Reraise in strict through the IDF flow, funnel the remaining degrade paths, exempt nobuild

esphome/build_gen/espidf.py

@@ -334,6 +334,7 @@ def prepare_pch() -> None:
             "Could not read %s; compiling without the pch: %s", sdkconfig_path, err
         )
         pch.discard_pch(CORE.relative_build_path("build"))
+        pch.pch_degraded(f"sdkconfig unreadable: {err}")
         return
     pch.prepare_pch(
         CORE.relative_build_path("build"),

esphome/build_helpers/pch.py

@@ -407,6 +407,7 @@ def prepare_pch(
                 -result.returncode,
             )
             discard_pch(build_dir)
+            pch_degraded(f"compile killed by signal {-result.returncode}")
             return
         if result.returncode != 0:
             error = result.stderr.strip() or f"exit code {result.returncode}"

esphome/espidf/toolchain.py

@@ -539,6 +539,10 @@ def run_compile(config, verbose: bool) -> int:
         # Discard so a stale .gch can never be consumed
         with suppress(OSError):
             discard_pch()
+        from esphome.build_helpers.pch import pch_strict
+
+        if pch_strict():
+            raise
         _LOGGER.warning(
             "Precompiled header setup failed; compiling without it", exc_info=True
         )

esphome/platformio/pch.py.script

@@ -160,9 +160,10 @@ def _read_stamp(path: Path) -> str:
 
 def _setup_pch() -> bool | None:
     if projenv is None:
-        # Expected under -t nobuild; anything else must leave a trail
+        # Expected under -t nobuild (nothing compiles), so not a degrade
+        # even in strict mode; anything else still leaves a trail
         print(f"ESPHome: projenv unavailable ({_projenv_error}); skipping pch")
-        return
+        return True
     # 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

tests/unit_tests/test_espidf_toolchain.py

@@ -669,6 +669,29 @@ def test_get_core_framework_version_from_core_data():
     assert toolchain._get_core_framework_version() == "5.5.4"
 
 
+def test_run_compile_strict_reraises_pch_failure(
+    setup_core: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """ESPHOME_PCH_STRICT must reach through the real compile flow."""
+    from esphome.core import EsphomeError
+
+    monkeypatch.setenv("ESPHOME_PCH_ENABLE", "1")
+    monkeypatch.setenv("ESPHOME_PCH_STRICT", "1")
+    _setup_build(setup_core)
+
+    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=EsphomeError("ESPHOME_PCH_STRICT: no usable compile command"),
+        ),
+        pytest.raises(EsphomeError, match="no usable compile command"),
+    ):
+        toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False)
+
+
 def test_run_compile_invokes_prepare_pch_and_survives_failure(
     setup_core: Path, monkeypatch: pytest.MonkeyPatch
 ) -> None:

tests/unit_tests/test_platformio_pch_script.py

@@ -462,10 +462,34 @@ def test_pch_script_unreadable_local_header_skips_pch(
 
 def test_pch_script_strict_raises_when_pch_not_used(tmp_path: Path) -> None:
     """ESPHOME_PCH_STRICT fails the build instead of degrading."""
-    with pytest.raises(Exception, match="ESPHOME_PCH_STRICT|boom"):
+    with pytest.raises(RuntimeError, match="ESPHOME_PCH_STRICT"):
         _run_script(tmp_path, fail=True, env_vars={"ESPHOME_PCH_STRICT": "1"})
 
 
+def test_pch_script_strict_reraises_internal_errors(tmp_path: Path) -> None:
+    """The catch-all must not swallow programming errors in strict mode."""
+    with pytest.raises(TypeError):
+        _run_script(tmp_path, env_vars={"ESPHOME_PCH_STRICT": "1"}, platform_cls=None)
+
+
+def test_pch_script_strict_allows_nobuild_skip(tmp_path: Path) -> None:
+    """-t nobuild compiles nothing; the skip is expected even in strict."""
+    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"])
+    with patch.dict(os.environ, {"ESPHOME_PCH_STRICT": "1"}, clear=True):
+        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_strict_passes_on_success(tmp_path: Path) -> None:
     scons_env = _run_script(tmp_path, env_vars={"ESPHOME_PCH_STRICT": "1"})
     assert scons_env.prepended