Re: [PATCH 1/1] checkpatch: check for subject uniqueness in git repository.

[Joe Perches <joe@perches.com>]

On Mon, 2014-09-15 at 20:43 +0200, Fabian Frederick wrote:
> Adding patch subject uniqueness check in checkpatch --strict mode.
> See Documentation/SubmittingPatches/globally-unique identifier.

Perhaps something like this?
---
 scripts/checkpatch.pl | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 0c520f7..e19c40b 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -622,6 +622,27 @@ sub git_commit_info {
 	return ($id, $desc);
 }
 
+my @git_commits = ();
+my @previous_subjects = ();
+
+sub check_subject_duplication {
+	my ($subject) = @_;
+
+	if ($check && $#git_commits < 1 && which("git") && -e ".git") {
+		my $output = `git log --no-color --format='%H %s' 2>&1`;
+		$output =~ s/^\s*//gm;
+		@git_commits = split("\n", $output);
+	}
+
+	return 1 if (grep(/^[a-f0-9]{40,40} $subject$/, @git_commits));
+
+	return 2 if (grep(/^$subject$/, @previous_subjects));
+
+	push(@previous_subjects, $subject);
+
+	return 0;
+}
+
 $chk_signoff = 0 if ($file);
 
 my @rawlines = ();
@@ -1264,6 +1285,20 @@ sub raw_line {
 	return $line;
 }
 
+sub get_complete_header {
+	my ($linenr) = @_;
+
+	my $offset = $linenr - 1;
+
+	my $line = $rawlines[$offset++];
+	while (defined $rawlines[$offset] &&
+	       $rawlines[$offset] =~ /\s(\S.*)$/) {
+		$line .= $rawlines[$offset++];
+	}
+
+	return $line;
+}
+
 sub cat_vet {
 	my ($vet) = @_;
 	my ($res, $coded);
@@ -2047,6 +2082,23 @@ sub process {
 			}
 		}
 
+# Check git commit and patch subject duplication
+		if ($in_header_lines && $line =~ /^Subject:/) {
+			my $subject = get_complete_header($linenr);
+			if ($subject =~ /^Subject:\s*(?:\[[^\]]*\])?\s*(.*)$/) {
+				$subject = $1;
+			}
+
+			my $subject_dup = check_subject_duplication($subject);
+			if ($subject_dup == 1) {
+				CHK("NOT_UNIQUE_SUBJECT",
+				    "Identical git commit subject found\n" . $herecurr);
+			} elsif ($subject_dup == 2) {
+				CHK("NOT_UNIQUE_SUBJECT",
+				    "Identical patch commit subject found\n" . $herecurr);
+			}
+		}
+
 # Check the patch for a signoff:
 		if ($line =~ /^\s*signed-off-by:/i) {
 			$signoff++;