Re: [PATCH] pull: allow branch.<name>.rebase to override pull.ff=only

From: D. Ben Knoble <ben.knoble+github@gmail.com>
Date: Feb 10, 2025, 20:26 UTC
Message-ID: <CALnO6CDZ=rq_eZESzi++VFk081ddosHMpKQV4QHNFJbnsOMAzg@mail.gmail.com>
In-Reply-To: <CAMMLpeQvJUZJuwvK-H=M_FFedpgazGOPH=7wvPCg3U8RrxEtkA@mail.gmail.com>

On Thu, Feb 6, 2025 at 9:36 PM Alex Henrie <alexhenrie24@gmail.com> wrote:

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>
> On Tue, Feb 4, 2025 at 8:11 PM D. Ben Knoble
> <ben.knoble+github@gmail.com> wrote:
> >
> > When running "git pull" with the following configuration options, we
> > fail to merge divergent branches:
> >
> > - pull.ff=only
> > - pull.rebase (unset)
> > - branch.<current_branch>.rebase=true
> >
> > Yet it seems that the user intended to make rebase the default for the
> > current branch while using --ff-only for non-rebase pulls.
>
> You make an interesting point. The idea is that more specific options
> override less specific options. In this case, "fast-forward only" is
> more specific than "rebase" (because rebasing might or might not
> fast-forward), but "my branch" is also more specific than "all
> branches". So which option should win? 🤔

Precisely! I think "my branch" is most specific here, but Junio's argument is (if I understand it) that pull.ff=only is _stronger_, regardless of specificity.

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>
> On Wed, Feb 5, 2025 at 2:14 PM D. Ben Knoble
> <ben.knoble+github@gmail.com> wrote:
>
> > Is there, then, an existing combination that means roughly to treat
> > `git pull` with no other options like this:
> > - if not rebasing, forbid merging and be equivalent to --ff-only
> > - if rebasing is requested (because of branch.name.rebase or --rebase
> > or …?), allow it
>
> I think what we're missing is a branch.<name>.ffOnly option to make a
> particular branch fast-forward only. Such an option would be
> especially useful for the master branch, but you could set it on all
> of your branches except the ones that you want to rebase. We could
> even have a branch.autoSetupFfOnly option to turn on ffOnly
> automatically for new branches.

That is probably something that is missing, and might solve the problem, but I don't know that these in particular are something I need (read: want to implement).

How do you (and Junio, and others) feel about pull.ff=onlyUnlessOverridden? The meaning would be "like --ff-only except when branch.<name>.rebase says otherwise."

The name of the value can be workshopped (I initially thought of "override" as a short value, but it may be too short to convey its intended meaning). Perhaps "onlyOr[Branch]Rebase"?

I think this would be a smaller change that meets my needs without changing the meaning of ff=only.

>
> -Alex