I understand that reality is more complex than this, but git bisect That should identify the/your commit in (usually) < 10 tests. At which point the previous

I understand that reality is more complex than this, but git bisect That should identify the/your commit in (usually) < 10 tests. At which point the previous code is still intact. Or git blame and look at the problematic lines, see who changed it and when. Now look at the git log (filtered just for this file if you want) and identify the last changes to this part of code that way. More complex than just // timestamp, initials: Changed foo, commenting the following 100 lines out maybe, but makes the day to day code so much more readable.