linux-kernel - Re: [PATCH] scripts/checkpatch.pl: Improve guidance for LONG

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Thu, 26 Jun 2014 03:09:05 -0700
From:	Joe Perches <joe@...ches.com>
To:	Josh Triplett <josh@...htriplett.org>
Cc:	Andy Whitcroft <apw@...onical.com>, gregkh@...ux-foundation.org,
	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] scripts/checkpatch.pl: Improve guidance for LONG_LINE

On Wed, 2014-06-25 at 23:01 -0700, Josh Triplett wrote:
> Currently, LONG_LINE just informs the user about the line length,
> leaving them to shorten the line.  Too many users run checkpatch and
> blindly follow its recommendation by splitting long lines, which almost
> invariably results in worse code.  On rare occasions, the line-width
> limit encourages sensible refactoring of nested code into functions, but
> more frequently it just results in painfully over-wrapped code.
> 
> Improve the guidance by detecting long lines that start with 4+ tabs and
> explicitly suggesting simplification or refactoring in that case.
[]
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -2146,8 +2146,16 @@ sub process {
>  		    $line =~ /^\+\s*"[^"]*"\s*(?:\s*|,|\)\s*;)\s*$/) &&
>  		    $length > $max_line_length)
>  		{
> -			WARN("LONG_LINE",
> -			     "line over $max_line_length characters\n" . $herecurr);
> +			if ($line =~ /^\+\t{4,}/) {
> +				WARN("LONG_LINE_DEEP_NESTING",
> +				     "line over $max_line_length characters with excessive nesting (4+ tabs)\n"
> +				     . "Consider simplifying or refactoring to eliminate excessive nesting.\n"
> +				     . $herecurr);

This is not the test you want.

This is also emitting on lines that are
merely continued like
			pr_warning(format,
				   arg1,
				   arg2,
				   arg3
				   ...
				   argN);

Better would be to test only for the lines
that increase indents (like the DEEP_INDENTATION test)

$line =~ /^\+\t{4,}(?:if|for|while|do|switch)\b/

This is the treewide distribution I get for the lines
that generally produce extra indentation:

 608432 1
 242180 2
  71260 3
  16953 4
   3688 5
    758 6
    187 7
     74 8
     23 9
     17 10
      8 11
      4 12
      1 13


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/