[espidf] Skip ldgen when only app code changes (#18857)

tests/unit_tests/test_espidf_toolchain.py

@@ -630,6 +630,154 @@ def test_component_cache_ignores_corrupt_file(setup_core: Path, tmp_path: Path)
         assert toolchain.load_cached_builtin_components() is None
 
 
+@pytest.fixture(autouse=True)
+def _clear_ldgen_env(monkeypatch: pytest.MonkeyPatch) -> None:
+    """Isolate tests from ambient ldgen escape hatch and strict knobs."""
+    monkeypatch.delenv("ESPHOME_LDGEN_STRICT", raising=False)
+    monkeypatch.delenv("ESPHOME_LDGEN_FULL_DEPS", raising=False)
+
+
+def _write_fragments_build_ninja(tmp_path: Path, fragments: list[Path]) -> None:
+    build_dir = CORE.relative_build_path("build")
+    build_dir.mkdir(parents=True, exist_ok=True)
+    frag_list = ";".join(str(f) for f in fragments)
+    (build_dir / "build.ninja").write_text(
+        f'  COMMAND = python ldgen.py --fragments-list "{frag_list}" --input x\n'
+    )
+
+
+def test_warn_if_app_archive_mapped_warns(
+    setup_core: Path, tmp_path: Path, caplog: pytest.LogCaptureFixture
+) -> None:
+    """A fragment naming the app archive, even with trailing text or leading
+    whitespace, triggers the loud warning."""
+    _setup_build(setup_core)
+    frag = tmp_path / "linker.lf"
+    frag.write_text("[mapping:evil]\n archive: libsrc.a # app\nentries:\n")
+    _write_fragments_build_ninja(tmp_path, [frag])
+    toolchain._warn_if_app_archive_mapped()
+    assert "maps the app archive" in caplog.text
+
+
+def test_warn_if_app_archive_mapped_scans_past_unreadable(
+    setup_core: Path, tmp_path: Path, caplog: pytest.LogCaptureFixture
+) -> None:
+    """An unreadable fragment doesn't stop later fragments being checked."""
+    _setup_build(setup_core)
+    frag = tmp_path / "linker.lf"
+    frag.write_text("[mapping:evil]\narchive: libsrc.a\n")
+    _write_fragments_build_ninja(tmp_path, [tmp_path / "missing.lf", frag])
+    toolchain._warn_if_app_archive_mapped()
+    assert "maps the app archive" in caplog.text
+
+
+def test_warn_if_app_archive_mapped_strict_no_fragments_list(
+    setup_core: Path, tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Under strict, a build.ninja the check can't parse fails the build."""
+    monkeypatch.setenv("ESPHOME_LDGEN_STRICT", "1")
+    _setup_build(setup_core)
+    build_dir = CORE.relative_build_path("build")
+    build_dir.mkdir(parents=True, exist_ok=True)
+    (build_dir / "build.ninja").write_text("rule CXX\n  command = gcc\n")
+    with pytest.raises(EsphomeError, match="no --fragments-list"):
+        toolchain._warn_if_app_archive_mapped()
+
+
+def test_warn_if_app_archive_mapped_strict_raises(
+    setup_core: Path, tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Under ESPHOME_LDGEN_STRICT a mapped app archive fails the build."""
+    monkeypatch.setenv("ESPHOME_LDGEN_STRICT", "1")
+    _setup_build(setup_core)
+    frag = tmp_path / "linker.lf"
+    frag.write_text("[mapping:evil]\narchive: libsrc.a\n")
+    _write_fragments_build_ninja(tmp_path, [frag])
+    with pytest.raises(EsphomeError, match="maps the app archive"):
+        toolchain._warn_if_app_archive_mapped()
+
+
+def test_warn_if_app_archive_mapped_glob(
+    setup_core: Path, tmp_path: Path, caplog: pytest.LogCaptureFixture
+) -> None:
+    """A glob archive spec that selects the app archive is also flagged."""
+    _setup_build(setup_core)
+    frag = tmp_path / "linker.lf"
+    frag.write_text("[mapping:evil]\narchive: lib*\n")
+    _write_fragments_build_ninja(tmp_path, [frag])
+    toolchain._warn_if_app_archive_mapped()
+    assert "maps the app archive" in caplog.text
+
+
+def test_warn_if_app_archive_mapped_clean(
+    setup_core: Path, tmp_path: Path, caplog: pytest.LogCaptureFixture
+) -> None:
+    """Normal fragments, including IDF's stock archive: * catch-all,
+    produce no warning."""
+    _setup_build(setup_core)
+    frag = tmp_path / "linker.lf"
+    frag.write_text(
+        "[mapping:freertos]\narchive: libfreertos.a\n[mapping:default]\narchive: *\n"
+    )
+    _write_fragments_build_ninja(tmp_path, [frag])
+    toolchain._warn_if_app_archive_mapped()
+    assert "maps the app archive" not in caplog.text
+
+
+def test_warn_if_app_archive_mapped_missing_fragment(
+    setup_core: Path, tmp_path: Path, caplog: pytest.LogCaptureFixture
+) -> None:
+    """An unreadable fragment file is non-fatal."""
+    _setup_build(setup_core)
+    _write_fragments_build_ninja(tmp_path, [tmp_path / "missing.lf"])
+    toolchain._warn_if_app_archive_mapped()
+    assert "maps the app archive" not in caplog.text
+
+
+def test_warn_if_app_archive_mapped_no_build_ninja(setup_core: Path) -> None:
+    """No build.ninja yet is a quiet no-op."""
+    _setup_build(setup_core)
+    toolchain._warn_if_app_archive_mapped()
+
+
+def test_warn_if_app_archive_mapped_no_fragments_list(setup_core: Path) -> None:
+    """A build.ninja without a fragments-list argument is a quiet no-op."""
+    _setup_build(setup_core)
+    build_dir = CORE.relative_build_path("build")
+    build_dir.mkdir(parents=True, exist_ok=True)
+    (build_dir / "build.ninja").write_text("rule CXX\n  command = gcc\n")
+    toolchain._warn_if_app_archive_mapped()
+
+
+def test_run_compile_runs_fragment_check(setup_core: Path) -> None:
+    """The fragment belt runs by default on every compile."""
+    _setup_build(setup_core)
+
+    with (
+        _up_to_date_compile(),
+        patch.object(toolchain, "_warn_if_app_archive_mapped") as mock_check,
+    ):
+        assert toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False) == 0
+
+    mock_check.assert_called_once()
+
+
+def test_run_compile_full_deps_skips_fragment_check(
+    setup_core: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """ESPHOME_LDGEN_FULL_DEPS disables the fragment belt with the override."""
+    monkeypatch.setenv("ESPHOME_LDGEN_FULL_DEPS", "1")
+    _setup_build(setup_core)
+
+    with (
+        _up_to_date_compile(),
+        patch.object(toolchain, "_warn_if_app_archive_mapped") as mock_check,
+    ):
+        assert toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False) == 0
+
+    mock_check.assert_not_called()
+
+
 @pytest.mark.parametrize("limit", [1, None])
 def test_run_compile_passes_compile_process_limit(
     setup_core: Path, limit: int | None