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Subject: Re: [PATCH] checkpatch: do not allow using -f/--file option without
 a filename
From:   Joe Perches <joe@perches.com>
To:     Dwaipayan Ray <dwaipayanray1@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     linux-kernel@vger.kernel.org, lukas.bulwahn@gmail.com
Date:   Sat, 05 Jun 2021 12:32:19 -0700
In-Reply-To: <20210605191754.28165-1-dwaipayanray1@gmail.com>
References: <20210605191754.28165-1-dwaipayanray1@gmail.com>
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On Sun, 2021-06-06 at 00:47 +0530, Dwaipayan Ray wrote:
> When checkpatch is run without a filename, it reads from stdin.
> But if --file option is used along with that, it may generate
> false positives.
> 
> Consider the following test file:
> $cat test.c
> int x = a - b;
> 
> $cat test.c | ./scripts/checkpatch.pl -f
> WARNING: It's generally not useful to have the filename in the file
> +int x = a - b;
> 
> This is a false positive and occurs because $realfile is set to "-".
> Also since checkpatch relies on the file's extension to run specific
> checks for c files, assembly files, etc, most of the checks are
> not run as well.
> 
> So it is better to disable -f/--file option when checkpatch is
> run without a filename.

That's a reasonable commit message, thanks.

> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -331,6 +331,7 @@ help(0) if ($help);
> ?
> 
> ?die "$P: --git cannot be used with --file or --fix\n" if ($git && ($file || $fix));
> ?die "$P: --verbose cannot be used with --terse\n" if ($verbose && $terse);
> +die "$P: -f/--file requires at least one filename\n" if ($file && $#ARGV < 0);
> ?
> ?if ($color =~ /^[01]$/) {
> ?	$color = !$color;