Re: [PATCH v2] docs: Clarify the usage and sign-off requirements for Co-developed-by

[Joe Perches]

On Thu, 2019-03-21 at 12:23 -0700, Sean Christopherson wrote:
> On Thu, Mar 21, 2019 at 11:43:16AM -0700, Sean Christopherson wrote:
> > The documentation for Co-developed-by is a bit light on details, e.g. it
> > doesn't explicitly state that:
> > 
> >   - Multiple Co-developed-by tags are perfectly acceptable
> >   - Co-developed-by and Signed-off-by must be paired together
> >   - SOB ordering should still follow standard sign-off procedure

While I still think co-developed-by: is unnecessary and
almost none of the existing uses of this have this
sequence of "Co-developed-by: <name/email>" followed directly
by "Signed-off-by: <same name/email>", here's a possible
checkpatch addition for it.

---
 scripts/checkpatch.pl | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index d0001fd1112d..e938fd56cc20 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2687,6 +2687,15 @@ sub process {
 			} else {
 				$signatures{$sig_nospace} = 1;
 			}
+
+# Check Co-developed-by: suceeded by Signed-off-by: with same name and email
+			if ($sign_off =~ /^signed-off-by:$/i &&
+			    $linenr > 1 &&
+			    $rawlines[$linenr - 2] =~ /^\s*co-developed-by:\s*(.*)/i &&
+			    $1 ne $email) {
+				WARN("BAD_SIGN_OFF",
+				     "Co-developed-by: should be suceeded by Signed-off-by: with same name/email\n" . "$here\n" . $rawlines[$linenr - 2] . "\n" . $rawline);
+			}
 		}
 
 # Check email subject for common tools that don't need to be mentioned