mpl(bigtable): error when read_buffer is not empty and stream finishes

[scotthart]

We were checking for buffered_rows_ not empty but we also needed to check for read_buffer_ not empty which indicates the stream finished with uncommited rows or unprocessed data.

[gemini-code-assist]

Summary of Changes

Hello @scotthart, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a critical bug in the Bigtable client library where ExecuteQuery streams could terminate with unprocessed data without proper error reporting. It introduces a more comprehensive check for uncommitted data at the end of a stream. Concurrently, the PR refactors the query plan refresh retry mechanism, centralizing and enhancing the logic for detecting expired query plans by parsing gRPC status payloads. These changes improve the robustness of stream processing and error handling within the Bigtable client.

Highlights

• Bug Fix: Uncommitted Rows Error: Corrected an issue where the ExecuteQuery stream could finish with uncommitted rows or unprocessed data in the read_buffer_ without reporting an error. The fix now explicitly checks read_buffer_ in addition to buffered_rows_ to catch this condition.
• Refactor: Query Plan Refresh Retry Logic: The SafeGrpcRetryAllowingQueryPlanRefresh struct has been renamed to QueryPlanRefreshRetry and its IsQueryPlanExpired logic has been moved to a new .cc file (internal/retry_traits.cc). This change allows for more robust parsing of gRPC status payloads to determine if a query plan has expired, improving retry behavior.
• Improved Error Reporting: Error reporting in data_connection_impl.cc and partial_result_set_source.cc has been enhanced by utilizing internal::AbortedError and internal::InternalError with GCP_ERROR_INFO(), providing more detailed context for debugging.
• Build System Updates: The CMakeLists.txt and google_cloud_cpp_bigtable.bzl files have been updated to include the newly introduced internal/retry_traits.cc source file.
• Conformance Test Adjustments: The run_conformance_tests_proxy_bazel.sh script has been modified to include new TestExecuteQuery cases related to plan refresh and to adjust the list of skipped tests.

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[gemini-code-assist]

Code Review

This pull request correctly fixes a bug where data in read_buffer_ could be lost if a stream finished before the buffer was processed. The check is now correctly performed against both buffered_rows_ and read_buffer_.

Additionally, the PR includes a nice refactoring of the query plan refresh retry logic. The new QueryPlanRefreshRetry trait improves robustness by inspecting the structured error details in the Status payload, not just the error message. The new tests for this logic are comprehensive and well-written.

I have a couple of minor points for consideration regarding a typo in a copyright header and a clarification on a change in retry behavior for kInternal errors.

[codecov]

Codecov Report

❌ Patch coverage is 60.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 92.95%. Comparing base (2366ddf) to head (1e2a567).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...oud/bigtable/internal/partial_result_set_source.cc	33.33%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #15775      +/-   ##
==========================================
+ Coverage   92.94%   92.95%   +0.01%     
==========================================
  Files        2449     2449              
  Lines      226518   226520       +2     
==========================================
+ Hits       210531   210563      +32     
+ Misses      15987    15957      -30     

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