Re: [RFC/PATCH 5/6] revert: add --ff option to allow fast forward when cherry-picking

From: Paolo Bonzini <bonzini@gnu.org>
Date: Feb 1, 2010, 14:29 UTC
Message-ID: <4B66E53D.8050204@gnu.org>
In-Reply-To: <c07716ae1002010443p4e0443feke14e5f877584640f@mail.gmail.com>

On 02/01/2010 01:43 PM, Christian Couder wrote:

> Maybe it could be the default, but in this case it should be made
> compatible with -n option (and perhaps other options) for backward
> compatibility, and this would probably need more involved changes.

A better objection is that GIT_COMMITTER_* is respected by |git cherry-pick" but not by "git cherry-pick --ff", and that even without setting the variables, "git cherry-pick" will pick a new commit date but "git cherry-pick --ff" wouldn't. The latter, I think is the only difference that is worth pondering further.

My impression is that a user would never have any problem with fast-forwarding. For scripts probably the same is true (the typical scenario for scripts is probably very similar to what "git rebase -i" does), but it can still be a potential backwards-incompatibility in case the script is *expecting* cherry-picking to generate a new SHA1. How broken can we consider this expectation?

That said, to reply to your question, of course -n would disable it, and so would -x, -s and possibly -e. But then, the same applies to --ff: your patch forbids "-n --ff", but -x, -s and -e would need the same treatment.

Note that "-e --ff" would error out; however if --ff would be the default, "-e" would probably choose between fast-forward and non-fast-forward depending on whether the commit message was edited.

Paolo