Re: [PATCH v2 6/7] config: allow configuration of multiple hook error behavior

From: "brian m. carlson" <sandals@crustytoothpaste.net>
To: Duy Nguyen <pclouds@gmail.com>
Cc: "Git Mailing List" <git@vger.kernel.org>,
	"Jeff King" <peff@peff.net>,
	"Johannes Schindelin" <Johannes.Schindelin@gmx.de>,
	"Junio C Hamano" <gitster@pobox.com>,
	"Johannes Sixt" <j6t@kdbg.org>,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
	"Phillip Wood" <phillip.wood123@gmail.com>,
	"Jonathan Nieder" <jrnieder@gmail.com>
Subject: Re: [PATCH v2 6/7] config: allow configuration of multiple hook error behavior
Date: Wed, 15 May 2019 23:10:17 +0000	[thread overview]
Message-ID: <20190515231017.GM7458@genre.crustytoothpaste.net> (raw)
In-Reply-To: <CACsJy8BN32Jm62MQPLsRwKST8DDNZ7NxnJbsqBO3PJ0K2qU-Ng@mail.gmail.com>

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On Tue, May 14, 2019 at 08:20:10PM +0700, Duy Nguyen wrote:
> On Tue, May 14, 2019 at 7:24 AM brian m. carlson
> <sandals@crustytoothpaste.net> wrote:
> >
> > There are a variety of situations in which a user may want an error
> > behavior for multiple hooks other than the default. Add a config option,
> > hook.<name>.errorBehavior to allow users to customize this behavior on a
> 
> An alternative name is onError, probably more often used for event
> callbacks. But I don't know, maybe errorBehavior is actually better.

I'm going to use "errorStrategy", since we already have
submodule.alternateErrorStrategy.

> > per-hook basis. Provide options for the default behavior (exiting
> 
> should we fall back to hook.errorBehavior? That allows people to set
> global policy, then customize just a small set of weird hooks.

Sure, that sounds good.

> maybe stop-on-first-error (or if you go with the "onError" name, I
> think "stop" is enough). I know "stop on/after first hook" does not
> really make any sense when you think about it. Maybe stop-on-first is
> sufficient.
> 
> I was going to suggest strcasecmp. But core.whitespace (also has
> multiple-word-values) already sets a precedent on strcmp. I think
> we're good. Or mostly good, I don't know, we still accept False, false
> and FALSE.

I think with errorStrategy, "stop" is fine. Simpler is better.

I literally picked what Peff had suggested in his email (mostly because
I'm terrible at naming things), and I don't get the impression he spent
a great deal of time analyzing the ins and outs of the names before
sending. I could be wrong, though.

> > +                       behavior = HOOK_ERROR_STOP_ON_FIRST;
> 
> This is basically the logical "and" behavior in a C expression. Which
> makes me think if anybody's crazy enough to need the "or" counterpart
> (i.e. run hooks, expect failure, keep going until the first success).
> 
> I guess it's a crazy mode. We should not care about until a real use
> case shows up.

Yeah, I think that's unlikely to be the case. Nothing prevents us from
adding it later.

> > +               else if (!strcmp(value, "report-any-error"))
> 
> I couldn't guess based on this name alone, whether we continue or stop
> after the reporting part. The 7/7 document makes it clear though. So
> all good.

I'm open to hearing better suggestions if anyone has any.

> > diff --git a/run-command.c b/run-command.c
> > index 191d6f6f7e..70fb19a55b 100644
> > --- a/run-command.c
> > +++ b/run-command.c
> > @@ -1308,6 +1308,8 @@ int async_with_fork(void)
> >  #endif
> >  }
> >
> > +struct string_list hook_error_behavior = STRING_LIST_INIT_NODUP;
> 
> Maybe stick this in 'struct repository'. I know most config variables
> are still global. But I think we have to move/reorganize them at some
> point. Most may end up in 'struct repository'.

Okay, sounds fine.

> > +                       default:
> > +                               BUG("unknown hook error behavior");
> 
> maybe BUG(".. behavior %d", behavior);

Sure.
-- 
brian m. carlson: Houston, Texas, US
OpenPGP: https://keybase.io/bk2204

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