Test Merge Commit Generation Changes

GitHub has optimized the frequency of test merge commit generation for pull requests to reduce delays and improve system reliability. This backend change focuses on when these commits are created, not how mergeability is determined.

When Test Merge Commits Are Generated

Test merge commits are now only generated under these conditions:

• Code changes: When new commits are pushed to the pull request branch
• Merge base changes: When the merge base between the PR and base branches changes
• Time-based refresh: When the current test merge commit is older than 12 hours

Previously, test merge commits were regenerated every time a pull request page was viewed, causing unnecessary system load.

What Remains Unchanged

This optimization does not affect:

• Mergeability checks: PR mergeability status determination remains unaffected
• Merge conflict detection: Conflicts are still properly reported
• Rule enforcement: Branch protection and merge rules continue to work as expected

Impact for Developers

This change improves the overall responsiveness of GitHub's pull request system by reducing computational overhead. Developers will experience faster page load times and more reliable mergeability status updates, with no impact on the accuracy or completeness of merge conflict detection and rule enforcement.