Merge branch 'esp8266-native-toolchain-plumbing' into esp8266-native-build-infra

esphome/__main__.py

@@ -2734,14 +2734,15 @@ def run_esphome(argv):
     # Skipped when -s overrides are passed, since the cache was written
     # against the previous substitution set.
     config: ConfigType | None = None
-    cache_eligible = (
-        args.command in ("upload", "logs")
-        and not command_line_substitutions
-        # An explicit CLI toolchain must run the per-platform validators;
-        # the cache was validated under whatever the last compile used
-        and args.toolchain is None
+    cache_write_eligible = (
+        args.command in ("upload", "logs") and not command_line_substitutions
     )
-    if cache_eligible:
+    # An explicit CLI toolchain must run the per-platform validators; the
+    # cache was validated under whatever the last compile used. Only the
+    # read is gated: the refresh below may still save the freshly
+    # validated config, and its sidecar records the resolved toolchain.
+    cache_read_eligible = cache_write_eligible and args.toolchain is None
+    if cache_read_eligible:
         from esphome.compiled_config import load_compiled_config
 
         config = load_compiled_config(conf_path)
@@ -2775,7 +2776,7 @@ def run_esphome(argv):
 
     # Refresh the cache so the next upload/logs hits the fast path
     # instead of re-running read_config.
-    if cache_eligible and cache_missed:
+    if cache_write_eligible and cache_missed:
         from esphome.compiled_config import save_compiled_config_and_sidecar
 
         save_compiled_config_and_sidecar(config)

esphome/config_validation.py

@@ -2537,7 +2537,7 @@ def platformio_version_constraint(value):
     return constraints
 
 
-def check_supported_toolchain(
+def _check_supported_toolchain(
     platform_name: str, supported: tuple[Toolchain, ...]
 ) -> None:
     """Raise when the resolved ``CORE.toolchain`` is not in ``supported``.
@@ -2582,7 +2582,7 @@ def resolve_toolchain(
     def validator(config: ConfigType) -> ConfigType:
         if CORE.toolchain is None:
             CORE.toolchain = config.get(CONF_TOOLCHAIN, default)
-        check_supported_toolchain(platform_name, supported)
+        _check_supported_toolchain(platform_name, supported)
         return config
 
     return validator
@@ -2593,8 +2593,11 @@ def require_platformio_toolchain(
 ) -> Callable[[ConfigType], ConfigType]:
     """Reject a CLI-selected toolchain other than PlatformIO.
 
-    For platforms with only the PlatformIO backend; without this a
-    ``--toolchain`` they cannot serve would silently build with PlatformIO.
+    For platforms with only the PlatformIO backend. Without this a
+    ``--toolchain`` they cannot serve would either build with PlatformIO
+    while claiming another backend, or (for a toolchain another platform
+    owns, like ``esp-idf``) dispatch to a native backend that cannot
+    build this platform at all.
     """
     return resolve_toolchain(
         platform_name, (Toolchain.PLATFORMIO,), Toolchain.PLATFORMIO