MLE-26428 More sensible null handling for incremental write

[rjrudin]

No description provided.

[Copilot]

Pull request overview

This PR improves null and empty string handling for incremental write metadata key names by ignoring invalid values and using defaults instead. This prevents users from inadvertently breaking the incremental write feature by passing null or empty key names, which could occur through integrations like the Spark connector.

Key Changes:

• Added validation to ignore null or empty strings for hash and timestamp key names
• Enhanced test coverage with two new test cases validating custom key names and null handling behavior

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
IncrementalWriteFilter.java	Added null/empty string validation in hashKeyName() and timestampKeyName() builder methods to prevent invalid key names
IncrementalWriteTest.java	Added customTimestampKeyName() test to verify custom key names work correctly, and nullIsIgnoredForKeyNames() test to verify null values fall back to defaults

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[github-actions]

Copyright Validation Results
Total: 2 | Passed: 2 | Failed: 0 | Skipped: 0 | at: 2026-01-02 16:55:25 UTC | commit: f10a54d

✅ Valid Files

• marklogic-client-api/src/main/java/com/marklogic/client/datamovement/filter/IncrementalWriteFilter.java
• marklogic-client-api/src/test/java/com/marklogic/client/datamovement/filter/IncrementalWriteTest.java

✅ All files have valid copyright headers!