Hymenaeus
Hymenaeus is a greek god of marriage ceremonies, similar to PRs in our VCS being the request to marry a commit with another branch. This Greek god helps us with automatically reapproving PRs which were already approved.
Once a PR is rebased, the base branch changes or commits get squashed, the PR would usually require a review. If the PR already received an approving review for the same code change, then Hymenaeus issues the approval again. Nobody has to review the same code twice. However, if the approved code change is not the current change, an actual approving review is still required.
Why GitHub's own stacked pull requests do not replace it
GitHub's stacked pull requests reached public preview in July 2026, which raised the obvious question. They do not solve this. A restack rewrites the head SHA, and a branch with "dismiss stale approvals" drops the approval even when the diff against the base is byte-identical. Preserving them is an open feature request, not shipped behaviour.
So Hymenaeus stays. Delete it when GitHub preserves approvals across a restack. The only other option is turning off stale-approval dismissal entirely, which gives up the protection for real changes too.
Possible improvement, unowned
On Cloud Run as a webhook, re-approval would be instant instead of waiting on a workflow run,
and off GitHub Actions minutes. Unowned and low priority. It works well enough. See
/.github.