abinash2553J opened a new pull request, #11288: URL: https://github.com/apache/arrow-rs/pull/11288
# Which issue does this PR close? <!-- We generally require a GitHub issue to be filed for all bug fixes and enhancements and this helps us generate change logs for our releases. You can link an issue to this PR using the GitHub syntax. --> - Closes #11284. # Rationale for this change Union arrays do not have their own validity bitmap. When a null value is introduced into a union, the null must therefore be represented by one of its child arrays. The current implementation assumes the first union child can represent nulls. This is incorrect when the first child is non-nullable and another child is nullable. <!-- Why are you proposing this change? If this is already explained clearly in the issue then this section is not needed. Explaining clearly why changes are proposed helps reviewers understand your changes and offer better suggestions for fixes. --> # What changes are included in this PR? Select a nullable union child when constructing null ArrayData. Select a nullable child when extending nulls in dense unions. Use the nullable child type ID when extending nulls in sparse unions. Fail clearly when a union has no nullable child available to represent nulls. Add regression coverage for unions where the first child is non-nullable and a later child is nullable. <!-- There is no need to duplicate the description in the issue here but it is sometimes worth providing a summary of the individual changes in this PR. --> # Are these changes tested? Yes Existing union tests were updated to cover the case where the first child is non-nullable and a later child is nullable. The tests verify that null values use the nullable child's type ID. <!-- We typically require tests for all PRs in order to: 1. Prevent the code from being accidentally broken by subsequent changes 2. Serve as another way to document the expected behavior of the code If tests are not included in your PR, please explain why (for example, are they covered by existing tests)? If this PR claims a performance improvement, please include evidence such as benchmark results. --> # Are there any user-facing changes? This is a bug fix with no public API changes. It corrects null representation for union arrays whose first child is non-nullable, preventing invalid nullability from being introduced during null construction or transformation. <!-- If there are user-facing changes then we may require documentation to be updated before approving the PR. If there are any breaking changes to public APIs, please call them out. --> -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
