On Fri, 9 Feb 2018, Philip Oakley wrote: > From: "Robert P. J. Day" <rpjday@xxxxxxxxxxxxxx> > > On Fri, 9 Feb 2018, Philip Oakley, CEng MIET wrote: > (apologies for using the fancy letters after the name ID...) > > > >> From: "Robert P. J. Day" <rpjday@xxxxxxxxxxxxxx> > >> > > >> > writing a short tutorial on "git bisect" and, all the details > >> > of special exit code 125 aside, if one wanted to locate the > >> > first unbuildable commit, would it be sufficient to just run? > >> > > >> > $ git bisect run make > >> > > >> > as i read it, make returns either 0, 1 or 2 so there doesn't > >> > appear to be any possibility of weirdness with clashing with a > >> > 125 exit code. am i overlooking some subtle detail here i > >> > should be aware of? thanks. > >> > >> In the spirit of pedanticism, one should also clarify the word > >> "first", in that it's not a linear search for _an_ unbuildable > >> commit, but that one is looking for the transition between an > >> unbroken sequence of unbuildable commits, which transitions to > >> buildable commits, and its the transition that is sought. (there > >> could be many random unbuildable commits within a sequence in > >> some folks' processes!) > > > > quite so, i should have been more precise. > > > > rday > > The other two things that may be happening (in the wider bisect > discussion) that I've heard of are: > 1. there may be feature branches that bypass the known good starting > commit, which can cause understanding issues as those side > branches that predate the start point are also considered > potential bu commits. ok, but let's make sure i understand what defines a possible commit that "introduces" the bug. if i define two bisection commits <good> and <bad>, then i've always assumed that what i'm after is a commit <X> for which: 1) <X> is reachable from <bad> 2) <good> is reachable from <X> this seems fairly obvious. now, as you suggest, it's possible that the "bug" was introduced on a feature branch that bypasses my choice of <good> but, at *some* point, that feature branch would have to be merged to the point where it was now reachable from <bad> and, in the context of bisection, *that* merge commit would represent where the bug was introduced, no? rday
