Strict re-probes a cached .gch, probe diagnostics get the exit-code fallback, nobuild detection narrows to ImportError

tests/unit_tests/build_gen/test_espidf.py

@@ -1257,3 +1257,42 @@ def test_prepare_pch_probe_rejection_latches_and_degrades(
         pytest.raises(EsphomeError, match="cannot load the pch"),
     ):
         prepare_pch()
+
+
+def test_prepare_pch_strict_reprobes_cached_gch(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Rejection is per-process: strict must re-prove a cached .gch loads."""
+    from esphome.build_gen.espidf import prepare_pch
+    from esphome.core import EsphomeError
+
+    dev = _make_pch_device(tmp_path, "dev_rc")
+    CORE.build_path = dev
+    gch = dev / "build" / "esphome_pch.h.gch"
+
+    def ok(cmd, **kwargs):
+        if "-fsyntax-only" not in cmd:
+            gch.write_bytes(b"gch")
+        return subprocess.CompletedProcess(cmd, 0, "", "")
+
+    with (
+        patch.object(CORE, "name", "test"),
+        patch("esphome.build_helpers.pch.subprocess.run", side_effect=ok),
+    ):
+        prepare_pch()
+    assert gch.exists()
+
+    def reject(cmd, **kwargs):
+        assert "-fsyntax-only" in cmd, "cached path must not recompile"
+        return subprocess.CompletedProcess(
+            cmd, 0, "", "warning: esphome_pch.h.gch: had text segment "
+        )
+
+    monkeypatch.setenv("ESPHOME_PCH_STRICT", "1")
+    with (
+        patch.object(CORE, "name", "test"),
+        patch("esphome.build_helpers.pch.subprocess.run", side_effect=reject),
+        pytest.raises(EsphomeError, match="cannot load the pch"),
+    ):
+        prepare_pch()
+    assert not gch.exists()

tests/unit_tests/test_platformio_pch_script.py

@@ -472,8 +472,15 @@ def test_pch_script_strict_reraises_internal_errors(tmp_path: Path) -> None:
         _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."""
+@pytest.mark.parametrize(("targets", "passes"), [(["nobuild"], True), ([], False)])
+def test_pch_script_strict_projenv_skip_gated_on_nobuild(
+    tmp_path: Path, targets: list[str], passes: bool
+) -> None:
+    """-t nobuild compiles nothing, so the skip passes strict; a missing
+    projenv on a real compile must not."""
+    import sys
+    import types
+
     proj = tmp_path / "dev"
     (proj / "src").mkdir(parents=True)
 
@@ -481,12 +488,23 @@ def test_pch_script_strict_allows_nobuild_skip(tmp_path: Path) -> None:
         if "projenv" in names:
             raise RuntimeError("Import of non-existent variable 'projenv'")
 
+    scons = types.ModuleType("SCons")
+    scons_script = types.ModuleType("SCons.Script")
+    scons_script.COMMAND_LINE_TARGETS = targets
     env = _FakeSConsEnv(proj, proj / "src", "g++", ["-DX=1"])
-    with patch.dict(os.environ, {"ESPHOME_PCH_STRICT": "1"}, clear=True):
-        exec(  # noqa: S102
+    with (
+        patch.dict(sys.modules, {"SCons": scons, "SCons.Script": scons_script}),
+        patch.dict(os.environ, {"ESPHOME_PCH_STRICT": "1"}, clear=True),
+    ):
+        run = lambda: exec(  # noqa: S102, E731
             compile(_SCRIPT.read_text(), "pch.py", "exec"),
             {"Import": strict_import, "env": env},
         )
+        if passes:
+            run()
+        else:
+            with pytest.raises(RuntimeError, match="not used"):
+                run()
     assert not (proj / "esphome_pch.h").exists()