From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: Phillip Wood <phillip.wood123@gmail.com>
Cc: "SZEDER Gábor" <szeder.dev@gmail.com>,
git@vger.kernel.org, "Junio C Hamano" <gitster@pobox.com>
Subject: Re: minor interactive rebase regression: HEAD points to wrong commit while rewording
Date: Wed, 14 Aug 2019 22:45:22 +0200 (CEST) [thread overview]
Message-ID: <nycvar.QRO.7.76.6.1908142241080.656@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <2a7d69a9-cb3e-eb84-188f-5713876f6d78@gmail.com>
[-- Attachment #1: Type: text/plain, Size: 3066 bytes --]
Hi,
On Mon, 12 Aug 2019, Phillip Wood wrote:
> On 12/08/2019 18:50, SZEDER Gábor wrote:
> >
> > When running interactive rebase to reword a commit message, I would
> > expect that the commit whose message I'm rewording is checked out.
> > This is not quite the case when rewording multiple subsequent commit
> > messages.
> >
> > Let's start with four commits, and start an interactive rebase from
> > the first commit:
> >
> > $ git log --oneline
> > 5835aa1 (HEAD -> master) fourth
> > 64ecc64 third
> > d5fad83 second
> > 384b86f first
> > $ git rebase -i 384b86f
> >
> > Update the instruction sheet to edit the log messages of two
> > subsequent commits:
> >
> > r d5fad83 second
> > r 64ecc64 third
> > pick 5835aa1 fourth
> >
> > Now, after the editor opens up the second commit's log message, start
> > a new terminal and check where HEAD is pointing to:
> >
> > ~/tmp/reword (master|REBASE-i 1/3)$ head -n1 .git/COMMIT_EDITMSG
> > second
> > ~/tmp/reword (master|REBASE-i 1/3)$ git log --oneline -1
> > d5fad83 (HEAD) second
> >
> > So far so good.
>
> Because the sequencer can fast-forwarded to second from first it does that and
> then run 'commit --amend' to do the reword.
>
> > Save the updated commit message, and after the editor opens up the
> > third commit's log message, check again where HEAD is pointing to now:
> >
> > ~/tmp/reword (master +|REBASE-i 2/3)$ head -n1 .git/COMMIT_EDITMSG
> > third
> > ~/tmp/reword (master +|REBASE-i 2/3)$ git log --oneline -1
> > c3db735 (HEAD) second - updated
>
> As second has been updated the sequencer cannot fast-forward to third so it
> cherry-picks third and then passes --edit when it runs 'git commit' to commit
> the cherry-pick. HEAD is updated once the reworded commit has been created.
>
> I think the scripted rebase always ran cherry-pick and then ran 'commit
> --amend' afterwards if the commit was being reworded. The C implementation is
> more efficient as it avoids creating an redundant commit but has the side
> effect that HEAD is not updated before the reword which was surprising here.
Indeed, that was even intentional.
> I don't think I've ever looked at HEAD while rewording, my shell prompt gets
> the current pick from .git/rebase-merge/done so does not look at HEAD. While
> it might seem odd if the user looks at HEAD it's quite nice not to create a
> new commit only to amend it straight away when it's reworded. We have
> REBASE_HEAD which always points to the current pick - HEAD is also an
> unreliable indicator of the current pick if there are conflicts.
That is interesting; I would never have thought about scripting around
`reword`.
However, I am reluctant to accept the performance impact: in the long
run, I would love to have an interactive rebase that actually only
updates `HEAD` (and the worktree) when interrupting the rebase (via
`break` or `edit`), and `reword` does not qualify for "interrupting" in
my mind.
Ciao,
Dscho
next prev parent reply other threads:[~2019-08-14 20:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-12 17:50 minor interactive rebase regression: HEAD points to wrong commit while rewording SZEDER Gábor
2019-08-12 18:17 ` Junio C Hamano
2019-08-12 18:56 ` SZEDER Gábor
2019-08-12 20:28 ` Phillip Wood
2019-08-14 20:45 ` Johannes Schindelin [this message]
2019-08-14 21:40 ` SZEDER Gábor
2019-08-14 21:20 ` SZEDER Gábor
2019-08-15 13:47 ` Phillip Wood
2019-08-15 16:36 ` Junio C Hamano
2019-08-15 16:54 ` Junio C Hamano
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=nycvar.QRO.7.76.6.1908142241080.656@tvgsbejvaqbjf.bet \
--to=johannes.schindelin@gmx.de \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=phillip.wood123@gmail.com \
--cc=szeder.dev@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).