[serial_proxy] Add USB identity query for USB-bridged ports

Add SERIAL_PROXY_PORT_TYPE_USB_SERIAL, derived automatically when a
port's uart_id resolves to a usb_uart channel (never set by the user),
and a SerialProxyGetUsbInfoRequest/Response pair (IDs 153/154) that
reads VID/PID/bcdDevice and the manufacturer/product/serial strings
live from the descriptors the USB host stack caches, so a client can
identify the attached device before subscribing. Ports that are not
USB_SERIAL answer NOT_SUPPORTED; an unplugged device answers with
connected=false. ZigbeeProxyRequest moves to ID 155 (expected merge
order: set_mode, USB info, zigbee).

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

@@ -1,39 +0,0 @@
-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=$(python -c 'from esphome.components.esp8266 import RECOMMENDED_ARDUINO_FRAMEWORK_VERSION as f; from esphome.arduino8266.framework import TOOLCHAIN_VERSION as t; print(f"{f}-{t}")')
-        [ -n "$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/workflows/ci.yml

@@ -102,8 +102,6 @@ jobs:
       device-builder: ${{ steps.determine.outputs.device-builder }}
       esp32-platformio: ${{ steps.determine.outputs.esp32-platformio }}
       esp32-platformio-components: ${{ steps.determine.outputs.esp32-platformio-components }}
-      esp8266-native: ${{ steps.determine.outputs.esp8266-native }}
-      esp8266-native-components: ${{ steps.determine.outputs.esp8266-native-components }}
       changed-components: ${{ steps.determine.outputs.changed-components }}
       changed-components-with-tests: ${{ steps.determine.outputs.changed-components-with-tests }}
       directly-changed-components-with-tests: ${{ steps.determine.outputs.directly-changed-components-with-tests }}
@@ -167,8 +165,6 @@ jobs:
           echo "device-builder=$(echo "$output" | jq -r '.device_builder')" >> $GITHUB_OUTPUT
           echo "esp32-platformio=$(echo "$output" | jq -r '.esp32_platformio')" >> $GITHUB_OUTPUT
           echo "esp32-platformio-components=$(echo "$output" | jq -r '.esp32_platformio_components')" >> $GITHUB_OUTPUT
-          echo "esp8266-native=$(echo "$output" | jq -r '.esp8266_native')" >> $GITHUB_OUTPUT
-          echo "esp8266-native-components=$(echo "$output" | jq -r '.esp8266_native_components')" >> $GITHUB_OUTPUT
           echo "changed-components=$(echo "$output" | jq -c '.changed_components')" >> $GITHUB_OUTPUT
           echo "changed-components-with-tests=$(echo "$output" | jq -c '.changed_components_with_tests')" >> $GITHUB_OUTPUT
           echo "directly-changed-components-with-tests=$(echo "$output" | jq -c '.directly_changed_components_with_tests')" >> $GITHUB_OUTPUT
@@ -187,32 +183,6 @@ jobs:
           path: .temp/components_graph.json
           key: components-graph-${{ hashFiles('esphome/components/**/*.py') }}
 
-  seed-esp8266-native-cache:
-    name: Seed the esp8266 native toolchain cache
-    runs-on: ubuntu-24.04
-    needs:
-      - common
-    # PR-branch cache saves are invisible to other PRs, so dev pushes seed
-    # the shared entry test-esp8266-native restores. Only dev: the composite
-    # action saves nowhere else, so a beta/release push would download the
-    # toolchain and discard it.
-    if: github.event_name == 'push' && github.ref == 'refs/heads/dev'
-    timeout-minutes: 15
-    steps:
-      - name: Check out code from GitHub
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
-      - name: Restore Python
-        uses: ./.github/actions/restore-python
-        with:
-          python-version: ${{ env.DEFAULT_PYTHON }}
-          cache-key: ${{ needs.common.outputs.cache-key }}
-      - name: Cache the native toolchain
-        uses: ./.github/actions/cache-arduino8266
-      - name: Install the native toolchain
-        run: |
-          . venv/bin/activate
-          python -c "from esphome.arduino8266.framework import check_and_install; from esphome.components.esp8266 import RECOMMENDED_ARDUINO_FRAMEWORK_VERSION; check_and_install(RECOMMENDED_ARDUINO_FRAMEWORK_VERSION)"
-
   ci-custom:
     name: Run script/ci-custom
     runs-on: ubuntu-24.04
@@ -1258,7 +1228,7 @@ jobs:
 
           # compile validates config first, so a separate config pass is
           # redundant for this smoke test. ESP-IDF framework via PlatformIO:
-          python3 script/test_build_components.py -e compile -t esp32-idf -c "$TEST_COMPONENTS" -f --toolchain platformio --fail-on-no-tests
+          python3 script/test_build_components.py -e compile -t esp32-idf -c "$TEST_COMPONENTS" -f --toolchain platformio
 
           echo ""
           echo "ESP-IDF-via-PlatformIO build passed! Starting Arduino smoke test..."
@@ -1267,40 +1237,6 @@ jobs:
           # Arduino framework via PlatformIO (only components with an esp32-ard test are built):
           python3 script/test_build_components.py -e compile -t esp32-ard -c "$TEST_COMPONENTS" -f --toolchain platformio
 
-  test-esp8266-native:
-    name: Test esp8266 components with the native toolchain
-    runs-on: ubuntu-24.04
-    needs:
-      - common
-      - determine-jobs
-    if: github.event_name == 'pull_request' && needs.determine-jobs.outputs.esp8266-native == 'true'
-    env:
-      # Computed by script/determine-jobs.py (ESP8266_NATIVE_TEST_COMPONENTS)
-      TEST_COMPONENTS: ${{ needs.determine-jobs.outputs.esp8266-native-components }}
-    steps:
-      - name: Check out code from GitHub
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
-
-      - name: Restore Python
-        uses: ./.github/actions/restore-python
-        with:
-          python-version: ${{ env.DEFAULT_PYTHON }}
-          cache-key: ${{ needs.common.outputs.cache-key }}
-
-      - name: Cache the native toolchain
-        uses: ./.github/actions/cache-arduino8266
-
-      - name: Run native toolchain compile test
-        run: |
-          . venv/bin/activate
-
-          echo "Testing components: $TEST_COMPONENTS"
-          echo ""
-
-          # ESP8266 Arduino built directly (no PlatformIO); compile validates
-          # config first, so a separate config pass is redundant.
-          python3 script/test_build_components.py -e compile -t esp8266-ard -c "$TEST_COMPONENTS" -f --toolchain arduino --fail-on-no-tests
-
   device-builder:
     name: Test downstream esphome/device-builder
     runs-on: ubuntu-24.04
@@ -1663,7 +1599,6 @@ jobs:
     needs:
       - common
       - seed-apt-cache
-      - seed-esp8266-native-cache
       - determine-jobs
       - ci-custom
       - pylint
@@ -1679,7 +1614,6 @@ jobs:
       - clang-tidy-esp32-variants
       - test-build-components-split
       - test-esp32-platformio
-      - test-esp8266-native
       - device-builder
       - memory-impact-target-branch
       - memory-impact-pr-branch

esphome/__main__.py

@@ -817,9 +817,7 @@ def write_cpp_file() -> int:
         from esphome.build_gen import espidf
 
         espidf.write_project()
-    elif not CORE.using_native_toolchain:
-        # Other native builds generate their project at compile time;
-        # never write a platformio.ini for them
+    else:
         from esphome.build_gen import platformio
 
         platformio.write_project()
@@ -861,14 +859,20 @@ def compile_program(args: ArgsProtocol, config: ConfigType) -> int:
         toolchain.create_factory_bin()
         toolchain.create_ota_bin()
         toolchain.create_elf_copy()
-        from esphome.build_helpers.idedata import warn_if_idedata_missing
+        from esphome.build_helpers.idedata import IDEDATA_BEST_EFFORT_ERRORS
 
-        warn_if_idedata_missing(toolchain.get_idedata)
-    elif CORE.using_native_toolchain:
-        raise EsphomeError(
-            f"Toolchain '{CORE.toolchain.value}' resolved but no platform "
-            "backend claimed the build"
-        )
+        try:
+            if toolchain.get_idedata() is None:
+                _LOGGER.warning("No idedata was generated for this build")
+        except IDEDATA_BEST_EFFORT_ERRORS as err:
+            # The firmware already built; an idedata failure must not fail
+            # a successful build.
+            _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)
     else:
         from esphome.platformio import toolchain
 
@@ -971,15 +975,12 @@ def upload_using_esptool(
 
     if file is not None:
         flash_images = [FlashImage(path=file, offset="0x0")]
-    elif (native := _native_toolchain_module()) is not None:
-        # Every native backend supplies its own 0x0 flash image (bootloader
-        # and partitions included where the target needs them)
-        image = native.get_factory_firmware_path()
-        if not image.is_file():
-            raise EsphomeError(
-                f"{image} does not exist; compile the configuration first"
-            )
-        flash_images = [FlashImage(path=image, offset="0x0")]
+    elif CORE.using_toolchain_esp_idf:
+        from esphome.espidf import toolchain
+
+        flash_images = [
+            FlashImage(path=toolchain.get_factory_firmware_path(), offset="0x0")
+        ]
     else:
         from esphome.platformio import toolchain
 
@@ -1949,39 +1950,15 @@ def command_update_all(args: ArgsProtocol) -> int | None:
     return run_multiple_configs(files, build_command)
 
 
-# Native build backend per (target platform, toolchain). Keyed here rather
-# than through a platform hook so the serial upload/logs fast path never
-# imports the platform component package (see the esp32 variant comment in
-# upload_using_esptool); the platform half comes from CORE.data the same way.
-_NATIVE_TOOLCHAIN_MODULES = {
-    ("esp32", Toolchain.ESP_IDF): "esphome.espidf.toolchain",
-    ("esp8266", Toolchain.ARDUINO): "esphome.arduino8266.toolchain",
-}
-
-
-def _native_toolchain_module():
-    """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)
-
-
 def command_idedata(args: ArgsProtocol, config: ConfigType) -> int:
     import json
 
-    native_toolchain = _native_toolchain_module()
+    if CORE.using_toolchain_esp_idf:
+        # Native ESP-IDF derives idedata from the build's compile_commands.json,
+        # so the configuration must already be compiled.
+        from esphome.espidf import toolchain as espidf_toolchain
 
-    if native_toolchain is not None:
-        # Native toolchains derive idedata from the build's
-        # compile_commands.json, so the configuration must already be compiled.
-        idedata = native_toolchain.get_idedata()
+        idedata = espidf_toolchain.get_idedata()
         if idedata is None:
             _LOGGER.error(
                 "No idedata available; compile the configuration first",
@@ -2020,17 +1997,6 @@ def command_analyze_memory(args: ArgsProtocol, config: ConfigType) -> int:
     from esphome.analyze_memory.cli import MemoryAnalyzerCLI
     from esphome.analyze_memory.ram_strings import RamStringsAnalyzer
 
-    # Refuse an unsupported toolchain before paying for a full compile
-    native_toolchain = _native_toolchain_module()
-    if native_toolchain is None and not CORE.using_toolchain_platformio:
-        _LOGGER.error(
-            "analyze-memory is not supported with the '%s' toolchain on %s; "
-            "re-run with --toolchain platformio",
-            CORE.toolchain.value if CORE.toolchain else "unresolved",
-            CORE.target_platform,
-        )
-        return 1
-
     # Always compile to ensure fresh data (fast if no changes - just relinks)
     exit_code = write_cpp(config)
     if exit_code != 0:
@@ -2042,31 +2008,13 @@ def command_analyze_memory(args: ArgsProtocol, config: ConfigType) -> int:
 
     # Get idedata for analysis
     idedata = None
-    if native_toolchain is not None:
-        objdump = native_toolchain.get_objdump_path()
-        readelf = native_toolchain.get_readelf_path()
-        for tool in (objdump, readelf):
-            if not tool.is_file():
-                # The analyzer would silently fall back to host binutils,
-                # which cannot read the target ELF. clean-all is heavy for
-                # ESP-IDF, so suggest a recompile first.
-                _LOGGER.error(
-                    "%s is missing; the toolchain install may be incomplete "
-                    "(recompile, or run 'esphome clean-all' if it persists)",
-                    tool,
-                )
-                return 1
-        objdump_path = str(objdump)
-        readelf_path = str(readelf)
+    if CORE.using_toolchain_esp_idf:
+        from esphome.espidf import toolchain
 
-        firmware_elf = native_toolchain.get_elf_path()
-        if not firmware_elf.is_file():
-            # The analyzer swallows tool failures, so a missing ELF would
-            # produce an exit-0 zeroed report
-            _LOGGER.error(
-                "%s is missing; compile the configuration first", firmware_elf
-            )
-            return 1
+        objdump_path = str(toolchain.get_objdump_path())
+        readelf_path = str(toolchain.get_readelf_path())
+
+        firmware_elf = toolchain.get_elf_path()
     else:
         from esphome.platformio import toolchain
 

esphome/arduino8266/framework.py

@@ -19,7 +19,6 @@ from typing import NamedTuple
 
 from esphome.build_helpers.ccache import ccache_defaults_env
 from esphome.build_helpers.ninja import find_ninja
-from esphome.build_helpers.pch import ccache_pch_env
 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
@@ -157,6 +156,4 @@ def ccache_env(ccache: str | None) -> dict[str, str]:
     """
     if ccache is None:
         return {}
-    env = ccache_defaults_env(get_arduino8266_tools_path() / "ccache")
-    env.update(ccache_pch_env())
-    return env
+    return ccache_defaults_env(get_arduino8266_tools_path() / "ccache")

esphome/arduino8266/toolchain.py

@@ -1,329 +0,0 @@
-"""Native Arduino ESP8266 build driver (the PlatformIO ``run`` equivalent)."""
-
-from __future__ import annotations
-
-import json
-import logging
-from pathlib import Path
-import subprocess
-from typing import Any
-
-from esphome.arduino8266 import framework
-from esphome.build_helpers.ccache import resolve_ccache_path
-from esphome.const import (
-    CONF_COMPILE_PROCESS_LIMIT,
-    CONF_ESPHOME,
-    KEY_CORE,
-    KEY_FRAMEWORK_VERSION,
-)
-from esphome.core import CORE, EsphomeError
-from esphome.helpers import write_file_if_changed
-from esphome.types import ConfigType
-
-_LOGGER = logging.getLogger(__name__)
-
-# ESP8266 user RAM (matches upload.maximum_ram_size in every board manifest)
-_MAX_RAM_SIZE = 81920
-
-
-def _warn_ignored_platformio_options() -> None:
-    """Warn for component-added platformio options the native build drops.
-
-    The consumed set is exported by core/config.py next to the routing that
-    stores these options, so the two cannot drift; YAML upload_speed never
-    reaches CORE.platformio_options here.
-    """
-    from esphome.core.config import NATIVE_ARDUINO_CONSUMED_PIO_OPTIONS
-
-    consumed = NATIVE_ARDUINO_CONSUMED_PIO_OPTIONS
-    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 'arduino' toolchain",
-                key,
-            )
-
-
-_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:
-    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.build_gen import arduino8266 as build_gen
-
-    _warn_ignored_platformio_options()
-    paths = framework.check_and_install(CORE.data[KEY_CORE][KEY_FRAMEWORK_VERSION])
-    # Resolved once per build: the resolution probes PATH and spawns the
-    # runnability check, and three consumers need the same answer
-    ccache = resolve_ccache_path()
-    ninja_changed = build_gen.write_project(paths, ccache)
-
-    build_dir = get_build_dir()
-    env = framework.get_build_env(paths.toolchain, ccache)
-
-    # Regenerate the compile DB before the build (a pure function of
-    # build.ninja); skip only when it is at least as fresh as build.ninja
-    # (an interrupted previous run may have rewritten the manifest without
-    # regenerating the DB).
-    compdb = build_dir / "compile_commands.json"
-    compdb_stamp = build_dir / ".compile_commands.stamp"
-    ninja_file = build_dir / "build.ninja"
-    # Freshness rides a stamp: the DB itself is written through
-    # write_file_if_changed (its mtime feeds get_idedata's cache), so a
-    # regeneration with identical content would stay "stale" forever
-    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(paths.ninja, build_dir, env)
-        compdb_stamp.touch()
-
-    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, not the default statement: a generator defect that
-    # drops them fails loudly with "unknown target" instead of a green
-    # no-op run that leaves stale artifacts in place
-    targets = ["firmware.factory.bin", "firmware.ota.bin"]
-    cmd += targets
-
-    # A dry-run probe keeps a no-op rebuild quiet: ninja would only print
-    # "no work to do". A freshly rewritten manifest all but guarantees work,
-    # so skip the probe (and its full stat pass) on that path. cwd instead
-    # of -C also drops the "Entering directory" banner on real builds.
-    skip_build = False
-    if not ninja_changed:
-        probe = subprocess.run(
-            [str(paths.ninja), "-n", *targets],
-            cwd=build_dir,
-            env=env,
-            capture_output=True,
-            text=True,
-            check=False,
-            close_fds=False,
-        )
-        if probe.stderr.strip():
-            # A load-time diagnostic (e.g. "multiple rules generate X")
-            # flags a generator bug; the skip branch would otherwise
-            # swallow it forever
-            _LOGGER.warning("ninja: %s", probe.stderr.strip())
-        if probe.returncode != 0:
-            # An unknown target here is the defective-manifest case; fall
-            # through to the real build so the error prints attributably
-            _LOGGER.debug("ninja probe failed; running the full build")
-        skip_build = probe.returncode == 0 and "no work to do" in probe.stdout
-    if skip_build:
-        _LOGGER.debug("ninja: nothing to rebuild")
-    else:
-        _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 a manifest missing the explicit targets above;
-    # existence covers the remaining hole (a rule that ran but wrote
-    # elsewhere). The factory/ota copies are what upload and OTA consume.
-    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):
-        # The cause was already warned; name the consequence so a build
-        # contributing no RAM/Flash metric is visible to 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 _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", "c", "cxx", "asm"],
-        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 in get_idedata() stays valid.
-    write_file_if_changed(compdb, result.stdout)
-
-
-def _parse_app_size(build_dir: Path, paths: framework.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:
-        # UnicodeDecodeError: a truncated/corrupt script must degrade to
-        # the same warning, never abort an already-linked build
-        _LOGGER.warning("Cannot read linker script for the Flash summary: %s", err)
-        return None
-    app_size = segment_length(ld_text, "irom0_0_seg")
-    if app_size is None:
-        _LOGGER.warning("irom0_0_seg not found in %s; skipping Flash summary", ld_path)
-        return None
-    if app_size == 0:
-        _LOGGER.warning(
-            "irom0_0_seg has zero length in %s; skipping Flash summary", ld_path
-        )
-        return None
-    return app_size
-
-
-def _print_size_summary(build_dir: Path, paths: framework.InstalledPaths) -> bool:
-    """Print the PlatformIO-shaped RAM/Flash lines; False when skipped.
-
-    The exact shape (including the bar) is parsed by
-    ``script/ci_memory_impact_extract.py``; ``print_size_line`` matches it.
-    """
-    from esphome.build_helpers.size_summary import print_size_line
-
-    size_tool = _toolchain_tool("size")
-    try:
-        result = subprocess.run(
-            [str(size_tool), "-A", "-d", str(get_elf_path())],
-            capture_output=True,
-            text=True,
-            check=False,
-            close_fds=False,
-        )
-    except OSError 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
-    if result.returncode != 0:
-        _LOGGER.warning("Could not summarize firmware size: %s", result.stderr)
-        return False
-    sections: dict[str, int] = {}
-    for line in result.stdout.splitlines():
-        parts = line.split()
-        if len(parts) >= 2 and parts[0].startswith("."):
-            try:
-                sections[parts[0]] = int(parts[1])
-            except ValueError:
-                # An unparsed RAM/Flash section trips the missing-sections
-                # guard below, so no total is built on a dropped value
-                _LOGGER.warning("Unparsable size output for section %s", parts[0])
-    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 anything: a RAM line without
-    # its Flash line would let CI's memory-impact extraction sum the two
-    # metrics over different build counts (_parse_app_size already warned).
-    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
-
-
-# Sentinel: "resolve for me"; None is a real value meaning disabled.
-_CCACHE_UNRESOLVED: Any = object()
-
-
-def get_idedata(ccache: str | None = _CCACHE_UNRESOLVED) -> dict | None:
-    """Derive idedata from the build's compile_commands.json.
-
-    Same contract as ``espidf.toolchain.get_idedata``: the fields IDE
-    integrations, clang-tidy, and the memory analyzer expect.
-    """
-    from esphome.build_helpers.idedata import load_or_build_idedata
-
-    if ccache is _CCACHE_UNRESOLVED:
-        # Deliberately uncached: env/PATH can change between builds in a
-        # long-lived host process
-        ccache = resolve_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(ccache) if ccache else None,
-    )

esphome/build_gen/espidf.py

@@ -4,14 +4,6 @@ import json
 import logging
 from pathlib import Path
 
-from esphome.build_helpers import pch
-from esphome.build_helpers.pch import (
-    PCH_DEFAULT_HEADERS,
-    PCH_HEADER_NAME,
-    mark_pch_emitted,
-    pch_enabled,
-    pch_header_text,
-)
 from esphome.components.esp32 import (
     get_esp32_variant,
     get_excluded_builtin_components,
@@ -287,67 +279,9 @@ idf_component_register(
 target_link_options(${{COMPONENT_LIB}} PUBLIC
     {link_opts_str}
 )
-{_pch_cmake()}"""
-
-
-def _pch_cmake() -> str:
-    """The src component's precompiled-header block (C++ TUs only).
-
-    The -include stays relative (resolved from the compiler cwd, the build
-    dir); an absolute path would poison ccache keys.
-    """
-    if not pch_enabled():
-        return ""
-    return f"""
-# ESPHome precompiled header (see esphome/build_helpers/pch.py).
-# OBJECT_DEPENDS is on the header, not the .gch: pch-baked headers drop
-# out of TU depfiles, and prepare_pch() touches the header on rebuild.
-target_compile_options(${{COMPONENT_LIB}} PRIVATE
-    "$<$<COMPILE_LANGUAGE:CXX>:-Winvalid-pch>"
-    "$<$<COMPILE_LANGUAGE:CXX>:-include>"
-    "$<$<COMPILE_LANGUAGE:CXX>:{PCH_HEADER_NAME}>"
-)
-set_source_files_properties(${{app_sources}} PROPERTIES
-    OBJECT_DEPENDS "${{CMAKE_BINARY_DIR}}/{PCH_HEADER_NAME}")
 """
 
 
-def discard_pch() -> None:
-    """Drop the pch sidecars in the IDF build dir."""
-    pch.discard_pch(CORE.relative_build_path("build"))
-
-
-def prepare_pch() -> None:
-    """Build the .gch right before ninja, after every reconfigure, so the
-    compile_commands.json flags and the sdkconfig are the settled ones."""
-    if not pch_enabled():
-        # Self-cleaning escape hatch: drop any previously built .gch
-        pch.discard_pch(CORE.relative_build_path("build"))
-        return
-    sdkconfig_path = CORE.relative_build_path(f"sdkconfig.{CORE.name}")
-    try:
-        sdkconfig = sdkconfig_path.read_text(encoding="utf-8")
-    except OSError as err:
-        # Fail closed: the sdkconfig is the .sum's only config identity for
-        # sdkconfig.h-only options; a stand-in marker would collide
-        _LOGGER.warning(
-            "Could not read %s; compiling without the pch: %s", sdkconfig_path, err
-        )
-        pch.discard_pch(CORE.relative_build_path("build"))
-        return
-    pch.prepare_pch(
-        CORE.relative_build_path("build"),
-        PCH_DEFAULT_HEADERS,
-        (
-            str(idf_version()),
-            CORE.cpp_standard or "",
-            sdkconfig,
-            *get_project_compile_flags(),
-            *get_project_cxx_compile_flags(),
-        ),
-    )
-
-
 def write_project(
     minimal: bool = False, builtin_components: list[str] | None = None
 ) -> None:
@@ -367,14 +301,6 @@ def write_project(
         get_component_cmakelists(),
     )
 
-    if pch_enabled():
-        write_file_if_changed(
-            CORE.relative_build_path("build", PCH_HEADER_NAME),
-            pch_header_text(PCH_DEFAULT_HEADERS),
-        )
-        # Consumers carry the -include; gate the ccache relaxation on it
-        mark_pch_emitted()
-
     # Snapshot the exclusion set so has_outdated_files() can trigger a
     # discovery reconfigure when it changes. Excluded components never
     # register in project_description.json, so re-including one (e.g. a

esphome/build_helpers/ccache.py

@@ -87,19 +87,6 @@ def ccache_defaults_env(cache_dir: Path) -> dict[str, str]:
         "CCACHE_DIR": str(cache_dir),
         "CCACHE_NOHASHDIR": "true",
         "CCACHE_DEPEND": "1",
-        # A user value wins via the filter below
-        "CCACHE_BASEDIR": effective_ccache_basedir(),
+        "CCACHE_BASEDIR": str(Path(CORE.build_path).resolve()),
     }
     return {k: v for k, v in defaults.items() if k not in os.environ}
-
-
-def effective_ccache_basedir() -> str:
-    """The prefix ccache rewrites out of hashed paths: a user CCACHE_BASEDIR
-    wins, else the resolved build path (matching ccache_defaults_env)."""
-    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
-    # Unset or degenerate ("", "/", relative): fall back to the build path
-    return str(Path(CORE.build_path).resolve())

esphome/build_helpers/idedata.py

@@ -11,7 +11,6 @@ consumers (IDE integration, clang-tidy) expect:
 
 from __future__ import annotations
 
-from collections.abc import Callable
 import json
 import logging
 import os
@@ -22,8 +21,6 @@ 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 = (
@@ -34,36 +31,13 @@ IDEDATA_BEST_EFFORT_ERRORS = (
     ValueError,
 )
 
+_LOGGER = logging.getLogger(__name__)
 
-def warn_if_idedata_missing(get_idedata: Callable[[], dict | None]) -> None:
-    """Run an idedata generator, downgrading any failure to a warning.
-
-    Shared by the native backends: the firmware already built, so a missing
-    or broken idedata must not fail a successful build.
-    """
-    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,
-        )
-        if isinstance(err, (EsphomeError, OSError)):
-            # Routine environmental failures keep the detail at debug
-            _LOGGER.debug("Idedata failure detail", exc_info=True)
-        else:
-            # LookupError/ValueError/RuntimeError smell like a parsing bug;
-            # a permanently masked traceback would hide it on every build
-            _LOGGER.warning("Idedata failure detail", exc_info=True)
-
-
-# C++ translation-unit suffixes.
-CXX_SOURCE_SUFFIXES = (".cpp", ".cc", ".cxx")
+# 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_SOURCE_SUFFIXES, ".c", ".o", ".S", ".s")
+_INPUT_FILE_SUFFIXES = (*_CXX_SUFFIXES, ".c", ".o", ".S", ".s")
 # Path marker identifying an ESPHome source translation unit.
 _ESPHOME_SRC_MARKER = "/src/esphome/"
 
@@ -72,11 +46,11 @@ 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_SOURCE_SUFFIXES
+        _CXX_SUFFIXES
     )
 
 
-def split_command(command: str) -> list[str]:
+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``.
@@ -112,7 +86,7 @@ def split_command(command: str) -> list[str]:
         ctypes.windll.kernel32.LocalFree(argv)
 
 
-def expand_response_files(tokens: list[str], directory: Path) -> list[str]:
+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
@@ -127,8 +101,8 @@ def expand_response_files(tokens: list[str], directory: Path) -> list[str]:
                 rf = directory / rf
             try:
                 out.extend(
-                    expand_response_files(
-                        split_command(rf.read_text(encoding="utf-8")), directory
+                    _expand_response_files(
+                        _split_command(rf.read_text(encoding="utf-8")), directory
                     )
                 )
                 continue
@@ -147,7 +121,7 @@ def _pick_entry(entries: list[dict]) -> dict:
         if _is_esphome_src(entry["file"]):
             return entry
     for entry in entries:
-        if entry["file"].endswith(CXX_SOURCE_SUFFIXES):
+        if entry["file"].endswith(_CXX_SUFFIXES):
             return entry
     raise ValueError("no C++ translation unit found in compile_commands.json")
 
@@ -157,25 +131,16 @@ def _pick_entry(entries: list[dict]) -> dict:
 _LAUNCHER_STEMS = frozenset({"ccache", "sccache", "distcc", "icecc", "buildcache"})
 
 
-def is_launcher(token: str) -> bool:
+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)
+    tokens = _expand_response_files(_split_command(entry["command"]), directory)
 
     def _include(raw: str) -> str:
         # Resolve against the entry's ``directory`` so cached idedata works
@@ -191,7 +156,7 @@ def parse_entry(
     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("-"):
+    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])
@@ -204,23 +169,11 @@ def parse_entry(
     defines: list[str] = []
     includes: list[str] = []
     cxx_flags: list[str] = []
-    unresolved_force_includes: 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 == "-include" or is_joined_include(tok):
-            # Re-anchor only names next to the compile (the pch); a name
-            # meant for the -I chain must stay untouched
-            raw = next(it, "") if tok == "-include" else tok[len("-include") :]
-            if not raw:
-                _LOGGER.warning("Dropping -include with no argument")
-            elif Path(resolved := _include(raw)).is_file():
-                cxx_flags.extend(("-include", resolved))
-            else:
-                unresolved_force_includes.append(raw)
-                cxx_flags.extend(("-include", raw))
         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.
@@ -239,14 +192,6 @@ def parse_entry(
             pass  # input/output files
         else:
             cxx_flags.append(tok)
-    for raw in unresolved_force_includes:
-        # A deleted build artifact would otherwise surface only downstream
-        if not any((Path(inc) / raw).is_file() for inc in includes):
-            _LOGGER.warning(
-                "-include %s found neither next to the compile nor on the "
-                "include path; cached idedata may not resolve it",
-                raw,
-            )
     return cxx_path, defines, includes, cxx_flags
 
 
@@ -311,7 +256,7 @@ def _cache_usable(cached: object) -> bool:
     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):
+    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)
@@ -359,7 +304,7 @@ def load_or_build_idedata(
 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):
+    if _is_launcher(cxx_path):
         raise EsphomeError(
             f"compile_commands.json names the launcher {cxx_path} as the "
             "compiler; the compile database is unusable"

esphome/build_helpers/pch.py

@@ -1,423 +0,0 @@
-"""Shared precompiled-header policy for the build backends.
-
-The prefix either mirrors the TUs' own force-includes (ESP8266) or is a
-curated core-header set (ESP-IDF). ``esphome: includes:`` sources receive
-it too; Arduino.h visibility there is intended (esphome#8693).
-"""
-
-from __future__ import annotations
-
-from collections.abc import Iterable
-from dataclasses import dataclass
-import hashlib
-import json
-import logging
-import os
-from pathlib import Path
-import posixpath
-import re
-import stat
-import subprocess
-
-from esphome.build_helpers.ccache import effective_ccache_basedir, parse_enable_env
-from esphome.build_helpers.idedata import (
-    CXX_SOURCE_SUFFIXES,
-    expand_response_files,
-    is_launcher,
-    split_command,
-)
-
-_DOMAIN = "pch"
-
-
-@dataclass
-class _PCHData:
-    emitted: bool = False
-
-
-def _pch_data() -> _PCHData:
-    from esphome.core import CORE
-
-    if _DOMAIN not in CORE.data:
-        CORE.data[_DOMAIN] = _PCHData()
-    return CORE.data[_DOMAIN]
-
-
-def mark_pch_emitted() -> None:
-    """Record that this build's consumers reference the pch."""
-    _pch_data().emitted = True
-
-
-_LOGGER = logging.getLogger(__name__)
-
-# The header and its .gch/.sum sidecars live in the build directory.
-PCH_HEADER_NAME = "esphome_pch.h"
-
-# Every artifact the pch machinery can leave behind, for cleanup.
-PCH_ARTIFACT_NAMES = (
-    PCH_HEADER_NAME,
-    f"{PCH_HEADER_NAME}.gch",
-    f"{PCH_HEADER_NAME}.gch.sum",
-    f"{PCH_HEADER_NAME}.gch.failed",
-)
-
-# The core defines header every backend anchors its prefix on.
-PCH_CORE_HEADER = "esphome/core/defines.h"
-
-# Prefix-header contents for backends that inject a curated set (rather
-# than mirroring the TUs' own force-includes), defines.h first so USE_*
-# macros exist for the rest. Deliberately hard-coded: frequency-derived
-# sets measured no better and kept selecting headers that cannot compile
-# standalone (X-macro, platform-variant). Every entry must be safe to
-# include first in an empty TU. Caveat: application.h/automation.h become
-# ambiently visible, so a TU missing those #includes still builds on such
-# backends; ESPHOME_PCH_ENABLE=0 restores the strict view.
-PCH_DEFAULT_HEADERS = (
-    PCH_CORE_HEADER,
-    "esphome/core/component.h",
-    "esphome/core/helpers.h",
-    "esphome/core/log.h",
-    "esphome/core/application.h",
-    "esphome/core/automation.h",
-)
-
-# ccache cannot hash through a .gch; CCACHE_PCH_EXTSUM makes it hash the
-# .sum sidecar instead of the .gch bytes, which are not reproducible.
-# Keep in sync with the literals in platformio/pch.py.script.
-_CCACHE_PCH_ENV = {
-    "CCACHE_SLOPPINESS": "pch_defines,time_macros",
-    "CCACHE_PCH_EXTSUM": "true",
-}
-
-# Both include forms: an angle include resolving under src/ must enter the
-# digest too; ones that do not resolve simply end the walk
-# Compiler failures that clear on their own must not latch the .failed marker
-_TRANSIENT_ERRORS = ("No space left", "Cannot allocate", "Resource temporarily")
-
-_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 ccache_pch_env() -> dict[str, str]:
-    """Settings ccache needs to cache compiles that consume the .gch;
-    empty unless this build actually emitted one. User-set values win.
-    Native backends export these process-wide; only time_macros affects
-    non-pch TUs."""
-    if not (pch_enabled() and _pch_data().emitted):
-        return {}
-    extsum = os.environ.get("CCACHE_PCH_EXTSUM")
-    if extsum is not None and extsum.strip().lower() not in ("1", "true", "yes", "on"):
-        # ccache then hashes the non-reproducible .gch bytes: permanent misses
-        _LOGGER.warning("CCACHE_PCH_EXTSUM=%s disables pch caching", extsum)
-    env = {k: v for k, v in _CCACHE_PCH_ENV.items() if k not in os.environ}
-    user_sloppiness = os.environ.get("CCACHE_SLOPPINESS")
-    if user_sloppiness is not None and (
-        missing := [
-            t
-            for t in ("pch_defines", "time_macros")
-            if t not in {tok.strip() for tok in user_sloppiness.split(",")}
-        ]
-    ):
-        # Without these ccache declines every pch-consuming compile
-        env["CCACHE_SLOPPINESS"] = ",".join((user_sloppiness, *missing))
-        _LOGGER.warning(
-            "Adding %s to CCACHE_SLOPPINESS so ccache can cache compiles "
-            "that use the precompiled header",
-            ",".join(missing),
-        )
-    return env
-
-
-def pch_extra_scripts() -> list[str]:
-    """The extra_scripts entries a PlatformIO platform registers for the
-    pch; empty when disabled (the script itself has no enable check)."""
-    return ["post:pch.py"] if pch_enabled() else []
-
-
-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 _resolves(path: Path) -> bool:
-    """False when missing; other stat failures propagate (identity unknown,
-    unlike is_file(), which would silently drop the header)."""
-    try:
-        return stat.S_ISREG(path.stat().st_mode)
-    except (FileNotFoundError, NotADirectoryError):
-        return False
-
-
-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); names
-    outside ``src_dir`` end the walk and are versioned by the caller. No
-    #ifdef evaluation: over-approximating is the safe direction.
-    """
-    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 _resolves(src_dir / rel):
-                break
-        else:
-            continue
-        if rel in seen:
-            continue
-        try:
-            data = (src_dir / rel).read_bytes()
-        except OSError as err:
-            # A marker would truncate the transitive walk; fail closed
-            _LOGGER.warning("Could not read %s for the pch checksum: %s", rel, err)
-            raise
-        seen[rel] = data
-        parent = posixpath.dirname(rel)
-        stack.extend(
-            # surrogateescape: a non-UTF-8 name just fails to resolve
-            (inc.decode(errors="surrogateescape"), 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 standing in for the .gch in ccache's hash: the include closure
-    of the prefix header plus caller-supplied identity strings (versioned
-    install paths, flags). Raises OSError when a header's identity cannot
-    be established at all; callers must then compile without a pch."""
-    digest = hashlib.sha256()
-    closure = _include_closure(src_dir, include_headers)
-    for name in sorted(closure):
-        digest.update(name.encode(errors="surrogateescape"))
-        digest.update(closure[name])
-        digest.update(b"\0")
-    for item in extra:
-        digest.update(item.encode(errors="surrogateescape"))
-        digest.update(b"\0")
-    return digest.hexdigest()
-
-
-# Tokens dropped when retargeting a TU's flags at the prefix header
-# (the pch compile must not touch depfiles)
-_PCH_STRIP_FLAGS_WITH_ARG = frozenset({"-o", "-c", "-MT", "-MF", "-MQ"})
-_PCH_STRIP_FLAGS = frozenset({"-MD", "-MMD", "-MP", "-MM", "-M"})
-
-
-def pch_compile_command(
-    build_dir: Path, header: Path, gch: Path
-) -> tuple[list[str], Path] | None:
-    """The exact src C++ flags from compile_commands.json retargeted at the
-    header, with the directory they resolve against (relative -I paths must
-    be expanded and executed from the same root); None (logged) when no
-    configured C++ TU is available yet."""
-    from esphome.core import CORE
-
-    try:
-        entries = json.loads(
-            (build_dir / "compile_commands.json").read_text(encoding="utf-8")
-        )
-    except (OSError, json.JSONDecodeError) as err:
-        # Configure already succeeded, so an unusable DB is a real anomaly
-        _LOGGER.warning("No usable compile database, skipping pch: %s", err)
-        return None
-    if not isinstance(entries, list):
-        _LOGGER.warning("Malformed compile database, skipping pch")
-        return None
-    # CMake may spell paths through a symlink differently than CORE does
-    # (macOS /tmp vs /private/tmp), so compare resolved paths
-    src_root = Path(CORE.relative_src_path()).resolve()
-    entry = next(
-        (
-            e
-            for e in entries
-            if isinstance(e, dict)
-            and isinstance(e.get("file"), str)
-            and e["file"].endswith(CXX_SOURCE_SUFFIXES)
-            and Path(e["file"]).resolve().is_relative_to(src_root)
-        ),
-        None,
-    )
-    if entry is None:
-        _LOGGER.warning("No src C++ entry in the compile database, skipping pch")
-        return None
-    directory = entry.get("directory")
-    cmd_dir = Path(directory) if isinstance(directory, str) and directory else build_dir
-    command = entry.get("command")
-    tokens = expand_response_files(
-        split_command(command if isinstance(command, str) else ""), cmd_dir
-    )
-    # A DB recorded with ccache enabled prefixes the compiler with the
-    # launcher; the .gch must be compiled directly
-    if tokens and is_launcher(tokens[0]):
-        tokens = tokens[1:]
-    if not tokens:
-        # "arguments"-style or empty entries must skip, not spawn "-x ..."
-        _LOGGER.warning("Compile database entry has no usable command, skipping pch")
-        return None
-    args: list[str] = []
-    arg_it = iter(tokens)
-    for tok in arg_it:
-        if tok in _PCH_STRIP_FLAGS_WITH_ARG:
-            next(arg_it, None)
-            continue
-        if tok in _PCH_STRIP_FLAGS:
-            continue
-        if tok == "-include":
-            # Drop only the injected prefix; user force-includes must reach
-            # the .gch compile or GCC rejects it over the macro mismatch
-            inc = next(arg_it, "")
-            if not inc.endswith(PCH_HEADER_NAME):
-                args.extend(("-include", inc))
-            continue
-        args.append(tok)
-    return [*args, "-x", "c++-header", "-c", str(header), "-o", str(gch)], cmd_dir
-
-
-def _log_pch_in_use() -> None:
-    # The only place a user can discover the knob; emitted only once a
-    # .gch is actually fresh or being built
-    _LOGGER.info(
-        "Compiling with a precompiled header (set ESPHOME_PCH_ENABLE=0 to disable)"
-    )
-
-
-def _read_stamp(path: Path) -> str:
-    """A corrupt sidecar must read as stale, not kill the pch forever."""
-    try:
-        return path.read_text(encoding="utf-8").strip()
-    except (OSError, UnicodeDecodeError):
-        return ""
-
-
-def discard_pch(build_dir: Path) -> None:
-    """Remove the pch sidecars so a stale .gch is never consumed.
-
-    Bumps the header only when a .gch was actually removed: TUs compiled
-    against it have incomplete depfiles, while a repeat failure with no
-    .gch must not force a full rebuild every build.
-    """
-    header = build_dir / PCH_HEADER_NAME
-    gch = Path(f"{header}.gch")
-    had_gch = gch.is_file()
-    gch.unlink(missing_ok=True)
-    Path(f"{gch}.sum").unlink(missing_ok=True)
-    if had_gch and header.is_file():
-        os.utime(header)
-
-
-def prepare_pch(
-    build_dir: Path, include_headers: tuple[str, ...], extra: Iterable[str]
-) -> None:
-    """Compile ``build_dir``'s .gch from compile_commands.json flags and
-    write its ccache .sum.
-
-    The .sum doubles as the freshness stamp and folds in the compile
-    command, so a flag-only change rebuilds the .gch; ``extra`` carries
-    backend identity (framework version, sdkconfig, ...). A failed
-    compile falls back to the plain header include.
-    """
-    from esphome.core import CORE
-
-    header = build_dir / PCH_HEADER_NAME
-    gch = Path(f"{header}.gch")
-    sum_path = Path(f"{gch}.sum")
-    cmd_and_dir = pch_compile_command(build_dir, header, gch)
-    if cmd_and_dir is None:
-        # Freshness cannot be validated; a leftover .gch must not be consumed
-        discard_pch(build_dir)
-        return
-    cmd, cmd_dir = cmd_and_dir
-    # Strip like ccache's rewriting (user CCACHE_BASEDIR wins); the raw
-    # build path covers unresolved (symlinked) spellings
-    cmd_id = (
-        " ".join(cmd)
-        .replace(effective_ccache_basedir(), "")
-        .replace(str(CORE.build_path), "")
-    )
-    try:
-        checksum = pch_checksum(
-            CORE.relative_src_path(),
-            include_headers,
-            (
-                # The closure is sorted, so root order only enters via the text
-                pch_header_text(include_headers),
-                *extra,
-                cmd_id,
-            ),
-        )
-    except (OSError, UnicodeError) as err:
-        # Identity unknown: a stale cache entry must never be served
-        _LOGGER.warning(
-            "Could not establish the pch identity; compiling without it: %s", err
-        )
-        discard_pch(build_dir)
-        return
-    if gch.is_file() and _read_stamp(sum_path) == checksum:
-        _log_pch_in_use()
-        return
-    failed_marker = Path(f"{gch}.failed")
-    if _read_stamp(failed_marker) == checksum:
-        _LOGGER.info(
-            "Precompiled header disabled after an earlier failure; delete %s to retry",
-            failed_marker,
-        )
-        return
-    _log_pch_in_use()
-    try:
-        result = subprocess.run(
-            cmd,
-            cwd=cmd_dir,
-            # C locale keeps diagnostics matchable by _TRANSIENT_ERRORS
-            env={**os.environ, "LC_ALL": "C"},
-            capture_output=True,
-            text=True,
-            check=False,
-            timeout=300,
-        )
-        error = None
-        if result.returncode < 0:
-            # Killed by a signal (OOM, ^C): environmental, do not latch
-            _LOGGER.warning(
-                "Precompiled header compile was killed (signal %d); retrying "
-                "next build",
-                -result.returncode,
-            )
-            discard_pch(build_dir)
-            return
-        if result.returncode != 0:
-            error = result.stderr.strip() or f"exit code {result.returncode}"
-        elif not gch.is_file():
-            error = "compiler produced no .gch"
-    except (OSError, subprocess.SubprocessError) as err:
-        # Transient (timeout, spawn/IO): warn and retry next build, no marker
-        _LOGGER.warning("Precompiled header compile did not run: %s", err)
-        discard_pch(build_dir)
-        return
-    if error is not None:
-        _LOGGER.warning(
-            "Precompiled header failed; compiling without it: %s", error[:400]
-        )
-        # This path latches, so keep the full compiler output recoverable
-        _LOGGER.debug("Full pch compile output: %s", error)
-        discard_pch(build_dir)
-        if any(m in error for m in _TRANSIENT_ERRORS):
-            # Resource exhaustion clears on its own; retry next build
-            return
-        # Skip retries until a header/flag/backend-identity/command change
-        failed_marker.write_text(checksum + "\n", encoding="utf-8")
-        os.utime(header)
-        return
-    failed_marker.unlink(missing_ok=True)
-    sum_path.write_text(checksum + "\n", encoding="utf-8")
-    # Consumers depend on the header (depfiles cannot see through a .gch);
-    # bump it so users of the previous .gch recompile
-    os.utime(header)

esphome/components/api/api.proto

@@ -70,13 +70,17 @@ service APIConnection {
   rpc zwave_proxy_frame(ZWaveProxyFrame) returns (void) {}
   rpc zwave_proxy_request(ZWaveProxyRequest) returns (void) {}
 
+  rpc zigbee_proxy_request(ZigbeeProxyRequest) returns (void) {}
+
   rpc infrared_rf_transmit_raw_timings(InfraredRFTransmitRawTimingsRequest) returns (void) {}
 
   rpc serial_proxy_configure(SerialProxyConfigureRequest) returns (void) {}
   rpc serial_proxy_write(SerialProxyWriteRequest) returns (void) {}
   rpc serial_proxy_set_modem_pins(SerialProxySetModemPinsRequest) returns (void) {}
   rpc serial_proxy_get_modem_pins(SerialProxyGetModemPinsRequest) returns (void) {}
+  rpc serial_proxy_get_usb_info(SerialProxyGetUsbInfoRequest) returns (void) {}
   rpc serial_proxy_request(SerialProxyRequest) returns (void) {}
+  rpc serial_proxy_set_mode(SerialProxySetModeRequest) returns (void) {}
 }
 
 
@@ -227,6 +231,11 @@ enum SerialProxyPortType {
   SERIAL_PROXY_PORT_TYPE_TTL = 0;
   SERIAL_PROXY_PORT_TYPE_RS232 = 1;
   SERIAL_PROXY_PORT_TYPE_RS485 = 2;
+  // A serial device attached through a USB bridge. Set by the device configuration, never
+  // by the user; identifies ports whose USB identity can be read with
+  // SerialProxyGetUsbInfoRequest. Deliberately not a USB endpoint type: serial_proxy
+  // carries serial devices only, whatever bridge chip connects them.
+  SERIAL_PROXY_PORT_TYPE_USB_SERIAL = 3;
 }
 
 message SerialProxyInfo {
@@ -331,6 +340,10 @@ message DeviceInfoResponse {
   // all-zeros PSK, so the api encryption key can be provisioned without being
   // sent in plaintext (protects against passive sniffing, not active MITM)
   bool api_encryption_provisionable = 26 [(field_ifdef) = "USE_API_NOISE"];
+
+  // Indicates if Zigbee proxy support is available and features supported
+  uint32 zigbee_proxy_feature_flags = 27 [(field_ifdef) = "USE_ZIGBEE_PROXY"];
+  uint64 zigbee_ieee_address = 28 [(field_ifdef) = "USE_ZIGBEE_PROXY"];
 }
 
 // ==================== DEVICE CAPABILITIES ====================
@@ -2726,7 +2739,8 @@ enum SerialProxyParity {
   SERIAL_PROXY_PARITY_ODD = 2;
 }
 
-// Configure UART parameters for a serial proxy instance
+// Configure UART parameters for a serial proxy instance. Only the subscribed client may
+// configure the port; others are refused with PORT_IN_USE (since API 1.17).
 message SerialProxyConfigureRequest {
   option (id) = 138;
   option (source) = SOURCE_CLIENT;
@@ -2752,7 +2766,8 @@ message SerialProxyDataReceived {
   bytes data = 2;               // Raw data received from the serial device
 }
 
-// Write data to a serial device
+// Write data to a serial device. Only the subscribed client may write; writes from
+// others are ignored (since API 1.17).
 message SerialProxyWriteRequest {
   option (id) = 140;
   option (source) = SOURCE_CLIENT;
@@ -2763,7 +2778,8 @@ message SerialProxyWriteRequest {
   bytes data = 2;               // Raw data to write to the serial device
 }
 
-// Set modem control pin states (RTS and DTR)
+// Set modem control pin states (RTS and DTR). Only the subscribed client may set them;
+// others are refused with PORT_IN_USE (since API 1.17).
 message SerialProxySetModemPinsRequest {
   option (id) = 141;
   option (source) = SOURCE_CLIENT;
@@ -2802,6 +2818,7 @@ enum SerialProxyRequestType {
   // error the device answers with INVALID_ARGUMENT.
   SERIAL_PROXY_REQUEST_TYPE_CONFIGURE = 3;      // Acknowledges a SerialProxyConfigureRequest
   SERIAL_PROXY_REQUEST_TYPE_SET_MODEM_PINS = 4; // Acknowledges a SerialProxySetModemPinsRequest
+  SERIAL_PROXY_REQUEST_TYPE_SET_MODE = 5;       // Acknowledges a SerialProxySetModeRequest (since API 1.17)
 }
 
 enum SerialProxyStatus {
@@ -2814,7 +2831,8 @@ enum SerialProxyStatus {
   SERIAL_PROXY_STATUS_INVALID_ARGUMENT = 6; // Invalid instance index or parameter value
 }
 
-// Generic request message for simple serial proxy operations
+// Generic request message for simple serial proxy operations. FLUSH requires an active
+// subscription; it is refused with PORT_IN_USE otherwise (since API 1.17).
 message SerialProxyRequest {
   option (id) = 144;
   option (source) = SOURCE_CLIENT;
@@ -2838,6 +2856,59 @@ message SerialProxyRequestResponse {
   string error_message = 4;            // Additional detail on failure (optional)
 }
 
+// How a port treats the bytes passing through it. RAW is a plain byte pipe; PROTOCOL
+// activates the port's protocol-aware tap (if one is configured), letting it observe
+// traffic and inject protocol bytes such as acknowledgements. Which protocol the tap
+// speaks is a property of the device configuration, discoverable from the tap
+// component's own API surface. A client that is about to flash firmware selects RAW
+// first, which definitively disables that injection.
+enum SerialProxyMode {
+  SERIAL_PROXY_MODE_RAW = 0;
+  SERIAL_PROXY_MODE_PROTOCOL = 1;
+}
+
+// Only the subscribed client may change the mode; any other caller -- including one that
+// never subscribed -- is refused with PORT_IN_USE. PROTOCOL is refused with NOT_SUPPORTED
+// when the port has no protocol-aware tap configured.
+message SerialProxySetModeRequest {
+  option (id) = 152;
+  option (source) = SOURCE_CLIENT;
+  option (ifdef) = "USE_SERIAL_PROXY";
+
+  uint32 instance = 1;
+  SerialProxyMode mode = 2;
+}
+
+// Ask for the USB identity of the device behind a USB_SERIAL port. Read-only, so no
+// subscription is required -- a client typically uses this to decide which port to
+// subscribe to. Answered with NOT_SUPPORTED on ports that are not USB_SERIAL.
+message SerialProxyGetUsbInfoRequest {
+  option (id) = 153;
+  option (source) = SOURCE_CLIENT;
+  option (ifdef) = "USE_SERIAL_PROXY";
+
+  uint32 instance = 1;
+}
+
+// The USB identity of the device currently behind a port, read live from the cached
+// USB descriptors. Fields are zero/empty while no device is connected.
+message SerialProxyGetUsbInfoResponse {
+  option (id) = 154;
+  option (source) = SOURCE_SERVER;
+  option (ifdef) = "USE_SERIAL_PROXY";
+
+  uint32 instance = 1;
+  SerialProxyStatus status = 2;   // NOT_SUPPORTED when the port is not USB_SERIAL
+  bool connected = 3;             // True when a USB device is currently attached
+  uint32 vendor_id = 4;
+  uint32 product_id = 5;
+  uint32 bcd_device = 6;
+  uint32 interface_number = 7;    // Channel index on multi-port bridges
+  string manufacturer = 8;
+  string product = 9;
+  string serial_number = 10;
+}
+
 // ==================== BLUETOOTH CONNECTION PARAMS ====================
 message BluetoothSetConnectionParamsRequest {
   option (id) = 145;
@@ -2859,3 +2930,18 @@ message BluetoothSetConnectionParamsResponse {
   uint64 address = 1;
   int32 error = 2;
 }
+
+// ==================== ZIGBEE ====================
+
+enum ZigbeeProxyRequestType {
+  ZIGBEE_PROXY_REQUEST_TYPE_NETWORK_INFO = 0;
+}
+
+message ZigbeeProxyRequest {
+  option (id) = 155;
+  option (source) = SOURCE_BOTH;
+  option (ifdef) = "USE_ZIGBEE_PROXY";
+
+  ZigbeeProxyRequestType type = 1;
+  bytes data = 2;
+}

esphome/components/api/api_connection.cpp

@@ -48,6 +48,12 @@
 #ifdef USE_ZWAVE_PROXY
 #include "esphome/components/zwave_proxy/zwave_proxy.h"
 #endif
+#ifdef USE_ZIGBEE_PROXY
+#include "esphome/components/zigbee_proxy/zigbee_proxy.h"
+#endif
+#ifdef USE_SERIAL_PROXY_USB_INFO
+#include "esphome/components/usb_host/usb_host.h"
+#endif
 #ifdef USE_WATER_HEATER
 #include "esphome/components/water_heater/water_heater.h"
 #endif
@@ -1389,6 +1395,12 @@ void APIConnection::on_z_wave_proxy_request(const ZWaveProxyRequest &msg) {
 }
 #endif
 
+#ifdef USE_ZIGBEE_PROXY
+void APIConnection::on_zigbee_proxy_request(const ZigbeeProxyRequest &msg) {
+  zigbee_proxy::global_zigbee_proxy->zigbee_proxy_request(this, msg);
+}
+#endif
+
 #ifdef USE_ALARM_CONTROL_PANEL
 bool APIConnection::send_alarm_control_panel_state(alarm_control_panel::AlarmControlPanel *a_alarm_control_panel) {
   return this->send_message_smart_(a_alarm_control_panel, AlarmControlPanelStateResponse::MESSAGE_TYPE,
@@ -1642,6 +1654,27 @@ void APIConnection::on_serial_proxy_get_modem_pins_request(const SerialProxyGetM
   }
 }
 
+void APIConnection::on_serial_proxy_get_usb_info_request(const SerialProxyGetUsbInfoRequest &msg) {
+  auto &proxies = App.get_serial_proxies();
+  SerialProxyGetUsbInfoResponse resp{};
+  resp.instance = msg.instance;
+  if (msg.instance >= proxies.size()) {
+    ESP_LOGW(TAG, "Serial proxy instance %" PRIu32 " out of range", msg.instance);
+    resp.status = enums::SERIAL_PROXY_STATUS_INVALID_ARGUMENT;
+  } else {
+#ifdef USE_SERIAL_PROXY_USB_INFO
+    // The response's strings are views into this buffer, which outlives the send below
+    usb_host::UsbDeviceInfo info;
+    proxies[msg.instance]->get_usb_info(info, resp);
+#else
+    resp.status = enums::SERIAL_PROXY_STATUS_NOT_SUPPORTED;
+#endif
+  }
+  if (!this->send_message(resp)) {
+    API_LOG_MSG_DROPPED(TAG, "Serial proxy response");
+  }
+}
+
 void APIConnection::on_serial_proxy_request(const SerialProxyRequest &msg) {
   auto &proxies = App.get_serial_proxies();
   if (msg.instance >= proxies.size()) {
@@ -1661,6 +1694,7 @@ void APIConnection::on_serial_proxy_request(const SerialProxyRequest &msg) {
       break;
     case enums::SERIAL_PROXY_REQUEST_TYPE_CONFIGURE:
     case enums::SERIAL_PROXY_REQUEST_TYPE_SET_MODEM_PINS:
+    case enums::SERIAL_PROXY_REQUEST_TYPE_SET_MODE:
       // Response-only discriminators; never valid in a request
       ESP_LOGW(TAG, "Response-only serial proxy request type: %" PRIu32, static_cast<uint32_t>(msg.type));
       status = enums::SERIAL_PROXY_STATUS_INVALID_ARGUMENT;
@@ -1673,6 +1707,19 @@ void APIConnection::on_serial_proxy_request(const SerialProxyRequest &msg) {
   send_serial_proxy_ack(this, msg.instance, msg.type, status);
 }
 
+void APIConnection::on_serial_proxy_set_mode_request(const SerialProxySetModeRequest &msg) {
+  auto &proxies = App.get_serial_proxies();
+  if (msg.instance >= proxies.size()) {
+    ESP_LOGW(TAG, "Serial proxy instance %" PRIu32 " out of range", msg.instance);
+    send_serial_proxy_ack(this, msg.instance, enums::SERIAL_PROXY_REQUEST_TYPE_SET_MODE,
+                          enums::SERIAL_PROXY_STATUS_INVALID_ARGUMENT);
+    return;
+  }
+  serial_proxy::SerialProxyResult result = proxies[msg.instance]->set_mode_from_client(this, msg.mode);
+  send_serial_proxy_ack(this, msg.instance, enums::SERIAL_PROXY_REQUEST_TYPE_SET_MODE,
+                        serial_proxy_result_to_status(result));
+}
+
 void APIConnection::send_serial_proxy_data(const SerialProxyDataReceived &msg) {
   if (!this->send_message(msg)) {
     ESP_LOGV(TAG, "Serial proxy data dropped, TCP buffer full");
@@ -1784,6 +1831,11 @@ void APIConnection::complete_authentication_() {
     zwave_proxy::global_zwave_proxy->api_connection_authenticated(this);
   }
 #endif
+#ifdef USE_ZIGBEE_PROXY
+  if (zigbee_proxy::global_zigbee_proxy != nullptr) {
+    zigbee_proxy::global_zigbee_proxy->api_connection_authenticated(this);
+  }
+#endif
 }
 
 bool APIConnection::send_hello_response_(const HelloRequest &msg) {
@@ -1799,7 +1851,7 @@ bool APIConnection::send_hello_response_(const HelloRequest &msg) {
 
   HelloResponse resp;
   resp.api_version_major = 1;
-  resp.api_version_minor = 16;
+  resp.api_version_minor = 17;
   // Send only the version string - the client only logs this for debugging and doesn't use it otherwise
   resp.server_info = ESPHOME_VERSION_REF;
   resp.name = StringRef(App.get_name());
@@ -1936,6 +1988,10 @@ bool APIConnection::send_device_info_response_() {
     info.configured_line_states = proxy->get_configured_modem_pins();
   }
 #endif
+#ifdef USE_ZIGBEE_PROXY
+  resp.zigbee_proxy_feature_flags = zigbee_proxy::global_zigbee_proxy->get_feature_flags();
+  resp.zigbee_ieee_address = zigbee_proxy::global_zigbee_proxy->get_ieee_address();
+#endif
 #ifdef USE_API_NOISE
   resp.api_encryption_supported = true;
 #ifndef USE_API_NOISE_PSK_FROM_YAML

esphome/components/api/api_connection.h

@@ -223,6 +223,10 @@ class APIConnection final : public APIServerConnectionBase {
   void on_z_wave_proxy_request(const ZWaveProxyRequest &msg);
 #endif
 
+#ifdef USE_ZIGBEE_PROXY
+  void on_zigbee_proxy_request(const ZigbeeProxyRequest &msg);
+#endif
+
 #ifdef USE_ALARM_CONTROL_PANEL
   bool send_alarm_control_panel_state(alarm_control_panel::AlarmControlPanel *a_alarm_control_panel);
   void on_alarm_control_panel_command_request(const AlarmControlPanelCommandRequest &msg);
@@ -243,7 +247,9 @@ class APIConnection final : public APIServerConnectionBase {
   void on_serial_proxy_write_request(const SerialProxyWriteRequest &msg);
   void on_serial_proxy_set_modem_pins_request(const SerialProxySetModemPinsRequest &msg);
   void on_serial_proxy_get_modem_pins_request(const SerialProxyGetModemPinsRequest &msg);
+  void on_serial_proxy_get_usb_info_request(const SerialProxyGetUsbInfoRequest &msg);
   void on_serial_proxy_request(const SerialProxyRequest &msg);
+  void on_serial_proxy_set_mode_request(const SerialProxySetModeRequest &msg);
   void send_serial_proxy_data(const SerialProxyDataReceived &msg);
 #endif
 

esphome/components/api/api_pb2.cpp

@@ -175,6 +175,12 @@ uint8_t *DeviceInfoResponse::encode(ProtoWriteBuffer &buffer PROTO_ENCODE_DEBUG_
 #endif
 #ifdef USE_API_NOISE
   ProtoEncode::encode_bool(pos PROTO_ENCODE_DEBUG_ARG, 26, this->api_encryption_provisionable);
+#endif
+#ifdef USE_ZIGBEE_PROXY
+  ProtoEncode::encode_uint32(pos PROTO_ENCODE_DEBUG_ARG, 27, this->zigbee_proxy_feature_flags);
+#endif
+#ifdef USE_ZIGBEE_PROXY
+  ProtoEncode::encode_uint64(pos PROTO_ENCODE_DEBUG_ARG, 28, this->zigbee_ieee_address);
 #endif
   return pos;
 }
@@ -240,6 +246,12 @@ uint32_t DeviceInfoResponse::calculate_size() const {
 #endif
 #ifdef USE_API_NOISE
   size += ProtoSize::calc_bool(2, this->api_encryption_provisionable);
+#endif
+#ifdef USE_ZIGBEE_PROXY
+  size += ProtoSize::calc_uint32(2, this->zigbee_proxy_feature_flags);
+#endif
+#ifdef USE_ZIGBEE_PROXY
+  size += ProtoSize::calc_uint64(2, this->zigbee_ieee_address);
 #endif
   return size;
 }
@@ -4253,6 +4265,57 @@ uint32_t SerialProxyRequestResponse::calculate_size() const {
   size += ProtoSize::calc_length(1, this->error_message.size());
   return size;
 }
+bool SerialProxySetModeRequest::decode_varint(uint32_t field_id, proto_varint_value_t value) {
+  switch (field_id) {
+    case 1:
+      this->instance = value;
+      break;
+    case 2:
+      this->mode = static_cast<enums::SerialProxyMode>(value);
+      break;
+    default:
+      return false;
+  }
+  return true;
+}
+bool SerialProxyGetUsbInfoRequest::decode_varint(uint32_t field_id, proto_varint_value_t value) {
+  switch (field_id) {
+    case 1:
+      this->instance = value;
+      break;
+    default:
+      return false;
+  }
+  return true;
+}
+uint8_t *SerialProxyGetUsbInfoResponse::encode(ProtoWriteBuffer &buffer PROTO_ENCODE_DEBUG_PARAM) const {
+  uint8_t *__restrict__ pos = buffer.get_pos();
+  ProtoEncode::encode_uint32(pos PROTO_ENCODE_DEBUG_ARG, 1, this->instance);
+  ProtoEncode::encode_uint32(pos PROTO_ENCODE_DEBUG_ARG, 2, static_cast<uint32_t>(this->status));
+  ProtoEncode::encode_bool(pos PROTO_ENCODE_DEBUG_ARG, 3, this->connected);
+  ProtoEncode::encode_uint32(pos PROTO_ENCODE_DEBUG_ARG, 4, this->vendor_id);
+  ProtoEncode::encode_uint32(pos PROTO_ENCODE_DEBUG_ARG, 5, this->product_id);
+  ProtoEncode::encode_uint32(pos PROTO_ENCODE_DEBUG_ARG, 6, this->bcd_device);
+  ProtoEncode::encode_uint32(pos PROTO_ENCODE_DEBUG_ARG, 7, this->interface_number);
+  ProtoEncode::encode_string(pos PROTO_ENCODE_DEBUG_ARG, 8, this->manufacturer);
+  ProtoEncode::encode_string(pos PROTO_ENCODE_DEBUG_ARG, 9, this->product);
+  ProtoEncode::encode_string(pos PROTO_ENCODE_DEBUG_ARG, 10, this->serial_number);
+  return pos;
+}
+uint32_t SerialProxyGetUsbInfoResponse::calculate_size() const {
+  uint32_t size = 0;
+  size += ProtoSize::calc_uint32(1, this->instance);
+  size += this->status ? 2 : 0;
+  size += ProtoSize::calc_bool(1, this->connected);
+  size += ProtoSize::calc_uint32(1, this->vendor_id);
+  size += ProtoSize::calc_uint32(1, this->product_id);
+  size += ProtoSize::calc_uint32(1, this->bcd_device);
+  size += ProtoSize::calc_uint32(1, this->interface_number);
+  size += ProtoSize::calc_length(1, this->manufacturer.size());
+  size += ProtoSize::calc_length(1, this->product.size());
+  size += ProtoSize::calc_length(1, this->serial_number.size());
+  return size;
+}
 #endif
 #ifdef USE_BLUETOOTH_PROXY_CONNECTIONS
 bool BluetoothSetConnectionParamsRequest::decode_varint(uint32_t field_id, proto_varint_value_t value) {
@@ -4290,5 +4353,41 @@ uint32_t BluetoothSetConnectionParamsResponse::calculate_size() const {
   return size;
 }
 #endif
+#ifdef USE_ZIGBEE_PROXY
+bool ZigbeeProxyRequest::decode_varint(uint32_t field_id, proto_varint_value_t value) {
+  switch (field_id) {
+    case 1:
+      this->type = static_cast<enums::ZigbeeProxyRequestType>(value);
+      break;
+    default:
+      return false;
+  }
+  return true;
+}
+bool ZigbeeProxyRequest::decode_length(uint32_t field_id, ProtoLengthDelimited value) {
+  switch (field_id) {
+    case 2: {
+      this->data = value.data();
+      this->data_len = value.size();
+      break;
+    }
+    default:
+      return false;
+  }
+  return true;
+}
+uint8_t *ZigbeeProxyRequest::encode(ProtoWriteBuffer &buffer PROTO_ENCODE_DEBUG_PARAM) const {
+  uint8_t *__restrict__ pos = buffer.get_pos();
+  ProtoEncode::encode_uint32(pos PROTO_ENCODE_DEBUG_ARG, 1, static_cast<uint32_t>(this->type));
+  ProtoEncode::encode_bytes(pos PROTO_ENCODE_DEBUG_ARG, 2, this->data, this->data_len);
+  return pos;
+}
+uint32_t ZigbeeProxyRequest::calculate_size() const {
+  uint32_t size = 0;
+  size += this->type ? 2 : 0;
+  size += ProtoSize::calc_length(1, this->data_len);
+  return size;
+}
+#endif
 
 }  // namespace esphome::api

esphome/components/api/api_pb2.h

@@ -23,6 +23,7 @@ enum SerialProxyPortType : uint32_t {
   SERIAL_PROXY_PORT_TYPE_TTL = 0,
   SERIAL_PROXY_PORT_TYPE_RS232 = 1,
   SERIAL_PROXY_PORT_TYPE_RS485 = 2,
+  SERIAL_PROXY_PORT_TYPE_USB_SERIAL = 3,
 };
 enum EntityCategory : uint32_t {
   ENTITY_CATEGORY_NONE = 0,
@@ -356,6 +357,7 @@ enum SerialProxyRequestType : uint32_t {
   SERIAL_PROXY_REQUEST_TYPE_FLUSH = 2,
   SERIAL_PROXY_REQUEST_TYPE_CONFIGURE = 3,
   SERIAL_PROXY_REQUEST_TYPE_SET_MODEM_PINS = 4,
+  SERIAL_PROXY_REQUEST_TYPE_SET_MODE = 5,
 };
 enum SerialProxyStatus : uint32_t {
   SERIAL_PROXY_STATUS_OK = 0,
@@ -366,6 +368,15 @@ enum SerialProxyStatus : uint32_t {
   SERIAL_PROXY_STATUS_PORT_IN_USE = 5,
   SERIAL_PROXY_STATUS_INVALID_ARGUMENT = 6,
 };
+enum SerialProxyMode : uint32_t {
+  SERIAL_PROXY_MODE_RAW = 0,
+  SERIAL_PROXY_MODE_PROTOCOL = 1,
+};
+#endif
+#ifdef USE_ZIGBEE_PROXY
+enum ZigbeeProxyRequestType : uint32_t {
+  ZIGBEE_PROXY_REQUEST_TYPE_NETWORK_INFO = 0,
+};
 #endif
 
 }  // namespace enums
@@ -549,7 +560,7 @@ class SerialProxyInfo final : public ProtoMessage {
 class DeviceInfoResponse final : public ProtoMessage {
  public:
   static constexpr uint16_t MESSAGE_TYPE = 10;
-  static constexpr uint16_t ESTIMATED_SIZE = 312;
+  static constexpr uint16_t ESTIMATED_SIZE = 322;
 #ifdef HAS_PROTO_MESSAGE_DUMP
   const LogString *message_name() const override { return LOG_STR("device_info_response"); }
 #endif
@@ -607,6 +618,12 @@ class DeviceInfoResponse final : public ProtoMessage {
 #endif
 #ifdef USE_API_NOISE
   bool api_encryption_provisionable{false};
+#endif
+#ifdef USE_ZIGBEE_PROXY
+  uint32_t zigbee_proxy_feature_flags{0};
+#endif
+#ifdef USE_ZIGBEE_PROXY
+  uint64_t zigbee_ieee_address{0};
 #endif
   uint8_t *encode(ProtoWriteBuffer &buffer PROTO_ENCODE_DEBUG_PARAM) const;
   uint32_t calculate_size() const;
@@ -3403,6 +3420,62 @@ class SerialProxyRequestResponse final : public ProtoMessage {
 
  protected:
 };
+class SerialProxySetModeRequest final : public ProtoDecodableMessage {
+ public:
+  static constexpr uint16_t MESSAGE_TYPE = 152;
+  static constexpr uint8_t ESTIMATED_SIZE = 6;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const LogString *message_name() const override { return LOG_STR("serial_proxy_set_mode_request"); }
+#endif
+  uint32_t instance{0};
+  enums::SerialProxyMode mode{};
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *dump_to(DumpBuffer &out) const override;
+#endif
+
+ protected:
+  bool decode_varint(uint32_t field_id, proto_varint_value_t value) override;
+};
+class SerialProxyGetUsbInfoRequest final : public ProtoDecodableMessage {
+ public:
+  static constexpr uint16_t MESSAGE_TYPE = 153;
+  static constexpr uint8_t ESTIMATED_SIZE = 4;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const LogString *message_name() const override { return LOG_STR("serial_proxy_get_usb_info_request"); }
+#endif
+  uint32_t instance{0};
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *dump_to(DumpBuffer &out) const override;
+#endif
+
+ protected:
+  bool decode_varint(uint32_t field_id, proto_varint_value_t value) override;
+};
+class SerialProxyGetUsbInfoResponse final : public ProtoMessage {
+ public:
+  static constexpr uint16_t MESSAGE_TYPE = 154;
+  static constexpr uint8_t ESTIMATED_SIZE = 51;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const LogString *message_name() const override { return LOG_STR("serial_proxy_get_usb_info_response"); }
+#endif
+  uint32_t instance{0};
+  enums::SerialProxyStatus status{};
+  bool connected{false};
+  uint32_t vendor_id{0};
+  uint32_t product_id{0};
+  uint32_t bcd_device{0};
+  uint32_t interface_number{0};
+  StringRef manufacturer{};
+  StringRef product{};
+  StringRef serial_number{};
+  uint8_t *encode(ProtoWriteBuffer &buffer PROTO_ENCODE_DEBUG_PARAM) const;
+  uint32_t calculate_size() const;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *dump_to(DumpBuffer &out) const override;
+#endif
+
+ protected:
+};
 #endif
 #ifdef USE_BLUETOOTH_PROXY_CONNECTIONS
 class BluetoothSetConnectionParamsRequest final : public ProtoDecodableMessage {
@@ -3442,5 +3515,27 @@ class BluetoothSetConnectionParamsResponse final : public ProtoMessage {
  protected:
 };
 #endif
+#ifdef USE_ZIGBEE_PROXY
+class ZigbeeProxyRequest final : public ProtoDecodableMessage {
+ public:
+  static constexpr uint16_t MESSAGE_TYPE = 155;
+  static constexpr uint8_t ESTIMATED_SIZE = 21;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const LogString *message_name() const override { return LOG_STR("zigbee_proxy_request"); }
+#endif
+  enums::ZigbeeProxyRequestType type{};
+  const uint8_t *data{nullptr};
+  uint16_t data_len{0};
+  uint8_t *encode(ProtoWriteBuffer &buffer PROTO_ENCODE_DEBUG_PARAM) const;
+  uint32_t calculate_size() const;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *dump_to(DumpBuffer &out) const override;
+#endif
+
+ protected:
+  bool decode_length(uint32_t field_id, ProtoLengthDelimited value) override;
+  bool decode_varint(uint32_t field_id, proto_varint_value_t value) override;
+};
+#endif
 
 }  // namespace esphome::api

esphome/components/api/api_pb2_defines.h

@@ -3,10 +3,8 @@
 #pragma once
 
 #include "esphome/core/defines.h"
-#if defined(USE_BLUETOOTH_PROXY) || defined(USE_BLUETOOTH_PROXY_CONNECTIONS)
 #ifndef USE_API_VARINT64
 #define USE_API_VARINT64
 #endif
-#endif
 
 namespace esphome::api {}  // namespace esphome::api

esphome/components/api/api_pb2_dump.cpp

@@ -143,6 +143,8 @@ template<> const char *proto_enum_to_string<enums::SerialProxyPortType>(enums::S
       return ESPHOME_PSTR("SERIAL_PROXY_PORT_TYPE_RS232");
     case enums::SERIAL_PROXY_PORT_TYPE_RS485:
       return ESPHOME_PSTR("SERIAL_PROXY_PORT_TYPE_RS485");
+    case enums::SERIAL_PROXY_PORT_TYPE_USB_SERIAL:
+      return ESPHOME_PSTR("SERIAL_PROXY_PORT_TYPE_USB_SERIAL");
     default:
       return ESPHOME_PSTR("UNKNOWN");
   }
@@ -854,6 +856,8 @@ template<> const char *proto_enum_to_string<enums::SerialProxyRequestType>(enums
       return ESPHOME_PSTR("SERIAL_PROXY_REQUEST_TYPE_CONFIGURE");
     case enums::SERIAL_PROXY_REQUEST_TYPE_SET_MODEM_PINS:
       return ESPHOME_PSTR("SERIAL_PROXY_REQUEST_TYPE_SET_MODEM_PINS");
+    case enums::SERIAL_PROXY_REQUEST_TYPE_SET_MODE:
+      return ESPHOME_PSTR("SERIAL_PROXY_REQUEST_TYPE_SET_MODE");
     default:
       return ESPHOME_PSTR("UNKNOWN");
   }
@@ -878,6 +882,26 @@ template<> const char *proto_enum_to_string<enums::SerialProxyStatus>(enums::Ser
       return ESPHOME_PSTR("UNKNOWN");
   }
 }
+template<> const char *proto_enum_to_string<enums::SerialProxyMode>(enums::SerialProxyMode value) {
+  switch (value) {
+    case enums::SERIAL_PROXY_MODE_RAW:
+      return ESPHOME_PSTR("SERIAL_PROXY_MODE_RAW");
+    case enums::SERIAL_PROXY_MODE_PROTOCOL:
+      return ESPHOME_PSTR("SERIAL_PROXY_MODE_PROTOCOL");
+    default:
+      return ESPHOME_PSTR("UNKNOWN");
+  }
+}
+#endif
+#ifdef USE_ZIGBEE_PROXY
+template<> const char *proto_enum_to_string<enums::ZigbeeProxyRequestType>(enums::ZigbeeProxyRequestType value) {
+  switch (value) {
+    case enums::ZIGBEE_PROXY_REQUEST_TYPE_NETWORK_INFO:
+      return ESPHOME_PSTR("ZIGBEE_PROXY_REQUEST_TYPE_NETWORK_INFO");
+    default:
+      return ESPHOME_PSTR("UNKNOWN");
+  }
+}
 #endif
 
 const char *HelloRequest::dump_to(DumpBuffer &out) const {
@@ -1008,6 +1032,12 @@ const char *DeviceInfoResponse::dump_to(DumpBuffer &out) const {
 #endif
 #ifdef USE_API_NOISE
   dump_field(out, ESPHOME_PSTR("api_encryption_provisionable"), this->api_encryption_provisionable);
+#endif
+#ifdef USE_ZIGBEE_PROXY
+  dump_field(out, ESPHOME_PSTR("zigbee_proxy_feature_flags"), this->zigbee_proxy_feature_flags);
+#endif
+#ifdef USE_ZIGBEE_PROXY
+  dump_field(out, ESPHOME_PSTR("zigbee_ieee_address"), this->zigbee_ieee_address);
 #endif
   return out.c_str();
 }
@@ -2805,6 +2835,31 @@ const char *SerialProxyRequestResponse::dump_to(DumpBuffer &out) const {
   dump_field(out, ESPHOME_PSTR("error_message"), this->error_message);
   return out.c_str();
 }
+const char *SerialProxySetModeRequest::dump_to(DumpBuffer &out) const {
+  MessageDumpHelper helper(out, ESPHOME_PSTR("SerialProxySetModeRequest"));
+  dump_field(out, ESPHOME_PSTR("instance"), this->instance);
+  dump_field(out, ESPHOME_PSTR("mode"), static_cast<enums::SerialProxyMode>(this->mode));
+  return out.c_str();
+}
+const char *SerialProxyGetUsbInfoRequest::dump_to(DumpBuffer &out) const {
+  MessageDumpHelper helper(out, ESPHOME_PSTR("SerialProxyGetUsbInfoRequest"));
+  dump_field(out, ESPHOME_PSTR("instance"), this->instance);
+  return out.c_str();
+}
+const char *SerialProxyGetUsbInfoResponse::dump_to(DumpBuffer &out) const {
+  MessageDumpHelper helper(out, ESPHOME_PSTR("SerialProxyGetUsbInfoResponse"));
+  dump_field(out, ESPHOME_PSTR("instance"), this->instance);
+  dump_field(out, ESPHOME_PSTR("status"), static_cast<enums::SerialProxyStatus>(this->status));
+  dump_field(out, ESPHOME_PSTR("connected"), this->connected);
+  dump_field(out, ESPHOME_PSTR("vendor_id"), this->vendor_id);
+  dump_field(out, ESPHOME_PSTR("product_id"), this->product_id);
+  dump_field(out, ESPHOME_PSTR("bcd_device"), this->bcd_device);
+  dump_field(out, ESPHOME_PSTR("interface_number"), this->interface_number);
+  dump_field(out, ESPHOME_PSTR("manufacturer"), this->manufacturer);
+  dump_field(out, ESPHOME_PSTR("product"), this->product);
+  dump_field(out, ESPHOME_PSTR("serial_number"), this->serial_number);
+  return out.c_str();
+}
 #endif
 #ifdef USE_BLUETOOTH_PROXY_CONNECTIONS
 const char *BluetoothSetConnectionParamsRequest::dump_to(DumpBuffer &out) const {
@@ -2823,6 +2878,14 @@ const char *BluetoothSetConnectionParamsResponse::dump_to(DumpBuffer &out) const
   return out.c_str();
 }
 #endif
+#ifdef USE_ZIGBEE_PROXY
+const char *ZigbeeProxyRequest::dump_to(DumpBuffer &out) const {
+  MessageDumpHelper helper(out, ESPHOME_PSTR("ZigbeeProxyRequest"));
+  dump_field(out, ESPHOME_PSTR("type"), static_cast<enums::ZigbeeProxyRequestType>(this->type));
+  dump_bytes_field(out, ESPHOME_PSTR("data"), this->data, this->data_len);
+  return out.c_str();
+}
+#endif
 
 }  // namespace esphome::api
 

esphome/components/api/api_pb2_service.cpp

@@ -712,6 +712,39 @@ void APIConnection::read_message_(uint32_t msg_size, uint32_t msg_type, const ui
       this->on_device_capabilities_request();
       break;
     }
+#ifdef USE_SERIAL_PROXY
+    case SerialProxySetModeRequest::MESSAGE_TYPE: {
+      SerialProxySetModeRequest msg;
+      msg.decode(msg_data, msg_size);
+#ifdef HAS_PROTO_MESSAGE_DUMP
+      this->log_receive_message_(LOG_STR("on_serial_proxy_set_mode_request"), msg);
+#endif
+      this->on_serial_proxy_set_mode_request(msg);
+      break;
+    }
+#endif
+#ifdef USE_SERIAL_PROXY
+    case SerialProxyGetUsbInfoRequest::MESSAGE_TYPE: {
+      SerialProxyGetUsbInfoRequest msg;
+      msg.decode(msg_data, msg_size);
+#ifdef HAS_PROTO_MESSAGE_DUMP
+      this->log_receive_message_(LOG_STR("on_serial_proxy_get_usb_info_request"), msg);
+#endif
+      this->on_serial_proxy_get_usb_info_request(msg);
+      break;
+    }
+#endif
+#ifdef USE_ZIGBEE_PROXY
+    case ZigbeeProxyRequest::MESSAGE_TYPE: {
+      ZigbeeProxyRequest msg;
+      msg.decode(msg_data, msg_size);
+#ifdef HAS_PROTO_MESSAGE_DUMP
+      this->log_receive_message_(LOG_STR("on_zigbee_proxy_request"), msg);
+#endif
+      this->on_zigbee_proxy_request(msg);
+      break;
+    }
+#endif
     default:
       break;
   }

esphome/components/api/api_pb2_service.h

@@ -235,9 +235,20 @@ class APIServerConnectionBase {
   void on_serial_proxy_request(const SerialProxyRequest &value){};
 #endif
 
+#ifdef USE_SERIAL_PROXY
+  void on_serial_proxy_set_mode_request(const SerialProxySetModeRequest &value){};
+#endif
+#ifdef USE_SERIAL_PROXY
+  void on_serial_proxy_get_usb_info_request(const SerialProxyGetUsbInfoRequest &value){};
+#endif
+
 #ifdef USE_BLUETOOTH_PROXY_CONNECTIONS
   void on_bluetooth_set_connection_params_request(const BluetoothSetConnectionParamsRequest &value){};
 #endif
+
+#ifdef USE_ZIGBEE_PROXY
+  void on_zigbee_proxy_request(const ZigbeeProxyRequest &value){};
+#endif
 };
 
 }  // namespace esphome::api

esphome/components/api/api_server.cpp

@@ -404,6 +404,14 @@ void APIServer::on_zwave_proxy_request(const ZWaveProxyRequest &msg) {
 }
 #endif
 
+#ifdef USE_ZIGBEE_PROXY
+void APIServer::on_zigbee_proxy_request(const ZigbeeProxyRequest &msg) {
+  // Very infrequent and small - send to all clients rather than tracking a subscription
+  for (auto &c : this->active_clients())
+    c->send_message(msg);
+}
+#endif
+
 #if defined(USE_IR_RF) || defined(USE_RADIO_FREQUENCY)
 void APIServer::send_infrared_rf_receive_event([[maybe_unused]] uint32_t device_id, uint32_t key,
                                                const std::vector<int32_t> *timings) {

esphome/components/api/api_server.h

@@ -189,6 +189,9 @@ class APIServer final : public Component,
 #ifdef USE_ZWAVE_PROXY
   void on_zwave_proxy_request(const ZWaveProxyRequest &msg);
 #endif
+#ifdef USE_ZIGBEE_PROXY
+  void on_zigbee_proxy_request(const ZigbeeProxyRequest &msg);
+#endif
 #if defined(USE_IR_RF) || defined(USE_RADIO_FREQUENCY)
   void send_infrared_rf_receive_event(uint32_t device_id, uint32_t key, const std::vector<int32_t> *timings);
 #endif

esphome/components/esp8266/__init__.py

@@ -3,10 +3,8 @@ from pathlib import Path
 import platform
 import re
 import subprocess
-import time
 from typing import Any
 
-from esphome.build_helpers.pch import pch_extra_scripts
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome.const import (
@@ -16,7 +14,6 @@ from esphome.const import (
     CONF_FRAMEWORK,
     CONF_PLATFORM_VERSION,
     CONF_SOURCE,
-    CONF_TOOLCHAIN,
     CONF_VERSION,
     KEY_CORE,
     KEY_FRAMEWORK_VERSION,
@@ -24,7 +21,6 @@ from esphome.const import (
     KEY_TARGET_PLATFORM,
     PLATFORM_ESP8266,
     ThreadModel,
-    Toolchain,
 )
 from esphome.core import (
     CORE,
@@ -35,13 +31,12 @@ from esphome.core import (
 )
 from esphome.core.config import BOARD_MAX_LENGTH
 from esphome.helpers import IS_MACOS, copy_file_if_changed
-from esphome.platformio.toolchain import copy_ccache_script, copy_pch_script
+from esphome.platformio.toolchain import copy_ccache_script
 from esphome.storage_json import StorageJSON
 from esphome.types import ConfigType
 
-from .boards import BOARDS, ESP8266_BOARD_BUILD, board_ld_script
+from .boards import BOARDS, board_ld_script
 from .const import (
-    BUILD_FLASH_MODES,
     CONF_EARLY_PIN_INIT,
     CONF_ENABLE_SERIAL,
     CONF_ENABLE_SERIAL1,
@@ -49,7 +44,6 @@ from .const import (
     KEY_BOARD,
     KEY_ESP8266,
     KEY_PIN_INITIAL_STATES,
-    KEY_SCANF_FLOAT,
     KEY_SERIAL1_REQUIRED,
     KEY_SERIAL_REQUIRED,
     KEY_WAVEFORM_REQUIRED,
@@ -109,53 +103,6 @@ def set_core_data(config: ConfigType) -> ConfigType:
     return config
 
 
-_TOOLCHAINS = (Toolchain.PLATFORMIO, Toolchain.ARDUINO)
-_validate_toolchain = cv.toolchain_enum(_TOOLCHAINS)
-_resolve_toolchain = cv.resolve_toolchain("ESP8266", _TOOLCHAINS, Toolchain.PLATFORMIO)
-
-
-def _validate_native_toolchain(config: ConfigType) -> ConfigType:
-    """Constraints of the native (non-PlatformIO) Arduino toolchain."""
-    if not CORE.using_toolchain_arduino:
-        return config
-    from esphome.arduino8266.framework import MIN_FRAMEWORK_VERSION
-
-    conf = config[CONF_FRAMEWORK]
-    version = cv.Version.parse(conf[CONF_VERSION])
-    if version < MIN_FRAMEWORK_VERSION:
-        raise cv.Invalid(
-            "'toolchain: arduino' requires framework version "
-            f"{MIN_FRAMEWORK_VERSION} or newer"
-        )
-    # platform_version is a PlatformIO concept; drop it (as esp32's native
-    # toolchain does), warning when a custom pin is discarded. The floor
-    # above guarantees the schema-derived default is the ARDUINO_4 spec.
-    if (
-        conf.pop(CONF_PLATFORM_VERSION, _ARDUINO_4_PLATFORM_SPEC)
-        != _ARDUINO_4_PLATFORM_SPEC
-    ):
-        _LOGGER.warning(
-            "'platform_version' is ignored by 'toolchain: arduino'; the native "
-            "toolchain downloads the framework and compiler directly"
-        )
-    if conf[CONF_SOURCE] != _format_framework_arduino_version(version):
-        raise cv.Invalid(
-            "'toolchain: arduino' does not support a custom framework source; "
-            "use 'toolchain: platformio'"
-        )
-    # BOARDS is a subset of ESP8266_BOARD_BUILD today; the second clause is
-    # a drift guard for the independently regenerated tables
-    if (
-        config[CONF_BOARD] not in BOARDS
-        or config[CONF_BOARD] not in ESP8266_BOARD_BUILD
-    ):
-        raise cv.Invalid(
-            f"Board '{config[CONF_BOARD]}' is not supported by "
-            "'toolchain: arduino'; use 'toolchain: platformio'"
-        )
-    return config
-
-
 def get_download_types(storage_json: StorageJSON) -> list[dict[str, str]]:
     """Binary-download entries for a built ESP8266 firmware.
 
@@ -185,7 +132,7 @@ def _format_framework_arduino_version(ver: cv.Version) -> str:
     # a PIO platformio/framework-arduinoespressif8266 value
     # List of package versions: https://api.registry.platformio.org/v3/packages/platformio/tool/framework-arduinoespressif8266
     # Same encoding the native toolchain uses for its package download, so a
-    # custom-source check against this value cannot drift from what it fetches.
+    # version bump cannot drift between the two paths.
     from esphome.arduino8266.framework import framework_package_version
 
     try:
@@ -247,7 +194,7 @@ def _arduino_check_versions(value: ConfigType) -> ConfigType:
     platform_version = value.get(CONF_PLATFORM_VERSION)
     if platform_version is None:
         if version >= cv.Version(3, 1, 0):
-            platform_version = _ARDUINO_4_PLATFORM_SPEC
+            platform_version = _parse_platform_version(str(ARDUINO_4_PLATFORM_VERSION))
         else:
             platform_version = _parse_platform_version(str(ARDUINO_3_PLATFORM_VERSION))
     value[CONF_PLATFORM_VERSION] = platform_version
@@ -270,10 +217,6 @@ def _parse_platform_version(value: Any) -> str:
         return value
 
 
-# The platform_version derived for every core >= 3.1.0 config
-_ARDUINO_4_PLATFORM_SPEC = _parse_platform_version(str(ARDUINO_4_PLATFORM_VERSION))
-
-
 ARDUINO_FRAMEWORK_SCHEMA = cv.All(
     cv.Schema(
         {
@@ -290,6 +233,7 @@ ARDUINO_FRAMEWORK_SCHEMA = cv.All(
 )
 
 
+BUILD_FLASH_MODES = ["qio", "qout", "dio", "dout"]
 CONFIG_SCHEMA = cv.All(
     cv.Schema(
         {
@@ -306,30 +250,15 @@ CONFIG_SCHEMA = cv.All(
             cv.Optional(CONF_ENABLE_SERIAL1): cv.boolean,
             cv.Optional(CONF_ENABLE_FULL_PRINTF, default=False): cv.boolean,
             cv.Optional(CONF_ENABLE_SCANF_FLOAT): cv.boolean,
-            cv.Optional(
-                CONF_TOOLCHAIN, visibility=cv.Visibility.ADVANCED
-            ): _validate_toolchain,
         }
     ),
-    _resolve_toolchain,
-    _validate_native_toolchain,
+    # Until the native toolchain lands, PlatformIO is the only backend;
+    # reject a --toolchain this platform cannot serve yet.
+    cv.require_platformio_toolchain("ESP8266"),
     set_core_data,
 )
 
 
-def native_toolchain_module():
-    """The native build backend for the resolved toolchain, if any.
-
-    ``__main__`` dispatches from its own toolchain-keyed table; this helper
-    serves the component's internal callers.
-    """
-    if not CORE.using_toolchain_arduino:
-        return None
-    from esphome.arduino8266 import toolchain
-
-    return toolchain
-
-
 def check_rosetta() -> None:
     """Fail fast when the x86_64 ESP8266 toolchain cannot run on this Mac.
 
@@ -365,13 +294,12 @@ def _choose_ld_script(board: str) -> str:
 
 @coroutine_with_priority(CoroPriority.PLATFORM)
 async def to_code(config: ConfigType) -> None:
-    use_platformio = CORE.using_toolchain_platformio
     cg.add(esp8266_ns.setup_preferences())
 
-    if use_platformio:
-        cg.add_platformio_option("lib_ldf_mode", "off")
-        cg.add_platformio_option("lib_compat_mode", "strict")
-        cg.add_platformio_option("board", config[CONF_BOARD])
+    cg.add_platformio_option("lib_ldf_mode", "off")
+    cg.add_platformio_option("lib_compat_mode", "strict")
+
+    cg.add_platformio_option("board", config[CONF_BOARD])
     cg.add_build_flag("-DUSE_ESP8266")
     cg.set_cpp_standard("gnu++20")
     cg.add_define("ESPHOME_BOARD", config[CONF_BOARD])
@@ -387,33 +315,28 @@ async def to_code(config: ConfigType) -> None:
             "enabling scanf float support (~8KB flash)"
         )
 
-    # The native generator reads the same decision (KEY_SCANF_FLOAT)
-    CORE.data[KEY_ESP8266][KEY_SCANF_FLOAT] = bool(enable_scanf_float)
-    if use_platformio:
-        extra_scripts = [
-            "pre:ccache.py",
-            "pre:testing_mode.py",
-            "pre:exclude_updater.py",
-            "pre:exclude_waveform.py",
-            "pre:relocate_ratetable.py",
-        ]
-        if not enable_scanf_float:
-            extra_scripts.append("pre:remove_float_scanf.py")
-        extra_scripts.extend(pch_extra_scripts())
-        extra_scripts.append("post:post_build.py")
-        cg.add_platformio_option("extra_scripts", extra_scripts)
+    extra_scripts = [
+        "pre:ccache.py",
+        "pre:testing_mode.py",
+        "pre:exclude_updater.py",
+        "pre:exclude_waveform.py",
+        "pre:relocate_ratetable.py",
+    ]
+    if not enable_scanf_float:
+        extra_scripts.append("pre:remove_float_scanf.py")
+    extra_scripts.append("post:post_build.py")
+    cg.add_platformio_option("extra_scripts", extra_scripts)
 
     conf = config[CONF_FRAMEWORK]
+    cg.add_platformio_option("framework", "arduino")
     cg.add_build_flag("-DUSE_ARDUINO")
     cg.add_build_flag("-DUSE_ESP8266_FRAMEWORK_ARDUINO")
     cg.add_build_flag("-Wno-nonnull-compare")
-    if use_platformio:
-        cg.add_platformio_option("framework", "arduino")
-        cg.add_platformio_option("platform", conf[CONF_PLATFORM_VERSION])
-        cg.add_platformio_option(
-            "platform_packages",
-            [f"platformio/framework-arduinoespressif8266@{conf[CONF_SOURCE]}"],
-        )
+    cg.add_platformio_option("platform", conf[CONF_PLATFORM_VERSION])
+    cg.add_platformio_option(
+        "platform_packages",
+        [f"platformio/framework-arduinoespressif8266@{conf[CONF_SOURCE]}"],
+    )
 
     # Default for platformio is LWIP2_LOW_MEMORY with:
     #  - MSS=536
@@ -451,8 +374,7 @@ async def to_code(config: ConfigType) -> None:
     # Force-include inline std::__throw_* overrides so GCC dead-strips the unused
     # libstdc++ error message strings (e.g. "basic_string::_M_create") from DRAM.
     # See throw_stubs.h for details. Must be prepended before <string>, so this
-    # uses build_src_flags with -include. Unconditional: the native build
-    # generator reads the same option, keeping one source of truth.
+    # uses build_src_flags with -include.
     cg.add_platformio_option(
         "build_src_flags", "-include esphome/components/esp8266/throw_stubs.h"
     )
@@ -482,8 +404,6 @@ async def to_code(config: ConfigType) -> None:
     # implementation in the Arduino ESP8266 core.
     cg.add_build_flag("-Wl,--wrap=millis")
 
-    # Unconditional: the native build generator reads the same option,
-    # keeping one source of truth
     cg.add_platformio_option("board_build.flash_mode", config[CONF_BOARD_FLASH_MODE])
 
     ver: cv.Version = CORE.data[KEY_CORE][KEY_FRAMEWORK_VERSION]
@@ -492,7 +412,7 @@ async def to_code(config: ConfigType) -> None:
         cg.RawExpression(f"VERSION_CODE({ver.major}, {ver.minor}, {ver.patch})"),
     )
 
-    if use_platformio and config[CONF_BOARD] in BOARDS:
+    if config[CONF_BOARD] in BOARDS:
         cg.add_platformio_option(
             "board_build.ldscript", _choose_ld_script(config[CONF_BOARD])
         )
@@ -533,24 +453,8 @@ async def finalize_serial_config() -> None:
         cg.add_build_flag("-DNO_GLOBAL_SERIAL1")
 
 
-# Called by __main__.compile_program; returning False falls through to the
-# PlatformIO toolchain.
-def run_compile(args, config: ConfigType) -> bool:
-    # Positive check: the native backend only runs when explicitly resolved
-    toolchain = native_toolchain_module()
-    if toolchain is None:
-        return False
-    if toolchain.run_compile(config, CORE.verbose) != 0:
-        raise EsphomeError("ESP8266 native build failed")
-    return True
-
-
 # Called by writer.py
 def copy_files() -> None:
-    # Native builds skip the PlatformIO extra scripts; the build generator
-    # carries their logic
-    if CORE.using_toolchain_arduino:
-        return
     dir = Path(__file__).parent
     for script in (
         "post_build",
@@ -565,7 +469,6 @@ def copy_files() -> None:
             CORE.relative_build_path(f"{script}.py"),
         )
     copy_ccache_script()
-    copy_pch_script()
 
 
 # ESP logs stack trace decoder, based on https://github.com/me-no-dev/EspExceptionDecoder
@@ -608,75 +511,22 @@ ESP8266_EXCEPTION_CODES = {
 }
 
 
-_DECODE_WARNED_AT: dict[str, float] = {}
+def _decode_pc(config: ConfigType, addr: str) -> None:
+    from esphome.platformio import toolchain
 
-
-def _warn_decode_problem(key: str, message: str, *args) -> bool:
-    """Warn, deduplicated briefly so a burst of stack-dump addresses warns
-    once but a later dump warns again; returns whether it warned so the
-    caller can mark suppressed addresses individually."""
-    now = time.monotonic()
-    last = _DECODE_WARNED_AT.get(key)
-    if last is not None and now - last < 30:
-        return False
-    _DECODE_WARNED_AT[key] = now
-    _LOGGER.warning(message, *args)
-    return True
-
-
-def _decode_pc(config: ConfigType, addr: str, *, bulk: bool = False) -> None:
-    """Decode one crash address. ``bulk``: the caller is scanning every
-    8-hex stack word, most of which are not code addresses -- unmappable
-    ones log at debug so real frames are not buried."""
-    if (native_toolchain := native_toolchain_module()) is not None:
-        addr2line = native_toolchain.get_addr2line_path()
-        elf = native_toolchain.get_elf_path()
-        for path in (addr2line, elf):
-            if not path.is_file():
-                _warn_decode_problem(
-                    str(path), "Cannot decode crash addresses: %s missing", path
-                )
-                # The detailed warning names no address; mark named
-                # registers, but bulk stack words at debug (~150 per dump)
-                log = _LOGGER.debug if bulk else _LOGGER.warning
-                log("Not decoded %s (toolchain file missing)", addr)
-                return
-        addr2line, elf = str(addr2line), str(elf)
-    else:
-        from esphome.platformio import toolchain
-
-        idedata = toolchain.get_idedata(config)
-        if not idedata.addr2line_path or not idedata.firmware_elf_path:
-            _warn_decode_problem(
-                "no-addr2line",
-                "Cannot decode crash addresses: no addr2line or ELF in idedata",
-            )
-            log = _LOGGER.debug if bulk else _LOGGER.warning
-            log("Not decoded %s (no addr2line or ELF)", addr)
-            return
-        addr2line, elf = idedata.addr2line_path, idedata.firmware_elf_path
-    command = [addr2line, "-pfiaC", "-e", elf, addr]
+    idedata = toolchain.get_idedata(config)
+    if not idedata.addr2line_path or not idedata.firmware_elf_path:
+        _LOGGER.debug("decode_pc no addr2line")
+        return
+    command = [idedata.addr2line_path, "-pfiaC", "-e", idedata.firmware_elf_path, addr]
     try:
         translation = subprocess.check_output(command, close_fds=False).decode().strip()
-    except Exception as err:  # noqa: BLE001  # pylint: disable=broad-except
-        # Warn, not debug: a failing addr2line must be visible. The warning
-        # is rate-limited across a dump, so mark every undecoded address
-        # inline or the rest read as merely unmappable
-        if not _warn_decode_problem(
-            "addr2line-failed", "Could not decode crash address %s (%s)", addr, err
-        ):
-            # The detailed warning already named this address; mark only
-            # the rate-limited ones, and bulk stack words at debug
-            log = _LOGGER.debug if bulk else _LOGGER.warning
-            log("Not decoded %s (addr2line failed)", addr)
+    except Exception:  # noqa: BLE001  # pylint: disable=broad-except
         _LOGGER.debug("Caught exception for command %s", command, exc_info=1)
         return
 
     if "?? ??:0" in translation:
-        # A named register that fails to decode is confusing silence; a
-        # bulk stack word failing is the expected common case
-        log = _LOGGER.debug if bulk else _LOGGER.warning
-        log("Not decoded %s (address not in %s)", addr, elf)
+        # Nothing useful
         return
     translation = translation.replace(" at ??:?", "").replace(":?", "")
     _LOGGER.warning("Decoded %s", translation)
@@ -746,6 +596,6 @@ def process_stacktrace(config: ConfigType, line: str, backtrace_state: bool) ->
 
     if backtrace_state:
         for addr in re.finditer(STACKTRACE_ESP8266_BACKTRACE_PC_RE, line):
-            _decode_pc(config, addr.group(), bulk=True)
+            _decode_pc(config, addr.group())
 
     return backtrace_state

esphome/components/esp8266/const.py

@@ -16,6 +16,7 @@ KEY_WAVEFORM_REQUIRED = "waveform_required"
 KEY_SERIAL_REQUIRED = "serial_required"
 KEY_SERIAL1_REQUIRED = "serial1_required"
 # Set for the native (non-PlatformIO) toolchain's build generator
+KEY_FLASH_MODE = "flash_mode"
 KEY_SCANF_FLOAT = "scanf_float"
 # Per-board flash-layout override consumed by board_ld_script()
 KEY_LDSCRIPT = "ldscript"
@@ -72,6 +73,3 @@ def enable_serial1() -> None:
             enable_serial1()
     """
     CORE.data.setdefault(KEY_ESP8266, {})[KEY_SERIAL1_REQUIRED] = True
-
-
-BUILD_FLASH_MODES = ("qio", "qout", "dio", "dout")

esphome/components/serial_proxy/__init__.py

@@ -18,9 +18,10 @@ from esphome import pins
 import esphome.codegen as cg
 from esphome.components import uart
 import esphome.config_validation as cv
-from esphome.const import CONF_ID, CONF_NAME
+from esphome.const import CONF_ID, CONF_NAME, CONF_UART_ID
 from esphome.core import CORE, coroutine_with_priority
 from esphome.coroutine import CoroPriority
+import esphome.final_validate as fv
 from esphome.types import ConfigType
 
 CODEOWNERS = ["@kbx81"]
@@ -30,14 +31,18 @@ MULTI_CONF = True
 
 serial_proxy_ns = cg.esphome_ns.namespace("serial_proxy")
 SerialProxy = serial_proxy_ns.class_("SerialProxy", cg.Component, uart.UARTDevice)
+SerialProxyTap = serial_proxy_ns.class_("SerialProxyTap")
 
 api_enums_ns = cg.esphome_ns.namespace("api").namespace("enums")
 SerialProxyPortType = api_enums_ns.enum("SerialProxyPortType")
+# User-selectable electrical types. USB_SERIAL is deliberately absent: it is derived
+# from the uart_id pointing at a usb_uart channel, never set by the user.
 SERIAL_PROXY_PORT_TYPES = {
     "TTL": SerialProxyPortType.SERIAL_PROXY_PORT_TYPE_TTL,
     "RS232": SerialProxyPortType.SERIAL_PROXY_PORT_TYPE_RS232,
     "RS485": SerialProxyPortType.SERIAL_PROXY_PORT_TYPE_RS485,
 }
+PORT_TYPE_USB_SERIAL = SerialProxyPortType.SERIAL_PROXY_PORT_TYPE_USB_SERIAL
 
 CONF_DTR_PIN = "dtr_pin"
 CONF_PORT_TYPE = "port_type"
@@ -62,7 +67,7 @@ CONFIG_SCHEMA = (
         {
             cv.GenerateID(): cv.declare_id(SerialProxy),
             cv.Required(CONF_NAME): cv.string_strict,
-            cv.Required(CONF_PORT_TYPE): cv.enum(SERIAL_PROXY_PORT_TYPES, upper=True),
+            cv.Optional(CONF_PORT_TYPE): cv.enum(SERIAL_PROXY_PORT_TYPES, upper=True),
             cv.Optional(CONF_RTS_PIN): pins.gpio_output_pin_schema,
             cv.Optional(CONF_DTR_PIN): pins.gpio_output_pin_schema,
         }
@@ -72,6 +77,26 @@ CONFIG_SCHEMA = (
 )
 
 
+def _uses_usb_uart(config: ConfigType, full_config: ConfigType) -> bool:
+    from esphome.components.usb_uart import is_usb_uart_channel
+
+    return is_usb_uart_channel(config[CONF_UART_ID], full_config)
+
+
+def _final_validate(config: ConfigType) -> ConfigType:
+    if _uses_usb_uart(config, fv.full_config.get()):
+        if CONF_PORT_TYPE in config:
+            raise cv.Invalid(
+                f"{CONF_PORT_TYPE} is set automatically for USB serial ports"
+            )
+    elif CONF_PORT_TYPE not in config:
+        raise cv.Invalid(f"{CONF_PORT_TYPE} is required")
+    return config
+
+
+FINAL_VALIDATE_SCHEMA = _final_validate
+
+
 @coroutine_with_priority(CoroPriority.FINAL)
 async def _add_serial_proxy_count_define() -> None:
     """Emit the SERIAL_PROXY_COUNT define once with the final instance count."""
@@ -86,7 +111,13 @@ async def to_code(config: ConfigType) -> None:
     await uart.register_uart_device(var, config)
     cg.add(cg.App.register_serial_proxy(var))
     cg.add(var.set_name(config[CONF_NAME]))
-    cg.add(var.set_port_type(config[CONF_PORT_TYPE]))
+    if _uses_usb_uart(config, CORE.config):
+        cg.add(var.set_port_type(PORT_TYPE_USB_SERIAL))
+        channel = await cg.get_variable(config[CONF_UART_ID])
+        cg.add(var.set_usb_channel(channel))
+        cg.add_define("USE_SERIAL_PROXY_USB_INFO")
+    else:
+        cg.add(var.set_port_type(config[CONF_PORT_TYPE]))
     cg.add_define("USE_SERIAL_PROXY")
 
     # Track instance count for the FINAL priority define

esphome/components/serial_proxy/serial_proxy.cpp

@@ -12,6 +12,10 @@
 #include "esphome/components/api/api_server.h"
 #endif
 
+#ifdef USE_SERIAL_PROXY_USB_INFO
+#include "esphome/components/usb_uart/usb_uart.h"
+#endif
+
 namespace esphome::serial_proxy {
 
 static const char *const TAG = "serial_proxy";
@@ -29,26 +33,57 @@ void SerialProxy::setup() {
 #ifdef USE_API
   // instance_index_ is fixed at registration time; pre-set it so loop() only needs to update data
   this->outgoing_msg_.instance = this->instance_index_;
+#endif
+#ifdef USE_SERIAL_PROXY_TAP
+  // A tap sets itself up before this runs (its setup priority is higher), so it may
+  // already be waiting on the port -- a boot-time handshake with the device, say. Leaving
+  // the loop enabled is what lets that finish; without it the tap would stall until a
+  // client happened to subscribe.
+  if (this->tap_ != nullptr && this->tap_->tap_needs_port()) {
+    return;
+  }
 #endif
   // No subscriber at startup; disable loop until a client subscribes
   this->disable_loop();
 }
 
-void SerialProxy::loop() {
-#ifdef USE_API
-  // Safety check — loop should only run when subscribed, but guard against races
-  if (this->api_connection_ == nullptr) [[unlikely]] {
-    this->disable_loop();
+#ifdef USE_SERIAL_PROXY_TAP
+void SerialProxy::reset_mode_() {
+  // The mode belongs to a session, not to the port. Carrying a departed client's choice
+  // over to the next one would inject protocol bytes into a stream that never asked for
+  // them -- a firmware upload, or any client built before this request existed and so
+  // unable to turn it off. Guessing RAW is the safe direction: a client that wanted
+  // protocol handling and did not ask for it merely sends its own acknowledgements.
+  if (this->mode_ == api::enums::SERIAL_PROXY_MODE_RAW) {
     return;
   }
+  ESP_LOGD(TAG, "Session ended, returning serial proxy [%" PRIu32 "] to RAW mode", this->instance_index_);
+  this->mode_ = api::enums::SERIAL_PROXY_MODE_RAW;
+}
+#endif
 
+void SerialProxy::loop() {
+#ifdef USE_API
   // Detect subscriber disconnect
-  if (this->api_connection_->is_marked_for_removal() || !this->api_connection_->is_connection_setup() ||
-      !api_is_connected()) {
+  if (this->api_connection_ != nullptr && (this->api_connection_->is_marked_for_removal() ||
+                                           !this->api_connection_->is_connection_setup() || !api_is_connected())) {
     ESP_LOGW(TAG, "Subscriber disconnected");
     this->api_connection_ = nullptr;
+    this->reset_mode_();
+  }
+
+  // With no subscriber there is normally nothing to do, but a tap may still need the port
+  // read -- it does its protocol work precisely while nobody else is listening.
+  if (this->api_connection_ == nullptr) [[unlikely]] {
+#ifdef USE_SERIAL_PROXY_TAP
+    if (this->tap_ == nullptr || !this->tap_->tap_needs_port()) {
+      this->disable_loop();
+      return;
+    }
+#else
     this->disable_loop();
     return;
+#endif
   }
 
   // Read available data from UART and forward to subscribed client
@@ -69,11 +104,54 @@ void __attribute__((noinline)) SerialProxy::read_and_send_(size_t available) {
   if (!this->read_array(buffer, to_read))
     return;
 
+#ifdef USE_SERIAL_PROXY_TAP
+  // Before forwarding, so a tap that answers the device (an acknowledgement, say) is not
+  // waiting on the network round trip to a subscriber that may not even exist.
+  if (this->tap_observing_()) {
+    this->tap_->on_device_rx(buffer, to_read);
+  }
+#endif
+
+  if (this->api_connection_ == nullptr) {
+    return;
+  }
   this->outgoing_msg_.set_data(buffer, to_read);
   this->api_connection_->send_serial_proxy_data(this->outgoing_msg_);
 }
 #endif
 
+#ifdef USE_SERIAL_PROXY_TAP
+
+bool SerialProxy::tap_observing_() const {
+  if (this->tap_ == nullptr) {
+    return false;
+  }
+  // With no subscriber, a tap doing its own protocol work (the boot-time handshake with
+  // the device, say) is served regardless of mode -- nobody has chosen one yet. Once a
+  // subscriber holds the port, the mode alone decides, so RAW stays inert.
+  if (this->api_connection_ == nullptr && this->tap_->tap_needs_port()) {
+    return true;
+  }
+  // Otherwise the mode decides. RAW must be inert: a client that flips to RAW before
+  // flashing firmware is entitled to a byte pipe with nothing injecting protocol bytes
+  // into it, and "the tap turned out not to recognise the stream" is not good enough.
+  return this->mode_ == api::enums::SERIAL_PROXY_MODE_PROTOCOL;
+}
+
+void SerialProxy::tap_pump() {
+#ifdef USE_API
+  // Nothing would consume the bytes; leave them in the FIFO
+  if (!this->tap_observing_() && this->api_connection_ == nullptr) {
+    return;
+  }
+  const size_t available = this->available();
+  if (available > 0) {
+    this->read_and_send_(available);
+  }
+#endif
+}
+#endif
+
 void SerialProxy::dump_config() {
   ESP_LOGCONFIG(TAG,
                 "Serial Proxy [%" PRIu32 "]:\n"
@@ -82,9 +160,10 @@ void SerialProxy::dump_config() {
                 "  RTS Pin: %s\n"
                 "  DTR Pin: %s",
                 this->instance_index_, this->name_ != nullptr ? this->name_ : "",
-                this->port_type_ == api::enums::SERIAL_PROXY_PORT_TYPE_RS485   ? LOG_STR_LITERAL("RS485")
-                : this->port_type_ == api::enums::SERIAL_PROXY_PORT_TYPE_RS232 ? LOG_STR_LITERAL("RS232")
-                                                                               : LOG_STR_LITERAL("TTL"),
+                this->port_type_ == api::enums::SERIAL_PROXY_PORT_TYPE_RS485        ? LOG_STR_LITERAL("RS485")
+                : this->port_type_ == api::enums::SERIAL_PROXY_PORT_TYPE_RS232      ? LOG_STR_LITERAL("RS232")
+                : this->port_type_ == api::enums::SERIAL_PROXY_PORT_TYPE_USB_SERIAL ? LOG_STR_LITERAL("USB_SERIAL")
+                                                                                    : LOG_STR_LITERAL("TTL"),
                 this->rts_pin_ != nullptr ? LOG_STR_LITERAL("configured") : LOG_STR_LITERAL("not configured"),
                 this->dtr_pin_ != nullptr ? LOG_STR_LITERAL("configured") : LOG_STR_LITERAL("not configured"));
 }
@@ -92,8 +171,9 @@ void SerialProxy::dump_config() {
 SerialProxyResult SerialProxy::configure(api::APIConnection *api_connection, uint32_t baudrate, bool flow_control,
                                          uint8_t parity, uint8_t stop_bits, uint8_t data_size) {
 #ifdef USE_API
-  if (this->port_claimed_by_other_(api_connection)) {
-    ESP_LOGW(TAG, "Ignoring configure request from client without port access [%" PRIu32 "]", this->instance_index_);
+  if (!this->is_subscriber_(api_connection)) {
+    ESP_LOGW(TAG, "Ignoring configure request from client without port subscription [%" PRIu32 "]",
+             this->instance_index_);
     return SerialProxyResult::SERIAL_PROXY_RESULT_PORT_IN_USE;
   }
 #endif
@@ -159,24 +239,80 @@ SerialProxyResult SerialProxy::configure(api::APIConnection *api_connection, uin
   return SerialProxyResult::SERIAL_PROXY_RESULT_OK;
 }
 
+SerialProxyResult SerialProxy::set_mode_from_client(api::APIConnection *api_connection,
+                                                    api::enums::SerialProxyMode mode) {
+#ifdef USE_API
+  // Only the live subscriber may change the mode, so the mode cannot outlive a session
+  if (!this->is_subscriber_(api_connection)) {
+    ESP_LOGW(TAG, "Ignoring mode request from client without port subscription [%" PRIu32 "]", this->instance_index_);
+    return SerialProxyResult::SERIAL_PROXY_RESULT_PORT_IN_USE;
+  }
+#endif
+  // Values come from a remote client
+  if (mode != api::enums::SERIAL_PROXY_MODE_RAW && mode != api::enums::SERIAL_PROXY_MODE_PROTOCOL) {
+    ESP_LOGW(TAG, "Invalid mode: %" PRIu32, static_cast<uint32_t>(mode));
+    return SerialProxyResult::SERIAL_PROXY_RESULT_INVALID_ARGUMENT;
+  }
+  // PROTOCOL on a port with no tap would be a silent no-op; refuse so the client knows
+#ifdef USE_SERIAL_PROXY_TAP
+  const bool has_tap = this->tap_ != nullptr;
+#else
+  const bool has_tap = false;
+#endif
+  if (mode == api::enums::SERIAL_PROXY_MODE_PROTOCOL && !has_tap) {
+    ESP_LOGW(TAG, "No tap on serial proxy [%" PRIu32 "]; PROTOCOL mode unavailable", this->instance_index_);
+    return SerialProxyResult::SERIAL_PROXY_RESULT_NOT_SUPPORTED;
+  }
+  ESP_LOGD(TAG, "Serial proxy [%" PRIu32 "] mode set to %s", this->instance_index_,
+           mode == api::enums::SERIAL_PROXY_MODE_PROTOCOL ? LOG_STR_LITERAL("PROTOCOL") : LOG_STR_LITERAL("RAW"));
+#ifdef USE_SERIAL_PROXY_TAP
+  const bool leaving_protocol_mode =
+      this->mode_ != api::enums::SERIAL_PROXY_MODE_RAW && mode == api::enums::SERIAL_PROXY_MODE_RAW;
+  this->mode_ = mode;
+
+  // Only for an explicit client request, not for reset_mode_() at the end of a session:
+  // an ordinary disconnect says nothing about the device, whereas a client deliberately
+  // asking for raw bytes usually precedes changing what the device is.
+  if (leaving_protocol_mode && this->tap_ != nullptr) {
+    this->tap_->on_protocol_disabled();
+  }
+#endif
+  return SerialProxyResult::SERIAL_PROXY_RESULT_OK;
+}
+
 void SerialProxy::write_from_client(api::APIConnection *api_connection, const uint8_t *data, size_t len) {
 #ifdef USE_API
-  // Bytes from a client other than the live subscriber would interleave with the
-  // subscriber's traffic on the wire
-  if (this->port_claimed_by_other_(api_connection)) {
-    ESP_LOGW(TAG, "Ignoring write from client without port access [%" PRIu32 "]", this->instance_index_);
+  // Bytes from anyone but the live subscriber would interleave with the subscriber's
+  // traffic -- or with an active tap's -- on the wire
+  if (!this->is_subscriber_(api_connection)) {
+    if (this->api_connection_ != nullptr) {
+      ESP_LOGW(TAG, "Ignoring write from client that does not hold serial proxy [%" PRIu32 "]", this->instance_index_);
+    } else {
+      // A legacy client streaming writes without subscribing would flood WARN, one per
+      // request; writes are the only high-rate, unacknowledged operation, so keep this
+      // visible without drowning the log
+      ESP_LOGV(TAG, "Ignoring write from client without port subscription [%" PRIu32 "]", this->instance_index_);
+    }
     return;
   }
 #endif
   if (data == nullptr || len == 0)
     return;
   this->write_array(data, len);
+
+#ifdef USE_SERIAL_PROXY_TAP
+  // After the write, so the tap observes the same ordering the device does
+  if (this->tap_observing_()) {
+    this->tap_->on_client_tx(data, len);
+  }
+#endif
 }
 
 SerialProxyResult SerialProxy::set_modem_pins(api::APIConnection *api_connection, uint32_t line_states) {
 #ifdef USE_API
-  if (this->port_claimed_by_other_(api_connection)) {
-    ESP_LOGW(TAG, "Ignoring modem pin request from client without port access [%" PRIu32 "]", this->instance_index_);
+  if (!this->is_subscriber_(api_connection)) {
+    ESP_LOGW(TAG, "Ignoring modem pin request from client without port subscription [%" PRIu32 "]",
+             this->instance_index_);
     return SerialProxyResult::SERIAL_PROXY_RESULT_PORT_IN_USE;
   }
 #endif
@@ -202,6 +338,27 @@ SerialProxyResult SerialProxy::set_modem_pins(api::APIConnection *api_connection
   return SerialProxyResult::SERIAL_PROXY_RESULT_OK;
 }
 
+#if defined(USE_SERIAL_PROXY_USB_INFO) && defined(USE_API)
+void SerialProxy::get_usb_info(usb_host::UsbDeviceInfo &info, api::SerialProxyGetUsbInfoResponse &resp) const {
+  if (this->usb_channel_ == nullptr) {
+    resp.status = api::enums::SERIAL_PROXY_STATUS_NOT_SUPPORTED;
+    return;
+  }
+  resp.interface_number = this->usb_channel_->get_index();
+  if (!this->usb_channel_->get_parent()->get_device_info(info)) {
+    // No device attached right now; not an error
+    return;
+  }
+  resp.connected = true;
+  resp.vendor_id = info.vendor_id;
+  resp.product_id = info.product_id;
+  resp.bcd_device = info.bcd_device;
+  resp.manufacturer = StringRef(info.manufacturer);
+  resp.product = StringRef(info.product);
+  resp.serial_number = StringRef(info.serial_number);
+}
+#endif
+
 uint32_t SerialProxy::get_modem_pins() const {
   return (this->rts_state_ ? static_cast<uint32_t>(SERIAL_PROXY_LINE_STATE_FLAG_RTS) : 0u) |
          (this->dtr_state_ ? static_cast<uint32_t>(SERIAL_PROXY_LINE_STATE_FLAG_DTR) : 0u);
@@ -210,8 +367,8 @@ uint32_t SerialProxy::get_modem_pins() const {
 SerialProxyResult SerialProxy::flush_port(api::APIConnection *api_connection) {
 #ifdef USE_API
   // Flushing stalls the port, so it gets the same ownership check as writes
-  if (this->port_claimed_by_other_(api_connection)) {
-    ESP_LOGW(TAG, "Ignoring flush from client without port access [%" PRIu32 "]", this->instance_index_);
+  if (!this->is_subscriber_(api_connection)) {
+    ESP_LOGW(TAG, "Ignoring flush from client without port subscription [%" PRIu32 "]", this->instance_index_);
     return SerialProxyResult::SERIAL_PROXY_RESULT_PORT_IN_USE;
   }
 #endif
@@ -230,11 +387,6 @@ SerialProxyResult SerialProxy::flush_port(api::APIConnection *api_connection) {
 }
 
 #ifdef USE_API
-bool SerialProxy::port_claimed_by_other_(api::APIConnection *api_connection) const {
-  return this->api_connection_ != nullptr && this->api_connection_ != api_connection &&
-         this->api_connection_->is_connection_setup();
-}
-
 SerialProxyResult SerialProxy::serial_proxy_request(api::APIConnection *api_connection,
                                                     api::enums::SerialProxyRequestType type) {
   switch (type) {
@@ -252,6 +404,10 @@ SerialProxyResult SerialProxy::serial_proxy_request(api::APIConnection *api_conn
           return SerialProxyResult::SERIAL_PROXY_RESULT_PORT_IN_USE;
         }
         ESP_LOGW(TAG, "Previous subscriber disconnected; taking over subscription");
+        // End the dead client's session before starting the new one, so its mode
+        // cannot leak into a session that never asked for it
+        this->api_connection_ = nullptr;
+        this->reset_mode_();
       }
       this->api_connection_ = api_connection;
       this->enable_loop();
@@ -264,7 +420,15 @@ SerialProxyResult SerialProxy::serial_proxy_request(api::APIConnection *api_conn
         return SerialProxyResult::SERIAL_PROXY_RESULT_OK;
       }
       this->api_connection_ = nullptr;
+      this->reset_mode_();
+#ifdef USE_SERIAL_PROXY_TAP
+      // Keep the loop alive for a tap that still needs the port (mirrors loop())
+      if (this->tap_ == nullptr || !this->tap_->tap_needs_port()) {
+        this->disable_loop();
+      }
+#else
       this->disable_loop();
+#endif
       ESP_LOGV(TAG, "API connection unsubscribed from serial proxy [%" PRIu32 "]", this->instance_index_);
       return SerialProxyResult::SERIAL_PROXY_RESULT_OK;
     default:

esphome/components/serial_proxy/serial_proxy.h

@@ -20,12 +20,22 @@
 #include "esphome/components/api/api_pb2.h"
 #endif
 
+#ifdef USE_SERIAL_PROXY_USB_INFO
+namespace esphome::usb_uart {
+class USBUartChannel;
+}  // namespace esphome::usb_uart
+namespace esphome::usb_host {
+struct UsbDeviceInfo;
+}  // namespace esphome::usb_host
+#endif
+
 // Forward-declare types needed outside the USE_API guard.
 namespace esphome::api {
 class APIConnection;
 namespace enums {
 enum SerialProxyPortType : uint32_t;
 enum SerialProxyRequestType : uint32_t;
+enum SerialProxyMode : uint32_t;
 }  // namespace enums
 }  // namespace esphome::api
 
@@ -52,6 +62,36 @@ enum class SerialProxyResult : uint8_t {
 /// Maximum bytes to read from UART in a single loop iteration
 inline constexpr size_t SERIAL_PROXY_MAX_READ_SIZE = 256;
 
+#ifdef USE_SERIAL_PROXY_TAP
+/// Observes a port's traffic without owning it, and may inject bytes of its own.
+///
+/// This exists so protocol-aware behaviour can be layered onto a plain byte pipe without
+/// the pipe knowing anything about the protocol: the tap is compiled in only when some
+/// component asks for one, so a proxy carrying an RS485 meter pays nothing for it.
+///
+/// A tap is an observer, never a gatekeeper -- it cannot suppress or alter the bytes
+/// flowing in either direction, so a misbehaving tap cannot corrupt the stream.
+class SerialProxyTap {
+ public:
+  /// Bytes read from the device, before they are forwarded to any subscriber.
+  virtual void on_device_rx(const uint8_t *data, size_t len) = 0;
+
+  /// Bytes a subscriber sent towards the device, after they have been written.
+  virtual void on_client_tx(const uint8_t *data, size_t len) = 0;
+
+  /// True when the port must keep reading even with no subscriber attached, so a tap can
+  /// do its own protocol work while nobody is listening. Honoured only while no
+  /// subscriber holds the port; with one attached, the port mode alone decides.
+  virtual bool tap_needs_port() const = 0;
+
+  /// A client explicitly turned protocol handling off for this port. Distinct from the
+  /// automatic reset when a session ends: this one means a client intends to do something
+  /// else with the device -- reflash it, most likely -- so anything the tap believes about
+  /// it should be treated as suspect.
+  virtual void on_protocol_disabled() = 0;
+};
+#endif
+
 class SerialProxy final : public uart::UARTDevice, public Component {
  public:
   void setup() override;
@@ -77,6 +117,9 @@ class SerialProxy final : public uart::UARTDevice, public Component {
   /// Get the port type
   api::enums::SerialProxyPortType get_port_type() const { return this->port_type_; }
 
+  /// Handle a mode change requested by an API client
+  SerialProxyResult set_mode_from_client(api::APIConnection *api_connection, api::enums::SerialProxyMode mode);
+
   /// Configure UART parameters and apply them
   /// @param api_connection The API connection requesting the change
   /// @param baudrate Baud rate in bits per second
@@ -121,13 +164,78 @@ class SerialProxy final : public uart::UARTDevice, public Component {
   /// Set the DTR GPIO pin (from YAML configuration)
   void set_dtr_pin(GPIOPin *pin) { this->dtr_pin_ = pin; }
 
+#ifdef USE_SERIAL_PROXY_USB_INFO
+  /// Attach the USB UART channel behind this port (from code generation)
+  void set_usb_channel(usb_uart::USBUartChannel *channel) { this->usb_channel_ = channel; }
+
+#ifdef USE_API
+  /// Fill a USB info response for this port. The response's strings are views into
+  /// info, so info must outlive the send.
+  void get_usb_info(usb_host::UsbDeviceInfo &info, api::SerialProxyGetUsbInfoResponse &resp) const;
+#endif
+#endif
+
+#ifdef USE_SERIAL_PROXY_TAP
+  /// Attach a traffic observer. At most one, set once at setup time.
+  void set_tap(SerialProxyTap *tap) { this->tap_ = tap; }
+
+  /// Write bytes originating from the tap rather than from a client. Bypasses the
+  /// subscriber ownership check, but only while the tap is being served bytes -- so a
+  /// port in RAW mode with a subscriber attached stays inert. Returns false when the
+  /// bytes were dropped for that reason.
+  bool write_from_tap(const uint8_t *data, size_t len) {
+    if (!this->tap_observing_()) {
+      return false;
+    }
+    this->write_array(data, len);
+    return true;
+  }
+
+  /// Whether the tap is currently being served bytes. Can flip false with no callback
+  /// (a subscriber attaching in RAW mode, say), so a tap should check before starting
+  /// protocol work and when a reply seems overdue.
+  bool tap_is_observed() const { return this->tap_observing_(); }
+
+  /// Resume reading after a tap's needs change. loop() disables itself when there is
+  /// neither a subscriber nor a tap that wants the port, so a tap starting fresh work
+  /// must ask for it back. Must be called from the main loop.
+  void tap_request_port() { this->enable_loop(); }
+
+  /// Whether the underlying device is present. On a USB UART this tracks enumeration, so
+  /// a tap can notice the device being unplugged and plugged back in.
+  bool is_device_connected() const { return this->parent_->is_connected(); }
+
+  /// Run one read-and-dispatch cycle immediately. Lets a tap make progress before the
+  /// main loop is running -- during setup, for instance, while a component is still
+  /// blocking on can_proceed(). Must not be called from on_device_rx() or
+  /// on_client_tx(): each nested cycle costs a 256-byte stack frame.
+  void tap_pump();
+#endif
+
  protected:
 #ifdef USE_API
-  /// Read from UART and send to API client (slow path with 256-byte stack buffer)
+  /// Read from UART, hand the bytes to any tap, and forward them to a subscriber
+  /// (slow path with a 256-byte stack buffer)
   void read_and_send_(size_t available);
 
-  /// True when a live subscriber other than the given connection holds the port
-  bool port_claimed_by_other_(api::APIConnection *api_connection) const;
+  /// True when the given connection is the live subscriber. Every port operation
+  /// (write, configure, modem pins, flush, mode) requires this, so an unsubscribed
+  /// client can never share the wire with the subscriber or an active tap.
+  bool is_subscriber_(api::APIConnection *api_connection) const { return this->api_connection_ == api_connection; }
+#endif
+
+#ifdef USE_SERIAL_PROXY_TAP
+  /// Return the port to RAW when a subscriber goes away, so the mode never outlives it
+  void reset_mode_();
+#else
+  /// Without a tap, PROTOCOL is refused, so the mode is fixed at RAW and there is
+  /// nothing to reset
+  void reset_mode_() {}
+#endif
+
+#ifdef USE_SERIAL_PROXY_TAP
+  /// True when the tap should be shown the traffic passing through this port
+  bool tap_observing_() const;
 #endif
 
   /// Instance index for identifying this proxy in API messages
@@ -147,6 +255,11 @@ class SerialProxy final : public uart::UARTDevice, public Component {
   /// Port type
   api::enums::SerialProxyPortType port_type_{};
 
+#ifdef USE_SERIAL_PROXY_TAP
+  /// How the bytes passing through are treated; zero is SERIAL_PROXY_MODE_RAW
+  api::enums::SerialProxyMode mode_{};
+#endif
+
   /// Optional GPIO pins for modem control
   GPIOPin *rts_pin_{nullptr};
   GPIOPin *dtr_pin_{nullptr};
@@ -154,6 +267,15 @@ class SerialProxy final : public uart::UARTDevice, public Component {
   /// Current modem pin states
   bool rts_state_{false};
   bool dtr_state_{false};
+
+#ifdef USE_SERIAL_PROXY_TAP
+  SerialProxyTap *tap_{nullptr};
+#endif
+
+#ifdef USE_SERIAL_PROXY_USB_INFO
+  /// The USB UART channel behind this port; nullptr on non-USB ports
+  usb_uart::USBUartChannel *usb_channel_{nullptr};
+#endif
 };
 
 }  // namespace esphome::serial_proxy

esphome/components/usb_host/usb_host.h

@@ -117,6 +117,20 @@ struct UsbEvent {
 
 // callback function type.
 
+// USB string descriptors hold at most 126 characters; one more for the terminator
+static constexpr size_t DESC_STRING_BUF_SIZE = 128;
+
+/// Identity of a connected USB device, copied out of the descriptors the USB host
+/// stack caches for the lifetime of the connection
+struct UsbDeviceInfo {
+  uint16_t vendor_id;
+  uint16_t product_id;
+  uint16_t bcd_device;
+  char manufacturer[DESC_STRING_BUF_SIZE];
+  char product[DESC_STRING_BUF_SIZE];
+  char serial_number[DESC_STRING_BUF_SIZE];
+};
+
 enum ClientState {
   USB_CLIENT_INIT = 0,
   USB_CLIENT_OPEN,
@@ -144,6 +158,10 @@ class USBClient : public Component {
   bool control_transfer(uint8_t type, uint8_t request, uint16_t value, uint16_t index, const transfer_cb_t &callback,
                         const std::vector<uint8_t> &data = {});
 
+  /// Copy the connected device's identity out of the cached USB descriptors.
+  /// Returns false when no device is connected.
+  bool get_device_info(UsbDeviceInfo &info) const;
+
   // Lock-free event queue and pool for USB task to main loop communication
   // Must be public for access from static callbacks
   LockFreeQueue<UsbEvent, USB_EVENT_QUEUE_SIZE> event_queue;

esphome/components/usb_host/usb_host_client.cpp

@@ -143,10 +143,8 @@ static void usb_client_print_config_descriptor(const usb_config_desc_t *cfg_desc
   } while (next_desc != NULL);
 }
 #endif
-// USB string descriptors: bLength (uint8_t, max 255) includes the 2-byte header (bLength and bDescriptorType).
-// Character count = (bLength - 2) / 2, max 126 chars + null terminator.
-static constexpr size_t DESC_STRING_BUF_SIZE = 128;
-
+// bLength (uint8_t, max 255) includes the 2-byte header (bLength and bDescriptorType),
+// so character count = (bLength - 2) / 2.
 static const char *get_descriptor_string(const usb_str_desc_t *desc, std::span<char, DESC_STRING_BUF_SIZE> buffer) {
   if (desc == nullptr || desc->bLength < 2)
     return "(unspecified)";
@@ -162,6 +160,41 @@ static const char *get_descriptor_string(const usb_str_desc_t *desc, std::span<c
   return buffer.data();
 }
 
+// A missing descriptor copies as an empty string, unlike the "(unspecified)"
+// placeholder the logging helper above uses
+static void copy_descriptor_string(const usb_str_desc_t *desc, std::span<char, DESC_STRING_BUF_SIZE> buffer) {
+  buffer[0] = '\0';
+  if (desc == nullptr || desc->bLength < 2)
+    return;
+  int char_count = (desc->bLength - 2) / 2;
+  char *p = buffer.data();
+  char *end = p + buffer.size() - 1;
+  for (int i = 0; i != char_count && p < end; i++) {
+    auto c = desc->wData[i];
+    if (c < 0x100)
+      *p++ = static_cast<char>(c);
+  }
+  *p = '\0';
+}
+
+bool USBClient::get_device_info(UsbDeviceInfo &info) const {
+  if (this->state_ != USB_CLIENT_CONNECTED)
+    return false;
+  const usb_device_desc_t *desc;
+  if (usb_host_get_device_descriptor(this->device_handle_, &desc) != ESP_OK)
+    return false;
+  info.vendor_id = desc->idVendor;
+  info.product_id = desc->idProduct;
+  info.bcd_device = desc->bcdDevice;
+  usb_device_info_t dev_info;
+  if (usb_host_device_info(this->device_handle_, &dev_info) != ESP_OK)
+    return false;
+  copy_descriptor_string(dev_info.str_desc_manufacturer, info.manufacturer);
+  copy_descriptor_string(dev_info.str_desc_product, info.product);
+  copy_descriptor_string(dev_info.str_desc_serial_num, info.serial_number);
+  return true;
+}
+
 // CALLBACK CONTEXT: USB task (called from usb_host_client_handle_events in USB task)
 static void client_event_cb(const usb_host_client_event_msg_t *event_msg, void *ptr) {
   auto *client = static_cast<USBClient *>(ptr);

esphome/components/usb_uart/__init__.py

@@ -16,7 +16,7 @@ from esphome.const import (
     CONF_DUMMY_RECEIVER,
     CONF_ID,
 )
-from esphome.core import CORE
+from esphome.core import CORE, ID
 from esphome.cpp_types import Component
 from esphome.types import ConfigType
 
@@ -27,6 +27,16 @@ usb_uart_ns = cg.esphome_ns.namespace("usb_uart")
 USBUartComponent = usb_uart_ns.class_("USBUartComponent", Component)
 USBUartChannel = usb_uart_ns.class_("USBUartChannel", UARTComponent)
 
+
+def is_usb_uart_channel(uart_id: ID, full_config: ConfigType) -> bool:
+    """Return True if the given ID refers to a channel of a configured usb_uart device."""
+    return any(
+        channel[CONF_ID] == uart_id
+        for device in full_config.get("usb_uart") or []
+        for channel in device[CONF_CHANNELS]
+    )
+
+
 UARTParityOptions = usb_uart_ns.enum("UARTParityOptions")
 UART_PARITY_OPTIONS = {
     "NONE": UARTParityOptions.UART_CONFIG_PARITY_NONE,

esphome/components/usb_uart/usb_uart.h

@@ -164,6 +164,9 @@ class USBUartChannelBase : public uart::UARTComponent, public Parented<USBUartCo
   /// they arrive, eliminating one full main-loop-wakeup cycle of latency.
   void set_rx_callback(std::function<void()> cb) { this->rx_callback_ = std::move(cb); }
 
+  /// Channel index on the bridge (interface number on multi-port bridges)
+  uint8_t get_index() const { return this->index_; }
+
  protected:
   // Not directly instantiable; construct a concrete channel type instead.
   USBUartChannelBase(uint8_t index, uint16_t buffer_size) : input_buffer_(RingBuffer(buffer_size)), index_(index) {}

esphome/components/zigbee_proxy/__init__.py

@@ -0,0 +1,80 @@
+import esphome.codegen as cg
+from esphome.components import serial_proxy
+import esphome.config_validation as cv
+from esphome.const import CONF_BUFFER_SIZE, CONF_ID, CONF_POWER_SAVE_MODE, CONF_WIFI
+import esphome.final_validate as fv
+
+CODEOWNERS = ["@kbx81"]
+DEPENDENCIES = ["api", "serial_proxy"]
+
+CONF_INITIAL_TIMEOUT = "initial_timeout"
+CONF_MIN_TIMEOUT = "min_timeout"
+CONF_MAX_TIMEOUT = "max_timeout"
+CONF_SERIAL_PROXY_ID = "serial_proxy_id"
+
+# Default ACK timeout values for the boot-time metadata harvest
+_DEFAULT_INITIAL_TIMEOUT = 1600
+_DEFAULT_MIN_TIMEOUT = 400
+_DEFAULT_MAX_TIMEOUT = 3200
+
+zigbee_proxy_ns = cg.esphome_ns.namespace("zigbee_proxy")
+ZigbeeProxy = zigbee_proxy_ns.class_(
+    "ZigbeeProxy", cg.Component, serial_proxy.SerialProxyTap
+)
+
+
+def final_validate(config):
+    full_config = fv.full_config.get()
+    if (wifi_conf := full_config.get(CONF_WIFI)) and (
+        wifi_conf.get(CONF_POWER_SAVE_MODE, "").lower() != "none"
+    ):
+        raise cv.Invalid(
+            f"{CONF_WIFI} {CONF_POWER_SAVE_MODE} must be set to 'none' when using Zigbee proxy"
+        )
+    return config
+
+
+CONFIG_SCHEMA = cv.All(
+    cv.Schema(
+        {
+            cv.GenerateID(): cv.declare_id(ZigbeeProxy),
+            cv.Required(CONF_SERIAL_PROXY_ID): cv.use_id(serial_proxy.SerialProxy),
+            cv.Optional(CONF_BUFFER_SIZE): cv.SplitDefault(
+                cv.int_range(min=256, max=2048),
+                esp8266=512,
+                default=1024,
+            ),
+            cv.Optional(
+                CONF_INITIAL_TIMEOUT, default=_DEFAULT_INITIAL_TIMEOUT
+            ): cv.int_range(min=10, max=10000),
+            cv.Optional(CONF_MIN_TIMEOUT, default=_DEFAULT_MIN_TIMEOUT): cv.int_range(
+                min=10, max=5000
+            ),
+            cv.Optional(CONF_MAX_TIMEOUT, default=_DEFAULT_MAX_TIMEOUT): cv.int_range(
+                min=50, max=10000
+            ),
+        }
+    ).extend(cv.COMPONENT_SCHEMA),
+)
+
+FINAL_VALIDATE_SCHEMA = final_validate
+
+
+async def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    await cg.register_component(var, config)
+
+    sp = await cg.get_variable(config[CONF_SERIAL_PROXY_ID])
+    cg.add(var.set_serial_proxy(sp))
+
+    cg.add_define("USE_ZIGBEE_PROXY")
+    # Compiles the tap interface into serial_proxy; without it the port is a plain byte pipe
+    cg.add_define("USE_SERIAL_PROXY_TAP")
+
+    # Set buffer size via define for compile-time allocation
+    if CONF_BUFFER_SIZE in config:
+        cg.add_define("ZIGBEE_PROXY_BUFFER_SIZE", config[CONF_BUFFER_SIZE])
+
+    cg.add(var.set_initial_timeout(config[CONF_INITIAL_TIMEOUT]))
+    cg.add(var.set_min_timeout(config[CONF_MIN_TIMEOUT]))
+    cg.add(var.set_max_timeout(config[CONF_MAX_TIMEOUT]))

esphome/components/zigbee_proxy/ash_detector.cpp

@@ -0,0 +1,256 @@
+#include "ash_detector.h"
+
+#ifdef USE_ZIGBEE_PROXY
+
+namespace esphome::zigbee_proxy {
+
+// Control byte of an RSTACK, and the only ASH version byte that can follow it
+static constexpr uint8_t ASH_RSTACK_CONTROL = 0xC1;
+static constexpr uint8_t ASH_PROTOCOL_VERSION = 0x02;
+static constexpr size_t ASH_RSTACK_BODY_SIZE = 3;  // control, version, reset code
+static constexpr size_t ASH_CRC_SIZE = 2;
+// Smallest legal frame on the wire: a bare control byte plus its CRC
+static constexpr size_t ASH_MIN_FRAME_SIZE = 1 + ASH_CRC_SIZE;
+
+// The opening EZSP version command is a constant: control 0x00 (frmNum 0, ackNum 0)
+// followed by [seq=0][frameControl=0][frameId=0] randomized by 0x42 0x21 0xA8. Only the
+// requested version varies, as version ^ 0x54, so it can be recovered for free.
+static constexpr uint8_t EZSP_VERSION_CMD_PREFIX[] = {0x00, 0x42, 0x21, 0xA8};
+static constexpr size_t EZSP_VERSION_CMD_SIZE = 5;
+static constexpr uint8_t EZSP_VERSION_RANDOM_MASK = 0x54;
+
+// Consecutive frames we could not accept, with neither a good frame nor a retransmission
+// in between, before concluding the peer is no longer speaking ASH. A real ASH peer must
+// retransmit an unacknowledged frame, so the absence of one is the positive evidence
+// here -- garbage on the line is not, since noise proves nothing either way.
+static constexpr uint8_t MAX_UNCONFIRMED_REJECTS = 4;
+
+bool ash_reset_code_is_known(uint8_t code) {
+  switch (code) {
+    case 0x00:  // RESET_UNKNOWN
+    case 0x01:  // RESET_EXTERNAL
+    case 0x02:  // RESET_POWER_ON
+    case 0x03:  // RESET_WATCHDOG
+    case 0x06:  // RESET_ASSERT
+    case 0x09:  // RESET_BOOTLOADER
+    case 0x0B:  // RESET_SOFTWARE
+    case 0x51:  // ERROR_EXCEEDED_MAXIMUM_ACK_TIMEOUT_COUNT
+    case 0x80:  // ERROR_CHIP_SPECIFIC
+    case 0x81:  // RESET_CHIP_SPECIFIC
+      return true;
+    default:
+      return false;
+  }
+}
+
+void AshFrameScanner::begin_frame_() {
+  this->index_ = 0;
+  this->crc_ = ASH_CRC_INIT;
+  this->escaped_ = false;
+  this->poisoned_ = false;
+}
+
+void AshFrameScanner::reset() {
+  this->begin_frame_();
+  this->frame_length_ = 0;
+  this->discarding_ = false;
+}
+
+ScanResult AshFrameScanner::feed(uint8_t byte) {
+  if (byte == ASH_FLAG_BYTE) {
+    // Snapshot everything the verdict depends on: begin_frame_() clears all of it.
+    const bool discarding = this->discarding_;
+    const bool poisoned = this->poisoned_;
+    const bool escaped = this->escaped_;
+    const size_t index = this->index_;
+    const uint16_t crc = this->crc_;
+    // A FLAG always starts the next frame afresh, whatever preceded it
+    this->begin_frame_();
+    this->discarding_ = false;
+
+    if (discarding || index == 0) {
+      // Consecutive delimiters carry no frame at all, so there is nothing to judge
+      this->frame_length_ = 0;
+      return ScanResult::NONE;
+    }
+    // Running the CRC over the body *and* its trailing CRC bytes leaves zero when
+    // correct, so validity needs no second pass over the frame.
+    if (poisoned || escaped || index < ASH_MIN_FRAME_SIZE || crc != 0) {
+      this->frame_length_ = 0;
+      return ScanResult::INVALID;
+    }
+    this->frame_length_ = index - ASH_CRC_SIZE;
+    return ScanResult::FRAME;
+  }
+
+  if (this->discarding_) {
+    return ScanResult::NONE;
+  }
+
+  switch (byte) {
+    case ASH_CANCEL_BYTE:
+      // Everything received since the last FLAG is to be ignored
+      this->begin_frame_();
+      return ScanResult::NONE;
+
+    case ASH_SUBSTITUTE_BYTE:
+      // A low-level error was flagged; ignore everything up to the next FLAG
+      this->discarding_ = true;
+      return ScanResult::NONE;
+
+    case ASH_XON_BYTE:
+    case ASH_XOFF_BYTE:
+      // Transport flow control, not frame content: skip it without disturbing the frame
+      return ScanResult::NONE;
+
+    case ASH_ESCAPE_BYTE:
+      this->escaped_ = true;
+      return ScanResult::NONE;
+
+    default:
+      break;
+  }
+
+  uint8_t value = byte;
+  if (this->escaped_) {
+    this->escaped_ = false;
+    value = byte ^ ASH_XOR_BYTE;
+    // An escape must decode to a reserved byte; anything else is not ASH framing at all
+    if (!ash_is_reserved(value)) {
+      this->poisoned_ = true;
+      return ScanResult::NONE;
+    }
+  }
+
+  if (this->index_ >= sizeof(this->buffer_)) {
+    this->poisoned_ = true;
+    return ScanResult::NONE;
+  }
+
+  this->buffer_[this->index_++] = value;
+  this->crc_ = ash_crc16(&value, 1, this->crc_);
+  return ScanResult::NONE;
+}
+
+void AshDetector::reset() {
+  this->ncp_scanner_.reset();
+  this->host_scanner_.reset();
+  this->state_ = AshDetectState::IDLE;
+  this->rx_sequence_ = 0;
+  this->ack_owed_ = false;
+  this->data_frame_ready_ = false;
+  this->unconfirmed_rejects_ = 0;
+  this->negotiated_version_ = 0;
+}
+
+void AshDetector::from_ncp(uint8_t byte) {
+  this->data_frame_ready_ = false;
+  switch (this->ncp_scanner_.feed(byte)) {
+    case ScanResult::FRAME:
+      this->handle_ncp_frame_();
+      break;
+    case ScanResult::INVALID:
+      // A delimited chunk that is not a frame. While armed this may be a corrupted ASH
+      // frame, which the peer will retransmit, or a sign the peer stopped speaking ASH.
+      // reject_() distinguishes the two by whether a retransmission ever arrives.
+      this->reject_();
+      break;
+    case ScanResult::NONE:
+      break;
+  }
+}
+
+void AshDetector::handle_ncp_frame_() {
+  const uint8_t *body = this->ncp_scanner_.frame();
+  const size_t length = this->ncp_scanner_.length();
+  const uint8_t control = body[0];
+
+  // RSTACK is the only way into the handshake, and the only way back after a firmware
+  // swap: a Spinel or bootloader NCP never emits one, so those stay unarmed forever.
+  if (control == ASH_RSTACK_CONTROL) {
+    if (length == ASH_RSTACK_BODY_SIZE && body[1] == ASH_PROTOCOL_VERSION && ash_reset_code_is_known(body[2])) {
+      this->state_ = AshDetectState::SAW_RSTACK;
+      this->rx_sequence_ = 0;
+      this->ack_owed_ = false;
+      this->unconfirmed_rejects_ = 0;
+    }
+    return;
+  }
+
+  if (this->state_ != AshDetectState::ARMED) {
+    return;
+  }
+
+  if ((control & 0x80) != 0) {
+    return;  // ACK/NAK/RST/ERROR: nothing is owed for these
+  }
+
+  const uint8_t frame_num = (control >> 4) & ASH_MAX_SEQUENCE;
+  const bool re_tx = (control & 0x08) != 0;
+
+  if (frame_num != this->rx_sequence_) {
+    // A retransmission still proves the peer is speaking ASH even though we cannot use
+    // this copy, so it clears the suspicion without being acknowledged.
+    if (re_tx) {
+      this->unconfirmed_rejects_ = 0;
+    } else {
+      this->reject_();
+    }
+    return;
+  }
+
+  this->rx_sequence_ = (this->rx_sequence_ + 1) & ASH_MAX_SEQUENCE;
+  this->pending_ack_ = this->rx_sequence_;
+  this->ack_owed_ = true;
+  this->data_frame_ready_ = true;
+  this->unconfirmed_rejects_ = 0;
+}
+
+void AshDetector::reject_() {
+  if (this->state_ != AshDetectState::ARMED) {
+    return;
+  }
+  if (++this->unconfirmed_rejects_ >= MAX_UNCONFIRMED_REJECTS) {
+    this->state_ = AshDetectState::IDLE;
+    this->unconfirmed_rejects_ = 0;
+  }
+}
+
+void AshDetector::from_host(uint8_t byte) {
+  if (this->host_scanner_.feed(byte) != ScanResult::FRAME) {
+    return;
+  }
+
+  if (this->state_ != AshDetectState::SAW_RSTACK) {
+    return;
+  }
+
+  const uint8_t *body = this->host_scanner_.frame();
+  if (this->host_scanner_.length() != EZSP_VERSION_CMD_SIZE) {
+    return;
+  }
+  for (size_t i = 0; i < sizeof(EZSP_VERSION_CMD_PREFIX); i++) {
+    if (body[i] != EZSP_VERSION_CMD_PREFIX[i]) {
+      return;
+    }
+  }
+
+  this->negotiated_version_ = body[4] ^ EZSP_VERSION_RANDOM_MASK;
+  this->state_ = AshDetectState::ARMED;
+  this->rx_sequence_ = 0;
+  this->ack_owed_ = false;
+  this->unconfirmed_rejects_ = 0;
+}
+
+bool AshDetector::take_pending_ack(uint8_t &ack_num) {
+  if (!this->ack_owed_) {
+    return false;
+  }
+  this->ack_owed_ = false;
+  ack_num = this->pending_ack_;
+  return true;
+}
+
+}  // namespace esphome::zigbee_proxy
+
+#endif  // USE_ZIGBEE_PROXY

esphome/components/zigbee_proxy/ash_detector.h

@@ -0,0 +1,118 @@
+#pragma once
+
+#include "esphome/core/defines.h"
+#ifdef USE_ZIGBEE_PROXY
+
+#include "ash_protocol.h"
+
+#include <cstddef>
+#include <cstdint>
+
+namespace esphome::zigbee_proxy {
+
+// Decides when it is safe to acknowledge NCP frames on a client's behalf.
+//
+// The client suppresses its own ACKs, so nobody else will send them, and injecting ASH
+// bytes into a stream that is not ASH would corrupt it. Detection is therefore one-sided:
+// arm only on the session handshake, which is a fixed byte string, and never on frame
+// validity, which non-ASH traffic can satisfy by luck.
+//
+//   RSTACK  (NCP -> host)   c1 02 <reset_code> <crc> 7e
+//   version (host -> NCP)   00 42 21 a8 <version^0x54> <crc> 7e
+//
+// Requiring both, in that order, in opposite directions cannot be satisfied by a
+// unidirectional byte stream whatever it contains -- which is exactly the situation
+// during a firmware upload. Verified against real .gbl images and real Spinel traffic:
+// zero false arms, and neither pattern occurs even as a substring.
+//
+// Getting it wrong in the other direction is cheap: a frame we decline to acknowledge is
+// retransmitted by the NCP, so we see a clean copy and lose only the ack timeout. That
+// asymmetry is why this errs towards silence everywhere.
+
+enum class AshDetectState : uint8_t {
+  IDLE,        // Not ASH, or not yet proven to be
+  SAW_RSTACK,  // Handshake half-complete; watching for the version command
+  ARMED,       // Session confirmed; acknowledging on the client's behalf
+};
+
+enum class ScanResult : uint8_t {
+  NONE,     // Mid-frame, or a delimiter that carried nothing
+  FRAME,    // frame()/length() hold a complete body with a verified CRC
+  INVALID,  // A delimited chunk arrived but was not a well-formed ASH frame
+};
+
+// Reassembles one direction of the byte stream into unstuffed, CRC-checked frames.
+// Mirrors bellows' AshProtocol.data_received: FLAG ends a frame, CANCEL discards what
+// precedes it, SUBSTITUTE poisons everything up to the next FLAG, and XON/XOFF are
+// transport flow control removed without disturbing the frame around them.
+class AshFrameScanner {
+ public:
+  ScanResult feed(uint8_t byte);
+  void reset();
+
+  // Valid only until the next feed() call, which begins overwriting the buffer.
+  const uint8_t *frame() const { return this->buffer_; }
+  size_t length() const { return this->frame_length_; }
+
+ private:
+  void begin_frame_();
+
+  // Frames are bounded by the ASH maximum, so a stream carrying no delimiters cannot
+  // grow the buffer without limit; it just keeps failing.
+  uint8_t buffer_[MAX_ASH_FRAME_SIZE];
+  size_t index_{0};         // accumulation position for the frame being read
+  size_t frame_length_{0};  // body length of the last completed frame
+  uint16_t crc_{ASH_CRC_INIT};
+  bool escaped_{false};
+  bool discarding_{false};
+  bool poisoned_{false};
+};
+
+class AshDetector {
+ public:
+  void reset();
+
+  // Feed observed traffic. Neither call gates forwarding: the detector only watches.
+  void from_ncp(uint8_t byte);
+  void from_host(uint8_t byte);
+
+  bool armed() const { return this->state_ == AshDetectState::ARMED; }
+
+  // True only while the host direction can affect the state machine, i.e. while waiting
+  // for the version command. Lets the caller skip scanning that direction entirely the
+  // rest of the time -- it is the one carrying firmware uploads.
+  bool needs_host_scan() const { return this->state_ == AshDetectState::SAW_RSTACK; }
+
+  // An acknowledgement became owed after the last from_ncp() call. Clears the flag.
+  bool take_pending_ack(uint8_t &ack_num);
+
+  // The EZSP frame carried by the DATA frame just accepted, for metadata sniffing. The
+  // ASH control byte is skipped, so offset 0 is the EZSP sequence number. Still
+  // randomized, and valid only until the next from_ncp() call.
+  const uint8_t *last_ezsp_frame() const { return this->ncp_scanner_.frame() + 1; }
+  size_t last_ezsp_frame_length() const {
+    const size_t length = this->ncp_scanner_.length();
+    return length > 0 ? length - 1 : 0;
+  }
+
+  AshDetectState state() const { return this->state_; }
+  uint8_t negotiated_version() const { return this->negotiated_version_; }
+
+ protected:
+  void handle_ncp_frame_();
+  void reject_();
+
+  AshFrameScanner ncp_scanner_;
+  AshFrameScanner host_scanner_;
+  AshDetectState state_{AshDetectState::IDLE};
+  uint8_t rx_sequence_{0};
+  uint8_t pending_ack_{0};
+  bool ack_owed_{false};
+  bool data_frame_ready_{false};
+  uint8_t unconfirmed_rejects_{0};
+  uint8_t negotiated_version_{0};
+};
+
+}  // namespace esphome::zigbee_proxy
+
+#endif  // USE_ZIGBEE_PROXY

esphome/components/zigbee_proxy/ash_protocol.cpp

@@ -0,0 +1,444 @@
+#include "zigbee_proxy.h"
+
+#ifdef USE_ZIGBEE_PROXY
+
+#include "esphome/core/log.h"
+#include "esphome/core/helpers.h"
+
+namespace esphome::zigbee_proxy {
+
+static const char *const TAG = "zigbee_proxy";
+
+static constexpr size_t ASH_MAX_LOG_BYTES = 168;  // Cap verbose hex dumps (168 * 3 = 504 byte buffer)
+
+// CRC-CCITT lookup table for polynomial 0x1021 (x^16 + x^12 + x^5 + 1)
+static const uint16_t CRC_TABLE[256] = {
+    0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7, 0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD,
+    0xE1CE, 0xF1EF, 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6, 0x9339, 0x8318, 0xB37B, 0xA35A,
+    0xD3BD, 0xC39C, 0xF3FF, 0xE3DE, 0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485, 0xA56A, 0xB54B,
+    0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D, 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
+    0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC, 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861,
+    0x2802, 0x3823, 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B, 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96,
+    0x1A71, 0x0A50, 0x3A33, 0x2A12, 0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A, 0x6CA6, 0x7C87,
+    0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41, 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
+    0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70, 0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A,
+    0x9F59, 0x8F78, 0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F, 0x1080, 0x00A1, 0x30C2, 0x20E3,
+    0x5004, 0x4025, 0x7046, 0x6067, 0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E, 0x02B1, 0x1290,
+    0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256, 0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
+    0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, 0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E,
+    0xC71D, 0xD73C, 0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634, 0xD94C, 0xC96D, 0xF90E, 0xE92F,
+    0x99C8, 0x89E9, 0xB98A, 0xA9AB, 0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3, 0xCB7D, 0xDB5C,
+    0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A, 0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
+    0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9, 0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83,
+    0x1CE0, 0x0CC1, 0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8, 0x6E17, 0x7E36, 0x4E55, 0x5E74,
+    0x2E93, 0x3EB2, 0x0ED1, 0x1EF0};
+
+void ash_randomize(uint8_t *data, size_t length) {
+  uint8_t rand = 0x42;
+  for (size_t i = 0; i < length; i++) {
+    data[i] ^= rand;
+    rand = (rand & 0x01) ? static_cast<uint8_t>((rand >> 1) ^ 0xB8) : static_cast<uint8_t>(rand >> 1);
+  }
+}
+
+uint16_t ash_crc16(const uint8_t *data, size_t length, uint16_t init) {
+  uint16_t crc = init;
+  for (size_t i = 0; i < length; i++) {
+    crc = (crc << 8) ^ CRC_TABLE[(crc >> 8) ^ data[i]];
+  }
+  return crc;
+}
+
+uint16_t ZigbeeProxy::calculate_crc_(const uint8_t *data, size_t length, uint16_t init) {
+  return ash_crc16(data, length, init);
+}
+
+bool ZigbeeProxy::validate_frame_crc_() {
+  // CRC is calculated over control byte + data
+  // rx_buffer_[0] contains control byte, rx_buffer_[1..rx_buffer_index_-3] contains data
+  // rx_buffer_[rx_buffer_index_-2] and rx_buffer_[rx_buffer_index_-1] contain CRC
+  if (this->rx_buffer_index_ < 3) {
+    // Frame too short to contain CRC
+    return false;
+  }
+
+  // Calculate CRC over control + data (exclude CRC bytes)
+  uint16_t calculated = this->calculate_crc_(this->rx_buffer_.data(), this->rx_buffer_index_ - 2);
+
+  // Extract received CRC (big-endian)
+  uint16_t received = (static_cast<uint16_t>(this->rx_buffer_[this->rx_buffer_index_ - 2]) << 8) |
+                      this->rx_buffer_[this->rx_buffer_index_ - 1];
+
+  if (calculated != received) {
+    ESP_LOGW(TAG, "CRC validation failed: calculated=0x%04X, received=0x%04X", calculated, received);
+    return false;
+  }
+
+  return true;
+}
+
+bool ZigbeeProxy::handle_ack_num_(uint8_t ack_num) {
+  // ackNum means "I expect frame N next", i.e. everything up to N-1 arrived, so a
+  // pending frame numbered ack_num-1 has been acknowledged. Carried by DATA, ACK
+  // and NAK alike.
+  if (!this->tx_buffer_pending_ || ack_num != ((this->tx_pending_frame_num_ + 1) & ASH_MAX_SEQUENCE)) {
+    return false;
+  }
+
+  uint32_t rtt = millis() - this->ack_timer_start_;
+  this->update_adaptive_timeout_(rtt);
+  ESP_LOGV(TAG, "Frame %d acknowledged, RTT: %u ms", this->tx_pending_frame_num_, rtt);
+  this->clear_tx_buffer_();
+  return true;
+}
+
+void ZigbeeProxy::parse_control_byte_(uint8_t control) {
+  // Decode frame type based on bit patterns:
+  // DATA:  0xxxxxxx (bit 7 = 0)
+  // ACK:   10x0xxxx (bits 7-6 = 10, bit 5 = 0)
+  // NAK:   10x1xxxx (bits 7-6 = 10, bit 5 = 1)
+  // RST:   11000000 (0xC0)
+  // RSTACK: 11000001 (0xC1)
+  // ERROR: 11000010 (0xC2)
+
+  AshFrameType frame_type;
+  if ((control & 0x80) == 0) {
+    // Bit 7 = 0: DATA frame
+    frame_type = AshFrameType::DATA;
+  } else if ((control & 0xC0) == 0x80) {
+    // Bits 7-6 = 10: ACK or NAK
+    // ACK format: 100nrPPP (bit 5 = 0)
+    // NAK format: 101nrPPP (bit 5 = 1)
+    if ((control & 0x20) == 0) {
+      frame_type = AshFrameType::ACK;
+    } else {
+      frame_type = AshFrameType::NAK;
+    }
+  } else {
+    // Bits 7-6 = 11: control frames (RST, RSTACK, ERROR)
+    uint8_t control_bits = control & 0x07;
+    if (control_bits == 0x00) {
+      frame_type = AshFrameType::RST;
+    } else if (control_bits == 0x01) {
+      frame_type = AshFrameType::RSTACK;
+    } else if (control_bits == 0x02) {
+      frame_type = AshFrameType::ERROR;
+    } else {
+      ESP_LOGW(TAG, "Unknown control frame type: 0x%02X", control);
+      return;
+    }
+  }
+
+  // Extract sequence numbers from DATA frame format: 0ffrPPPP
+  // Bits 6-4 = frmNum, bit 3 = reTx, bits 2-0 = ackNum
+  uint8_t frame_num = (control >> 4) & 0x07;  // Bits 6-4
+  uint8_t ack_num = control & 0x07;           // Bits 2-0
+  bool retx = (control & 0x08) != 0;          // Bit 3 (for DATA frames)
+
+  ESP_LOGV(TAG, "Parsed control byte: type=%d, frmNum=%d, ackNum=%d, reTx=%d", static_cast<int>(frame_type), frame_num,
+           ack_num, retx);
+
+  // Handle frame based on type
+  switch (frame_type) {
+    case AshFrameType::DATA: {
+      // Process the piggybacked ACK first: ackNum is valid regardless of the DATA
+      // frame's own sequence ordering
+      if (this->handle_ack_num_(ack_num)) {
+        ESP_LOGV(TAG, "ACK received (piggybacked in DATA)");
+      }
+
+      // Check sequence number
+      if (frame_num != this->rx_sequence_) {
+        if (retx && frame_num == ((this->rx_sequence_ - 1) & ASH_MAX_SEQUENCE)) {
+          // Retransmission of a frame we already ACKed (our ACK was lost) - re-ACK and discard
+          ESP_LOGV(TAG, "Duplicate DATA frame %d, re-sending ACK", frame_num);
+          this->send_ack_frame_(this->rx_sequence_);
+        } else {
+          ESP_LOGW(TAG, "Out of sequence DATA frame: expected %d, got %d", this->rx_sequence_, frame_num);
+          this->send_nak_frame_(this->rx_sequence_);
+        }
+        return;
+      }
+
+      // Increment RX sequence and send ACK (ack_num = next expected frame)
+      this->increment_rx_sequence_();
+      this->send_ack_frame_(this->rx_sequence_);
+
+      // Extract payload (skip control byte, exclude CRC)
+      size_t payload_length = this->rx_buffer_index_ > 3 ? this->rx_buffer_index_ - 3 : 0;
+      const uint8_t *payload = this->rx_buffer_.data() + 1;
+
+      // This path only runs during the boot harvest, where this component is the ASH
+      // endpoint and consumes frames itself, so they must be derandomized. A subscribed
+      // client is served by the transparent relay instead, which never reaches here.
+      if (payload_length > 0) {
+        ash_randomize(this->rx_buffer_.data() + 1, payload_length);
+        this->handle_boot_data_frame_(payload, payload_length);
+      }
+      break;
+    }
+
+    case AshFrameType::ACK:
+      this->handle_ack_num_(ack_num);
+      break;
+
+    case AshFrameType::NAK:
+      // A NAK carries valid ACK information like any other frame: ackNum is the
+      // next frame the NCP expects, so everything before it did arrive. Honour
+      // that first -- retransmitting an already-acknowledged frame otherwise
+      // burns all ASH_MAX_RETRIES and drops the link. bellows applies the same
+      // ACK handling to DATA, ACK and NAK alike.
+      if (this->handle_ack_num_(ack_num)) {
+        ESP_LOGW(TAG, "NAK received for frame %d (already acknowledged, not retransmitting)", ack_num);
+        break;
+      }
+      ESP_LOGW(TAG, "NAK received for frame %d, retransmitting", ack_num);
+      if (this->tx_buffer_pending_) {
+        this->handle_retransmission_();
+      }
+      break;
+
+    case AshFrameType::RST: {
+      // An NCP never sends RST in normal operation; treat it as a reset indication
+      // and run the RSTACK handling to resynchronize state (nothing is transmitted here)
+      ESP_LOGW(TAG, "Received unexpected RST frame from NCP, resynchronizing");
+      uint8_t rstack_data[] = {0x02, 0x01, 0x00};  // Synthesized RSTACK payload
+      this->handle_rstack_frame_(rstack_data, sizeof(rstack_data));
+      break;
+    }
+
+    case AshFrameType::RSTACK:
+      this->handle_rstack_frame_(this->rx_buffer_.data() + 1, this->rx_buffer_index_ - 3);
+      break;
+
+    case AshFrameType::ERROR:
+      this->handle_error_frame_(this->rx_buffer_.data() + 1, this->rx_buffer_index_ - 3);
+      break;
+  }
+}
+
+bool ZigbeeProxy::parse_byte_(uint8_t byte) {
+  static constexpr uint8_t ASH_CAN_BYTE = 0x1A;
+  static constexpr uint8_t ASH_XON_BYTE = 0x11;
+  static constexpr uint8_t ASH_XOFF_BYTE = 0x13;
+
+  // Reserved bytes are only meaningful when they appear *bare* in the stream, so
+  // they must be filtered here, before unescaping, and never afterwards. A frame
+  // whose control or data byte happens to equal one of them arrives stuffed (0x11
+  // is sent as 7D 31), and unescaping yields the real value -- so filtering after
+  // unescaping silently eats a valid control byte, shifting the whole frame by one
+  // and failing CRC on every retransmission. This mirrors bellows, which strips
+  // flow control from the raw buffer and only then unstuffs.
+  if (!this->escape_next_byte_) {
+    if (byte == ASH_CAN_BYTE) {
+      // Cancel: discard any partial frame
+      this->rx_buffer_index_ = 0;
+      this->parsing_state_ = ParsingState::WAIT_FLAG_START;
+      return false;
+    }
+    if (byte == ASH_XON_BYTE || byte == ASH_XOFF_BYTE) {
+      // Flow control: not part of any frame, may appear anywhere
+      return false;
+    }
+  }
+
+  switch (this->parsing_state_) {
+    case ParsingState::WAIT_FLAG_START:
+      // Handle escape sequences - NCP may send escaped control byte at frame start
+      if (byte == ASH_ESCAPE_BYTE) {
+        this->escape_next_byte_ = true;
+        return false;
+      }
+
+      if (this->escape_next_byte_) {
+        byte ^= ASH_XOR_BYTE;
+        this->escape_next_byte_ = false;
+      }
+
+      if (byte == ASH_FLAG_BYTE) {
+        // Start of frame with FLAG delimiter
+        this->rx_buffer_index_ = 0;
+        this->escape_next_byte_ = false;
+        this->parsing_state_ = ParsingState::WAIT_CONTROL;
+        ESP_LOGV(TAG, "Frame start detected (FLAG)");
+      } else if (this->ash_state_ == AshState::CONNECTED) {
+        // When connected, NCP often omits leading FLAG on responses
+        // Any byte could be a control byte:
+        //   - DATA frames: 0x00-0x7F (bit 7 = 0)
+        //   - ACK frames:  0x80-0x9F (bits 7-6 = 10, bit 5 = 0)
+        //   - NAK frames:  0xA0-0xBF (bits 7-6 = 10, bit 5 = 1)
+        //   - RST/RSTACK/ERROR: 0xC0-0xC2 (bits 7-6 = 11)
+        // Bare flow-control bytes were already filtered above, so anything
+        // reaching here is genuine frame content.
+        this->rx_buffer_index_ = 0;
+        this->rx_buffer_[this->rx_buffer_index_++] = byte;
+        this->parsing_state_ = ParsingState::WAIT_DATA;
+        ESP_LOGV(TAG, "Frame start detected (control byte 0x%02X)", byte);
+      } else if ((byte & 0x80) != 0) {
+        // Before connected, only accept control/management frames (bit 7 set)
+        // This handles RSTACK (0xC1), ACK (0x8X), NAK (0xAX), ERROR (0xC2)
+        this->rx_buffer_index_ = 0;
+        this->rx_buffer_[this->rx_buffer_index_++] = byte;
+        this->parsing_state_ = ParsingState::WAIT_DATA;
+        ESP_LOGV(TAG, "Frame start detected (control byte 0x%02X)", byte);
+      }
+      break;
+
+    case ParsingState::WAIT_CONTROL:
+      if (byte == ASH_FLAG_BYTE) {
+        // Empty frame or repeated FLAG
+        ESP_LOGV(TAG, "Empty frame or repeated FLAG, restarting");
+        this->rx_buffer_index_ = 0;
+        return false;
+      }
+
+      if (byte == ASH_ESCAPE_BYTE) {
+        this->escape_next_byte_ = true;
+        return false;
+      }
+
+      if (this->escape_next_byte_) {
+        byte ^= ASH_XOR_BYTE;
+        this->escape_next_byte_ = false;
+      }
+
+      // Store control byte
+      this->rx_buffer_[this->rx_buffer_index_++] = byte;
+      this->parsing_state_ = ParsingState::WAIT_DATA;
+      break;
+
+    case ParsingState::WAIT_DATA:
+      if (byte == ASH_FLAG_BYTE) {
+        // End of frame - validate and process
+        ESP_LOGV(TAG, "Frame complete, %u bytes in buffer", this->rx_buffer_index_);
+        if (this->validate_frame_crc_()) {
+          this->parse_control_byte_(this->rx_buffer_[0]);
+        } else {
+          // CRC failed - WARN logs byte count only; hex dump at VERBOSE (truncated to ASH_MAX_LOG_BYTES)
+          ESP_LOGW(TAG, "CRC failed (%u bytes)", this->rx_buffer_index_);
+#if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERBOSE
+          char hex_buf[format_hex_pretty_size(ASH_MAX_LOG_BYTES)];
+#endif
+          ESP_LOGV(TAG, "CRC failed frame: %s",
+                   format_hex_pretty_to(hex_buf, this->rx_buffer_.data(), this->rx_buffer_index_));
+          this->send_nak_frame_(this->rx_sequence_);
+        }
+        this->parsing_state_ = ParsingState::WAIT_FLAG_START;
+        return true;
+      }
+
+      if (byte == ASH_ESCAPE_BYTE) {
+        this->escape_next_byte_ = true;
+        return false;
+      }
+
+      if (this->escape_next_byte_) {
+        byte ^= ASH_XOR_BYTE;
+        this->escape_next_byte_ = false;
+      }
+
+      // Check buffer overflow
+      if (this->rx_buffer_index_ >= MAX_ASH_FRAME_SIZE) {
+        ESP_LOGE(TAG, "RX buffer overflow, frame too large");
+        this->parsing_state_ = ParsingState::WAIT_FLAG_START;
+        return false;
+      }
+
+      // Store data byte
+      this->rx_buffer_[this->rx_buffer_index_++] = byte;
+      break;
+
+    default:
+      this->parsing_state_ = ParsingState::WAIT_FLAG_START;
+      break;
+  }
+
+  return false;
+}
+
+// Appends a byte with ASH stuffing (reserved: FLAG, ESCAPE, XON, XOFF, SUB, CAN);
+// returns false if it would exceed capacity
+static bool append_byte_stuffed(uint8_t *output, size_t capacity, size_t &pos, uint8_t byte) {
+  const bool reserved = byte == ASH_FLAG_BYTE || byte == ASH_ESCAPE_BYTE || byte == 0x11 || byte == 0x13 ||
+                        byte == ASH_SUBSTITUTE_BYTE || byte == 0x1A;
+  if (pos + (reserved ? 2 : 1) > capacity) {
+    return false;
+  }
+  if (reserved) {
+    output[pos++] = ASH_ESCAPE_BYTE;
+    output[pos++] = byte ^ ASH_XOR_BYTE;
+  } else {
+    output[pos++] = byte;
+  }
+  return true;
+}
+
+size_t ZigbeeProxy::build_frame_(uint8_t *output, size_t capacity, const uint8_t *data, size_t length,
+                                 AshFrameType type, uint8_t frame_num, uint8_t ack_num, bool retx) {
+  size_t pos = 0;
+
+  // Start with FLAG
+  if (capacity < 1) {
+    return 0;
+  }
+  output[pos++] = ASH_FLAG_BYTE;
+
+  // Build control byte
+  uint8_t control = 0;
+  switch (type) {
+    case AshFrameType::DATA:
+      // DATA frame format: 0ffrPPPP
+      // Bit 7 = 0 (DATA indicator), bits 6-4 = frmNum, bit 3 = reTx, bits 2-0 = ackNum
+      control = (frame_num << 4) | (retx ? 0x08 : 0x00) | ack_num;
+      break;
+    case AshFrameType::ACK:
+      control = 0x80 | ack_num;
+      break;
+    case AshFrameType::NAK:
+      control = 0xA0 | ack_num;
+      break;
+    case AshFrameType::RST:
+      control = 0xC0;
+      break;
+    case AshFrameType::RSTACK:
+      control = 0xC1;
+      break;
+    case AshFrameType::ERROR:
+      control = 0xC2;
+      break;
+  }
+
+  // Add control byte with stuffing
+  if (!append_byte_stuffed(output, capacity, pos, control)) {
+    ESP_LOGE(TAG, "Frame too large for buffer (%u byte payload, %u byte buffer)", length, capacity);
+    return 0;
+  }
+
+  // Add data payload with stuffing
+  for (size_t i = 0; i < length; i++) {
+    if (!append_byte_stuffed(output, capacity, pos, data[i])) {
+      ESP_LOGE(TAG, "Frame too large for buffer (%u byte payload, %u byte buffer)", length, capacity);
+      return 0;
+    }
+  }
+
+  // Calculate CRC incrementally over control byte then data (avoids a MAX_ASH_FRAME_SIZE stack copy)
+  uint16_t crc = this->calculate_crc_(&control, 1);
+  if (length > 0) {
+    crc = this->calculate_crc_(data, length, crc);
+  }
+
+  // Add CRC with stuffing (big-endian), then the end FLAG
+  if (!append_byte_stuffed(output, capacity, pos, (crc >> 8) & 0xFF) ||
+      !append_byte_stuffed(output, capacity, pos, crc & 0xFF) || pos + 1 > capacity) {
+    ESP_LOGE(TAG, "Frame too large for buffer (%u byte payload, %u byte buffer)", length, capacity);
+    return 0;
+  }
+  output[pos++] = ASH_FLAG_BYTE;
+
+  return pos;
+}
+
+}  // namespace esphome::zigbee_proxy
+
+#endif  // USE_ZIGBEE_PROXY

esphome/components/zigbee_proxy/ash_protocol.h

@@ -0,0 +1,115 @@
+#pragma once
+
+#include <cstdint>
+#include <cstddef>
+
+namespace esphome::zigbee_proxy {
+
+// ASH Protocol Constants
+static constexpr uint8_t ASH_FLAG_BYTE = 0x7E;        // Frame delimiter
+static constexpr uint8_t ASH_ESCAPE_BYTE = 0x7D;      // Escape/substitution byte
+static constexpr uint8_t ASH_XOR_BYTE = 0x20;         // XOR mask for escaped bytes
+static constexpr uint8_t ASH_SUBSTITUTE_BYTE = 0x18;  // Substitution for invalid bytes
+
+static constexpr uint8_t ASH_XON_BYTE = 0x11;     // Resume transmission
+static constexpr uint8_t ASH_XOFF_BYTE = 0x13;    // Pause transmission
+static constexpr uint8_t ASH_CANCEL_BYTE = 0x1A;  // Discards the partial frame before it
+
+// A reserved byte can never appear literally inside a frame; it is escaped as
+// ESCAPE followed by the byte XOR 0x20. Rejecting frames that contain one is what
+// eliminates most non-ASH traffic before its CRC is ever computed: real firmware
+// images and Spinel payloads are dense in 0x11/0x13/0x18/0x1A.
+inline bool ash_is_reserved(uint8_t byte) {
+  return byte == ASH_FLAG_BYTE || byte == ASH_ESCAPE_BYTE || byte == ASH_XON_BYTE || byte == ASH_XOFF_BYTE ||
+         byte == ASH_SUBSTITUTE_BYTE || byte == ASH_CANCEL_BYTE;
+}
+
+// CRC-CCITT (init 0xFFFF, polynomial 0x1021, transmitted big-endian). Note this is a
+// different variant from the Kermit FCS that Spinel/HDLC-lite uses over the same
+// 0x7E framing, so Spinel frames systematically fail this check.
+uint16_t ash_crc16(const uint8_t *data, size_t length, uint16_t init = 0xFFFF);
+
+// Buffer size configuration
+#ifdef ZIGBEE_PROXY_BUFFER_SIZE
+static constexpr size_t MAX_ASH_FRAME_SIZE = ZIGBEE_PROXY_BUFFER_SIZE;
+#else
+#ifdef USE_ESP8266
+static constexpr size_t MAX_ASH_FRAME_SIZE = 512;  // Limited RAM on ESP8266
+#else
+static constexpr size_t MAX_ASH_FRAME_SIZE = 1024;  // Full buffer on ESP32/RP2040
+#endif
+#endif
+
+// Protocol limits
+static constexpr uint8_t ASH_MAX_SEQUENCE = 7;       // 3-bit sequence number (0-7)
+static constexpr uint8_t ASH_TX_WINDOW_SIZE = 1;     // Only 1 unacknowledged frame allowed
+static constexpr uint8_t ASH_MAX_RETRIES = 5;        // Maximum retransmission attempts
+static constexpr uint16_t ASH_CRC_INIT = 0xFFFF;     // CRC-CCITT initial value
+static constexpr uint32_t ASH_RESET_TIMEOUT = 3000;  // RST/RSTACK timeout in milliseconds
+
+// IEEE address size
+static constexpr size_t ZIGBEE_IEEE_ADDR_SIZE = 8;  // 64-bit IEEE address
+
+// ASH data randomization. The Data Field of every DATA frame is XORed with a
+// pseudo-random sequence (LFSR seeded at 0x42, polynomial 0xB8) before
+// transmission and again after reception; the operation is its own inverse.
+//
+// Proxied client traffic must NOT be passed through this: the client randomizes
+// and the NCP derandomizes, so payloads travel end to end untouched and the
+// proxy stays transparent. Apply it only to frames this component originates or
+// consumes itself, i.e. the boot-harvest EZSP commands and their responses.
+// Sending an unrandomized command makes the NCP derandomize it into garbage and
+// answer with an error frame that decodes as a plausible-looking wrong value.
+void ash_randomize(uint8_t *data, size_t length);
+
+// ASH Frame Types (encoded in control byte)
+// DATA format:    0ffrPPPP - bit 7=0, bits 6-4=frmNum, bit 3=reTx, bits 2-0=ackNum
+// ACK/NAK format: 10XnrPPP - bit 5 distinguishes ACK(0) from NAK(1)
+enum class AshFrameType : uint8_t {
+  DATA = 0x00,    // Data frame (bit 7 = 0)
+  ACK = 0x80,     // Acknowledge frame (100nrPPP, bit 5 = 0)
+  NAK = 0xA0,     // Negative acknowledge (101nrPPP, bit 5 = 1)
+  RST = 0xC0,     // Reset request (bits 7-6 = 11, bits 2-0 = 000)
+  RSTACK = 0xC1,  // Reset acknowledgment (bits 7-6 = 11, bits 2-0 = 001)
+  ERROR = 0xC2,   // Error indication (bits 7-6 = 11, bits 2-0 = 010)
+};
+
+// ASH Connection State
+enum class AshState : uint8_t {
+  DISCONNECTED,  // Initial state, no connection
+  CONNECTING,    // Sent RST, waiting for RSTACK
+  CONNECTED,     // Normal operation
+  FAILED,        // Too many errors/timeouts, requires reset
+};
+
+// Frame Parsing State Machine
+enum class ParsingState : uint8_t {
+  WAIT_FLAG_START,  // Looking for frame start FLAG (0x7E)
+  WAIT_CONTROL,     // Reading control byte
+  WAIT_DATA,        // Reading data payload
+  WAIT_CRC_HIGH,    // Reading CRC high byte
+  WAIT_CRC_LOW,     // Reading CRC low byte
+  WAIT_FLAG_END,    // Expecting end FLAG (0x7E)
+};
+
+// Bootloader detection states
+enum class BootloaderState : uint8_t {
+  NORMAL,    // Normal operation
+  DETECTED,  // Bootloader mode detected
+  MENU,      // In bootloader menu
+};
+
+// EZSP Error Codes (from ERROR frame)
+enum class EzspError : uint8_t {
+  VERSION_NOT_SET = 0x00,
+  RESET_UNKNOWN = 0x01,
+  RESET_EXTERNAL = 0x02,
+  RESET_POWER_ON = 0x03,
+  RESET_WATCHDOG = 0x04,
+  RESET_ASSERT = 0x05,
+  RESET_BOOTLOADER = 0x06,
+  RESET_SOFTWARE = 0x07,
+  EXCEEDED_MAXIMUM_ACK_TIMEOUT_COUNT = 0x51,
+};
+
+}  // namespace esphome::zigbee_proxy

esphome/components/zigbee_proxy/ezsp_commands.h

@@ -0,0 +1,88 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+
+namespace esphome::zigbee_proxy {
+
+// EZSP Protocol Versions
+static constexpr uint8_t EZSP_MIN_VERSION = 13;  // Minimum supported version
+static constexpr uint8_t EZSP_MAX_VERSION = 13;  // Maximum version we request
+
+// EZSP Frame Control bits
+static constexpr uint8_t EZSP_FRAME_CONTROL_COMMAND = 0x00;   // Host to NCP
+static constexpr uint8_t EZSP_FRAME_CONTROL_RESPONSE = 0x80;  // NCP to Host
+static constexpr uint8_t EZSP_FRAME_CONTROL_CALLBACK = 0x90;  // Async callback from NCP
+
+// High byte of the 16-bit frame control, carrying frameFormatVersion = 1. Every
+// command after version negotiation must set this: omitting it leaves the NCP
+// reading the frame ID's low byte as frame_control_high, so the command is
+// discarded and the reply is an error frame rather than the expected response.
+static constexpr uint8_t EZSP_FRAME_CONTROL_EXTENDED = 0x01;
+
+// Legacy EZSP frame format (v4-v7): [sequence] [frame_control] [frame_id]
+// Extended EZSP frame format (v8+): [sequence] [frame_control_low] [frame_control_high] [frame_id_low] [frame_id_high]
+//
+// Only the `version` command and its response use the legacy format, because the
+// NCP starts in legacy mode and has not yet learned the negotiated version.
+// Everything after that is extended, with no per-NCP exceptions.
+
+// EZSP Frame IDs - Callbacks (NCP to host, async)
+static constexpr uint16_t EZSP_STACK_STATUS_HANDLER = 0x0019;  // Stack up/down notification
+
+// EZSP Frame IDs - Commands (host to NCP)
+static constexpr uint16_t EZSP_VERSION = 0x0000;                 // Version negotiation
+static constexpr uint16_t EZSP_GET_EUI64 = 0x0026;               // Get IEEE address
+static constexpr uint16_t EZSP_GET_NETWORK_PARAMETERS = 0x0028;  // Get network parameters
+static constexpr uint16_t EZSP_GET_TOKEN_DATA = 0x0102;          // Read an NVM3 token
+
+// Extended EZSP header: [sequence] [frame_control_lo] [frame_control_hi] [id_lo] [id_hi]
+static constexpr size_t EZSP_EXTENDED_HEADER_SIZE = 5;
+
+// Network metadata comes straight out of NVM3 instead of from a running stack.
+// NVM3KEY_STACK_NODE_DATA holds the PAN ID, channel, extended PAN ID and node type of
+// the network this radio is commissioned onto, and reading it requires nothing beyond a
+// completed version negotiation: no stack configuration, no networkInit, no waiting on
+// stackStatusHandler, and above all no joining the network -- so simply plugging the
+// device in never brings the radio up.
+//
+// Note the 0x0001 domain prefix on the NVM3 object key. The bare creator ID
+// 0x0000EE64 is a different thing and getTokenData answers FAIL for it.
+static constexpr uint32_t NVM3KEY_STACK_NODE_DATA = 0x0001EE64;
+
+// getTokenData response: [status (4)] [length (4)] [value (length)]
+static constexpr size_t TOKEN_DATA_VALUE_OFFSET = 8;
+
+// NV3StackNodeData value layout (16 bytes, little-endian):
+// [panId (2)] [radioTxPower (1)] [radioFreqChannel (1)] [stackProfile (1)]
+// [nodeType (1)] [zigbeeNodeId (2)] [extendedPanId (8)]
+static constexpr size_t NV3_NODE_DATA_SIZE = 16;
+static constexpr size_t NV3_NODE_DATA_PAN_ID_OFFSET = 0;
+static constexpr size_t NV3_NODE_DATA_CHANNEL_OFFSET = 3;
+static constexpr size_t NV3_NODE_DATA_NODE_TYPE_OFFSET = 5;
+static constexpr size_t NV3_NODE_DATA_EXT_PAN_ID_OFFSET = 8;
+
+// A radio with no network still has the token, holding a sentinel rather than being
+// absent: panId reads 0xFFFF and nodeType reads UNKNOWN_DEVICE. Detecting "no network"
+// therefore means inspecting nodeType, not treating the read as failed.
+static constexpr uint8_t NV3_NODE_TYPE_UNKNOWN_DEVICE = 0x00;
+
+// Status codes (subset). EZSP v13+ / EmberZNet 8.x report sl_status_t, not the
+// legacy 8-bit EmberStatus.
+enum class SlStatus : uint8_t {
+  OK = 0x00,
+  NETWORK_UP = 0x15,
+  NETWORK_DOWN = 0x16,
+};
+
+// getNetworkParameters response layout, used when sniffing a client's own traffic. This
+// is a different shape from the NV3 token the boot harvest reads: 25 bytes of
+// [status (4)] [nodeType (1)] [extendedPanId (8)] [panId (2)] [radioTxPower (1)]
+// [radioChannel (1)] [joinMethod (1)] [nwkManagerId (2)] [nwkUpdateId (1)] [channels (4)]
+static constexpr size_t NETWORK_PARAMS_RESPONSE_SIZE = 25;
+static constexpr size_t NETWORK_PARAMS_STATUS_OFFSET = 0;
+static constexpr size_t NETWORK_PARAMS_EXT_PAN_ID_OFFSET = 5;
+static constexpr size_t NETWORK_PARAMS_PAN_ID_OFFSET = 13;
+static constexpr size_t NETWORK_PARAMS_CHANNEL_OFFSET = 16;
+
+}  // namespace esphome::zigbee_proxy

esphome/components/zigbee_proxy/zigbee_proxy.h

@@ -0,0 +1,250 @@
+#pragma once
+
+#include "esphome/core/defines.h"
+#ifdef USE_ZIGBEE_PROXY
+
+#include "esphome/components/api/api_connection.h"
+#include "esphome/components/api/api_pb2.h"
+#include "esphome/components/serial_proxy/serial_proxy.h"
+#include "esphome/core/component.h"
+#include "esphome/core/helpers.h"
+#include "ash_protocol.h"
+#include "ash_detector.h"
+
+#include <array>
+
+namespace esphome::zigbee_proxy {
+
+// Timeout configuration structure
+struct TimeoutConfig {
+  uint32_t initial_timeout_ms{1600};  // Initial ACK timeout
+  uint32_t min_timeout_ms{400};       // Minimum adaptive timeout
+  uint32_t max_timeout_ms{3200};      // Maximum adaptive timeout
+  uint32_t current_timeout_ms{1600};  // Current adaptive timeout
+};
+
+// Network information structure
+struct NetworkInfo {
+  std::array<uint8_t, ZIGBEE_IEEE_ADDR_SIZE> ieee_address{};
+  uint16_t pan_id{0};
+  std::array<uint8_t, 8> extended_pan_id{};
+  uint8_t channel{0};
+  bool valid{false};
+};
+
+enum ZigbeeProxyFeature : uint32_t {
+  FEATURE_ZIGBEE_PROXY_ENABLED = 1 << 0,
+  // Set only when the harvest actually read a network off the radio. Without it a client
+  // cannot tell "a Zigbee radio with no network formed" from "not a Zigbee radio at all"
+  // -- both otherwise present as ENABLED with an all-zero payload, and the second happens
+  // whenever the NCP has been reflashed to Thread or is simply not responding.
+  FEATURE_ZIGBEE_NETWORK_INFO_VALID = 1 << 1,
+};
+
+// Boot-time initialization state machine
+enum class BootState : uint8_t {
+  IDLE,               // Not initializing
+  WAIT_RSTACK,        // Sent RST, waiting for RSTACK
+  SEND_VERSION,       // Send EZSP version command
+  WAIT_VERSION,       // Waiting for version response
+  SEND_TOKEN_DATA,    // Send getTokenData(NVM3KEY_STACK_NODE_DATA)
+  WAIT_TOKEN_DATA,    // Waiting for token data response
+  SEND_GET_EUI64,     // Send getEui64 command
+  WAIT_EUI64,         // Waiting for EUI64 response
+  SEND_FINAL_RST,     // Send final RST to reset NCP
+  WAIT_FINAL_RSTACK,  // Waiting for final RSTACK
+  COMPLETE,           // Boot sequence complete
+  FAILED,             // Boot sequence failed
+};
+
+// Watches a `serial_proxy` port carrying an EZSP NCP and reports what it learns about the
+// Zigbee network. It never carries client traffic: the serial proxy owns the port and the
+// bytes, and this component only observes them, plus two exceptions where it writes to the
+// port itself -- the boot-time metadata harvest, which runs before any client connects, and
+// the ASH acknowledgements a client asks it to send on its behalf.
+class ZigbeeProxy : public serial_proxy::SerialProxyTap, public Component {
+ public:
+  ZigbeeProxy();
+
+  void setup() override;
+  void loop() override;
+  void dump_config() override;
+  float get_setup_priority() const override;
+  bool can_proceed() override;
+
+  void set_serial_proxy(serial_proxy::SerialProxy *parent) { this->parent_ = parent; }
+
+  // SerialProxyTap
+  void on_device_rx(const uint8_t *data, size_t len) override;
+  void on_client_tx(const uint8_t *data, size_t len) override;
+  bool tap_needs_port() const override {
+    if (this->boot_sequence_active_) {
+      return true;
+    }
+    // A pending re-harvest waits for the port to go idle. Starting one under a subscriber
+    // would inject our own ASH frames into whatever it is doing -- most likely the very
+    // firmware upload that invalidated the metadata.
+    return this->reharvest_pending_ && this->parent_->get_api_connection() == nullptr;
+  }
+
+  /// The port stopped handling our protocol, so whatever we know about the radio may no
+  /// longer be true -- a client asking for raw bytes is usually about to reflash it.
+  void on_protocol_disabled() override;
+
+  /// The radio was unplugged or a new one appeared; metadata describes neither.
+  void on_device_presence_changed_(bool connected);
+
+  // API integration
+  void api_connection_authenticated(api::APIConnection *conn);
+  void zigbee_proxy_request(api::APIConnection *api_connection, const api::ZigbeeProxyRequest &msg);
+
+  // Feature flags
+  uint32_t get_feature_flags() const {
+    uint32_t flags = ZigbeeProxyFeature::FEATURE_ZIGBEE_PROXY_ENABLED;
+    if (this->network_info_.valid) {
+      flags |= ZigbeeProxyFeature::FEATURE_ZIGBEE_NETWORK_INFO_VALID;
+    }
+    return flags;
+  }
+
+  // Network information accessors
+  const NetworkInfo &get_network_info() const { return this->network_info_; }
+  uint64_t get_ieee_address() const;
+
+  // Timeout configuration (callable from Python/API)
+  void set_timeout_config(uint32_t initial_ms, uint32_t min_ms, uint32_t max_ms);
+  void set_initial_timeout(uint32_t timeout_ms) { this->timeout_config_.initial_timeout_ms = timeout_ms; }
+  void set_min_timeout(uint32_t timeout_ms) { this->timeout_config_.min_timeout_ms = timeout_ms; }
+  void set_max_timeout(uint32_t timeout_ms) { this->timeout_config_.max_timeout_ms = timeout_ms; }
+
+ protected:
+  // ASH Protocol State Machine
+  void reset_ash_protocol_();
+  void send_rst_frame_();
+  void handle_rstack_frame_(const uint8_t *data, size_t length);
+  void handle_error_frame_(const uint8_t *data, size_t length);
+  // Applies a frame's ackNum to the pending TX frame. Returns true if it
+  // acknowledged one. Valid on DATA, ACK and NAK frames alike.
+  bool handle_ack_num_(uint8_t ack_num);
+  bool send_ack_frame_(uint8_t ack_num);
+  bool send_nak_frame_(uint8_t ack_num);
+  bool send_data_frame_(const uint8_t *data, size_t length, bool retransmit = false);
+
+  // Frame parsing and building (implemented in ash_protocol.cpp)
+  bool parse_byte_(uint8_t byte);
+  void parse_control_byte_(uint8_t control);
+  bool validate_frame_crc_();
+  // Builds a stuffed frame into output; returns 0 if the frame (worst case 2*length + 8
+  // bytes after byte stuffing) would exceed capacity.
+  size_t build_frame_(uint8_t *output, size_t capacity, const uint8_t *data, size_t length, AshFrameType type,
+                      uint8_t frame_num = 0, uint8_t ack_num = 0, bool retx = false);
+  uint16_t calculate_crc_(const uint8_t *data, size_t length, uint16_t init = ASH_CRC_INIT);
+
+  // Sequence number management
+  void increment_tx_sequence_() { this->tx_sequence_ = (this->tx_sequence_ + 1) & ASH_MAX_SEQUENCE; }
+  void increment_rx_sequence_() { this->rx_sequence_ = (this->rx_sequence_ + 1) & ASH_MAX_SEQUENCE; }
+
+  // Timeout management
+  void update_adaptive_timeout_(uint32_t measured_rtt_ms);
+  void start_ack_timer_() { this->ack_timer_start_ = millis(); }
+  bool check_ack_timeout_();
+
+  // Retransmission
+  void handle_retransmission_();
+  void clear_tx_buffer_() {
+    this->tx_buffer_pending_ = false;
+    this->tx_retry_count_ = 0;
+  }
+
+  // Boot-time NCP initialization
+  void advance_boot_state_();
+  void check_boot_timeouts_();
+  void handle_boot_data_frame_(const uint8_t *data, size_t length);
+  void send_ezsp_version_();
+  void send_get_eui64_();
+  void send_get_token_data_();
+  void handle_version_response_(const uint8_t *data, size_t length);
+  void handle_eui64_response_(const uint8_t *data, size_t length);
+  void handle_token_data_response_(const uint8_t *data, size_t length);
+
+  // IEEE address and network info
+  bool set_ieee_address_(const uint8_t *new_address);
+  void send_network_info_changed_msg_(api::APIConnection *conn = nullptr);
+
+  // WiFi/Zigbee channel conflict detection
+  void check_wifi_zigbee_conflict_();
+
+  // Bootloader detection (fed consecutive raw byte pairs while not CONNECTED)
+  void check_bootloader_mode_(uint8_t prev_byte, uint8_t byte);
+
+  // Reads network metadata out of a proxied getNetworkParameters response. Read-only, so a
+  // misparse costs a missed update rather than corrupting anything.
+  void sniff_network_info_(const uint8_t *frame, size_t length);
+  // Invalidates network metadata when the stack reports it has left the network.
+  void sniff_stack_status_(const uint8_t *frame, size_t length);
+
+  // NCP-side ASH buffers
+  std::array<uint8_t, MAX_ASH_FRAME_SIZE> rx_buffer_;
+  std::array<uint8_t, MAX_ASH_FRAME_SIZE> tx_buffer_;
+  std::array<uint8_t, MAX_ASH_FRAME_SIZE> tx_pending_buffer_;  // For retransmission
+
+  // Network information
+  NetworkInfo network_info_;
+
+  // Timeout configuration
+  TimeoutConfig timeout_config_;
+
+  // The port this component observes. Owns the UART and the bytes; every write we make
+  // goes through it.
+  serial_proxy::SerialProxy *parent_{nullptr};
+
+  uint32_t setup_time_{0};       // Time when last RST frame was sent
+  uint32_t boot_start_time_{0};  // Time when the boot sequence began (for overall timeout)
+  uint32_t ack_timer_start_{0};  // Time when ACK timer started
+  uint32_t last_rtt_ms_{0};      // Last measured round-trip time
+
+  uint16_t rx_buffer_index_{0};    // Index for populating rx_buffer_
+  uint16_t tx_pending_length_{0};  // Length of pending TX frame for retransmission
+  uint16_t calculated_crc_{0};     // CRC calculated during frame reception
+
+  uint8_t tx_sequence_{0};           // TX sequence number (0-7)
+  uint8_t rx_sequence_{0};           // RX sequence number (0-7)
+  uint8_t tx_retry_count_{0};        // Number of retransmission attempts
+  uint8_t tx_pending_frame_num_{0};  // Frame number of pending TX frame
+  uint8_t last_ack_sent_{0};         // Last ACK number sent
+  uint8_t last_rx_byte_{0};          // Previous raw RX byte (bootloader detection)
+
+  AshState ash_state_{AshState::DISCONNECTED};
+  ParsingState parsing_state_{ParsingState::WAIT_FLAG_START};
+  BootloaderState bootloader_state_{BootloaderState::NORMAL};
+  BootState boot_state_{BootState::IDLE};
+
+  uint8_t ezsp_version_{0};            // NCP's EZSP protocol version
+  uint8_t ezsp_sequence_{0};           // EZSP frame sequence number
+  uint8_t ezsp_requested_version_{0};  // Version we last requested (for re-negotiation)
+  // The NCP keeps using legacy framing until `version` is repeated in the
+  // negotiated (extended) format; until then it rejects every extended command
+  // with frame ID 0x0058. Tracks whether that second handshake has happened.
+  bool ezsp_version_confirmed_{false};
+
+  bool tx_buffer_pending_{false};  // True if waiting for ACK from NCP
+  bool escape_next_byte_{false};   // True if next NCP byte should be unescaped
+
+  bool boot_sequence_active_{false};  // True during boot-time init
+  // Set when the metadata was discarded and a fresh harvest is owed once the port frees up
+  bool reharvest_pending_{false};
+  // Last observed device presence, for spotting a hot-plug
+  bool was_connected_{false};
+  // Earliest millis() at which a pending re-harvest may start
+  uint32_t reharvest_after_{0};
+
+  // Decides when acknowledging on the client's behalf is safe. Armed only by the ASH
+  // session handshake, so a bootloader or Thread NCP never triggers it.
+  AshDetector detector_;
+};
+
+extern ZigbeeProxy *global_zigbee_proxy;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
+
+}  // namespace esphome::zigbee_proxy
+
+#endif  // USE_ZIGBEE_PROXY

esphome/core/config.py

@@ -555,14 +555,7 @@ NATIVE_ARDUINO_PIO_OPTIONS = frozenset({"board_build.f_cpu", "board_build.ldscri
 # that is stored rather than translated away. Consumed by the esp8266 native
 # backend (later in this chain) for its ignored-option warning; defined here
 # so it stays adjacent to the routing.
-# build_src_flags and board_build.flash_mode: set unconditionally by
-# esp8266/__init__ and read by the native generator; not user-routable, so
-# not in the set above
-NATIVE_ARDUINO_CONSUMED_PIO_OPTIONS = NATIVE_ARDUINO_PIO_OPTIONS | {
-    "lib_ignore",
-    "build_src_flags",
-    "board_build.flash_mode",
-}
+NATIVE_ARDUINO_CONSUMED_PIO_OPTIONS = NATIVE_ARDUINO_PIO_OPTIONS | {"lib_ignore"}
 
 
 @coroutine_with_priority(CoroPriority.FINAL)

esphome/core/defines.h

@@ -180,6 +180,7 @@
 #define USE_SENSOR
 #define USE_SENSOR_FILTER
 #define USE_SERIAL_PROXY
+#define USE_SERIAL_PROXY_TAP
 #define USE_SETUP_PRIORITY_OVERRIDE
 #define USE_STATUS_LED
 #define USE_STATUS_SENSOR
@@ -197,6 +198,7 @@
 #define USE_VALVE
 #define USE_WATER_HEATER
 #define USE_WATER_HEATER_VISUAL_OVERRIDES
+#define USE_ZIGBEE_PROXY
 #define USE_ZWAVE_PROXY
 
 // Feature flags which do not work for zephyr
@@ -393,6 +395,10 @@
 #define USB_HOST_MAX_REQUESTS 16
 #define USB_HOST_MAX_PACKET_SIZE 64
 #define USB_UART_OUTPUT_CHUNK_COUNT 5
+// USB identity on serial proxy ports needs the usb_host stack
+#ifdef USE_ESP32
+#define USE_SERIAL_PROXY_USB_INFO
+#endif
 
 #ifdef USE_ARDUINO
 #define USE_ARDUINO_VERSION_CODE VERSION_CODE(3, 3, 7)

esphome/espidf/framework.py

@@ -16,7 +16,6 @@ from esphome.build_helpers.ccache import (
     parse_enable_env,
     resolve_ccache_path,
 )
-from esphome.build_helpers.pch import ccache_pch_env
 from esphome.build_helpers.tools_cache import IDF_TOOLS_CACHE, tools_cache_path
 from esphome.core import Version
 from esphome.framework_helpers import (
@@ -1206,33 +1205,15 @@ def _ccache_env() -> dict[str, str]:
 
     Only values the user has not already set in the environment are returned, so
     a custom ``CCACHE_DIR`` / ``CCACHE_MAXSIZE`` / etc. is respected.
-    The pch settings add ``time_macros`` sloppiness process-wide; the visible
-    effect is a cached TU can keep an older ``esp_app_desc`` build timestamp.
-    """
-    if not _ccache_enabled():
-        # The raw knob value (e.g. "disable") is still inherited by idf.py
-        # via os.environ, where a non-false-constant string reads as
-        # truthy; export the canonical off spelling instead
-        return {"IDF_CCACHE_ENABLE": "0"}
-
-    env = ccache_defaults_env(get_idf_tools_path() / "ccache")
-    env.update(ccache_pch_env())
-    # Exactly one canonical spelling ever reaches idf.py, whatever the
-    # accepted input spelling was ("enable", "yes", ...)
-    env["IDF_CCACHE_ENABLE"] = "1"
-    return env
-
-
-def _ccache_enabled() -> bool:
-    """Whether ESP-IDF compiles run under ccache.
-
-    IDF_CCACHE_ENABLE (the backend-native knob) wins over the shared
-    ESPHOME_CCACHE_ENABLE; when unset, enabled iff a runnable binary is
-    on PATH.
     """
+    # IDF_CCACHE_ENABLE (the backend-native knob) wins over the shared
+    # ESPHOME_CCACHE_ENABLE.
     idf_knob = parse_enable_env("IDF_CCACHE_ENABLE")
     if idf_knob is False:
-        return False
+        # The raw value (e.g. "disable") is still inherited by idf.py via
+        # os.environ, where a non-false-constant string reads as truthy;
+        # export the canonical off spelling instead
+        return {"IDF_CCACHE_ENABLE": "0"}
     if idf_knob is True:
         # Forced on ignores the runnability verdict, but the outcome is
         # worth saying out loud. Probed directly (not via the resolver,
@@ -1252,8 +1233,17 @@ def _ccache_enabled() -> bool:
                 "IDF_CCACHE_ENABLE=1 forces on the ccache at %s even though "
                 "it failed to run; idf.py will use it anyway",
             )
-        return True
-    return resolve_ccache_path() is not None
+    elif resolve_ccache_path() is None:
+        # ESP-IDF silently skips ccache without the binary; export the
+        # canonical off spelling so an unparsable inherited value (or a
+        # probe-rejected ccache idf.py would still find) cannot enable it
+        return {"IDF_CCACHE_ENABLE": "0"}
+
+    env = ccache_defaults_env(get_idf_tools_path() / "ccache")
+    # Exactly one canonical spelling ever reaches idf.py, whatever the
+    # accepted input spelling was ("enable", "yes", ...)
+    env["IDF_CCACHE_ENABLE"] = "1"
+    return env
 
 
 def get_framework_env(

esphome/espidf/toolchain.py

@@ -1,6 +1,5 @@
 """ESP-IDF direct build API for ESPHome."""
 
-from contextlib import suppress
 from dataclasses import dataclass, field
 import hashlib
 import json
@@ -529,20 +528,6 @@ def run_compile(config, verbose: bool) -> int:
             return result.returncode
         _patch_memory_segments()
 
-    # After every reconfigure so compile_commands and sdkconfig are settled.
-    # An optional speedup must never abort the build
-    from esphome.build_gen.espidf import discard_pch, prepare_pch
-
-    try:
-        prepare_pch()
-    except Exception:  # noqa: BLE001  # pylint: disable=broad-exception-caught
-        # Discard so a stale .gch can never be consumed
-        with suppress(OSError):
-            discard_pch()
-        _LOGGER.warning(
-            "Precompiled header setup failed; compiling without it", exc_info=True
-        )
-
     # Build
     args = []
 

esphome/platformio/pch.py.script

@@ -1,364 +0,0 @@
-import hashlib
-import os
-from pathlib import Path
-import posixpath
-import re
-import shlex
-import stat
-import subprocess
-import traceback
-
-# pylint: disable=E0602
-Import("env")  # noqa: F821
-_projenv_error = None
-try:
-    Import("projenv")  # noqa: F821
-except Exception as err:  # noqa: BLE001 -- not exported under -t nobuild
-    projenv = None
-    _projenv_error = err
-
-# Precompile the src force-includes plus defines.h and force-include the
-# result into C++ src compiles only; their preprocessed output is unchanged.
-# Registration is gated host-side (pch_enabled()). Keep the closure, ccache
-# values, and stamp flow in sync with build_helpers/pch.py.
-
-# Compiler failures that clear on their own must not latch the .failed marker
-_TRANSIENT_ERRORS = ("No space left", "Cannot allocate", "Resource temporarily")
-
-_INCLUDE_RE = re.compile(rb'^\s*#\s*include\s+["<]([^">]+)[">]', re.MULTILINE)
-_CORE_HEADER = "esphome/core/defines.h"
-
-
-def _raise_walk_error(err: OSError) -> None:
-    raise err
-
-
-def _resolves_dir(path: Path) -> bool:
-    """False when missing; other stat failures propagate."""
-    try:
-        return stat.S_ISDIR(path.stat().st_mode)
-    except (FileNotFoundError, NotADirectoryError):
-        return False
-
-
-def _resolves(path: Path) -> bool:
-    """False when missing; other stat failures propagate (identity unknown)."""
-    try:
-        return stat.S_ISREG(path.stat().st_mode)
-    except (FileNotFoundError, NotADirectoryError):
-        return False
-
-
-def _include_closure(src_dir: Path, roots: list) -> dict:
-    """Quoted-include closure: src-relative name -> contents (mirror of
-    build_helpers/pch.py)."""
-    seen = {}
-    stack = [(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 _resolves(src_dir / rel):
-                break
-        else:
-            continue
-        if rel in seen:
-            continue
-        try:
-            data = (src_dir / rel).read_bytes()
-        except OSError as err:
-            # A marker would truncate the transitive walk; fail closed
-            print(f"ESPHome: could not read {rel} for the pch checksum: {err}")
-            raise
-        seen[rel] = data
-        parent = posixpath.dirname(rel)
-        stack.extend(
-            (inc.decode(errors="surrogateescape"), parent)
-            for inc in _INCLUDE_RE.findall(data)
-        )
-    return seen
-
-
-def _shell_arg(element) -> str | None:
-    """One compiler argv from one SCons element, matching the real spawn:
-    spaced elements pass whole, the rest get one shell unquote (skipped on
-    Windows, where shlex would eat path backslashes)."""
-    arg = str(element)
-    if " " in arg or os.name == "nt":
-        return arg.replace('\\"', '"')
-    if not arg.strip():
-        return arg
-    try:
-        tokens = shlex.split(arg)
-    except ValueError as err:
-        print(f"ESPHome: could not lex flag {arg!r} for the pch: {err}")
-        return None
-    if len(tokens) != 1:
-        # A flag the model cannot reproduce would diverge the .gch's flags
-        print(f"ESPHome: cannot model flag {arg!r} for the pch")
-        return None
-    return tokens[0]
-
-
-def _compile_gch(cxx, flags, header: Path, gch: Path, proj_dir: Path):
-    """Compile the .gch, then probe that the toolchain can load it back
-    (GCC 10 on macOS arm64 rejects its own per-process). Returns an error
-    string or None; OSError propagates as transient."""
-    result = subprocess.run(  # noqa: PLW1510
-        [cxx, "-x", "c++-header", *flags, "-c", str(header), "-o", str(gch)],
-        cwd=proj_dir,
-        # C locale keeps diagnostics matchable by _TRANSIENT_ERRORS
-        env={**os.environ, "LC_ALL": "C"},
-        capture_output=True,
-        text=True,
-    )
-    if result.returncode < 0:
-        # Signal-killed (OOM, ^C): route to the transient no-marker path
-        raise OSError(f"compiler killed by signal {-result.returncode}")
-    if result.returncode != 0:
-        return result.stderr
-    # -MF is only legal alongside a dependency flag; pass it solely to
-    # redirect a depfile that -MD/-MMD in the flags would otherwise write
-    dep_redirect = (
-        ["-MF", os.devnull]
-        if any(f in ("-MD", "-MMD", "-M", "-MM") for f in flags)
-        else []
-    )
-    probe = subprocess.run(  # noqa: PLW1510
-        [
-            cxx,
-            *flags,
-            *dep_redirect,
-            "-Winvalid-pch",
-            "-include",
-            str(header),
-            "-fsyntax-only",
-            "-x",
-            "c++",
-            "-",
-        ],
-        cwd=proj_dir,
-        env={**os.environ, "LC_ALL": "C"},
-        input="",
-        capture_output=True,
-        text=True,
-    )
-    if probe.returncode < 0:
-        raise OSError(f"probe killed by signal {-probe.returncode}")
-    if probe.returncode != 0 or ".gch" in probe.stderr:
-        return f"toolchain cannot load the pch: {probe.stderr.strip()}"
-    return None
-
-
-def _read_stamp(path: Path) -> str:
-    """A corrupt sidecar must read as stale, not kill the pch forever."""
-    try:
-        return path.read_text(encoding="utf-8").strip()
-    except (OSError, UnicodeDecodeError):
-        return ""
-
-
-def _setup_pch() -> None:
-    if projenv is None:
-        # Expected under -t nobuild; anything else must leave a trail
-        print(f"ESPHome: projenv unavailable ({_projenv_error}); skipping pch")
-        return
-    # Project root: SCons compiles run here, so the relative -include
-    # resolves; an absolute path would break cross-device ccache sharing.
-    proj_dir = Path(env.subst("$PROJECT_DIR"))  # noqa: F821
-    src_dir = Path(env.subst("$PROJECT_SRC_DIR"))  # noqa: F821
-    header = proj_dir / "esphome_pch.h"
-    gch = Path(f"{header}.gch")
-    sum_path = Path(f"{gch}.sum")
-
-    cxx = projenv.subst("$CXX")  # noqa: F821
-    # The header holds the -include entries itself, so the .gch compile must
-    # not see them; consumers keep theirs, which the .gch then satisfies.
-    flags = []
-    include_headers = []
-    raw_args = [
-        _shell_arg(element)
-        for element in projenv.subst_list("$CXXFLAGS $CCFLAGS $_CCCOMCOM")[0]  # noqa: F821
-    ]
-    if any(arg is None for arg in raw_args):
-        print("ESPHome: skipping precompiled header: unmodelable flag")
-        return
-    flag_it = iter(raw_args)
-    for tok in flag_it:
-        if tok == "-include":
-            include_headers.append(next(flag_it, ""))
-        elif tok.startswith("-include") and not tok.startswith("-include-"):
-            include_headers.append(tok[len("-include") :])
-        else:
-            flags.append(tok)
-    if any(not name for name in include_headers):
-        print("ESPHome: build_src_flags has a trailing -include; skipping pch")
-        return
-    # Fold only relative names resolving under src/: consumers keep their
-    # own -include entries, so folding an unguarded user header would
-    # include it twice; unfolded ones stay consumer-only.
-    try:
-        folded = [
-            name
-            for name in include_headers
-            if not Path(name).is_absolute() and _resolves(src_dir / name)
-        ]
-    except OSError as err:
-        print(f"ESPHome: skipping precompiled header: {err}")
-        return
-    if unfolded := [n for n in include_headers if n not in folded]:
-        print(f"ESPHome: not precompiling non-src force-includes: {unfolded}")
-    content = "".join(f'#include "{name}"\n' for name in (*folded, _CORE_HEADER))
-
-    digest = hashlib.sha256()
-    digest.update(content.encode(errors="surrogateescape"))
-    digest.update(cxx.encode(errors="surrogateescape"))
-    # Mirror CCACHE_BASEDIR: strip the per-device build path so identical
-    # configs produce identical .sum files and share cache entries
-    flags_id = " ".join(flags)
-    if basedir := os.environ.get("CCACHE_BASEDIR"):
-        flags_id = flags_id.replace(basedir, "")
-    digest.update(flags_id.encode(errors="surrogateescape"))
-    # GCC never validates a .gch against its source headers, and PlatformIO
-    # package paths carry no version, so a package bump must invalidate here
-    platform = env.PioPlatform()  # noqa: F821
-    for package in sorted(platform.packages):
-        try:
-            version = platform.get_package_version(package)
-        except KeyError:
-            # An unresolved manifest must not hash as a constant
-            if platform.get_package(package) is not None:
-                print(f"ESPHome: skipping precompiled header: no version for {package}")
-                return
-            version = None  # absent optional package
-        except Exception as err:  # noqa: BLE001
-            # No trustworthy package identity: a stale .gch could survive
-            print(f"ESPHome: skipping precompiled header: {err}")
-            return
-        digest.update(f"{package}={version}".encode())
-        digest.update(b"\0")
-    try:
-        closure = _include_closure(src_dir, [*folded, _CORE_HEADER])
-    except OSError as err:
-        print(f"ESPHome: skipping precompiled header: {err}")
-        return
-    for rel in sorted(closure):
-        digest.update(rel.encode(errors="surrogateescape"))
-        digest.update(closure[rel])
-        digest.update(b"\0")
-    # Project-local -I dirs (e.g. rp2's lwip_override) hold generated
-    # headers the src closure cannot see; hash them too
-    prev = ""
-    try:
-        for tok in flags:
-            inc = tok[2:] if tok.startswith("-I") and len(tok) > 2 else ""
-            if prev == "-I":
-                inc = tok
-            prev = tok
-            if not inc:
-                continue
-            inc_dir = Path(inc)
-            if not (
-                _resolves_dir(inc_dir)
-                and inc_dir.is_relative_to(proj_dir)
-                and not inc_dir.is_relative_to(src_dir)
-                # Library trees never enter the prefix closure; walking them
-                # would read every library file each build
-                and not inc_dir.is_relative_to(proj_dir / ".piolibdeps")
-                and not inc_dir.is_relative_to(proj_dir / ".pioenvs")
-            ):
-                continue
-            local_headers = []
-            # os.walk with onerror: rglob would swallow unlistable subtrees
-            for root, _dirs, files in os.walk(inc_dir, onerror=_raise_walk_error):
-                local_headers.extend(
-                    Path(root) / f
-                    for f in files
-                    if f.endswith((".h", ".hpp", ".hh", ".inc"))
-                )
-            for local in sorted(local_headers):
-                digest.update(str(local.relative_to(proj_dir)).encode())
-                digest.update(local.read_bytes())
-                digest.update(b"\0")
-    except OSError as err:
-        print(f"ESPHome: skipping precompiled header: {err}")
-        return
-    checksum = digest.hexdigest()
-
-    # The ccache .sum sidecar doubles as the freshness stamp
-    if (
-        not header.is_file()
-        or not gch.is_file()
-        or not sum_path.is_file()
-        or (_read_stamp(sum_path) != checksum)
-    ):
-        failed_marker = Path(f"{gch}.failed")
-        if _read_stamp(failed_marker) == checksum:
-            print(
-                "ESPHome: skipping precompiled header (previous attempt "
-                f"failed); delete {failed_marker.name} to retry"
-            )
-            return
-        header.write_text(content, encoding="utf-8")
-        try:
-            error = _compile_gch(cxx, flags, header, gch, proj_dir)
-        except OSError as err:
-            # Transient spawn/IO failure: no marker, retry next build
-            print(f"ESPHome: precompiled header compile did not run: {err}")
-            gch.unlink(missing_ok=True)
-            sum_path.unlink(missing_ok=True)
-            return
-        if error is not None:
-            print("ESPHome: precompiled header failed; compiling without it")
-            print(error)
-            gch.unlink(missing_ok=True)
-            sum_path.unlink(missing_ok=True)
-            if any(m in error for m in _TRANSIENT_ERRORS):
-                # Resource exhaustion clears on its own; retry next build
-                return
-            # Skip retries until a flag/header/platform change alters the checksum
-            failed_marker.write_text(checksum + "\n", encoding="utf-8")
-            return
-        failed_marker.unlink(missing_ok=True)
-        sum_path.write_text(checksum + "\n", encoding="utf-8")
-
-    # Computed first so the flags and env land together: a raise between
-    # them would leave a pch-consuming build without its ccache settings.
-    # projenv["ENV"] aliases os.environ, so these reach all TUs; only
-    # time_macros affects non-pch TUs. User values win.
-    ccache_updates = {
-        key: value
-        for key, value in (
-            ("CCACHE_SLOPPINESS", "pch_defines,time_macros"),
-            ("CCACHE_PCH_EXTSUM", "true"),
-        )
-        if key not in os.environ
-    }
-    sloppiness = os.environ.get("CCACHE_SLOPPINESS")
-    if sloppiness is not None:
-        tokens = {tok.strip() for tok in sloppiness.split(",")}
-        missing = [t for t in ("pch_defines", "time_macros") if t not in tokens]
-        if missing:
-            # Without these ccache declines every pch-consuming compile
-            ccache_updates["CCACHE_SLOPPINESS"] = ",".join((sloppiness, *missing))
-            print(f"ESPHome: adding {','.join(missing)} to CCACHE_SLOPPINESS for the pch")
-    extsum = os.environ.get("CCACHE_PCH_EXTSUM")
-    if extsum is not None and extsum.strip().lower() not in ("1", "true", "yes", "on"):
-        # ccache then hashes the non-reproducible .gch bytes: permanent misses
-        print(f"ESPHome: CCACHE_PCH_EXTSUM={extsum} disables pch caching")
-    # Prepended: GCC only uses a .gch while no other tokens precede it.
-    # The relative name also reaches "pio run -t idedata" output.
-    # -Wno-error: the per-process probe can pass while a later cc1plus
-    # rejects the .gch; that must stay a warning under user -Werror.
-    projenv.Prepend(  # noqa: F821
-        CXXFLAGS=["-Winvalid-pch", "-Wno-error=invalid-pch", "-include", header.name]
-    )
-    projenv["ENV"].update(ccache_updates)  # noqa: F821
-    print("ESPHome: Compiling with precompiled header")
-
-
-try:
-    _setup_pch()
-except Exception:  # noqa: BLE001 -- a speedup must never break the build
-    print("ESPHome: pch internal error; compiling without it")
-    traceback.print_exc()

esphome/platformio/toolchain.py

@@ -289,15 +289,6 @@ def copy_ccache_script() -> None:
     )
 
 
-def copy_pch_script() -> None:
-    """Copy the shared precompiled-header SCons post-script into the build
-    dir; platform components pair it with ``post:pch.py`` in extra_scripts."""
-    copy_file_if_changed(
-        Path(__file__).parent / "pch.py.script",
-        CORE.relative_build_path("pch.py"),
-    )
-
-
 def default_libdeps_dir() -> str:
     """The PLATFORMIO_LIBDEPS_DIR value a pio run defaults to; the package
     prefetch must resolve installed libraries against the same dir."""

esphome/writer.py

@@ -7,7 +7,6 @@ import re
 import time
 
 from esphome import loader
-from esphome.build_helpers.pch import PCH_ARTIFACT_NAMES
 from esphome.compiled_config import save_compiled_config
 from esphome.config import iter_component_configs, iter_components
 from esphome.const import (
@@ -610,20 +609,11 @@ def clean_build(clear_pio_cache: bool = True, *, full: bool = False):
             if idf_path.is_dir():
                 _LOGGER.info("Deleting %s", idf_path)
                 rmtree(idf_path)
-        # The PlatformIO pch artifacts live at the project root so the
-        # relative -include resolves; a partial clean must drop them too
-        for name in PCH_ARTIFACT_NAMES:
-            CORE.relative_build_path(name).unlink(missing_ok=True)
 
-    # The idedata caches are derived from the build but live under the data
-    # dir, not the build path, so they must be removed separately in both
-    # modes. Globbed (name.json plus name.<backend>.json) so a future
-    # backend suffix cannot silently drift out of clean-all.
-    idedata_dir = CORE.relative_internal_path("idedata")
-    for idedata_cache in (
-        *idedata_dir.glob(f"{CORE.name}.json"),
-        *idedata_dir.glob(f"{CORE.name}.*.json"),
-    ):
+    # The idedata cache is derived from the build but lives under the data dir,
+    # not the build path, so it must be removed separately in both modes.
+    idedata_cache = CORE.relative_internal_path("idedata", f"{CORE.name}.json")
+    if idedata_cache.is_file():
         _LOGGER.info("Deleting %s", idedata_cache)
         idedata_cache.unlink()
 

script/determine-jobs.py

@@ -50,7 +50,6 @@ from __future__ import annotations
 
 import argparse
 from collections import Counter
-from collections.abc import Callable
 from enum import StrEnum
 from functools import cache
 import json
@@ -532,53 +531,37 @@ ESP32_PLATFORMIO_TRIGGER_PATH_PREFIXES = ("esphome/platformio/",)
 #   - esphome/build_gen/platformio.py -- the PlatformIO build generator
 #   - script/test_build_components.py -- the harness the job invokes
 #   - .github/workflows/ci.yml -- the job's own definition
-# Shared by every toolchain smoke-test job: the harness it invokes and the
-# workflow that defines it
-_SMOKE_HARNESS_TRIGGER_FILES = frozenset(
+ESP32_PLATFORMIO_TRIGGER_FILES = frozenset(
     {
+        "esphome/build_gen/platformio.py",
         "script/test_build_components.py",
         ".github/workflows/ci.yml",
     }
 )
 
-ESP32_PLATFORMIO_TRIGGER_FILES = _SMOKE_HARNESS_TRIGGER_FILES | {
-    "esphome/build_gen/platformio.py",
-}
-
-
-def _path_or_file_trigger(
-    files: list[str],
-    trigger_files: frozenset[str],
-    trigger_prefixes: tuple[str, ...],
-) -> bool:
-    """Whether any changed file matches the given infrastructure triggers."""
-    return any(
-        file in trigger_files or file.startswith(trigger_prefixes) for file in files
-    )
-
-
-@cache
-def _cached_components_closure(files: tuple[str, ...]) -> frozenset[str]:
-    """Dependency closure of the changed components, from the changed files.
-
-    The walk is expensive and every toolchain smoke-test job asks for the
-    same file list, so compute it once per run."""
-    component_files = [f for f in files if filter_component_and_test_files(f)]
-    return frozenset(get_components_with_dependencies(component_files, True))
-
 
 def _esp32_platformio_path_or_file_trigger(files: list[str]) -> bool:
     """Whether any changed file is a PlatformIO infrastructure / harness trigger."""
-    return _path_or_file_trigger(
-        files, ESP32_PLATFORMIO_TRIGGER_FILES, ESP32_PLATFORMIO_TRIGGER_PATH_PREFIXES
-    )
+    for file in files:
+        if file in ESP32_PLATFORMIO_TRIGGER_FILES:
+            return True
+        if any(
+            file.startswith(prefix) for prefix in ESP32_PLATFORMIO_TRIGGER_PATH_PREFIXES
+        ):
+            return True
+    return False
 
 
 def _esp_idf_infra_changed(files: list[str]) -> bool:
     """Whether any changed file is ESP-IDF build/runner infrastructure."""
-    return _path_or_file_trigger(
-        files, ESP_IDF_INFRA_TRIGGER_FILES, ESP_IDF_INFRA_TRIGGER_PATH_PREFIXES
-    )
+    for file in files:
+        if file in ESP_IDF_INFRA_TRIGGER_FILES:
+            return True
+        if any(
+            file.startswith(prefix) for prefix in ESP_IDF_INFRA_TRIGGER_PATH_PREFIXES
+        ):
+            return True
+    return False
 
 
 def esp32_platformio_components_to_test(branch: str | None = None) -> list[str]:
@@ -616,23 +599,15 @@ def esp32_platformio_components_to_test(branch: str | None = None) -> list[str]:
     Returns:
         Sorted list of component names to compile.
     """
-    return _toolchain_components_to_test(
-        branch, ESP32_PLATFORMIO_TEST_COMPONENTS, _esp32_platformio_path_or_file_trigger
-    )
-
-
-def _toolchain_components_to_test(
-    branch: str | None,
-    test_set: frozenset[str],
-    infra_trigger: Callable[[list[str]], bool],
-) -> list[str]:
-    """The shared narrowing rule for the per-toolchain smoke-test jobs."""
     files = changed_files(branch)
 
-    if core_changed(files) or infra_trigger(files):
-        return sorted(test_set)
+    if core_changed(files) or _esp32_platformio_path_or_file_trigger(files):
+        return sorted(ESP32_PLATFORMIO_TEST_COMPONENTS)
 
-    return sorted(test_set & _cached_components_closure(tuple(files)))
+    component_files = [f for f in files if filter_component_and_test_files(f)]
+    changed = get_components_with_dependencies(component_files, True)
+
+    return sorted(ESP32_PLATFORMIO_TEST_COMPONENTS & set(changed))
 
 
 def should_run_esp32_platformio(branch: str | None = None) -> bool:
@@ -653,83 +628,6 @@ def should_run_esp32_platformio(branch: str | None = None) -> bool:
     return bool(esp32_platformio_components_to_test(branch))
 
 
-# The `--toolchain arduino` smoke-test set: covers the core, the bundled and
-# converted registry libraries, and the waveform path.
-ESP8266_NATIVE_TEST_COMPONENTS = frozenset(
-    {
-        "esp8266",
-        "api",
-        "web_server",
-        "captive_portal",
-        "mqtt",
-        "esp8266_pwm",
-        "neopixelbus",
-        "bme280_i2c",
-        "uart",
-    }
-)
-
-# Infrastructure whose changes always trigger the native ESP8266 compile
-# test. esphome/build_helpers/ holds the idedata and size-summary helpers
-# the backend shares with the native ESP-IDF build.
-ESP8266_NATIVE_TRIGGER_PATH_PREFIXES = (
-    "esphome/arduino8266/",
-    "esphome/arduino/",
-    "esphome/build_helpers/",
-)
-# Shared library-conversion modules every native build imports; espidf-only
-# infra (build_gen/espidf.py) deliberately stays out of the esp8266 set.
-_NATIVE_SHARED_TRIGGER_FILES = frozenset(
-    {
-        "esphome/framework_helpers.py",
-        "esphome/platformio/library.py",
-        "esphome/platformio/extra_script.py",
-    }
-)
-# Tripwire: the shared modules must stay in the ESP-IDF trigger set too
-# (now defined in clang_tidy_hash), or its smoke test silently skips them
-assert _NATIVE_SHARED_TRIGGER_FILES <= ESP_IDF_INFRA_TRIGGER_FILES
-ESP8266_NATIVE_TRIGGER_FILES = (
-    _NATIVE_SHARED_TRIGGER_FILES
-    | _SMOKE_HARNESS_TRIGGER_FILES
-    | {
-        "esphome/build_gen/arduino8266.py",
-        "esphome/build_gen/build_tool.py",
-        "esphome/components/esp8266/build_surgery.py",
-        "esphome/components/esp8266/boards.py",
-        "esphome/platformio/registry.py",
-        # esp8266/__init__.py imports copy_ccache_script from it
-        "esphome/platformio/toolchain.py",
-        ".github/actions/cache-arduino8266/action.yml",
-    }
-)
-
-
-def _esp8266_native_path_or_file_trigger(files: list[str]) -> bool:
-    """Whether any changed file is native-ESP8266 infrastructure / harness."""
-    # base_python_changed covers the top-level esphome/*.py modules the
-    # native backend imports directly (framework_helpers, helpers, writer,
-    # __main__); without it a change there would silently skip this job.
-    # base_python_changed is deliberately broad (any top-level esphome/*.py)
-    # as belt-and-braces while the backend is new; narrow it to the modules
-    # the backend imports once the toolchain has soaked a few releases
-    return base_python_changed(files) or _path_or_file_trigger(
-        files, ESP8266_NATIVE_TRIGGER_FILES, ESP8266_NATIVE_TRIGGER_PATH_PREFIXES
-    )
-
-
-def esp8266_native_components_to_test(branch: str | None = None) -> list[str]:
-    """Subset of ``ESP8266_NATIVE_TEST_COMPONENTS`` the job needs to compile.
-
-    Same narrowing logic as ``esp32_platformio_components_to_test``: the full
-    list on core or infrastructure changes, otherwise the intersection with
-    the changed-component dependency closure (empty list skips the job).
-    """
-    return _toolchain_components_to_test(
-        branch, ESP8266_NATIVE_TEST_COMPONENTS, _esp8266_native_path_or_file_trigger
-    )
-
-
 def determine_cpp_unit_tests(
     branch: str | None = None,
 ) -> tuple[bool, list[str]]:
@@ -1328,8 +1226,6 @@ def main() -> None:
         run_device_builder = True
         esp32_platformio_components = sorted(ESP32_PLATFORMIO_TEST_COMPONENTS)
         run_esp32_platformio = True
-        esp8266_native_components = sorted(ESP8266_NATIVE_TEST_COMPONENTS)
-        run_esp8266_native = True
     else:
         integration_run_all, integration_test_files = determine_integration_tests(
             args.branch
@@ -1341,8 +1237,6 @@ def main() -> None:
         run_device_builder = should_run_device_builder(args.branch)
         esp32_platformio_components = esp32_platformio_components_to_test(args.branch)
         run_esp32_platformio = bool(esp32_platformio_components)
-        esp8266_native_components = esp8266_native_components_to_test(args.branch)
-        run_esp8266_native = bool(esp8266_native_components)
     run_integration, integration_test_buckets = _compute_integration_test_buckets(
         integration_run_all, integration_test_files
     )
@@ -1538,8 +1432,6 @@ def main() -> None:
         "device_builder": run_device_builder,
         "esp32_platformio": run_esp32_platformio,
         "esp32_platformio_components": ",".join(esp32_platformio_components),
-        "esp8266_native": run_esp8266_native,
-        "esp8266_native_components": ",".join(esp8266_native_components),
         "changed_components": changed_components,
         "changed_components_with_tests": changed_components_with_tests,
         "directly_changed_components_with_tests": list(directly_changed_with_tests),

script/test_build_components.py

@@ -1027,7 +1027,6 @@ def test_components(
     isolated_components: set[str] | None = None,
     base_only: bool = False,
     toolchain: str | None = None,
-    fail_on_no_tests: bool = False,
 ) -> int:
     """Test components with optional intelligent grouping.
 
@@ -1062,34 +1061,20 @@ def test_components(
     # toolchain build.
     include_validate = esphome_command != "compile"
 
-    # Find all component tests; remember which components each pattern
-    # (wildcards included) matched, for the deferred no-tests accounting
+    # Find all component tests
     all_tests = {}
-    pattern_components: dict[str, set[str]] = {}
     for pattern in component_patterns:
         # Skip empty patterns (happens when components list is empty string)
         if not pattern:
             continue
-        found = find_component_tests(
-            tests_dir, pattern, base_only, include_validate=include_validate
+        all_tests.update(
+            find_component_tests(
+                tests_dir, pattern, base_only, include_validate=include_validate
+            )
         )
-        pattern_components[pattern] = set(found)
-        all_tests.update(found)
-
-    # The flag's contract is "no test matched fails": a fully blank pattern
-    # list would otherwise slide into the reference-baseline fallback and
-    # exit green while building nothing a caller asked for
-    if fail_on_no_tests and not any(component_patterns):
-        print("No components requested (blank component list)")
-        return 1
-
-    if fail_on_no_tests and not all_tests:
-        # Nothing matched at all: fail before the synthetic baseline build,
-        # which would spend a compile reporting success on nothing. Partial
-        # matches defer to the per-pattern accounting after the summary.
-        print(f"No components found matching: {component_patterns}")
-        return 1
 
+    # If no components found, build a reference configuration for baseline comparison
+    # Create a synthetic "empty" component test that will build just the base config
     if not all_tests:
         print(f"No components found matching: {component_patterns}")
         print(
@@ -1193,26 +1178,6 @@ def test_components(
                         toolchain=toolchain,
                     )
 
-    silent: list[str] = []
-    if fail_on_no_tests:
-        # A green run that built nothing for a requested pattern (renamed
-        # fixture, missing base file, version-suffix mismatch, a wildcard
-        # matching no component) must not pass CI. Per pattern: an
-        # all-or-nothing check would let one silent pattern hide behind the
-        # others. Opt-in: some legs (the esp32-ard smoke subset)
-        # legitimately match nothing. Failing is deferred past the summary
-        # so a real failure's reproduce commands still print.
-        built = {c for r in test_results for c in r.components}
-        # A pattern is silent when it matched no fixture, or when none of
-        # its matched components produced a build (wildcards included)
-        silent = [
-            p
-            for p in component_patterns
-            if p and not (pattern_components.get(p, set()) & built)
-        ]
-        if silent:
-            print(f"No tests ran for requested pattern(s): {', '.join(silent)}")
-
     # Separate results into passed and failed
     passed_results = [r for r in test_results if r.success]
     failed_results = [r for r in test_results if not r.success]
@@ -1244,7 +1209,7 @@ def test_components(
     if os.environ.get("GITHUB_STEP_SUMMARY"):
         write_github_summary(test_results, toolchain=toolchain)
 
-    if failed_results or silent:
+    if failed_results:
         return 1
 
     return 0
@@ -1299,12 +1264,6 @@ def main() -> int:
         "--toolchain",
         help="Select toolchain for compiling.",
     )
-    parser.add_argument(
-        "--fail-on-no-tests",
-        action="store_true",
-        help="Exit non-zero when no test matched (for CI legs whose "
-        "components must all have fixtures)",
-    )
 
     args = parser.parse_args()
 
@@ -1323,7 +1282,6 @@ def main() -> int:
         continue_on_fail=args.continue_on_fail,
         enable_grouping=not args.no_grouping,
         isolated_components=isolated_components,
-        fail_on_no_tests=args.fail_on_no_tests,
         base_only=args.base_only,
         toolchain=args.toolchain,
     )

tests/benchmarks/stubs/esphome/components/serial_proxy/serial_proxy.h

@@ -40,6 +40,9 @@ class SerialProxy {
     return SerialProxyResult::SERIAL_PROXY_RESULT_OK;
   }
   void write_from_client(api::APIConnection *api_connection, const uint8_t *data, size_t len) {}
+  SerialProxyResult set_mode_from_client(api::APIConnection *api_connection, api::enums::SerialProxyMode mode) {
+    return SerialProxyResult::SERIAL_PROXY_RESULT_OK;
+  }
   SerialProxyResult set_modem_pins(api::APIConnection *api_connection, uint32_t line_states) {
     return SerialProxyResult::SERIAL_PROXY_RESULT_OK;
   }

tests/components/serial_proxy/test-tap.esp32-idf.yaml

@@ -0,0 +1,14 @@
+substitutions:
+  tx_pin: GPIO4
+  rx_pin: GPIO5
+
+# Compile the tap code paths; no tap is attached, so this exercises the
+# null-tap branches that a normal build never defines.
+esphome:
+  platformio_options:
+    build_flags:
+      - "-DUSE_SERIAL_PROXY_TAP"
+
+packages:
+  uart: !include ../../test_build_components/common/uart/esp32-idf.yaml
+  serial_proxy: !include common.yaml

tests/components/serial_proxy/test-usb.esp32-s3-idf.yaml

@@ -0,0 +1,21 @@
+wifi:
+  ssid: MySSID
+  password: password1
+
+api:
+
+usb_host:
+
+# port_type is omitted deliberately: a port on a USB UART channel derives USB_SERIAL
+usb_uart:
+  - type: CDC_ACM
+    vid: 0x303A
+    pid: 0x831A
+    channels:
+      - id: usb_serial_channel
+        baud_rate: 460800
+
+serial_proxy:
+  - id: serial_proxy_usb
+    uart_id: usb_serial_channel
+    name: USB Serial Port

tests/components/zigbee_proxy/.gitignore

@@ -0,0 +1,5 @@
+# Gitignore settings for ESPHome
+# This is an example and may include too much for your use-case.
+# You can modify this file to suit your needs.
+/.esphome/
+/secrets.yaml

tests/components/zigbee_proxy/common.yaml

@@ -0,0 +1,22 @@
+esphome:
+  name: test
+
+wifi:
+  ssid: test
+  password: password
+  power_save_mode: none
+
+api:
+
+uart:
+  - id: zigbee_uart
+    tx_pin: ${tx_pin}
+    rx_pin: ${rx_pin}
+    baud_rate: 115200
+
+# The port owns the UART and carries every byte; zigbee_proxy only taps it
+serial_proxy:
+  - id: zigbee_serial
+    uart_id: zigbee_uart
+    name: Zigbee
+    port_type: TTL

tests/components/zigbee_proxy/test-usb.esp32-s3-idf.yaml

@@ -0,0 +1,26 @@
+wifi:
+  ssid: test
+  password: password
+  power_save_mode: none
+
+api:
+
+usb_host:
+
+usb_uart:
+  - type: CDC_ACM
+    vid: 0x303A
+    pid: 0x831A
+    channels:
+      - id: zigbee_usb_channel
+        baud_rate: 460800
+
+# The tapped port may be a USB CDC ACM channel just as well as a hardware UART:
+# zigbee_proxy never touches the UART itself, so it does not care which it is.
+serial_proxy:
+  - id: zigbee_usb_serial
+    uart_id: zigbee_usb_channel
+    name: Zigbee
+
+zigbee_proxy:
+  serial_proxy_id: zigbee_usb_serial

tests/components/zigbee_proxy/test.esp32-idf.yaml

@@ -0,0 +1,15 @@
+substitutions:
+  tx_pin: GPIO17
+  rx_pin: GPIO16
+
+esp32:
+  board: esp32dev
+
+<<: !include common.yaml
+
+zigbee_proxy:
+  serial_proxy_id: zigbee_serial
+  buffer_size: 1024
+  initial_timeout: 1600
+  min_timeout: 400
+  max_timeout: 3200

tests/components/zigbee_proxy/test.esp8266-ard.yaml

@@ -0,0 +1,12 @@
+substitutions:
+  tx_pin: GPIO1
+  rx_pin: GPIO3
+
+esp8266:
+  board: nodemcuv2
+
+<<: !include common.yaml
+
+zigbee_proxy:
+  serial_proxy_id: zigbee_serial
+  buffer_size: 512

tests/components/zigbee_proxy/test.rp2040-ard.yaml

@@ -0,0 +1,8 @@
+substitutions:
+  tx_pin: GPIO0
+  rx_pin: GPIO1
+
+<<: !include common.yaml
+
+zigbee_proxy:
+  serial_proxy_id: zigbee_serial

tests/script/test_determine_jobs.py

@@ -78,17 +78,6 @@ def mock_esp32_platformio_components_to_test() -> Generator[Mock, None, None]:
         yield mock
 
 
-@pytest.fixture
-def mock_esp8266_native_components_to_test() -> Generator[Mock, None, None]:
-    """Mock esp8266_native_components_to_test from determine_jobs.
-
-    main() drives both the ``esp8266_native`` boolean output and the
-    ``esp8266_native_components`` CSV from this one function.
-    """
-    with patch.object(determine_jobs, "esp8266_native_components_to_test") as mock:
-        yield mock
-
-
 @pytest.fixture
 def mock_determine_cpp_unit_tests() -> Generator[Mock, None, None]:
     """Mock determine_cpp_unit_tests from helpers."""
@@ -117,7 +106,6 @@ def clear_determine_jobs_caches() -> None:
     """Clear all cached functions before each test."""
     determine_jobs._is_clang_tidy_full_scan.cache_clear()
     determine_jobs._component_has_tests.cache_clear()
-    determine_jobs._cached_components_closure.cache_clear()
 
 
 def test_main_all_tests_should_run(
@@ -128,7 +116,6 @@ def test_main_all_tests_should_run(
     mock_should_run_import_time: Mock,
     mock_should_run_device_builder: Mock,
     mock_esp32_platformio_components_to_test: Mock,
-    mock_esp8266_native_components_to_test: Mock,
     mock_changed_files: Mock,
     mock_determine_cpp_unit_tests: Mock,
     capsys: pytest.CaptureFixture[str],
@@ -145,7 +132,6 @@ def test_main_all_tests_should_run(
     mock_should_run_import_time.return_value = True
     mock_should_run_device_builder.return_value = True
     mock_esp32_platformio_components_to_test.return_value = ["api", "esp32"]
-    mock_esp8266_native_components_to_test.return_value = ["api", "logger"]
     mock_determine_cpp_unit_tests.return_value = (False, ["wifi", "api", "sensor"])
 
     # Mock changed_files to return non-component files (to avoid memory impact)
@@ -222,8 +208,6 @@ def test_main_all_tests_should_run(
     assert output["device_builder"] is True
     assert output["esp32_platformio"] is True
     assert output["esp32_platformio_components"] == "api,esp32"
-    assert output["esp8266_native"] is True
-    assert output["esp8266_native_components"] == "api,logger"
     assert output["changed_components"] == ["wifi", "api", "sensor"]
     # changed_components_with_tests will only include components that actually have test files
     assert "changed_components_with_tests" in output
@@ -260,7 +244,6 @@ def test_main_no_tests_should_run(
     mock_should_run_import_time: Mock,
     mock_should_run_device_builder: Mock,
     mock_esp32_platformio_components_to_test: Mock,
-    mock_esp8266_native_components_to_test: Mock,
     mock_changed_files: Mock,
     mock_determine_cpp_unit_tests: Mock,
     capsys: pytest.CaptureFixture[str],
@@ -277,7 +260,6 @@ def test_main_no_tests_should_run(
     mock_should_run_import_time.return_value = False
     mock_should_run_device_builder.return_value = False
     mock_esp32_platformio_components_to_test.return_value = []
-    mock_esp8266_native_components_to_test.return_value = []
     mock_determine_cpp_unit_tests.return_value = (False, [])
 
     # Mock changed_files to return no component files
@@ -320,8 +302,6 @@ def test_main_no_tests_should_run(
     assert output["device_builder"] is False
     assert output["esp32_platformio"] is False
     assert output["esp32_platformio_components"] == ""
-    assert output["esp8266_native"] is False
-    assert output["esp8266_native_components"] == ""
     assert output["changed_components"] == []
     assert output["changed_components_with_tests"] == []
     assert output["component_test_count"] == 0
@@ -3171,78 +3151,6 @@ def test_memory_impact_elf_layouts_are_found(tmp_path: Path) -> None:
         assert find_elf_path(build_path) == elf, f"{platform} ELF not found"
 
 
-@pytest.mark.parametrize(
-    "changed",
-    [
-        "esphome/arduino8266/framework.py",
-        "esphome/build_gen/arduino8266.py",
-        "esphome/components/esp8266/build_surgery.py",
-        # Shared modules the native build depends on
-        "esphome/build_helpers/idedata.py",
-        "esphome/platformio/library.py",
-        # Top-level esphome/*.py modules the backend imports directly
-        "esphome/framework_helpers.py",
-        "esphome/writer.py",
-        # esp8266/__init__.py imports copy_ccache_script from it
-        "esphome/platformio/toolchain.py",
-        # The composite cache action must not ship unexercised
-        ".github/actions/cache-arduino8266/action.yml",
-    ],
-)
-def test_esp8266_native_components_full_list_on_infra_change(changed: str) -> None:
-    """Native-ESP8266 infrastructure changes run the full test list."""
-    with (
-        patch.object(determine_jobs, "changed_files", return_value=[changed]),
-        patch.object(
-            determine_jobs,
-            "get_components_with_dependencies",
-            return_value=["wifi"],
-        ),
-    ):
-        result = determine_jobs.esp8266_native_components_to_test()
-        assert result == sorted(determine_jobs.ESP8266_NATIVE_TEST_COMPONENTS)
-
-
-@pytest.mark.parametrize(
-    ("changed_files", "dependency_closure", "expected"),
-    [
-        # Tested component changed -- narrow to the intersection.
-        (
-            ["esphome/components/mqtt/mqtt_client.cpp"],
-            ["mqtt", "json"],
-            ["mqtt"],
-        ),
-        # Components outside the test set return an empty list (job skipped).
-        (
-            ["esphome/components/wifi/wifi_component.cpp"],
-            ["wifi", "network"],
-            [],
-        ),
-        # espidf infrastructure is not an esp8266-native trigger; the
-        # native backend depends on esphome/build_helpers/ instead.
-        (["esphome/build_gen/espidf.py"], [], []),
-        (["esphome/espidf/toolchain.py"], [], []),
-        (["README.md"], [], []),
-    ],
-)
-def test_esp8266_native_components_to_test_narrowing(
-    changed_files: list[str],
-    dependency_closure: list[str],
-    expected: list[str],
-) -> None:
-    """Component changes narrow the native-ESP8266 test list."""
-    with (
-        patch.object(determine_jobs, "changed_files", return_value=changed_files),
-        patch.object(
-            determine_jobs,
-            "get_components_with_dependencies",
-            return_value=dependency_closure,
-        ),
-    ):
-        result = determine_jobs.esp8266_native_components_to_test()
-        assert result == expected
-
-
 def test_compute_integration_test_buckets_no_durations_full_fanout() -> None:
     """Without recorded durations the fan-out stays at the maximum."""
     files = [f"tests/integration/test_{i:03d}.py" for i in range(15)]

tests/script/test_test_build_components.py

@@ -236,98 +236,3 @@ def test_run_grouped_test_closes_group_when_subprocess_raises(
         )
 
     assert "::endgroup::" in capsys.readouterr().out
-
-
-def test_components_empty_match_fails_with_flag(
-    capsys: pytest.CaptureFixture[str],
-) -> None:
-    """Under --fail-on-no-tests, a real component filtered to a platform
-    with no matching test file must not pass CI as a green zero-component
-    compile."""
-    rc = tbc.test_components(
-        ["logger"],
-        "zz-none",
-        "compile",
-        False,
-        enable_grouping=False,
-        fail_on_no_tests=True,
-    )
-    assert rc == 1
-    assert "No tests ran for requested pattern(s): logger" in (capsys.readouterr().out)
-
-
-def test_components_component_with_no_base_file_fails_with_flag(
-    capsys: pytest.CaptureFixture[str],
-    monkeypatch: pytest.MonkeyPatch,
-) -> None:
-    """A component whose fixture matches the platform but whose platform has
-    no base file builds nothing; under the flag that silent zero fails by
-    component name instead of hiding behind other components."""
-    monkeypatch.setattr(tbc, "get_platform_base_files", lambda base_dir: {})
-    rc = tbc.test_components(
-        ["logger"],
-        "esp8266-ard",
-        "compile",
-        False,
-        enable_grouping=False,
-        fail_on_no_tests=True,
-    )
-    assert rc == 1
-    assert "No tests ran for requested pattern(s): logger" in (capsys.readouterr().out)
-
-
-def test_components_blank_list_fails_with_flag(
-    capsys: pytest.CaptureFixture[str],
-) -> None:
-    """A fully blank component list must not slide into the baseline
-    fallback and exit green under the flag."""
-    rc = tbc.test_components(
-        [""], "esp8266-ard", "compile", False, fail_on_no_tests=True
-    )
-    assert rc == 1
-    assert "blank component list" in capsys.readouterr().out
-
-
-def test_components_wildcard_no_match_fails_with_flag(
-    capsys: pytest.CaptureFixture[str],
-) -> None:
-    """A wildcard matching nothing must not degrade to the synthetic
-    baseline build and exit green under the flag."""
-    rc = tbc.test_components(
-        ["zz_no_such*"],
-        "esp8266-ard",
-        "compile",
-        False,
-        enable_grouping=False,
-        fail_on_no_tests=True,
-    )
-    assert rc == 1
-    assert "No components found matching" in capsys.readouterr().out
-
-
-def test_components_empty_match_tolerated_without_flag() -> None:
-    """The esp32-ard smoke leg deliberately builds only the subset with a
-    matching fixture; without the flag an empty match stays green."""
-    assert (
-        tbc.test_components(
-            ["logger"], "zz-none", "compile", False, enable_grouping=False
-        )
-        == 0
-    )
-
-
-def test_components_unknown_component_fails_with_flag(
-    capsys: pytest.CaptureFixture[str],
-) -> None:
-    """A renamed smoke-test component must shrink coverage loudly, not fall
-    into the reference-baseline build."""
-    rc = tbc.test_components(
-        ["no_such_component_xyz"],
-        "esp8266-ard",
-        "compile",
-        False,
-        enable_grouping=False,
-        fail_on_no_tests=True,
-    )
-    assert rc == 1
-    assert "No components found matching" in capsys.readouterr().out

tests/unit_tests/build_gen/test_espidf.py

@@ -4,9 +4,7 @@ from __future__ import annotations
 
 import json
 import logging
-import os
 from pathlib import Path
-import subprocess
 from unittest.mock import patch
 
 import pytest
@@ -490,616 +488,3 @@ def test_get_component_cmakelists_no_compile_features() -> None:
         content = get_component_cmakelists()
 
     assert "target_compile_features" not in content
-
-
-@pytest.fixture(autouse=True)
-def _pch_default_on(monkeypatch: pytest.MonkeyPatch) -> None:
-    """Pin the knob so a developer's ESPHOME_PCH_ENABLE=0 cannot fail these."""
-    monkeypatch.setenv("ESPHOME_PCH_ENABLE", "1")
-
-
-def _make_pch_device(tmp_path: Path, name: str) -> Path:
-    """A device dir with the pch source headers and a stub compile_commands."""
-    from esphome.build_helpers.pch import PCH_DEFAULT_HEADERS
-
-    dev = tmp_path / name
-    for header in PCH_DEFAULT_HEADERS:
-        path = dev / "src" / header
-        path.parent.mkdir(parents=True, exist_ok=True)
-        path.write_text("")
-    # A real quoted include chain and a per-device-named sdkconfig with
-    # identical content: the closure and sdkconfig inputs must be exercised
-    (dev / "src" / "esphome" / "core" / "defines.h").write_text(
-        '#include "esphome/core/macros.h"\n'
-    )
-    (dev / "src" / "esphome" / "core" / "macros.h").write_text("#define M 1\n")
-    # Both spellings: tests patch CORE.name to "test" or to the device name
-    (dev / f"sdkconfig.{name}").write_text("CONFIG_X=y\n")
-    (dev / "sdkconfig.test").write_text("CONFIG_X=y\n")
-    build = dev / "build"
-    build.mkdir(exist_ok=True)
-    from esphome.build_helpers.pch import pch_header_text
-
-    (build / "esphome_pch.h").write_text(pch_header_text(PCH_DEFAULT_HEADERS))
-    # Native separators: mixed f-string paths break the src-prefix match
-    # on Windows
-    src_file = str(dev / "src" / "a.cpp")
-    (build / "compile_commands.json").write_text(
-        json.dumps(
-            [
-                {
-                    "directory": str(build),
-                    "command": (
-                        "g++ -DX=1 -include esphome_pch.h "
-                        "-o esp-idf/src/CMakeFiles/__idf_src.dir/a.cpp.obj "
-                        f'-c "{src_file}"'
-                    ),
-                    "file": src_file,
-                }
-            ]
-        )
-    )
-    return dev
-
-
-def test_prepare_pch_writes_header_and_sum(tmp_path: Path) -> None:
-    from esphome.build_gen.espidf import prepare_pch
-
-    dev = _make_pch_device(tmp_path, "dev_a")
-    CORE.build_path = dev
-    gch = dev / "build" / "esphome_pch.h.gch"
-
-    def fake_compile(cmd, **kwargs):
-        # The compile must target the header, not the stub TU
-        assert cmd[-5:-3] == ["c++-header", "-c"]
-        gch.write_bytes(b"gch")
-        return subprocess.CompletedProcess(cmd, 0, "", "")
-
-    with (
-        patch.object(CORE, "name", "test"),
-        patch("esphome.build_helpers.pch.subprocess.run", side_effect=fake_compile),
-    ):
-        prepare_pch()
-    checksum = (dev / "build" / "esphome_pch.h.gch.sum").read_text().strip()
-    assert len(checksum) == 64
-    # Unchanged inputs: the second call must not recompile
-    with (
-        patch.object(CORE, "name", "test"),
-        patch("esphome.build_helpers.pch.subprocess.run", side_effect=AssertionError),
-    ):
-        prepare_pch()
-
-
-def test_pch_no_device_path_poison(tmp_path: Path) -> None:
-    """Regression: neither the injected -include nor the .sum may carry the
-    per-device build path, or cross-device ccache sharing breaks."""
-    from esphome.build_gen.espidf import get_component_cmakelists, prepare_pch
-
-    sums = []
-    for name in ("dev_a", "dev_b"):
-        dev = _make_pch_device(tmp_path, name)
-        CORE.build_path = dev
-        gch = dev / "build" / "esphome_pch.h.gch"
-
-        def fake_compile(cmd, _gch=gch, **kwargs):
-            _gch.write_bytes(b"gch")
-            return subprocess.CompletedProcess(cmd, 0, "", "")
-
-        with (
-            patch.object(CORE, "name", name),
-            patch("esphome.build_helpers.pch.subprocess.run", side_effect=fake_compile),
-        ):
-            prepare_pch()
-            content = get_component_cmakelists()
-        assert str(dev) not in content
-        sums.append((dev / "build" / "esphome_pch.h.gch.sum").read_text())
-    assert sums[0] == sums[1]
-
-
-def test_component_cmakelists_pch_block(monkeypatch: pytest.MonkeyPatch) -> None:
-    from esphome.build_gen.espidf import get_component_cmakelists
-
-    content = get_component_cmakelists()
-    assert '"$<$<COMPILE_LANGUAGE:CXX>:-include>"' in content
-    assert '"$<$<COMPILE_LANGUAGE:CXX>:esphome_pch.h>"' in content
-    monkeypatch.setenv("ESPHOME_PCH_ENABLE", "0")
-    assert "-include" not in get_component_cmakelists()
-
-
-def test_pch_compile_command_variants(tmp_path: Path) -> None:
-    """Missing DB, no matching entry, and launcher-prefixed commands."""
-    from esphome.build_helpers.pch import pch_compile_command
-
-    build = tmp_path / "build"
-    build.mkdir()
-    header = build / "esphome_pch.h"
-    gch = build / "esphome_pch.h.gch"
-    assert pch_compile_command(build, header, gch) is None
-
-    (build / "compile_commands.json").write_text(
-        json.dumps(
-            [
-                {"command": "gcc -c other.c", "file": "other.c"},
-            ]
-        )
-    )
-    assert pch_compile_command(build, header, gch) is None
-
-    src_file = str(tmp_path / "src" / "esphome" / "a.cpp")
-    (build / "compile_commands.json").write_text(
-        json.dumps(
-            [
-                {
-                    "command": (
-                        "/usr/bin/ccache g++ -DX=1 -include esphome_pch.h -MMD "
-                        "-MT a.cpp.obj -MF a.cpp.obj.d "
-                        "-o esp-idf/src/CMakeFiles/__idf_src.dir/a.cpp.obj "
-                        f"-c {src_file}"
-                    ),
-                    "file": src_file,
-                },
-            ]
-        )
-    )
-    # Launcher stripped; -include/-o/-c and depfile flags removed
-    cmd, cmd_dir = pch_compile_command(build, header, gch)
-    assert cmd == [
-        "g++",
-        "-DX=1",
-        "-x",
-        "c++-header",
-        "-c",
-        str(header),
-        "-o",
-        str(gch),
-    ]
-    # The compile must run where the flags were resolved
-    assert cmd_dir == build
-
-
-@pytest.mark.skipif(os.name == "nt", reason="symlinks need privileges on Windows")
-def test_pch_compile_command_matches_src_through_symlink(tmp_path: Path) -> None:
-    """Find the src TU when CMake spells paths through a different symlink (macOS /tmp)."""
-    from esphome.build_helpers.pch import pch_compile_command
-
-    real = tmp_path / "real"
-    (real / "src" / "esphome").mkdir(parents=True)
-    link = tmp_path / "link"
-    link.symlink_to(real, target_is_directory=True)
-    CORE.build_path = str(real)
-    build = real / "build"
-    build.mkdir()
-    header = build / "esphome_pch.h"
-    gch = build / "esphome_pch.h.gch"
-    src_file = str(link / "src" / "esphome" / "a.cpp")
-    (build / "compile_commands.json").write_text(
-        json.dumps([{"command": f"g++ -DX=1 -o a.obj -c {src_file}", "file": src_file}])
-    )
-
-    cmd, cmd_dir = pch_compile_command(build, header, gch)
-
-    assert cmd[:2] == ["g++", "-DX=1"]
-    assert cmd_dir == build
-
-
-def test_pch_compile_command_rejects_unusable_entries(tmp_path: Path) -> None:
-    """Malformed DB shapes and command-less entries skip cleanly instead of
-    producing a compiler-less argv retried every build."""
-    from esphome.build_helpers.pch import pch_compile_command
-
-    build = tmp_path / "build"
-    build.mkdir()
-    header = build / "esphome_pch.h"
-    gch = build / "esphome_pch.h.gch"
-    db = build / "compile_commands.json"
-    src_file = str(tmp_path / "src" / "esphome" / "a.cpp")
-
-    db.write_text(json.dumps({"not": "a list"}))
-    assert pch_compile_command(build, header, gch) is None
-
-    db.write_text(json.dumps(["just a string"]))
-    assert pch_compile_command(build, header, gch) is None
-
-    # An empty-string directory must fall back to the build dir, not cwd
-    db.write_text(
-        json.dumps(
-            [
-                {
-                    "directory": "",
-                    "command": f"g++ -DX=1 -o a.obj -c {src_file}",
-                    "file": src_file,
-                }
-            ]
-        )
-    )
-    _, cmd_dir = pch_compile_command(build, header, gch)
-    assert cmd_dir == build
-
-    # Corrupted entries with null fields must skip, not raise
-    db.write_text(
-        json.dumps(
-            [
-                {"file": None, "command": "g++ -c x.cpp", "directory": None},
-                {"file": src_file, "command": None, "directory": None},
-            ]
-        )
-    )
-    assert pch_compile_command(build, header, gch) is None
-
-    # arguments-style entry (allowed by the spec, unused by CMake)
-    db.write_text(
-        json.dumps([{"arguments": ["g++", "-c", src_file], "file": src_file}])
-    )
-    assert pch_compile_command(build, header, gch) is None
-
-
-def test_pch_header_list_order_is_in_checksum(
-    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
-) -> None:
-    """Reordering PCH_DEFAULT_HEADERS keeps the include closure identical, but the
-    generated header text differs, so the .gch must rebuild."""
-    import esphome.build_gen.espidf as espidf_mod
-
-    dev = _make_pch_device(tmp_path, "dev_r")
-    CORE.build_path = dev
-    gch = dev / "build" / "esphome_pch.h.gch"
-
-    def fake_compile(cmd, **kwargs):
-        gch.write_bytes(b"gch")
-        return subprocess.CompletedProcess(cmd, 0, "", "")
-
-    with (
-        patch.object(CORE, "name", "test"),
-        patch("esphome.build_helpers.pch.subprocess.run", side_effect=fake_compile),
-    ):
-        espidf_mod.prepare_pch()
-        first = (dev / "build" / "esphome_pch.h.gch.sum").read_text()
-        monkeypatch.setattr(
-            espidf_mod,
-            "PCH_DEFAULT_HEADERS",
-            tuple(reversed(espidf_mod.PCH_DEFAULT_HEADERS)),
-        )
-        espidf_mod.prepare_pch()
-    assert (dev / "build" / "esphome_pch.h.gch.sum").read_text() != first
-
-
-def test_prepare_pch_failure_writes_marker_and_skips_retry(tmp_path: Path) -> None:
-    from esphome.build_gen.espidf import prepare_pch
-
-    dev = _make_pch_device(tmp_path, "dev_f")
-    CORE.build_path = dev
-    calls = []
-
-    def failing_compile(cmd, **kwargs):
-        calls.append(cmd)
-        return subprocess.CompletedProcess(cmd, 1, "", "boom")
-
-    with (
-        patch.object(CORE, "name", "test"),
-        patch("esphome.build_helpers.pch.subprocess.run", side_effect=failing_compile),
-    ):
-        prepare_pch()
-        prepare_pch()
-    assert len(calls) == 1
-    assert not (dev / "build" / "esphome_pch.h.gch.sum").exists()
-    assert (dev / "build" / "esphome_pch.h.gch.failed").exists()
-
-
-def test_prepare_pch_spawn_oserror_is_transient(tmp_path: Path) -> None:
-    """Spawn/IO failures retry on the next build instead of latching."""
-    from esphome.build_gen.espidf import prepare_pch
-
-    dev = _make_pch_device(tmp_path, "dev_o")
-    CORE.build_path = dev
-    calls = []
-
-    def raising(cmd, **kwargs):
-        calls.append(cmd)
-        raise OSError("no such compiler")
-
-    header = dev / "build" / "esphome_pch.h"
-    before = header.stat().st_mtime_ns
-    with (
-        patch.object(CORE, "name", "test"),
-        patch("esphome.build_helpers.pch.subprocess.run", side_effect=raising),
-    ):
-        prepare_pch()
-        prepare_pch()
-    assert not (dev / "build" / "esphome_pch.h.gch.failed").exists()
-    assert not (dev / "build" / "esphome_pch.h.gch.sum").exists()
-    assert len(calls) == 2
-    # No .gch was ever in play, so the header must not be re-touched into
-    # forcing a full rebuild on every failing build
-    assert header.stat().st_mtime_ns == before
-
-
-def test_prepare_pch_transient_with_stale_gch_bumps_header(tmp_path: Path) -> None:
-    """A stale .gch removed on a transient failure must dirty its consumers."""
-    from esphome.build_gen.espidf import prepare_pch
-
-    dev = _make_pch_device(tmp_path, "dev_s")
-    CORE.build_path = dev
-    gch = dev / "build" / "esphome_pch.h.gch"
-    gch.write_bytes(b"stale")
-    header = dev / "build" / "esphome_pch.h"
-    os.utime(header, (1, 1))
-    with (
-        patch.object(CORE, "name", "test"),
-        patch(
-            "esphome.build_helpers.pch.subprocess.run",
-            side_effect=OSError("no such compiler"),
-        ),
-    ):
-        prepare_pch()
-    assert not gch.exists()
-    assert header.stat().st_mtime_ns > 1_000_000_000
-
-
-def test_prepare_pch_disabled_discards_and_skips_compile(
-    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
-) -> None:
-    """The escape hatch is self-cleaning: a leftover .gch is removed."""
-    from esphome.build_gen.espidf import prepare_pch
-
-    monkeypatch.setenv("ESPHOME_PCH_ENABLE", "0")
-    dev = _make_pch_device(tmp_path, "dev_d")
-    CORE.build_path = dev
-    stale = dev / "build" / "esphome_pch.h.gch"
-    stale.write_bytes(b"stale")
-    with patch("esphome.build_helpers.pch.subprocess.run", side_effect=AssertionError):
-        prepare_pch()
-    assert not stale.exists()
-
-
-def test_prepare_pch_missing_sdkconfig_fails_closed(tmp_path: Path) -> None:
-    """No sdkconfig means no config identity for the .sum: no pch at all."""
-    from esphome.build_gen.espidf import prepare_pch
-
-    dev = _make_pch_device(tmp_path, "dev_m")
-    (dev / "sdkconfig.test").unlink()
-    CORE.build_path = dev
-    stale = dev / "build" / "esphome_pch.h.gch"
-    stale.write_bytes(b"stale")
-    with (
-        patch.object(CORE, "name", "test"),
-        patch("esphome.build_helpers.pch.subprocess.run", side_effect=AssertionError),
-    ):
-        prepare_pch()
-    assert not stale.exists()
-    assert not (dev / "build" / "esphome_pch.h.gch.sum").exists()
-
-
-def test_prepare_pch_signal_kill_is_transient(tmp_path: Path) -> None:
-    """A signal-killed compile (OOM) must not latch the .failed marker."""
-    from esphome.build_gen.espidf import prepare_pch
-
-    dev = _make_pch_device(tmp_path, "dev_k")
-    CORE.build_path = dev
-    calls = []
-
-    def killed(cmd, **kwargs):
-        calls.append(cmd)
-        return subprocess.CompletedProcess(cmd, -9, "", "")
-
-    with (
-        patch.object(CORE, "name", "test"),
-        patch("esphome.build_helpers.pch.subprocess.run", side_effect=killed),
-    ):
-        prepare_pch()
-        prepare_pch()
-    assert not (dev / "build" / "esphome_pch.h.gch.failed").exists()
-    assert len(calls) == 2
-
-
-def test_prepare_pch_without_compile_commands(tmp_path: Path) -> None:
-    """Stale checksum but no configured TU yet: no compile, no sidecars."""
-    from esphome.build_gen.espidf import prepare_pch
-
-    dev = _make_pch_device(tmp_path, "dev_n")
-    (dev / "build" / "compile_commands.json").unlink()
-    CORE.build_path = dev
-    with (
-        patch.object(CORE, "name", "test"),
-        patch("esphome.build_helpers.pch.subprocess.run", side_effect=AssertionError),
-    ):
-        prepare_pch()
-    assert not (dev / "build" / "esphome_pch.h.gch.sum").exists()
-    assert not (dev / "build" / "esphome_pch.h.gch.failed").exists()
-
-
-def test_write_project_pch_disabled_writes_no_header(
-    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
-) -> None:
-    from esphome.build_gen.espidf import write_project
-
-    monkeypatch.setenv("ESPHOME_PCH_ENABLE", "0")
-    _write_project_description(tmp_path, {})
-    CORE.build_path = tmp_path
-    with (
-        patch("esphome.build_gen.espidf.get_esp32_variant", return_value="ESP32"),
-        patch.object(CORE, "name", "test"),
-    ):
-        write_project()
-    assert not (tmp_path / "build" / "esphome_pch.h").exists()
-
-
-def test_write_project_writes_pch_header(tmp_path: Path) -> None:
-    """The header write_project emits is what _pch_cmake() force-includes;
-    this pairing is the one non-fail-safe path in the design."""
-    from esphome.build_gen.espidf import write_project
-    from esphome.build_helpers.pch import PCH_DEFAULT_HEADERS, pch_header_text
-
-    _write_project_description(tmp_path, {})
-    CORE.build_path = tmp_path
-    with (
-        patch("esphome.build_gen.espidf.get_esp32_variant", return_value="ESP32"),
-        patch.object(CORE, "name", "test"),
-    ):
-        write_project()
-    assert (tmp_path / "build" / "esphome_pch.h").read_text() == pch_header_text(
-        PCH_DEFAULT_HEADERS
-    )
-
-
-def test_prepare_pch_stale_bailout_removes_gch(tmp_path: Path) -> None:
-    """A stale .gch must not survive when no compile command is available."""
-    from esphome.build_gen.espidf import prepare_pch
-
-    dev = _make_pch_device(tmp_path, "dev_s")
-    CORE.build_path = dev
-    gch = dev / "build" / "esphome_pch.h.gch"
-    gch.write_bytes(b"stale")
-    (dev / "build" / "esphome_pch.h.gch.sum").write_text("stale-sum\n")
-    (dev / "build" / "compile_commands.json").unlink()
-    with patch.object(CORE, "name", "test"):
-        prepare_pch()
-    assert not gch.exists()
-    assert not (dev / "build" / "esphome_pch.h.gch.sum").exists()
-
-
-def test_prepare_pch_zero_exit_without_gch_is_failure(tmp_path: Path) -> None:
-    from esphome.build_gen.espidf import prepare_pch
-
-    dev = _make_pch_device(tmp_path, "dev_z")
-    CORE.build_path = dev
-
-    def no_output(cmd, **kwargs):
-        return subprocess.CompletedProcess(cmd, 0, "", "")
-
-    with (
-        patch.object(CORE, "name", "test"),
-        patch("esphome.build_helpers.pch.subprocess.run", side_effect=no_output),
-    ):
-        prepare_pch()
-    assert not (dev / "build" / "esphome_pch.h.gch.sum").exists()
-    assert (dev / "build" / "esphome_pch.h.gch.failed").exists()
-
-
-def test_prepare_pch_bumps_header_for_object_depends(tmp_path: Path) -> None:
-    """The OBJECT_DEPENDS edge watches the header; a rebuilt .gch must bump
-    it so pch-consuming TUs recompile."""
-    import os as _os
-
-    from esphome.build_gen.espidf import prepare_pch
-
-    dev = _make_pch_device(tmp_path, "dev_t")
-    CORE.build_path = dev
-    header = dev / "build" / "esphome_pch.h"
-    gch = dev / "build" / "esphome_pch.h.gch"
-    _os.utime(header, (0, 0))
-    before = header.stat().st_mtime
-
-    def fake_compile(cmd, **kwargs):
-        gch.write_bytes(b"gch")
-        return subprocess.CompletedProcess(cmd, 0, "", "")
-
-    with (
-        patch.object(CORE, "name", "test"),
-        patch("esphome.build_helpers.pch.subprocess.run", side_effect=fake_compile),
-    ):
-        prepare_pch()
-    assert header.stat().st_mtime > before
-
-
-def test_component_cmakelists_pch_object_depends() -> None:
-    from esphome.build_gen.espidf import get_component_cmakelists
-
-    content = get_component_cmakelists()
-    assert 'OBJECT_DEPENDS "${CMAKE_BINARY_DIR}/esphome_pch.h"' in content
-
-
-def test_prepare_pch_command_change_invalidates_sum(tmp_path: Path) -> None:
-    """A flag-only change in the compile DB must rebuild the .gch."""
-    from esphome.build_gen.espidf import prepare_pch
-
-    dev = _make_pch_device(tmp_path, "dev_c")
-    CORE.build_path = dev
-    gch = dev / "build" / "esphome_pch.h.gch"
-
-    def fake_compile(cmd, **kwargs):
-        gch.write_bytes(b"gch")
-        return subprocess.CompletedProcess(cmd, 0, "", "")
-
-    with (
-        patch.object(CORE, "name", "test"),
-        patch("esphome.build_helpers.pch.subprocess.run", side_effect=fake_compile),
-    ):
-        prepare_pch()
-        first = (dev / "build" / "esphome_pch.h.gch.sum").read_text()
-        db = dev / "build" / "compile_commands.json"
-        db.write_text(db.read_text().replace("-DX=1", "-DX=2"))
-        prepare_pch()
-    assert (dev / "build" / "esphome_pch.h.gch.sum").read_text() != first
-
-
-def test_prepare_pch_keeps_user_force_includes(tmp_path: Path) -> None:
-    from esphome.build_helpers.pch import pch_compile_command
-
-    dev = _make_pch_device(tmp_path, "dev_u")
-    CORE.build_path = dev
-    build = dev / "build"
-    src_file = str(dev / "src" / "esphome" / "a.cpp")
-    build.joinpath("compile_commands.json").write_text(
-        json.dumps(
-            [
-                {
-                    "directory": str(build),
-                    "command": (
-                        "g++ -include user.h -include esphome_pch.h "
-                        f"-o a.obj -c {src_file}"
-                    ),
-                    "file": src_file,
-                }
-            ]
-        )
-    )
-    cmd, _ = pch_compile_command(build, build / "esphome_pch.h", build / "x.gch")
-    assert "user.h" in cmd
-    assert "esphome_pch.h" not in " ".join(cmd[:-3])
-
-
-def test_prepare_pch_identity_unknown_discards(tmp_path: Path) -> None:
-    """An OSError from the checksum discards artifacts and skips the pch."""
-    from esphome.build_gen.espidf import prepare_pch
-
-    dev = _make_pch_device(tmp_path, "dev_i")
-    CORE.build_path = dev
-    stale = dev / "build" / "esphome_pch.h.gch"
-    stale.write_bytes(b"stale")
-    with (
-        patch.object(CORE, "name", "test"),
-        patch(
-            "esphome.build_helpers.pch.pch_checksum",
-            side_effect=OSError("stat failed"),
-        ),
-        patch("esphome.build_helpers.pch.subprocess.run", side_effect=AssertionError),
-    ):
-        prepare_pch()
-    assert not stale.exists()
-    assert not (dev / "build" / "esphome_pch.h.gch.sum").exists()
-
-
-def test_prepare_pch_transient_compiler_failure_does_not_latch(
-    tmp_path: Path,
-) -> None:
-    """ENOSPC-style failures clear on their own; no .failed marker."""
-    from esphome.build_gen.espidf import prepare_pch
-
-    dev = _make_pch_device(tmp_path, "dev_e")
-    CORE.build_path = dev
-    calls = []
-
-    def enospc(cmd, **kwargs):
-        calls.append(cmd)
-        return subprocess.CompletedProcess(
-            cmd, 1, "", "fatal error: No space left on device"
-        )
-
-    with (
-        patch.object(CORE, "name", "test"),
-        patch("esphome.build_helpers.pch.subprocess.run", side_effect=enospc),
-    ):
-        prepare_pch()
-        prepare_pch()
-    assert not (dev / "build" / "esphome_pch.h.gch.failed").exists()
-    assert len(calls) == 2

tests/unit_tests/build_helpers/test_ccache.py

@@ -10,7 +10,6 @@ from unittest.mock import patch
 import pytest
 
 from esphome.build_helpers import ccache
-from esphome.core import CORE
 
 
 def test_resolve_opt_out() -> None:
@@ -121,17 +120,3 @@ def test_parse_enable_env_spelling_tables(
     """cv.boolean's spelling tables plus the 1/0 env convention."""
     monkeypatch.setenv("ESPHOME_CCACHE_ENABLE", raw)
     assert ccache.parse_enable_env("ESPHOME_CCACHE_ENABLE") is expected
-
-
-def test_effective_ccache_basedir_prefers_user_value(tmp_path: Path) -> None:
-    CORE.build_path = tmp_path
-    # Drive-qualified on Windows: "/custom/base" is not absolute there
-    base = "C:\\custom\\base" if os.name == "nt" else "/custom/base"
-    with patch.dict(os.environ, {"CCACHE_BASEDIR": base}, clear=True):
-        assert ccache.effective_ccache_basedir() == base
-    with patch.dict(os.environ, {}, clear=True):
-        assert ccache.effective_ccache_basedir() == str(tmp_path.resolve())
-    # Degenerate values would strip substrings ccache never rewrites
-    for bad in ("", "/", "a/b"):
-        with patch.dict(os.environ, {"CCACHE_BASEDIR": bad}, clear=True):
-            assert ccache.effective_ccache_basedir() == str(tmp_path.resolve())

tests/unit_tests/build_helpers/test_idedata.py

@@ -85,87 +85,6 @@ def test_parse_entry_resolves_relative_includes() -> None:
     assert all(Path(inc).is_absolute() for inc in includes)
 
 
-def test_parse_entry_resolves_force_include_path(tmp_path: Path) -> None:
-    """The pch -include is emitted relative to the build dir; idedata must
-    resolve it so cached flags work from any cwd."""
-    (tmp_path / "esphome_pch.h").write_text("")
-    entry = _entry(
-        str(tmp_path),
-        f"{tmp_path}/src/esphome/x.cpp",
-        "g++ -include esphome_pch.h -c x.cpp",
-    )
-
-    _, _, _, cxx_flags = idedata.parse_entry(entry)
-
-    idx = cxx_flags.index("-include")
-    resolved = cxx_flags[idx + 1]
-    assert Path(resolved).is_absolute()
-    assert resolved == str(tmp_path / "esphome_pch.h").replace("\\", "/")
-
-
-def test_parse_entry_resolves_joined_force_include(tmp_path: Path) -> None:
-    """The joined -includefoo.h spelling takes the same resolve path."""
-    (tmp_path / "esphome_pch.h").write_text("")
-    entry = _entry(
-        str(tmp_path),
-        f"{tmp_path}/src/esphome/x.cpp",
-        "g++ -includeesphome_pch.h -c x.cpp",
-    )
-
-    _, _, _, cxx_flags = idedata.parse_entry(entry)
-
-    resolved = cxx_flags[cxx_flags.index("-include") + 1]
-    assert resolved == str(tmp_path / "esphome_pch.h").replace("\\", "/")
-
-
-def test_parse_entry_keeps_search_chain_force_include(tmp_path: Path) -> None:
-    """-include names resolved via the -I chain (libretiny's Arduino.h) must
-    not be re-anchored to a nonexistent build-dir path."""
-    entry = _entry(
-        str(tmp_path),
-        f"{tmp_path}/src/esphome/x.cpp",
-        "g++ -include Arduino.h -c x.cpp",
-    )
-
-    _, _, _, cxx_flags = idedata.parse_entry(entry)
-
-    assert cxx_flags[cxx_flags.index("-include") + 1] == "Arduino.h"
-
-
-def test_parse_entry_warns_on_vanished_force_include(
-    tmp_path: Path, caplog: pytest.LogCaptureFixture
-) -> None:
-    """A build-dir force-include deleted by clean_build must leave a trail;
-    a name resolvable via the -I chain must not warn."""
-    inc = tmp_path / "inc"
-    inc.mkdir()
-    (inc / "Arduino.h").write_text("")
-    entry = _entry(
-        str(tmp_path),
-        f"{tmp_path}/src/esphome/x.cpp",
-        f"g++ -I{inc} -include Arduino.h -include esphome_pch.h -c x.cpp",
-    )
-
-    _, _, _, cxx_flags = idedata.parse_entry(entry)
-
-    assert "Arduino.h" in cxx_flags
-    assert "esphome_pch.h" in caplog.text
-    assert "Arduino.h" not in caplog.text
-
-
-def test_parse_entry_drops_trailing_force_include(
-    tmp_path: Path, caplog: pytest.LogCaptureFixture
-) -> None:
-    entry = _entry(
-        str(tmp_path), f"{tmp_path}/src/esphome/x.cpp", "g++ -c x.cpp -include"
-    )
-
-    _, _, _, cxx_flags = idedata.parse_entry(entry)
-
-    assert "-include" not in cxx_flags
-    assert "no argument" in caplog.text
-
-
 def test_parse_entry_skips_dependency_flags() -> None:
     """Dependency-generation flags (and their args) are dropped."""
     entry = _entry(
@@ -185,7 +104,7 @@ def test_expand_response_files(tmp_path: Path) -> None:
     rsp = tmp_path / "flags.rsp"
     rsp.write_text("-DFROM_RSP -I/rsp/inc")
 
-    tokens = idedata.expand_response_files(
+    tokens = idedata._expand_response_files(
         ["g++", f"@{rsp.name}", "-c", "x.cpp"], tmp_path
     )
 
@@ -196,7 +115,7 @@ def test_expand_response_files(tmp_path: Path) -> None:
 
 def test_expand_response_files_keeps_literal_when_missing(tmp_path: Path) -> None:
     """An unreadable ``@file`` token is kept verbatim rather than dropped."""
-    tokens = idedata.expand_response_files(["g++", "@nope.rsp"], tmp_path)
+    tokens = idedata._expand_response_files(["g++", "@nope.rsp"], tmp_path)
     assert "@nope.rsp" in tokens
 
 
@@ -408,7 +327,7 @@ def test_split_command_preserves_paths_and_unescapes_quotes() -> None:
     r"""Backslash paths survive while ``\"`` define-quoting is unescaped."""
     command = r"C:\esp\bin\riscv32-esp-elf-g++.exe -DVER=\"1.2.3\" -IC:/inc/a -c x.cpp"
 
-    tokens = idedata.split_command(command)
+    tokens = idedata._split_command(command)
 
     assert tokens[0] == r"C:\esp\bin\riscv32-esp-elf-g++.exe"
     assert '-DVER="1.2.3"' in tokens
@@ -422,8 +341,8 @@ def test_split_command_empty_returns_empty() -> None:
     Guards against ``CommandLineToArgvW("")`` returning the current process name
     instead of an empty list.
     """
-    assert idedata.split_command("") == []
-    assert idedata.split_command("   ") == []
+    assert idedata._split_command("") == []
+    assert idedata._split_command("   ") == []
 
 
 @pytest.mark.skipif(os.name != "nt", reason="Windows argv tokenization")
@@ -584,9 +503,9 @@ def test_load_or_build_idedata_rebuilds_non_dict_cache(tmp_path: Path) -> None:
 def test_is_launcher_matches_only_known_launchers() -> None:
     """Compilers of any shape pass; only the closed launcher set matches."""
     for token in ("/t/g++-13", "gcc-8.4.0", "clang++-17", "armcc", "icx", "cc"):
-        assert not idedata.is_launcher(token)
+        assert not idedata._is_launcher(token)
     for token in ("/opt/homebrew/bin/ccache", "CCACHE.EXE", "distcc", "sccache"):
-        assert idedata.is_launcher(token)
+        assert idedata._is_launcher(token)
 
 
 def test_load_or_build_idedata_corrupted_cache_is_logged(

tests/unit_tests/build_helpers/test_pch.py

@@ -1,218 +0,0 @@
-"""Tests for esphome.build_helpers.pch."""
-
-from __future__ import annotations
-
-import os
-from pathlib import Path
-from unittest.mock import patch
-
-import pytest
-
-from esphome.build_helpers import pch
-
-
-def _write(src_dir: Path, name: str, content: str) -> None:
-    path = src_dir / name
-    path.parent.mkdir(parents=True, exist_ok=True)
-    path.write_text(content)
-
-
-@pytest.mark.parametrize(
-    ("value", "expected"),
-    [
-        (None, True),
-        ("1", True),
-        ("0", False),
-        ("false", False),
-        ("", False),
-    ],
-)
-def test_pch_enabled(value: str | None, expected: bool) -> None:
-    env = {} if value is None else {"ESPHOME_PCH_ENABLE": value}
-    with patch.dict(os.environ, env, clear=True):
-        assert pch.pch_enabled() is expected
-
-
-def test_ccache_pch_env_empty_until_emitted() -> None:
-    """No sloppiness relaxation for a build that skipped the pch."""
-    with patch.dict(os.environ, {}, clear=True):
-        assert pch.ccache_pch_env() == {}
-
-
-def test_ccache_pch_env_enabled() -> None:
-    pch.mark_pch_emitted()
-    with patch.dict(os.environ, {}, clear=True):
-        env = pch.ccache_pch_env()
-    assert env["CCACHE_SLOPPINESS"] == "pch_defines,time_macros"
-    assert env["CCACHE_PCH_EXTSUM"] == "true"
-
-
-def test_ccache_pch_env_disabled() -> None:
-    with patch.dict(os.environ, {"ESPHOME_PCH_ENABLE": "0"}, clear=True):
-        assert pch.ccache_pch_env() == {}
-
-
-def test_ccache_pch_env_token_check_is_membership_not_substring(
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    """A token merely containing ours must not suppress the union."""
-    pch.mark_pch_emitted()
-    with patch.dict(os.environ, {"CCACHE_SLOPPINESS": "pch_defines_extra"}, clear=True):
-        env = pch.ccache_pch_env()
-    assert env["CCACHE_SLOPPINESS"] == "pch_defines_extra,pch_defines,time_macros"
-
-
-def test_ccache_pch_env_unions_user_sloppiness(
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    """Without pch_defines/time_macros ccache declines every pch-consuming
-    compile, so missing tokens are unioned onto the user's value."""
-    pch.mark_pch_emitted()
-    with patch.dict(os.environ, {"CCACHE_SLOPPINESS": "locale"}, clear=True):
-        env = pch.ccache_pch_env()
-    assert env["CCACHE_SLOPPINESS"] == "locale,pch_defines,time_macros"
-    assert env["CCACHE_PCH_EXTSUM"] == "true"
-    assert "Adding pch_defines,time_macros" in caplog.text
-    caplog.clear()
-    with patch.dict(
-        os.environ, {"CCACHE_SLOPPINESS": "pch_defines,time_macros"}, clear=True
-    ):
-        env = pch.ccache_pch_env()
-    assert "CCACHE_SLOPPINESS" not in env
-    assert not caplog.records
-
-
-def test_pch_header_text_preserves_order() -> None:
-    text = pch.pch_header_text(["b.h", "a.h"])
-    assert text == '#include "b.h"\n#include "a.h"\n'
-
-
-def test_include_closure_resolves_relative_and_root(tmp_path: Path) -> None:
-    """Sibling includes resolve against the includer's directory first,
-    full paths against the src root; unresolvable names end the walk."""
-    _write(tmp_path, "esphome/components/x/a.h", '#include "b.h"\n')
-    _write(
-        tmp_path,
-        "esphome/components/x/b.h",
-        '#include "esphome/core/deep.h"\n#include <system.h>\n#include "missing.h"\n',
-    )
-    _write(tmp_path, "esphome/core/deep.h", "")
-    closure = pch._include_closure(tmp_path, ["esphome/components/x/a.h"])
-    assert sorted(closure) == [
-        "esphome/components/x/a.h",
-        "esphome/components/x/b.h",
-        "esphome/core/deep.h",
-    ]
-
-
-def test_include_closure_handles_cycles(tmp_path: Path) -> None:
-    _write(tmp_path, "a.h", '#include "b.h"\n')
-    _write(tmp_path, "b.h", '#include "a.h"\n')
-    assert sorted(pch._include_closure(tmp_path, ["a.h"])) == ["a.h", "b.h"]
-
-
-def test_include_closure_blocks_parent_escape(tmp_path: Path) -> None:
-    _write(tmp_path / "src", "a.h", '#include "../outside.h"\n')
-    (tmp_path / "outside.h").write_text("")
-    assert sorted(pch._include_closure(tmp_path / "src", ["a.h"])) == ["a.h"]
-
-
-def test_pch_checksum_tracks_closure_content(tmp_path: Path) -> None:
-    """A transitive header edit or an extra-identity change must change the
-    digest; unrelated files must not."""
-    _write(tmp_path, "root.h", '#include "nested.h"\n')
-    _write(tmp_path, "nested.h", "int a;\n")
-    _write(tmp_path, "unrelated.h", "int u;\n")
-    base = pch.pch_checksum(tmp_path, ["root.h"], ["id"])
-    assert base == pch.pch_checksum(tmp_path, ["root.h"], ["id"])
-    assert base != pch.pch_checksum(tmp_path, ["root.h"], ["other-id"])
-    _write(tmp_path, "unrelated.h", "int changed;\n")
-    assert base == pch.pch_checksum(tmp_path, ["root.h"], ["id"])
-    _write(tmp_path, "nested.h", "int b;\n")
-    assert base != pch.pch_checksum(tmp_path, ["root.h"], ["id"])
-
-
-@pytest.mark.skipif(
-    os.name == "nt" or os.geteuid() == 0, reason="chmod is ineffective here"
-)
-def test_include_closure_fails_closed_on_unreadable(
-    tmp_path: Path, caplog: pytest.LogCaptureFixture
-) -> None:
-    """A marker would truncate the transitive walk; the OSError propagates
-    so callers compile without a pch."""
-    _write(tmp_path, "a.h", '#include "locked.h"\n')
-    locked = tmp_path / "locked.h"
-    locked.write_text("")
-    locked.chmod(0)
-    try:
-        with pytest.raises(OSError):
-            pch._include_closure(tmp_path, ["a.h"])
-    finally:
-        locked.chmod(0o644)
-    assert "Could not read locked.h" in caplog.text
-
-
-def test_pch_extra_scripts_gated(monkeypatch: pytest.MonkeyPatch) -> None:
-    with patch.dict(os.environ, {}, clear=True):
-        assert pch.pch_extra_scripts() == ["post:pch.py"]
-    monkeypatch.setenv("ESPHOME_PCH_ENABLE", "0")
-    assert pch.pch_extra_scripts() == []
-
-
-def test_include_closure_raises_when_identity_unknown(
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    """An unreadable header propagates; callers compile without a pch."""
-
-    class _BadFile:
-        def stat(self):  # noqa: ANN202 -- regular-file mode only
-            import os
-            import stat as stat_mod
-
-            return os.stat_result((stat_mod.S_IFREG | 0o644,) + (0,) * 9)
-
-        def read_bytes(self) -> bytes:
-            raise OSError("read failed")
-
-    class _FakeSrcDir:
-        def __truediv__(self, rel: str) -> _BadFile:
-            return _BadFile()
-
-    with pytest.raises(OSError, match="read failed"):
-        pch._include_closure(_FakeSrcDir(), ["a.h"])
-    assert "Could not read a.h" in caplog.text
-
-
-def test_include_closure_survives_non_utf8_include_name(tmp_path: Path) -> None:
-    """A non-UTF-8 quoted include must not abort the build; it simply does
-    not resolve and ends the walk."""
-    (tmp_path / "a.h").write_bytes(b'#include "bad\xff.h"\n#include "b.h"\n')
-    (tmp_path / "b.h").write_text("")
-    closure = pch._include_closure(tmp_path, ["a.h"])
-    assert set(closure) == {"a.h", "b.h"}
-
-
-def test_pch_checksum_survives_surrogate_extra(tmp_path: Path) -> None:
-    """Install paths from non-UTF-8 filesystems carry surrogates; hashing
-    them must not raise past the caller's identity-unknown guard."""
-    assert pch.pch_checksum(tmp_path, [], ["/opt/bad\udcff/framework"])
-
-
-def test_include_closure_walks_angle_includes_under_src(tmp_path: Path) -> None:
-    """An angle include resolving under src/ must enter the digest; one
-    that does not simply ends the walk."""
-    _write(tmp_path, "a.h", "#include <local.h>\n#include <Arduino.h>\n")
-    (tmp_path / "local.h").write_text("")
-    closure = pch._include_closure(tmp_path, ["a.h"])
-    assert set(closure) == {"a.h", "local.h"}
-
-
-def test_ccache_pch_env_warns_on_falsy_extsum(
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    """A user CCACHE_PCH_EXTSUM=false makes ccache hash the .gch bytes."""
-    pch.mark_pch_emitted()
-    with patch.dict(os.environ, {"CCACHE_PCH_EXTSUM": "false"}, clear=True):
-        env = pch.ccache_pch_env()
-    assert "CCACHE_PCH_EXTSUM" not in env
-    assert "disables pch caching" in caplog.text

tests/unit_tests/components/esp8266/test_toolchain_validation.py

@@ -1,193 +0,0 @@
-"""Tests for the native (non-PlatformIO) toolchain config validation."""
-
-from __future__ import annotations
-
-from collections.abc import Generator
-from pathlib import Path
-from types import SimpleNamespace
-from unittest.mock import patch
-
-import pytest
-
-from esphome.components import esp8266
-from esphome.components.esp8266 import (
-    ARDUINO_FRAMEWORK_SCHEMA,
-    _resolve_toolchain,
-    _validate_native_toolchain,
-)
-import esphome.config_validation as cv
-from esphome.const import (
-    CONF_BOARD,
-    CONF_FRAMEWORK,
-    CONF_PLATFORM_VERSION,
-    CONF_SOURCE,
-    CONF_TOOLCHAIN,
-    CONF_VERSION,
-    Toolchain,
-)
-from esphome.core import CORE, EsphomeError
-from esphome.types import ConfigType
-
-
-@pytest.fixture(autouse=True)
-def _arduino_toolchain() -> Generator[None]:
-    # The suite-wide reset_core fixture clears CORE.toolchain after each test
-    CORE.toolchain = Toolchain.ARDUINO
-    esp8266._DECODE_WARNED_AT.clear()
-    yield
-    esp8266._DECODE_WARNED_AT.clear()
-
-
-def _config(
-    board: str = "nodemcuv2",
-    version: str = "3.1.2",
-    source: str | None = None,
-    platform_version: str | None = None,
-) -> ConfigType:
-    framework: dict[str, str] = {CONF_VERSION: version}
-    if source is not None:
-        framework[CONF_SOURCE] = source
-    if platform_version is not None:
-        framework[CONF_PLATFORM_VERSION] = platform_version
-    # The real schema fills the source/platform_version defaults, so these
-    # tests validate against what config validation actually emits
-    return {
-        CONF_FRAMEWORK: ARDUINO_FRAMEWORK_SCHEMA(framework),
-        CONF_BOARD: board,
-    }
-
-
-def test_valid_config_passes() -> None:
-    config = _config()
-    assert _validate_native_toolchain(config) is config
-
-
-def test_platformio_toolchain_skips_checks() -> None:
-    # 3.0.2 is pio-legal (>= the global 3.0.0 floor) but below the native
-    # toolchain's own 3.1.1 floor; the bogus board only the native path checks
-    CORE.toolchain = Toolchain.PLATFORMIO
-    config = _config(board="not_a_board", version="3.0.2")
-    assert _validate_native_toolchain(config) is config
-
-
-def test_version_below_floor_rejected() -> None:
-    # 3.1.0 has no registry package, so the native floor is 3.1.1
-    with pytest.raises(cv.Invalid, match="3.1.1 or newer"):
-        _validate_native_toolchain(_config(version="3.1.0"))
-
-
-def test_version_at_floor_accepted() -> None:
-    _validate_native_toolchain(_config(version="3.1.1"))
-
-
-def test_custom_platform_version_warns_and_is_dropped(
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    config = _config(platform_version="platformio/espressif8266@4.0.1")
-    _validate_native_toolchain(config)
-    assert "'platform_version' is ignored" in caplog.text
-    assert CONF_PLATFORM_VERSION not in config[CONF_FRAMEWORK]
-
-
-def test_default_platform_version_does_not_warn(
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    config = _config()
-    _validate_native_toolchain(config)
-    assert "'platform_version' is ignored" not in caplog.text
-    assert CONF_PLATFORM_VERSION not in config[CONF_FRAMEWORK]
-
-
-def test_custom_source_rejected() -> None:
-    with pytest.raises(cv.Invalid, match="custom framework source"):
-        _validate_native_toolchain(
-            _config(source="https://github.com/esp8266/Arduino.git")
-        )
-
-
-def test_unsupported_board_rejected() -> None:
-    with pytest.raises(cv.Invalid, match="not supported by"):
-        _validate_native_toolchain(_config(board="not_a_board"))
-
-
-def test_yaml_toolchain_key_resolves() -> None:
-    """The documented `toolchain: arduino` YAML key selects the native path."""
-    CORE.toolchain = None
-    _resolve_toolchain({CONF_TOOLCHAIN: Toolchain.ARDUINO})
-    assert CORE.toolchain == Toolchain.ARDUINO
-    assert CORE.using_toolchain_arduino
-
-
-def test_yaml_toolchain_key_defaults_to_platformio() -> None:
-    CORE.toolchain = None
-    _resolve_toolchain({})
-    assert CORE.toolchain == Toolchain.PLATFORMIO
-
-
-def test_decode_pc_native_missing_tools_warns_once(
-    tmp_path: Path, caplog: pytest.LogCaptureFixture
-) -> None:
-    """A stack dump of many addresses produces one missing-tool warning."""
-
-    with (
-        patch(
-            "esphome.arduino8266.toolchain.get_addr2line_path",
-            return_value=tmp_path / "missing-addr2line",
-        ),
-        patch(
-            "esphome.arduino8266.toolchain.get_elf_path",
-            return_value=tmp_path / "missing.elf",
-        ),
-    ):
-        esp8266._decode_pc({}, "40201234")
-        esp8266._decode_pc({}, "40201238")
-    assert caplog.text.count("Cannot decode crash addresses") == 1
-
-
-def test_decode_pc_platformio_missing_tools_warns_once(
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    """The PlatformIO branch reports a missing addr2line/ELF at the same
-    warning level as the native one; raw undecoded addresses with no
-    stated reason are undiagnosable at default log level."""
-
-    CORE.toolchain = Toolchain.PLATFORMIO
-    idedata = SimpleNamespace(addr2line_path=None, firmware_elf_path=None)
-    with patch("esphome.platformio.toolchain.get_idedata", return_value=idedata):
-        esp8266._decode_pc({}, "40201234")
-        esp8266._decode_pc({}, "40201238")
-    assert caplog.text.count("Cannot decode crash addresses") == 1
-
-
-def test_resolve_toolchain_rejects_unsupported() -> None:
-    """ESP8266 rejects a CLI toolchain it cannot serve, like every platform."""
-
-    CORE.toolchain = Toolchain.SDK_NRF
-    with pytest.raises(cv.Invalid, match="Unsupported toolchain 'sdk-nrf'"):
-        _resolve_toolchain({})
-
-
-def test_run_compile_platformio_falls_through() -> None:
-    """Under toolchain: platformio the hook returns False without touching
-    the native backend; this is what keeps existing users on PlatformIO."""
-    CORE.toolchain = Toolchain.PLATFORMIO
-    with patch("esphome.arduino8266.toolchain.run_compile") as mock_native:
-        assert esp8266.run_compile(SimpleNamespace(), {}) is False
-    mock_native.assert_not_called()
-
-
-def test_run_compile_arduino_failure_raises() -> None:
-    """A non-zero native build fails by name instead of returning success."""
-    CORE.verbose = False
-    with (
-        patch("esphome.arduino8266.toolchain.run_compile", return_value=1),
-        pytest.raises(EsphomeError, match="native build failed"),
-    ):
-        esp8266.run_compile(SimpleNamespace(), {})
-
-
-def test_copy_files_native_skips_platformio_scripts(tmp_path: Path) -> None:
-    """The native build writes no PlatformIO extra scripts."""
-    CORE.build_path = tmp_path
-    esp8266.copy_files()
-    assert list(tmp_path.iterdir()) == []

tests/unit_tests/core/test_config.py

@@ -1429,3 +1429,12 @@ async def test_add_platformio_options_native_arduino(
     assert "board_build.ldscript is ignored" in caplog.text
     assert "'arduino' toolchain" in caplog.text
     assert "upload_speed" not in caplog.text
+
+
+def test_esp8266_rejects_unsupported_cli_toolchain() -> None:
+    """Until the native backend lands, ESP8266 serves only PlatformIO."""
+    from esphome.components.esp8266 import CONFIG_SCHEMA
+
+    CORE.toolchain = Toolchain.ARDUINO
+    with pytest.raises(cv.Invalid, match="Unsupported toolchain 'arduino'"):
+        CONFIG_SCHEMA({"board": "nodemcuv2"})

tests/unit_tests/fixtures/lazy_imports/native_upload_fast_path.py

@@ -1,65 +0,0 @@
-"""Run the native-toolchain serial-upload path and report heavy modules.
-
-Executed as a subprocess by test_lazy_imports.py: heavy module names come
-in on argv, the ones found in sys.modules afterwards go out on stdout.
-``upload_using_esptool`` dispatches native toolchains through a
-toolchain-keyed table; if someone routes it back through the platform
-component packages (esp32 or esp8266), this reports the leak.
-"""
-
-import os
-from pathlib import Path
-import sys
-import tempfile
-from unittest.mock import patch
-
-from _leak_report import print_leaked_modules
-
-from esphome.__main__ import upload_using_esptool
-from esphome.const import (
-    CONF_ESPHOME,
-    KEY_CORE,
-    KEY_ESP32,
-    KEY_TARGET_PLATFORM,
-    KEY_VARIANT,
-    Toolchain,
-)
-from esphome.core import CORE
-
-# An ambient ESPHOME_USE_SUBPROCESS would route past the patched
-# run_external_command into run_external_process and confuse the checks.
-os.environ.pop("ESPHOME_USE_SUBPROCESS", None)
-
-config = {CONF_ESPHOME: {"platformio_options": {}}}
-
-with tempfile.TemporaryDirectory() as build_dir:
-    CORE.name = "leaktest"
-    CORE.build_path = build_dir
-
-    for platform, toolchain, backend in (
-        ("esp8266", Toolchain.ARDUINO, "esphome.arduino8266.toolchain"),
-        ("esp32", Toolchain.ESP_IDF, "esphome.espidf.toolchain"),
-    ):
-        CORE.data[KEY_CORE] = {KEY_TARGET_PLATFORM: platform}
-        if platform == "esp32":
-            CORE.data[KEY_ESP32] = {KEY_VARIANT: "ESP32S3"}
-        CORE.toolchain = toolchain
-
-        import importlib
-
-        image = importlib.import_module(backend).get_factory_firmware_path()
-        image.parent.mkdir(parents=True, exist_ok=True)
-        image.write_bytes(b"\x00")
-
-        with patch("esphome.__main__.run_external_command", return_value=0) as mock_run:
-            rc = upload_using_esptool(config, "/dev/ttyUSB0", None, None)
-
-        # Fail loudly if the upload path stopped doing its work; otherwise
-        # an empty leak list could just mean nothing ran.
-        if rc != 0:
-            sys.exit(f"upload_using_esptool({platform}) returned {rc}")
-        cmd = list(mock_run.call_args[0][1:])
-        if str(image) not in [str(Path(c)) for c in cmd]:
-            sys.exit(f"native factory image did not reach esptool: {cmd}")
-
-print_leaked_modules()

tests/unit_tests/test_arduino8266_toolchain.py

@@ -1,657 +0,0 @@
-"""Tests for esphome.arduino8266.toolchain (the ninja build driver)."""
-
-from __future__ import annotations
-
-import os
-from pathlib import Path
-from unittest.mock import MagicMock, patch
-
-import pytest
-
-from esphome.arduino8266 import framework, toolchain
-from esphome.build_helpers.pch import mark_pch_emitted
-import esphome.config_validation as cv
-from esphome.const import (
-    CONF_COMPILE_PROCESS_LIMIT,
-    CONF_ESPHOME,
-    KEY_CORE,
-    KEY_FRAMEWORK_VERSION,
-)
-from esphome.core import CORE, EsphomeError
-
-_SIZE_OUTPUT = """\
-firmware.elf  :
-section       size    addr
-.data         1924    1073643520
-.noinit       56      1073645444
-.text         496     1074790400
-.irom0.text   342804  1075843088
-.text1        27489   1074790896
-.rodata       2588    1073645504
-.bss          26504   1073648096
-Total         401861
-"""
-
-
-@pytest.fixture(autouse=True)
-def _setup_core(tmp_path: Path) -> None:
-    CORE.name = "test8266"
-    CORE.config_path = tmp_path / "test8266.yaml"
-    CORE.build_path = tmp_path
-    CORE.data[KEY_CORE] = {KEY_FRAMEWORK_VERSION: cv.Version(3, 1, 2)}
-    # run_compile verifies the produced artifacts; give every test a build
-    # that "produced" them (tests for the guard delete them again). The
-    # manifest comes first: artifacts must not be older than build.ninja.
-    build_dir = CORE.relative_pioenvs_path("test8266")
-    build_dir.mkdir(parents=True, exist_ok=True)
-    (build_dir / "build.ninja").write_text("# manifest")
-    for artifact in (
-        "firmware.elf",
-        "firmware.bin",
-        "firmware.factory.bin",
-        "firmware.ota.bin",
-    ):
-        (build_dir / artifact).write_bytes(b"")
-
-
-def _paths(tmp_path: Path) -> framework.InstalledPaths:
-    return framework.InstalledPaths(
-        framework=tmp_path / "framework",
-        toolchain=tmp_path / "toolchain",
-        ninja=tmp_path / "ninja",
-    )
-
-
-def test_path_getters(tmp_path: Path) -> None:
-    assert toolchain.get_build_dir() == CORE.relative_pioenvs_path("test8266")
-    assert toolchain.get_elf_path().name == "firmware.elf"
-    # The framework accessor owns the layout and the Windows suffix
-    suffix = ".exe" if os.name == "nt" else ""
-    assert toolchain.get_addr2line_path().name == f"xtensa-lx106-elf-addr2line{suffix}"
-    assert toolchain.get_objdump_path().name == f"xtensa-lx106-elf-objdump{suffix}"
-    assert toolchain.get_readelf_path().name == f"xtensa-lx106-elf-readelf{suffix}"
-
-
-def test_run_compile_build_failure(tmp_path: Path) -> None:
-    with (
-        patch.object(framework, "check_and_install", return_value=_paths(tmp_path)),
-        patch.object(framework, "get_build_env", return_value={}),
-        patch("esphome.build_gen.arduino8266.write_project"),
-        patch.object(
-            toolchain.subprocess, "run", return_value=MagicMock(returncode=2)
-        ) as mock_run,
-        patch.object(toolchain, "_write_compile_commands") as mock_compdb,
-    ):
-        assert toolchain.run_compile({CONF_ESPHOME: {}}, verbose=True) == 2
-    cmd = mock_run.call_args[0][0]
-    assert "-v" in cmd
-    # The compile database is generated before the build runs, so a failed
-    # build cannot leave a stale database behind.
-    mock_compdb.assert_called_once()
-
-
-def test_run_compile_success(tmp_path: Path) -> None:
-    with (
-        patch.object(framework, "check_and_install", return_value=_paths(tmp_path)),
-        patch.object(framework, "get_build_env", return_value={}),
-        # An unchanged manifest is what makes the -n probe run
-        patch("esphome.build_gen.arduino8266.write_project", return_value=False),
-        patch.object(
-            toolchain.subprocess,
-            "run",
-            return_value=MagicMock(returncode=0, stdout="", stderr=""),
-        ) as mock_run,
-        patch.object(toolchain, "_write_compile_commands") as mock_compdb,
-        patch.object(toolchain, "_print_size_summary") as mock_size,
-        patch.object(toolchain, "get_idedata") as mock_idedata,
-    ):
-        rc = toolchain.run_compile(
-            {CONF_ESPHOME: {CONF_COMPILE_PROCESS_LIMIT: 4}}, verbose=False
-        )
-    assert rc == 0
-    # The -n probe runs first, then the real build (cwd, no -C banner)
-    ninja_calls = [c for c in mock_run.call_args_list if "ninja" in str(c[0][0][0])]
-    assert "-n" in ninja_calls[0][0][0]
-    # Explicit targets: a manifest missing them fails as "unknown target"
-    assert ninja_calls[0][0][0][-1] == "firmware.ota.bin"
-    cmd = ninja_calls[1][0][0]
-    assert cmd[-4:] == ["-j", "4", "firmware.factory.bin", "firmware.ota.bin"]
-    assert "-C" not in cmd
-    assert ninja_calls[1][1]["cwd"] is not None
-    mock_compdb.assert_called_once()
-    mock_size.assert_called_once()
-    mock_idedata.assert_called_once()
-
-
-def test_run_compile_noop_skips_the_build_spawn(tmp_path: Path) -> None:
-    """A no-op rebuild stays quiet: the -n probe answers "no work to do"
-    and the real ninja spawn (and its banner) never happens."""
-    with (
-        patch.object(framework, "check_and_install", return_value=_paths(tmp_path)),
-        patch.object(framework, "get_build_env", return_value={}),
-        # An unchanged manifest is what makes the -n probe run
-        patch("esphome.build_gen.arduino8266.write_project", return_value=False),
-        patch.object(
-            toolchain.subprocess,
-            "run",
-            return_value=MagicMock(
-                returncode=0, stdout="ninja: no work to do.\n", stderr=""
-            ),
-        ) as mock_run,
-        patch.object(toolchain, "_write_compile_commands"),
-        patch.object(toolchain, "_print_size_summary"),
-        patch.object(toolchain, "get_idedata"),
-    ):
-        rc = toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False)
-    assert rc == 0
-    ninja_calls = [c for c in mock_run.call_args_list if "ninja" in str(c[0][0][0])]
-    assert len(ninja_calls) == 1
-    assert "-n" in ninja_calls[0][0][0]
-    # Explicit targets: a manifest missing them fails as "unknown target"
-    assert ninja_calls[0][0][0][-1] == "firmware.ota.bin"
-
-
-def test_run_compile_regenerates_stale_compdb(tmp_path: Path) -> None:
-    """An interrupted run can leave build.ninja newer than the compile DB;
-    mere existence must not skip regeneration."""
-    build_dir = toolchain.get_build_dir()
-    build_dir.mkdir(parents=True, exist_ok=True)
-    (build_dir / "build.ninja").write_text("")
-    compdb = build_dir / "compile_commands.json"
-    compdb.write_text("[]")
-    os.utime(compdb, ((build_dir / "build.ninja").stat().st_mtime - 5,) * 2)
-    with (
-        patch.object(framework, "check_and_install", return_value=_paths(tmp_path)),
-        patch.object(framework, "get_build_env", return_value={}),
-        patch("esphome.build_gen.arduino8266.write_project", return_value=False),
-        patch.object(
-            toolchain.subprocess,
-            "run",
-            return_value=MagicMock(
-                returncode=0, stdout="ninja: no work to do.\n", stderr=""
-            ),
-        ),
-        patch.object(toolchain, "_write_compile_commands") as mock_compdb,
-        patch.object(toolchain, "_print_size_summary"),
-        patch.object(toolchain, "get_idedata"),
-    ):
-        assert toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False) == 0
-    mock_compdb.assert_called_once()
-
-
-def test_run_compile_surfaces_probe_diagnostics(
-    tmp_path: Path, caplog: pytest.LogCaptureFixture
-) -> None:
-    """A load-time ninja diagnostic (a generator bug signal) reaches the
-    user even when the no-work branch skips the real spawn."""
-    with (
-        patch.object(framework, "check_and_install", return_value=_paths(tmp_path)),
-        patch.object(framework, "get_build_env", return_value={}),
-        # An unchanged manifest is what makes the -n probe run
-        patch("esphome.build_gen.arduino8266.write_project", return_value=False),
-        patch.object(
-            toolchain.subprocess,
-            "run",
-            return_value=MagicMock(
-                returncode=0,
-                stdout="ninja: no work to do.\n",
-                stderr="ninja: warning: multiple rules generate x\n",
-            ),
-        ),
-        patch.object(toolchain, "_write_compile_commands"),
-        patch.object(toolchain, "_print_size_summary"),
-        patch.object(toolchain, "get_idedata"),
-    ):
-        rc = toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False)
-    assert rc == 0
-    assert "multiple rules generate x" in caplog.text
-
-
-def test_run_compile_missing_artifact_fails(
-    tmp_path: Path, caplog: pytest.LogCaptureFixture
-) -> None:
-    """A zero ninja exit that produced no firmware must not be a green
-    build (size summary and idedata only warn)."""
-    (toolchain.get_build_dir() / "firmware.elf").unlink()
-    with (
-        patch.object(framework, "check_and_install", return_value=_paths(tmp_path)),
-        patch.object(framework, "get_build_env", return_value={}),
-        patch("esphome.build_gen.arduino8266.write_project"),
-        patch.object(
-            toolchain.subprocess,
-            "run",
-            return_value=MagicMock(returncode=0, stdout="", stderr=""),
-        ),
-        patch.object(toolchain, "_write_compile_commands"),
-        patch.object(toolchain, "_print_size_summary") as mock_size,
-        patch.object(toolchain, "get_idedata"),
-    ):
-        rc = toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False)
-    assert rc == 1
-    assert "Build produced no" in caplog.text
-    mock_size.assert_not_called()
-
-
-def test_run_compile_warns_when_idedata_fails(
-    tmp_path: Path, caplog: pytest.LogCaptureFixture
-) -> None:
-    """A failed idedata generation right after a successful build is visible,
-    not deferred to a misleading error in a later command."""
-    with (
-        patch.object(framework, "check_and_install", return_value=_paths(tmp_path)),
-        patch.object(framework, "get_build_env", return_value={}),
-        patch("esphome.build_gen.arduino8266.write_project"),
-        patch.object(
-            toolchain.subprocess,
-            "run",
-            return_value=MagicMock(returncode=0, stdout="", stderr=""),
-        ),
-        patch.object(toolchain, "_write_compile_commands"),
-        patch.object(toolchain, "_print_size_summary"),
-        patch.object(toolchain, "get_idedata", return_value=None),
-    ):
-        assert toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False) == 0
-    assert "No idedata was generated for this build" in caplog.text
-
-
-def test_write_compile_commands(tmp_path: Path) -> None:
-    build_dir = tmp_path / "build"
-    build_dir.mkdir()
-    entries = '[{"file": "a.cpp", "command": "cc"}]\n'
-    with patch.object(
-        toolchain.subprocess,
-        "run",
-        return_value=MagicMock(returncode=0, stdout=entries),
-    ):
-        toolchain._write_compile_commands(tmp_path / "ninja", build_dir, {})
-    assert (build_dir / "compile_commands.json").read_text() == entries
-
-
-@pytest.mark.parametrize(
-    ("stdout", "match"),
-    [
-        ("[]\n", "empty compile database"),
-        # A parse failure names its cause, not the rule-name story
-        ("not json", "unparsable compile database.*not json"),
-    ],
-)
-def test_write_compile_commands_bad_db_raises(
-    tmp_path: Path, stdout: str, match: str
-) -> None:
-    """An empty or unparsable compile database fails the build with its
-    actual cause and drops any stale database."""
-    build_dir = tmp_path / "build"
-    build_dir.mkdir()
-    (build_dir / "compile_commands.json").write_text("[stale]")
-    with (
-        patch.object(
-            toolchain.subprocess,
-            "run",
-            return_value=MagicMock(returncode=0, stdout=stdout),
-        ),
-        pytest.raises(EsphomeError, match=match),
-    ):
-        toolchain._write_compile_commands(tmp_path / "ninja", build_dir, {})
-    assert not (build_dir / "compile_commands.json").exists()
-
-
-def test_write_compile_commands_failure_removes_stale_db(tmp_path: Path) -> None:
-    """A failed compdb run must not leave a stale database behind."""
-    stale = tmp_path / "compile_commands.json"
-    stale.write_text("[]")
-    with (
-        patch.object(
-            toolchain.subprocess,
-            "run",
-            return_value=MagicMock(returncode=1, stderr="boom"),
-        ),
-        pytest.raises(EsphomeError, match="compile_commands"),
-    ):
-        toolchain._write_compile_commands(tmp_path / "ninja", tmp_path, {})
-    assert not stale.exists()
-
-
-def test_parse_app_size(tmp_path: Path) -> None:
-    ld = tmp_path / "eagle.flash.4m.ld"
-    ld.write_text("MEMORY\n{\n  irom0_0_seg :  org = 0x40201010, len = 0xfeff0\n}\n")
-    with patch("esphome.build_gen.arduino8266.get_flash_ld_path", return_value=ld):
-        assert toolchain._parse_app_size(tmp_path, _paths(tmp_path)) == 0xFEFF0
-
-    ld.write_text("MEMORY { }\n")
-    with patch("esphome.build_gen.arduino8266.get_flash_ld_path", return_value=ld):
-        assert toolchain._parse_app_size(tmp_path, _paths(tmp_path)) is None
-
-    # A zero-length segment is bad data, not a budget; warn and drop it
-    ld.write_text("MEMORY\n{\n  irom0_0_seg :  org = 0x40201010, len = 0x0\n}\n")
-    with patch("esphome.build_gen.arduino8266.get_flash_ld_path", return_value=ld):
-        assert toolchain._parse_app_size(tmp_path, _paths(tmp_path)) is None
-
-    with patch(
-        "esphome.build_gen.arduino8266.get_flash_ld_path",
-        return_value=tmp_path / "missing.ld",
-    ):
-        assert toolchain._parse_app_size(tmp_path, _paths(tmp_path)) is None
-
-
-def test_print_size_summary(tmp_path: Path, capsys: pytest.CaptureFixture[str]) -> None:
-    with (
-        patch.object(
-            toolchain.subprocess,
-            "run",
-            return_value=MagicMock(returncode=0, stdout=_SIZE_OUTPUT),
-        ),
-        patch.object(toolchain, "_parse_app_size", return_value=1044464),
-    ):
-        toolchain._print_size_summary(tmp_path, _paths(tmp_path))
-    out = capsys.readouterr().out
-    # Exact PlatformIO shape so script/ci_memory_impact_extract.py can parse it
-    assert "RAM:   [====      ]  37.9% (used 31016 bytes from 81920 bytes)" in out
-    assert "Flash: [====      ]  35.9% (used 375301 bytes from 1044464 bytes)" in out
-
-
-def test_print_size_summary_missing_size_tool_warns(
-    tmp_path: Path, caplog: pytest.LogCaptureFixture
-) -> None:
-    """A missing size binary degrades to a warning; the firmware already
-    linked and must not be discarded."""
-    with patch.object(
-        toolchain.subprocess, "run", side_effect=FileNotFoundError("no size")
-    ):
-        toolchain._print_size_summary(tmp_path, _paths(tmp_path))
-    assert "Could not summarize firmware size" in caplog.text
-
-
-def test_print_size_summary_no_app_size(
-    tmp_path: Path, capsys: pytest.CaptureFixture[str]
-) -> None:
-    with (
-        patch.object(
-            toolchain.subprocess,
-            "run",
-            return_value=MagicMock(returncode=0, stdout=_SIZE_OUTPUT),
-        ),
-        patch.object(toolchain, "_parse_app_size", return_value=None),
-    ):
-        toolchain._print_size_summary(tmp_path, _paths(tmp_path))
-    out = capsys.readouterr().out
-    # Both lines are skipped together: a RAM line without Flash would skew
-    # CI's memory-impact sums across builds
-    assert out == ""
-
-
-def test_print_size_summary_size_tool_failure(
-    tmp_path: Path,
-    capsys: pytest.CaptureFixture[str],
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    with patch.object(
-        toolchain.subprocess,
-        "run",
-        return_value=MagicMock(returncode=1, stdout="", stderr="bad elf"),
-    ):
-        toolchain._print_size_summary(tmp_path, _paths(tmp_path))
-    assert capsys.readouterr().out == ""
-    assert "Could not summarize firmware size" in caplog.text
-
-
-def test_get_idedata_delegates(tmp_path: Path) -> None:
-    with (
-        patch(
-            "esphome.build_helpers.idedata.load_or_build_idedata",
-            return_value={"cc_path": "x"},
-        ) as mock_load,
-        patch.object(toolchain, "resolve_ccache_path", return_value="/cc/ccache"),
-    ):
-        assert toolchain.get_idedata() == {"cc_path": "x"}
-    compile_commands, elf, cache = mock_load.call_args[0]
-    assert compile_commands.name == "compile_commands.json"
-    assert elf.name == "firmware.elf"
-    assert cache.name == "test8266.arduino.json"
-    # The exact configured launcher string is passed for compile DB parsing
-    # (resolve_ccache_path returns a str, untouched on every platform)
-    assert mock_load.call_args.kwargs["launcher"] == "/cc/ccache"
-
-
-def test_get_idedata_no_ccache(tmp_path: Path) -> None:
-    with (
-        patch(
-            "esphome.build_helpers.idedata.load_or_build_idedata", return_value={}
-        ) as mock_load,
-        patch.object(toolchain, "resolve_ccache_path", return_value=None),
-    ):
-        toolchain.get_idedata()
-    assert mock_load.call_args.kwargs["launcher"] is None
-
-
-def test_run_compile_skips_compdb_when_ninja_unchanged(tmp_path: Path) -> None:
-    """An unchanged build.ninja means the compile DB is already current."""
-    build_dir = toolchain.get_build_dir()
-    build_dir.mkdir(parents=True, exist_ok=True)
-    # write_project (stubbed below) always leaves a build.ninja behind
-    (build_dir / "build.ninja").write_text("# manifest")
-
-    def run(regenerate_expected: bool) -> None:
-        with (
-            patch.object(framework, "check_and_install", return_value=_paths(tmp_path)),
-            patch.object(framework, "get_build_env", return_value={}),
-            patch("esphome.build_gen.arduino8266.write_project", return_value=False),
-            patch.object(
-                toolchain.subprocess,
-                "run",
-                return_value=MagicMock(returncode=0, stdout="", stderr=""),
-            ),
-            patch.object(toolchain, "_write_compile_commands") as mock_compdb,
-            patch.object(toolchain, "_print_size_summary"),
-            patch.object(toolchain, "get_idedata"),
-        ):
-            assert toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False) == 0
-        assert mock_compdb.called == regenerate_expected
-
-    # Missing compile DB: regenerated even though build.ninja is unchanged
-    run(regenerate_expected=True)
-    # Present compile DB + unchanged build.ninja: skipped
-    (build_dir / "compile_commands.json").write_text("[]")
-    run(regenerate_expected=False)
-
-
-def test_print_size_summary_unparsable_section(
-    tmp_path: Path,
-    capsys: pytest.CaptureFixture[str],
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    """A totals-relevant section that fails to parse must not produce a
-    confident wrong number; an irrelevant one only warns."""
-    bad = _SIZE_OUTPUT.replace(".bss          26504", ".bss          abc")
-    with patch.object(
-        toolchain.subprocess,
-        "run",
-        return_value=MagicMock(returncode=0, stdout=bad),
-    ):
-        toolchain._print_size_summary(tmp_path, _paths(tmp_path))
-    assert capsys.readouterr().out == ""
-    assert "Unparsable size output" in caplog.text
-
-    caplog.clear()
-    harmless = _SIZE_OUTPUT + ".broken   abc   0\n"
-    with (
-        patch.object(
-            toolchain.subprocess,
-            "run",
-            return_value=MagicMock(returncode=0, stdout=harmless),
-        ),
-        patch.object(toolchain, "_parse_app_size", return_value=1044464),
-    ):
-        toolchain._print_size_summary(tmp_path, _paths(tmp_path))
-    assert "RAM:" in capsys.readouterr().out
-    assert "Unparsable size output" in caplog.text
-
-
-def test_print_size_summary_missing_section_skips_summary(
-    tmp_path: Path,
-    capsys: pytest.CaptureFixture[str],
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    """A totals section absent from the output must not default to zero."""
-    without_bss = "\n".join(
-        line for line in _SIZE_OUTPUT.splitlines() if ".bss" not in line
-    )
-    with patch.object(
-        toolchain.subprocess,
-        "run",
-        return_value=MagicMock(returncode=0, stdout=without_bss),
-    ):
-        toolchain._print_size_summary(tmp_path, _paths(tmp_path))
-    assert capsys.readouterr().out == ""
-    assert "missing section(s) .bss" in caplog.text
-
-
-def test_warn_ignored_platformio_options(caplog: pytest.LogCaptureFixture) -> None:
-    """Component-added options the native build drops are warned by name;
-    the honored ones (lib_ignore, f_cpu, ldscript, build_src_flags,
-    flash_mode) stay quiet."""
-    CORE.platformio_options = {
-        "board_build.ldscript": "eagle.flash.4m2m.ld",
-        "board_build.f_cpu": "160000000L",
-        "board_build.filesystem": "littlefs",
-        "board_build.flash_mode": "dio",
-        "build_src_flags": "-include throw_stubs.h",
-        "lib_ignore": ["Updater"],
-        "upload_speed": "460800",
-    }
-    toolchain._warn_ignored_platformio_options()
-    assert "platformio_options->board_build.filesystem is ignored" in caplog.text
-    assert "native 'arduino' toolchain" in caplog.text
-    assert "board_build.ldscript is ignored" not in caplog.text
-    assert "board_build.f_cpu is ignored" not in caplog.text
-    assert "lib_ignore" not in caplog.text
-    assert "build_src_flags" not in caplog.text
-    assert "flash_mode" not in caplog.text
-    # Component-added upload_speed never gets read under the native
-    # toolchain, so it must warn
-    assert "upload_speed" in caplog.text
-
-
-def test_run_compile_idedata_error_does_not_fail_build(
-    tmp_path: Path, caplog: pytest.LogCaptureFixture
-) -> None:
-    """An unusable compile DB after a successful build warns, never fails."""
-    with (
-        patch.object(framework, "check_and_install", return_value=_paths(tmp_path)),
-        patch.object(framework, "get_build_env", return_value={}),
-        patch("esphome.build_gen.arduino8266.write_project"),
-        patch.object(
-            toolchain.subprocess,
-            "run",
-            return_value=MagicMock(returncode=0, stdout="", stderr=""),
-        ),
-        patch.object(toolchain, "_write_compile_commands"),
-        patch.object(toolchain, "_print_size_summary"),
-        patch.object(
-            toolchain,
-            "get_idedata",
-            side_effect=EsphomeError("compile database is unusable"),
-        ),
-    ):
-        assert toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False) == 0
-    assert "Could not generate idedata: compile database is unusable" in caplog.text
-
-
-def test_run_compile_skipped_size_summary_names_consequence(
-    tmp_path: Path, caplog: pytest.LogCaptureFixture
-) -> None:
-    """A skipped RAM/Flash summary warns about the missing metric; the
-    per-cause warnings alone are invisible to CI harnesses."""
-    with (
-        patch.object(framework, "check_and_install", return_value=_paths(tmp_path)),
-        patch.object(framework, "get_build_env", return_value={}),
-        patch("esphome.build_gen.arduino8266.write_project"),
-        patch.object(
-            toolchain.subprocess,
-            "run",
-            return_value=MagicMock(returncode=0, stdout="", stderr=""),
-        ),
-        patch.object(toolchain, "_write_compile_commands"),
-        patch.object(toolchain, "_print_size_summary", return_value=False),
-        patch.object(toolchain, "get_idedata", return_value=None),
-    ):
-        assert toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False) == 0
-    assert "Firmware size summary unavailable for this build" in caplog.text
-
-
-def test_parse_app_size_non_utf8_ld_warns(
-    tmp_path: Path, caplog: pytest.LogCaptureFixture
-) -> None:
-    """A corrupt (non-UTF-8) linker script degrades to the same warning as
-    an unreadable one, never a traceback after a successful link."""
-    paths = _paths(tmp_path)
-    ld = tmp_path / "corrupt.ld"
-    ld.write_bytes(b"\xff\xfe not utf8")
-    with patch("esphome.build_gen.arduino8266.get_flash_ld_path", return_value=ld):
-        assert toolchain._parse_app_size(tmp_path, paths) is None
-    assert "Cannot read linker script" in caplog.text
-
-
-def test_run_compile_failed_probe_runs_full_build(tmp_path: Path) -> None:
-    """A failing -n probe (e.g. unknown target from a defective manifest)
-    falls through to the real build so the error prints attributably."""
-    probe = MagicMock(returncode=1, stdout="", stderr="")
-    ok = MagicMock(returncode=0, stdout="", stderr="")
-
-    def fake_run(cmd, *args, **kwargs):
-        return probe if "-n" in cmd else ok
-
-    with (
-        patch.object(framework, "check_and_install", return_value=_paths(tmp_path)),
-        patch.object(framework, "get_build_env", return_value={}),
-        patch("esphome.build_gen.arduino8266.write_project", return_value=False),
-        patch.object(toolchain.subprocess, "run", side_effect=fake_run) as mock_run,
-        patch.object(toolchain, "_write_compile_commands"),
-        patch.object(toolchain, "_print_size_summary", return_value=True),
-        patch.object(toolchain, "get_idedata", return_value={}),
-    ):
-        assert toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False) == 0
-    # The real build ran after the failed probe
-    assert any(
-        "firmware.ota.bin" in c[0][0] and "-n" not in c[0][0]
-        for c in mock_run.call_args_list
-    )
-
-
-def test_get_idedata_accepts_preresolved_ccache() -> None:
-    """run_compile threads its resolved ccache through; the probe must not
-    run again."""
-    with (
-        patch(
-            "esphome.build_helpers.idedata.load_or_build_idedata",
-            return_value={"ok": True},
-        ) as mock_build,
-        patch.object(toolchain, "resolve_ccache_path") as mock_resolve,
-    ):
-        assert toolchain.get_idedata("/usr/bin/ccache") == {"ok": True}
-    mock_resolve.assert_not_called()
-    assert mock_build.call_args.kwargs["launcher"] == "/usr/bin/ccache"
-
-
-def test_ccache_env_includes_pch_settings() -> None:
-    """The native build exports the ccache settings the pch needs."""
-    mark_pch_emitted()
-    with patch.dict(os.environ, {}, clear=True):
-        env = framework.ccache_env("/usr/bin/ccache")
-    assert env["CCACHE_SLOPPINESS"] == "pch_defines,time_macros"
-    assert env["CCACHE_PCH_EXTSUM"] == "true"
-
-
-def test_ccache_env_pch_disabled() -> None:
-    with patch.dict(os.environ, {"ESPHOME_PCH_ENABLE": "0"}, clear=True):
-        env = framework.ccache_env("/usr/bin/ccache")
-    assert "CCACHE_SLOPPINESS" not in env
-    assert "CCACHE_PCH_EXTSUM" not in env
-
-
-def test_ccache_env_respects_user_sloppiness() -> None:
-    mark_pch_emitted()
-    with patch.dict(os.environ, {"CCACHE_SLOPPINESS": "locale"}, clear=True):
-        env = framework.ccache_env("/usr/bin/ccache")
-    # The user's tokens survive; the ones the pch needs are unioned on
-    assert env["CCACHE_SLOPPINESS"] == "locale,pch_defines,time_macros"
-    assert env["CCACHE_PCH_EXTSUM"] == "true"

tests/unit_tests/test_espidf_framework.py

@@ -19,7 +19,6 @@ from unittest.mock import MagicMock, patch
 
 import pytest
 
-from esphome.build_helpers.pch import _PCHData
 from esphome.espidf.framework import (
     ESPHOME_STAMP_FILE,
     STAMP_SCHEMA_VERSION,
@@ -1593,14 +1592,10 @@ def _ccache_patches(tmp_path: Path, which: str | None, build_path: Path | None):
             "esphome.espidf.framework.get_idf_tools_path",
             return_value=tmp_path / "tools",
         ),
-        # ccache_defaults_env and the pch emission flag read CORE at call time
+        # ccache_defaults_env (build_helpers.ccache) reads CORE at call time
         patch(
             "esphome.core.CORE",
-            SimpleNamespace(
-                build_path=build_path,
-                # Pre-marked: these env tests model a pch-emitting build
-                data={"pch": _PCHData(emitted=True)},
-            ),
+            SimpleNamespace(build_path=build_path),
         ),
     )
 
@@ -1614,9 +1609,6 @@ def test_ccache_env_default_enabled_when_available(tmp_path: Path) -> None:
     assert env["CCACHE_NOHASHDIR"] == "true"
     assert env["CCACHE_DEPEND"] == "1"
     assert env["CCACHE_BASEDIR"] == str((tmp_path / "build").resolve())
-    # The pch cannot cache under ccache without these
-    assert env["CCACHE_SLOPPINESS"] == "pch_defines,time_macros"
-    assert env["CCACHE_PCH_EXTSUM"] == "true"
 
 
 def test_ccache_env_disabled_when_binary_missing(tmp_path: Path) -> None:

tests/unit_tests/test_espidf_toolchain.py

@@ -93,13 +93,6 @@ def test_get_configured_targets_ci_installs_all(monkeypatch: pytest.MonkeyPatch)
     assert toolchain._get_configured_targets() is None
 
 
-@pytest.fixture(autouse=True)
-def _no_ccache(monkeypatch: pytest.MonkeyPatch) -> None:
-    """Deterministic run_compile: no host ccache probe, no pch work."""
-    monkeypatch.setenv("IDF_CCACHE_ENABLE", "0")
-    monkeypatch.setenv("ESPHOME_PCH_ENABLE", "0")
-
-
 def _setup_build(setup_core: Path) -> tuple[Path, Path]:
     """Point CORE at a build dir; return (compile_commands, idedata cache) paths."""
     CORE.name = "test"
@@ -667,29 +660,3 @@ def test_get_core_framework_version_from_core_data():
 
     CORE.data = {KEY_ESP32: {KEY_IDF_VERSION: cv.Version(5, 5, 4)}}
     assert toolchain._get_core_framework_version() == "5.5.4"
-
-
-def test_run_compile_invokes_prepare_pch_and_survives_failure(
-    setup_core: Path, monkeypatch: pytest.MonkeyPatch
-) -> None:
-    """The pch hook runs before the build and a failure never aborts it."""
-    monkeypatch.setenv("ESPHOME_PCH_ENABLE", "1")
-    _setup_build(setup_core)
-    # A stale .gch must be discarded on the failure path, never consumed
-    build = setup_core / "build" / "test" / "build"
-    build.mkdir(parents=True, exist_ok=True)
-    (build / "esphome_pch.h").write_text("")
-    stale_gch = build / "esphome_pch.h.gch"
-    stale_gch.write_bytes(b"stale")
-
-    with (
-        patch.object(toolchain, "need_reconfigure", return_value=False),
-        patch.object(toolchain, "run_idf_py", return_value=0),
-        patch.object(toolchain, "print_summary"),
-        patch(
-            "esphome.build_gen.espidf.prepare_pch", side_effect=RuntimeError("boom")
-        ) as prepare,
-    ):
-        assert toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False) == 0
-    prepare.assert_called_once()
-    assert not stale_gch.exists()

tests/unit_tests/test_lazy_imports.py

@@ -175,27 +175,6 @@ def test_esptool_upload_fast_path_does_not_import_heavy_modules(
     )
 
 
-def test_native_upload_fast_path_does_not_import_heavy_modules(
-    fixture_path: Path,
-    probe_env: dict[str, str],
-) -> None:
-    """The native-toolchain serial upload dispatches through a
-    toolchain-keyed backend table; resolving the flash image must not drag
-    in the esp32 or esp8266 component package or the validation stack.
-    """
-    leaked = _leaked_from_fixture(
-        fixture_path,
-        probe_env,
-        "native_upload_fast_path.py",
-        extra=("esphome.components.esp8266",),
-    )
-    assert not leaked, (
-        f"native upload_using_esptool pulls in heavy modules: {leaked}. "
-        "The upload fast path skips validation; importing a platform "
-        "component package executes its codegen module by design."
-    )
-
-
 def test_api_client_does_not_import_heavy_modules() -> None:
     """``esphome.api_client`` is on the logs fast path and must stay light.
 

tests/unit_tests/test_main.py

@@ -13,7 +13,7 @@ import sys
 import time
 from types import SimpleNamespace
 from typing import Any, Self
-from unittest.mock import AsyncMock, MagicMock, Mock, PropertyMock, patch
+from unittest.mock import AsyncMock, MagicMock, Mock, patch
 
 import pytest
 from pytest import CaptureFixture
@@ -25,7 +25,6 @@ from esphome.__main__ import (
     Purpose,
     _get_configured_xtal_freq,
     _make_crystal_freq_callback,
-    _native_toolchain_module,
     _redact_with_legacy_fallback,
     _resolve_network_devices,
     _should_subscribe_states,
@@ -7031,7 +7030,7 @@ def test_command_run_rp2040_bootsel_redetects_serial_port() -> None:
 
 def test_command_idedata_esp_idf_prints_json(capsys: CaptureFixture) -> None:
     """Under the native ESP-IDF toolchain, idedata is emitted as JSON."""
-    setup_core(platform=PLATFORM_ESP32)
+    setup_core()
     CORE.toolchain = Toolchain.ESP_IDF
     data = {"cxx_path": "g++", "prog_path": "/build/firmware.elf"}
 
@@ -7045,7 +7044,7 @@ def test_command_idedata_esp_idf_prints_json(capsys: CaptureFixture) -> None:
 
 def test_command_idedata_esp_idf_no_build_errors() -> None:
     """Under ESP-IDF, a missing build (no idedata) returns an error, not a crash."""
-    setup_core(platform=PLATFORM_ESP32)
+    setup_core()
     CORE.toolchain = Toolchain.ESP_IDF
 
     with patch("esphome.espidf.toolchain.get_idedata", return_value=None):
@@ -7219,201 +7218,6 @@ def test_warn_source_tree_mismatch_falls_back_when_stat_fails(
     assert not caplog.text
 
 
-def test_upload_using_esptool_arduino_toolchain(
-    tmp_path: Path,
-    mock_run_external_command_main: Mock,
-) -> None:
-    """The native ESP8266 Arduino toolchain flashes its factory image at
-    0x0, resolved from the toolchain-keyed backend table (deliberately not
-    the platform hook: that import would break the upload fast path)."""
-    setup_core(platform=PLATFORM_ESP8266, tmp_path=tmp_path, name="test")
-    CORE.toolchain = Toolchain.ARDUINO
-    from esphome.arduino8266 import toolchain as native
-
-    factory = native.get_factory_firmware_path()
-    factory.parent.mkdir(parents=True, exist_ok=True)
-    factory.touch()
-
-    config = {CONF_ESPHOME: {"platformio_options": {}}}
-    result = upload_using_esptool(config, "/dev/ttyUSB0", None, None)
-
-    assert result == 0
-    cmd_list = list(mock_run_external_command_main.call_args[0][1:])
-    firmware_offset_idx = cmd_list.index("write-flash") + 4
-    assert cmd_list[firmware_offset_idx] == "0x0"
-    assert cmd_list[firmware_offset_idx + 1] == str(factory)
-
-
-@pytest.mark.parametrize(
-    ("toolchain", "pio_project_written"),
-    [
-        # The native toolchain generates its project at compile time, so
-        # write_cpp_file must not write a platformio.ini; the default
-        # toolchain writes the PlatformIO project files.
-        (Toolchain.ARDUINO, False),
-        (None, True),
-    ],
-)
-def test_write_cpp_file_project_generation_follows_toolchain(
-    tmp_path: Path, toolchain: Toolchain | None, pio_project_written: bool
-) -> None:
-    setup_core(platform=PLATFORM_ESP8266, tmp_path=tmp_path, name="test")
-    CORE.toolchain = toolchain
-
-    with (
-        patch("esphome.writer.write_cpp") as mock_write_cpp,
-        patch("esphome.build_gen.platformio.write_project") as mock_pio_project,
-        patch.object(
-            type(CORE), "cpp_main_section", new_callable=PropertyMock
-        ) as mock_section,
-    ):
-        mock_section.return_value = ""
-        assert main.write_cpp_file() == 0
-
-    mock_write_cpp.assert_called_once()
-    assert mock_pio_project.called is pio_project_written
-
-
-def test_command_idedata_arduino_prints_json(
-    tmp_path: Path, capsys: CaptureFixture
-) -> None:
-    """Under the native ESP8266 Arduino toolchain, idedata is emitted as JSON."""
-    setup_core(platform=PLATFORM_ESP8266, tmp_path=tmp_path)
-    CORE.toolchain = Toolchain.ARDUINO
-    data = {"cxx_path": "g++", "prog_path": "/build/firmware.elf"}
-
-    with patch(
-        "esphome.arduino8266.toolchain.get_idedata", return_value=data
-    ) as mock_get:
-        result = command_idedata(MagicMock(), CORE.config)
-
-    assert result == 0
-    mock_get.assert_called_once_with()
-    assert json.loads(capsys.readouterr().out) == data
-
-
-def test_command_idedata_arduino_no_build_errors(tmp_path: Path) -> None:
-    """A missing native build (no idedata) returns an error, not a crash."""
-    setup_core(platform=PLATFORM_ESP8266, tmp_path=tmp_path)
-    CORE.toolchain = Toolchain.ARDUINO
-
-    with patch("esphome.arduino8266.toolchain.get_idedata", return_value=None):
-        result = command_idedata(MagicMock(), CORE.config)
-
-    assert result == 1
-
-
-@pytest.mark.parametrize(
-    ("platform", "toolchain", "module"),
-    [
-        (PLATFORM_ESP8266, Toolchain.ARDUINO, "esphome.arduino8266.toolchain"),
-        (PLATFORM_ESP32, Toolchain.ESP_IDF, "esphome.espidf.toolchain"),
-    ],
-)
-def test_command_analyze_memory_native_toolchains(
-    tmp_path: Path,
-    mock_write_cpp: Mock,
-    mock_compile_program: Mock,
-    mock_get_esphome_components: Mock,
-    mock_memory_analyzer_cli: Mock,
-    mock_ram_strings_analyzer: Mock,
-    platform: str,
-    toolchain: Toolchain,
-    module: str,
-) -> None:
-    """analyze-memory uses the native toolchain's binutils instead of
-    falling into the PlatformIO branch."""
-    setup_core(platform=platform, tmp_path=tmp_path, name="test_device")
-    CORE.toolchain = toolchain
-
-    config = {CONF_ESPHOME: {CONF_NAME: "test_device"}}
-    # The tools must exist: a missing binutils now fails by name instead of
-    # silently falling back to host tools
-    objdump = tmp_path / "objdump"
-    readelf = tmp_path / "readelf"
-    objdump.write_text("")
-    readelf.write_text("")
-    # The ELF must exist too: the analyzer swallows tool failures, so a
-    # missing image would report zeroes with exit 0
-    firmware_elf = tmp_path / "firmware.elf"
-    firmware_elf.write_text("")
-    with (
-        patch(f"{module}.get_objdump_path", return_value=objdump),
-        patch(f"{module}.get_readelf_path", return_value=readelf),
-        patch(f"{module}.get_elf_path", return_value=firmware_elf),
-    ):
-        result = command_analyze_memory(MockArgs(), config)
-
-    assert result == 0
-    mock_memory_analyzer_cli.assert_called_once_with(
-        str(firmware_elf),
-        str(objdump),
-        str(readelf),
-        set(),
-        idedata=None,
-    )
-
-
-def test_command_analyze_memory_native_missing_elf_fails(
-    tmp_path: Path,
-    mock_write_cpp: Mock,
-    mock_compile_program: Mock,
-    mock_get_esphome_components: Mock,
-    mock_memory_analyzer_cli: Mock,
-    mock_ram_strings_analyzer: Mock,
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    """A missing firmware.elf fails by name instead of an exit-0 zeroed
-    report."""
-    setup_core(platform=PLATFORM_ESP8266, tmp_path=tmp_path, name="test_device")
-    CORE.toolchain = Toolchain.ARDUINO
-
-    config = {CONF_ESPHOME: {CONF_NAME: "test_device"}}
-    objdump = tmp_path / "objdump"
-    readelf = tmp_path / "readelf"
-    objdump.write_text("")
-    readelf.write_text("")
-    module = "esphome.arduino8266.toolchain"
-    with (
-        patch(f"{module}.get_objdump_path", return_value=objdump),
-        patch(f"{module}.get_readelf_path", return_value=readelf),
-        patch(f"{module}.get_elf_path", return_value=tmp_path / "missing.elf"),
-    ):
-        result = command_analyze_memory(MockArgs(), config)
-
-    assert result == 1
-    assert "compile the configuration first" in caplog.text
-    mock_memory_analyzer_cli.assert_not_called()
-
-
-def test_command_analyze_memory_missing_binutils_fails_by_name(
-    tmp_path: Path, caplog: pytest.LogCaptureFixture
-) -> None:
-    """A truncated toolchain install fails naming the missing tool instead
-    of silently analyzing with host binutils."""
-    setup_core(platform="esp8266", tmp_path=tmp_path, name="test_device")
-    CORE.toolchain = Toolchain.ARDUINO
-    config = {CONF_ESPHOME: {CONF_NAME: "test_device"}}
-    module = "esphome.arduino8266.toolchain"
-    with (
-        patch(f"{module}.get_objdump_path", return_value=tmp_path / "missing-objdump"),
-        patch(f"{module}.get_readelf_path", return_value=tmp_path / "readelf"),
-        patch("esphome.__main__.write_cpp", return_value=0),
-        patch("esphome.__main__.compile_program", return_value=0),
-    ):
-        assert command_analyze_memory(MockArgs(), config) == 1
-    assert "missing-objdump" in caplog.text
-    assert "toolchain install may be incomplete" in caplog.text
-
-
-def test_command_idedata_incompatible_toolchain(tmp_path: Path) -> None:
-    """A non-native, non-platformio toolchain errors out cleanly."""
-    setup_core(platform=PLATFORM_ESP32, tmp_path=tmp_path)
-    CORE.toolchain = Toolchain.SDK_NRF
-
-    assert command_idedata(MagicMock(), CORE.config) == 1
-
-
 @pytest.mark.parametrize(
     "error",
     [
@@ -7490,46 +7294,6 @@ def test_compile_program_espidf_idedata_none_warns(
     assert "No idedata was generated" in caplog.text
 
 
-def test_native_toolchain_table_serves_every_native_toolchain() -> None:
-    """Every member of NATIVE_TOOLCHAINS has a backend entry; a gap would
-    surface as a targeted EsphomeError on the one affected config, and this
-    pin keeps the table from drifting when a toolchain is added."""
-    from esphome.const import NATIVE_TOOLCHAINS
-
-    assert {tc for _, tc in main._NATIVE_TOOLCHAIN_MODULES} == set(NATIVE_TOOLCHAINS)
-
-
-def test_native_toolchain_module_missing_backend_raises(tmp_path: Path) -> None:
-    """A native toolchain missing from the backend table is a bug and must
-    fail, not silently degrade to the PlatformIO path."""
-    setup_core(platform=PLATFORM_ESP8266, tmp_path=tmp_path, name="test_device")
-    CORE.toolchain = Toolchain.ARDUINO
-    with (
-        patch.dict(main._NATIVE_TOOLCHAIN_MODULES, clear=True),
-        pytest.raises(EsphomeError, match="no native build backend"),
-    ):
-        _native_toolchain_module()
-
-
-def test_command_analyze_memory_unsupported_toolchain(
-    tmp_path: Path,
-    mock_write_cpp: Mock,
-    mock_compile_program: Mock,
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    """A hook-less non-PlatformIO toolchain is refused by name, never routed
-    into the PlatformIO branch."""
-    setup_core(platform=PLATFORM_NRF52, tmp_path=tmp_path, name="test_device")
-    CORE.toolchain = Toolchain.SDK_NRF
-    mock_write_cpp.return_value = 0
-    mock_compile_program.return_value = 0
-
-    result = command_analyze_memory(MockArgs(), {CONF_ESPHOME: {CONF_NAME: "t"}})
-
-    assert result == 1
-    assert "analyze-memory is not supported" in caplog.text
-
-
 def test_cli_toolchain_skips_the_validated_config_cache(tmp_path: Path) -> None:
     """An explicit --toolchain must run the per-platform validators, so the
     upload/logs fast path becomes a cache miss."""
@@ -7545,29 +7309,6 @@ def test_cli_toolchain_skips_the_validated_config_cache(tmp_path: Path) -> None:
     mock_read.assert_called_once()
 
 
-def test_upload_using_esptool_native_missing_firmware_raises(
-    tmp_path: Path,
-) -> None:
-    """A stale or absent firmware.bin fails by name instead of flashing air."""
-    setup_core(platform=PLATFORM_ESP8266, tmp_path=tmp_path, name="test")
-    CORE.toolchain = Toolchain.ARDUINO
-    with pytest.raises(EsphomeError, match="compile the configuration first"):
-        upload_using_esptool(
-            {CONF_ESPHOME: {"platformio_options": {}}}, "/dev/ttyUSB0", None, None
-        )
-
-
-def test_compile_program_unclaimed_native_toolchain_raises(
-    tmp_path: Path,
-) -> None:
-    """A resolved native toolchain no platform backend claims must fail,
-    never fall through to the PlatformIO project path."""
-    setup_core(platform=PLATFORM_ESP32, tmp_path=tmp_path, name="test_device")
-    CORE.toolchain = Toolchain.ARDUINO  # esp32 has no arduino-native backend
-    with pytest.raises(EsphomeError, match="no platform backend claimed"):
-        compile_program(MockArgs(), {})
-
-
 def test_cli_toolchain_still_refreshes_the_validated_config_cache(
     tmp_path: Path,
 ) -> None:

tests/unit_tests/test_platformio_pch_script.py

@@ -1,460 +0,0 @@
-"""Tests for esphome/platformio/pch.py.script against a fake SCons env."""
-
-from __future__ import annotations
-
-import os
-from pathlib import Path
-import stat
-from unittest.mock import patch
-
-import pytest
-
-from esphome.platformio import toolchain
-
-pytestmark = pytest.mark.skipif(
-    os.name == "nt", reason="the fake compiler is a POSIX shell script"
-)
-
-_SCRIPT = Path(toolchain.__file__).parent / "pch.py.script"
-
-
-class _FakePlatform:
-    packages = {"framework-x": {}, "toolchain-y": {}}
-
-    def get_package_version(self, name: str) -> str:
-        if name == "toolchain-y":
-            raise KeyError(name)
-        return "1.2.3"
-
-    def get_package(self, name: str) -> object | None:
-        return None
-
-
-class _BrokenPlatform(_FakePlatform):
-    def get_package_version(self, name: str) -> str:
-        raise RuntimeError("manifest parse error")
-
-
-class _UnresolvedPlatform(_FakePlatform):
-    """KeyError from a package that IS installed: unresolved identity."""
-
-    def get_package_version(self, name: str) -> str:
-        raise KeyError(name)
-
-    def get_package(self, name: str) -> object:
-        return object()
-
-
-class _FakeSConsEnv(dict):
-    """Just enough of a SCons construction environment for pch.py."""
-
-    def __init__(
-        self,
-        proj_dir: Path,
-        src_dir: Path,
-        cxx: str,
-        flags: list[str],
-        platform_cls: type[_FakePlatform] = _FakePlatform,
-    ):
-        super().__init__(ENV={})
-        self._subst = {
-            "$PROJECT_DIR": str(proj_dir),
-            "$PROJECT_SRC_DIR": str(src_dir),
-            "$CXX": cxx,
-        }
-        self._flags = flags
-        self._platform_cls = platform_cls
-        self.prepended: list[str] = []
-
-    def subst(self, expr: str) -> str:  # noqa: N802
-        return self._subst[expr]
-
-    def subst_list(self, expr: str) -> list[list[str]]:  # noqa: N802
-        return [self._flags]
-
-    def PioPlatform(self) -> _FakePlatform:  # noqa: N802
-        return self._platform_cls()
-
-    def Prepend(self, CXXFLAGS: list[str]) -> None:  # noqa: N802, N803
-        self.prepended = CXXFLAGS
-
-
-def _fake_cxx(
-    tmp_path: Path,
-    fail: bool = False,
-    fail_msg: str | None = None,
-    reject_pch: bool = False,
-    probe_exit: int = 0,
-) -> Path:
-    """A compiler stand-in that records its argv and writes the -o target.
-
-    With reject_pch it builds the .gch fine but, like GCC 10 on macOS arm64,
-    warns on any consuming compile that the .gch cannot be loaded; probe_exit
-    sets the exit code of non-header compiles (the load probe).
-    """
-    cxx = tmp_path / "fake-gxx"
-    body = (
-        'printf -- ---call---\\\\n >> "$0.argv"; printf \'%s\\n\' "$@" >> "$0.argv"\n'
-    )
-    if fail:
-        body += f"echo {fail_msg or 'boom'} >&2\nexit 1\n"
-    else:
-        # Only the c++-header compile has a -o; the load probe has none
-        body += 'out=""; prev=""; mf=0; dep=0\nfor a in "$@"; do [ "$prev" = "-o" ] && out="$a"; prev="$a"; [ "$a" = "-MF" ] && mf=1; case "$a" in -M|-MM|-MD|-MMD) dep=1;; esac; done\n'
-        # Real cc1plus rejects -MF without a dependency flag
-        body += 'if [ "$mf" = 1 ] && [ "$dep" = 0 ]; then echo "cc1plus: error: to generate dependencies you must specify either \x27-M\x27 or \x27-MM\x27" >&2; exit 1; fi\n'
-        body += '[ -n "$out" ] && echo gch > "$out"\n'
-        if reject_pch:
-            body += 'case " $* " in *c++-header*) ;; *) echo "warning: esphome_pch.h.gch: had text segment at different address" >&2;; esac\n'
-        body += f'case " $* " in *c++-header*) exit 0;; *) exit {probe_exit};; esac\n'
-    cxx.write_text("#!/bin/sh\n" + body)
-    cxx.chmod(cxx.stat().st_mode | stat.S_IEXEC)
-    return cxx
-
-
-def _run_script(
-    tmp_path: Path,
-    flags: list[str] | None = None,
-    fail: bool = False,
-    fail_msg: str | None = None,
-    reject_pch: bool = False,
-    probe_exit: int = 0,
-    missing_cxx: bool = False,
-    env_vars: dict[str, str] | None = None,
-    name: str = "dev",
-    platform_cls: type[_FakePlatform] = _FakePlatform,
-) -> _FakeSConsEnv:
-    proj = tmp_path / name
-    src = proj / "src"
-    (src / "esphome" / "core").mkdir(parents=True, exist_ok=True)
-    (src / "esphome" / "core" / "defines.h").write_text("#define USE_X\n")
-    cxx = _fake_cxx(
-        tmp_path,
-        fail=fail,
-        fail_msg=fail_msg,
-        reject_pch=reject_pch,
-        probe_exit=probe_exit,
-    )
-    if missing_cxx:
-        cxx = tmp_path / "no-such-gxx"
-    args = (proj, src, str(cxx), flags or ["-DX=1"], platform_cls)
-    # Distinct objects: the -include flags must land on projenv only
-    global_env = _FakeSConsEnv(*args)
-    projenv = _FakeSConsEnv(*args)
-    projenv.global_env = global_env
-    source = _SCRIPT.read_text()
-    with patch.dict(os.environ, env_vars or {}, clear=True):
-        exec(  # noqa: S102
-            compile(source, "pch.py", "exec"),
-            {"Import": lambda *_names: None, "env": global_env, "projenv": projenv},
-        )
-    return projenv
-
-
-def test_pch_script_builds_and_prepends_relative_include(tmp_path: Path) -> None:
-    scons_env = _run_script(tmp_path)
-    proj = tmp_path / "dev"
-    assert (proj / "esphome_pch.h").read_text().endswith('"esphome/core/defines.h"\n')
-    assert (proj / "esphome_pch.h.gch").is_file()
-    assert len((proj / "esphome_pch.h.gch.sum").read_text().strip()) == 64
-    # Relative include: an absolute path would poison ccache keys
-    assert scons_env.prepended == [
-        "-Winvalid-pch",
-        "-Wno-error=invalid-pch",
-        "-include",
-        "esphome_pch.h",
-    ]
-    # In production projenv["ENV"] aliases os.environ; only the -include
-    # flags are genuinely scoped to projenv (src compiles)
-    assert scons_env["ENV"]["CCACHE_SLOPPINESS"] == "pch_defines,time_macros"
-    assert scons_env["ENV"]["CCACHE_PCH_EXTSUM"] == "true"
-    assert scons_env.global_env.prepended == []
-
-
-def test_pch_script_preserves_spaced_flag_elements(tmp_path: Path) -> None:
-    """One SCons element stays one compiler argv; -include pairs are
-    stripped from the .gch compile."""
-    spaced = tmp_path / "My Configs"
-    spaced.mkdir()
-    (tmp_path / "dev" / "src").mkdir(parents=True, exist_ok=True)
-    (tmp_path / "dev" / "src" / "other.h").write_text("")
-    flags = ['-DUSB_PRODUCT=\\"Pico 2W\\"', "-I", str(spaced), "-include", "other.h"]
-    _run_script(tmp_path, flags=flags)
-    calls = (tmp_path / "fake-gxx.argv").read_text().split("---call---\n")
-    gch_call = next(c for c in calls if "c++-header" in c).splitlines()
-    assert '-DUSB_PRODUCT="Pico 2W"' in gch_call
-    assert str(spaced) in gch_call
-    assert "-include" not in gch_call
-    # The stripped src-resolvable -include is folded into the prefix header
-    pch = (tmp_path / "dev" / "esphome_pch.h").read_text()
-    assert pch.splitlines()[0] == '#include "other.h"'
-
-
-def test_pch_script_folds_joined_force_include_spelling(tmp_path: Path) -> None:
-    """-includefoo.h folds like the separated form, matching the native path."""
-    (tmp_path / "dev" / "src").mkdir(parents=True, exist_ok=True)
-    (tmp_path / "dev" / "src" / "other.h").write_text("")
-    _run_script(tmp_path, flags=["-DX=1", "-includeother.h"])
-    pch = (tmp_path / "dev" / "esphome_pch.h").read_text()
-    assert pch.splitlines()[0] == '#include "other.h"'
-
-
-def test_pch_script_leaves_absolute_force_includes_unfolded(
-    tmp_path: Path,
-) -> None:
-    """An absolute -include resolves through src_dir / name; it must still
-    stay consumer-only or the host path enters the .sum."""
-    outside = tmp_path / "outside.h"
-    outside.write_text("")
-    _run_script(tmp_path, flags=["-DX=1", "-include", str(outside)])
-    pch = (tmp_path / "dev" / "esphome_pch.h").read_text()
-    assert "outside.h" not in pch
-
-
-def test_pch_script_leaves_non_src_force_includes_unfolded(
-    tmp_path: Path, capsys: pytest.CaptureFixture[str]
-) -> None:
-    """A user -include outside src/ must not enter the prefix header:
-    consumers keep their own copy, so folding an unguarded header would
-    include it twice."""
-    _run_script(tmp_path, flags=["-DX=1", "-include", "user_extra.h"])
-    pch = (tmp_path / "dev" / "esphome_pch.h").read_text()
-    assert "user_extra.h" not in pch
-    assert pch.splitlines()[-1] == '#include "esphome/core/defines.h"'
-    assert "not precompiling non-src force-includes" in capsys.readouterr().out
-
-
-def test_pch_script_sum_is_device_independent(tmp_path: Path) -> None:
-    """Regression: identical configs in different dirs share cache keys."""
-    sums = []
-    for name in ("dev_a", "dev_b"):
-        proj = tmp_path / name
-        _run_script(
-            tmp_path,
-            flags=["-DX=1", "-I", str(proj / "include")],
-            env_vars={"CCACHE_BASEDIR": str(proj)},
-            name=name,
-        )
-        sums.append((proj / "esphome_pch.h.gch.sum").read_text())
-        (tmp_path / "fake-gxx").unlink()
-        (tmp_path / "fake-gxx.argv").unlink(missing_ok=True)
-    assert sums[0] == sums[1]
-
-
-def test_pch_script_transient_compiler_failure_does_not_latch(
-    tmp_path: Path,
-) -> None:
-    """ENOSPC-style failures clear on their own; no .failed marker."""
-    scons_env = _run_script(tmp_path, fail=True, fail_msg="No space left on device")
-    proj = tmp_path / "dev"
-    assert not (proj / "esphome_pch.h.gch.failed").exists()
-    assert scons_env.prepended == []
-
-
-def test_pch_script_failure_marker_suppresses_retry(
-    tmp_path: Path, capsys: pytest.CaptureFixture[str]
-) -> None:
-    scons_env = _run_script(tmp_path, fail=True)
-    proj = tmp_path / "dev"
-    assert (proj / "esphome_pch.h.gch.failed").is_file()
-    assert not (proj / "esphome_pch.h.gch.sum").exists()
-    assert scons_env.prepended == []
-    # Second run: same checksum, no compile attempt, but says so
-    attempts = (tmp_path / "fake-gxx.argv").read_text().count("c++-header")
-    _run_script(tmp_path, fail=True)
-    out = capsys.readouterr().out
-    assert (tmp_path / "fake-gxx.argv").read_text().count("c++-header") == attempts
-    assert "delete esphome_pch.h.gch.failed to retry" in out
-
-
-def test_pch_script_probe_rejection_falls_back(
-    tmp_path: Path, capsys: pytest.CaptureFixture[str]
-) -> None:
-    """A toolchain that cannot load its own .gch (GCC 10 on macOS arm64)
-    must not leave consumers paying for a pch every compile rejects."""
-    scons_env = _run_script(tmp_path, reject_pch=True)
-    proj = tmp_path / "dev"
-    assert not (proj / "esphome_pch.h.gch").exists()
-    assert not (proj / "esphome_pch.h.gch.sum").exists()
-    assert (proj / "esphome_pch.h.gch.failed").is_file()
-    assert scons_env.prepended == []
-    assert "toolchain cannot load the pch" in capsys.readouterr().out
-
-
-def test_pch_script_spawn_failure_is_transient(
-    tmp_path: Path, capsys: pytest.CaptureFixture[str]
-) -> None:
-    """A spawn failure must not latch a .failed marker (matches espidf)."""
-    scons_env = _run_script(tmp_path, missing_cxx=True)
-    proj = tmp_path / "dev"
-    assert not (proj / "esphome_pch.h.gch.failed").exists()
-    assert not (proj / "esphome_pch.h.gch.sum").exists()
-    assert scons_env.prepended == []
-    assert "did not run" in capsys.readouterr().out
-
-
-def test_pch_script_probe_nonzero_exit_falls_back(tmp_path: Path) -> None:
-    """A probe failure whose stderr never mentions .gch must still count."""
-    scons_env = _run_script(tmp_path, probe_exit=1)
-    proj = tmp_path / "dev"
-    assert not (proj / "esphome_pch.h.gch").exists()
-    assert (proj / "esphome_pch.h.gch.failed").is_file()
-    assert scons_env.prepended == []
-
-
-def test_pch_script_unresolved_package_version_skips_pch(tmp_path: Path) -> None:
-    """A KeyError for an installed package is unresolved identity, not absence."""
-    scons_env = _run_script(tmp_path, platform_cls=_UnresolvedPlatform)
-    assert not (tmp_path / "dev" / "esphome_pch.h.gch").exists()
-    assert scons_env.prepended == []
-
-
-def test_pch_script_package_version_error_skips_pch(tmp_path: Path) -> None:
-    """Without trustworthy package identity a stale .gch could survive an
-    upgrade, so the script must not build one at all."""
-    scons_env = _run_script(tmp_path, platform_cls=_BrokenPlatform)
-    proj = tmp_path / "dev"
-    assert not (proj / "esphome_pch.h.gch").exists()
-    assert scons_env.prepended == []
-
-
-def test_pch_script_corrupt_sidecar_reads_as_stale(tmp_path: Path) -> None:
-    """A truncated/corrupt .failed marker must not disable the pch forever."""
-    _run_script(tmp_path, fail=True)
-    proj = tmp_path / "dev"
-    (proj / "esphome_pch.h.gch.failed").write_bytes(b"\xff\xfe corrupt")
-    _run_script(tmp_path)
-    assert (proj / "esphome_pch.h.gch").is_file()
-    assert (proj / "esphome_pch.h.gch.sum").is_file()
-
-
-def test_pch_script_rebuilds_when_header_missing(tmp_path: Path) -> None:
-    _run_script(tmp_path)
-    proj = tmp_path / "dev"
-    (proj / "esphome_pch.h").unlink()
-    _run_script(tmp_path)
-    assert (proj / "esphome_pch.h").is_file()
-
-
-def test_copy_pch_script(tmp_path: Path) -> None:
-    from esphome.core import CORE
-
-    CORE.build_path = tmp_path
-    toolchain.copy_pch_script()
-    assert (tmp_path / "pch.py").read_text() == _SCRIPT.read_text()
-
-
-def test_pch_script_unions_user_sloppiness(
-    tmp_path: Path, capsys: pytest.CaptureFixture[str]
-) -> None:
-    """A user CCACHE_SLOPPINESS without the pch tokens gets them unioned on,
-    mirroring ccache_pch_env, or every src TU is a permanent miss."""
-    scons_env = _run_script(tmp_path, env_vars={"CCACHE_SLOPPINESS": "locale"})
-    assert scons_env["ENV"]["CCACHE_SLOPPINESS"] == "locale,pch_defines,time_macros"
-    assert "adding pch_defines,time_macros" in capsys.readouterr().out
-
-
-def test_pch_script_unmodelable_flag_skips_pch(
-    tmp_path: Path, capsys: pytest.CaptureFixture[str]
-) -> None:
-    """Unbalanced quotes and multi-token elements cannot be reproduced as
-    one argv; the pch is skipped rather than built with diverging flags."""
-    for bad in ("-DFOO='bar", "-DA=1\t-DB=2"):
-        scons_env = _run_script(tmp_path, flags=["-DX=1", bad])
-        assert scons_env.prepended == []
-        assert not (tmp_path / "dev" / "esphome_pch.h.gch").exists()
-    assert "unmodelable flag" in capsys.readouterr().out
-
-
-@pytest.mark.skipif(
-    getattr(os, "geteuid", lambda: -1)() == 0, reason="root ignores file modes"
-)
-def test_pch_script_unlistable_include_dir_skips_pch(
-    tmp_path: Path, capsys: pytest.CaptureFixture[str]
-) -> None:
-    """An unlistable subtree must not silently drop out of the digest."""
-    proj = tmp_path / "dev"
-    override = proj / "lwip_override"
-    hidden = override / "hidden"
-    hidden.mkdir(parents=True)
-    (hidden / "gen.h").write_text("")
-    hidden.chmod(0)
-    try:
-        scons_env = _run_script(tmp_path, flags=["-DX=1", "-I", str(override)])
-    finally:
-        hidden.chmod(0o755)
-    assert scons_env.prepended == []
-    assert "skipping precompiled header" in capsys.readouterr().out
-
-
-def test_pch_script_nobuild_without_projenv_is_noop(tmp_path: Path) -> None:
-    """-t nobuild never exports projenv; the script must not abort."""
-    proj = tmp_path / "dev"
-    (proj / "src").mkdir(parents=True)
-
-    def strict_import(*names: str) -> None:
-        if "projenv" in names:
-            raise RuntimeError("Import of non-existent variable 'projenv'")
-
-    env = _FakeSConsEnv(proj, proj / "src", "g++", ["-DX=1"])
-    exec(  # noqa: S102
-        compile(_SCRIPT.read_text(), "pch.py", "exec"),
-        {"Import": strict_import, "env": env},
-    )
-    assert not (proj / "esphome_pch.h").exists()
-
-
-def test_pch_script_ignores_library_trees_and_non_headers(tmp_path: Path) -> None:
-    """.piolibdeps and non-header files must not enter the digest (or be
-    read at all); package versions already cover library identity."""
-    proj = tmp_path / "dev"
-    libdeps = proj / ".piolibdeps" / "lib" / "src"
-    libdeps.mkdir(parents=True)
-    (libdeps / "lib.h").write_text("#define A 1\n")
-    override = proj / "lwip_override"
-    override.mkdir(parents=True)
-    (override / "lwipopts.h").write_text("#define TCP_MSS 1460\n")
-    (override / "notes.txt").write_text("v1\n")
-    flags = ["-DX=1", "-I", str(libdeps), "-I", str(override)]
-    _run_script(tmp_path, flags=flags)
-    first = (proj / "esphome_pch.h.gch.sum").read_text()
-    (libdeps / "lib.h").write_text("#define A 2\n")
-    (override / "notes.txt").write_text("v2\n")
-    (tmp_path / "fake-gxx.argv").unlink(missing_ok=True)
-    _run_script(tmp_path, flags=flags)
-    assert (proj / "esphome_pch.h.gch.sum").read_text() == first
-
-
-def test_pch_script_hashes_project_local_include_dirs(tmp_path: Path) -> None:
-    """Generated headers in project-local -I dirs (e.g. rp2's lwip_override)
-    must invalidate the checksum when they change."""
-    proj = tmp_path / "dev"
-    override = proj / "lwip_override"
-    override.mkdir(parents=True)
-    (override / "lwipopts.h").write_text("#define TCP_MSS 1460\n")
-    flags = ["-DX=1", "-I", str(override)]
-    _run_script(tmp_path, flags=flags)
-    first = (proj / "esphome_pch.h.gch.sum").read_text()
-    (override / "lwipopts.h").write_text("#define TCP_MSS 536\n")
-    (tmp_path / "fake-gxx.argv").unlink(missing_ok=True)
-    _run_script(tmp_path, flags=flags)
-    assert (proj / "esphome_pch.h.gch.sum").read_text() != first
-
-
-@pytest.mark.skipif(
-    getattr(os, "geteuid", lambda: -1)() == 0, reason="root ignores file modes"
-)
-def test_pch_script_unreadable_local_header_skips_pch(
-    tmp_path: Path, capsys: pytest.CaptureFixture[str]
-) -> None:
-    """An unreadable generated header means unknown identity: no pch."""
-    proj = tmp_path / "dev"
-    override = proj / "lwip_override"
-    override.mkdir(parents=True)
-    secret = override / "lwipopts.h"
-    secret.write_text("#define TCP_MSS 1460\n")
-    secret.chmod(0)
-    scons_env = _run_script(tmp_path, flags=["-DX=1", "-I", str(override)])
-    assert not (proj / "esphome_pch.h.gch.sum").exists()
-    assert scons_env.prepended == []
-    assert "skipping precompiled header" in capsys.readouterr().out

tests/unit_tests/test_writer.py

@@ -516,13 +516,10 @@ def test_clean_build(
     dependencies_lock = tmp_path / "dependencies.lock"
     dependencies_lock.write_text("lock file")
 
-    # idedata caches live under the data dir, not the build path; the
-    # .arduino.json variant is the native esp8266 toolchain's.
+    # idedata cache lives under the data dir, not the build path.
     idedata_cache = tmp_path / "idedata" / "test.json"
     idedata_cache.parent.mkdir()
     idedata_cache.write_text("{}")
-    arduino_idedata_cache = tmp_path / "idedata" / "test.arduino.json"
-    arduino_idedata_cache.write_text("{}")
 
     # Native ESP-IDF toolchain artifacts.
     idf_build_dir = tmp_path / "build"
@@ -583,7 +580,6 @@ def test_clean_build(
     assert not piolibdeps_dir.exists()
     assert not dependencies_lock.exists()
     assert not idedata_cache.exists()
-    assert not arduino_idedata_cache.exists()
     assert not idf_build_dir.exists()
     assert not managed_components_dir.exists()
     assert not pio_components_dir.exists()
@@ -677,32 +673,6 @@ def test_clean_build_partial_exists(
     assert "dependencies.lock" not in caplog.text
 
 
-@patch("esphome.writer.CORE")
-def test_clean_build_partial_removes_pch_artifacts(
-    mock_core: MagicMock,
-    tmp_path: Path,
-) -> None:
-    """The PlatformIO pch sidecars live at the project root and must go in
-    a partial clean, like the native backend's under .pioenvs."""
-    names = (
-        "esphome_pch.h",
-        "esphome_pch.h.gch",
-        "esphome_pch.h.gch.sum",
-        "esphome_pch.h.gch.failed",
-    )
-    for name in names:
-        (tmp_path / name).write_text("x")
-    mock_core.relative_pioenvs_path.return_value = tmp_path / ".pioenvs"
-    mock_core.relative_piolibdeps_path.return_value = tmp_path / ".piolibdeps"
-    mock_core.relative_build_path.side_effect = lambda name: tmp_path / name
-    mock_core.relative_internal_path.side_effect = tmp_path.joinpath
-
-    clean_build()
-
-    for name in names:
-        assert not (tmp_path / name).exists()
-
-
 @patch("esphome.writer.CORE")
 def test_clean_build_nothing_exists(
     mock_core: MagicMock,