Re: [PATCH/RFC] completion: complete all possible -no-<options>

[Duy Nguyen <pclouds@gmail.com>]

On Wed, Apr 18, 2018 at 5:43 AM, Junio C Hamano <gitster@pobox.com> wrote:
> So, the earlier mention of "clone --no-checkout" sounded about not
> losing this historical practice, but (desirabilty of magic number 4
> aside) this "show first handful of --no-foo" feature is not about
> historical practice but is forward looking, in the sense that you do
> not mark "important" negated options in the source, which would be a
> way to handle the histrical "clone --no-checkout", but let the
> machinery mechanically choose among --no-foo (with the stupid choice
> criterion "first four are shown").

Well you kinda mark important in the source too. --no-checkout for
exampled is declared as OPT_BOOL(0, "no-checkout"... and parse-options
code has to add the double-negative form --checkout back [1].

The "first four" is chosen after carefully examining all commands and
observing that none of them have more than 4 "important" --no-. But
yes it is questionable and I should be able to do better to separate
the favorable --no- from the other extra and most-of-the-time-useless
--no- options.

> That allows other commands to
> have many --no-foo form without overwhelming the choices, but I am
> not sure if it is much better than a possible alternative of only
> showing --no-foo for more "important" foo's when show_gitcomp() is
> asked to list all of things. It would certainly be a more involved
> solution, that might require an update to the way how the choices
> are precomputed (you'd end up having to keep a separate "use this
> list when completing '--no-'" in addition to the normal list).

I did think about this alternative and was still undecided. Suppose
that you have less than 4 "important" --no- options, showing some
extra ones to me does not really hurt anything and if we could show
more options (within the same screen space) we should. But on the
other hand maintaining this magic number could be a maintenance
nightmare... Yeah I think I'm shifting towards no magic number now.

[1] These double negative options will _always_ show up,  there is no
easy way to hide them because they don't start with --no-. But we
don't have a lot of options starting with "no-" so it's probably fine.
-- 
Duy