What follows is a summary of a time bisect saved a team I was on from a lot of pain. It's been a long time so I may have some details wrong, but the point shou

What follows is a summary of a time bisect saved a team I was on from a lot of pain. It's been a long time so I may have some details wrong, but the point should be clear. Years ago I worked at an e-commerce shop. One fine day we discovered that the checkout process had been broken in a very particular corner case at some point in the past several months. No one had any idea how it had happened. Most of the team was trying to work out what could have possibly gone wrong by staring intently at code in their IDEs and debuggers while stepping through reproductions. I thought, "everyone's already doing that - I'll try a bisect, since we have a reliable reproduction for this inscrutable weirdness." It took maybe twenty minutes before I could point to a < twenty-line change. The author of said change was flummoxed at the breakage, as it was nowhere near the actual checkout code, but a few minutes of the whole team staring at it revealed a classic piece of PHP spaghetti insanity that had managed to break the checkout process (I no longer recall the specific issue - might've been global variable name collision). I think it would have taken hours before we got to an answer without bisect. Granted, it only worked so well because of good commit hygiene (which I had trained everyone to use when I introduced git and code review to that team), but it showed quite clearly how useful good commit hygiene is when paired with bisect.