Re: [PATCH] Create '--merges-only' option for 'git bisect'
- Date: Thu, 12 Apr 2018 13:53:46 +0200 (DST)
- From: Johannes Schindelin <Johannes.Schindelin@xxxxxx>
- Subject: Re: [PATCH] Create '--merges-only' option for 'git bisect'
On Thu, 12 Apr 2018, Tiago Botelho wrote:
> On Thu, Apr 12, 2018 at 9:58 AM, Christian Couder
> <christian.couder@xxxxxxxxx> wrote:
> > On Thu, Apr 12, 2018 at 9:49 AM, Harald Nordgren
> > <haraldnordgren@xxxxxxxxx> wrote:
> >> I think it looks similar. But if I'm reading that thread correctly
> >> then there was never a patch created, right?
> > (It is customary on this mailing list to reply after the sentences we
> > reply to. We don't "top post".)
> > On the GSoC idea pages (like https://git.github.io/SoC-2018-Ideas/) we
> > have been suggesting "Implement git bisect --first-parent" and there
> > are the following related links:
> > https://public-inbox.org/git/20150304053333.GA9584@xxxxxxxx/
> > https://public-inbox.org/git/4D3CDDF9.6080405@xxxxxxxxx/
> > Tiago in Cc also tried at a recent London hackathon to implement it
> > and came up with the following:
> > https://github.com/tiagonbotelho/git/pull/1/files
> > I tried to help him by reworking his commit in the following branch:
> > https://github.com/chriscool/git/commits/myfirstparent
> Thank you for the cc Christian, I’ve been quite busy and was not able
> to work on the PR for quite some time.
> I intended to pick it back up again next week. If it is ok with Harald
> I would love to finish the PR that I started,
> since it is quite close to being finished (I think it was just specs
> missing if I am not mistaken).
That looks promising. Just like I suggested to Harald in another reply
[*1*] on this thread, you probably want to use `int flags` instead, and
turn `find_all` into BISECT_FIND_ALL in a preparatory commit.
Also, you will definitely want to add a test. Again, my reply to Harald
[*1*] should give you a head start there... You will want to imitate the
test case I outlined there, maybe something like:
# A - B - C - F
# \ \ / \
# D - E - G - H
[... 'setup' as in my mail to Harald ...]
test_expect_success '--first-parent' '
write_script find-e.sh <<-\EOF &&
case "$(git show --format=%s -s)" in
B|C|F) ;; # first parent lineage: okay
*) git show -s --oneline HEAD >unexpected;;
# detect whether we are "before" or "after" E
test ! -f E.t
git bisect start --first-parent HEAD A &&
git bisect run ./find-e.sh >actual &&
test_path_is_missing unexpected &&
grep "$(git rev-parse F) is the first bad commit" actual
Also, Tiago, reading through your patch (as on chriscool/git; do you have
your own fork? That would make it much easier to collaborate with you by
offering PRs), it looks more straight-forward than editing the commit_list
after the fact and adding magic weights ;-)
Except for one thing. I wonder why `bisect_next_all()` does not set
revs.first_parent_only after calling `bisect_rev_setup()`? You would still
need the changes in `count_distance()`, as it performs its own commit
graph traversal, but there is no need to enumerate too many commits in the
first place, right?
Harald, maybe --merges-only can be implemented on top of --first-parent,
with the `int flags` change I suggested?