Re: git rebase: retain original head?

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Jan 11, 2019, 10:42 UTC
Message-ID: <nycvar.QRO.7.76.6.1901111138530.41@tvgsbejvaqbjf.bet>
In-Reply-To: <CA+h-Bnvp3mrXBqqY+mdD36feOkx1EhnnQtDXrmPhyW4KzKb_3w@mail.gmail.com>

Hi Markus,

On Wed, 9 Jan 2019, Markus Wiederkehr wrote:

Show 10 quoted lines

> On Wed, Jan 9, 2019 at 3:05 PM Johannes Schindelin
> <Johannes.Schindelin@gmx.de> wrote:
> >
> > Having said that, it is an unintended regression in the built-in rebase.
> > Markus, could you come up with a minimal test case, preferably in the form
> > of a patch to t/t3415-rebase-autosquash.sh?
> 
> I don't think I'm familiar enough with the test code to be able to
> provide a good patch but the following code should illustrate the
> regression.

I think that you think you're too unfamiliar with the test code only because you have not had a look.

> git init testrepo
> cd testrepo
> echo 1 > file && git add file && git commit -m "initial"

test_commit initial

> echo 1 >> file && git commit -am "commit 1"

test_commit 1 initial.t

> # rev_commit_1=$(git rev-parse HEAD)
> echo 1 >> file && git commit -am "fixup! $(git rev-parse --short HEAD)"

test_commit "fixup! 1" initial.t

> echo 1 >> file && git commit -am "commit 3"

test_commit 3 initial.t

> rev_orig_head=$(git rev-parse HEAD)
> GIT_EDITOR=: git rebase --autosquash -i HEAD~3
> test $(git rev-parse ORIG_HEAD) = $rev_orig_head

test_cmp_rev $rev_orig_head ORIG_HEAD

I leave it to you to make the actual patch.

Ciao, Johannes

Show 14 quoted lines

> 
> In older versions of git this test succeeded, i.e. ORIG_HEAD pointed
> to the previous original head, $rev_orig_head. In git version 2.20.1
> ORIG_HEAD now points to the commit that got fixuped instead,
> $rev_commit_1.
> 
> In previous versions ORIG_HEAD only pointed somewhere else if "git
> reset" was invoked manually during the rebase operation. I'm not sure
> if this is desirable, maybe ORIG_HEAD should always point to the
> previous head after rebase completes, no matter what operations were
> run in between. What do you think?
> 
> Markus
>