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From:   Jonathan Corbet <corbet@lwn.net>
To:     Aditya Srivastava <yashsri421@gmail.com>
Cc:     yashsri421@gmail.com, lukas.bulwahn@gmail.com,
        linux-kernel-mentees@lists.linuxfoundation.org,
        linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org
Subject: Re: [RFC] scripts: kernel-doc: fix array element capture in
 pointer-to-func parsing
In-Reply-To: <20210217145625.14006-1-yashsri421@gmail.com>
References: <20210217145625.14006-1-yashsri421@gmail.com>
Date:   Mon, 22 Feb 2021 14:33:32 -0700
Message-ID: <878s7flrdf.fsf@meer.lwn.net>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Aditya Srivastava <yashsri421@gmail.com> writes:

> Currently, kernel-doc causes an unexpected error when array element (i.e.,
> "type (*foo[bar])(args)") is present as pointer parameter in
> pointer-to-function parsing.
>
> For e.g., running kernel-doc -none on kernel/gcov/gcc_4_7.c causes this
> error:
> "Use of uninitialized value $param in regexp compilation at ...", in
> combination with:
> "warning: Function parameter or member '' not described in 'gcov_info'"

In the future, please quote error messages from the kernel verbatim.
You can trim irrelevant stuff before or after, but please do not edit
them in this way.  That helps me to understand what you are fixing, and
is also useful for anybody else who might be searching for a solution to
the same problem.

> Here, the parameter parsing does not take into account the presence of
> array element (i.e. square brackets) in $param.
>
> Provide a simple fix by adding square brackets in the regex, responsible
> for capturing $param.
>
> A quick evaluation, by running 'kernel-doc -none' on entire kernel-tree,
> reveals that no additional warning or error has been added or removed by
> the fix.
>
> Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
> Signed-off-by: Aditya Srivastava <yashsri421@gmail.com>
> ---
> * Applies perfectly over next-20210217
>
>  scripts/kernel-doc | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/scripts/kernel-doc b/scripts/kernel-doc
> index e046e16e4411..8b5bc7bf4bb8 100755
> --- a/scripts/kernel-doc
> +++ b/scripts/kernel-doc
> @@ -1553,7 +1553,7 @@ sub create_parameterlist($$$$) {
>  	} elsif ($arg =~ m/\(.+\)\s*\(/) {
>  	    # pointer-to-function
>  	    $arg =~ tr/#/,/;
> -	    $arg =~ m/[^\(]+\(\*?\s*([\w\.]*)\s*\)/;
> +	    $arg =~ m/[^\(]+\(\*?\s*([\w\[\]\.]*)\s*\)/;
>  	    $param = $1;
>  	    $type = $arg;
>  	    $type =~ s/([^\(]+\(\*?)\s*$param/$1/;
> -- 

...meanwhile, I have applied this one, thanks.

jon