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Message-ID: <4517dfca6c4692b28c4914410f475d3f521cd230.camel@perches.com>
Subject: Re: [PATCH 1/4] checkpatch: fix multiple const * types
From:   Joe Perches <joe@perches.com>
To:     Antonio Borneo <borneo.antonio@gmail.com>,
        Andy Whitcroft <apw@canonical.com>
Cc:     linux-kernel@vger.kernel.org
Date:   Wed, 08 May 2019 07:51:40 -0700
In-Reply-To: <20190508122721.7513-1-borneo.antonio@gmail.com>
References: <20190508122721.7513-1-borneo.antonio@gmail.com>
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On Wed, 2019-05-08 at 14:27 +0200, Antonio Borneo wrote:
> Commit 1574a29f8e76 ("checkpatch: allow multiple const * types")
> claims to support repetition of pattern "const *", but it actually
> allows only one extra instance.
> Check the following lines
> 	int a(char const * const x[]);
> 	int b(char const * const *x);
> 	int c(char const * const * const x[]);
> 	int d(char const * const * const *x);
> with command
> 	./scripts/checkpatch.pl --show-types -f filename
> to find that only the first line passes the test, while a warning
> is triggered by the other 3 lines:
> 	WARNING:FUNCTION_ARGUMENTS: function definition argument
> 	'char const * const' should also have an identifier name
> The reason is that the pattern match halts at the second asterisk
> in the line, thus the remaining text starting with asterisk fails
> to match a valid name for a variable.
> 
> Fixed by replacing "?" (Match 1 or 0 times) with "*" (Match 0 or
> more times) in the regular expression.
> Fix also the similar test for types in unusual order.

It might be better to use a max match like {0,4} instead of *

perl is pretty memory intensive at multiple unrestricted matches
of somewhat complex patterns.