Lex every build_flags entry with re-quoted emission and lock the shared cache install

tests/unit_tests/build_gen/test_arduino8266.py

@@ -607,3 +607,29 @@ def test_flag_defines_lexes_multi_token_entries() -> None:
     assert defines["FOO"] == "FOO=1"
     config = _resolve_build_config(defines)
     assert config.lwip_lib == "lwip2-1460"
+
+
+def test_project_flags_lexes_every_entry() -> None:
+    """A linker flag anywhere in an entry reaches the link line (PIO parity)."""
+    _set_flags("-DFOO=1 -lbar")
+    compile_flags, _link, _dirs, libs = arduino8266._project_flags()
+    assert libs == ["bar"]
+    assert "-DFOO=1" in compile_flags
+
+
+def test_project_flags_unflags_match_tokens() -> None:
+    """build_unflags removes a token embedded in a multi-token entry."""
+    _set_flags("-Os -g3")
+    CORE.build_unflags = {"-Os"}
+    compile_flags, _link, _dirs, _libs = arduino8266._project_flags()
+    assert "-g3" in compile_flags
+    assert "-Os" not in compile_flags
+
+
+def test_project_flags_requotes_lexed_defines() -> None:
+    """A quoted spaced value stays one compiler argument after lex/emit."""
+    _set_flags('-DGREETING="hello world"')
+    compile_flags, _link, _dirs, _libs = arduino8266._project_flags()
+    # shlex folds the quotes (as PIO's ParseFlags does); _shell_token
+    # re-quotes the spaced token so the shell passes one argv element
+    assert compile_flags == ['"-DGREETING=hello world"']

tests/unit_tests/test_arduino8266_framework.py

@@ -402,3 +402,30 @@ def test_install_package_unexpected_layout_raises(tmp_path: Path) -> None:
         mock_extract.side_effect = lambda *_a, **_kw: dest.mkdir()
         framework._install_package("pkg", "1.0.0", dest, ["http://m"], expect=("bin",))
     assert not (dest / ".esphome_extracted").exists()
+
+
+def test_install_package_marker_rechecked_under_lock(tmp_path: Path) -> None:
+    """A concurrent install finishing while we wait for the lock is detected."""
+    dest = tmp_path / "pkg"
+    marker = dest / ".esphome_extracted"
+
+    class _FakeLock:
+        def __init__(self, *_a, **_kw) -> None:
+            pass
+
+        def __enter__(self):
+            dest.mkdir(parents=True, exist_ok=True)
+            marker.touch()
+            return self
+
+        def __exit__(self, *args) -> None:
+            pass
+
+    with (
+        patch("filelock.FileLock", _FakeLock),
+        patch.object(framework, "download_from_mirrors") as mock_download,
+        patch.object(framework, "rmdir") as mock_rmdir,
+    ):
+        framework._install_package("pkg", "1.0.0", dest, ["http://m"])
+    mock_download.assert_not_called()
+    mock_rmdir.assert_not_called()