Re: [PATCH v2 02/14] pull: improve default warning

From: Felipe Contreras <felipe.contreras@gmail.com>
Date: Dec 5, 2020, 21:27 UTC
Message-ID: <CAMP44s2L24jhCG9ps72--ZiJkXUovR726jCf8JTLHAs0jV7Whg@mail.gmail.com>
In-Reply-To: <CABPp-BF4rXBOKsn8bG6y3QUEtNVV9K2Pk5NmwrU5818CqhRt_Q@mail.gmail.com>

On Sat, Dec 5, 2020 at 10:28 AM Elijah Newren <newren@gmail.com> wrote:

> On Fri, Dec 4, 2020 at 5:56 PM Felipe Contreras
> <felipe.contreras@gmail.com> wrote:

Show 17 quoted lines

> > Well, I already said I partly agree with you: in the --ff-only case
> > the suggestion should not be brought forward.
> >
> > But in the "git pull" default case, *today* it's doing a merge. If
> > uttering --merge and thus making the current behavior explicit instead
> > of implicit seems dangerous it's because it is. But not documenting it
> > doesn't make it any less dangerous.
>
> Sounds like we agree that the future should be ff-only-as-default.  I
> also agree with you that the primary problem is the current default
> behavior, and I'll agree with you that documenting the current default
> is okay.  However, I disagree that your wording here:
>
> +                       "If unsure, run \"git pull --no-rebase\".\n"
>
> does anything of the sort.  It does not mention that this is the
> default behavior the users would get if they provided no flags.

But that is not the warning, this is the warning:

  Pulling without specifying how to reconcile divergent branches is discouraged;
  you need to specify if you want a merge, a rebase, or a fast-forward.
  You can squelch this message by running one of the following commands:

    git config pull.rebase false  # merge (the default strategy)
    git config pull.rebase true   # rebase
    git config pull.ff only       # fast-forward only

  You can replace "git config" with "git config --global" to set a default
  preference for all repositories.
  If unsure, run "git pull --merge".
  Read "git pull --help" for more information.

This warning says:

1. There's 3 options: merge, rebase, fast-forward
2. merge is the default strategy
3. If unsure, specify --merge (the default strategy)

So taken altogether it does say what is the default strategy.

> More
> importantly, it makes a recommendation...and one that undercuts the
> point of the message.

So?

When boarding a plane the flight attendants do a safety demonstration that passengers should pay attention to. If one passenger is not paying attention (listening to music on headphones, and reading a book) what should the crew do?

1. Remove the passenger's headphones and force him to pay attention to
the safety demonstration
2. Let the passenger ignore the safety demonstration

Human beings are independent agents responsible for their own actions. You as a separate human being--a crew member--can argue that it's not in the best interest of the passenger to ignore the safety demonstration, and you may be right, but the passenger decisions are still the passenger's decisions, even if they are bad.

Do you think the crew should disregard the passenger's volition and force him to pay attention to the safety demonstration?

Show 7 quoted lines

> It makes it feel like the message shouldn't
> exist at all in any circumstances.  I even suspect that adding that
> sentence may undercut any efforts towards changing the default to
> ff-only-as-default.  While I'm a big fan of most of what you've done
> in this series, I will object to its merging for as long as this
> stays.  (I definitely don't have veto power or anything close to it,
> just stating what my opinion is.)

The current warning should not exist at all.

The complaint from Vít Ondruch [1] that reignited this series is a valid one. A *permanent* warning is not good. We should have a *temporary* warning with the express purpose of notifying users of an upcoming change.

If we have not yet decided on what should be the default (Junio seems to have casted some doubt on the consensus [2]), and we don't have a clear path forward to implement such change (we can't even tell users to use "pull.ff=only", since eventually it may be "pull.mode=ff-only"), then we must remove the warning.

It was a mistake to put a *permanent* warning before deciding to change the default.

So, there's two options:

1. We decide on a path forward and fix the warning so it *temporarily*
explains what will happen in the future
2. We remove the *permanent* warning

Since we are already here, we might as well take advantage of that warning and repurpose it. But in the meantime--while the git project decides what to do, and what configurations to suggest the users to change--we should at the very least waste as little as the user's time as possible, and give him/her a quick opt-out.

Yes, a quick opt-out defeats the purpose of a warning, but we must respect the users' volition. The user may be on a deadline trying to push some changes to production before the weekend, and after a system update be annoyed with this warning on every pull. The user may not have time to look at the warning, decide he wants to read the warning in the future, maybe next Monday, and thus not configure anything to silence it.

What's wrong with a user saying "I don't have time for this now, please tell me what to do for now, I'll look at the warning later"? If anything for those users the configuration is the wrong thing to do, because being in a hurry they just choose the first configuration and forget about the warning without actually looking at it (because they didn't have time), and it will not appear any more. By typing "git pull --merge" the user can get rid of the warning *for now*, but the next time he does "git pull" the warning will reappear, and at that time perhaps the user does have the time to read it, and look at the manpage.

Nobody likes their workflow to be interrupted and be forced to do anything.

I don't think my patches plus that suggestion for a quick opt-out are in any way worse than the current situation. If you think they are, then we'll just have to agree to disagree.

I quote the voice of Vít Ondruch, which I think represents the typical user: "please select any strategy considered more appropriate and stop warning me".

Cheers.

[1] https://lore.kernel.org/git/742df4c2-2bc5-8a4b-8de1-cd5e48718398@redhat.com/ [2] https://lore.kernel.org/git/xmqqh7p1fjml.fsf@gitster.c.googlers.com/

-- 
Felipe Contreras