[PATCH] checkpatch: Additional MAINTAINER section entry ordering checks

[Joe Perches]

There is a preferred order for the entries in MAINTAINERS sections.

See:

commit 3b50142d8528 ("MAINTAINERS: sort field names for all entries")
and
commit 6680125ea5a2 ("MAINTAINERS: list the section entries in the preferred order)

Add checkpatch tests to try to keep that ordering.

Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
---
 scripts/checkpatch.pl | 45 +++++++++++++++++++++++++++++++++++++--------
 1 file changed, 37 insertions(+), 8 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index d64c67..3c44833 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3060,14 +3060,43 @@ sub process {
 			#print "is_start<$is_start> is_end<$is_end> length<$length>\n";
 		}
 
-# check for MAINTAINERS entries that don't have the right form
-		if ($realfile =~ /^MAINTAINERS$/ &&
-		    $rawline =~ /^\+[A-Z]:/ &&
-		    $rawline !~ /^\+[A-Z]:\t\S/) {
-			if (WARN("MAINTAINERS_STYLE",
-				 "MAINTAINERS entries use one tab after TYPE:\n" . $herecurr) &&
-			    $fix) {
-				$fixed[$fixlinenr] =~ s/^(\+[A-Z]):\s*/$1:\t/;
+# check MAINTAINERS entries
+		if ($realfile =~ /^MAINTAINERS$/) {
+# check MAINTAINERS entries for the right form
+			if ($rawline =~ /^\+[A-Z]:/ &&
+			    $rawline !~ /^\+[A-Z]:\t\S/) {
+				if (WARN("MAINTAINERS_STYLE",
+					 "MAINTAINERS entries use one tab after TYPE:\n" . $herecurr) &&
+				    $fix) {
+					$fixed[$fixlinenr] =~ s/^(\+[A-Z]):\s*/$1:\t/;
+				}
+			}
+# check MAINTAINERS entries for the right ordering too
+			my $preferred_order = 'MRLSWQBCPTFXNK';
+			if ($rawline =~ /^\+[A-Z]:/ &&
+			    $prevrawline =~ /^[\+ ][A-Z]:/) {
+				$rawline =~ /^\+([A-Z]):\s*(.*)/;
+				my $cur = $1;
+				my $curval = $2;
+				$prevrawline =~ /^[\+ ]([A-Z]):\s*(.*)/;
+				my $prev = $1;
+				my $prevval = $2;
+				my $curindex = index($preferred_order, $cur);
+				my $previndex = index($preferred_order, $prev);
+				if ($curindex < 0) {
+					WARN("MAINTAINERS_STYLE",
+					     "Unknown MAINTAINERS entry type: '$cur'\n" . $herecurr);
+				} else {
+					if ($previndex >= 0 && $curindex < $previndex) {
+						WARN("MAINTAINERS_STYLE",
+						     "Misordered MAINTAINERS entry - list '$cur:' before '$prev:'\n" . $hereprev);
+					} elsif ((($prev eq 'F' && $cur eq 'F') ||
+						  ($prev eq 'X' && $cur eq 'X')) &&
+						 ($prevval cmp $curval) > 0) {
+						WARN("MAINTAINERS_STYLE",
+						     "Misordered MAINTAINERS entry - list file patterns in alphabetic order\n" . $hereprev);
+					}
+				}
 			}
 		}