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From: Junio C Hamano <junio@pobox.com>
To: Luc Van Oostenryck <lucvoo@kernel.org>
Cc: Ramsay Jones <ramsay@ramsayjones.plus.com>,
	 Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
	 Sparse Mailing-list <linux-sparse@vger.kernel.org>
Subject: Re: sparse regex error
Date: Wed, 17 Jul 2024 11:44:13 -0700	[thread overview]
Message-ID: <xmqqzfqf270i.fsf@gitster.g> (raw)
In-Reply-To: <uug4xslokvlxr6z24q52z4pt7nrtiimbzunz2gz3kpilk4kxts@7jljsksi6baq> (Luc Van Oostenryck's message of "Thu, 21 Dec 2023 00:13:38 +0100")

Luc Van Oostenryck <lucvoo@kernel.org> writes:

>>   $ git diff
>>   diff --git a/validation/restrict-array.c b/validation/restrict-array.c
>>   index 04bfdad9..86753b7d 100644
>>   --- a/validation/restrict-array.c
>>   +++ b/validation/restrict-array.c
>>   @@ -29,9 +29,19 @@ typedef unsigned long int size_t;
>>    
>>    extern int regexec (const regex_t *__restrict __preg,
>>                       const char *__restrict __string, size_t __nmatch,
>>   -                   regmatch_t __pmatch[__restrict_arr],
>>   +                   regmatch_t __pmatch[__restrict_arr __nmatch],
>>                       int __eflags);
>
> ...    
>
>> which, similarly to git, shows errors not on the declaration of the
>> regexec() function, but on each call site (about a dozen in git):
>> 
>>   $ ./sparse validation/restrict-array.c
>>   validation/restrict-array.c:32:56: error: undefined identifier '__nmatch'
>>   validation/restrict-array.c:32:56: error: bad constant expression type
>
> Yes, it's because __nmatch should be in the function's prototype scope but
> Sparse hasn't such a thing.
>
> The following patch is a bit ugly but should solve the problem here above.
> It's hasn't had much testing, only the testsuite.

The same breakage came up recently on the Git mailing list.

  https://lore.kernel.org/git/xmqqikx42c42.fsf@gitster.g/

The patch seems to fix the problem when locally applyed to the tip
at v0.6.4-67-g3a4c5743 (of course we have to add -Wno-vla in our
Makefile when invoking sparse).

Any plan to polish it to "unugly" it and merge?

Thanks.



      parent reply	other threads:[~2024-07-17 18:48 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-20  0:18 sparse regex error Ramsay Jones
2023-12-20 23:13 ` Luc Van Oostenryck
2023-12-21  1:45   ` Ramsay Jones
2024-07-17 18:44   ` Junio C Hamano [this message]

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