Fix NPE that occurs with DELETE w/o clustering key

[komamitsu]

Description

I noticed committing records silently fail when deleting a record without clustering key. It doesn't cause integration test failures since committing state itself finishes successfully and the failure of commit-record is ignored. This PR fixed the issue.

Related issues and/or PRs

https://github.com/scalar-labs/scalardb/pull/2957/files#diff-a77001aa78b9f7b380bda3d90371dd74610f8a344d04a5aa42c2ae8b704d901eR121, I guess.

Changes made

Avoid setting clusteringKey() to null in CommitMutationComposer#composeDelete().

Checklist

The following is a best-effort checklist. If any items in this checklist are not applicable to this PR or are dependent on other, unmerged PRs, please still mark the checkboxes after you have read and understood each item.

• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation to reflect the changes.
• I have considered whether similar issues could occur in other products, components, or modules if this PR is for bug fixes.
• Any remaining open issues linked to this PR are documented and up-to-date (Jira, GitHub, etc.).
• Tests (unit, integration, etc.) have been added for the changes.
• My changes generate no new warnings.
• Any dependent changes in other PRs have been merged and published.

Additional notes (optional)

None

Release notes

N/A

[gemini-code-assist]

Summary of Changes

Hello @komamitsu, 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 NullPointerException (NPE) that occurred when attempting to delete records without a clustering key. Previously, committing such delete operations would silently fail because the clusteringKey() method was explicitly set to null, leading to an issue during the commit process. The fix ensures that the clustering key is only set if it is present, preventing the NPE and allowing these delete operations to complete successfully.

Highlights

• NPE Fix for DELETE operations: Resolved a NullPointerException that occurred when performing DELETE operations without a clustering key by modifying the composeDelete method in CommitMutationComposer to conditionally set the clustering key.
• Improved Clustering Key Handling: The composeDelete method now uses Optional.ifPresent to apply the clustering key only when it exists, avoiding the explicit passing of null.
• Enhanced Test Coverage: Added new test cases in CommitMutationComposerTest to specifically validate the correct behavior of Put and Delete operations when no clustering key is provided.

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[gemini-code-assist]

Code Review

This pull request correctly fixes a NullPointerException that could occur during a DELETE operation on a record without a clustering key. The modification in CommitMutationComposer to use ifPresent for conditionally setting the clustering key is a clean and appropriate solution. The new tests added in CommitMutationComposerTest are well-written and provide good coverage for the fix, especially the case for deletes without a clustering key. I've included one suggestion to improve the maintainability of the test code by refactoring duplicated logic.

[Torch3333]

LGTM, thank you!

[Copilot]

Pull Request Overview

This PR fixes a NullPointerException that occurs when deleting records without clustering keys in the consensus commit transaction system. The issue was causing silent failures during commit operations where null clustering keys were being passed to builder methods that don't accept null values.

Key changes made:

• Modified CommitMutationComposer and RollbackMutationComposer to conditionally set clustering keys only when present
• Updated both composers to use builder patterns that avoid passing null values
• Added comprehensive test coverage for operations without clustering keys

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
CommitMutationComposer.java	Fixed NPE by conditionally setting clustering key in delete operations using Optional.ifPresent()
RollbackMutationComposer.java	Applied same fix to rollback operations and updated get operation to handle null clustering keys
CommitMutationComposerTest.java	Added test cases for put and delete operations without clustering keys
RollbackMutationComposerTest.java	Added test case for put operations without clustering keys in rollback scenarios

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[brfrn169]

LGTM! Thank you for handling this!

[feeblefakie]

LGTM! Thank you!