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

[Lukas Bulwahn]

On Sat, 19 Sep 2020, Joe Perches wrote:

> On Sat, 2020-09-19 at 20:12 +0200, Lukas Bulwahn wrote:
> > 
> > On Sat, 19 Sep 2020, Joe Perches wrote:
> > 
> > > 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.
> > > 
> > 
> > Joe, as this is a linux-kernel-mentees patch, we discussed that before 
> > reaching out to you; you can find Dwaipayan's own evaluation here:
> > 
> > https://lore.kernel.org/linux-kernel-mentees/CABJPP5BOTG0QLFSaRJTb2vAZ_hJf229OAQihHKG4sYd35i_WMw@xxxxxxxxxxxxxx/
> > 
> > Dwaipayan, Joe's comment is still valid; it would be good to describe
> > the reasons why patches might have split lines (as far as see, long 
> > encodings for non-ascii names).
> > 
> > I will run my own evaluation of checkpatch.pl before and after patch 
> > application on Monday and then check if I can confirm Dwaipayan's results.
> > 
> > > 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.
> > > 
> > 
> > Just to sure what you are talking about...
> > 
> > You mean just to access the next line through the lines array, rather 
> > than using prevheader and trying to decode that one line twice.
> > 
> > I agree the logic is a bit redundant and complicated at the moment.
> > 
> > Once prevheader is non-empty, it already clear that author is '' and 
> > prevheader decodes with that match, because that is the only way to
> > make prevheader non-empty in the first place; at least as far I see it 
> > right now.
> 
> Yeah, something like this (completely untested):
> ---
>  scripts/checkpatch.pl | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 3e474072aa90..2c710d05b184 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -2679,9 +2679,13 @@ sub process {
>  		}
>  
>  # Check the patch for a From:
> -		if (decode("MIME-Header", $line) =~ /^From:\s*(.*)/) {
> +		if ($line =~ /^From:\s*(.*)/i) {
>  			$author = $1;
> -			$author = encode("utf8", $author) if ($line =~ /=\?utf-8\?/i);
> +			my $curline = $linenr;
> +			while (defined($rawlines[$curline] && $rawlines[$curline++] =~ /^ \s*(.*)/) {
> +				$author .= $1;
> +			}
> +			$author = encode("utf8", $author) if ($author =~ /=\?utf-8\?/i);
>  			$author =~ s/"//g;
>  			$author = reformat_email($author);
>  		}
>

Yeah, I get how you would like to see that being implemented. I will work 
with Dwaipayan to get that properly implemented, properly described and 
tested.

But let us keep the fun of that task to Dwaipayan... that is what a 
mentorship is all about :)

Lukas