That approach works well for regressions. I’ve used it myself to track down a bug in chrome and, as you say, having no idea how to fix it, I could direct it to

That approach works well for regressions. I’ve used it myself to track down a bug in chrome and, as you say, having no idea how to fix it, I could direct it to the author via the bug tracker. In my case it was fixed within a couple of days. And obviously bisecting chrome is a slow process, but it only took a couple of hours. I find that most bugs don’t fall into that class, and for the most part, just sitting and picturing the paths back from the bug is enough to work out what’s going on. If you’re less familiar with the code you’ll want it in front of you to trace your way back. In general you can narrow the search space pretty quickly.