[time] Handle Windows EINVAL when validating POSIX TZ strings (#15934)

esphome/components/time/__init__.py

@@ -1,3 +1,4 @@
+import errno
 from importlib import resources
 import logging
 
@@ -74,6 +75,12 @@ def _load_tzdata(iana_key: str) -> bytes | None:
         return (resources.files(package) / resource).read_bytes()
     except (FileNotFoundError, ModuleNotFoundError, IsADirectoryError):
         return None
+    except OSError as e:
+        # Windows raises EINVAL for paths with NTFS-illegal chars (e.g. '<'/'>'
+        # in POSIX TZ strings like "<+08>-8" that validate_tz feeds back here).
+        if e.errno == errno.EINVAL:
+            return None
+        raise
 
 
 def _extract_tz_string(tzfile: bytes) -> str:

tests/unit_tests/components/test_time.py

@@ -1,6 +1,11 @@
 """Tests for time component cron expression parsing."""
 
-from esphome.components.time import _parse_cron_part
+import errno
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from esphome.components.time import _load_tzdata, _parse_cron_part, validate_tz
 
 
 def test_star_slash_seconds() -> None:
@@ -78,3 +83,63 @@ def test_range() -> None:
 
 def test_single_value() -> None:
     assert _parse_cron_part("30", 0, 59, {}) == {30}
+
+
+def _mock_resources_with_error(error: Exception) -> MagicMock:
+    """Return a mock of importlib.resources.files where read_bytes raises error."""
+    leaf = MagicMock()
+    leaf.read_bytes.side_effect = error
+    package = MagicMock()
+    package.__truediv__.return_value = leaf
+    return MagicMock(return_value=package)
+
+
+def test_load_tzdata_returns_none_on_windows_einval() -> None:
+    """On Windows, opening a tzdata path with NTFS-illegal chars raises OSError(EINVAL).
+
+    Regression test for crash when the system TZ resolves to a POSIX string like
+    "<+08>-8" (Asia/Shanghai, IST, etc.) and is fed back into _load_tzdata by
+    validate_tz to check whether it is also a valid IANA key.
+    """
+    err = OSError(errno.EINVAL, "Invalid argument")
+    with patch(
+        "esphome.components.time.resources.files",
+        _mock_resources_with_error(err),
+    ):
+        assert _load_tzdata("<+08>-8") is None
+
+
+def test_load_tzdata_propagates_unexpected_oserror() -> None:
+    """Unrelated OSErrors (e.g. PermissionError) must not be swallowed."""
+    with (
+        patch(
+            "esphome.components.time.resources.files",
+            _mock_resources_with_error(
+                PermissionError(errno.EACCES, "Permission denied")
+            ),
+        ),
+        pytest.raises(PermissionError),
+    ):
+        _load_tzdata("Some/Zone")
+
+
+def test_load_tzdata_returns_none_on_file_not_found() -> None:
+    """Existing behavior: missing tz file returns None rather than raising."""
+    with patch(
+        "esphome.components.time.resources.files",
+        _mock_resources_with_error(FileNotFoundError()),
+    ):
+        assert _load_tzdata("Not/A/Zone") is None
+
+
+def test_validate_tz_accepts_posix_string_when_read_bytes_raises_einval() -> None:
+    """validate_tz must not crash when _load_tzdata hits the Windows EINVAL path.
+
+    Simulates the Windows case where the auto-detected POSIX TZ string is fed
+    back through _load_tzdata and the underlying read_bytes raises errno 22.
+    """
+    with patch(
+        "esphome.components.time.resources.files",
+        _mock_resources_with_error(OSError(errno.EINVAL, "Invalid argument")),
+    ):
+        assert validate_tz("<+08>-8") == "<+08>-8"