Subject: Re: [PATCH] rev-parse --parseopt: fix handling of optional arguments

From: Nicolas Vigier <[email-masked]>
Date: Wed, 16 Oct 2013 16:14:11 +0200

On Tue, 15 Oct 2013, Jonathan Nieder wrote:

> Junio C Hamano wrote:
> 
> > You just made these two that the user clearly meant to express two
> > different things indistinguishable.
> >
> > 	opt.sh -S
> >       opt.sh -S ''
> [...]
> > And that is exactly why gitcli.txt tells users to use the 'sticked'
> > form, and ends the bullet point with:
> >
> >    An option that takes optional option-argument must be written in
> >    the 'sticked' form.
> 
> Yes, another possibility in that vein would be to teach rev-parse
> --parseopt an OPTIONS_LONG_STICKED output format, and then parse with
> 
> 	while :
> 	do
> 		case $1 in
> 		--gpg-sign)
> 			... no keyid ...
> 			;;
> 		--gpg-sign=*)
> 			keyid=${1#--gpg-sign=}
> 			...
> 			;;
> 		esac
> 		shift
> 	done
> 
> This still leaves
> 
> 	opt.sh -S
> 	
> and
> 
> 	opt.sh -S''
> 
> indistinguishable.  Given what the shell passes to execve, I think
> that's ok.
> 
> The analagous method without preferring long options could work almost
> as well:
> 
> 	while :
> 	do
> 		case $1 in
> 		-S)
> 			... no keyid ...
> 			;;
> 		-S?*)
> 			keyid=${1#-S}
> 			...
> 			;;
> 		esac
> 		shift
> 	done
> 
> but it mishandles "--gpg-sign=" with empty argument.

I'm thinking about a patch to add the following two options to rev-parse :

--sticked-opt-args::
	Only meaningful in --parseopt mode. Tells the options parser to
	output options with optional arguments in sticked form. The
	default is to output them in non-sticked mode, which can be
	difficult to parse unambiguously.

--long-options::
	Only meaningful in --parseopt mode. Tells the options parser to
	output long option names, when available. The default is to use
	short option names when available.

When you want to handle optional args unambiguously, you use the
--sticked-opt-args option. And if you think an empty value can be
a meaningful value, you add the --long-options option to be able to
distinguish them.

Would it make sense ?