Bisect will let you find the big squash commit that caused the regression, but lots of the information about why the change happened was lost during the squash.

Bisect will let you find the big squash commit that caused the regression, but lots of the information about why the change happened was lost during the squash. Often it's sufficient to just know the broad feature that the change was in aid of, but you're out of luck if you're diagnosing anything subtle. Bisect works better with smaller commits.