get_maintainer.pl: Teach brace expansion

Simpler non-nested brace expansion.

Some entries in the MAINTAINER are not understood by the script, the
ones that contain {,}. This patch fixes it.

This will convert brace expansion style use in MAINTAINER into a regex
that get_maintainer.pl can use to match a path again a maintainer
section.

It is done by using two different regex, the first one will take care of
converting ',' inside '{}' to a '|', one by one, as long as there is at
least two commas. The second regex will do the final convertion of '{,}'
to '(|)'.

With the patch, the right maintainers are displayed, instead of "THE
REST" maintainers, when using the following command for e.g.
$ ./scripts/get_maintainer.pl -f docs/misc/kconfig.txt

The patch also get rid of the warnings, with recent perl:
Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/^docs/misc/kconfig{ <-- HERE ,-language}\.txt/ at ./scripts/get_maintainer.pl line 731.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Tested-by: Doug Goldstein <cardoe@cardoe.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

scripts/get_maintainer.pl

@@ -283,6 +283,13 @@ while (<$maint>) {
 
 	##Filename pattern matching
 	if ($type eq "F" || $type eq "X") {
+	    # Bash brace expansion, not nested
+	    # match {,*,*} and transform ',' to '|' one by one.
+	    # While there is more than one ',', convert one to '|'.
+	    while ($value =~ s/([^\\])\{(|[^},]*[^,\\]),((|[^},]*[^,\\]),(|[^}]*[^\\]))\}/$1\{$2|$3\}/g) {
+	    }
+	    $value =~ s/([^\\])\{(|[^},]*[^,\\]),(|[^}]*[^\\])\}/$1($2|$3)/g;
+
 	    $value =~ s@\.@\\\.@g;       ##Convert . to \.
 	    $value =~ s/\*/\.\*/g;       ##Convert * to .*
 	    $value =~ s/\?/\./g;         ##Convert ? to .
@@ -637,6 +644,12 @@ sub get_maintainers {
 			$line =~ s/([^\\])\.$/$1\?/g;	##Convert . back to ?
 			$line =~ s/\\\./\./g;       	##Convert \. to .
 			$line =~ s/\.\*/\*/g;       	##Convert .* to *
+			## Convert (|) back to {,}
+			# match (|*|*) and transform '|' to ',' one by one
+			# While there is more than one '|', convert one to ','.
+			while ($line =~ s/([^\\])\((|[^)|]*[^|\\])\|((|[^)|]*[^|\\])\|(|[^)]*[^\\]))\)/$1($2,$3)/g) {
+			}
+			$line =~ s/([^\\])\((|[^)|]*[^|\\])\|(|[^)]*[^\\])\)/$1\{$2,$3\}/g;
 		    }
 		    $line =~ s/^([A-Z]):/$1:\t/g;
 		    print("$line\n");