Re: [PATCH RFC] rebase: respect --ff-only option

From: Junio C Hamano <gitster@pobox.com>
Date: Jul 5, 2021, 19:23 UTC
Message-ID: <xmqqlf6kmup4.fsf@gitster.g>
In-Reply-To: <xmqqpmvwn1qp.fsf@gitster.g>

Junio C Hamano <gitster@pobox.com> writes:

Show 15 quoted lines

> Phillip Wood <phillip.wood123@gmail.com> writes:
>
>> Looking at origin/seen:builtin/pull.c we already check if we can
>> fast-forward and unconditionally merge in that case irrespective of
>> any '--rebase' option or pull.rebase config. It should be simple for
>> pull to error out if '--ff-only' is given and we cannot fast-forward.
>
> Excellent.
>
> Even though teaching even more special case on the "git pull" side
> makes me feel somewhat dirty, but I think it would be a small price
> to pay, and the end result would save an useless fork whose sole
> purpose is to make the integration step after fetch fail when "pull"
> can easily tell, as you said, that it ought to fail, so overall it
> would probably be a net win.

A tangent after thinking a bit more.

I do not think "pull.rebase=interactive" affects the "ff logic" at all. Rebasing integration rebuilds _your_ commits on the current branch on top of the tip of _their_ history, and if their history is a descendant of your history (i.e. the history fast-forwards), by definition, you do not have anything you need to rebuild on top of theirs, whether with the opportunity to make tweaks via "rebase -i" or without.

This observation does not change the conclusion at all, but I should have spoken after thinking X-<.

Thanks.