and CI's memory-impact extraction loses its flash metric.
+    ld_path = get_flash_ld_path(build_dir, paths)
+    try:
+        ld_text = ld_path.read_text(encoding="utf-8")
+    except (OSError, UnicodeDecodeError) as err:
+        # A corrupt script degrades the same way, never aborts the build
+        _LOGGER.warning("Cannot read linker script for the Flash summary: %s", err)
+        return None
+    if not (app_size := segment_length(ld_text, "irom0_0_seg")):
+        _LOGGER.warning("No usable irom0_0_seg in %s; skipping Flash summary", ld_path)
+        return None
+    return app_size
+
+
+def _print_size_summary(build_dir: Path, paths: InstalledPaths) -> bool:
+    """Print the RAM/Flash lines ``ci_memory_impact_extract.py`` parses;
+    False when skipped."""
+    from esphome.arduino8266.framework import toolchain_tool
+    from esphome.build_helpers.size_summary import print_size_line
+
+    try:
+        result = subprocess.run(
+            [
+                str(toolchain_tool(paths.toolchain, "size")),
+                "-A",
+                "-d",
+                str(build_dir / "firmware.elf"),
+            ],
+            capture_output=True,
+            text=True,
+            check=True,
+            close_fds=False,
+        )
+    except (OSError, subprocess.CalledProcessError) as err:
+        # The summary is a bonus artifact like idedata; a truncated
+        # toolchain extraction must not discard an already-linked build
+        _LOGGER.warning("Could not summarize firmware size: %s", err)
+        return False
+    # -d prints decimal sizes; anything else trips the missing-sections guard
+    sections = {
+        parts[0]: int(parts[1])
+        for line in result.stdout.splitlines()
+        if (parts := line.split())[:1] and parts[0].startswith(".") and len(parts) >= 2
+        if parts[1].isdigit()
+    }
+    if missing := set(_RAM_SECTIONS + _FLASH_SECTIONS) - set(sections):
+        # A defaulted 0 would print a confidently wrong total for CI's metric
+        _LOGGER.warning(
+            "Size output is missing section(s) %s; skipping the size summary",
+            ", ".join(sorted(missing)),
+        )
+        return False
+    # Resolve the flash budget before printing: a RAM line without its
+    # Flash line would skew CI's memory-impact extraction
+    app_size = _parse_app_size(build_dir, paths)
+    if not app_size:
+        return False
+    ram = sum(sections[s] for s in _RAM_SECTIONS)
+    flash = sum(sections[s] for s in _FLASH_SECTIONS)
+    print_size_line("RAM", ram, _MAX_RAM_SIZE)
+    print_size_line("Flash", flash, app_size)
+    return True
+
+
+def get_idedata(ccache: str | None = None) -> dict | None:
+    """Derive idedata from the build's compile_commands.json (same
+    contract as ``espidf.toolchain.get_idedata``)."""
+    from esphome.build_helpers.idedata import load_or_build_idedata
+
+    # A disabled ccache resolves to None without spawning anything, so
+    # re-resolving here costs nothing when the caller has no answer
+    launcher = ccache or resolve_absolute_ccache_path()
+    return load_or_build_idedata(
+        get_build_dir() / "compile_commands.json",
+        get_elf_path(),
+        # Suffixed so a platformio->arduino->platformio round trip on one
+        # config never serves the other toolchain's cache shape
+        CORE.relative_internal_path("idedata", f"{CORE.name}.arduino.json"),
+        # The compile DB's commands carry the same ccache prefix the ninja
+        # rules were generated with
+        launcher=str(launcher) if launcher else None,
+    )

esphome/async_thread.py

@@ -11,43 +11,136 @@ from __future__ import annotations
 
 import asyncio
 from collections.abc import Awaitable, Callable
+from itertools import count
+import logging
 import threading
+from typing import cast
+
+_LOGGER = logging.getLogger(__name__)
+
+# How long the orphan watcher waits for an abandoned coroutine before giving
+# up, so a hung operation does not park a watcher thread forever.
+ORPHAN_WAIT_TIMEOUT = 300.0
+
+
+_runner_ids = count(1)
+
+
+class AsyncDispatchTimeout(TimeoutError):
+    """The caller stopped waiting; the coroutine was abandoned.
+
+    A subclass so callers can tell the dispatcher's own expiry apart from a
+    ``TimeoutError`` raised inside the coroutine, while existing
+    ``except TimeoutError`` handlers keep working.
+    """
 
 
 class AsyncThreadRunner[T](threading.Thread):
     """Run an async coroutine in a daemon thread and expose its result.
 
-    The runner catches all exceptions from the coroutine and stores them in
-    ``exception`` so ``event`` is always set — this prevents callers waiting
-    on ``event`` from hanging forever when the coroutine crashes.
-
-    Typical usage::
-
-        runner = AsyncThreadRunner(lambda: my_coro(arg))
-        runner.start()
-        if not runner.event.wait(timeout=5.0):
-            ...  # timed out
-        if runner.exception is not None:
-            raise runner.exception
-        result = runner.result
+    ``event`` is always set, even when the coroutine crashes, so waiters
+    never hang; ``completed`` distinguishes a delivered result (even a
+    legitimate ``None``) from a coroutine that never finished. Prefer
+    :func:`run_async`; use this class directly only when a failure should
+    degrade to a default value instead of raising.
     """
 
     def __init__(self, coro_factory: Callable[[], Awaitable[T]]) -> None:
-        super().__init__(daemon=True)
+        super().__init__(daemon=True, name=f"async-thread-runner-{next(_runner_ids)}")
         self._coro_factory = coro_factory
         self.result: T | None = None
         self.exception: BaseException | None = None
+        self.completed = False
         self.event = threading.Event()
 
     async def _runner(self) -> None:
         try:
             self.result = await self._coro_factory()
-        except Exception as exc:  # noqa: BLE001  # pylint: disable=broad-except
-            # Capture all exceptions so ``event`` is always set — otherwise a
-            # crash would hang the waiter forever.
+            # Distinguishes a delivered result from "never ran", since None
+            # is a valid result value.
+            self.completed = True
+        except BaseException as exc:  # noqa: BLE001  # pylint: disable=broad-except
+            # Capture everything, including BaseException — otherwise a
+            # cancellation or SystemExit would leave ``exception`` unset and
+            # waiters would mistake the empty ``result`` for success.
             self.exception = exc
         finally:
             self.event.set()
 
     def run(self) -> None:
-        asyncio.run(self._runner())
+        try:
+            asyncio.run(self._runner())
+        except BaseException as exc:  # noqa: BLE001  # pylint: disable=broad-except
+            # asyncio.run itself can fail before _runner executes (e.g. loop
+            # creation under fd exhaustion); record it so waiters never hang.
+            # A failure during loop cleanup after the coroutine completed
+            # must not clobber the delivered result, hence the guard.
+            if self.exception is None and not self.completed:
+                self.exception = exc
+            else:
+                _LOGGER.debug(
+                    "Event loop teardown failed after outcome recorded",
+                    exc_info=True,
+                )
+        finally:
+            self.event.set()
+
+
+def run_async[T](
+    coro_factory: Callable[[], Awaitable[T]],
+    timeout: float | None = None,
+    on_orphan: Callable[[T], None] | None = None,
+) -> T:
+    """Run a coroutine in a daemon-thread event loop and return its result.
+
+    Raises :class:`AsyncDispatchTimeout` if the coroutine does not finish
+    within ``timeout`` seconds; the thread is abandoned and exits with the
+    interpreter. If the abandoned coroutine later produces a result,
+    ``on_orphan`` (if given) is called with it so resources such as a
+    connected socket can be released; delivery is best effort and bounded
+    by ``ORPHAN_WAIT_TIMEOUT``.
+    """
+    runner: AsyncThreadRunner[T] = AsyncThreadRunner(coro_factory)
+    runner.start()
+    if not runner.event.wait(timeout):
+
+        def _cleanup() -> None:
+            if not runner.event.wait(ORPHAN_WAIT_TIMEOUT):
+                # The one state where a resource can genuinely leak; leave
+                # a trace so a recurring hang is attributable.
+                _LOGGER.info(
+                    "Orphan watcher gave up after %.0fs; a late result may leak",
+                    ORPHAN_WAIT_TIMEOUT,
+                )
+                return
+            if not runner.completed:
+                # The only place an abandoned thread's real error surfaces;
+                # without it a late failure hides behind the TimeoutError.
+                # INFO, not DEBUG: it fires at most once per abandoned
+                # operation and the cause may not reproduce on a rerun.
+                _LOGGER.info(
+                    "Abandoned async operation failed",
+                    exc_info=runner.exception,
+                )
+                return
+            if (result := runner.result) is None:
+                return
+            if on_orphan is None:
+                _LOGGER.debug("Discarding late result; no on_orphan handler")
+                return
+            try:
+                on_orphan(result)
+            except Exception:  # pylint: disable=broad-except
+                # INFO, not DEBUG: a failed release means a real leak, and
+                # it fires at most once per abandoned operation.
+                _LOGGER.info("Error releasing orphaned result", exc_info=True)
+
+        threading.Thread(
+            target=_cleanup, daemon=True, name="async-orphan-cleanup"
+        ).start()
+        raise AsyncDispatchTimeout("Timed out waiting for async operation")
+    if (exc := runner.exception) is not None:
+        raise exc
+    if not runner.completed:
+        raise RuntimeError("Async operation finished without a result or an exception")
+    return cast("T", runner.result)

esphome/automation.py

@@ -1,5 +1,8 @@
+from collections.abc import Awaitable, Callable, Sequence
 from dataclasses import dataclass, field
 import logging
+import string
+from typing import Any
 
 import esphome.codegen as cg
 import esphome.config_validation as cv
@@ -18,18 +21,46 @@ from esphome.const import (
     CONF_TYPE_ID,
     CONF_UPDATE_INTERVAL,
 )
-from esphome.core import ID, Lambda
+from esphome.core import CORE, ID, EsphomeError, HexInt, Lambda
 from esphome.cpp_generator import (
+    Expression,
     LambdaExpression,
     MockObj,
     MockObjClass,
     TemplateArgsType,
+    call_lambda,
 )
 from esphome.schema_extractors import SCHEMA_EXTRACT, schema_extractor
-from esphome.types import ConfigType
+from esphome.types import ConfigType, SafeExpType
 from esphome.util import Registry
 
 
+def progmem_bytes(name: str, data: bytes | list[int]) -> MockObj:
+    """Shared PROGMEM table for constant bytes; equal payloads share one, empty is nullptr."""
+    if not data:
+        return cg.nullptr
+    return cg.shared_progmem_array(
+        name, cg.uint8, cg.ArrayInitializer(*(HexInt(x) for x in data))
+    )
+
+
+async def templatable_bytes(
+    value: Any,
+    args: TemplateArgsType,
+    set_template: MockObj,
+    set_static: MockObj,
+    table_name: str,
+) -> None:
+    """Set a TemplatableBytes: a lambda via set_template, constant bytes via set_static."""
+    if cg.is_template(value):
+        fn = await cg.templatable(value, args, cg.std_vector.template(cg.uint8))
+        cg.add(set_template(fn))
+    elif len(value) > 0xFFFF:
+        raise EsphomeError(f"Byte payload is {len(value)} bytes; the maximum is 65535")
+    else:
+        cg.add(set_static(progmem_bytes(table_name, value), len(value)))
+
+
 def maybe_simple_id(*validators):
     """Allow a raw ID to be specified in place of a config block.
     If the value that's being validated is a dictionary, it's passed as-is to the specified validators. Otherwise, it's
@@ -57,6 +88,7 @@ def maybe_conf(conf, *validators):
         with cv.remove_prepend_path([conf]):
             return validator({conf: value})
 
+    validate.inner_schema = validator
     return validate
 
 
@@ -102,6 +134,101 @@ def register_condition(name: str, condition_type: MockObjClass, schema: cv.Schem
     return CONDITION_REGISTRY.register(name, condition_type, schema)
 
 
+async def _build_with_parent(
+    config: ConfigType,
+    automation_id: ID,
+    template_arg: cg.TemplateArguments,
+    args: TemplateArgsType,
+) -> MockObj:
+    parent = await cg.get_variable(config[CONF_ID])
+    return cg.new_Pvariable(automation_id, template_arg, parent)
+
+
+async def _build_without_parent(
+    config: ConfigType,
+    automation_id: ID,
+    template_arg: cg.TemplateArguments,
+    args: TemplateArgsType,
+) -> MockObj:
+    return cg.new_Pvariable(automation_id, template_arg)
+
+
+async def _build_parented(
+    config: ConfigType,
+    automation_id: ID,
+    template_arg: cg.TemplateArguments,
+    args: TemplateArgsType,
+) -> MockObj:
+    var = cg.new_Pvariable(automation_id, template_arg)
+    await cg.register_parented(var, config[CONF_ID])
+    return var
+
+
+def register_simple_action(
+    name: str,
+    action_type: MockObjClass,
+    schema: cv.Schema,
+    *,
+    synchronous: bool,
+) -> None:
+    """Register an action whose constructor takes the object named by ``config[CONF_ID]``.
+
+    Use the ``register_action`` decorator instead when the builder must also set fields.
+    """
+    register_action(name, action_type, schema, synchronous=synchronous)(
+        _build_with_parent
+    )
+
+
+def register_simple_condition(
+    name: str, condition_type: MockObjClass, schema: cv.Schema
+) -> None:
+    """Condition counterpart of ``register_simple_action``."""
+    register_condition(name, condition_type, schema)(_build_with_parent)
+
+
+def register_bare_action(
+    name: str,
+    action_type: MockObjClass,
+    schema: cv.Schema,
+    *,
+    synchronous: bool,
+) -> None:
+    """Register an action whose constructor takes no arguments."""
+    register_action(name, action_type, schema, synchronous=synchronous)(
+        _build_without_parent
+    )
+
+
+def register_bare_condition(
+    name: str, condition_type: MockObjClass, schema: cv.Schema
+) -> None:
+    """Condition counterpart of ``register_bare_action``."""
+    register_condition(name, condition_type, schema)(_build_without_parent)
+
+
+def register_parented_action(
+    name: str,
+    action_type: MockObjClass,
+    schema: cv.Schema,
+    *,
+    synchronous: bool,
+) -> None:
+    """Register an action deriving from ``Parented<T>``.
+
+    The object is constructed without arguments and ``set_parent()`` receives the object
+    named by ``config[CONF_ID]``.
+    """
+    register_action(name, action_type, schema, synchronous=synchronous)(_build_parented)
+
+
+def register_parented_condition(
+    name: str, condition_type: MockObjClass, schema: cv.Schema
+) -> None:
+    """Condition counterpart of ``register_parented_action``."""
+    register_condition(name, condition_type, schema)(_build_parented)
+
+
 Action = cg.esphome_ns.class_("Action")
 Trigger = cg.esphome_ns.class_("Trigger")
 ACTION_REGISTRY = Registry()
@@ -112,6 +239,376 @@ validate_action_list = cv.validate_registry("action", ACTION_REGISTRY)
 validate_condition = cv.validate_registry_entry("condition", CONDITION_REGISTRY)
 validate_condition_list = cv.validate_registry("condition", CONDITION_REGISTRY)
 
+ApplyAction = cg.esphome_ns.class_("ApplyAction", Action)
+ApplyCondition = cg.esphome_ns.class_("ApplyCondition", Condition)
+
+
+def flash_string(config: ConfigType, value: str) -> str:
+    """Default renderer for ``std::string`` constants; copies the literal out of flash on ESP8266."""
+    return str(cg.progmem_string(value))
+
+
+def flash_compare(config: ConfigType, value: str) -> str:
+    """Default renderer for ``std::string`` constants in conditions; compares in flash on ESP8266."""
+    if CORE.is_esp8266:
+        return f"::esphome::ProgmemStringRef{{PSTR({cg.safe_exp(value)}), {len(value.encode('utf-8'))}}}"
+    return str(cg.safe_exp(value))
+
+
+def _default_std_string(
+    members: list[tuple[str, Any, Any]], renderer: Callable[[ConfigType, str], str]
+) -> list[tuple[str, Any, Any]]:
+    """Give ``cg.std_string`` members without a renderer the given default."""
+    return [
+        (key, t, fn or (renderer if t is cg.std_string else None))
+        for key, t, fn in members
+    ]
+
+
+def literal_with_length(config: ConfigType, value: str) -> str:
+    """Renderer for a ``(const char *, size_t)`` target: a plain literal plus its byte length.
+
+    The target compares or copies the bytes in place, so it needs the RAM literal rather than
+    the PROGMEM rendering on ESP8266, and the length saves a strlen.
+    """
+    return f"{cg.safe_exp(value)}, {len(value.encode('utf-8'))}"
+
+
+def string_ref_literal(config: ConfigType, value: str) -> str:
+    """Renderer for a ``StringRef`` comparison: a flash literal on ESP8266, else ``StringRef(literal, length)``."""
+    if CORE.is_esp8266:
+        return str(cg.FlashStringLiteral(value))
+    return f"StringRef({literal_with_length(config, value)})"
+
+
+def _names_parent(text: str) -> bool:
+    return any(f == "parent" for _, f, _, _ in string.Formatter().parse(text))
+
+
+@dataclass(frozen=True)
+class ApplyCall:
+    """One statement from config keys, e.g. ``"set_range({}, {})"`` with ``((CONF_LOW, cg.float_), ...)``.
+
+    Each arg is ``(conf_key, type_)`` or ``(conf_key, type_, const_fn)``. A ``conf_key`` may be a
+    path into nested sections. ``target`` and a plain ``str`` ``type_`` (raw C++ type text) may
+    name the parent object as ``{parent}``. ``const_fn(config, value)`` renders a constant's argument text; a lambda or an
+    id bypasses it. The statement is skipped when none of its keys is set, always emitted when it
+    has no keys, and a partial set is a config error.
+    """
+
+    target: str
+    args: tuple[tuple[Any, ...], ...] = ()
+
+    def __post_init__(self) -> None:
+        fields = [
+            f for _, f, _, _ in string.Formatter().parse(self.target) if f is not None
+        ]
+        if any(f not in ("", "parent") for f in fields):
+            raise ValueError(
+                f"apply target {self.target!r}: only {{}} and {{parent}} placeholders"
+            )
+        if (count := fields.count("")) != len(self.args):
+            raise ValueError(
+                f"apply target {self.target!r} has {count} "
+                f"placeholder(s) for {len(self.args)} config key(s)"
+            )
+        if any(len(arg) not in (2, 3) for arg in self.args):
+            raise ValueError(
+                f"apply target {self.target!r}: each arg is (conf_key, type_[, const_fn])"
+            )
+
+    @property
+    def names_parent(self) -> bool:
+        return _names_parent(self.target) or any(
+            isinstance(arg[1], str) and _names_parent(arg[1]) for arg in self.args
+        )
+
+    @property
+    def members(self) -> list[tuple[Any, Any, Any]]:
+        """Each arg as ``(conf_key, type_, const_fn or None)``."""
+        return [
+            (arg[0], arg[1], arg[2] if len(arg) == 3 else None) for arg in self.args
+        ]
+
+
+@dataclass(frozen=True)
+class ApplyField:
+    """One config key forwarded as ``target(value)``, or as statement ``target`` when it has ``{}``.
+
+    Double a literal brace in a template. ``conf_key`` may be a path into nested sections.
+    ``type_`` may be a C++ type string using ``{parent}`` when the type is only known per
+    instance. ``const_fn(config, value)`` renders a constant's argument text when ``cg.safe_exp``
+    is not the right spelling (unit conversion belongs in the validator); a lambda or an id
+    bypasses it, so the target must also take a plain ``type_``. An absent key emits nothing.
+    """
+
+    conf_key: str | tuple[str, ...]
+    target: str
+    type_: SafeExpType
+    const_fn: Callable[[ConfigType, Any], str] | None = None
+
+    def call(self) -> ApplyCall:
+        target = self.target if "{}" in self.target else f"{self.target}({{}})"
+        return ApplyCall(target, ((self.conf_key, self.type_, self.const_fn),))
+
+
+def _config_lookup(config: ConfigType, key: str | tuple[str, ...]) -> Any:
+    if isinstance(key, str):
+        return config.get(key)
+    for part in key:
+        if (config := config.get(part)) is None:
+            return None
+    return config
+
+
+def _dict_schema(schema: Any) -> Any:
+    """The dict-backed cv.Schema inside cv.All and maybe_* wrappers, or None; cv.Any is not inspected."""
+    if isinstance(schema, dict):
+        return cv.Schema(schema)
+    if isinstance(getattr(schema, "schema", None), dict):
+        return schema
+    if isinstance(schema, cv.All):
+        inner = schema.validators
+    else:
+        inner = (
+            getattr(schema, "inner_schema", None),
+        )  # maybe_conf / maybe_simple_value
+    for candidate in inner:
+        if candidate is not None and (found := _dict_schema(candidate)) is not None:
+            return found
+    return None
+
+
+def _check_key_in_schema(
+    name: str, schema: Any, conf_key: str | tuple[str, ...]
+) -> None:
+    """Reject a key path the schema does not have; a typo would otherwise be a silent no-op.
+
+    Only dict-backed schemas, also inside cv.All and maybe_* wrappers, can be checked.
+    """
+    for part in (conf_key,) if isinstance(conf_key, str) else conf_key:
+        if (schema := _dict_schema(schema)) is None:
+            return
+        markers = {
+            getattr(marker, "schema", marker): marker for marker in schema.schema
+        }
+        if part not in markers:
+            raise ValueError(f"{name}: config key {part!r} is not in the schema")
+        schema = schema.schema[markers[part]]
+
+
+def parent_ref(var: MockObj) -> MockObj:
+    """``var`` named from global scope, so a trigger argument cannot shadow it.
+
+    Also how a generated callback names its Automation.
+    """
+    return MockObj(f"::{var}", "->")
+
+
+async def _apply_parent(config: ConfigType, id_key: str = CONF_ID) -> str:
+    return str(parent_ref(await cg.get_variable(config[id_key])))
+
+
+def _apply_lambda_args(args: TemplateArgsType) -> TemplateArgsType:
+    # The generated function's parameters; a std::string arg is never copied.
+    return [
+        (cg.RawExpression(f"const std::remove_cvref_t<{cg.safe_exp(t)}> &"), arg)
+        for t, arg in args
+    ]
+
+
+def _apply_function(
+    id_: ID,
+    return_type: SafeExpType,
+    template_arg: cg.TemplateArguments,
+    lambda_args: TemplateArgsType,
+    statements: list[str],
+) -> MockObj:
+    """Emit the generated function and declare ``id_`` as the ``ApplyAction`` or
+    ``ApplyCondition`` templated on it, so ``play()`` calls it directly."""
+    fn = cg.static_function(
+        f"esphome__{id_.id}__fn", return_type, lambda_args, statements
+    )
+    return cg.new_Pvariable(id_, cg.TemplateArguments(fn, *template_arg))
+
+
+async def _render_values(
+    name: str,
+    target: str,
+    members: list[tuple[Any, Any, Any]],
+    values: list[Any],
+    config: ConfigType,
+    parent: str | None,
+    lambda_args: TemplateArgsType,
+    compare: bool = False,
+) -> list[str]:
+    """Render the argument text of one statement; every key must be present.
+
+    ``compare``: an inlined lambda expression is parenthesized so it binds as a whole
+    beside an operator.
+    """
+    if any(value is None for value in values):
+        keys = [key for key, _, _ in members]
+        raise EsphomeError(f"{name}: {target!r} needs all of {keys}")
+    exprs: list[str] = []
+    for (_, type_, const_fn), value in zip(members, values, strict=True):
+        if isinstance(value, Lambda):
+            if isinstance(type_, str):
+                type_ = cg.RawExpression(type_.format(parent=parent))
+            inner = await cg.process_lambda(value, lambda_args, return_type=type_)
+            expr = call_lambda(inner)
+            bare = compare and isinstance(expr, cg.RawExpression)
+            exprs.append(f"({expr})" if bare else str(expr))
+        elif isinstance(value, ID):
+            # Qualified like the parent, so a trigger arg named like the id cannot shadow it.
+            exprs.append(f"::{await cg.get_variable(value)}")
+        elif const_fn is not None:
+            exprs.append(const_fn(config, value))
+        else:
+            exprs.append(str(cg.safe_exp(value)))
+    return exprs
+
+
+def _apply_values(config: ConfigType, members: list[tuple[Any, Any, Any]]) -> list[Any]:
+    return [_config_lookup(config, key) for key, _, _ in members]
+
+
+def register_apply_action(
+    name: str,
+    schema: cv.Schema,
+    *fields: ApplyField | ApplyCall,
+    call: str | None = None,
+    id_key: str = CONF_ID,
+) -> None:
+    """Register an action that only forwards config values to its parent, with no C++ class.
+
+    See ``apply_action_builder``.
+    """
+    register_action(name, ApplyAction, schema, synchronous=True)(
+        apply_action_builder(name, schema, *fields, call=call, id_key=id_key)
+    )
+
+
+def apply_action_builder(
+    name: str,
+    schema: cv.Schema,
+    *fields: ApplyField | ApplyCall,
+    call: str | None = None,
+    id_key: str = CONF_ID,
+) -> Callable[..., Awaitable[MockObj]]:
+    """The builder ``register_apply_action`` registers, for a caller that wraps it.
+
+    Generates one static function with the parent (read from ``id_key``) and constants baked
+    in, lambdas called inline with the trigger args, and an ``ApplyAction`` templated on it.
+    A constant that is an id (``cv.use_id`` under ``cv.templatable``) is the object it names.
+    With ``call`` every statement targets the call object ``auto apply_call = parent->call()``,
+    and ``apply_call.perform()`` is appended.
+    """
+    # An action stores the value, so a std::string constant stays in flash on ESP8266.
+    statements_spec = [
+        (
+            c.target,
+            _default_std_string(c.members, flash_string),
+        )
+        for c in (f if isinstance(f, ApplyCall) else f.call() for f in fields)
+    ]
+    _check_key_in_schema(name, schema, id_key)
+    for _, members in statements_spec:
+        for conf_key, _, _ in members:
+            _check_key_in_schema(name, schema, conf_key)
+
+    async def builder(
+        config: ConfigType,
+        action_id: ID,
+        template_arg: cg.TemplateArguments,
+        args: TemplateArgsType,
+    ) -> MockObj:
+        parent = await _apply_parent(config, id_key)
+        lambda_args = _apply_lambda_args(args)
+        receiver = "apply_call." if call else f"{parent}->"
+        statements: list[str] = []
+        for target, members in statements_spec:
+            values = _apply_values(config, members)
+            if not _apply_call_active(members, values):
+                continue
+            exprs = await _render_values(
+                name, target, members, values, config, parent, lambda_args
+            )
+            statements.append(f"{receiver}{target.format(*exprs, parent=parent)};")
+        if call:
+            statements = [
+                f"auto apply_call = {parent}->{call}();",
+                *statements,
+                "apply_call.perform();",
+            ]
+        return _apply_function(
+            action_id, cg.void, template_arg, lambda_args, statements
+        )
+
+    return builder
+
+
+def _apply_call_active(members: list[tuple[Any, Any, Any]], values: list[Any]) -> bool:
+    """An ``ApplyCall`` is emitted unless it has keys and none of them is set."""
+    return not members or any(value is not None for value in values)
+
+
+async def _render_check(
+    name: str,
+    target: str,
+    members: list[tuple[Any, Any, Any]],
+    values: list[Any],
+    config: ConfigType,
+    parent: str | None,
+    lambda_args: TemplateArgsType,
+) -> str:
+    """Render a boolean check with ``values`` compared against config."""
+    exprs = await _render_values(
+        name, target, members, values, config, parent, lambda_args, compare=True
+    )
+    return target.format(*exprs, parent=parent)
+
+
+def register_apply_condition(
+    name: str, schema: cv.Schema, check: str | ApplyCall, id_key: str = CONF_ID
+) -> None:
+    """Register a condition that is one expression on its parent, with no C++ class.
+
+    ``check`` is applied to the parent: ``"is_playing()"`` becomes ``parent->is_playing()``; an
+    ``ApplyCall`` such as ``ApplyCall("state == {}", ((CONF_STATE, cg.bool_),))`` compares
+    against config values, all of which must be present. Write ``== false`` to negate.
+    A ``cg.std_string`` constant stays in flash on ESP8266 and supports only ``==`` or ``!=``
+    against a ``std::string`` or ``StringRef`` member; other string types are plain literals.
+    Generates one static predicate and an ``ApplyCondition`` templated on it.
+    """
+    call = check if isinstance(check, ApplyCall) else ApplyCall(check)
+    members = _default_std_string(call.members, flash_compare)
+    _check_key_in_schema(name, schema, id_key)
+    for conf_key, _, _ in members:
+        _check_key_in_schema(name, schema, conf_key)
+
+    async def builder(
+        config: ConfigType,
+        condition_id: ID,
+        template_arg: cg.TemplateArguments,
+        args: TemplateArgsType,
+    ) -> MockObj:
+        parent = await _apply_parent(config, id_key)
+        lambda_args = _apply_lambda_args(args)
+        values = _apply_values(config, members)
+        check = await _render_check(
+            name, call.target, members, values, config, parent, lambda_args
+        )
+        return _apply_function(
+            condition_id,
+            cg.bool_,
+            template_arg,
+            lambda_args,
+            [f"return {parent}->{check};"],
+        )
+
+    register_condition(name, ApplyCondition, schema)(builder)
+
 
 def validate_potentially_and_condition(value):
     if isinstance(value, list):
@@ -243,54 +740,22 @@ XorCondition = cg.esphome_ns.class_("XorCondition", Condition)
 
 
 @register_condition("and", AndCondition, validate_condition_list)
-async def and_condition_to_code(
-    config: ConfigType,
-    condition_id: ID,
-    template_arg: cg.TemplateArguments,
-    args: TemplateArgsType,
-) -> MockObj:
-    conditions = await build_condition_list(config, template_arg, args)
-    return cg.new_Pvariable(
-        condition_id, cg.TemplateArguments(len(conditions), *template_arg), conditions
-    )
-
-
-@register_condition("or", OrCondition, validate_condition_list)
-async def or_condition_to_code(
-    config: ConfigType,
-    condition_id: ID,
-    template_arg: cg.TemplateArguments,
-    args: TemplateArgsType,
-) -> MockObj:
-    conditions = await build_condition_list(config, template_arg, args)
-    return cg.new_Pvariable(
-        condition_id, cg.TemplateArguments(len(conditions), *template_arg), conditions
-    )
-
-
 @register_condition("all", AndCondition, validate_condition_list)
-async def all_condition_to_code(
-    config: ConfigType,
-    condition_id: ID,
-    template_arg: cg.TemplateArguments,
-    args: TemplateArgsType,
-) -> MockObj:
-    conditions = await build_condition_list(config, template_arg, args)
-    return cg.new_Pvariable(
-        condition_id, cg.TemplateArguments(len(conditions), *template_arg), conditions
-    )
-
-
+@register_condition("or", OrCondition, validate_condition_list)
 @register_condition("any", OrCondition, validate_condition_list)
-async def any_condition_to_code(
+@register_condition("xor", XorCondition, validate_condition_list)
+async def condition_group_to_code(
     config: ConfigType,
     condition_id: ID,
     template_arg: cg.TemplateArguments,
     args: TemplateArgsType,
 ) -> MockObj:
     conditions = await build_condition_list(config, template_arg, args)
+    # A group of one is that condition for and, or and xor; skip the wrapper.
+    if len(conditions) == 1:
+        return conditions[0]
     return cg.new_Pvariable(
-        condition_id, cg.TemplateArguments(len(conditions), *template_arg), conditions
+        condition_id, cg.TemplateArguments(len(conditions), *template_arg), *conditions
     )
 
 
@@ -305,19 +770,6 @@ async def not_condition_to_code(
     return cg.new_Pvariable(condition_id, template_arg, condition)
 
 
-@register_condition("xor", XorCondition, validate_condition_list)
-async def xor_condition_to_code(
-    config: ConfigType,
-    condition_id: ID,
-    template_arg: cg.TemplateArguments,
-    args: TemplateArgsType,
-) -> MockObj:
-    conditions = await build_condition_list(config, template_arg, args)
-    return cg.new_Pvariable(
-        condition_id, cg.TemplateArguments(len(conditions), *template_arg), conditions
-    )
-
-
 @register_condition("lambda", LambdaCondition, cv.returning_lambda)
 async def lambda_condition_to_code(
     config: ConfigType,
@@ -359,28 +811,15 @@ async def for_condition_to_code(
     return var
 
 
-@register_condition(
+register_apply_condition(
     "component.is_idle",
-    LambdaCondition,
     maybe_simple_id(
         {
             cv.Required(CONF_ID): cv.use_id(cg.Component),
         }
     ),
+    "is_idle()",
 )
-async def component_is_idle_condition_to_code(
-    config: ConfigType,
-    condition_id: ID,
-    template_arg: cg.TemplateArguments,
-    args: TemplateArgsType,
-) -> MockObj:
-    comp = await cg.get_variable(config[CONF_ID])
-    lambda_ = await cg.process_lambda(
-        Lambda(f"return {comp}->is_idle();"), args, return_type=bool
-    )
-    return new_lambda_pvariable(
-        condition_id, lambda_, StatelessLambdaCondition, template_arg
-    )
 
 
 @register_action(
@@ -432,11 +871,13 @@ async def if_action_to_code(
     condition = await build_condition(config[cond_conf], template_arg, args)
     var = cg.new_Pvariable(action_id, if_template_arg, condition)
     if CONF_THEN in config:
-        actions = await build_action_list(config[CONF_THEN], template_arg, args)
-        cg.add(var.add_then(actions))
+        for action in await build_action_list(config[CONF_THEN], template_arg, args):
+            cg.add(var.add_then_action(action))
+        cg.add(var.finish_then())
     if has_else:
-        actions = await build_action_list(config[CONF_ELSE], template_arg, args)
-        cg.add(var.add_else(actions))
+        for action in await build_action_list(config[CONF_ELSE], template_arg, args):
+            cg.add(var.add_else_action(action))
+        cg.add(var.finish_else())
     return var
 
 
@@ -459,8 +900,9 @@ async def while_action_to_code(
 ) -> MockObj:
     condition = await build_condition(config[CONF_CONDITION], template_arg, args)
     var = cg.new_Pvariable(action_id, template_arg, condition)
-    actions = await build_action_list(config[CONF_THEN], template_arg, args)
-    cg.add(var.add_then(actions))
+    for action in await build_action_list(config[CONF_THEN], template_arg, args):
+        cg.add(var.add_then_action(action))
+    cg.add(var.finish_then())
     return var
 
 
@@ -489,7 +931,9 @@ async def repeat_action_to_code(
         cg.TemplateArguments(cg.uint32, *template_arg.args),
         [(cg.uint32, "iteration"), *args],
     )
-    cg.add(var.add_then(actions))
+    for action in actions:
+        cg.add(var.add_then_action(action))
+    cg.add(var.finish_then())
     return var
 
 
@@ -534,44 +978,20 @@ async def lambda_action_to_code(
     return new_lambda_pvariable(action_id, lambda_, StatelessLambdaAction, template_arg)
 
 
-@register_action(
+register_simple_action(
     "component.update",
     UpdateComponentAction,
-    maybe_simple_id(
-        {
-            cv.Required(CONF_ID): cv.use_id(cg.PollingComponent),
-        }
-    ),
+    maybe_simple_id({cv.Required(CONF_ID): cv.use_id(cg.PollingComponent)}),
     synchronous=True,
 )
-async def component_update_action_to_code(
-    config: ConfigType,
-    action_id: ID,
-    template_arg: cg.TemplateArguments,
-    args: TemplateArgsType,
-) -> MockObj:
-    comp = await cg.get_variable(config[CONF_ID])
-    return cg.new_Pvariable(action_id, template_arg, comp)
 
 
-@register_action(
+register_simple_action(
     "component.suspend",
     SuspendComponentAction,
-    maybe_simple_id(
-        {
-            cv.Required(CONF_ID): cv.use_id(cg.PollingComponent),
-        }
-    ),
+    maybe_simple_id({cv.Required(CONF_ID): cv.use_id(cg.PollingComponent)}),
     synchronous=True,
 )
-async def component_suspend_action_to_code(
-    config: ConfigType,
-    action_id: ID,
-    template_arg: cg.TemplateArguments,
-    args: TemplateArgsType,
-) -> MockObj:
-    comp = await cg.get_variable(config[CONF_ID])
-    return cg.new_Pvariable(action_id, template_arg, comp)
 
 
 @register_action(
@@ -649,30 +1069,141 @@ def has_non_synchronous_actions(actions: ConfigType) -> bool:
     Non-synchronous actions (delay, wait_until, script.wait, etc.) store
     trigger args for later execution, making non-owning types like StringRef
     unsafe.
+
+    Accepts an action list, a single action, or an automation. Only the keys of
+    action entries are looked up as action names; the options of an action are
+    only searched for nested action lists (``then:``, ``else:``, ...), so an
+    option that shares a name with an action, such as the ``delay:`` option of
+    ``speaker_source.set_playlist_delay``, is not mistaken for that action.
     """
     if isinstance(actions, list):
         return any(has_non_synchronous_actions(item) for item in actions)
     if isinstance(actions, dict):
-        for key in actions:
+        for key, options in actions.items():
             if key in ACTION_REGISTRY and not ACTION_REGISTRY[key].synchronous:
                 return True
-        return any(
-            has_non_synchronous_actions(v)
-            for v in actions.values()
-            if isinstance(v, (list, dict))
-        )
+            if _options_have_non_synchronous_actions(options):
+                return True
     return False
 
 
+def _options_have_non_synchronous_actions(options: Any) -> bool:
+    """Search an action's options for nested action lists, without treating option keys as actions."""
+    if isinstance(options, list):
+        return has_non_synchronous_actions(options)
+    if isinstance(options, dict):
+        return any(_options_have_non_synchronous_actions(v) for v in options.values())
+    return False
+
+
+def validate_no_deferring_actions(
+    context: str, data: str = "the trigger data"
+) -> Callable[[ConfigType], ConfigType]:
+    """Return a validator that rejects deferring actions in a validated automation.
+
+    Use it for triggers whose arguments only live while the callback runs (views into a reused
+    buffer, a JSON document freed on return, ...): deferring actions keep the arguments for later.
+
+    :param context: Where the automation is, for the error message, e.g. ``"on_json and on_data"``.
+    :param data: What is only valid while the automation runs, for the error message.
+    """
+
+    def validator(value: ConfigType) -> ConfigType:
+        if has_non_synchronous_actions(value):
+            raise cv.Invalid(
+                f"Deferring actions (delay, wait_until, script.wait, ...) are not allowed in "
+                f"{context}: {data} is only valid while the automation runs. Copy what you need "
+                "into globals first, then defer in a separate script or automation."
+            )
+        return value
+
+    return validator
+
+
+def validate_synchronous_automation(
+    context: str,
+    data: str = "the trigger data",
+    extra_schema=None,
+    extra_validators=None,
+    single: bool = False,
+) -> cv.All:
+    """``validate_automation()`` that also rejects deferring actions.
+
+    See ``validate_no_deferring_actions()`` for ``context`` and ``data``; the other parameters are
+    passed to ``validate_automation()``.
+    """
+    return cv.All(
+        validate_automation(
+            extra_schema=extra_schema,
+            extra_validators=extra_validators,
+            single=single,
+        ),
+        validate_no_deferring_actions(context, data),
+    )
+
+
+async def _new_automation(
+    args: TemplateArgsType, config: ConfigType, *ctor_args: MockObj
+) -> MockObj:
+    """Create the Automation for ``config`` with its actions."""
+    templ = cg.TemplateArguments(*(arg[0] for arg in args))
+    obj = cg.new_Pvariable(config[CONF_AUTOMATION_ID], templ, *ctor_args)
+    actions = await build_action_list(config[CONF_THEN], templ, args)
+    for action in actions:
+        cg.add(obj.add_action(action))
+    return obj
+
+
 async def build_automation(
     trigger: MockObj, args: TemplateArgsType, config: ConfigType
 ) -> MockObj:
-    arg_types = [arg[0] for arg in args]
-    templ = cg.TemplateArguments(*arg_types)
-    obj = cg.new_Pvariable(config[CONF_AUTOMATION_ID], templ, trigger)
-    actions = await build_action_list(config[CONF_THEN], templ, args)
-    cg.add(obj.add_actions(actions))
-    return obj
+    return await _new_automation(args, config, trigger)
+
+
+async def build_trigger_callback(
+    args: TemplateArgsType,
+    config: ConfigType,
+    params: TemplateArgsType,
+    forward: Sequence[str | Expression] | None = None,
+    when: str | ApplyCall | None = None,
+    parent: MockObj | None = None,
+) -> LambdaExpression:
+    """Build the Automation for ``config`` and return a stateless callback that triggers it.
+
+    ``params`` are the parent callback's parameters, ``forward`` the expressions passed to
+    ``trigger()`` (default: the parameter names; write the parent as ``parent_ref(var)``),
+    ``when`` a filter the callback returns early on, skipped like any ``ApplyCall`` when none
+    of its keys is set. ``when`` may name ``parent`` as ``{parent}``, e.g.
+    ``"{parent}->is_fully_open()"``.
+    """
+    members: list[tuple[Any, Any, Any]] = []
+    if when is not None:
+        call = when if isinstance(when, ApplyCall) else ApplyCall(when)
+        members = call.members
+        if parent is None and call.names_parent:
+            raise ValueError(f"trigger filter {call.target!r} names {{parent}}")
+    obj = await _new_automation(args, config)
+    lambda_args = _apply_lambda_args(params)
+    statements: list[str] = []
+    if when is not None:
+        values = _apply_values(config, members)
+        if _apply_call_active(members, values):
+            check = await _render_check(
+                "trigger filter",
+                call.target,
+                members,
+                values,
+                config,
+                None if parent is None else str(parent_ref(parent)),
+                lambda_args,
+            )
+            statements.append(f"if (!({check}))\n  return;")
+    if forward is None:
+        forward = [name for _, name in params]
+    statements.append(f"{parent_ref(obj)}->trigger({', '.join(map(str, forward))});")
+    return LambdaExpression(
+        ["\n".join(statements)], lambda_args, capture="", return_type=cg.void
+    )
 
 
 async def build_callback_automation(
@@ -681,6 +1212,9 @@ async def build_callback_automation(
     args: TemplateArgsType,
     config: ConfigType,
     forwarder: MockObj | MockObjClass | None = None,
+    params: TemplateArgsType | None = None,
+    forward: Sequence[str | Expression] | None = None,
+    when: str | ApplyCall | None = None,
 ) -> None:
     """Build an Automation and register it as a callback on the parent.
 
@@ -692,6 +1226,9 @@ async def build_callback_automation(
     pointer-sized (single Automation* field) to fit inline in Callback::ctx_
     and avoid heap allocation.
 
+    With ``params``, ``forward`` or ``when`` the callback is instead the stateless
+    lambda of ``build_trigger_callback``; ``forwarder`` cannot be combined with them.
+
     :param parent: The component object (e.g., button, sensor).
     :param callback_method: Name of the callback method (e.g., "add_on_press_callback").
     :param args: Automation template args as list of (type, name) tuples.
@@ -700,22 +1237,56 @@ async def build_callback_automation(
         TriggerForwarder<Ts...>. Pass any struct type whose aggregate init takes
         a single Automation pointer (e.g., TriggerOnTrueForwarder).
     """
-    arg_types = [arg[0] for arg in args]
-    templ = cg.TemplateArguments(*arg_types)
-    obj = cg.new_Pvariable(config[CONF_AUTOMATION_ID], templ)
-    actions = await build_action_list(config[CONF_THEN], templ, args)
-    cg.add(obj.add_actions(actions))
+    if params is not None or forward is not None or when is not None:
+        if forwarder is not None:
+            raise ValueError(
+                "forwarder cannot be combined with params, forward or when"
+            )
+        callback = await build_trigger_callback(
+            args, config, args if params is None else params, forward, when, parent
+        )
+        cg.add(getattr(parent, callback_method)(callback))
+        return
+    obj = await _new_automation(args, config)
     # Use template forwarder structs for deduplication. The compiler generates
     # one operator() per forwarder type; different automation pointers are just
     # data in the struct.
     if forwarder is None:
-        forwarder = TriggerForwarder.template(templ)
+        forwarder = TriggerForwarder.template(*(arg[0] for arg in args))
     # RawExpression for aggregate init — both forwarder and obj are codegen
     # MockObjs (not user input), and there's no Expression type for positional
     # aggregate initialization (StructInitializer uses named fields).
     cg.add(getattr(parent, callback_method)(cg.RawExpression(f"{forwarder}{{{obj}}}")))
 
 
+async def build_parent_callback_automation(
+    parent: MockObj, callback_method: str, arg: tuple[Any, str], config: ConfigType
+) -> None:
+    """Register an Automation that receives ``parent`` from a callback that carries nothing.
+
+    ``arg`` is the automation's ``(type, name)``, e.g. ``(Fan.operator("ptr"), "x")``.
+    """
+    await build_callback_automation(
+        parent, callback_method, [arg], config, params=[], forward=[parent_ref(parent)]
+    )
+
+
+async def build_trigger_automations(
+    parent: MockObj | None,
+    config: ConfigType,
+    entries: tuple[tuple[str, TemplateArgsType], ...],
+) -> None:
+    """Instantiate each entry's Trigger class, with ``parent`` when given, and build its automations.
+
+    ``entries`` are ``(conf_key, args)`` pairs; the class comes from the entry's ``CONF_TRIGGER_ID``.
+    """
+    ctor_args = () if parent is None else (parent,)
+    for conf_key, args in entries:
+        for conf in config.get(conf_key, []):
+            trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], *ctor_args)
+            await build_automation(trigger, args, conf)
+
+
 @dataclass(frozen=True, slots=True)
 class CallbackAutomation:
     """A single callback automation entry for build_callback_automations."""
@@ -724,6 +1295,9 @@ class CallbackAutomation:
     callback_method: str
     args: TemplateArgsType = field(default_factory=list)
     forwarder: MockObj | MockObjClass | None = None
+    params: TemplateArgsType | None = None
+    forward: Sequence[str | Expression] | None = None
+    when: str | ApplyCall | None = None
 
 
 async def build_callback_automations(
@@ -745,4 +1319,7 @@ async def build_callback_automations(
                 entry.args,
                 conf,
                 forwarder=entry.forwarder,
+                params=entry.params,
+                forward=entry.forward,
+                when=entry.when,
             )

esphome/build_gen/build_tool.py

@@ -0,0 +1,108 @@
+"""Tiny cross-platform build steps invoked from the generated ninja file.
+
+Plain script (not ``python -m``): it runs from ninja with whatever Python
+started esphome and must not depend on the package being importable.
+
+Subcommands:
+    ar <ar-binary> <archive> <rspfile>   remove stale archive, then ``ar rcs``
+    copy <src> <dst>                     copy a file
+
+The ar rspfile carries one object path per line (the generating rule must
+use ``$in_newline``, never ``$in``).
+"""
+
+from pathlib import Path
+import shutil
+import subprocess
+import sys
+
+
+def _read_rspfile(rspfile: str) -> list[str]:
+    r"""The object paths listed in ``rspfile``, unquoted.
+
+    GNU ar treats backslashes in response files as escapes (corrupts
+    Windows paths), so the caller expands the list into argv; strip the
+    simple surrounding quote ninja adds to special paths, then undo
+    ninja's POSIX escape for an embedded quote ('a'\\''b.o' -> a'b.o).
+    """
+    return [
+        line[1:-1].replace("'\\''", "'")
+        if len(line) >= 2 and line[0] == line[-1] and line[0] in "'\""
+        else line
+        for line in Path(rspfile).read_text(encoding="utf-8").splitlines()
+        if line
+    ]
+
+
+def _run_ar(ar: str, archive: str, rspfile: str) -> int:
+    # Remove first: ``ar rcs`` replaces members but never drops ones whose
+    # source was removed from the build, which would leak stale objects.
+    Path(archive).unlink(missing_ok=True)
+    objects = _read_rspfile(rspfile)
+    if not objects:
+        # An empty archive would "succeed" here and fail far away at link
+        print(f"ar: no objects listed in {rspfile} for {archive}", file=sys.stderr)
+        return 1
+    # Batch by argv length: expanding the rspfile gives back the Windows
+    # 32767-char command-line limit it existed to avoid. "rcs" creates,
+    # "qs" appends; the s keeps the symbol index explicit on every ar.
+    op = "rcs"
+    ok = False
+    try:
+        while objects:
+            batch = [objects.pop(0)]
+            batch_len = len(batch[0])
+            while objects and batch_len + len(objects[0]) < 25000:
+                batch_len += len(objects[0]) + 1
+                batch.append(objects.pop(0))
+            rc = subprocess.run(
+                [ar, op, archive, *batch], check=False, close_fds=False
+            ).returncode
+            if rc != 0:
+                return rc
+            op = "qs"
+        ok = True
+        return 0
+    finally:
+        if not ok:
+            # Any failure (bad exit, missing ar binary, interrupt) must not
+            # leave a truncated archive behind
+            Path(archive).unlink(missing_ok=True)
+
+
+def _run_copy(src: str, dst: str) -> int:
+    try:
+        shutil.copyfile(src, dst)
+    except OSError as err:
+        # Never leave a partially written output (e.g. a firmware image);
+        # SameFileError means dst IS src, where unlinking destroys the input
+        if not isinstance(err, shutil.SameFileError):
+            Path(dst).unlink(missing_ok=True)
+        print(f"copy: {src} -> {dst} failed: {err}", file=sys.stderr)
+        return 1
+    return 0
+
+
+# mode -> (handler, expected operand count); surplus argv means a
+# mis-specified ninja rule and must error, not silently drop operands
+_MODES = {"ar": (_run_ar, 3), "copy": (_run_copy, 2)}
+
+
+def main() -> int:
+    mode = sys.argv[1] if len(sys.argv) > 1 else ""
+    if entry := _MODES.get(mode):
+        handler, argc = entry
+        args = sys.argv[2:]
+        if len(args) != argc:
+            print(
+                f"build_tool {mode}: expected {argc} arguments, got {len(args)}",
+                file=sys.stderr,
+            )
+            return 1
+        return handler(*args)
+    print(f"unknown build_tool mode: {mode}", file=sys.stderr)
+    return 1
+
+
+if __name__ == "__main__":  # pragma: no cover
+    sys.exit(main())

esphome/build_gen/espidf.py

@@ -1,17 +1,29 @@
 """ESP-IDF direct build generator for ESPHome."""
 
 import json
+import logging
 from pathlib import Path
+import re
+import textwrap
 
-from esphome.components.esp32 import get_esp32_variant, idf_version
+from esphome.build_helpers import pch
+from esphome.components.esp32 import (
+    get_esp32_variant,
+    get_excluded_builtin_components,
+    get_managed_component_require_names,
+    idf_version,
+)
 import esphome.config_validation as cv
 from esphome.core import CORE
+from esphome.espidf import variant_to_idf_target
 from esphome.framework_helpers import (
     get_project_compile_flags,
     get_project_cxx_compile_flags,
     get_project_link_flags,
 )
-from esphome.helpers import mkdir_p, write_file_if_changed
+from esphome.helpers import get_bool_env, mkdir_p, write_file_if_changed
+
+_LOGGER = logging.getLogger(__name__)
 
 # Replaces the IDF default C++ standard (-std=gnu++2b appended to
 # CXX_COMPILE_OPTIONS by project.cmake's __build_init) with the one set via
@@ -24,13 +36,91 @@ list(FILTER esphome_cxx_compile_options EXCLUDE REGEX "^-std=")
 list(APPEND esphome_cxx_compile_options "-std={standard}")
 idf_build_set_property(CXX_COMPILE_OPTIONS "${{esphome_cxx_compile_options}}")"""
 
+# Drops the app archive from ldgen's inputs so app-only edits skip the
+# sections.ld regeneration. Safe: no mapping fragment references it
+# (run_compile re-checks each build). Filters only the top-level call;
+# the prior definition stays reachable with an underscore prefix.
+_LDGEN_OVERRIDE = """\
+if(COMMAND __ldgen_get_lib_deps_of_target)
+    set_property(GLOBAL PROPERTY ESPHOME_LDGEN_ARMED 1)
+    function(__ldgen_get_lib_deps_of_target target out_list_var)
+        if(NOT COMMAND ___ldgen_get_lib_deps_of_target)
+            message(FATAL_ERROR "ESPHome ldgen override lost the original "
+                "implementation; set ESPHOME_LDGEN_FULL_DEPS=1 and rebuild.")
+        endif()
+        ___ldgen_get_lib_deps_of_target(${target} ${out_list_var})
+        if(out_list_var STREQUAL "ldgen_libraries")
+            set_property(GLOBAL PROPERTY ESPHOME_LDGEN_FILTERED 1)
+            list(LENGTH ${out_list_var} esphome_ldgen_before)
+            list(REMOVE_ITEM ${out_list_var} idf::src __idf_src)
+            list(LENGTH ${out_list_var} esphome_ldgen_after)
+            if(esphome_ldgen_before EQUAL esphome_ldgen_after)
+                message(@SEVERITY@ "ESPHome ldgen app archive exclusion matched "
+                    "nothing; app edits will regenerate sections.ld.")
+            endif()
+        endif()
+        set(${out_list_var} "${${out_list_var}}" PARENT_SCOPE)
+    endfunction()
+else()
+    message(@MISSING@ "ESPHome ldgen override target not found; "
+        "app edits will regenerate sections.ld.")
+endif()"""
+
+# lwip sources that compile to empty objects with the option off (their own
+# #if guard). (option, regex valid for both Python and CMake); a source is
+# only dropped when its option is defined and off, so a renamed option
+# keeps it.
+LWIP_EMPTY_SOURCES: tuple[tuple[str, str], ...] = (
+    ("CONFIG_LWIP_PPP_SUPPORT", "/netif/ppp/"),
+    ("CONFIG_LWIP_IPV6", "/core/ipv6/"),
+    ("CONFIG_LWIP_AUTOIP", "/core/ipv4/autoip[.]c$"),
+    ("CONFIG_LWIP_STATS", "/core/stats[.]c$"),
+)
+# Drift guard only: keep every lwip source.
+LWIP_FULL_SOURCES_ENV = "ESPHOME_LWIP_FULL_SOURCES"
+
+# Drops the empty objects after project(), once the lwip target exists.
+_LWIP_EMPTY_SOURCES_FILTER = f"""\
+idf_build_get_property(esphome_build_components BUILD_COMPONENTS)
+if(lwip IN_LIST esphome_build_components AND NOT DEFINED ENV{{{LWIP_FULL_SOURCES_ENV}}})
+    idf_component_get_property(esphome_lwip_lib lwip COMPONENT_LIB)
+    get_target_property(esphome_lwip_srcs ${{esphome_lwip_lib}} SOURCES)
+@FILTERS@
+    set_property(TARGET ${{esphome_lwip_lib}} PROPERTY SOURCES ${{esphome_lwip_srcs}})
+endif()"""
+
+
+def lwip_empty_source_gate(option: str, regex: str) -> str:
+    return (
+        f"    if(DEFINED {option} AND NOT {option})\n"
+        f'        list(FILTER esphome_lwip_srcs EXCLUDE REGEX "{regex}")\n'
+        "    endif()"
+    )
+
+
+def _lwip_empty_sources_filter() -> str:
+    gates = "\n".join(lwip_empty_source_gate(*entry) for entry in LWIP_EMPTY_SOURCES)
+    return _LWIP_EMPTY_SOURCES_FILTER.replace("@FILTERS@", gates)
+
+
+# Runs after project() so the walk has happened; catches the remaining
+# silent path where the top-level out-var was renamed.
+_LDGEN_OVERRIDE_CHECK = """\
+get_property(esphome_ldgen_armed GLOBAL PROPERTY ESPHOME_LDGEN_ARMED)
+get_property(esphome_ldgen_filtered GLOBAL PROPERTY ESPHOME_LDGEN_FILTERED)
+if(esphome_ldgen_armed AND NOT esphome_ldgen_filtered)
+    message(@SEVERITY@ "ESPHome ldgen override never filtered the app "
+        "archive; app edits will regenerate sections.ld.")
+endif()"""
+
 
 def get_available_components() -> list[str] | None:
-    """Get list of built-in ESP-IDF components from project_description.json.
+    """List the built-in ESP-IDF components from ``project_description.json``.
 
-    Excludes ``src``, IDF-managed components (``managed_components/``), and
-    converted PIO libs (``pio_components/``). Returns ``None`` if the build
-    dir or ``project_description.json`` isn't ready yet.
+    Only components below its ``idf_path/components`` count, which leaves out
+    ``src``, IDF-managed components, converted PIO libs and project local
+    ones such as the Arduino ``component_stubs``. Returns ``None`` if the
+    build dir or ``project_description.json`` isn't ready yet.
     """
     if CORE.build_path is None:
         return None
@@ -41,45 +131,157 @@ def get_available_components() -> list[str] | None:
     try:
         with project_desc.open(encoding="utf-8") as f:
             data = json.load(f)
-
-        component_info = data.get("build_component_info", {})
-
-        result = []
-        for name, info in component_info.items():
-            # Exclude our own src component
-            if name == "src":
-                continue
-
-            # Exclude IDF-managed and converted-PIO components (external).
-            comp_dir = info.get("dir", "")
-            if "managed_components" in comp_dir or "pio_components" in comp_dir:
-                continue
-
-            result.append(name)
-
-        return result
-    except (json.JSONDecodeError, OSError):
+        root = (Path(data["idf_path"]) / "components").resolve()
+        result = [
+            name
+            for name, info in data.get("build_component_info", {}).items()
+            if (comp_dir := info.get("dir"))
+            and Path(comp_dir).resolve().is_relative_to(root)
+        ]
+    except (json.JSONDecodeError, KeyError, OSError) as err:
+        _LOGGER.debug("Could not read %s: %s", project_desc, err)
         return None
+    if not result:
+        _LOGGER.warning("No ESP-IDF components found under %s", root)
+    return result
 
 
 def has_discovered_components() -> bool:
-    """Check if we have discovered components from a previous configure."""
-    return get_available_components() is not None
+    """Check if a previous configure discovered any built-in components."""
+    return bool(get_available_components())
 
 
-def get_project_cmakelists(minimal: bool = False) -> str:
+def _cmake_quote(value: str) -> str:
+    """Quote a cmake arg value for a set() line. add_cmake_arg rejects
+    whitespace, quotes, and '$', so only backslashes need escaping."""
+    escaped = value.replace("\\", "\\\\")
+    return f'"{escaped}"'
+
+
+# CONFIG_APP_BUILD_BOOTLOADER is hidden and force-selected, so it can only be
+# cleared at the CMake level (the same state IDF's RAM-app build type uses).
+# The macro is IDF's __build_process_project_includes plus a few added lines;
+# the flag is ignored and the bootloader builds as usual if IDF changes it.
+IDF_BOOTLOADER_OVERRIDE = """\
+# ESPHome bootloader skip switch; see esphome/espidf/toolchain.py.
+if(ESPHOME_SKIP_BOOTLOADER)
+    macro(__build_process_project_includes)
+        idf_build_get_property(sdkconfig_cmake SDKCONFIG_CMAKE)
+        include(${sdkconfig_cmake})
+        set(CONFIG_APP_BUILD_BOOTLOADER "")
+        # bt's CMakeLists reads the lowercase idf_target that the (now
+        # skipped) bootloader project_include leaks; keep it defined, or
+        # its empty TARGET_SRC_NAME sends file(GLOB_RECURSE) across /.
+        idf_build_get_property(idf_target IDF_TARGET)
+        # partition_table's V1 ECDSA signing reads this key, which the
+        # skipped bootloader project_include also sets.
+        get_filename_component(SECURE_BOOT_SIGNING_KEY "${CONFIG_SECURE_BOOT_SIGNING_KEY}" ABSOLUTE BASE_DIR "${project_dir}")
+        idf_build_get_property(build_properties __BUILD_PROPERTIES)
+        foreach(build_property ${build_properties})
+            idf_build_get_property(val ${build_property})
+            set(${build_property} "${val}")
+        endforeach()
+        idf_build_get_property(build_component_targets __BUILD_COMPONENT_TARGETS)
+        foreach(component_target ${build_component_targets})
+            __component_get_property(dir ${component_target} COMPONENT_DIR)
+            __component_get_property(_name ${component_target} COMPONENT_NAME)
+            set(COMPONENT_NAME ${_name})
+            set(COMPONENT_DIR ${dir})
+            set(COMPONENT_PATH ${dir})
+            if(EXISTS ${COMPONENT_DIR}/project_include.cmake)
+                include(${COMPONENT_DIR}/project_include.cmake)
+            endif()
+        endforeach()
+    endmacro()
+endif()
+"""
+
+# The lines the override adds to IDF's macro; idf_macro_matches() below
+# strips them before comparing with the live macro.
+BOOTLOADER_OVERRIDE_ADDED_LINES = (
+    'set(CONFIG_APP_BUILD_BOOTLOADER "")',
+    "idf_build_get_property(idf_target IDF_TARGET)",
+    (
+        "get_filename_component(SECURE_BOOT_SIGNING_KEY"
+        ' "${CONFIG_SECURE_BOOT_SIGNING_KEY}" ABSOLUTE BASE_DIR "${project_dir}")'
+    ),
+)
+
+_MACRO = re.compile(
+    r"macro\(__build_process_project_includes\)(.*?)endmacro\(\)", re.DOTALL
+)
+
+
+def _normalized_macro(text: str) -> list[str] | None:
+    """The macro body as comment-free, whitespace-collapsed lines."""
+    if (match := _MACRO.search(text)) is None:
+        return None
+    return [
+        re.sub(r"\s+", " ", line)
+        for raw in match.group(1).splitlines()
+        if (line := raw.split("#", 1)[0].strip())
+    ]
+
+
+_EXPECTED_MACRO = [
+    line
+    for line in _normalized_macro(IDF_BOOTLOADER_OVERRIDE)
+    if line not in BOOTLOADER_OVERRIDE_ADDED_LINES
+]
+
+
+def idf_macro_matches(idf_path: Path) -> bool:
+    """Whether IDF's macro still matches the copy the override replays."""
+    build_cmake = idf_path / "tools" / "cmake" / "build.cmake"
+    live = _normalized_macro(build_cmake.read_text(encoding="utf-8"))
+    return live == _EXPECTED_MACRO
+
+
+def _cmake_args_for_write(minimal: bool) -> dict[str, str]:
+    """The cg.add_cmake_arg() values for one project write.
+
+    The discovery (minimal) write lets every built-in component register so
+    the list it finds, cached per target, serves any exclusion set; the full
+    write drops the excluded names from that list and passes all of them to
+    IDF. Names outside the framework's components directory (managed
+    components) stay excluded on the discovery write too, since the list
+    only holds built-in ones. A checkout supplied through IDF_PATH caches
+    nothing, so its discovery keeps every exclusion.
+    """
+    from esphome.espidf.toolchain import _esphome_manages_idf, _get_idf_path
+
+    args = dict(CORE.cmake_args)
+    if (
+        not minimal
+        or not _esphome_manages_idf()
+        or not (excluded := args.get("EXCLUDE_COMPONENTS"))
+    ):
+        return args
+    root = _get_idf_path() / "components"
+    outside = [name for name in excluded.split(";") if not (root / name).is_dir()]
+    if outside:
+        args["EXCLUDE_COMPONENTS"] = ";".join(outside)
+    else:
+        del args["EXCLUDE_COMPONENTS"]
+    return args
+
+
+def get_project_cmakelists(
+    minimal: bool = False, builtin_components: list[str] | None = None
+) -> str:
     """Generate the top-level CMakeLists.txt for ESP-IDF project.
 
     When ``minimal`` is true, omit ``ESPHOME_PROJECT_BUILTIN_COMPONENTS``
     since ``project_description.json`` may be stale on the first write.
+    ``builtin_components`` supplies the discovered list (from the cache)
+    instead of reading it from ``project_description.json``.
     """
-    # Get IDF target from ESP32 variant (e.g., ESP32S3 -> esp32s3)
-    variant = get_esp32_variant()
-    idf_target = variant.lower().replace("-", "")
+    idf_target = variant_to_idf_target(get_esp32_variant())
 
-    # esp_idf_size 2.x (bundled with IDF >=6.0) made NG the default and
-    # removed the --ng flag; on 1.x (IDF 5.5) --ng is required to get
-    # --format=raw because the legacy mode doesn't support it.
+    # esp_idf_size 2.x (IDF >=6.0) made NG the default and removed --ng;
+    # 1.x (IDF 5.5) needs --ng for --format=json2. 1.x json2 also lacks
+    # total_size, hence the ELF fallback in espidf/size_summary.py; both
+    # go away together when 1.x support is dropped.
     size_ng_flag = "--ng" if idf_version() < cv.Version(6, 0, 0) else ""
 
     # Project-wide compile options: -D defines and -W warning flags (skip
@@ -109,6 +311,30 @@ def get_project_cmakelists(minimal: bool = False) -> str:
         else ""
     )
 
+    # Stops the ~3s sections.ld regeneration on app-only edits; see
+    # _LDGEN_OVERRIDE. ESPHOME_LDGEN_FULL_DEPS=1 restores stock behavior;
+    # ESPHOME_LDGEN_STRICT=1 (CI) fails the configure when an IDF bump
+    # breaks the override instead of degrading to stock deps.
+    if get_bool_env("ESPHOME_LDGEN_FULL_DEPS"):
+        ldgen_override = ""
+        ldgen_override_check = ""
+    else:
+        strict = get_bool_env("ESPHOME_LDGEN_STRICT")
+        severity = "FATAL_ERROR" if strict else "WARNING"
+        missing = "FATAL_ERROR" if strict else "STATUS"
+        ldgen_override = _LDGEN_OVERRIDE.replace("@SEVERITY@", severity).replace(
+            "@MISSING@", missing
+        )
+        ldgen_override_check = _LDGEN_OVERRIDE_CHECK.replace("@SEVERITY@", severity)
+
+    # CMake variables registered via cg.add_cmake_arg(). Emitted before
+    # include(project.cmake) so values like EXCLUDE_COMPONENTS are already
+    # set when project.cmake seeds the component list.
+    cmake_args = "\n".join(
+        f"set({name} {_cmake_quote(value)})"
+        for name, value in sorted(_cmake_args_for_write(minimal).items())
+    )
+
     # Per-project list exposed as a CMake variable so converted PIO libs
     # can reference ${ESPHOME_PROJECT_MANAGED_COMPONENTS} without baking
     # project-specific names into their cached CMakeLists.
@@ -119,8 +345,6 @@ def get_project_cmakelists(minimal: bool = False) -> str:
     # runs as a separate CMake script invocation that doesn't load the
     # project's top-level CMakeLists; without this, ${ESPHOME_PROJECT_
     # MANAGED_COMPONENTS} in a converted-lib REQUIRES expands to empty).
-    from esphome.components.esp32 import get_managed_component_require_names
-
     managed_components_property = "\n".join(
         f"idf_build_set_property(ESPHOME_PROJECT_MANAGED_COMPONENTS {name} APPEND)"
         for name in get_managed_component_require_names()
@@ -131,12 +355,24 @@ def get_project_cmakelists(minimal: bool = False) -> str:
     # component's REQUIRES including real IDF components). Referenced by
     # src/CMakeLists and by each converted PIO lib's CMakeLists. Skipped
     # on minimal writes because project_description.json may be stale.
+    # Excluded components are dropped here as well: the discovery list
+    # (cached per target) still holds them, and requiring an excluded
+    # component pulls it back into the build (IDF requirement expansion
+    # overrides EXCLUDE_COMPONENTS).
+    # Derived from the EXCLUDE_COMPONENTS cmake arg emitted above so the
+    # two can never disagree within one generated file.
     builtin_components_property = (
         ""
         if minimal
         else "\n".join(
             f"idf_build_set_property(ESPHOME_PROJECT_BUILTIN_COMPONENTS {name} APPEND)"
-            for name in sorted(get_available_components() or [])
+            for name in sorted(
+                set(
+                    builtin_components
+                    if builtin_components is not None
+                    else get_available_components() or []
+                ).difference(CORE.cmake_args.get("EXCLUDE_COMPONENTS", "").split(";"))
+            )
         )
     )
 
@@ -163,8 +399,13 @@ set(CMAKE_NINJA_FORCE_RESPONSE_FILE 1)
 set(IDF_TARGET {idf_target})
 set(EXTRA_COMPONENT_DIRS ${{CMAKE_SOURCE_DIR}}/src)
 
+{cmake_args}
+
 include($ENV{{IDF_PATH}}/tools/cmake/project.cmake)
 
+{IDF_BOOTLOADER_OVERRIDE}
+{ldgen_override}
+
 {cpp_standard_options}
 
 {cxx_compile_options}
@@ -177,12 +418,31 @@ include($ENV{{IDF_PATH}}/tools/cmake/project.cmake)
 
 project({CORE.name})
 
-# Emit raw JSON size data for ESPHome to read post-build.
+{ldgen_override_check}
+
+{_lwip_empty_sources_filter()}
+
+# Emit per-memory-type JSON size data for ESPHome to read post-build.
+# json2 stays small; raw dumps every symbol (~2s on a large map) and
+# this command runs inside the link edge, blocking everything downstream.
+# IDF's size target depends on the map, so ninja has to know the link
+# writes it for size to build in the same run as all. IDF declares the
+# map itself since espressif/esp-idf#19201 (and in cmakev2), and ninja
+# rejects two rules for one output, so declare it here only when IDF has
+# not. add_custom_command(OUTPUT) marks its outputs GENERATED.
+get_source_file_property(esphome_map_declared
+    ${{CMAKE_BINARY_DIR}}/${{CMAKE_PROJECT_NAME}}.map GENERATED)
+if(esphome_map_declared)
+    set(esphome_map_byproducts)
+else()
+    set(esphome_map_byproducts BYPRODUCTS ${{CMAKE_BINARY_DIR}}/${{CMAKE_PROJECT_NAME}}.map)
+endif()
 add_custom_command(
     TARGET ${{CMAKE_PROJECT_NAME}}.elf POST_BUILD
-    COMMAND ${{PYTHON}} -m esp_idf_size {size_ng_flag} --format=raw
+    COMMAND ${{PYTHON}} -m esp_idf_size {size_ng_flag} --format=json2
             -o ${{CMAKE_BINARY_DIR}}/esp_idf_size.json
             ${{CMAKE_PROJECT_NAME}}.map
+    ${{esphome_map_byproducts}}
     WORKING_DIRECTORY ${{CMAKE_BINARY_DIR}}
     VERBATIM
 )
@@ -210,15 +470,27 @@ def get_component_cmakelists() -> str:
 if(CMAKE_SCRIPT_MODE_FILE)
     file(GLOB_RECURSE app_sources
         "${{CMAKE_CURRENT_SOURCE_DIR}}/*.cpp"
+        "${{CMAKE_CURRENT_SOURCE_DIR}}/*.cc"
+        "${{CMAKE_CURRENT_SOURCE_DIR}}/*.cxx"
+        "${{CMAKE_CURRENT_SOURCE_DIR}}/*.c++"
         "${{CMAKE_CURRENT_SOURCE_DIR}}/*.c"
         "${{CMAKE_CURRENT_SOURCE_DIR}}/esphome/*.cpp"
+        "${{CMAKE_CURRENT_SOURCE_DIR}}/esphome/*.cc"
+        "${{CMAKE_CURRENT_SOURCE_DIR}}/esphome/*.cxx"
+        "${{CMAKE_CURRENT_SOURCE_DIR}}/esphome/*.c++"
         "${{CMAKE_CURRENT_SOURCE_DIR}}/esphome/*.c"
     )
 else()
     file(GLOB_RECURSE app_sources CONFIGURE_DEPENDS
         "${{CMAKE_CURRENT_SOURCE_DIR}}/*.cpp"
+        "${{CMAKE_CURRENT_SOURCE_DIR}}/*.cc"
+        "${{CMAKE_CURRENT_SOURCE_DIR}}/*.cxx"
+        "${{CMAKE_CURRENT_SOURCE_DIR}}/*.c++"
         "${{CMAKE_CURRENT_SOURCE_DIR}}/*.c"
         "${{CMAKE_CURRENT_SOURCE_DIR}}/esphome/*.cpp"
+        "${{CMAKE_CURRENT_SOURCE_DIR}}/esphome/*.cc"
+        "${{CMAKE_CURRENT_SOURCE_DIR}}/esphome/*.cxx"
+        "${{CMAKE_CURRENT_SOURCE_DIR}}/esphome/*.c++"
         "${{CMAKE_CURRENT_SOURCE_DIR}}/esphome/*.c"
     )
 endif()
@@ -233,10 +505,75 @@ idf_component_register(
 target_link_options(${{COMPONENT_LIB}} PUBLIC
     {link_opts_str}
 )
+{_pch_cmake_block()}"""
+
+
+# Where CMake puts the .gch of the src component; ccache reads the checksum
+# next to it in place of the .gch
+_PCH_SUM_PATH = "build/esp-idf/src/CMakeFiles/__idf_src.dir/cmake_pch.hxx.gch.sum"
+# Where the Windows gate records its choice
+_PCH_CHOICE_VAR = "ESPHOME_PCH"
+
+
+def _pch_cmake_block() -> str:
+    """The CMake block that precompiles the core headers for the C++ sources
+    of the src component; empty when disabled."""
+    if not pch.pch_enabled():
+        return ""
+    headers = "\n".join(
+        f'    "$<$<COMPILE_LANGUAGE:CXX>:${{CMAKE_CURRENT_SOURCE_DIR}}/{header}>"'
+        for header in pch.PCH_DEFAULT_HEADERS
+    )
+    block = f"""target_precompile_headers(${{COMPONENT_LIB}} PRIVATE
+{headers}
+)"""
+    if not pch.pch_needs_gcc_check():
+        return f"\n# ESPHome precompiled header\n{block}\n"
+    # Before the first configure only CMake knows the compiler version
+    return f"""
+# ESPHome precompiled header, unless GCC bug 14940 keeps it from loading
+if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" AND ({pch.PCH_WINDOWS_CMAKE_OLD_GCC}))
+  message(STATUS "ESPHome: GCC ${{CMAKE_CXX_COMPILER_VERSION}} cannot load a precompiled header on Windows; compiling without it")
+  set({_PCH_CHOICE_VAR} OFF CACHE BOOL "ESPHome precompiled header in use" FORCE)
+else()
+  set({_PCH_CHOICE_VAR} ON CACHE BOOL "ESPHome precompiled header in use" FORCE)
+{textwrap.indent(block, "  ")}
+endif()
 """
 
 
-def write_project(minimal: bool = False) -> None:
+def _read_if_exists(path: Path) -> str:
+    return path.read_text(encoding="utf-8") if path.is_file() else ""
+
+
+def write_pch_checksum() -> None:
+    """Write the checksum ccache uses in place of the .gch: the core headers,
+    the framework version, the sdkconfig and the managed component versions."""
+    from esphome.espidf.toolchain import get_cmake_cache_value
+
+    if not pch.pch_enabled():
+        return
+    # The gate's choice, cached by configure
+    if pch.pch_needs_gcc_check() and get_cmake_cache_value(_PCH_CHOICE_VAR) != "ON":
+        return
+    pch.log_pch_in_use()
+    checksum = pch.pch_checksum(
+        CORE.relative_src_path(),
+        pch.PCH_DEFAULT_HEADERS,
+        (
+            str(idf_version()),
+            _read_if_exists(CORE.relative_build_path(f"sdkconfig.{CORE.name}")),
+            _read_if_exists(CORE.relative_build_path("dependencies.lock")),
+        ),
+    )
+    path = CORE.relative_build_path(_PCH_SUM_PATH)
+    path.parent.mkdir(parents=True, exist_ok=True)
+    write_file_if_changed(path, checksum + "\n")
+
+
+def write_project(
+    minimal: bool = False, builtin_components: list[str] | None = None
+) -> None:
     """Write ESP-IDF project files."""
     mkdir_p(CORE.build_path)
     mkdir_p(CORE.relative_src_path())
@@ -244,7 +581,7 @@ def write_project(minimal: bool = False) -> None:
     # Write top-level CMakeLists.txt
     write_file_if_changed(
         CORE.relative_build_path("CMakeLists.txt"),
-        get_project_cmakelists(minimal=minimal),
+        get_project_cmakelists(minimal=minimal, builtin_components=builtin_components),
     )
 
     # Write component CMakeLists.txt in src/
@@ -252,3 +589,12 @@ def write_project(minimal: bool = False) -> None:
         CORE.relative_src_path("CMakeLists.txt"),
         get_component_cmakelists(),
     )
+
+    # Snapshot the exclusion set so has_outdated_files() can trigger a
+    # reconfigure when it changes. The ESPHOME_PROJECT_BUILTIN_COMPONENTS
+    # property drops excluded names, so re-including one (e.g. a config
+    # gains mqtt) needs a reconfigure to rebuild it from the discovery list.
+    write_file_if_changed(
+        CORE.relative_build_path("exclude_components.esphomeinternal"),
+        ";".join(get_excluded_builtin_components()),
+    )

esphome/build_gen/host.py

@@ -0,0 +1,303 @@
+"""Native ninja build generator for the host platform.
+
+Emits ``build.ninja`` under ``.pioenvs/<name>/``: every source in the
+generated ``src/`` tree plus the resolved registry libraries compiles with
+the machine's compiler and links into ``program``, the name PlatformIO's
+native platform produced. Build flags route the way SCons's ``ParseFlags``
+did under PlatformIO: ``-D``/``-I``/``-std=``/``-W`` shapes reach the
+compile lines only, ``-l``/``-L``/``-Wl,`` the link line only, everything
+else both.
+"""
+
+from __future__ import annotations
+
+from collections.abc import Iterable
+import logging
+import os
+from pathlib import Path
+import subprocess
+import sys
+from typing import TYPE_CHECKING
+
+from esphome.build_helpers.ninja import escape as _e, quote_path as _q, shell_token
+from esphome.build_helpers.ninja_gen import (
+    PATH_ARG_FLAGS,
+    Flag,
+    anchor_path_flag,
+    ar_rule_lines,
+    collect_sources,
+    compile_edges,
+    compile_rule_lines,
+    library_edges,
+    pch_edges,
+    pch_rule_lines,
+    tool_lines,
+)
+from esphome.build_helpers.pch import PCH_DEFAULT_HEADERS, pch_enabled
+from esphome.core import CORE, EsphomeError
+from esphome.framework_helpers import get_project_cxx_compile_flags
+from esphome.helpers import mkdir_p, write_file_if_changed
+from esphome.host.toolchain import PROGRAM_NAME, HostCompilers, find_tool, get_build_dir
+from esphome.platformio.library import lex_build_flags
+
+if TYPE_CHECKING:
+    from esphome.arduino.library import ArduinoLibrary
+
+_LOGGER = logging.getLogger(__name__)
+
+# The PlatformIO platform the host built under; registry manifests declare
+# compatibility against it, as lib_compat_mode=strict checked before
+PIO_PLATFORM = "native"
+# Namespaces the shared library download cache (pio_components/host/)
+LIBRARY_CACHE_KEY = "host"
+
+# Flag shapes that only the compiler understands; dropped from the link line
+_COMPILE_ONLY_PREFIXES = ("-D", "-U", "-I", "-std=", "-W", *PATH_ARG_FLAGS)
+# Flag shapes that only the linker consumes; inert on a -c compile line
+_LINK_ONLY_PREFIXES = ("-l", "-L", "-Wl,")
+# Link-only flags whose argument is the next token
+_LINK_ONLY_ARG_FLAGS = ("-framework", "-Xlinker", "-z")
+
+
+def parse_flags(entries: Iterable[str], owner: str) -> list[Flag]:
+    """Lex build flag entries into flags, each with its argument.
+
+    Entries are a set, so their order is not the user's: a flag and the
+    argument it takes as the next token must share one entry.
+    """
+    flags: list[Flag] = []
+    for entry in entries:
+        it = iter(lex_build_flags(entry, owner))
+        for tok in it:
+            if tok not in PATH_ARG_FLAGS and tok not in _LINK_ONLY_ARG_FLAGS:
+                flags.append((tok,))
+                continue
+            arg = next(it, None)
+            # A path never starts with "-"; that is the next flag
+            if arg is None or (tok in PATH_ARG_FLAGS and arg.startswith("-")):
+                raise EsphomeError(
+                    f"{owner} build flags have '{tok}' with no argument; write "
+                    f"the flag and its argument as one entry"
+                )
+            flags.append((tok, arg))
+    return flags
+
+
+def split_flags(flags: list[Flag]) -> tuple[list[Flag], list[Flag]]:
+    """Route build flags to the compile and link lines."""
+    compile_flags: list[Flag] = []
+    link_flags: list[Flag] = []
+    for flag in flags:
+        name = flag[0]
+        if len(flag) > 1:
+            (compile_flags if name in PATH_ARG_FLAGS else link_flags).append(flag)
+        elif name.startswith(_LINK_ONLY_PREFIXES):
+            # Checked before the compile prefixes: -Wl, would match -W
+            link_flags.append(flag)
+        elif name.startswith(_COMPILE_ONLY_PREFIXES):
+            compile_flags.append(flag)
+        else:
+            # -g, -O, -f*, -m*, -pthread, --coverage: both lines, as SCons
+            compile_flags.append(flag)
+            link_flags.append(flag)
+    return compile_flags, link_flags
+
+
+def _is_std(flag: Flag) -> bool:
+    return flag[0].startswith("-std=")
+
+
+def _is_cxx_std(flag: Flag) -> bool:
+    return _is_std(flag) and "++" in flag[0]
+
+
+def _anchored_flags(entries: Iterable[str], owner: str) -> list[Flag]:
+    build_path = Path(CORE.build_path)
+    return [
+        anchor_path_flag(flag, build_path)
+        for flag in parse_flags(sorted(entries), owner)
+    ]
+
+
+def _flag_lists() -> tuple[list[str], list[str], list[str]]:
+    """The C, C++, and link flag lists (raw tokens), build_unflags applied.
+
+    ``cg.set_cpp_standard`` wins over any ``-std=`` in the build flags for
+    C++ compiles, as PlatformIO's unflag of every other standard did; C
+    compiles never see a C++ standard.
+    """
+    # The funnel warns and drops empty glued arguments (-D "") itself
+    compile_flags, link_flags = split_flags(
+        _anchored_flags(CORE.build_flags, "esphome")
+    )
+    cflags = [f for f in compile_flags if not _is_cxx_std(f)]
+    cxx_std = CORE.cpp_standard
+    cxxflags = [f for f in compile_flags if not (cxx_std and _is_std(f))]
+    if cxx_std:
+        cxxflags.insert(0, (f"-std={cxx_std}",))
+    cxxflags += [(tok,) for tok in get_project_cxx_compile_flags()]
+
+    # A flag is removed whole, with its argument, as PlatformIO did
+    unflags = set(_anchored_flags(CORE.build_unflags, "esphome build_unflags"))
+    # An unflag that hits nothing (a typo, or -DUSE_FOO against
+    # -DUSE_FOO=1) must be visible, since the user believes the flag is
+    # gone while it still drives the build
+    if unmatched := sorted(unflags - set(cflags) - set(cxxflags) - set(link_flags)):
+        _LOGGER.warning(
+            "build_unflags entries matched no build flag: %s",
+            ", ".join(" ".join(flag) for flag in unmatched),
+        )
+
+    def keep(flags: list[Flag]) -> list[str]:
+        return [tok for flag in flags if flag not in unflags for tok in flag]
+
+    return keep(cflags), keep(cxxflags), keep(link_flags)
+
+
+def _resolve_host_libraries() -> list[ArduinoLibrary]:
+    """Every ``cg.add_library()`` entry, fetched from the registry.
+
+    The host has no framework, so nothing is bundled and no framework
+    compatibility check applies; the platform check keeps the strict
+    manifest gate PlatformIO's native platform enforced. Manifest-less
+    libraries (a bare git checkout) build with PlatformIO's default
+    layout, as they did under its native platform.
+    """
+    if not CORE.platformio_libraries:
+        return []
+    from esphome.arduino.library import resolve_libraries
+
+    return resolve_libraries(
+        None,
+        pio_platform=PIO_PLATFORM,
+        board_mcu="host",
+        cache_key=LIBRARY_CACHE_KEY,
+        framework=None,
+        manifest_optional=True,
+    )
+
+
+def _file_macro_maps(build_dir: Path) -> list[str]:
+    """Flags that keep ``__FILE__`` relative to the build path.
+
+    PlatformIO compiled ``src/x.cpp`` from the build path, and tools name
+    things after that spelling (CodSpeed's benchmark ids). Here a source
+    reaches the compiler by its absolute path, or relative to the build
+    directory when ccache rewrites it.
+    """
+    build_path = Path(CORE.build_path)
+    prefixes = (build_path, Path(os.path.relpath(build_path, build_dir)))
+    return [
+        shell_token(f"-fmacro-prefix-map={prefix}{os.sep}=", force=True)
+        for prefix in prefixes
+    ]
+
+
+def _compiler_version(cxx: tuple[str, ...]) -> str:
+    """What the compiler says it is: its path can stay the same across an
+    update (the macOS shims in /usr/bin)."""
+    result = subprocess.run(
+        [*cxx, "--version"], capture_output=True, text=True, check=False
+    )
+    return result.stdout
+
+
+def write_project(compilers: HostCompilers, ccache: str | None) -> bool:
+    """Write the ninja build for the current configuration.
+
+    ``ccache`` is the caller's already-resolved binary (None when disabled).
+    Returns True when ``build.ninja`` changed, so the caller can skip work
+    derived purely from it (the compile database) on unchanged builds.
+    """
+    build_dir = get_build_dir()
+    mkdir_p(build_dir)
+    src_dir = CORE.relative_src_path()
+    if not src_dir.is_dir():
+        # Generated project state, not install state: clean-all would not help
+        raise EsphomeError(f"Generated source directory {src_dir} is missing")
+
+    cflags, cxxflags, link_flags = _flag_lists()
+    libraries = _resolve_host_libraries()
+
+    include_dirs = [src_dir]
+    for lib in libraries:
+        include_dirs += lib.include_dirs
+    includes = [f"-I{_q(d)}" for d in include_dirs]
+    includes += _file_macro_maps(build_dir)
+
+    # SCons's link line: $LINKFLAGS $SOURCES $_LIBDIRFLAGS $_LIBFLAGS, so
+    # -L and -l trail the objects while every other link token leads
+    lib_dirs = [Path(t[2:]) for t in link_flags if t.startswith("-L")]
+    libs = [t for t in link_flags if t.startswith("-l")]
+    linkflags = [shell_token(t) for t in link_flags if not t.startswith(("-L", "-l"))]
+    for lib in libraries:
+        lib_dirs += lib.link_dirs
+        libs += [f"-l{name}" for name in lib.link_libs]
+        linkflags += [shell_token(f) for f in lib.link_flags]
+
+    # PlatformIO's ASPPCOM passes only -D/-I user flags to assembly
+    asflags = [t for t in cflags if t.startswith(("-D", "-I"))]
+
+    lines = [
+        *tool_lines(compilers.cc, compilers.cxx, ccache),
+        *compile_rule_lines(ccache),
+        *pch_rule_lines(),
+        "rule link",
+        "  command = $cxx -o $out $linkflags @$out.rsp $archives $libdirflags $libflags",
+        "  rspfile = $out.rsp",
+        "  rspfile_content = $in_newline",
+        "  description = LINK $out",
+    ]
+    if any(lib.sources and lib.lib_archive for lib in libraries):
+        # Resolved only when an archive is built, so a system without
+        # binutils still links a library-free configuration
+        lines += ar_rule_lines(find_tool("AR", ("ar",)))
+    lines += [
+        "",
+        f"cflags = {' '.join([*map(shell_token, cflags), *includes])}",
+        f"cxxflags = {' '.join([*map(shell_token, cxxflags), *includes])}",
+        f"asflags = {' '.join([*map(shell_token, asflags), *includes])}",
+        f"linkflags = {' '.join(linkflags)}",
+        f"libdirflags = {' '.join(f'-L{_q(d)}' for d in lib_dirs)}",
+        f"libflags = {' '.join(shell_token(lib) for lib in libs)}",
+        "",
+    ]
+
+    archives, direct_objs = library_edges(lines, libraries)
+
+    src_cxx_override = pch_edges(
+        lines,
+        build_dir,
+        src_dir,
+        PCH_DEFAULT_HEADERS,
+        # The arguments of a CXX override come before the flags
+        [*compilers.cxx[1:], *cxxflags],
+        (),
+        (compilers.cxx[0], _compiler_version(compilers.cxx)) if pch_enabled() else (),
+        compilers.cxx,
+    )
+    src_objs = compile_edges(
+        lines,
+        collect_sources(src_dir),
+        src_dir,
+        "src",
+        cxx_override=src_cxx_override,
+    )
+    if not src_objs:
+        raise EsphomeError(f"No source files found under {src_dir}")
+
+    # Archives are not topologically sorted; GNU ld needs the group to
+    # resolve references between them. ld64 loads archives iteratively and
+    # rejects the option, so macOS lists them bare.
+    archive_tokens = [shell_token(a) for a in archives]
+    if archive_tokens and sys.platform != "darwin":
+        archive_tokens = ["-Wl,--start-group", *archive_tokens, "-Wl,--end-group"]
+    lines.append(
+        f"build {PROGRAM_NAME}: link {' '.join(src_objs + direct_objs)} | "
+        f"{' '.join(_e(a) for a in archives)}"
+    )
+    lines.append(f"  archives = {' '.join(archive_tokens)}")
+    lines.append(f"default {PROGRAM_NAME}")
+    lines.append("")
+
+    return write_file_if_changed(build_dir / "build.ninja", "\n".join(lines))

esphome/build_gen/platformio.py

@@ -1,6 +1,8 @@
+from esphome.build_helpers.pch import pch_script_enabled
 from esphome.const import __version__
 from esphome.core import CORE
 from esphome.helpers import mkdir_p, read_file, write_file_if_changed
+from esphome.platformio.toolchain import copy_pch_script
 from esphome.writer import find_begin_end
 
 INI_AUTO_GENERATE_BEGIN = "; ========== AUTO GENERATED CODE BEGIN ==========="
@@ -62,6 +64,19 @@ def get_ini_content():
 
     # Add extra script for C++ flags
     CORE.add_platformio_option("extra_scripts", [f"pre:{CXX_FLAGS_FILE_NAME}"])
+    if pch_script_enabled():
+        CORE.add_platformio_option("extra_scripts", ["post:pch.py"])
+
+    # Add CMake args. A user-supplied value (str or list) is deliberately
+    # replaced; this option was always overwritten at FINAL priority.
+    if CORE.cmake_args:
+        CORE.add_platformio_option(
+            "board_build.cmake_extra_args",
+            " ".join(
+                f"-D{name}={value}" for name, value in sorted(CORE.cmake_args.items())
+            ),
+            replace=True,
+        )
 
     content = "[platformio]\n"
     content += f"description = ESPHome {__version__}\n"
@@ -95,6 +110,8 @@ def write_project():
 
     # Write extra script for C++ specific flags
     write_cxx_flags_script()
+    if pch_script_enabled():
+        copy_pch_script()
 
 
 CXX_FLAGS_FILE_NAME = "cxx_flags.py"

esphome/build_helpers/__init__.py

@@ -0,0 +1 @@
+"""Build helpers shared by the native (non-PlatformIO) toolchains."""

esphome/build_helpers/ccache.py

@@ -0,0 +1,131 @@
+"""Shared ccache policy for build backends: env-knob parsing, binary
+resolution, and default ``CCACHE_*`` values."""
+
+from __future__ import annotations
+
+import logging
+import os
+from pathlib import Path
+
+from esphome.framework_helpers import strip_win_long_path_prefix, tool_version_runs
+from esphome.helpers import FALSY_ENV_STRINGS, TRUTHY_ENV_STRINGS
+
+_LOGGER = logging.getLogger(__name__)
+
+
+def _ccache_runs(ccache: str) -> bool:
+    """Return True when the ``ccache`` found on PATH actually runs."""
+    return tool_version_runs(
+        ccache,
+        "Ignoring ccache at %s because it failed to run; compiling without ccache",
+    )
+
+
+def parse_enable_env(name: str) -> bool | None:
+    """Strictly parse an on/off environment knob; None when unset or invalid.
+
+    ``bool(str)`` truthiness would flip ``no``/``off`` to enabled, so only
+    1/true/yes/on and 0/false/no/off count; anything else warns and reads
+    as unset so the caller's default policy applies.
+    """
+    raw = os.environ.get(name)
+    if raw is None:
+        return None
+    lowered = raw.strip().lower()
+    if not lowered:
+        # ENV KNOB= (Docker/CI) has always read as a disable
+        return False
+    if lowered in TRUTHY_ENV_STRINGS:
+        return True
+    if lowered in FALSY_ENV_STRINGS:
+        return False
+    _LOGGER.warning("Ignoring unrecognized %s=%r; use 1 or 0", name, raw)
+    return None
+
+
+def resolve_ccache_path() -> str | None:
+    """The ccache binary to wrap compiles with, or None when disabled.
+
+    An explicit ``ESPHOME_CCACHE_ENABLE=1`` skips the runnability probe; the
+    Windows extended-length prefix is stripped before probing (#18399).
+    """
+    import shutil
+
+    explicit = parse_enable_env("ESPHOME_CCACHE_ENABLE")
+    if explicit is False:
+        return None
+    ccache = shutil.which("ccache")
+    if ccache is None:
+        if explicit:
+            _LOGGER.warning(
+                "ESPHOME_CCACHE_ENABLE is set but no ccache binary is on PATH; "
+                "compiling without ccache"
+            )
+        return None
+    ccache = strip_win_long_path_prefix(ccache)
+    if not explicit and not _ccache_runs(ccache):
+        return None
+    return ccache
+
+
+def resolve_absolute_ccache_path() -> str | None:
+    """``resolve_ccache_path`` for the ninja backends, which run their
+    commands from the build directory, where a relative path is lost."""
+    from esphome.build_helpers.ninja import absolute_tool
+
+    ccache = resolve_ccache_path()
+    return absolute_tool(ccache) if ccache else None
+
+
+def ccache_defaults_env(cache_dir: Path) -> dict[str, str]:
+    """Default ``CCACHE_*`` values for a build subprocess (not os.environ).
+
+    Values the user already set in the environment are respected. Depend
+    mode is on: both native backends emit depfiles (-MMD / CMake), which
+    keeps cache-miss overhead low.
+    """
+    from esphome.core import CORE
+
+    # An unset build_path means the env was built before preload; fail loudly
+    # rather than silently drop CCACHE_BASEDIR.
+    if CORE.build_path is None:
+        raise ValueError(
+            "CORE.build_path must be set before constructing the build environment"
+        )
+    defaults = {
+        # ccache expands $VAR in its settings; $$ is a literal $
+        "CCACHE_DIR": str(cache_dir).replace("$", "$$"),
+        "CCACHE_NOHASHDIR": "true",
+        "CCACHE_DEPEND": "1",
+        "CCACHE_BASEDIR": str(Path(CORE.build_path).resolve()).replace("$", "$$"),
+    }
+    return {k: v for k, v in defaults.items() if k not in os.environ}
+
+
+def effective_ccache_basedir() -> str:
+    """The prefix ccache strips from hashed paths: a usable user
+    CCACHE_BASEDIR, else the resolved build path."""
+    from esphome.core import CORE
+
+    raw = os.environ.get("CCACHE_BASEDIR")
+    if raw is not None and Path(raw).is_absolute() and len(Path(raw).parts) > 1:
+        return raw
+    return str(Path(CORE.build_path).resolve())
+
+
+def ccache_env(ccache: str | None, tools_cache: tuple[str, str]) -> dict[str, str]:
+    """The ccache settings for a build subprocess (not os.environ).
+
+    ``ccache`` is the pre-resolved binary (resolve_ccache_path), or None when
+    disabled; ``tools_cache`` is the backend's tools cache spec, which holds
+    its ccache dir. The pch settings include ``time_macros``: a cached
+    object can keep an older ``__DATE__`` or ``__TIME__``.
+    """
+    if ccache is None:
+        return {}
+    from esphome.build_helpers.pch import ccache_pch_env
+    from esphome.build_helpers.tools_cache import tools_cache_path
+
+    env = ccache_defaults_env(tools_cache_path(*tools_cache) / "ccache")
+    env.update(ccache_pch_env())
+    return env

esphome/build_helpers/idedata.py

@@ -0,0 +1,406 @@
+"""Derive idedata from a native (non-PlatformIO) build's ``compile_commands.json``.
+
+PlatformIO exposes a curated ``pio run -t idedata`` JSON; the native
+toolchains have no such command, but each build produces a
+``compile_commands.json`` (CMAKE_EXPORT_COMPILE_COMMANDS for ESP-IDF, ninja's
+compdb tool otherwise). This module turns that file into the same fields
+consumers (IDE integration, clang-tidy) expect:
+
+    {cc_path, cxx_path, cxx_flags, defines, includes: {build, toolchain}}
+"""
+
+from __future__ import annotations
+
+from collections.abc import Callable
+import json
+import logging
+import os
+from pathlib import Path
+import shlex
+import subprocess
+
+from esphome.core import EsphomeError
+from esphome.helpers import write_file
+
+_LOGGER = logging.getLogger(__name__)
+
+# Everything idedata generation may raise after a successful link; idedata
+# is a bonus artifact, so consumers warn instead of failing the build
+IDEDATA_BEST_EFFORT_ERRORS = (
+    EsphomeError,
+    LookupError,
+    OSError,
+    RuntimeError,
+    ValueError,
+)
+
+
+def warn_if_idedata_missing(get_idedata: Callable[[], dict | None]) -> None:
+    """Run an idedata generator, downgrading any failure to a warning:
+    the firmware already built."""
+    try:
+        if get_idedata() is None:
+            _LOGGER.warning("No idedata was generated for this build")
+    except IDEDATA_BEST_EFFORT_ERRORS as err:
+        _LOGGER.warning(
+            "Could not generate idedata: %s (IDE, clang-tidy, and "
+            "memory-analysis data will be unavailable for this build)",
+            err,
+        )
+        _LOGGER.debug("Idedata failure detail", exc_info=True)
+
+
+# C++ translation-unit suffixes used to identify ESPHome source files.
+_CXX_SUFFIXES = (".cpp", ".cc")
+# Suffixes of input/output files that appear bare on the command line (and so
+# must not be mistaken for compiler flags).
+_INPUT_FILE_SUFFIXES = (*_CXX_SUFFIXES, ".c", ".o", ".S", ".s")
+# Path marker identifying an ESPHome source translation unit.
+_ESPHOME_SRC_MARKER = "/src/esphome/"
+
+
+def _is_esphome_src(file: str) -> bool:
+    """Whether ``file`` is an ESPHome C++ translation unit; normalized to
+    ``/`` first since Windows compile DBs use backslashes."""
+    return _ESPHOME_SRC_MARKER in file.replace("\\", "/") and file.endswith(
+        _CXX_SUFFIXES
+    )
+
+
+def _split_command(command: str) -> list[str]:
+    r"""Tokenize a compile_commands.json / response-file command string.
+
+    On Windows, tokenize per Windows ``argv`` rules via ``CommandLineToArgvW``.
+    ESP-IDF's compile_commands.json there mixes two backslash conventions in one
+    string: literal path separators in the compiler path (``C:\Users\...g++.exe``,
+    no quote follows) and shell quote-escaping in -D defines (``-DVER=\"1.2.3\"``).
+    Only the real Windows parser — where a backslash escapes solely a following
+    quote — handles both, and it is the exact tokenizer the compiler is launched
+    with. ``shlex`` cannot: POSIX mode eats the path separators, and disabling
+    its escape mangles the defines.
+    """
+    if os.name != "nt":
+        return shlex.split(command)
+
+    import ctypes
+    from ctypes import wintypes
+
+    # CommandLineToArgvW("") returns the current process name, not []; guard it
+    # so an empty response file tokenizes the same as it would via shlex.
+    if not command.strip():
+        return []
+
+    CommandLineToArgvW = ctypes.windll.shell32.CommandLineToArgvW
+    CommandLineToArgvW.argtypes = [wintypes.LPCWSTR, ctypes.POINTER(ctypes.c_int)]
+    CommandLineToArgvW.restype = ctypes.POINTER(wintypes.LPWSTR)
+    argc = ctypes.c_int()
+    argv = CommandLineToArgvW(command, ctypes.byref(argc))
+    if not argv:  # pragma: no cover
+        raise ctypes.WinError()
+    try:
+        return [argv[i] for i in range(argc.value)]
+    finally:
+        ctypes.windll.kernel32.LocalFree(argv)
+
+
+def _expand_response_files(tokens: list[str], directory: Path) -> list[str]:
+    """Inline any ``@response-file`` arguments (paths relative to ``directory``).
+
+    GCC response files embed flags that must be expanded so GCC-only flags
+    inside them (e.g. ``-mlongcalls``) can be filtered downstream; left as
+    ``@file`` clang would read them and choke.
+    """
+    out: list[str] = []
+    for tok in tokens:
+        if tok.startswith("@"):
+            rf = Path(tok[1:])
+            if not rf.is_absolute():
+                rf = directory / rf
+            try:
+                out.extend(
+                    _expand_response_files(
+                        _split_command(rf.read_text(encoding="utf-8")), directory
+                    )
+                )
+                continue
+            except OSError as err:
+                # Keep the literal token if the file can't be read, but log it
+                # so the (otherwise opaque) downstream clang failure is traceable.
+                _LOGGER.warning("Could not read response file %s: %s", rf, err)
+        out.append(tok)
+    return out
+
+
+def _pick_entry(entries: list[dict]) -> dict:
+    """Pick a representative ESPHome C++ TU; all share the same component
+    flags/defines."""
+    for entry in entries:
+        if _is_esphome_src(entry["file"]):
+            return entry
+    for entry in entries:
+        if entry["file"].endswith(_CXX_SUFFIXES):
+            return entry
+    raise ValueError("no C++ translation unit found in compile_commands.json")
+
+
+# Compiler launchers that may prefix a compile command; a closed launcher
+# denylist beats enumerating compiler names, an open set.
+_LAUNCHER_STEMS = frozenset({"ccache", "sccache", "distcc", "icecc", "buildcache"})
+
+
+def _is_launcher(token: str) -> bool:
+    return Path(token).stem.lower() in _LAUNCHER_STEMS
+
+
+def is_joined_include(tok: str) -> bool:
+    """The joined ``-includefoo.h`` spelling; excludes clang's -include-pch."""
+    return (
+        tok.startswith("-include")
+        and tok != "-include"
+        and not tok.startswith("-include-")
+    )
+
+
+def parse_entry(
+    entry: dict, launcher: str | None = None
+) -> tuple[str, list[str], list[str], list[str]]:
+    """Parse one compile_commands entry -> (cxx_path, defines, includes, cxx_flags)."""
+    directory = Path(entry["directory"])
+    tokens = _expand_response_files(_split_command(entry["command"]), directory)
+
+    def _include(raw: str) -> str:
+        # Resolve against the entry's ``directory`` so cached idedata works
+        # from any cwd; emit forward slashes to match the JSON's own entries
+        raw = raw.strip()
+        if raw and not Path(raw).is_absolute():
+            raw = os.path.normpath(directory / raw)
+        return raw.replace("\\", "/")
+
+    # A launcher-wrapped command ("ccache g++ ...") names the compiler second
+    if launcher is not None and tokens[:1] == [launcher]:
+        tokens = tokens[1:]
+    if not tokens:
+        # An empty command, or one that was only the launcher; fail by name
+        raise ValueError(f"empty compile command for {entry.get('file')}")
+    if _is_launcher(tokens[0]) and len(tokens) > 1 and not tokens[1].startswith("-"):
+        # Stale DB built with a launcher this run no longer configures; the
+        # real compiler is the next token
+        _LOGGER.warning("Stripping unconfigured launcher %s", tokens[0])
+        tokens = tokens[1:]
+    # token0 is the compiler path; the rest of the command already uses forward
+    # slashes on Windows, so normalize it too for a consistent idedata file.
+    cxx_path = tokens[0].replace("\\", "/")
+    # Enforced here so no caller can record ccache as the compiler
+    reject_launcher_compiler(cxx_path)
+    defines: list[str] = []
+    includes: list[str] = []
+    cxx_flags: list[str] = []
+
+    it = iter(tokens[1:])
+    for tok in it:
+        if tok in ("-c", "-o"):
+            next(it, None)  # drop the flag and its argument (input/output)
+        elif tok.startswith("-D"):
+            # ``.strip()`` handles tokens like ``-D CONFIGURED=1`` (a single
+            # quoted arg with a space after -D) that some flags arrive as.
+            defines.append(tok[2:].strip() if len(tok) > 2 else next(it, "").strip())
+        elif tok.startswith("-I"):
+            includes.append(_include(tok[2:] if len(tok) > 2 else next(it, "")))
+        elif tok == "-isystem":
+            includes.append(_include(next(it, "")))
+        elif tok.startswith("-isystem"):
+            includes.append(_include(tok[len("-isystem") :]))
+        elif tok in ("-MT", "-MF", "-MQ"):
+            next(it, None)  # dependency-file flag + its argument
+        elif tok.startswith(("-MD", "-MMD", "-MP", "-MM")):
+            pass  # dependency-generation flags, no argument
+        elif tok.endswith(_INPUT_FILE_SUFFIXES):
+            pass  # input/output files
+        else:
+            cxx_flags.append(tok)
+    return cxx_path, defines, includes, cxx_flags
+
+
+def get_toolchain_includes(cxx_path: str) -> list[str]:
+    """Query the compiler for its builtin ``#include <...>`` search dirs."""
+    result = subprocess.run(
+        [cxx_path, "-E", "-x", "c++", "-", "-v"],
+        input="",
+        text=True,
+        stdout=subprocess.DEVNULL,
+        stderr=subprocess.PIPE,
+        check=False,
+        close_fds=False,
+    )
+    includes: list[str] = []
+    capture = False
+    for line in result.stderr.splitlines():
+        if "#include <...> search starts here:" in line:
+            capture = True
+            continue
+        if "End of search list." in line:
+            break
+        if capture:
+            includes.append(line.strip())
+    if result.returncode != 0 or not includes:
+        raise RuntimeError(
+            f"Could not query builtin include dirs from {cxx_path} "
+            f"(return code {result.returncode}); stderr:\n{result.stderr.strip()}"
+        )
+    return includes
+
+
+def _cc_path_from_cxx(cxx_path: str) -> str:
+    """Derive the C compiler path from the C++ compiler path.
+
+    compile_commands.json only names the C++ compiler, but consumers reach the
+    rest of the toolchain (objdump, readelf, addr2line) by rewriting the tail of
+    ``cc_path``, so they need the ``gcc``-suffixed name.
+    """
+    stem, suffix = (
+        (cxx_path[: -len(".exe")], ".exe")
+        if cxx_path.endswith(".exe")
+        else (cxx_path, "")
+    )
+    # Rewrite the program name only when it is g++ itself, or a toolchain
+    # prefixed one such as xtensa-esp32-elf-g++ -> xtensa-esp32-elf-gcc.
+    # Requiring a separator before the "g++" keeps names that merely end in
+    # those three characters intact: "clang++" must not become "clangcc".
+    head = stem[: -len("g++")]
+    if stem.endswith("g++") and (not head or head.endswith(("-", "/", "\\"))):
+        stem = f"{head}gcc"
+    return f"{stem}{suffix}"
+
+
+def _cache_usable(cached: object) -> bool:
+    """Check a cached idedata dict against the guarantees of the write path.
+
+    Caches written by older versions predate the launcher rejection and the
+    include-union shape; serving one would bypass both. The dict check also
+    keeps "in" from substring-matching a bare JSON string.
+    """
+    if not isinstance(cached, dict) or "cc_path" not in cached:
+        return False
+    cxx_path = cached.get("cxx_path")
+    if not isinstance(cxx_path, str) or _is_launcher(cxx_path):
+        return False
+    includes = cached.get("includes")
+    return isinstance(includes, dict) and isinstance(includes.get("build"), list)
+
+
+def load_or_build_idedata(
+    compile_commands: Path,
+    elf_path: Path,
+    cache: Path,
+    launcher: str | None = None,
+) -> dict | None:
+    """Return idedata for a compile_commands.json build, cached on mtime.
+
+    Shared by the native ESP-IDF and ESP8266 Arduino toolchains. Returns None
+    when the compile DB doesn't exist yet (nothing was built). ``launcher``
+    is the compiler-launcher path (ccache) the build was generated with, if
+    any; commands in the compile DB are prefixed with it.
+    """
+    if not compile_commands.is_file():
+        _LOGGER.debug("No %s yet; skipping idedata generation", compile_commands)
+        return None
+
+    if cache.is_file() and cache.stat().st_mtime >= compile_commands.stat().st_mtime:
+        try:
+            cached = json.loads(cache.read_text(encoding="utf-8"))
+        except (ValueError, OSError) as err:
+            # A recurring cause (interrupted write, disk full) would otherwise
+            # look like unexplained slow builds
+            _LOGGER.warning("Discarding unreadable idedata cache %s: %s", cache, err)
+        else:
+            if _cache_usable(cached):
+                # Re-stamp so a relocated build dir cannot serve a stale ELF path
+                cached["prog_path"] = str(elf_path)
+                return cached
+            _LOGGER.debug("Regenerating idedata: cache %s fails validation", cache)
+
+    data = idedata_from_build(compile_commands, launcher)
+    data["prog_path"] = str(elf_path)
+    cache.parent.mkdir(parents=True, exist_ok=True)
+    # Atomic so a crash mid-write cannot leave a truncated cache
+    write_file(cache, json.dumps(data, indent=2) + "\n")
+    return data
+
+
+def reject_launcher_compiler(cxx_path: str) -> None:
+    """Reject a compile DB naming a launcher (ccache) as the compiler; it
+    must never be probed, cached, or consumed."""
+    if _is_launcher(cxx_path):
+        raise EsphomeError(
+            f"compile_commands.json names the launcher {cxx_path} as the "
+            "compiler; the compile database is unusable"
+        )
+
+
+def idedata_from_build(compile_commands: Path, launcher: str | None = None) -> dict:
+    """Parse compile_commands.json into the idedata fields consumers expect.
+
+    A single compile entry only carries the include set its own translation
+    unit was built with (per-component under ESP-IDF), but consumers
+    (clang-tidy) analyze ESPHome headers that transitively pull in other
+    components. So take cxx_path / cxx_flags / defines from a representative
+    ESPHome TU, but union the include dirs across all ESPHome TUs to get a
+    project-wide superset (as PlatformIO's idedata provides).
+    """
+    entries = json.loads(Path(compile_commands).read_text(encoding="utf-8"))
+    if not isinstance(entries, list) or not all(isinstance(e, dict) for e in entries):
+        # A TypeError here would escape IDEDATA_BEST_EFFORT_ERRORS
+        raise EsphomeError(f"{compile_commands} is not a compile-command list")
+
+    representative = _pick_entry(entries)
+    cxx_path, defines, rep_includes, cxx_flags = parse_entry(representative, launcher)
+
+    # Seed with the representative's includes so it is not parsed twice
+    has_esphome_tu = _is_esphome_src(representative["file"])
+    build_includes: dict[str, None] = dict.fromkeys(
+        rep_includes if has_esphome_tu else ()
+    )
+
+    def _shape(entry: dict) -> str:
+        # directory + command minus TU-specific paths: same shape means the
+        # same include set, so tokenize once per shape. Response-file
+        # commands never dedupe (the .rsp contents differ per object)
+        command = entry["command"]
+        directory = entry.get("directory", "")
+        if "@" in command:
+            return f"unique:{directory}|{entry.get('output') or command}"
+        stripped = command.replace(entry.get("file", ""), "").replace(
+            entry.get("output", ""), ""
+        )
+        return f"{directory}|{stripped}"
+
+    seen_shapes = {_shape(representative)}
+    for entry in entries:
+        if entry is representative or not _is_esphome_src(entry["file"]):
+            continue
+        has_esphome_tu = True
+        if (shape := _shape(entry)) in seen_shapes:
+            _LOGGER.debug("Include union: %s shares a command shape", entry["file"])
+            continue
+        seen_shapes.add(shape)
+        for inc in parse_entry(entry, launcher)[2]:
+            build_includes.setdefault(inc, None)
+
+    if not has_esphome_tu:
+        # An arbitrary fallback TU breaks clang-tidy/IDE consumers, and a
+        # warning would be cached into permanence; call sites downgrade this
+        raise EsphomeError(
+            f"No ESPHome translation unit found in {compile_commands}; "
+            "refusing to cache unusable idedata"
+        )
+
+    return {
+        "cc_path": _cc_path_from_cxx(cxx_path),
+        "cxx_path": cxx_path,
+        "cxx_flags": cxx_flags,
+        "defines": defines,
+        "includes": {
+            "build": list(build_includes),
+            "toolchain": get_toolchain_includes(cxx_path),
+        },
+    }

esphome/build_helpers/native.py

@@ -0,0 +1,74 @@
+"""Resolution of the native (non-PlatformIO) build backend for a config.
+
+Kept deliberately light: the serial upload and logs fast path resolves a
+backend for its artifact paths alone, so importing this must not pull in a
+platform component package or the backend itself.
+"""
+
+from __future__ import annotations
+
+from collections.abc import Collection
+import importlib
+import logging
+from types import ModuleType
+
+from esphome.const import Toolchain
+from esphome.core import CORE, EsphomeError
+
+_LOGGER = logging.getLogger(__name__)
+
+# Native build backend per (target platform, toolchain)
+NATIVE_TOOLCHAIN_MODULES = {
+    ("esp32", Toolchain.ESP_IDF): "esphome.espidf.toolchain",
+    ("esp8266", Toolchain.ARDUINO): "esphome.arduino8266.toolchain",
+    ("host", Toolchain.HOST): "esphome.host.toolchain",
+}
+
+
+def native_backend() -> ModuleType | None:
+    """The native build backend module for the resolved toolchain."""
+    if not CORE.using_native_toolchain:
+        return None
+    key = (CORE.target_platform, CORE.toolchain)
+    if (module_path := NATIVE_TOOLCHAIN_MODULES.get(key)) is None:
+        # Degrading to the PlatformIO path would build with the wrong backend
+        raise EsphomeError(
+            f"Toolchain '{CORE.toolchain.value}' has no native build backend "
+            f"module for platform {CORE.target_platform}"
+        )
+    return importlib.import_module(module_path)
+
+
+# Binutils and the linked image for memory analysis, for toolchains that build
+# without PlatformIO but have no native build backend (which supplies them)
+ANALYSIS_TOOLCHAIN_MODULES = {
+    ("nrf52", Toolchain.SDK_NRF): "esphome.components.nrf52.toolchain",
+}
+
+
+def analysis_backend() -> ModuleType | None:
+    """The module giving objdump, readelf and the ELF of a non-PlatformIO build.
+
+    None means PlatformIO's idedata supplies them (or nothing can).
+    """
+    if (native := native_backend()) is not None:
+        return native
+    module_path = ANALYSIS_TOOLCHAIN_MODULES.get((CORE.target_platform, CORE.toolchain))
+    return importlib.import_module(module_path) if module_path else None
+
+
+def warn_ignored_platformio_options(consumed: Collection[str]) -> None:
+    """Warn for component-added platformio options a native build drops.
+
+    User-supplied keys were already routed or warned about by
+    ``core/config.py``; what survives into ``CORE.platformio_options`` came
+    from ``cg.add_platformio_option`` calls in components.
+    """
+    for key in sorted(CORE.platformio_options or {}):
+        if key not in consumed:
+            _LOGGER.warning(
+                "platformio_options->%s is ignored when building with the "
+                "native '%s' toolchain",
+                key,
+                CORE.toolchain.value,
+            )

esphome/build_helpers/ninja.py

@@ -0,0 +1,182 @@
+"""Platform-neutral helpers for ninja-driven native builds."""
+
+from __future__ import annotations
+
+import json
+import logging
+import os
+from pathlib import Path
+import re
+import shutil
+import subprocess
+
+from esphome.core import EsphomeError
+from esphome.framework_helpers import strip_win_long_path_prefix, tool_version_runs
+from esphome.helpers import write_file_if_changed
+
+_LOGGER = logging.getLogger(__name__)
+
+
+def _ninja_runs(binary: str) -> bool:
+    """Whether the ninja found on PATH actually runs (see tool_version_runs)."""
+    return tool_version_runs(
+        binary,
+        "Ignoring ninja at %s because it failed to run; "
+        "falling back to the bundled wheel",
+    )
+
+
+# Compile rule names the generators emit; ninja's compdb tool is asked for
+# exactly these, so a renamed rule fails the build instead of stranding idedata
+COMPILE_RULES = ("c", "cxx", "aspp", "asm")
+
+
+def absolute_tool(tool: str | Path) -> str:
+    """A tool path that still resolves from the build directory.
+
+    ``shutil.which`` returns a relative path for a relative PATH entry, and
+    ninja runs the commands from ``.pioenvs/<name>``. Symlinks are kept:
+    ccache's compiler links depend on the name they are called by.
+    """
+    return strip_win_long_path_prefix(str(Path(tool).absolute()))
+
+
+def find_ninja() -> Path:
+    """Locate the ninja binary: a runnable PATH hit first, else the ninja
+    PyPI wheel."""
+    if binary := shutil.which("ninja"):
+        binary = absolute_tool(binary)
+        if _ninja_runs(binary):
+            return Path(binary)
+    import_error: ImportError | None = None
+    try:
+        import ninja
+    except ImportError as err:
+        import_error = err
+        wheel_binary = None
+    else:
+        wheel_binary = Path(ninja.BIN_DIR) / (
+            "ninja.exe" if os.name == "nt" else "ninja"
+        )
+    if wheel_binary is None or not wheel_binary.is_file():
+        raise EsphomeError(
+            "ninja not found on PATH or in the ninja package; reinstall the "
+            "esphome Python environment"
+        ) from import_error
+    return wheel_binary
+
+
+def escape(value: Path | str) -> str:
+    """Escape a path or token for a ninja file.
+
+    ninja has no escape for ``|`` or a line break in a path, so those fail
+    here by name instead of producing a build file ninja misreads.
+    """
+    text = str(value)
+    if bad := next((c for c in "|\r\n" if c in text), None):
+        raise EsphomeError(
+            f"Path {text!r} contains {bad!r}, which a ninja build file cannot "
+            "express; rename the file or directory"
+        )
+    return text.replace("$", "$$").replace(":", "$:").replace(" ", "$ ")
+
+
+def quote_arg(tok: str) -> str:
+    """Quote with the CreateProcess argv rule (as ``subprocess.list2cmdline``):
+    backslash runs double only before a quote. Windows-only; ``$`` must
+    already be doubled for ninja.
+    """
+    quoted = re.sub(r'(\\*)"', lambda m: m.group(1) * 2 + '\\"', tok)
+    quoted = re.sub(r"(\\+)\Z", lambda m: m.group(1) * 2, quoted)
+    return f'"{quoted}"'
+
+
+# Force-quote any token containing a character outside the shlex.quote-style
+# safe set: ninja hands POSIX commands to /bin/sh -c, so bare (, ;, <, *, `
+# and friends would be re-parsed as shell syntax.
+_NEEDS_QUOTE = re.compile(r"[^\w@%+=:,./-]")
+
+
+def shell_token(tok: str, force: bool = False) -> str:
+    """Re-quote a lexed token for the platform shell; ``force`` always quotes.
+
+    Single quotes on POSIX (/bin/sh), the argv rule on Windows
+    (CreateProcess). ``$`` is doubled first because ninja expands it before
+    the command reaches the shell.
+    """
+    tok = tok.replace("$", "$$")  # ninja would expand a bare $ to nothing
+    if not (force or not tok or _NEEDS_QUOTE.search(tok)):
+        return tok
+    # An empty token must become '' / "" or it vanishes from the argv
+    if os.name == "nt":
+        return quote_arg(tok)
+    # shlex.quote's rule; inlined because the $-doubled token must not be
+    # re-examined for safe characters
+    return "'" + tok.replace("'", "'\"'\"'") + "'"
+
+
+def quote_path(value: Path | str) -> str:
+    """Force-quote a path for the ninja command line (shell/CreateProcess)."""
+    return shell_token(str(value), force=True)
+
+
+def refresh_compile_commands(
+    ninja_path: Path, build_dir: Path, env: dict[str, str], ninja_changed: bool
+) -> None:
+    """Regenerate the compile DB (a pure function of build.ninja) when stale.
+
+    Freshness rides a stamp: the DB itself is written through
+    write_file_if_changed (its mtime feeds the idedata cache), so a
+    regeneration with identical content would stay "stale" forever. An
+    interrupted previous run may have rewritten the manifest without
+    regenerating the DB, hence the mtime comparison.
+    """
+    compdb = build_dir / "compile_commands.json"
+    compdb_stamp = build_dir / ".compile_commands.stamp"
+    ninja_file = build_dir / "build.ninja"
+    if (
+        ninja_changed
+        or not compdb.is_file()
+        or not compdb_stamp.is_file()
+        or compdb_stamp.stat().st_mtime < ninja_file.stat().st_mtime
+    ):
+        write_compile_commands(ninja_path, build_dir, env)
+        compdb_stamp.touch()
+
+
+def write_compile_commands(
+    ninja_path: Path, build_dir: Path, env: dict[str, str]
+) -> None:
+    compdb = build_dir / "compile_commands.json"
+    result = subprocess.run(
+        [str(ninja_path), "-C", str(build_dir), "-t", "compdb", *COMPILE_RULES],
+        env=env,
+        capture_output=True,
+        text=True,
+        check=False,
+        close_fds=False,
+    )
+    if result.returncode != 0:
+        # Drop any stale database so consumers (IDE integration, clang-tidy,
+        # the memory analyzer) can't silently read outdated data
+        compdb.unlink(missing_ok=True)
+        raise EsphomeError(f"Could not generate compile_commands.json: {result.stderr}")
+    try:
+        entries = json.loads(result.stdout)
+    except ValueError as err:
+        compdb.unlink(missing_ok=True)
+        raise EsphomeError(
+            f"ninja produced an unparsable compile database: {err} "
+            f"(output starts {result.stdout[:120]!r})"
+        ) from err
+    if not entries:
+        # compdb exits 0 with [] for unknown rule names; a renamed compile
+        # rule must fail the build, not silently strand every consumer
+        compdb.unlink(missing_ok=True)
+        raise EsphomeError(
+            "ninja produced an empty compile database; the generator's rule "
+            "names no longer match"
+        )
+    # write_file_if_changed keeps the mtime stable on no-op builds so the
+    # idedata cache stays valid
+    write_file_if_changed(compdb, result.stdout)

esphome/build_helpers/ninja_gen.py

@@ -0,0 +1,288 @@
+"""The parts of a ``build.ninja`` every native backend emits the same way.
+
+Rule names match ``SOURCE_KIND_FOR_SUFFIX`` values (c, cxx, asm, aspp) and
+``ninja.COMPILE_RULES``, which the compile database is asked for.
+"""
+
+from __future__ import annotations
+
+from collections.abc import Collection, Sequence
+import logging
+import os
+from pathlib import Path
+import sys
+from typing import TYPE_CHECKING
+
+from esphome.build_helpers.idedata import is_joined_include
+from esphome.build_helpers.ninja import (
+    escape as _e,
+    quote_path as _q,
+    shell_token as _shell_token,
+)
+from esphome.build_helpers.pch import (
+    PCH_GCH_NAME,
+    PCH_SUM_NAME,
+    log_pch_in_use,
+    pch_consumer_flags,
+    pch_identity,
+    pch_usable,
+    write_pch_headers,
+)
+from esphome.framework_helpers import strip_win_long_path_prefix
+from esphome.helpers import write_file_if_changed
+from esphome.platformio.library import SOURCE_KIND_FOR_SUFFIX
+
+if TYPE_CHECKING:
+    from esphome.arduino.library import ArduinoLibrary
+
+_LOGGER = logging.getLogger(__name__)
+
+_BUILD_TOOL = Path(__file__).parent.parent / "build_gen" / "build_tool.py"
+
+
+def collect_sources(root: Path, exclude: Collection[str] = frozenset()) -> list[Path]:
+    return sorted(
+        p
+        for p in root.rglob("*")
+        if p.suffix in SOURCE_KIND_FOR_SUFFIX and p.name not in exclude
+    )
+
+
+def common_parent(paths: list[Path]) -> Path:
+    return Path(os.path.commonpath([str(p.parent) for p in paths]))
+
+
+def _command(words: Sequence[Path | str]) -> str:
+    program, *args = words
+    return " ".join([_q(program), *(_shell_token(str(a)) for a in args)])
+
+
+def tool_lines(
+    cc: Sequence[Path | str], cxx: Sequence[Path | str], ccache: str | None
+) -> list[str]:
+    """The file header: the compilers and the helper tools as variables.
+
+    A compiler is its program followed by any arguments it always takes.
+    """
+    return [
+        "# Auto-generated by ESPHome",
+        "ninja_required_version = 1.5",
+        f"cc = {_command(cc)}",
+        f"cxx = {_command(cxx)}",
+        # The NSIS launcher starts Python with a \\?\ extended-length path
+        # that cmd.exe cannot spawn; same strip every other emitted binary
+        # path gets
+        f"python = {_q(strip_win_long_path_prefix(sys.executable))}",
+        f"buildtool = {_q(_BUILD_TOOL)}",
+        *([f"ccache = {_q(ccache)}"] if ccache else []),
+        "",
+    ]
+
+
+def compile_rule_lines(ccache: str | None) -> list[str]:
+    """The compile rules; ``$own_includes`` is empty unless an edge sets it.
+
+    ``ccache`` is the launcher ``tool_lines`` was given; the same test here
+    keeps the variable and the rules in step. It is spliced in rather than
+    left as an empty variable: a leading space on the command line makes
+    CreateProcess fail on Windows.
+    """
+    launcher = "$ccache " if ccache else ""
+    return [
+        "rule c",
+        f"  command = {launcher}$cc -MMD -MF $out.d $own_includes $cflags $flags -c $in -o $out",
+        "  depfile = $out.d",
+        "  deps = gcc",
+        "  description = CC $out",
+        "rule cxx",
+        f"  command = {launcher}$cxx -MMD -MF $out.d $own_includes $cxxflags $flags -c $in -o $out",
+        "  depfile = $out.d",
+        "  deps = gcc",
+        "  description = CXX $out",
+        "rule aspp",
+        f"  command = {launcher}$cc -MMD -MF $out.d -x assembler-with-cpp $own_includes $asflags $flags -c $in -o $out",
+        "  depfile = $out.d",
+        "  deps = gcc",
+        "  description = AS $out",
+        # Plain assembler, as SCons's ASCOM: no preprocessor, so no
+        # depfile and no $flags (defines/includes) either
+        "rule asm",
+        f"  command = {launcher}$cc -x assembler $asflags -c $in -o $out",
+        "  description = AS $out",
+    ]
+
+
+def pch_rule_lines() -> list[str]:
+    """The precompiled header rule, for a generator that emits one."""
+    return [
+        # No $ccache: the .gch embeds build dir paths
+        "rule pch",
+        "  command = $cxx -MMD -MF $out.d -x c++-header $cxxflags $flags -c $in -o $out",
+        "  depfile = $out.d",
+        "  deps = gcc",
+        "  description = PCH $out",
+    ]
+
+
+def pch_edges(
+    lines: list[str],
+    build_dir: Path,
+    src_dir: Path,
+    headers: Sequence[str],
+    cxxflags: Sequence[str],
+    src_flags: Sequence[str],
+    identity: Sequence[str],
+    cxx: Sequence[Path | str],
+) -> tuple[str, str] | None:
+    """Emit the precompiled header for the C++ src edges.
+
+    ``headers`` are folded into one prefix header, ``src_flags`` are the
+    flags every src edge carries, ``identity`` names what else the compile
+    depends on, the compiler included, and ``cxx`` is what the host rule
+    asks. Returns the ``cxx_override`` for ``compile_edges``, or None
+    without a pch.
+    """
+    if not pch_usable(cxx):
+        return None
+    if any(
+        tok == "-include" or tok.startswith("--include") or is_joined_include(tok)
+        for tok in cxxflags
+    ):
+        # $cxxflags expands first and GCC only loads a .gch for the first
+        # -include
+        _LOGGER.warning(
+            "A -include in the compiler flags prevents the precompiled header from "
+            "loading; compiling without it"
+        )
+        return None
+    log_pch_in_use()
+    source = write_pch_headers(build_dir, headers)
+    write_file_if_changed(
+        build_dir / PCH_SUM_NAME,
+        pch_identity([*cxxflags, *src_flags], src_dir, tuple(headers), identity) + "\n",
+    )
+    gch = _e(PCH_GCH_NAME)
+    # The checksum file changes with anything the .gch depends on
+    lines.append(f"build {gch}: pch {_e(source)} | {_e(PCH_SUM_NAME)}")
+    if src_flags:
+        lines.append(f"  flags = {' '.join(src_flags)}")
+    lines.append(f"srccxxflags = {' '.join([*src_flags, *pch_consumer_flags()])}")
+    return ("$srccxxflags", gch)
+
+
+def ar_rule_lines(ar: Path | str) -> list[str]:
+    return [
+        "rule ar",
+        f"  command = $python $buildtool ar {_q(ar)} $out $out.rsp",
+        "  rspfile = $out.rsp",
+        "  rspfile_content = $in_newline",
+        "  description = AR $out",
+    ]
+
+
+def compile_edges(
+    lines: list[str],
+    sources: list[Path],
+    root: Path,
+    group: str,
+    flags: str = "",
+    own_includes: str = "",
+    cxx_override: tuple[str, str] | None = None,
+) -> list[str]:
+    """Emit compile edges for ``sources``; return the object paths.
+
+    ``cxx_override`` is a (flags, implicit-dep) pair applied to C++ edges
+    only, replacing ``flags`` (used for the precompiled header).
+    """
+    objects = []
+    for src in sources:
+        rel = src.relative_to(root).as_posix()
+        obj = f"obj/{group}/{rel}.o"
+        escaped_obj = _e(obj)
+        kind = SOURCE_KIND_FOR_SUFFIX[src.suffix]
+        override = cxx_override if kind == "cxx" else None
+        implicit = f" | {override[1]}" if override else ""
+        lines.append(f"build {escaped_obj}: {kind} {_e(src)}{implicit}")
+        if own_includes:
+            lines.append(f"  own_includes = {own_includes}")
+        if edge_flags := override[0] if override else flags:
+            lines.append(f"  flags = {edge_flags}")
+        # Escaped once here: the returned paths only ever appear in build
+        # statements (archive/link inputs), which use ninja escaping
+        objects.append(escaped_obj)
+    return objects
+
+
+def library_edges(
+    lines: list[str], libraries: list[ArduinoLibrary], extra_flags: str = ""
+) -> tuple[list[str], list[str]]:
+    """Emit every library's compile and archive edges.
+
+    ``extra_flags`` (raw ninja text) precede each library's own flags.
+
+    Returns the archive names and the objects that link directly. A
+    library's own include dirs lead its compile lines, as PlatformIO searched
+    them first: the include path is one global list, so another library's
+    header of the same name would shadow them.
+    """
+    archives: list[str] = []
+    direct_objs: list[str] = []
+    for lib in libraries:
+        if not lib.sources:
+            # Header-only libraries are legitimate; the log makes an empty
+            # srcFilter or broken tree traceable before link errors do
+            _LOGGER.debug(
+                "Library %s has no source files; contributing includes only",
+                lib.name,
+            )
+            continue
+        objs = compile_edges(
+            lines,
+            lib.sources,
+            common_parent(lib.sources),
+            f"lib/{lib.name}",
+            flags=" ".join(filter(None, [extra_flags, *map(_shell_token, lib.flags)])),
+            own_includes=" ".join(f"-I{_q(d)}" for d in lib.include_dirs),
+        )
+        if not lib.lib_archive:
+            # libArchive: false / dot_a_linkage=false: hand the objects to
+            # the linker directly so unreferenced-but-required symbols
+            # (exception handlers, weak overrides) survive
+            direct_objs.extend(objs)
+            continue
+        archive = f"lib{lib.name}.a"
+        lines.append(f"build {_e(archive)}: ar {' '.join(objs)}")
+        archives.append(archive)
+    return archives, direct_objs
+
+
+# One build flag: the flag, plus its argument when that is a separate token
+Flag = tuple[str, ...]
+
+# Flags whose path operand is the next token; gcc also takes it glued on
+PATH_ARG_FLAGS = ("-include", "-imacros", "-isystem", "-iquote", "-idirafter")
+# Flags whose path operand is glued on
+PATH_PREFIXES = ("-I", "-L", *PATH_ARG_FLAGS)
+
+
+def _anchor(path: str, base: Path) -> str:
+    if not path or Path(path).is_absolute():
+        return path
+    return str(base / path)
+
+
+def anchor_path_flag(flag: Flag, base: Path) -> Flag:
+    """Anchor a flag's relative path operand at ``base``.
+
+    PlatformIO ran the compiler from the build path; ninja runs it from
+    ``.pioenvs/<name>``, where a relative operand would point elsewhere.
+    """
+    name, *args = flag
+    if args:
+        if name in PATH_ARG_FLAGS:
+            return (name, _anchor(args[0], base))
+        return flag
+    for prefix in PATH_PREFIXES:
+        if name.startswith(prefix):
+            return (prefix + _anchor(name[len(prefix) :], base),)
+    return flag

esphome/build_helpers/pch.py

@@ -0,0 +1,248 @@
+"""Shared precompiled header policy for the build backends."""
+
+from __future__ import annotations
+
+from collections.abc import Iterable, Sequence
+import hashlib
+import logging
+import os
+from pathlib import Path
+import posixpath
+import re
+import subprocess
+import sys
+
+from esphome.build_helpers.ccache import effective_ccache_basedir, parse_enable_env
+from esphome.const import PLATFORM_NRF52
+from esphome.helpers import write_file_if_changed
+
+_LOGGER = logging.getLogger(__name__)
+
+# The header and its sidecars live in the build directory
+PCH_HEADER_NAME = "esphome_pch.h"
+PCH_GCH_NAME = f"{PCH_HEADER_NAME}.gch"
+# ccache hashes this instead of the .gch; also the freshness stamp
+PCH_SUM_NAME = f"{PCH_GCH_NAME}.sum"
+# The include list the .gch is compiled from
+PCH_SOURCE_NAME = "esphome_pch_src.h"
+
+# GCC can skip a .gch without a diagnostic and read the header of the same
+# name, so that header is an error. Other tools get the include list.
+PCH_GUARD_TEXT = f"""\
+#if defined(__GNUC__) && !defined(__clang__) && !defined(__INTELLISENSE__)
+#error "The precompiled header was not loaded"
+#else
+#include "{PCH_SOURCE_NAME}"
+#endif
+"""
+
+# The cc1plus wrapper the PlatformIO script writes on arm64 macOS
+PCH_CC1_DIR = "pch_cc1"
+
+# What the PlatformIO script leaves in the project root, for cleanup
+PCH_ARTIFACT_NAMES = (PCH_HEADER_NAME, PCH_GCH_NAME, PCH_SUM_NAME, PCH_SOURCE_NAME)
+PCH_ARTIFACT_DIRS = (PCH_CC1_DIR,)
+
+# The core headers every backend precompiles
+PCH_DEFAULT_HEADERS = ("esphome/core/pch_prefix.h",)
+
+# PlatformIO platforms that do not take the pch script
+PCH_SCRIPT_EXCLUDED_PLATFORMS = frozenset(
+    {
+        PLATFORM_NRF52,
+    }
+)
+
+# What ccache needs to cache compiles that load a .gch
+_CCACHE_PCH_SLOPPINESS = ("pch_defines", "time_macros")
+
+# Both include forms: an angle include resolving under src/ enters the digest
+_INCLUDE_RE = re.compile(rb'^\s*#\s*include\s+["<]([^">]+)[">]', re.MULTILINE)
+
+
+def pch_enabled() -> bool:
+    """Precompiled-header knob: default on, ``ESPHOME_PCH_ENABLE=0`` opts out."""
+    return parse_enable_env("ESPHOME_PCH_ENABLE") is not False
+
+
+def pch_forced() -> bool:
+    """``ESPHOME_PCH_ENABLE=1``: wanted even where the host rule says no."""
+    return parse_enable_env("ESPHOME_PCH_ENABLE") is True
+
+
+# GCC bug 14940: before these releases the Windows loader maps a .gch only
+# at its saved address. First fixed release per major, 16 on always fixed;
+# PCH_WINDOWS_CMAKE_OLD_GCC and the pch_usable message spell the same table
+PCH_WINDOWS_GCC_FIXED = {14: (14, 4), 15: (15, 3)}
+PCH_WINDOWS_GCC_FIXED_DEFAULT = (16, 0)
+# The same rule for CMake, which alone knows the version before configure
+PCH_WINDOWS_CMAKE_OLD_GCC = (
+    "CMAKE_CXX_COMPILER_VERSION VERSION_LESS 14.4 OR "
+    "(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 15 AND "
+    "CMAKE_CXX_COMPILER_VERSION VERSION_LESS 15.3)"
+)
+
+
+def gcc_relocates_pch_on_windows(version: Sequence[int]) -> bool:
+    """Whether a GCC of this version loads a .gch on Windows."""
+    if not version:
+        return False
+    fixed = PCH_WINDOWS_GCC_FIXED.get(version[0], PCH_WINDOWS_GCC_FIXED_DEFAULT)
+    return tuple(version[:2]) >= fixed
+
+
+# GCC ends the first --version line with its version; clang names itself
+_VERSION_RE = re.compile(r"\d+(?:\.\d+)+")
+
+
+def gcc_version(cxx: Sequence[Path | str]) -> tuple[int, ...] | None:
+    """The GCC version from ``--version``: () when it cannot be read, None
+    for a compiler that is not GCC."""
+    try:
+        result = subprocess.run(
+            [*cxx, "--version"], capture_output=True, text=True, check=False
+        )
+    except OSError as err:
+        _LOGGER.debug("Cannot run %s: %s", cxx[0], err)
+        return ()
+    banner = result.stdout.partition("\n")[0]
+    if "clang" in banner.lower():
+        return None
+    found = _VERSION_RE.findall(banner)
+    return tuple(int(part) for part in found[-1].split(".")) if found else ()
+
+
+def pch_needs_gcc_check() -> bool:
+    """Windows host with the knob unset: the compiler version decides."""
+    return sys.platform == "win32" and parse_enable_env("ESPHOME_PCH_ENABLE") is None
+
+
+def pch_usable(cxx: Sequence[Path | str]) -> bool:
+    """The knob plus the host rule; ``ESPHOME_PCH_ENABLE=1`` skips the rule."""
+    if not pch_enabled():
+        return False
+    if not pch_needs_gcc_check():
+        return True
+    version = gcc_version(cxx)
+    if version is None or gcc_relocates_pch_on_windows(version):
+        return True
+    _LOGGER.info(
+        "GCC %s cannot load a precompiled header on Windows (GCC bug 14940, "
+        "fixed in 14.4, 15.3 and 16); compiling without it "
+        "(set ESPHOME_PCH_ENABLE=1 to force)",
+        ".".join(map(str, version)) or "of unknown version",
+    )
+    return False
+
+
+def pch_consumer_flags() -> list[str]:
+    """Flags a C++ src compile loads the pch with. The -include stays
+    relative: an absolute path would enter the ccache key."""
+    return ["-Winvalid-pch", "-Werror=invalid-pch", "-include", PCH_HEADER_NAME]
+
+
+def ccache_pch_env() -> dict[str, str]:
+    """What ccache needs to cache compiles that load a .gch, added to what
+    the user already set."""
+    if not pch_enabled():
+        return {}
+    sloppiness = [
+        item.strip()
+        for item in os.environ.get("CCACHE_SLOPPINESS", "").split(",")
+        if item.strip()
+    ]
+    sloppiness += [item for item in _CCACHE_PCH_SLOPPINESS if item not in sloppiness]
+    env = {"CCACHE_SLOPPINESS": ",".join(sloppiness)}
+    if "CCACHE_PCH_EXTSUM" not in os.environ:
+        env["CCACHE_PCH_EXTSUM"] = "true"
+    return env
+
+
+def pch_script_enabled() -> bool:
+    """Whether this PlatformIO build takes the pch script."""
+    from esphome.core import CORE
+
+    return pch_enabled() and CORE.target_platform not in PCH_SCRIPT_EXCLUDED_PLATFORMS
+
+
+def pch_header_text(include_headers: Iterable[str]) -> str:
+    """The prefix-header source: exactly these includes, in order."""
+    return "".join(f'#include "{name}"\n' for name in include_headers)
+
+
+def write_pch_headers(build_dir: Path, include_headers: Iterable[str]) -> Path:
+    """Write the guard header and the include list; return the latter,
+    which is what the .gch compiles from."""
+    write_file_if_changed(build_dir / PCH_HEADER_NAME, PCH_GUARD_TEXT)
+    source = build_dir / PCH_SOURCE_NAME
+    write_file_if_changed(source, pch_header_text(include_headers))
+    return source
+
+
+def _include_closure(src_dir: Path, roots: Iterable[str]) -> dict[str, bytes]:
+    """Include closure of ``roots``: src-relative name -> contents.
+
+    Resolution mirrors the compiler (includer's dir, then src root). No
+    #ifdef evaluation: including too much is the safe direction. Headers
+    outside ``src_dir`` are covered by the version strings of the caller.
+    """
+    seen: dict[str, bytes] = {}
+    stack: list[tuple[str, str]] = [(name, "") for name in roots]
+    while stack:
+        name, from_dir = stack.pop()
+        for candidate in (f"{from_dir}/{name}" if from_dir else name, name):
+            rel = posixpath.normpath(candidate)
+            if not rel.startswith("..") and (src_dir / rel).is_file():
+                break
+        else:
+            continue
+        if rel in seen:
+            continue
+        data = seen[rel] = (src_dir / rel).read_bytes()
+        parent = posixpath.dirname(rel)
+        stack.extend((inc.decode(), parent) for inc in _INCLUDE_RE.findall(data))
+    return seen
+
+
+def pch_checksum(
+    src_dir: Path, include_headers: Iterable[str], extra: Iterable[str]
+) -> str:
+    """Digest of the prefix header's include closure plus ``extra``."""
+    digest = hashlib.sha256()
+    closure = _include_closure(src_dir, include_headers)
+    for name in sorted(closure):
+        digest.update(name.encode())
+        digest.update(closure[name])
+        digest.update(b"\0")
+    for item in extra:
+        digest.update(item.encode())
+        digest.update(b"\0")
+    return digest.hexdigest()
+
+
+def pch_identity(
+    tokens: Iterable[str],
+    src_dir: Path,
+    include_headers: tuple[str, ...],
+    extra: Iterable[str],
+) -> str:
+    """The .sum digest: include closure, header text, ``extra`` and the
+    compile flags with the build path stripped, as ccache does."""
+    from esphome.core import CORE
+
+    flags = (
+        " ".join(tokens)
+        .replace(str(CORE.build_path), "")
+        .replace(effective_ccache_basedir(), "")
+    )
+    # The closure is sorted, so header order only enters via the text
+    return pch_checksum(
+        src_dir, include_headers, (pch_header_text(include_headers), *extra, flags)
+    )
+
+
+_DISABLE_HINT = " (set ESPHOME_PCH_ENABLE=0 to disable)"
+
+
+def log_pch_in_use() -> None:
+    _LOGGER.info("Compiling with a precompiled header%s", _DISABLE_HINT)

esphome/build_helpers/size_summary.py

@@ -0,0 +1,24 @@
+"""The PlatformIO-format size bar shared by the native toolchains."""
+
+from __future__ import annotations
+
+
+def format_bar(used: int, total: int) -> str:
+    """Match PlatformIO's ``_format_availale_bytes`` (sic, pioupload.py) exactly."""
+    pct_raw = used / total if total else 0
+    blocks = 10
+    filled = min(int(round(blocks * pct_raw)), blocks)
+    progress = "=" * filled
+    return (
+        f"[{progress:<{blocks}}] {pct_raw: 6.1%} "
+        f"(used {used:d} bytes from {total:d} bytes)"
+    )
+
+
+def print_size_line(label: str, used: int, total: int) -> None:
+    """One PlatformIO-format summary line (``RAM``/``Flash``).
+
+    The label padding is part of the format: ``script/ci_memory_impact_extract.py``
+    matches these lines verbatim.
+    """
+    print(f"{label + ':':<7}{format_bar(used, total)}")

esphome/build_helpers/tool_runner.py

@@ -0,0 +1,180 @@
+"""Run a native build tool (cmake, ninja) and relay its output.
+
+Output is read from a pipe so it can be filtered here: a child that inherits
+our stdout writes straight to the file descriptor, past any Python wrapper.
+"""
+
+from __future__ import annotations
+
+import codecs
+from contextlib import suppress
+import logging
+import os
+from pathlib import Path
+import re
+import shutil
+import subprocess
+import sys
+from typing import Any, TextIO
+
+from esphome.util import ANSI_ESCAPE, RedirectText, shlex_quote
+
+_LOGGER = logging.getLogger(__name__)
+
+# Windows code page identifier for UTF-8, as used by ``chcp 65001``.
+UTF8_CODEPAGE = 65001
+
+# Same pattern idf.py uses to spot ninja status lines (``is_progression``).
+_PROGRESS = re.compile(r"^\[\d+/\d+\]|.*\(\d+ \%\)$")
+_READ_SIZE = 65536
+
+
+def _get_kernel32() -> Any | None:
+    """Return the Windows kernel32 module, or None on any other platform."""
+    if sys.platform != "win32":
+        return None
+    import ctypes
+
+    return ctypes.windll.kernel32
+
+
+class Utf8Console:
+    """Keep an attached Windows console on UTF-8 while a build tool runs.
+
+    esp_idf_size draws its table with Unicode box characters, and CMake
+    re-decodes a child's output with the console code page, which garbles the
+    table on any page but UTF-8. A console already on UTF-8 is left alone so
+    an overlapping build never records UTF-8 as the page to go back to.
+    """
+
+    def __init__(self, kernel32: Any | None) -> None:
+        self._kernel32 = kernel32
+        self._codepages: tuple[int, int] | None = None
+
+    def __enter__(self) -> None:
+        kernel32 = self._kernel32
+        if kernel32 is None:
+            return
+        old_in = kernel32.GetConsoleCP()
+        old_out = kernel32.GetConsoleOutputCP()
+        # Both calls return 0 when no console is attached.
+        if not old_in or not old_out:
+            return
+        if old_in == UTF8_CODEPAGE and old_out == UTF8_CODEPAGE:
+            return
+        # Record first so a switch that fails part way is still undone.
+        self._codepages = (old_in, old_out)
+        kernel32.SetConsoleCP(UTF8_CODEPAGE)
+        kernel32.SetConsoleOutputCP(UTF8_CODEPAGE)
+
+    def __exit__(self, *exc_info: object) -> None:
+        if self._codepages is None:
+            return
+        old_in, old_out = self._codepages
+        self._codepages = None
+        self._kernel32.SetConsoleCP(old_in)
+        self._kernel32.SetConsoleOutputCP(old_out)
+
+
+def _fit_terminal(text: str) -> str:
+    """Elide the middle of ``text`` to fit the terminal, as idf.py does.
+
+    A width of 0 (a pipe, the dashboard) leaves the text whole.
+    """
+    width = shutil.get_terminal_size((0, 0)).columns
+    if not width:
+        return text
+    if width <= 3:
+        return "." * width
+    if len(text) >= width:
+        keep = (width - 3) // 2
+        return f"{text[:keep]}...{text[len(text) - keep :]}"
+    return text
+
+
+class ToolOutput(RedirectText):
+    """RedirectText that can collapse ninja status lines into one line.
+
+    With ``progress`` each ``[n/m]`` line overwrites the previous one, the
+    way idf.py shows a build.
+    """
+
+    def __init__(
+        self, out: TextIO, filter_lines: list[str] | None, progress: bool
+    ) -> None:
+        super().__init__(out, filter_lines=filter_lines)
+        self._progress = progress
+        self._on_progress_line = False
+
+    def _splits_lines(self) -> bool:
+        return self._progress or super()._splits_lines()
+
+    def _emit_line(self, line: str) -> None:
+        if self._progress and _PROGRESS.match(line):
+            if not self._is_filtered(line):
+                text = _fit_terminal(line.strip("\r\n"))
+                self._write_color_replace(f"\r{text}\x1b[K")
+                self._on_progress_line = True
+            return
+        self._end_progress_line()
+        super()._emit_line(line)
+
+    def _end_progress_line(self) -> None:
+        if self._on_progress_line:
+            self._on_progress_line = False
+            self._write_color_replace(os.linesep)
+
+    def drain(self) -> None:
+        super().drain()
+        # Called from cleanup, so a broken stream must not hide the exit code.
+        with suppress(OSError, ValueError):
+            self._end_progress_line()
+            self._out.flush()
+
+
+def run_build_tool(
+    cmd: list[str],
+    *,
+    cwd: Path,
+    env: dict[str, str],
+    filter_lines: list[str] | None = None,
+    progress: bool = False,
+    log_path: Path | None = None,
+) -> int:
+    """Run ``cmd`` and relay stdout and stderr, merged, to our stdout.
+
+    ``log_path`` also gets the full, unfiltered output without color codes, as
+    idf.py wrote its logs (its hint patterns expect plain text). Returns the
+    exit code.
+    """
+    _LOGGER.debug("Running: %s", " ".join(shlex_quote(arg) for arg in cmd))
+    _LOGGER.debug("  in directory: %s", cwd)
+    output = ToolOutput(sys.stdout, filter_lines, progress)
+    decoder = codecs.getincrementaldecoder("utf-8")(errors="replace")
+    if log_path is not None:
+        log_path.parent.mkdir(parents=True, exist_ok=True)
+    with (
+        Path(log_path or os.devnull).open("w", encoding="utf-8", newline="") as log,
+        Utf8Console(_get_kernel32()),
+        subprocess.Popen(
+            cmd,
+            cwd=cwd,
+            env=env,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.STDOUT,
+            close_fds=False,
+        ) as proc,
+    ):
+        try:
+            # read1 returns as soon as anything is available, so output
+            # streams while the tool runs.
+            while chunk := proc.stdout.read1(_READ_SIZE):
+                text = decoder.decode(chunk)
+                log.write(ANSI_ESCAPE.sub("", text))
+                output.write(text)
+            if tail := decoder.decode(b"", final=True):
+                log.write(ANSI_ESCAPE.sub("", tail))
+                output.write(tail)
+        finally:
+            output.drain()
+    return proc.returncode

esphome/build_helpers/tools_cache.py

@@ -0,0 +1,46 @@
+"""Machine-global tools cache location shared by the native backends."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+
+def tools_cache_path(env_var: str, subdir: str) -> Path:
+    """A backend's machine-global tools directory, with an env override.
+
+    A blank/whitespace override is treated as unset: ``Path("")`` resolves
+    to the CWD, which ``clean-all`` would then delete.
+    """
+    import platformdirs
+
+    from esphome.helpers import get_str_env
+
+    if prefix := get_str_env(env_var, "").strip():
+        # resolve(): a symlinked prefix would otherwise record a second
+        # spelling of the same paths in the build tree
+        return Path(prefix).expanduser().resolve()
+    # appauthor=False keeps the Windows path short (no vendor segment);
+    # deep IDF trees run into MAX_PATH otherwise
+    return (
+        Path(platformdirs.user_cache_dir("esphome", appauthor=False)) / subdir
+    ).resolve()
+
+
+# (env override, cache subdir) per native backend. writer.clean_all wipes
+# every entry via tools_cache_path, so listing a cache here is the single
+# step that registers it for removal; the backends' own path getters use
+# the same named pairs so the two cannot drift.
+IDF_TOOLS_CACHE = ("ESPHOME_ESP_IDF_PREFIX", "idf")
+SDK_NRF_TOOLS_CACHE = ("ESPHOME_SDK_NRF_PREFIX", "sdk-nrf")
+ARDUINO8266_TOOLS_CACHE = ("ESPHOME_ARDUINO8266_PREFIX", "arduino8266")
+# The host backend installs nothing; the entry only holds its ccache dir
+HOST_TOOLS_CACHE = ("ESPHOME_HOST_PREFIX", "host")
+# PlatformIO installs into its own dirs; the entry is its ccache dir itself
+PLATFORMIO_CCACHE = ("ESPHOME_PLATFORMIO_CCACHE_DIR", "platformio-ccache")
+TOOLS_CACHE_SPECS = (
+    IDF_TOOLS_CACHE,
+    SDK_NRF_TOOLS_CACHE,
+    ARDUINO8266_TOOLS_CACHE,
+    HOST_TOOLS_CACHE,
+    PLATFORMIO_CCACHE,
+)

esphome/bundle.py

@@ -20,6 +20,7 @@ from typing import Any
 
 from esphome import const, yaml_util
 from esphome.const import (
+    BUNDLE_EXTENSION,
     CONF_ESPHOME,
     CONF_EXTERNAL_COMPONENTS,
     CONF_INCLUDES,
@@ -29,12 +30,12 @@ from esphome.const import (
     CONF_TYPE,
 )
 from esphome.core import CORE, EsphomeError
+from esphome.util import filter_yaml_files
 
 _LOGGER = logging.getLogger(__name__)
 
 DOMAIN = "bundle"
 
-BUNDLE_EXTENSION = ".esphomebundle.tar.gz"
 MANIFEST_FILENAME = "manifest.json"
 CURRENT_MANIFEST_VERSION = 1
 MAX_DECOMPRESSED_SIZE = 500 * 1024 * 1024  # 500 MB
@@ -101,25 +102,21 @@ _KNOWN_FILE_EXTENSIONS = frozenset(
 )
 
 
-# Matches !secret references in YAML text.  An optional surrounding
-# quote pair around the key is allowed and ignored: YAML treats
-# ``!secret 'foo'`` and ``!secret foo`` as the same key.  This is
-# intentionally a simple regex scan rather than a YAML parse — it may
-# match inside comments or multi-line strings, which is the conservative
-# direction (include more secrets rather than fewer).
-_SECRET_RE = re.compile(r"""!secret\s+['"]?([^\s'"]+)""")
-
-
 def _find_used_secret_keys(yaml_files: list[Path]) -> set[str]:
     """Scan YAML files for ``!secret <key>`` references."""
     keys: set[str] = set()
     for fpath in yaml_files:
         try:
             text = fpath.read_text(encoding="utf-8")
-        except (OSError, UnicodeDecodeError):
+        except (OSError, UnicodeDecodeError) as err:
+            _LOGGER.warning(
+                "Could not scan %s for !secret references (%s); the bundled "
+                "secret set may be incomplete",
+                fpath,
+                err,
+            )
             continue
-        for match in _SECRET_RE.finditer(text):
-            keys.add(match.group(1))
+        keys |= yaml_util.find_secret_references(text)
     return keys
 
 
@@ -128,6 +125,9 @@ class BundleData:
     """Files components asked to include, keyed under DOMAIN in CORE.data."""
 
     extra_files: list[Path] = field(default_factory=list)
+    # Directories whose YAML files are scanned for !secret references but
+    # never bundled, e.g. git package checkouts the builder re-fetches.
+    secret_scan_dirs: set[Path] = field(default_factory=set)
     # Original config dir parsed from an extracted bundle's manifest.json,
     # kept in the path flavor of the machine the bundle was created on.
     # The checked flag makes the manifest lookup happen at most once per run;
@@ -155,6 +155,30 @@ def add_bundle_file(path: Path) -> None:
     _get_data().extra_files.append(CORE.relative_config_path(path))
 
 
+def add_secret_scan_dir(path: Path) -> None:
+    """Register a directory to scan for ``!secret`` references when bundling.
+
+    The directory's files are not added to the bundle. Components call this
+    for YAML the build consumes without bundling it — such as git-fetched
+    packages, which the builder re-fetches — so the secrets those files
+    reference are still shipped in the filtered secrets file.
+
+    A relative path is taken as relative to the config directory.
+    """
+    if not path.is_absolute():
+        path = CORE.relative_config_path(path)
+    _get_data().secret_scan_dirs.add(path)
+
+
+def _secret_scan_yaml_files() -> list[Path]:
+    """Return the YAML files inside registered secret-scan directories."""
+    return filter_yaml_files(
+        f
+        for scan_dir in _get_data().secret_scan_dirs
+        for f in yaml_util.find_files(scan_dir, "*")
+    )
+
+
 # Windows paths start with a drive letter or contain backslashes; POSIX
 # paths do neither in practice, so this is how the flavor of a recorded
 # path string is recognized on any host.
@@ -310,6 +334,7 @@ class ConfigBundleCreator:
         yaml_sources = [
             bf.source for bf in files if bf.source.suffix in (".yaml", ".yml")
         ]
+        yaml_sources.extend(_secret_scan_yaml_files())
         used_secret_keys = _find_used_secret_keys(yaml_sources)
         filtered_secrets = self._build_filtered_secrets(used_secret_keys)
 
@@ -393,7 +418,26 @@ class ConfigBundleCreator:
         must ship every candidate so the remote build can pick any one.
         """
         discovered = yaml_util.discover_user_yaml_files(self._config_path)
+        if discovered.load_errors:
+            _LOGGER.warning(
+                "Bundle may be incomplete; could not load all configuration files: %s",
+                "; ".join(discovered.load_errors),
+            )
+        if discovered.unresolved:
+            _LOGGER.warning(
+                "Bundle may be incomplete; %d !include path(s) use "
+                "substitutions and cannot be captured: %s",
+                len(discovered.unresolved),
+                ", ".join(discovered.unresolved),
+            )
         self._secrets_paths.update(discovered.secrets)
+        # A !secret inside a file this re-parse does not reach (for example
+        # a git-fetched package the builder re-fetches) still resolves
+        # against the config-dir secrets.yaml at build time, so always
+        # consider that file; filtering no-ops when no key matches.
+        default_secrets = self._config_dir / yaml_util.SECRET_YAML
+        if default_secrets.is_file():
+            self._secrets_paths.add(default_secrets.resolve())
         config_resolved = self._config_path.resolve()
         for fpath in discovered.files:
             if fpath == config_resolved:
@@ -719,11 +763,6 @@ def _validate_tar_members(tar: tarfile.TarFile, target_dir: Path) -> None:
             )
 
 
-def is_bundle_path(path: Path) -> bool:
-    """Check if a path looks like a bundle file."""
-    return path.name.lower().endswith(BUNDLE_EXTENSION)
-
-
 def _add_bytes_to_tar(tar: tarfile.TarFile, name: str, data: bytes) -> None:
     """Add in-memory bytes to a tar archive with deterministic metadata."""
     info = tarfile.TarInfo(name=name)

esphome/cli/__init__.py

@@ -0,0 +1,2 @@
+"""Commands of the esphome command line, one module each, imported by
+__main__ only when they run so that startup stays light."""

esphome/cli/rename.py

@@ -0,0 +1,164 @@
+"""``esphome rename``."""
+
+from __future__ import annotations
+
+import argparse
+from pathlib import Path
+import re
+
+from esphome import yaml_edit, yaml_util
+from esphome.const import (
+    ALLOWED_NAME_CHARS,
+    CONF_ESPHOME,
+    CONF_NAME,
+    CONF_SUBSTITUTIONS,
+)
+from esphome.core import CORE, EsphomeError
+from esphome.log import AnsiFore, color
+from esphome.types import ConfigType
+from esphome.util import ESPHOME_COMMAND, run_external_process, safe_print
+
+
+def _revert(new_path: Path, why: str) -> int:
+    """Say why the rename stopped and take the new file back; an orphan the
+    next attempt would trip over is reported."""
+    safe_print(color(AnsiFore.BOLD_RED, f"Rename failed: {why}"))
+    try:
+        new_path.unlink(missing_ok=True)
+    except OSError as err:
+        safe_print(color(AnsiFore.BOLD_RED, f"Could not remove {new_path}: {err}"))
+    return 1
+
+
+def command_rename(args: argparse.Namespace, config: ConfigType) -> int | None:
+    """Rename the device: a new file with the name line rewritten, validated
+    and installed, then the old file removed."""
+    new_name = args.name
+    for c in new_name:
+        if c not in ALLOWED_NAME_CHARS:
+            safe_print(
+                color(
+                    AnsiFore.BOLD_RED,
+                    f"'{c}' is an invalid character for names. Valid characters are: "
+                    f"{ALLOWED_NAME_CHARS} (lowercase, no spaces)",
+                )
+            )
+            return 1
+
+    yaml = yaml_util.load_yaml(CORE.config_path)
+
+    def name_edit() -> tuple[str, yaml_edit.LineEdit]:
+        """The name and the line to rewrite: the name's own line, or the
+        substitution's line it comes from, as a plain value in this file."""
+        esphome_conf = yaml.get(CONF_ESPHOME)
+        if not isinstance(esphome_conf, dict) or CONF_NAME not in esphome_conf:
+            raise EsphomeError(f"no '{CONF_ESPHOME}: {CONF_NAME}:' in the file")
+        old_name = str(esphome_conf[CONF_NAME])
+        mapping, field = esphome_conf, CONF_NAME
+        if match := re.match(r"^\$\{?([a-zA-Z0-9_]+)\}?$", old_name):
+            mapping, field = yaml.get(CONF_SUBSTITUTIONS), match.group(1)
+            if not isinstance(mapping, dict) or field not in mapping:
+                raise EsphomeError(f"the substitution '{field}' is not in the file")
+            old_name = str(mapping[field])
+        # Only read here; the rewritten text goes to a new file, so the
+        # source may live anywhere the config path points to
+        source = yaml_edit.source_of(mapping, field)
+        if source is None or source[0].resolve() != CORE.config_path.resolve():
+            raise EsphomeError(f"'{field}' was not read from {CORE.config_path}")
+        doc, line_no = source
+        text = yaml_edit.line_at(doc, line_no)
+        if (line_match := yaml_edit.field_line_re(field, old_name).match(text)) is None:
+            raise EsphomeError(f"'{field}' is not a plain value on {doc}:{line_no + 1}")
+        # The new value is always quoted, whatever the old line had
+        return old_name, yaml_edit.LineEdit(
+            doc, line_no, text, yaml_edit.rewrite(line_match, new_name, '"')
+        )
+
+    try:
+        old_name, edit = name_edit()
+    except EsphomeError as err:
+        safe_print(
+            color(
+                AnsiFore.BOLD_RED,
+                f"Complex YAML files cannot be automatically renamed: {err}",
+            )
+        )
+        return 1
+
+    # ``new_name == old_name`` (after substitution resolution) is
+    # a no-op rewrite that would still queue a pointless re-flash.
+    # Catch it before the path-equality check below — covers the
+    # case where the config filename doesn't match the device name
+    # (e.g. ``weird-file.yaml`` whose ``esphome.name`` is
+    # ``kitchen``; running ``esphome rename weird-file.yaml kitchen``
+    # would otherwise just re-flash the same hostname).
+    if new_name == old_name:
+        safe_print(
+            color(
+                AnsiFore.BOLD_RED,
+                f"'{new_name}' is already the device's name.",
+            )
+        )
+        return 1
+
+    new_path: Path = CORE.config_dir / (new_name + ".yaml")
+    if new_path.resolve() == CORE.config_path.resolve():
+        safe_print(
+            color(
+                AnsiFore.BOLD_RED,
+                f"'{new_name}' is already the device's name.",
+            )
+        )
+        return 1
+    if new_path.exists():
+        safe_print(
+            color(
+                AnsiFore.BOLD_RED,
+                f"Cannot rename: {new_path} already exists. "
+                "Refusing to overwrite an existing configuration.",
+            )
+        )
+        return 1
+    safe_print(
+        f"Updating {color(AnsiFore.CYAN, str(CORE.config_path))} to {color(AnsiFore.CYAN, str(new_path))}"
+    )
+    print()
+
+    try:
+        yaml_edit.write_keeping_mode(
+            new_path,
+            yaml_edit.rewritten_text(yaml_edit.read_text(CORE.config_path), [edit]),
+            like=CORE.config_path,
+        )
+    except EsphomeError as err:
+        return _revert(new_path, str(err))
+
+    if run_external_process(*ESPHOME_COMMAND, "config", str(new_path)) != 0:
+        return _revert(new_path, "the new configuration does not validate")
+
+    cli_args = [
+        "run",
+        str(new_path),
+        "--no-logs",
+        "--device",
+        CORE.address,
+    ]
+
+    if args.dashboard:
+        cli_args.insert(0, "--dashboard")
+
+    try:
+        rc = run_external_process(*ESPHOME_COMMAND, *cli_args)
+    except KeyboardInterrupt:
+        rc = 1
+    if rc != 0:
+        return _revert(
+            new_path,
+            "the install did not finish; the device may already run the new name",
+        )
+
+    CORE.config_path.unlink()
+
+    safe_print(color(AnsiFore.BOLD_GREEN, "SUCCESS"))
+    print()
+    return 0

esphome/codegen.py

@@ -25,22 +25,29 @@ from esphome.cpp_generator import (  # noqa: F401
     add,
     add_build_flag,
     add_build_unflag,
+    add_cmake_arg,
     add_cxx_build_flag,
     add_define,
     add_global,
     add_library,
     add_platformio_option,
+    extern_progmem_array,
     get_variable,
     get_variable_with_full_id,
+    is_static_pointer,
     is_template,
     new_Pvariable,
     new_variable,
     process_lambda,
     progmem_array,
+    progmem_string,
     safe_exp,
     set_cpp_standard,
+    shared_progmem_array,
+    shared_progmem_string,
     statement,
     static_const_array,
+    static_function,
     templatable,
     variable,
     with_local_variable,
@@ -49,10 +56,13 @@ from esphome.cpp_helpers import (  # noqa: F401
     build_registry_entry,
     build_registry_list,
     extract_registry_entry_config,
+    get_slot_count,
     gpio_pin_expression,
     past_safe_mode,
     register_component,
     register_parented,
+    set_setup_priority,
+    slot_counter,
 )
 from esphome.cpp_types import (  # noqa: F401
     NAN,
@@ -60,7 +70,6 @@ from esphome.cpp_types import (  # noqa: F401
     Application,
     Component,
     ComponentPtr,
-    Controller,
     EntityBase,
     EntityCategory,
     ESPTime,
@@ -74,6 +83,7 @@ from esphome.cpp_types import (  # noqa: F401
     StringRef,
     arduino_json_ns,
     bool_,
+    char,
     const_char_ptr,
     double,
     esphome_ns,

esphome/compiled_config.py

@@ -1,26 +1,193 @@
 """Validated-config cache for the upload/logs fast path.
 
-compile dumps the validated config to <data_dir>/storage/<file>.validated.yaml;
+compile dumps the validated config to <data_dir>/storage/<file>.validated.json;
 the next upload/logs for that YAML reuses it instead of running the full
-read_config pipeline. YAML round-trip (yaml_util.dump/load_yaml) keeps
-!lambda/!include/IDs/paths intact; mtime gates staleness.
+read_config pipeline. The cache is deliberately lossy: only ``!lambda``
+bodies survive typed (``Lambda``); IDs, time periods, MAC/IP addresses,
+paths, UUIDs and enums store the same string form the YAML dumper
+produced for them. JSON additionally coerces non-str dict keys to
+strings; validated configs only use string keys (every schema key
+validator is ``cv.string``). mtime gates staleness.
 """
 
 from __future__ import annotations
 
+import json
 import logging
 from pathlib import Path
+from typing import Any
 
-from esphome.core import CORE
+from esphome.const import __version__ as ESPHOME_VERSION
+from esphome.core import CORE, EsphomeError, Lambda
 from esphome.helpers import write_file
-from esphome.storage_json import StorageJSON, ext_storage_path
+from esphome.storage_json import StorageJSON, ext_storage_path, storage_path
 from esphome.types import ConfigType
 
 _LOGGER = logging.getLogger(__name__)
 
+# Bump when the on-disk shape changes; a mismatched version falls back
+# to read_config. The envelope also stamps the writing esphome version:
+# after an upgrade the cache holds the previous release's validation, so
+# it falls back once and the re-save self-heals.
+_CACHE_VERSION = 1
+_LAMBDA_KEY = "__esphome_lambda__"
+
 
 def compiled_config_path(config_filename: str) -> Path:
     """Path to the cached validated config alongside the storage sidecar."""
+    return CORE.data_dir / "storage" / f"{config_filename}.validated.json"
+
+
+def save_compiled_config(config: ConfigType) -> None:
+    """Write the validated-config cache. Always-write so mtime stays fresh.
+
+    Mode 0600 because config validation resolved !secret inline.
+    Failures are non-fatal: the fast path falls back to read_config.
+    """
+    try:
+        # The legacy YAML cache holds inline-resolved secrets and nothing
+        # reads it anymore; drop it even when the write below fails. A
+        # failed removal leaves resolved secrets on disk, so it warns.
+        try:
+            _legacy_compiled_config_path(CORE.config_filename).unlink(missing_ok=True)
+        except OSError as err:
+            _LOGGER.warning(
+                "Could not remove the legacy validated-config cache: %s", err
+            )
+        rendered = json.dumps(
+            {"v": _CACHE_VERSION, "esphome": ESPHOME_VERSION, "config": config},
+            separators=(",", ":"),
+            default=_json_default,
+        )
+        write_file(compiled_config_path(CORE.config_filename), rendered, private=True)
+    except TypeError as err:
+        # Structural, not transient: this config can never cache (e.g. a
+        # non-basic dict key), so every upload/logs pays the slow path.
+        _LOGGER.warning("Cannot cache the validated config: %s", err)
+    except Exception as err:  # noqa: BLE001  # pylint: disable=broad-except
+        # Likely persistent (permissions, full disk): every upload/logs
+        # pays the slow path until it clears, so surface it.
+        _LOGGER.warning("Skipping compiled config cache write: %s", err)
+
+
+def save_compiled_config_and_sidecar(config: ConfigType) -> None:
+    """Refresh the cache from the upload/logs fallback (CORE.config must be set).
+
+    The cache is only written when a complete sidecar is on disk:
+    load_compiled_config can't use it otherwise, and it holds resolved
+    secrets.
+    """
+    if _refresh_sidecar():
+        save_compiled_config(config)
+
+
+def _refresh_sidecar() -> bool:
+    """Ensure a complete sidecar is on disk; True when one is.
+
+    Writes one (without claiming a build) when missing or wizard-only.
+    Failures are non-fatal; the next upload/logs pays the slow path again.
+    """
+    try:
+        path = storage_path()
+        try:
+            old = StorageJSON.load_strict(path)
+        except Exception as err:  # noqa: BLE001  # pylint: disable=broad-except
+            # Present but unreadable: it may hold a real build's metadata,
+            # and a fresh rewrite would also stop the next compile from
+            # cleaning a possibly incoherent build tree.
+            _LOGGER.warning(
+                "Not caching: storage sidecar %s is unreadable (%s)", path, err
+            )
+            return False
+        if old is not None and old.can_apply_to_core():
+            if (
+                old.toolchain is not None
+                and CORE.toolchain is not None
+                and old.toolchain != CORE.toolchain.value
+            ):
+                # Platforms normalize toolchain-sensitive keys differently;
+                # never cache a config validated under a different toolchain
+                # than the compile's
+                _LOGGER.debug(
+                    "Not caching: config validated with toolchain %r but the "
+                    "last compile used %r",
+                    CORE.toolchain.value,
+                    old.toolchain,
+                )
+                return False
+            # Compile-written; nothing to refresh.
+            return True
+        if CORE.build_path is not None and CORE.build_path.exists():
+            # An unvalidated build tree: its absent or mismatched sidecar
+            # is what makes the next compile wipe it, so don't vouch for
+            # a build this run never saw.
+            _LOGGER.warning(
+                "Not caching: build tree %s has no matching sidecar; "
+                "'esphome compile' will settle it",
+                CORE.build_path,
+            )
+            return False
+        new = StorageJSON.from_esphome_core(CORE, old, claim_build=False)
+        if not new.can_apply_to_core():
+            _LOGGER.warning("Not caching: rebuilt storage sidecar is still incomplete")
+            return False
+        new.save(path)
+        return True
+    except (OSError, EsphomeError) as err:
+        # write_file wraps OSError into EsphomeError. Persistent
+        # (unwritable storage dir), so surface that every upload/logs
+        # pays the slow path.
+        _LOGGER.warning("Could not refresh the storage sidecar: %s", err)
+    except Exception:  # noqa: BLE001  # pylint: disable=broad-except
+        # A structural bug; keep the traceback so it isn't mistaken
+        # for the I/O failure above.
+        _LOGGER.warning(
+            "Unexpected error refreshing the storage sidecar", exc_info=True
+        )
+    return False
+
+
+def load_compiled_config(conf_path: Path) -> ConfigType | None:
+    """Load the cached validated config and apply storage metadata to CORE.
+
+    Returns None (caller falls back to read_config) when the cache is
+    missing, older than the source YAML, unparseable, a different cache
+    version, or the sidecar is incomplete. The loaded config carries no
+    source ranges; callers must not feed it into read_config/write_cpp.
+    """
+    cache_path = compiled_config_path(conf_path.name)
+    if not _cache_is_fresh(cache_path, conf_path):
+        return None
+
+    try:
+        envelope = json.loads(
+            cache_path.read_text(encoding="utf-8"), object_hook=_decode_object
+        )
+    except (OSError, ValueError) as err:
+        _LOGGER.debug("Ignoring unreadable compiled config cache: %s", err)
+        return None
+
+    if (
+        not isinstance(envelope, dict)
+        or envelope.get("v") != _CACHE_VERSION
+        or envelope.get("esphome") != ESPHOME_VERSION
+        or not isinstance(config := envelope.get("config"), dict)
+    ):
+        _LOGGER.debug("Ignoring compiled config cache with a foreign envelope")
+        return None
+
+    storage = StorageJSON.load(ext_storage_path(conf_path.name))
+    if storage is None or not storage.can_apply_to_core():
+        _LOGGER.debug("Ignoring compiled config cache: sidecar missing or incomplete")
+        return None
+    storage.apply_to_core()
+    return config
+
+
+# Remove before 2027.8: by then every maintained install has saved the
+# JSON cache at least once and dropped its legacy YAML file.
+def _legacy_compiled_config_path(config_filename: str) -> Path:
+    """Path of the pre-JSON YAML cache; only ever removed."""
     return CORE.data_dir / "storage" / f"{config_filename}.validated.yaml"
 
 
@@ -32,45 +199,21 @@ def _cache_is_fresh(cache_path: Path, source_path: Path) -> bool:
         return False
 
 
-def save_compiled_config(config: ConfigType) -> None:
-    """Write the validated-config cache. Always-write so mtime stays fresh.
+def _json_default(value: Any) -> Any:
+    """Mirror ESPHomeDumper's representers: Lambda stays typed, the rest
+    stringify (IDs, time periods, MAC/IP addresses, paths, UUIDs, enums).
 
-    Mode 0600 because show_secrets=True resolves !secret inline.
-    Failures are non-fatal: the fast path falls back to read_config.
+    IncludeFile/Extend/Remove have no JSON mirror and would stringify
+    wrong, but none survive validation (config.py's packages merge and
+    the substitution pass consume them) so no guard is spent on them.
     """
-    from esphome import yaml_util
-
-    try:
-        rendered = yaml_util.dump(config, show_secrets=True)
-        write_file(compiled_config_path(CORE.config_filename), rendered, private=True)
-    except Exception as err:  # noqa: BLE001  # pylint: disable=broad-except
-        _LOGGER.debug("Skipping compiled config cache write: %s", err)
+    if isinstance(value, Lambda):
+        return {_LAMBDA_KEY: value.value}
+    return str(value)
 
 
-def load_compiled_config(conf_path: Path) -> ConfigType | None:
-    """Load the cached validated config and apply storage metadata to CORE.
-
-    Returns None (caller falls back to read_config) when the cache is
-    missing, older than the source YAML, unparseable, or the sidecar
-    is incomplete.
-    """
-    cache_path = compiled_config_path(conf_path.name)
-    if not _cache_is_fresh(cache_path, conf_path):
-        return None
-
-    from esphome import yaml_util
-
-    try:
-        config = yaml_util.load_yaml(cache_path, clear_secrets=False)
-    except Exception:  # noqa: BLE001  # pylint: disable=broad-except
-        return None
-
-    storage = StorageJSON.load(ext_storage_path(conf_path.name))
-    if storage is None:
-        return None
-    # apply_to_core assumes a real compile wrote the sidecar; wizard-only
-    # sidecars leave both of these unset and can't drive upload/logs.
-    if not storage.core_platform and not storage.target_platform:
-        return None
-    storage.apply_to_core()
-    return config
+def _decode_object(obj: dict[str, Any]) -> Any:
+    """Revive the Lambda sentinel; every other mapping passes through."""
+    if len(obj) == 1 and isinstance(value := obj.get(_LAMBDA_KEY), str):
+        return Lambda(value)
+    return obj

esphome/component_aliases.py

@@ -0,0 +1,11 @@
+"""Component alias registry.
+
+Generated by script/build_alias_registry.py - do not edit manually.
+See the component-alias section of esphome/loader.py.
+"""
+
+# alias -> (canonical component, removal version or None)
+COMPONENT_ALIASES: dict[str, tuple[str, str | None]] = {
+    "esp32_improv": ("improv_ble", "2027.4.0"),
+    "rp2040": ("rp2", "2027.7.0"),
+}

esphome/components/a01nyub/__init__.py

@@ -1 +1,2 @@
 CODEOWNERS = ["@MrSuicideParrot"]
+DOMAIN = "a01nyub"

esphome/components/a01nyub/a01nyub.cpp

@@ -6,7 +6,7 @@
 
 namespace esphome::a01nyub {
 
-static const char *const TAG = "a01nyub.sensor";
+ESPHOME_LOG_TAG(TAG, "a01nyub.sensor");
 
 void A01nyubComponent::loop() {
   uint8_t data;

esphome/components/a01nyub/sensor.py

@@ -6,6 +6,7 @@ from esphome.const import (
     STATE_CLASS_MEASUREMENT,
     UNIT_METER,
 )
+from esphome.types import ConfigType
 
 CODEOWNERS = ["@MrSuicideParrot"]
 DEPENDENCIES = ["uart"]
@@ -35,7 +36,7 @@ FINAL_VALIDATE_SCHEMA = uart.final_validate_device_schema(
 )
 
 
-async def to_code(config):
+async def to_code(config: ConfigType) -> None:
     var = await sensor.new_sensor(config)
     await cg.register_component(var, config)
     await uart.register_uart_device(var, config)

esphome/components/a02yyuw/__init__.py

@@ -1 +1,2 @@
 CODEOWNERS = ["@TH-Braemer"]
+DOMAIN = "a02yyuw"

esphome/components/a02yyuw/a02yyuw.cpp

@@ -6,7 +6,7 @@
 
 namespace esphome::a02yyuw {
 
-static const char *const TAG = "a02yyuw.sensor";
+ESPHOME_LOG_TAG(TAG, "a02yyuw.sensor");
 
 void A02yyuwComponent::loop() {
   uint8_t data;

esphome/components/a02yyuw/sensor.py

@@ -6,6 +6,7 @@ from esphome.const import (
     STATE_CLASS_MEASUREMENT,
     UNIT_MILLIMETER,
 )
+from esphome.types import ConfigType
 
 CODEOWNERS = ["@TH-Braemer"]
 DEPENDENCIES = ["uart"]
@@ -35,7 +36,7 @@ FINAL_VALIDATE_SCHEMA = uart.final_validate_device_schema(
 )
 
 
-async def to_code(config):
+async def to_code(config: ConfigType) -> None:
     var = await sensor.new_sensor(config)
     await cg.register_component(var, config)
     await uart.register_uart_device(var, config)

esphome/components/a4988/__init__.py

@@ -0,0 +1 @@
+DOMAIN = "a4988"

esphome/components/a4988/a4988.cpp

@@ -3,7 +3,7 @@
 
 namespace esphome::a4988 {
 
-static const char *const TAG = "a4988.stepper";
+ESPHOME_LOG_TAG(TAG, "a4988.stepper");
 
 void A4988::setup() {
   if (this->sleep_pin_ != nullptr) {

esphome/components/a4988/stepper.py

@@ -3,6 +3,7 @@ import esphome.codegen as cg
 from esphome.components import stepper
 import esphome.config_validation as cv
 from esphome.const import CONF_DIR_PIN, CONF_ID, CONF_SLEEP_PIN, CONF_STEP_PIN
+from esphome.types import ConfigType
 
 a4988_ns = cg.esphome_ns.namespace("a4988")
 A4988 = a4988_ns.class_("A4988", stepper.Stepper, cg.Component)
@@ -17,7 +18,7 @@ CONFIG_SCHEMA = stepper.STEPPER_SCHEMA.extend(
 ).extend(cv.COMPONENT_SCHEMA)
 
 
-async def to_code(config):
+async def to_code(config: ConfigType) -> None:
     var = cg.new_Pvariable(config[CONF_ID])
     await cg.register_component(var, config)
     await stepper.register_stepper(var, config)

esphome/components/absolute_humidity/__init__.py

@@ -1 +1,2 @@
 CODEOWNERS = ["@DAVe3283"]
+DOMAIN = "absolute_humidity"

esphome/components/absolute_humidity/absolute_humidity.cpp

@@ -3,7 +3,7 @@
 
 namespace esphome::absolute_humidity {
 
-static const char *const TAG{"absolute_humidity.sensor"};
+ESPHOME_LOG_TAG(TAG, "absolute_humidity.sensor");
 
 void AbsoluteHumidityComponent::setup() {
   this->temperature_sensor_->add_on_state_callback([this](float state) {

esphome/components/absolute_humidity/sensor.py

@@ -9,6 +9,7 @@ from esphome.const import (
     STATE_CLASS_MEASUREMENT,
     UNIT_GRAMS_PER_CUBIC_METER,
 )
+from esphome.types import ConfigType
 
 absolute_humidity_ns = cg.esphome_ns.namespace("absolute_humidity")
 AbsoluteHumidityComponent = absolute_humidity_ns.class_(
@@ -43,7 +44,7 @@ CONFIG_SCHEMA = (
 )
 
 
-async def to_code(config):
+async def to_code(config: ConfigType) -> None:
     var = await sensor.new_sensor(config)
     await cg.register_component(var, config)
 

esphome/components/ac_dimmer/__init__.py

@@ -0,0 +1 @@
+DOMAIN = "ac_dimmer"