WriteToJson - force num_shards

[derrickaw]

1. Flaky csv_to_json test due to num_shards parameter not being honored.
2. Try to force the honoring if parameter is present.

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[derrickaw]

/gemini review

[gemini-code-assist]

Code Review

This pull request updates the WriteToFiles implementation in the Beam DataFrame IO to set max_writers_per_bundle to 0 when num_shards is specified. The reviewer identified a bug where max_writers_per_bundle is not removed from the keyword arguments, which could lead to a TypeError in the underlying pandas writer. The feedback also suggests allowing users to override the default max_writers_per_bundle value for better flexibility and provides a code snippet to address these issues.

[gemini-code-assist]

Summary of Changes

Hello, 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 improves the reliability of file writing operations in the Apache Beam Python SDK. By modifying how num_shards and max_writers_per_bundle are passed to WriteToFiles, it ensures that user-specified shard configurations are properly honored, resolving intermittent test failures.

Highlights

• Fixing Flaky Tests: Addressed an issue where the csv_to_json test was flaky due to the num_shards parameter not being correctly applied.
• Parameter Enforcement: Updated the WriteToJson logic to explicitly force the num_shards parameter when provided, ensuring consistent behavior in file writing operations.

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[gemini-code-assist]

Code Review

This pull request updates the expand method in sdks/python/apache_beam/dataframe/io.py to extract and pass num_shards and max_writers_per_bundle to the WriteToFiles transform. Feedback suggests using a local copy of self.kwargs instead of mutating the instance attribute directly to ensure the transform remains idempotent and safe for reuse. A code suggestion was also provided to simplify the logic and correctly handle the default value for max_writers_per_bundle when sharding is specified.