Re: What's cooking in git.git (Apr 2017, #04; Wed, 19)

From: Christian Couder <christian.couder@gmail.com>
Date: Apr 21, 2017, 12:29 UTC
Message-ID: <CAP8UFD19DVqQLHBta74uLcFPwJaRUKF8Ppmnhct5ub=OkKSqCQ@mail.gmail.com>
In-Reply-To: <alpine.DEB.2.20.1704211135430.3480@virtualbox>

On Fri, Apr 21, 2017 at 11:50 AM, Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:

Show 5 quoted lines

>
> Since that "let's aggregate everything and only push out the final result
> at the end of the day" approach does not really allow the Continuous
> Testing to identify problems associated with individual topic branches, I
> have another job that bisects the breakages

Great!

> (with all associated problems
> I reported earlier, as you apply some patches on top of really ancient
> commits and bisect wants to test all merge bases first)

First bisect should ask you to test merge bases only if there are "good" commits that are not ancestors of the "bad" commit. So I don't know how you want to bisect, but it seems to me that you could just go back to a previous know "good" commit when the one you have is not an ancestor of the "bad" commit. This would get rid of the whole merge base problem.

Second yeah there is probably an old bug in bisect there. In theory in most cases bisect should ask you to test only one merge base, as:

- if the merge base is "bad", it means that the bug has been fixed
between the merge base and your "good" commit, and bisecting will
stop,
- if the merge base is "good", it means that all the merge bases that
are ancestor of this merge base are also good, so there is no need to
test them

But that theory can work only if bisect is asking you to test a merge base that is a descendant of many (if not all the other merge bases), but unfortunately I don't think bisect is smart enough for that yet.

> because the
> required time *definitely* would let Travis time out all the time. Those
> bisect results are even less visible than the Travis results, see e.g.
> https://github.com/git/git/commit/2e3a8b9035a#commitcomment-21836854.

Nice that they exists though!