On Wed, Apr 04, 2018 at 11:48:42AM -0400, Derrick Stolee wrote:
> > diff --git a/commit.c b/commit.c
> > index 858f4fdbc9..2566cba79f 100644
> > --- a/commit.c
> > +++ b/commit.c
> > @@ -1059,12 +1059,19 @@ int in_merge_bases_many(struct commit *commit, int
> > nr_reference, struct commit *
> > {
> > struct commit_list *bases;
> > int ret = 0, i;
> > + uint32_t min_generation = GENERATION_NUMBER_UNDEF;
> > if (parse_commit(commit))
> > return ret;
> > - for (i = 0; i < nr_reference; i++)
> > + for (i = 0; i < nr_reference; i++) {
> > if (parse_commit(reference[i]))
> > return ret;
> > + if (min_generation > reference[i]->generation)
> > + min_generation = reference[i]->generation;
> > + }
> > +
> > + if (commit->generation > min_generation)
> > + return 0;
> > bases = paint_down_to_common(commit, nr_reference, reference);
> > if (commit->object.flags & PARENT2)
>
> This patch may suffice to speed up 'git branch --contains' instead of
> needing to always use the 'git tag --contains' algorithm as considered in
> [1].
I'd have to do some timings, but I suspect we may want to switch to the
"tag --contains" algorithm anyway. This still does N independent
merge-base operations, one per ref. So with enough refs, you're still
better off throwing it all into one big traversal.
-Peff
