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

[Jeff King <peff@peff.net>]

On Mon, Nov 23, 2020 at 09:41:05PM -0600, Felipe Contreras wrote:

> What we really need is something like:
> 
> 1. git pull # fail by default unless it's a fast-forward
> 2. git pull --merge # force a merge (unless it's a fast-forward,
> depending on pull.ff)
> 3. git pull --rebase # force a rebase (unless it's a fast-forward,
> depending on pull.ff)
> 
> Therefore, what we really want is "git pull --rebase" *ignore*
> "pull.ff=only" (a possible default) or ignore "pull.rebase=ff-only"
> (also another possible default).

Yep. After reading the first half of your mail, I started to respond
with the exact same thing. The key thing is letting the command-line
options override all of the related config. But I guess after reading to
the end that you don't actually like this. ;)

I do agree it would be more clear in the long run with a single option
(config and command-line) that makes it clear the values are mutually
exclusive. I'm just not sure if it's painful to get there without
breaking compatibility or introducing confusion in the meantime.

> It would be possible to do something like:
> 
>   if (!opt_rebase && (!opt_ff || !strcmp(opt_ff, "--ff-only")))
>     turn_default_behavior = 1;
> 
> But then how would we distinguish between "git pull", and "git pull
> --no-rebase" (aka. "git pull --merge" / "pull.rebase=false")?

I'm not sure what you mean. We can tell the difference between those
based on what we saw on the command-line option. I.e., your
"!opt_rebase" is really a tri-state, which allows something like:

  if (opt_rebase == REBASE_UNSET) {
          if (opt_ff == FF_UNSET)
	          opt_ff = ff_default; /* from config or baked-in */
	  }
	  opt_rebase = rebase_default;
  }

but I didn't look at the logic in git-pull.

That said...

> This is just too much unnecessary complication There's no need to
> entertain a dozen possible heuristics to avoid "pull.mode", none of
> which avoid breaking existing behavior.
> 
> Let's just accept we need push.mode, and then we can have everything:
> default, ff-only, merge, rebase.

I think it could be possible for the documentation to make clear the
interactions, especially if the feature is designed with eventual
deprecation of other options (e.g., if it says "pull.mode=ff-only" means
that pull.ff won't be examined, and there's no need to ever use it
anymore).

-Peff