Re: [PATCH] parse-options: don't complete option aliases by default

[Philippe Blain <levraiphilippeblain@gmail.com>]

Hi Ævar,

Le 2021-07-15 à 12:16, Ævar Arnfjörð Bjarmason a écrit :
> 
> 
> I'm a bit biased here since I like --recursive better, but let's not
> drag that whole argument up again. I don't find the argument in
> bb62e0a99fc (clone: teach --recurse-submodules to optionally take a
> pathspec, 2017-03-17) convincing enough to have moved such a prominent
> use-case to a longer option name.
> 
> But, water under the bridge. Aside from that:
> 
> For me a Google search for "git clone --recursive" is ~40k results, but
> "git clone --recurse-submodules". The former links to various
> discussions/docs/stackoverflow answers, often --recurse-submodules isn't
> mentioned at all or as an aside.
> 
> I think it's unfortunate that we:
> 
>   1. Conflate whether something shows up in completion v.s. the
>      help. Given its prominence and that "git clone -h" is ~50 lines why
>      not note --recursive there.

As far as I understand (and tested), '--recursive' was listed in the short help but not the completion
before bb62e0a99f (clone: teach --recurse-submodules to optionally take a pathspec,
2017-03-17). At the time the completion did not use '--git-completion-helper'
and only '--recurse-submodules' was listed (since 5f072e0017 (completion: add option
'--recurse-submodules' to 'git clone', 2016-07-27)).

Starting from bb62e0a99f, it was not listed in the short help (because of PARSE_OPT_HIDDEN)
nor the completion (because it was still not listed).

Then starting from 5c387428f1 (parse-options: don't emit "ambiguous option"
for aliases, 2019-04-29), it started being listed in the short help AND
the completion again; in the short help because of the new code in usage_with_options_internal
and in the completion because of the way preprocess_options is implemented,
and at that time '--git-completion-helper' was used for '_git_clone'.

After my patch, it would still be listed in the short help, as "alias of --recurse-submodules",
but would not be listed by the completion (unless GIT_COMPLETION_SHOW_ALL is set).

> 
>   2. Don't have the completion aware of these aliases, i.e. "git clone
>      --rec<TAB>" before your chance offers a completion of both, that sucks,
>      we should fully complete the non-alias instead.

Indeed. That's my main motivation.

> 
>   3. Making it PARSE_OPT_HIDDEN "solves" #2 at the cost of hiding it in
>      "git help -h", and now this won't work, but did before:
> 
>          git clone --recursi<TAB>
> 
>      I.e. even if we didn't want to do #2 *and* wanted to hide it in the
>      usage output surely completing an unmbigous prefix is better, even
>      if it's a hidden option?

I agree that with my patch 'git clone --recursi<TAB>' does not complete to '--recursive'
(unless you've set GIT_COMPLETION_SHOW_ALL). But I'm not sure it's that big of
a deal (after all if you typed this far you only have two letters left :P)
But '--rec' will be sufficient to complete to '--recurse-submoduele', so
it's even less letters to type.

But this has nothing to do with PARSE_OPT_HIDDEN ('--recurse-submodules' is
not hidden and aliases are not hidden either). So I'm not sure what you mean...

> 
> Per-se none of this is a blocker or "we must fix this first" for this
> particular change, we have this in many existing cases.
> 
> I daresay there's no other alias that's in as wide a use in the wild, so
> we should think about this one particularly carefully though.
> 
> It's not fully clear from your commit message which of 1-3 you're aiming
> for, I think it's more of the "discourage its use".

As I wrote it's mainly #2, I'll update the commit message to be clearer.

> 
> Sure, fair enough, but PARSE_OPT_HIDDEN is not a 1=1 mapping to that,
> and can often lead to more user confusion.
> 
> E.g. the user has used --recursive for years, but can't even find it in
> -h (I also think it's a mistake to have entirely removed it from the
> docs, even if one agrees with its "deprecation" I'd say we should keep
> some "used to be called --recursive" note there).
> 

Yeah, maybe it should have stayed in the docs. Again, my patch does not remove
it from the short help.

Thanks for you comments!:)

Philippe.