Re: [PATCH 10/12] builtin/show-ref: explicitly spell out different modes in synopsis

[Patrick Steinhardt <ps@pks.im>]

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On Tue, Oct 24, 2023 at 03:39:28PM -0400, Eric Sunshine wrote:
> On Tue, Oct 24, 2023 at 9:11 AM Patrick Steinhardt <ps@pks.im> wrote:
> > The synopsis treats the `--verify` and the implicit mode the same. They
> > are slightly different though:
> >
> >     - They accept different sets of flags.
> >
> >     - The implicit mode accepts patterns while the `--verify` mode
> >       accepts references.
> >
> > Split up the synopsis for these two modes such that we can disambiguate
> > those differences.
> 
> Good. When reading [2/12], my immediate thought was that such a
> documentation change was needed.
> 
> > Signed-off-by: Patrick Steinhardt <ps@pks.im>
> > ---
> > diff --git a/Documentation/git-show-ref.txt b/Documentation/git-show-ref.txt
> > @@ -8,9 +8,12 @@ git-show-ref - List references in a local repository
> >  SYNOPSIS
> > -'git show-ref' [-q | --quiet] [--verify] [--head] [-d | --dereference]
> > +'git show-ref' [-q | --quiet] [--head] [-d | --dereference]
> >              [-s | --hash[=<n>]] [--abbrev[=<n>]] [--tags]
> >              [--heads] [--] [<pattern>...]
> > +'git show-ref' --verify [-q | --quiet] [-d | --dereference]
> > +            [-s | --hash[=<n>]] [--abbrev[=<n>]]
> > +            [--] [<ref>...]
> >  'git show-ref' --exclude-existing[=<pattern>]
> 
> What does it mean to request "quiet" for the plain `git show-ref`
> mode? That seems pointless and counterintuitive. Even though this mode
> may accept --quiet as a quirk of implementation, we probably shouldn't
> be promoting its use in the documentation. Moreover, the blurb for
> --quiet later in the document:
> 
>    Do not print any results to stdout. When combined with --verify,
>    this can be used to silently check if a reference exists.
> 
> should probably be rephrased since it currently implies that it may be
> used with modes other than --verify, but that's not really the case
> (implementation quirks aside).

Good point indeed, will change.

> This also raises the question as to whether an interlock should be
> added to disallow --quiet with plain `git show-ref`, much like the
> interlock preventing --exclude-existing and --verify from being used
> together. Ideally, such an interlock ought to be added, but I wouldn't
> be surprised to learn that doing so would break someone's existing
> tooling which insensibly uses --quiet with plain `git show-ref`.

Yeah, I also wouldn't go as far as this. The mutual exclusiveness for
`--exclude-existing` and `--verify` makes sense in my opinion because
the result is extremely misleading and may cause users to assume that
the wrong thing has happened.

I don't think that's necessarily true for `--quiet`. It may not make a
lot of sense to specify `--quiet` here, but it also doesn't quietly do
the wrong thing as in the other case.

Furthermore, we also don't have any interlocks for incompatible other
flags, either: git-show-ref(1) won't complain when passing any of the
mode-specific flags to the other modes. If we want to fix that I'd
rather defer it to a follow up patch series though. And as you said, I
would almost certainly expect there to be some kind of fallout if we did
this change.

Patrick

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