DeprecationWarning on Python 3.12+: bundled well_known_types.py uses deprecated datetime.datetime.utcfromtimestamp

Description

lark_oapi bundles a vendored copy of protobuf's well_known_types.py under lark_oapi/ws/pb/google/protobuf/internal/. That vendored file still calls datetime.datetime.utcfromtimestamp(0), which is deprecated in Python 3.12+ and emits a DeprecationWarning on Python 3.13/3.14:

.../lark_oapi/ws/pb/google/protobuf/internal/well_known_types.py:91: DeprecationWarning:
  datetime.datetime.utcfromtimestamp() is deprecated and scheduled for removal in a future version.
  Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.fromtimestamp(timestamp, datetime.UTC).
  _EPOCH_DATETIME_NAIVE = datetime.datetime.utcfromtimestamp(0)

Upstream google.protobuf already replaced this call (it now uses datetime.fromtimestamp(0, datetime.timezone.utc)), but the copy pinned inside lark_oapi has not been regenerated, so users on Python 3.12+ still hit the warning whenever the WebSocket (lark_oapi.ws) protobuf code is imported.

Reproduction

Environment:

• Python: 3.14.6
• lark-oapi: 1.7.1 (installed from PyPI; also reproducible against v2_main at the path below)
• OS: macOS

Steps:

python -W error::DeprecationWarning -c "import lark_oapi.ws.pb.google.protobuf.internal.well_known_types"

Expected: import succeeds with no warning.

Actual:

.../lark_oapi/ws/pb/google/protobuf/internal/well_known_types.py:91: DeprecationWarning:
  datetime.datetime.utcfromtimestamp() is deprecated and scheduled for removal in a future version.
  Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.fromtimestamp(timestamp, datetime.UTC).

Location

lark_oapi/ws/pb/google/protobuf/internal/well_known_types.py:91 (still present on v2_main):

_EPOCH_DATETIME_NAIVE = datetime.datetime.utcfromtimestamp(0)
_EPOCH_DATETIME_AWARE = datetime.datetime.fromtimestamp(
    0, tz=datetime.timezone.utc)

The _AWARE variant right below already uses the timezone-aware form; only the _NAIVE line needs to change.

Suggested fix

utcfromtimestamp cannot be made timezone-aware directly; replace it with the equivalent naive UTC datetime constructed from the already-correct aware value, e.g.:

_EPOCH_DATETIME_NAIVE = datetime.datetime.fromtimestamp(
    0, tz=datetime.timezone.utc).replace(tzinfo=None)

This preserves the original "naive UTC" semantics that callers of _EPOCH_DATETIME_NAIVE rely on (used at line 251: return _EPOCH_DATETIME_NAIVE + delta) while removing the deprecated API call.

Alternatively, regenerate the vendored protobuf stubs from a current googleapis/python-protobuf release so the whole bundled copy tracks upstream fixes.

Impact

• Functional impact: none (warning only; behavior is unchanged).
• DX impact: noisy logs, fails test runs that elevate DeprecationWarning to errors, and will turn into a hard AttributeError once Python removes the API (currently scheduled for a future 3.x release).

Workaround

Users can suppress the warning locally, e.g.:

import warnings
warnings.filterwarnings(
    "ignore",
    message="datetime.datetime.utcfromtimestamp.*",
    category=DeprecationWarning,
)

—but the bundled protobuf code should be updated at the source.

Start at lark_oapi/ws/pb/google/protobuf/internal/well_known_types.py:91 and compare the naive epoch value with the timezone-aware value immediately below it. Preserve the naive UTC semantics while removing the deprecated call. Run python -W error::DeprecationWarning -c "import lark_oapi.ws.pb.google.protobuf.internal.well_known_types"; done means the import succeeds without a warning.