Re: Pick the right default and stop warn on `git pull`

From: Felipe Contreras <felipe.contreras@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: "Alex Henrie" <alexhenrie24@gmail.com>,
	"Jeff King" <peff@peff.net>, "Theodore Y. Ts'o" <tytso@mit.edu>,
	"Vít Ondruch" <vondruch@redhat.com>,
	"Git mailing list" <git@vger.kernel.org>
Subject: Re: Pick the right default and stop warn on `git pull`
Date: Wed, 25 Nov 2020 19:02:14 -0600	[thread overview]
Message-ID: <CAMP44s0M00sBvdjD0jc0X=1=PJepC5fNndw73sceOpbDCw5dFQ@mail.gmail.com> (raw)
In-Reply-To: <xmqq7dqagtgx.fsf@gitster.c.googlers.com>

On Tue, Nov 24, 2020 at 6:39 PM Junio C Hamano <gitster@pobox.com> wrote:
>
> Alex Henrie <alexhenrie24@gmail.com> writes:
>
> > We'd only need a warning if both pull.ff and pull.rebase are unset,
> > since that's the only situation where the behavior would change. And
> > providentially, we already have a warning in that exact case, although
> > we should probably tweak it to explain what the new behavior is going
> > to be :-)
>
> If we were starting "git pull" from scratch without any existing
> configuration and command line options, pull.mode might present a
> simpler end user experience, but I have to say that pull.ff and
> pull.rebase that are fairly well ingrained in docs and users' minds,
> the above plan sounds like a better option to reduce the cognitive
> overhead for users.

Is it? From forums, blogs, and answers in Stack Overflow what I mostly
see is "do not do git pull".

> >> And yes, it should be possible to do what you suggest, but have you
> >> tried? I suspect both the code and the documentation would be quite
> >> convoluted.
> >
> > Yes, I have written a very simple patch that implements the behavior
> > that I am suggesting. I will send it to the mailing list later
> > tonight.
>
> Let's see how well the comparison between two approaches play out.
> Thanks.

I tried to remove pull.mode from my patch series, and it mostly works,
except if you:

1. Have "pull.ff=only"
2. Do a "git pull --no-rebase"

When you have "pull.mode=ff-only", doing "git pull --no-rebase" ("git
pull --merge") that mode is overridden, and the merge succeeds.

If you have "pull.ff=only", you would have to do "git pull --no-rebase
--no-ff" for the merge to succeed, which I don't think should be the
default.

We could change the semantics of "pull.ff=only", but that would break
existing behavior, and it starts to get convoluted.

Cheers.

-- 
Felipe Contreras