Re: Can't squash merge with merge.ff set to false

From: Paul Smith <paul@mad-scientist.net>
Date: Jan 5, 2018, 20:26 UTC
Message-ID: <1515183976.21764.114.camel@mad-scientist.net>
In-Reply-To: <CAGyf7-FHyO9pkEFFguea+B+VMTodF=mg8wJNedvjYdL7e7ORqQ@mail.gmail.com>

On Fri, 2018-01-05 at 12:12 -0800, Bryan Turner wrote:

Show 16 quoted lines

> On Fri, Jan 5, 2018 at 11:59 AM, Robert Dailey <rcdailey.lists@gmail.com> wrote:
> > Not sure if this is intended or a bug, but with the following
> > configuration:
> > 
> > $ git config --global merge.ff false
> > 
> > I am not able to merge my topic branch into master with squash
> > option:
> > 
> > $ git checkout master
> > $ git merge --squash topic
> > fatal: You cannot combine --squash with --no-ff.
> > 
> > I'm not sure why a non-fast-forward merge would prevent a squash
> > merge, since by its very nature a squashed merge is not a fast
> > forward merge (or maybe it is if you only have one commit).

Hah! I was just thinking of checking the latest Git RC I built yesterday to see if this pet peeve of mine has been fixed yet. I guess not!

> The easiest way to move forward is probably to pass "--ff" on the
> command line to override the config, when you're using "--squash".

That's what we always have to do. Very annoying; we use squash-merge extensively but also want to require ff merge by default.

Show 7 quoted lines

> As for why the two aren't allowed together, my assumption would be
> because if you're only squashing a single commit "--squash" and that
> commit is fast-forward from the target, a new commit is not created
> and instead the target branch is fast-forwarded. With "--no-ff", it's
> questionable what "--squash" should do in that case. Fast-forward
> anyway? Rewrite the commit simply to get new committer details and
> SHA-1?

If it only failed when you were squash-merging a single commit that was also fast-forwardable, I guess that would be one thing. But even if I have multiple commits and I want to squash-merge them, which clearly is a separate operation giving different results, I get this error.

I don't think Git should try to be clever here (if that's what it's doing--I always assumed it was just a missing configuration case in the error check). If I asked for a squash-merge then Git should give me a squash merge.

So in answer to your question, --squash should give me a squash merge and the setting of --ff / --no-ff should be completely ignored, as it's irrelevant.

My $0.02.