The Effectiveness of Git Bisect

equivalent), but works when your bug is intermittent. That is, it works in the presence of false negatives (when a version happens to work this time even though it contains the bug). It assumes that there are no false positives (in principle, the same approach would work, but adding it may be non-trivial). _____________ But BBChop is independent of any VCS and it would be easier for Git users to have something integrated in Git. Conclusion ---------- We have seen that regressions are an important problem, and that "git bisect" has nice features that complement very well practices and other tools, especially test suites, that are generally used to fight regressions. But it might be needed to change some work-flows and (bad) habits to get the most out of it. Some improvements to the algorithms inside "git bisect" are possible and some new features could help in some cases, but overall "git bisect" works already very well, is used a lot, and is already very useful. To back up that last claim, let's give the final word to Ingo Molnar when he was asked by the author how much time does he think "git bisect" saves him when he uses it: _____________ a _lot_. About ten years ago did i do my first 'bisection' of a Linux patch queue. That was prior the Git (and even prior the BitKeeper) days. I literally days spent sorting out patches, creating what in essence were standalone commits that i guessed to be related to that bug. It was a tool of absolute last resort. I'd rather spend days looking at printk output than do a manual 'patch bisection'. With Git bisect it's a breeze: in the best case i can get a ~15 step kernel bisection done in 20-30 minutes, in an automated way. Even with manual help or when bisecting multiple, overlapping bugs, it's rarely more than an hour. In fact it's invaluable because there are bugs i would never even _try_ to debug if it wasn't for git bisect. In the past there were bug patterns that were immediately hopeless for me to debug - at best i could send the crash/bug signature to lkml and hope that someone else can think of something. And even if a bisection fails today it tells us something valuable about the bug: that it's non-deterministic - timing or kernel image layout dependent. So git bisect is unconditional goodness - and feel free to quote that ;-) _____________ Acknowledgments --------------- Many thanks to Junio Hamano for his help in reviewing

The text concludes the discussion on Git bisect by highlighting its usefulness in debugging and regression testing. It references BBChop, a tool that handles intermittent bugs, and suggests that a similar feature would be beneficial in Git. The conclusion is supported by a quote from Ingo Molnar, who praises Git bisect for saving him a significant amount of time and making debugging easier, even for complex and non-deterministic bugs.