[ci] Share a cached native ESP-IDF install across clang-tidy and build jobs (#16841)

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

@@ -0,0 +1,46 @@
+name: Cache ESP-IDF
+description: >
+  Resolve the pinned ESP-IDF version and cache the native ESP-IDF install
+  (toolchains + source) at ~/.esphome-idf. Every job that installs ESP-IDF
+  natively (clang-tidy for IDF/Arduino and the native-IDF component build)
+  shares one cache, since the install is identical (ESPHOME_IDF_DEFAULT_TARGETS
+  defaults to "all", so all toolchains are present regardless of the chip).
+  Callers must set env ESPHOME_ESP_IDF_PREFIX: ~/.esphome-idf and have the
+  Python venv already restored.
+inputs:
+  framework:
+    description: 'Which pinned IDF version to key on: "espidf" (recommended) or "arduino".'
+    default: espidf
+runs:
+  using: composite
+  steps:
+    - name: Resolve ESP-IDF version for cache key
+      # The native-IDF version is pinned in code, not in any file that feeds the
+      # other cache keys, so resolve it explicitly. Keying on it means the cache
+      # invalidates on a version bump (actions/cache never overwrites a key).
+      id: version
+      shell: bash
+      run: |
+        . venv/bin/activate
+        if [ "${{ inputs.framework }}" = "arduino" ]; then
+          version=$(python -c 'from esphome.components.esp32 import ARDUINO_FRAMEWORK_VERSION_LOOKUP as A, ARDUINO_IDF_VERSION_LOOKUP as L; print(L[A["recommended"]])')
+        else
+          version=$(python -c 'from esphome.components.esp32 import ESP_IDF_FRAMEWORK_VERSION_LOOKUP as L; print(L["recommended"])')
+        fi
+        echo "version=$version" >> "$GITHUB_OUTPUT"
+    # Mirror the adjacent PlatformIO cache: only dev-branch runs write the
+    # shared cache (so it lives in the default-branch scope readable by all
+    # PRs), and PRs are restore-only -- they never push multi-GB artifacts into
+    # their own scope / the repo quota (e.g. on a version-bump PR).
+    - name: Cache ESP-IDF install (write on dev)
+      if: github.ref == 'refs/heads/dev'
+      uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
+      with:
+        path: ~/.esphome-idf
+        key: ${{ runner.os }}-esphome-idf-${{ steps.version.outputs.version }}
+    - name: Cache ESP-IDF install (restore-only off dev)
+      if: github.ref != 'refs/heads/dev'
+      uses: actions/cache/restore@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
+      with:
+        path: ~/.esphome-idf
+        key: ${{ runner.os }}-esphome-idf-${{ steps.version.outputs.version }}

.github/workflows/ci.yml

@@ -472,6 +472,8 @@ jobs:
     if: needs.determine-jobs.outputs.clang-tidy == 'true'
     env:
       GH_TOKEN: ${{ github.token }}
+      # esp32-arduino-tidy installs ESP-IDF natively; share the native IDF cache.
+      ESPHOME_ESP_IDF_PREFIX: ~/.esphome-idf
     strategy:
       fail-fast: false
       max-parallel: 2
@@ -484,6 +486,7 @@ jobs:
           - id: clang-tidy
             name: Run script/clang-tidy for ESP32 Arduino
             options: --environment esp32-arduino-tidy --grep USE_ARDUINO
+            cache_idf: true
           - id: clang-tidy
             name: Run script/clang-tidy for ZEPHYR
             options: --environment nrf52-tidy --grep USE_ZEPHYR --grep USE_NRF52
@@ -517,6 +520,13 @@ jobs:
           path: ~/.platformio
           key: platformio-${{ matrix.pio_cache_key }}-${{ hashFiles('platformio.ini') }}
 
+      - name: Cache ESP-IDF install
+        # Shared with the IDF tidy + native-IDF build jobs (same install).
+        if: matrix.cache_idf
+        uses: ./.github/actions/cache-esp-idf
+        with:
+          framework: arduino
+
       - name: Register problem matchers
         run: |
           echo "::add-matcher::.github/workflows/matchers/gcc.json"
@@ -568,6 +578,8 @@ jobs:
     if: needs.determine-jobs.outputs.clang-tidy-mode == 'nosplit'
     env:
       GH_TOKEN: ${{ github.token }}
+      # esp32-idf-tidy installs ESP-IDF natively; share the native IDF cache.
+      ESPHOME_ESP_IDF_PREFIX: ~/.esphome-idf
     steps:
       - name: Check out code from GitHub
         uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
@@ -581,6 +593,10 @@ jobs:
           python-version: ${{ env.DEFAULT_PYTHON }}
           cache-key: ${{ needs.common.outputs.cache-key }}
 
+      - name: Cache ESP-IDF install
+        # Shared with the Arduino tidy + native-IDF build jobs (same install).
+        uses: ./.github/actions/cache-esp-idf
+
       - name: Register problem matchers
         run: |
           echo "::add-matcher::.github/workflows/matchers/gcc.json"
@@ -631,6 +647,8 @@ jobs:
     if: needs.determine-jobs.outputs.clang-tidy-mode == 'split'
     env:
       GH_TOKEN: ${{ github.token }}
+      # esp32-idf-tidy installs ESP-IDF natively; share the native IDF cache.
+      ESPHOME_ESP_IDF_PREFIX: ~/.esphome-idf
     strategy:
       fail-fast: false
       max-parallel: 3
@@ -659,6 +677,10 @@ jobs:
           python-version: ${{ env.DEFAULT_PYTHON }}
           cache-key: ${{ needs.common.outputs.cache-key }}
 
+      - name: Cache ESP-IDF install
+        # Shared with the Arduino tidy + native-IDF build jobs (same install).
+        uses: ./.github/actions/cache-esp-idf
+
       - name: Register problem matchers
         run: |
           echo "::add-matcher::.github/workflows/matchers/gcc.json"
@@ -785,7 +807,7 @@ jobs:
           fi
           echo ""
 
-          # Show disk space before validation (after bind mounts setup)
+          # Show disk space before validation
           echo "Disk space before config validation:"
           df -h
           echo ""
@@ -861,33 +883,20 @@ jobs:
           python-version: ${{ env.DEFAULT_PYTHON }}
           cache-key: ${{ needs.common.outputs.cache-key }}
 
-      - name: Cache ESPHome
+      - name: Prepare build storage on /mnt
-        uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
+        # Bind-mount the larger /mnt disk over the IDF install + build dirs BEFORE
-        with:
+        # restoring the cache, so the ~4.5GB restore lands on the roomier volume
-          path: ~/.esphome-idf
+        # instead of being shadowed by a mount set up later in the run step.
-          key: ${{ runner.os }}-esphome-${{ needs.common.outputs.cache-key }}
-
-      - name: Run native ESP-IDF compile test
         run: |
-          . venv/bin/activate
-
-          # Check if /mnt has more free space than / before bind mounting
-          # Extract available space in KB for comparison
           root_avail=$(df -k / | awk 'NR==2 {print $4}')
           mnt_avail=$(df -k /mnt 2>/dev/null | awk 'NR==2 {print $4}')
-
           echo "Available space: / has ${root_avail}KB, /mnt has ${mnt_avail}KB"
-
-          # Only use /mnt if it has more space than /
           if [ -n "$mnt_avail" ] && [ "$mnt_avail" -gt "$root_avail" ]; then
             echo "Using /mnt for build files (more space available)"
-            # Bind mount PlatformIO directory to /mnt (tools, packages, build cache all go there)
             sudo mkdir -p /mnt/esphome-idf
             sudo chown $USER:$USER /mnt/esphome-idf
             mkdir -p ~/.esphome-idf
             sudo mount --bind /mnt/esphome-idf ~/.esphome-idf
-
-            # Bind mount test build directory to /mnt
             sudo mkdir -p /mnt/test_build_components_build
             sudo chown $USER:$USER /mnt/test_build_components_build
             mkdir -p tests/test_build_components/build
@@ -896,10 +905,19 @@ jobs:
             echo "Using / for build files (more space available than /mnt or /mnt unavailable)"
           fi
 
+      - name: Cache ESP-IDF install
+        # Shared with the IDF/Arduino clang-tidy jobs (same install); restores
+        # into the /mnt bind-mount prepared above when present.
+        uses: ./.github/actions/cache-esp-idf
+
+      - name: Run native ESP-IDF compile test
+        run: |
+          . venv/bin/activate
+
           echo "Testing components: $TEST_COMPONENTS"
           echo ""
 
-          # Show disk space before validation (after bind mounts setup)
+          # Show disk space before validation
           echo "Disk space before config validation:"
           df -h
           echo ""