I don't really ever find myself having to do that. I guess it's been a long time since I worked in an environment which did not use an "only merge to main after passing CI" workflow, and back then we weren't using git, anyway.
There was one git-using startup I worked for which had a merge-recklessly development style, and there was one occasion when I could have used `git bisect` to disprove my coworker's accusation that I had thoughtlessly broken the build (it was him, actually, and, yuck - what a toxic work environment!), but the commit in question was like HEAD~3 so it would probably have taken me longer to use git bisect than to just test it by hand.
> I don't really ever find myself having to do that. I guess it's been a long time since I worked in an environment which did not use an "only merge to main after passing CI" workflow, and back then we weren't using git, anyway.
You _never_ have bugs that slip through the test suite? That is extremely impressive / borderline impossible. Even highly tested gold-standard projects like SQLite see bugs in production.
And once you find a regression that wasn't covered by your test suite, the fastest way to find where it originated is often git bisect.
Bugs that slip through the test suite and it's important to trace the origin and it requires building more than a couple best-guess versions to find it. And even then, if it wastes an hour or two once in a blue moon that's not a big motivator for workflow changes.
You're skeptical of a far stronger claim than the one they actually made.
> I guess it's been a long time since I worked in an environment which did not use an "only merge to main after passing CI"
It's the same for me, but some integration bugs still escape the notice of unit tests. Examples from memory: a specific subset users being thrown into an endless redirect due to a cookie rename that wasn't propagated across all sub-systems on the backend, multiple instances of run-time errors that resulted from dependency version mismatches (dynamic loading), and a new notification banner element covering critical UI elements on an infrequently used page - effectively conflicting CSS position. In all these cases, the CI tests were passing, but passing tests don't mean your software is working as expected in all cases.
I also find git bisect to be useful, but very rarely and never for personal projets.
In the cases you mentioned, robust e2e and integration tests would ideally be able to catch the bugs. And for the UI issue in particular, I wouldn't think to track down the commit that caused it, but just fix it and move on.
There was one git-using startup I worked for which had a merge-recklessly development style, and there was one occasion when I could have used `git bisect` to disprove my coworker's accusation that I had thoughtlessly broken the build (it was him, actually, and, yuck - what a toxic work environment!), but the commit in question was like HEAD~3 so it would probably have taken me longer to use git bisect than to just test it by hand.