Re: [PATCH] checkpatch: extend author Signed-off-by check for split From: header

[Joe Perches <joe@perches.com>]

On Sat, 2020-09-19 at 13:42 +0530, Dwaipayan Ray wrote:
> Checkpatch did not handle cases where the author From: header
> was split into two lines. The author string went empty and
> checkpatch generated a false NO_AUTHOR_SIGN_OFF warning.

It's good to provide an example where the current code
doesn't work.

It likely would be better to do this by searching forward for
any extension lines after a "^From:' rather than searching
backwards as there can be any number of extension lines.

> Support split From: headers in AUTHOR_SIGN_OFF check by adding
> an additional clause to resolve author identity in such cases.
> 
> Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com>
> ---
>  scripts/checkpatch.pl | 28 ++++++++++++++++++++++++----
>  1 file changed, 24 insertions(+), 4 deletions(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 504d2e431c60..86975baead22 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -1210,6 +1210,16 @@ sub reformat_email {
>  	return format_email($email_name, $email_address);
>  }
>  
> +sub format_author_email {
> +	my ($email, $from) = @_;
> +
> +	$email = encode("utf8", $email) if ($from =~ /=\?utf-8\?/i);
> +	$email =~ s/"//g;
> +	$email = reformat_email($email);
> +
> +	return $email;
> +}
> +
>  sub same_email_addresses {
>  	my ($email1, $email2) = @_;
>  
> @@ -2347,6 +2357,7 @@ sub process {
>  	my $signoff = 0;
>  	my $author = '';
>  	my $authorsignoff = 0;
> +	my $prevheader = '';
>  	my $is_patch = 0;
>  	my $is_binding_patch = -1;
>  	my $in_header_lines = $file ? 0 : 1;
> @@ -2658,12 +2669,21 @@ sub process {
>  			}
>  		}
>  
> +# Check the patch for a split From:
> +		if($prevheader ne '') {
> +			if ($author eq '' && decode("MIME-Header", $prevheader) =~ /^From:\s*(.*)/) {
> +				my $email = $1.$line;
> +				$author = format_author_email($email, $prevheader);
> +			}
> +			$prevheader = '';
> +		}
> +
>  # Check the patch for a From:
>  		if (decode("MIME-Header", $line) =~ /^From:\s*(.*)/) {
> -			$author = $1;
> -			$author = encode("utf8", $author) if ($line =~ /=\?utf-8\?/i);
> -			$author =~ s/"//g;
> -			$author = reformat_email($author);
> +			$author = format_author_email($1, $line);
> +			if($author eq '') {
> +				$prevheader = $line;
> +			}
>  		}
>  
>  # Check the patch for a signoff: