I see two different problems each with a different assumption (see the definition of "bisectable" in the email of Junio C Hamano):
1. (Current) Assume the entire history graph is bisectable. DO: Search where in the entire graph the first 'trait'/transition occurs. 2. (New) Assume only the graph between one good commit and one bad commit is bisectable. DO: Search where the first transition occurs in the graph between these two commits. It seems that the real world needs a solution also for the second problem (example if the good commit is the FIRST good commit of a feature or if the good commit is not the first good commit, but you definitely know, that it broke first somewhere in between the good and bad commit). I find the way to go as Oleg proposed is gittish enough (with a new parameter --strategy). Beside I would underline that also the second problem is a bisect problem, just for another graph, thus it makes perfect sense to extend 'git bisect' for this. Does that look reasonably?
