Re: git rebase: retain original head?

From: Markus Wiederkehr <markus.wiederkehr@gmail.com>
Date: Jan 9, 2019, 15:08 UTC
Message-ID: <CA+h-Bnvp3mrXBqqY+mdD36feOkx1EhnnQtDXrmPhyW4KzKb_3w@mail.gmail.com>
In-Reply-To: <nycvar.QRO.7.76.6.1901091501320.41@tvgsbejvaqbjf.bet>

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.

git init testrepo cd testrepo echo 1 > file && git add file && git commit -m "initial" echo 1 >> file && git commit -am "commit 1" # rev_commit_1=$(git rev-parse HEAD) echo 1 >> file && git commit -am "fixup! $(git rev-parse --short HEAD)" echo 1 >> file && git commit -am "commit 3" rev_orig_head=$(git rev-parse HEAD) GIT_EDITOR=: git rebase --autosquash -i HEAD~3 test $(git rev-parse ORIG_HEAD) = $rev_orig_head

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