Re: [PATCH v2 2/3] parse-options: make OPT_ARGUMENT() more useful

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 18, 2019, 02:47 UTC
Message-ID: <xmqq7ecw7vbb.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <20190315031553.GB28943@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

Show 13 quoted lines

>> +`OPT_ARGUMENT(long, &int_var, description)`::
>>  	Introduce a long-option argument that will be kept in `argv[]`.
>> +	If this option was seen, `int_var` will be set to one (except
>> +	if a `NULL` pointer was passed).
>
> So this effectively makes it into a "bool" that we keep. I think that's
> fine. It always uses NOARG, so it is not like we would ever need to see
> "we got --foo, and this is the argument it had".
>
> I did wonder if it was possible for "--no-foo" to trigger this (leaving
> the caller who looks at the int unsure if they saw "--foo" or
> "--no-foo"), but it seems that the parse-options code checks for
> OPTION_ARGUMENT before it ever looks at negation.

When a caller that needs to tell --no-foo and lack of any foo related option arises, we should be able to update the function further so that the caller can initialize the variable to -1 (unspecified) and make sure that 0 is left upon seeing --no-foo so it's not a show stopper, I guess.