Re: [PATCH] various: disallow --no-no-OPT for --no-opt options

From: René Scharfe <l.s.r@web.de>
Date: Apr 19, 2017, 13:11 UTC
Message-ID: <b4eef4c1-cd5a-aa71-fc79-8af89dbe365d@web.de>
In-Reply-To: <CACBZZX6XWXjvDKeR+a1Ymb4csXgOKLiF==VkKLp5S9TRVQhgoA@mail.gmail.com>

Am 19.04.2017 um 09:00 schrieb Ævar Arnfjörð Bjarmason:

Show 15 quoted lines

> On Wed, Apr 19, 2017 at 12:29 AM, René Scharfe <l.s.r@web.de> wrote:
>> Setting PARSE_OPT_NONEG takes away the ability to toggle the affected
>> option.  E.g. git clone would reject --checkout.  Currently users can
>> specify --no- options as defaults in aliases and override them on the
>> command line if needed, with the patch that won't be possible anymore.
>>
>> PARSE_OPT_NONEG should only be used for options where a negation doesn't
>> make sense, e.g. for the --stage option of checkout-index.
> 
> That's a bad bug, I don't know whether to be surprised or not that we
> had no tests for this :)
> 
> I thought I was just disabling --no-no-checkout for --no-checkout, not
> --checkout, but didn't notice the subtleties of the special case
> handling for --no-* in parse-options.c, thanks.

I'm confused.  What's the bug here?

--no-no-checkout is undocumented; Jacob's patch addresses it. --no-checkout is the documented form. Negation allows --checkout to be used as well, with the opposite meaning to --no-checkout. Turning off negation with PARSE_OPT_NONEG forbids --checkout to be used.

Perhaps the issue is that a single line of documentation is not enough ("PARSE_OPT_NONEG: says that this option cannot be negated")?

René