[PATCH] checkpatch: Require author Signed-off-by

[Geert Uytterhoeven]

Print an error if none of the Signed-off-by lines cover the patch
author.

Non-ASCII quoted printable encoding in From: headers and (lack of)
double quotes are handled.
Split From: headers are not fully handled: only the first part is
compared.

Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
Tested using a set of ca. 4000 real world commits.

Most common offenders are people using:
  - different email addresses for author and Sob,
  - different firstname/lastname order, or other different name
    spelling,
  - suse.de vs. suse.com.
---
 scripts/checkpatch.pl | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 8d0bad190c25e2e0..53f3dcf9171447f4 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -13,6 +13,7 @@ use POSIX;
 use File::Basename;
 use Cwd 'abs_path';
 use Term::ANSIColor qw(:constants);
+use MIME::Words 'decode_mimewords';
 
 my $P = $0;
 my $D = dirname(abs_path($P));
@@ -2236,6 +2237,8 @@ sub process {
 
 	our $clean = 1;
 	my $signoff = 0;
+	my $author = '';
+	my $authorsignoff = 0;
 	my $is_patch = 0;
 	my $in_header_lines = $file ? 0 : 1;
 	my $in_commit_log = 0;		#Scanning lines before patch
@@ -2518,10 +2521,23 @@ sub process {
 			}
 		}
 
+# Check the patch for a From:
+		if ($line =~ /^\s*From: (.*)/i) {
+			$author = decode_mimewords($1);
+			$author =~ s/"//g;
+		}
+
 # Check the patch for a signoff:
 		if ($line =~ /^\s*signed-off-by:/i) {
 			$signoff++;
 			$in_commit_log = 0;
+			if ($author ne '') {
+				my $l = $line;
+				$l =~ s/"//g;
+				if ($l =~ /^\s*signed-off-by: \Q$author\E/i) {
+				    $authorsignoff = 1;
+				}
+			}
 		}
 
 # Check if MAINTAINERS is being updated.  If so, there's probably no need to
@@ -6487,9 +6503,14 @@ sub process {
 		ERROR("NOT_UNIFIED_DIFF",
 		      "Does not appear to be a unified-diff format patch\n");
 	}
-	if ($is_patch && $has_commit_log && $chk_signoff && $signoff == 0) {
-		ERROR("MISSING_SIGN_OFF",
-		      "Missing Signed-off-by: line(s)\n");
+	if ($is_patch && $has_commit_log && $chk_signoff) {
+		if ($signoff == 0) {
+			ERROR("MISSING_SIGN_OFF",
+			      "Missing Signed-off-by: line(s)\n");
+		} elsif (!$authorsignoff) {
+			ERROR("NO_AUTHOR_SIGN_OFF",
+			      "Missing Signed-off-by: line by patch author\n");
+		}
 	}
 
 	print report_dump();
-- 
2.17.1