git@vger.kernel.org mailing list mirror (one of many)
 help / color / mirror / code / Atom feed
From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: George Spelvin <lkml@SDF.ORG>
Cc: Junio C Hamano <gitster@pobox.com>, git@vger.kernel.org
Subject: Re: Feature request: rebase -i inside of rebase -i
Date: Sat, 21 Mar 2020 11:51:10 +0100 (CET)	[thread overview]
Message-ID: <nycvar.QRO.7.76.6.2003211135380.46@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <20200320233528.GB19579@SDF.ORG>

Hi,

On Fri, 20 Mar 2020, George Spelvin wrote:

> On Fri, Mar 20, 2020 at 03:51:20PM -0700, Junio C Hamano wrote:
> > I thought that "git rebase -i" allows the todo file (i.e. list of
> > steps still to be performed) to be edited before continuing; would
> > your use case be supported by using that?
>
> Mostly, if I do it very carefully, which is why I thought it would
> be easy to add.
>
> I think I could manually add the commits to the start of the todo file,
> reset --hard to the old state, and rebase --continue.
>
> But cutting and pasting commit IDs from git log into the todo file,
> and putting fixup commits in the right place is annoyingly fiddly.
> That's exactly the sort of thing computers are good at.

FWIW I have a super-hacky work-around for this use case that I am using in
my automation of continuously rebasing Git for Windows' `master` onto the
four integration branches of git.git:

1. create a throw-away worktree without checking out the commit

2. fake-run a new `rebase -i` in that worktree, with a custom "editor"
   (which is actually the same script) that simply consumes the todo list,
   aborts the `rebase -i` in the worktree, then deletes the worktree, and
   then inserts that todo list in the original todo list.

3. continue the rebase

I never got around to implement that as a proper "nested" mode of `git
rebase -i`, but it should not be too hard. The user interface would
probably look somewhat like `git rebase -i --nested <arguments>...` and it
would _expect_ an active interactive rebase, and it would insert the todo
list into the existing one, at the beginning, with proper commenting, then
reset `HEAD` after the user edited the todo list.

My biggest caveat is that I had to force-exit the rebase at some stage
due to reasons I only vaguely remember. It had something to do with the
replacement cache not being updated when an `exec` is executed that adds a
replacement object via `git replace` [*1*]. This issue might have
_nothing_ to do with nested rebases, but as I said, my recollection is
vague.

There are a couple more concerns, of course, such as: what to do if the
user deletes the entire todo list (which is traditionally the only way to
abort a rebase)? My gut feeling is that it should go back to the
_previous_ version of the todo list.

Another big concern is what to do about `rebase.missingCommitsCheck`: with
nested rebases, this will get increasingly tricky. Like, imagine you are
rebasing 5 commits, the third of them results in merge conflicts, you
realize that it is obsolete and so is now the first, already rebased
commit. You do a nested rebase of the latest two commits to drop them, but
they don't have their original commit hashes any longer. So it gets a bit
finicky to keep track of what commit has been dropped on purpose and what
was forgotten to pick instead.

Ciao,
Dscho

Footnote *1*: to refresh my recollection, I would have to scour the
history of the automation script, see
https://github.com/git-for-windows/build-extra/commits/master/ever-green.sh

  reply	other threads:[~2020-03-21 10:51 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-20 22:30 Feature request: rebase -i inside of rebase -i George Spelvin
2020-03-20 22:51 ` Junio C Hamano
2020-03-20 23:35   ` George Spelvin
2020-03-21 10:51     ` Johannes Schindelin [this message]
2020-03-21 17:56       ` George Spelvin
2020-03-25 19:26         ` Johannes Schindelin
2020-03-26  0:18           ` George Spelvin
2020-03-28 14:25             ` Johannes Schindelin
2020-03-28 16:30               ` George Spelvin
2020-03-31  0:00                 ` George Spelvin
2020-03-31 10:57                   ` Philip Oakley
2020-03-31 13:36                     ` Phillip Wood
2020-04-01 16:43                       ` Philip Oakley
2020-04-07 15:54                         ` Phillip Wood
2020-04-04 12:17                   ` Johannes Schindelin
2020-04-04 12:39                 ` Johannes Schindelin
2020-04-04 17:41                   ` George Spelvin
2020-04-06 10:40                     ` Sebastien Bruckert
2020-04-06 15:24                       ` George Spelvin
2020-04-07  9:16                         ` Sebastien Bruckert
2020-04-07 19:03                           ` George Spelvin
2020-03-30 14:01               ` Philip Oakley
2020-03-30 18:18                 ` George Spelvin
2020-03-30 21:53                   ` Philip Oakley
2020-03-21  8:47 ` Johannes Sixt

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.7.76.6.2003211135380.46@tvgsbejvaqbjf.bet \
    --to=johannes.schindelin@gmx.de \
    --cc=git@vger.kernel.org \
    --cc=gitster@pobox.com \
    --cc=lkml@SDF.ORG \
    /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).