Re: [BUG REPORT] Git does not correctly replay bisect log

From: Lukáš Krejčí <lskrejci@gmail.com>
Date: Dec 6, 2018, 17:30 UTC
Message-ID: <5ab4e3fb2e22097753bde7702e67d6ce924283a2.camel@gmail.com>
In-Reply-To: <CAP8UFD3VCzEdtfRqi_d2ibPtTN0uocGW+CshY_5m16TW1_YUdw@mail.gmail.com>

On Thu, 2018-12-06 at 17:31 +0100, Christian Couder wrote:

Show 10 quoted lines

> > When Git replays the bisect log, it only updates refs/bisect/bad,
> > refs/bisect/good-*, refs/bisect/skip-* and reconstructs the log in
> > .git/BISECT_LOG. After that check_good_are_ancestors_of_bad() verifies
> > that all good commits are ancestors of the bad commit, and if not, the
> > message "Bisecting: a merge base must be tested" is printed and the
> > branch is switched to the merge base of the bad and all the good
> > commits.
> 
> I am not sure if you are talking about running `git bisect replay` or
> sourcing the log in the above.

I am talking about `git bisect replay`. The shell script, as far as I can see, only updates the references (ref/bisect/*) and never checks if the revisions marked as 'good' are ancestors of the 'bad' one. Therefore, $GIT_DIR/BISECT_ANCESTORS_OK file is never created.

The first time the ancestors are checked is in the helper (`git-bisect- -help --next-all`) that has only limited information from refs/bisect*.