Re: RFC - "git editlog" feature for fixing up local commit messages

[Avery Pennarun <apenwarr@gmail.com>]

On Mon, Mar 29, 2010 at 9:31 AM, Eric Raymond <esr@thyrsus.com> wrote:
> My editcomment script, as it exists, has a technical problem...the
> editor needs to be something like emacsclient that actually invokes in
> a different X window, otherwise whatever it writes to stdout will end
> up stuffed in the comment along with the text I actually wanted to put
> there.  The underlying problem is that git-filter-branch is sort of a
> nuclear-powered chainsaw - gets the job done, but in a way that is
> prone to messy side effects.  A more elegant implementation would
> probably need to tie deeper into the plumbing.

It ought to be easy to work around this; simply extract the log
message *before* filter-branch using something like

       git cat-file commit HEAD | tail -n +6 >msg.tmp

(I'm sure someone will correct me by providing a less revolting way to
extract the commit message, but it's somehow not coming to me right
now.)

Then launch $EDITOR to edit the message, then inside the
filter-branch, just use that file instead of launching the editor.

Alternatively, in case you want the option of editing *multiple*
commit messages at once, you could just redirect stdin/stdout to
/dev/tty.

A further option would be to extend git-rebase--interactive.sh (yes,
it's just a shell script) to take an option that makes a given commit
(or commits) 'reword' by default instead of 'pick'.  And maybe another
option to make git-rebase--interactive.sh not actually pop up an
editor before it starts running.  Then your editcommit script could
just be a thin wrapper around rebase with those options.

<insert obligatory wistful reference to git-sequencer> (I don't
actually know anything about git-sequencer.)

Have fun,

Avery