This information is missing from the event. Where we have end_commit (the merge commit usually), start_commit(oldest commit of the merged branch) and stop_commit(youngest commit of the merged branch).
The old_commit should be the sha before merge tip of the branch. Gerrit and Github provides this information. Zuul use it in some case and also to determine if a branch is created (old_commit: 00000000..0000).
Metadata Update from @pingou: - Issue tagged with: RFE
See https://pagure.io/pagure/pull-request/4626
https://pagure.io/pagure/pull-request/4626 has been merged.
Metadata Update from @fbo: - Issue close_status updated to: Fixed - Issue status updated to: Closed (was: Open)