Avoid dismissing approvals on restacks alone

[lunelson]

Summary

• Avoid dismissing approvals solely because restacking/rebasing rewrote commit IDs
• Defer rewritten-history cases to the existing range-diff stale-check logic
• Add self-test coverage for safe restacks and changed patch series

Tests

• npm ci
• npx renovate-config-validator
• .github/actions/dismiss-stale-approvals/self-test.sh

[cursor]

PR Summary

Medium Risk
Changes the stale-approval decision logic in the GitHub Action, which can affect whether PR approvals are dismissed; mistakes could leave stale approvals in place or dismiss valid ones. Scope is small and covered by expanded self-tests.

Overview
Stops treating “approval commit is not an ancestor of HEAD” as automatically stale in check-manual-merge-resolutions.sh, so simple rebases/restacks no longer dismiss approvals and the decision is deferred to the existing git range-diff check.

Updates self-test.sh to reflect the new behavior and adds coverage to ensure rewritten history only becomes stale when range-diff detects a changed patch series (and that the final decision output points reviewers to the range-diff output).

^{Reviewed by Cursor Bugbot for commit befef1c. Bugbot is set up for automated code reviews on this repo. Configure here.}

[augmentcode]

🤖 Augment PR Summary

Summary: This PR adjusts the “dismiss stale approvals” action to avoid dismissing approvals just because a rebase/restack rewrote commit SHAs.

Changes:

• Updates the manual merge-resolution check to no longer mark approvals stale solely when the approval commit is no longer an ancestor of the PR head.
• Relies on the existing git range-diff-based stale check to detect whether the reviewed patch series actually changed after history rewrites.
• Extends the self-test suite to cover “rewritten history defers to range-diff” and “rewritten + changed patch series becomes stale via range-diff”.

Technical Notes: The ancestry check now acts as a gate: non-ancestor cases return non-stale and let the range-diff step determine staleness.

_{🤖 Was this summary useful? React with 👍 or 👎}

[augmentcode]

Review completed. No suggestions at this time.

Comment augment review to trigger a new review at any time.