Memoize the skip decision, gate the serial rejection, fix a stale comment

The macro drift warning now prints once per run; the serial --device
rejection only applies where the flag does, so other platforms keep
their ignore and warn behavior; the added lines comment points at
idf_macro_matches instead of a removed module.

esphome/__main__.py

@@ -1770,10 +1770,14 @@ def command_logs(args: ArgsProtocol, config: ConfigType) -> int | None:
 
 
 def command_run(args: ArgsProtocol, config: ConfigType) -> int | None:
-    if CORE.skip_bootloader and any(
-        device.startswith(("/dev/", "COM")) for device in (args.device or [])
+    if (
+        CORE.skip_bootloader
+        and CORE.is_esp32
+        and CORE.using_toolchain_esp_idf
+        and any(device.startswith(("/dev/", "COM")) for device in (args.device or []))
     ):
         # Fail before the compile: the result could never flash over serial.
+        # Elsewhere the flag is ignored, so serial stays fine there.
         _LOGGER.error("--skip-bootloader builds cannot be flashed over serial")
         return 1
     exit_code = write_cpp(config)

esphome/build_gen/espidf.py

@@ -116,8 +116,8 @@ if(ESPHOME_SKIP_BOOTLOADER)
 endif()
 """
 
-# The lines the override adds to IDF's macro; the staleness tripwire in
-# esphome.espidf.bootloader strips them before comparing with the live macro.
+# The lines the override adds to IDF's macro; idf_macro_matches() below
+# strips them before comparing with the live macro.
 BOOTLOADER_OVERRIDE_ADDED_LINES = (
     'set(CONFIG_APP_BUILD_BOOTLOADER "")',
     "idf_build_get_property(idf_target IDF_TARGET)",

esphome/espidf/toolchain.py

@@ -40,6 +40,7 @@ class _CacheData:
     paths: dict[str, tuple] = field(default_factory=dict)
     env: dict[str, dict[str, str]] = field(default_factory=dict)
     cmake_output: dict[Path, str] = field(default_factory=dict)
+    skip_bootloader: bool | None = None
     cmake_tools: dict[Path, dict[str, Path]] = field(default_factory=dict)
 
 
@@ -298,7 +299,14 @@ def tree_skips_bootloader(build_dir: Path) -> bool:
 
 
 def _skip_bootloader() -> bool:
-    """Whether this tree should not build a bootloader at all."""
+    """Whether this tree should not build a bootloader at all; per-run memo."""
+    cache = _cache()
+    if cache.skip_bootloader is None:
+        cache.skip_bootloader = _compute_skip_bootloader()
+    return cache.skip_bootloader
+
+
+def _compute_skip_bootloader() -> bool:
     if not CORE.skip_bootloader:
         return False
     from esphome.build_gen.espidf import idf_macro_matches

tests/unit_tests/test_espidf_toolchain.py

@@ -1118,17 +1118,21 @@ def test_skip_bootloader_requires_flag_and_matching_macro(
 
     assert toolchain._skip_bootloader() is False
     CORE.skip_bootloader = True
+    toolchain._cache().skip_bootloader = None  # decision is memoized per run
     with (
         patch.object(toolchain, "_get_idf_path", return_value=Path("/idf")),
         patch.object(build_gen, "idf_macro_matches", return_value=True),
     ):
         assert toolchain._skip_bootloader() is True
+    toolchain._cache().skip_bootloader = None
     with (
         patch.object(toolchain, "_get_idf_path", return_value=Path("/idf")),
-        patch.object(build_gen, "idf_macro_matches", return_value=False),
+        patch.object(build_gen, "idf_macro_matches", return_value=False) as mock_match,
         caplog.at_level("WARNING"),
     ):
         assert toolchain._skip_bootloader() is False
+        assert toolchain._skip_bootloader() is False
+    mock_match.assert_called_once()  # the memo also dedupes the warning
     assert "--skip-bootloader ignored" in caplog.text
 
 

tests/unit_tests/test_main.py

@@ -6870,6 +6870,7 @@ def test_command_run_rejects_serial_device_with_skip_bootloader(
     """The compile could never be flashed over serial; fail before it runs."""
     setup_core(platform=PLATFORM_ESP32, tmp_path=tmp_path, name="test")
     CORE.skip_bootloader = True
+    CORE.toolchain = Toolchain.ESP_IDF
     args = MockArgs(device=["/dev/ttyUSB0"])
     with patch("esphome.__main__.write_cpp") as mock_write:
         assert command_run(args, {}) == 1