Re: [Qemu-devel] [PATCH 3/5] CODING_STYLE, checkpatch: update line length rules

[Thomas Huth <thuth@redhat.com>]

On 10.08.2016 10:22, Paolo Bonzini wrote:
> Line lengths above 80 characters do exist.  They are rare, but
> they happen from time to time.  An ignored rule is worse than an
> exception to the rule, so do the latter.
> 
> Some on the list expressed their preference for a soft limit that
> is slightly lower than 80 characters, to account for extra characters
> in unified diffs (including three-way diffs) and for email quoting.
> However, there was no consensus on this so keep the 80-character
> soft limit and add a hard limit at 90.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  CODING_STYLE          | 13 ++++++++++---
>  scripts/checkpatch.pl |  8 ++++++--
>  2 files changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/CODING_STYLE b/CODING_STYLE
> index 3c6978f..4e48a96 100644
> --- a/CODING_STYLE
> +++ b/CODING_STYLE
> @@ -31,14 +31,20 @@ Do not leave whitespace dangling off the ends of lines.
>  
>  2. Line width
>  
> -Lines are 80 characters; not longer.
> +Lines should be 80 characters; try not to make them longer.
> +
> +Sometimes it is hard to do, especially when dealing with QEMU subsystems
> +that use long function or symbol names.  Even in that case, do not make
> +lines much longer than 80 characters.
>  
>  Rationale:
>   - Some people like to tile their 24" screens with a 6x4 matrix of 80x24
>     xterms and use vi in all of them.  The best way to punish them is to
>     let them keep doing it.
>   - Code and especially patches is much more readable if limited to a sane
>     line length.  Eighty is traditional.
> + - The four-space indentation makes the most common excuse ("But look
> +   at all that white space on the left!") moot.
>   - It is the QEMU coding style.
>  
>  3. Naming
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index f6928db..714a000 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -1336,12 +1336,16 @@ sub process {
>  # check we are in a valid source file if not then ignore this hunk
>  		next if ($realfile !~ /\.(h|c|cpp|s|S|pl|py|sh)$/);
>  
> -#80 column limit
> +#90 column limit
>  		if ($line =~ /^\+/ &&
>  		    !($line =~ /^\+\s*"[^"]*"\s*(?:\s*|,|\)\s*;)\s*$/) &&
>  		    $length > 80)
>  		{
> -			WARN("line over 80 characters\n" . $herecurr);
> +			if ($length > 90) {
> +				ERROR("line over 90 characters\n" . $herecurr);
> +			} else {
> +				WARN("line over 80 characters\n" . $herecurr);
> +			}
>  		}
>  
>  # check for spaces before a quoted newline
> 

Reviewed-by: Thomas Huth <thuth@redhat.com>