scripts/get_maintainer.pl: add signatures from Fixes: <badcommit> lines in commit message

A Fixes: lines in a commit message generally indicate that a previous
commit was inadequate for whatever reason.

The signers of the previous inadequate commit should also be cc'd on
this new commit so update get_maintainer to find the old commit and add
the original signers.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Joe Perches <[e-mail]>
Suggested-by: Dan Carpenter <[e-mail]>
Reviewed-by: Kees Cook <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

scripts/get_maintainer.pl

···
 my $email_usename = 1;
 my $email_maintainer = 1;
 my $email_reviewer = 1;
+my $email_fixes = 1;
 my $email_list = 1;
 my $email_moderated_list = 1;
 my $email_subscriber_list = 0;
···
 		'r!' => \$email_reviewer,
 		'n!' => \$email_usename,
 		'l!' => \$email_list,
+		'fixes!' => \$email_fixes,
 		'moderated!' => \$email_moderated_list,
 		's!' => \$email_subscriber_list,
 		'multiline!' => \$output_multiline,
···
 ## use the filenames on the command line or find the filenames in the patchfiles
 
 my @files = ();
+my @fixes = ();			# If a patch description includes Fixes: lines
 my @range = ();
 my @keyword_tvi = ();
 my @file_emails = ();
···
 		my $filename2 = $2;
 		push(@files, $filename1);
 		push(@files, $filename2);
+	    } elsif (m/^Fixes:\s+([0-9a-fA-F]{6,40})/) {
+		push(@fixes, $1) if ($email_fixes);
 	    } elsif (m/^\+\+\+\s+(\S+)/ or m/^---\s+(\S+)/) {
 		my $filename = $1;
 		$filename =~ s@^[^/]*/@@;
···
 }
 
 @file_emails = uniq(@file_emails);
+@fixes = uniq(@fixes);
 
 my %email_hash_name;
 my %email_hash_address;
···
 my %deduplicate_address_hash = ();
 
 my @maintainers = get_maintainers();
-
 if (@maintainers) {
     @maintainers = merge_email(@maintainers);
     output(@maintainers);
···
 	}
     }
 
+    foreach my $fix (@fixes) {
+	vcs_add_commit_signers($fix, "blamed_fixes");
+    }
+
     foreach my $email (@email_to, @list_to) {
 	$email->[0] = deduplicate_email($email->[0]);
     }
···
     --roles => show roles (status:subsystem, git-signer, list, etc...)
     --rolestats => show roles and statistics (commits/total_commits, %)
     --file-emails => add email addresses found in -f file (default: 0 (off))
+    --fixes => for patches, add signatures of commits with 'Fixes: <commit>' (default: 1 (on))
   --scm => print SCM tree(s) if any
   --status => print status if any
   --subsystem => print subsystem name if any
···
 
 sub vcs_is_hg {
     return $vcs_used == 2;
+}
+
+sub vcs_add_commit_signers {
+    return if (!vcs_exists());
+
+    my ($commit, $desc) = @_;
+    my $commit_count = 0;
+    my $commit_authors_ref;
+    my $commit_signers_ref;
+    my $stats_ref;
+    my @commit_authors = ();
+    my @commit_signers = ();
+    my $cmd;
+
+    $cmd = $VCS_cmds{"find_commit_signers_cmd"};
+    $cmd =~ s/(\$\w+)/$1/eeg;	#substitute variables in $cmd
+
+    ($commit_count, $commit_signers_ref, $commit_authors_ref, $stats_ref) = vcs_find_signers($cmd, "");
+    @commit_authors = @{$commit_authors_ref} if defined $commit_authors_ref;
+    @commit_signers = @{$commit_signers_ref} if defined $commit_signers_ref;
+
+    foreach my $signer (@commit_signers) {
+	$signer = deduplicate_email($signer);
+    }
+
+    vcs_assign($desc, 1, @commit_signers);
 }
 
 sub interactive_get_maintainers {