[yashgupta29032006]

Summary

Make google.api_core.exceptions.RetryError support pickling and copying.

Changes

• Implement RetryError.__reduce__() to reconstruct the exception with both its message and cause.
• Add regression tests for pickle, shallow copy, and deep copy, including a None cause.

Testing

• pytest tests/unit/test_exceptions.py -q
• pytest tests/unit -W "ignore::pytest.PytestDeprecationWarning" -q
• pytest tests/asyncio -W "ignore::pytest.PytestDeprecationWarning" -q

Fixes #18946

[gemini-code-assist]

Code Review

This pull request implements a __reduce__ method in google/api_core/exceptions.py to support pickling and copying of exception objects, adds corresponding unit tests, and updates docstrings in the Firestore client. The review feedback correctly points out that the current __reduce__ implementation only returns a 2-tuple, which would discard other instance attributes stored in __dict__. It is recommended to return a 3-tuple containing self.__dict__ to preserve all state, and to update the unit tests to verify that custom attributes are retained and that shallow copying preserves object identity for the exception's cause.

[yashgupta29032006]

Hi maintainers, I’ve opened this PR to address issue #18946 by making RetryError support pickling and copying, with regression tests included. The required multi-approvers check is currently failing because it requires internal approvals. Could someone please review the changes when convenient? Thank you!

[parthea]

Closing as #18947 also addresses the same issue