Re: [PATCH v5 20/20] rebase: rename the two primary rebase backends

From: Elijah Newren <newren@gmail.com>
Date: Mar 12, 2020, 19:31 UTC
Message-ID: <CABPp-BHSAbJzWEsPSTM5Q6MPdmu4VSuOx-=6-MJkHUovg3_1=g@mail.gmail.com>
In-Reply-To: <20200312184621.GD120942@google.com>

On Thu, Mar 12, 2020 at 11:46 AM Jonathan Nieder <jrnieder@gmail.com> wrote:

Show 33 quoted lines

>
> Elijah Newren wrote:
> > On Thu, Mar 12, 2020 at 10:55 AM Jonathan Nieder <jrnieder@gmail.com> wrote:
>
> >> What if we support multiple merge.backend values, with semantics:
> >>
> >> - last recognized value wins
> >> - if no value is specified, use the default
> >> - if values are specified but none are recognized, error out with a
> >>   clear error message
> >>
> >> ?
> >
> > Sure, but...isn't that what we already do, other than maybe the
> > 'clear' part of step 3?
>
> Sorry for the lack of clarity.  I mean allowing
>
>         [rebase]
>                 backend = am
>                 backend = apply
>                 backend = futuristic
>
> with behavior
>
> - on "git" that understands am but not apply or futuristic, use the am
>   backend
> - on "git" that understands apply but not am or futuristic, use the
>   apply backend
> - on "git" that understands apply and futuristic, use the futuristic
>   backend
>
> That way, a single config file is usable on all three versions of Git.

Ah, gotcha, that makes sense though we'd need to make the thing multi-valued which is a bit late for 2.26. But we could at least extend the logic in that way for 2.27. Also, to further clarify, if they have

         [rebase]
                 backend = misspelled
                 backend = futuristic

then what should the error be?  A couple possibilities:

fatal: Unknown rebase backend: futuristic

fatal: Unknown rebase.backend config setting: futuristic

fatal: Unknown rebase.backend config setting; valid values are 'merge', 'apply'.

or should it be something else?