When the source branch of a pull request is force-pushed and becomes identical to the destination branch, the PR can be automatically merged because there are no remaining changes or differences to merge. This is expected from a mergeability perspective.

However, marking the PR as Merged can be misleading because no actual code changes were merged through the PR.

Instead, in this scenario, the PR could be automatically declined with a clear reason displayed in the PR banner, explaining that the source and destination branches are now identical and there are no changes remaining to merge or keep the PR open stating no changes in source and destination branch.

This would provide more accurate PR lifecycle and reporting statistics, as marking such PRs as merged can result in incorrect metrics for successfully merged pull requests.