My preferred variant of this would be - write new tests to expose it, but not commit the tests - bisect commits, running new tests each time - find culprit c

My preferred variant of this would be - write new tests to expose it, but not commit the tests - bisect commits, running new tests each time - find culprit commit - stop bisecting, fix bug - Look for similar bugs nearby, and ways to improve the new tests, now I know the root problem. - Figure out the best series of commits for the tests and fixes together, that will be easiest to review by my colleagues/future me/alien archaeologists. - Send PRs/commit to main.