monocle branches that fail when merged to master, one thing that’s sometimes done is using something called a “merge queue”. My understanding is that instead of merging straight to master, you add your PR to the merge queue. It runs through CI again with all commits from master and if it passes, it’s merged and deployed as usual. If it fails, it’s removed from the merge queue and the problems can be resolved in the PR.
So it’s kind of like a speculative merge to master that gets auto-reverted if it fails, with no permanent record of the failed merge. It should address situations like Stephen’s, where a linting rule was added before his PR was merged. It would not necessarily address flaky tests if those tests got lucky and passed both the branch CI and the merge queue CI.

https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/configuring-pull-request-merges/using-a-merge-queue

https://shopify.engineering/introducing-the-merge-queue