A Broken Build Is Not a Bad Commit

I chased a regression through two months of history where half the commits wouldn't even compile. Here's the tool I wrote so it wouldn't happen again. - A few weeks ago I hit the kind of bug that ruins an afternoon: something that used to work didn’t anymore, and I had no idea when it broke. Not “yesterday”, not “in that one PR” — somewhere in the last month or two, buried in a stretch of history…