Re: [PATCH] pull: abort if --ff-only is given and fast-forwarding is impossible

[Felipe Contreras <felipe.contreras@gmail.com>]

Junio C Hamano wrote:
> Alex Henrie <alexhenrie24@gmail.com> writes:
> 
> > Sorry, I misspoke. I was thinking of the case where fast-forwarding is
> > impossible.
> 
> When we cannot fast-forward (i.e. we have our own development that
> is not in the tip of their history),
> 
>  --ff-only would cause the operation fail
>  --ff would become no-op (as it merely allows fast-forwarding)
>  --no-ff would become no-op (as it merely forbids fast-forwarding)
> 
> and the latter two case, we'd either merge or rebase (with possibly
> specified mode like --preserve-merges).  I thought the current
> documentation is already fairly clear on this point?

Correct. But the documentation says absolutly nothing about
`--ff-only --rebase`.

> > If fast-forwarding is possible, --ff-only already effectively
> > implies --no-rebase, and we might want to make that explicit in
> > the documentation.
> 
> When we fast-forward (i.e. their history is descendant from ours,
> and the user did not give --no-ff), it does not matter if it is done
> using the merge backend, the rebase backend, or by the "git pull"
> wrapper. The end user does not care.  The end result is that the tip
> of the branch now points at the tip of the history we pulled from
> the other side and that is all what matters.
> 
> So, from that point of view, I do not think we want to say rebase or
> merge or anything else for such a case in the documentation.

Correct again. But currently the only way a fast-forward is possible is
by doing `git merge --ff-only`, which is a merge done in a fast-forward
way.

If we add my proposed `git fast-forward` [1], then the documentation
could be updated to say that --ff-only does a `git fast-forward`, and
thus there's no need for `git merge` (or `git rebase`).

[1] https://lore.kernel.org/git/20210705123209.1808663-4-felipe.contreras@gmail.com/

-- 
Felipe Contreras