Re: git-bisect(1) next after finding the commit

[Junio C Hamano <gitster@pobox.com>]

Jeff King <peff@peff.net> writes:

> On Fri, Oct 02, 2026 at 11:49:01PM +0200, Alejandro Colomar wrote:
>
>> Is there a plumbing command for retrieving the bisected commit after
>> a git-bisect(1) session has successfully found it (and of course before
>> resetting the session)?
>> 
>> I expected `git bisect next` would bring me to it, and then I'd rev-list
>> HEAD -1, but it doesn't bring me to it.
>
> I'm not 100% sure, but I think "git show bisect/bad" should work.
>
> As the bisection progresses, we advance a single refs/bisect/bad from
> the bottom of the range (the top is multiple refs/bisect/good-* refs).
> So at the end, it should point to the blamed commit.

The only code that gives "is the first .* commit" message is this bit
in bisect.c:

	if (oideq(bisect_rev, current_bad_oid)) {
		res = error_if_skipped_commits(tried, current_bad_oid);
		if (res)
			goto cleanup;
		printf("%s is the first '%s' commit\n", oid_to_hex(bisect_rev),
			term_bad);

it is fed bisect_rev only when it is the same as current_bad_oid,
which was read from "refs/bisect/bad".  So I think you are right.


[Footnote]

There is a last-step optimization that made me double check the
code, but the optimization is about not bothering to move HEAD and
not moving refs/bisect/bad pointer.

We have a three-topic branch X, X is at the tip, X~1 at the middle
and X-2 at the bottom.  X~3 is on the mainline.

----- X~3 ---- X~2 ---- X~1 ---- X

We found X~2 to be good. X is bad.

  $ git bisect start X X~2

We are asked to test X~1.

 * It turns out to be bad.  We move bisect/bad to X~1.  And then we
   report that X~1 is the first bad commit.

 * Or it turns out to be good.  Then we report that X is the first
   bad commit.  But we do not move HEAD and checkout X.