Re: [PATCH 3/3] commit: add an option the reword HEAD

From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: Phillip Wood <phillip.wood123@gmail.com>
Cc: Phillip Wood via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org, Phillip Wood <phillip.wood@dunelm.org.uk>
Subject: Re: [PATCH 3/3] commit: add an option the reword HEAD
Date: Wed, 23 Sep 2020 22:42:56 +0200 (CEST)	[thread overview]
Message-ID: <nycvar.QRO.7.76.6.2009232241140.5061@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <41dcb8cb-8e43-04ce-2ddd-d69c765ee327@gmail.com>

Hi Phillip,

On Wed, 23 Sep 2020, Phillip Wood wrote:

> On 23/09/2020 11:22, Johannes Schindelin wrote:
> >
> > On Mon, 21 Sep 2020, Phillip Wood via GitGitGadget wrote:
> >
> > > From: Phillip Wood <phillip.wood@dunelm.org.uk>
> > >
> > > If one notices a typo in the last commit after starting to stage
> > > changes for the next commit it is useful to be able to reword the last
> > > commit without changing its contents. Currently the way to do that is
> > > by specifying --amend --only with no pathspec which is not that
> > > obvious to new users (so much so that before beb635ca9c ("commit:
> > > remove 'Clever' message for --only --amend", 2016-12-09) commit
> > > printed a message to congratulate the user on figuring out how to do
> > > it). If the last commit is empty one has to pass --allow-empty as well
> > > even though the contents are not being changed. This commits adds a
> > > --reword option for commit that rewords the last commit without
> > > changing its contents.
> >
> > I would like to explain the idea I tried to get across when I proposed to
> > implement support for `reword!` (and `--reword`) because I feel that it
> > will change the design of this patch in a rather big way.
> >
> > First of all, let me explain the scenario in which I long for the
> > `--reword` option: I maintain several patch thickets, the most obvious one
> > being Git for Windows' patch thicket that is merge-rebased [*1*] onto
> > every new Git version.
> >
> > At times, I need to adjust a commit message in that patch thicket. It
> > would be quite wasteful to perform a full merge-rebase, therefore I
> > typically call `git commit --squash <commit> -c <commit>`, copy the
> > oneline, paste it after the `squash!` line (surrounded by empty lines), and
> > then reword the commit message. When the next Git version comes out, I do
> > a merging-rebase, and when the editor pops up because of that `squash!`
> > oneline, I remove the now-obsolete version(s) of the commit message.
> >
> > Obviously, I have to be careful to either also pass `--only` (which I
> > somehow managed to learn about only today) or I have to make sure that I
> > have no staged changes. In practice, I actually specify a bogus path,
> > which has the same effect as `--only`.
> >
> > What I would actually rather have is the `--reword` option: `git commit
> > --reword <commit>`. In my mind, this would _add_ a new, "empty" commit,
> > letting me edit the commit message of the specified commit, and using that
> > as commit message, prefixed with the line `reword! <oneline>`.
> >
> > This, in turn, would need to be accompanied by support in the interactive
> > rebase, to perform the desired reword (which is admittedly quite a bit
> > different from what the way the todo command `reword` works).
> >
> > With that in mind, I would like to caution against the design of your
> > current patch, because it would slam the door shut on the way I would like
> > `--reword` to work.
>
> I'm keen to have an easy way to reword HEAD and a way to implement your
> reword! idea.
>
> I posted a comment on your gitgitgadget issue about reword! and drop![1]
> pointing to some patches[2] that implement the reword! idea as amend!. I think
> we want to be able to  fixup a commit and reword it at the same time which is
> way I chose the name amend! rather than reword! The implementation currently
> changes `git commit --amend` to take an optional commit which isn't ideal. I
> wonder if calling it revise! would be better then we could have `git commit
> --reword` to reword HEAD and `git commit --revise <commit>` to create a commit
> that will reword and fixup <commit> when the user runs `git rebase -i
> --autostash`. fold! is another possibility.
>
> I don't think this patch series stops us implementing something for rebase but
> it would mean we couldn't use the name reword! unless we allow `git commit
> --reword` to take an optional commit which I'm not that keen on.
>
> What do you think to an alternative name?

I am really worried that the proliferation of confusingly similar options
will increase Git's reputation for being awfully hard to use.

Ciao,
Dscho