[Linux-kernel-mentees] [PATCH v3] checkpatch: improve email parsing

[Joe Perches]

(adding stable and Greg KH for additional review)
On Thu, 2020-11-05 at 17:29 +0530, Dwaipayan Ray wrote:
> checkpatch doesn't report warnings for many common mistakes
> in emails. Some of which are trailing commas and incorrect
> use of email comments.

I presume you've tested this against the git tree.

Can you send me a file with the BAD_SIGN_OFF messages generated
and if possible the git SHA-1s of the commits?

> At the same time several false positives are reported due to
> incorrect handling of mail comments. The most common of which
> is due to the pattern:
> 
> <stable at vger.kernel.org> # X.X
> 
> Improve email parsing in checkpatch.
> 
> Some general comment rules are defined:
> 
> - Multiple name comments should not be allowed.
> - Comments inside address should not be allowed.
> - In general comments should be enclosed within parentheses.
>   Exception for stable at vger.kernel.org # X.X

not just vger.kernel.org, but this should also allow stable at kernel.org
and only allow cc: and not any other -by: type for that email address.

A process preference question for Greg and the stable team:

The most common stable forms are

	stable at vger.kernel.org # version info
then
	stable at vger.kernel.org [ version info ]

with some other relatively infrequently used outlier styles, some
that use parentheses, but this is not frequent.

It might be sensible to standardize on the "# version info" trailer
comment version info style and warn on any other form.

A somewhat common style for the stable address is to use a name
before the stable address which describes the version info:

Perhaps any name before stable should be warned and the version
should be a comment.

Here's a list of the stable addresses with "version name" then
stable address in the git tree and other outlier styles.

     24 linux-stable <stable at vger.kernel.org>
     21 5.4+ <stable at vger.kernel.org>
     14 All applicable <stable at vger.kernel.org>
      6 3.10+ <stable at vger.kernel.org>
      5 5.9+ <stable at vger.kernel.org>
      5 5.3+ <stable at vger.kernel.org>
      5 5.1+ <stable at vger.kernel.org>
      4 5.6+ <stable at vger.kernel.org>
      4 4.20+ <stable at vger.kernel.org>
      3 Stable Team <stable at vger.kernel.org>
      3 4.19+ <stable at vger.kernel.org>
      3 4.15+ <stable at vger.kernel.org>
      3 4.10+ <stable at vger.kernel.org>
      2 stable at vger.kernel.org (v2.6.12+)
      2 5.2+ <stable at vger.kernel.org>
      2 4.16+ <stable at vger.kernel.org>
      1 v5.8+ <stable at vger.kernel.org>
      1 v5.7+ <stable at vger.kernel.org>
      1 v5.6+ <stable at vger.kernel.org>
      1 v5.3+ <stable at vger.kernel.org>
      1 v5.0+ <stable at vger.kernel.org>
      1 v4.9+ <stable at vger.kernel.org>
      1 <stable at vger.kernel.org> v5.0+
      1 <stable at vger.kernel.org> +v4.18
      1 stable at vger.kernel.org (3.14+)
      1 5.8+ <stable at vger.kernel.org>
      1 5.5+ <stable at vger.kernel.org>
      1 5.0+ <stable at vger.kernel.org>
      1 4.18+ <stable at vger.kernel.org>
      1 4.14+ <stable at vger.kernel.org>
      1 4.13+ <stable at vger.kernel.org>
      1 4.0+ <stable at vger.kernel.org>
      1 3.15+ <stable at vger.kernel.org>
      1 3.11+ <stable at vger.kernel.org>

> Improvements to parsing:
> 
> - Detect and report unexpected content after email.
> - Quoted names are excluded from comment parsing.
> - Trailing dots or commas in email are removed during
>   formatting. Correspondingly a BAD_SIGN_OFF warning
>   is emitted.
> - Improperly quoted email like '"name <address>"' are now
>   warned about.

All of the above seems right but perhaps the comment style for any
<foo>-by: lines should also allow # comments.

The below is just comments on the patch itself.

> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -2800,9 +2806,57 @@ sub process {
>  				$dequoted =~ s/" </ </;
>  				# Don't force email to have quotes
>  				# Allow just an angle bracketed address
> -				if (!same_email_addresses($email, $suggested_email, 0)) {
> +				if (!same_email_addresses($email, $suggested_email)) {
> +					if (WARN("BAD_SIGN_OFF",
> +					    "email address '$email' might be better as '$suggested_email'\n" . $herecurr) &&
> +						$fix) {

trivia:

Please always align $fix with tabs to the if and then 4 spaces to the
open parenthesis.

> +				# Comments must begin only with (
> +				# or # in case of stable at vger.kernel.org
> +				if ($email =~ /^.*stable\@vger/) {

I believe this should be

				if ($email =~ /^stable\@(?:vger\.)?kernel.org$/) {

> +					if ($comment ne "" && $comment !~ /^#.+/) {
> +						if (WARN("BAD_SIGN_OFF",
> +						    "Invalid comment format for stable: '$email', prefer parentheses\n" . $herecurr) &&

Prefer #

> +							$fix) {
> +							my $new_comment = $comment;
> +							$new_comment =~ s/^[ \(\[]+|[ \)\]]+$//g;

Does the comment include any leading whitespace here?
I presumed not given the $comment !~ /^#/ test above.