cache

.github/workflows/ci.yml

@@ -192,6 +192,11 @@ jobs:
         with:
           python-version: ${{ env.DEFAULT_PYTHON }}
           cache-key: ${{ needs.common.outputs.cache-key }}
+      - name: Restore components graph cache
+        uses: actions/cache/restore@0057852bfaa89a56745cba8c7296529d2fc39830 # v4.3.0
+        with:
+          path: .temp/components_graph.json
+          key: components-graph-${{ hashFiles('esphome/components/**/__init__.py') }}
       - name: Determine which tests to run
         id: determine
         env:
@@ -216,6 +221,12 @@ jobs:
           echo "cpp-unit-tests-run-all=$(echo "$output" | jq -r '.cpp_unit_tests_run_all')" >> $GITHUB_OUTPUT
           echo "cpp-unit-tests-components=$(echo "$output" | jq -c '.cpp_unit_tests_components')" >> $GITHUB_OUTPUT
           echo "component-test-batches=$(echo "$output" | jq -c '.component_test_batches')" >> $GITHUB_OUTPUT
+      - name: Save components graph cache
+        if: github.ref == 'refs/heads/dev'
+        uses: actions/cache/save@0057852bfaa89a56745cba8c7296529d2fc39830 # v4.3.0
+        with:
+          path: .temp/components_graph.json
+          key: components-graph-${{ hashFiles('esphome/components/**/__init__.py') }}
 
   integration-tests:
     name: Run integration tests

script/helpers.py

@@ -52,6 +52,10 @@ BASE_BUS_COMPONENTS = {
     "remote_receiver",
 }
 
+# Cache version for components graph
+# Increment this when the cache format or graph building logic changes
+COMPONENTS_GRAPH_CACHE_VERSION = 1
+
 
 def parse_list_components_output(output: str) -> list[str]:
     """Parse the output from list-components.py script.
@@ -752,20 +756,69 @@ def resolve_auto_load(
     return auto_load()
 
 
+def _get_components_graph_cache_key() -> str:
+    """Generate cache key based on all component __init__.py file hashes.
+
+    Uses git ls-files with sha1 hashes to generate a stable cache key that works
+    across different machines and CI runs. This is faster and more reliable than
+    reading file contents or using modification times.
+
+    Returns:
+        SHA256 hex string uniquely identifying the current component state
+    """
+    import hashlib
+
+    # Use git ls-files -s to get sha1 hashes of all component __init__.py files
+    # Format: <mode> <sha1> <stage> <path>
+    # This is fast and works consistently across CI and local dev
+    cmd = ["git", "ls-files", "-s", "esphome/components/**/__init__.py"]
+    result = subprocess.run(
+        cmd, capture_output=True, text=True, check=True, cwd=root_path
+    )
+
+    # Hash the git output (includes file paths and their sha1 hashes)
+    # This changes only when component __init__.py files actually change
+    hasher = hashlib.sha256()
+    hasher.update(result.stdout.encode())
+
+    return hasher.hexdigest()
+
+
 def create_components_graph() -> dict[str, list[str]]:
-    """Create a graph of component dependencies.
+    """Create a graph of component dependencies (cached).
+
+    This function is expensive (5-6 seconds) because it imports all ESPHome components
+    to extract their DEPENDENCIES and AUTO_LOAD metadata. The result is cached based
+    on component file modification times, so unchanged components don't trigger a rebuild.
 
     Returns:
         Dictionary mapping parent components to their children (dependencies)
     """
-    from pathlib import Path
+    # Check cache first - use fixed filename since GitHub Actions cache doesn't support wildcards
+    cache_file = Path(temp_folder) / "components_graph.json"
+
+    if cache_file.exists():
+        try:
+            cached_data = json.loads(cache_file.read_text())
+        except (OSError, json.JSONDecodeError):
+            # Cache file corrupted or unreadable, rebuild
+            pass
+        else:
+            # Verify cache version matches
+            if cached_data.get("_version") == COMPONENTS_GRAPH_CACHE_VERSION:
+                # Verify cache is for current component state
+                cache_key = _get_components_graph_cache_key()
+                if cached_data.get("_cache_key") == cache_key:
+                    return cached_data.get("graph", {})
+                # Cache key mismatch - stale cache, rebuild
+            # Cache version mismatch - incompatible format, rebuild
 
     from esphome import const
     from esphome.core import CORE
     from esphome.loader import ComponentManifest, get_component, get_platform
 
     # The root directory of the repo
-    root = Path(__file__).parent.parent
+    root = Path(root_path)
     components_dir = root / ESPHOME_COMPONENTS_PATH
     # Fake some directory so that get_component works
     CORE.config_path = root
@@ -842,6 +895,15 @@ def create_components_graph() -> dict[str, list[str]]:
             # restore config
             CORE.data[KEY_CORE] = TARGET_CONFIGURATIONS[0]
 
+    # Save to cache with version and cache key for validation
+    cache_data = {
+        "_version": COMPONENTS_GRAPH_CACHE_VERSION,
+        "_cache_key": _get_components_graph_cache_key(),
+        "graph": components_graph,
+    }
+    cache_file.parent.mkdir(exist_ok=True)
+    cache_file.write_text(json.dumps(cache_data))
+
     return components_graph