Improve parsing of kiwi's derived_from attribute

Build/Kiwi.pm

@@ -144,25 +144,28 @@ sub kiwiparse {
       if ($type->{'derived_from'}) {
 	my $derived = $type->{'derived_from'};
 	my ($name, $prp);
-	if ($derived =~ /^obs:\/{1,3}([^\/]+)\/([^\/]+)\/(.*)(?:#([^\#\/]+))$/) {
-	  $name = defined($4) ? "$3:$4" : "$3";
+	if ($derived =~ /^obs:\/{1,3}([^\/]+)\/([^\/]+)\/(.*?)(?:#([^\#\/]+))?$/) {
+	  $name = defined($4) ? "$3:$4" : "$3:latest";
 	  $prp = "$1/$2";
-	} elsif ($derived =~ /^obsrepositories:\/{1,3}([^\/].*)(?:#([^\#\/]+))$/) {
-	  $name = defined($2) ? "$1:$2" : "$1";
-	} elsif ($derived !~ /^file:/ && $derived =~ /^(.*)\/([^\/]+)(?:#([^\#\/]+))$/) {
+	} elsif ($derived =~ /^obsrepositories:\/{1,3}([^\/].*?)(?:#([^\#\/]+))?$/) {
+	  $name = defined($2) ? "$1:$2" : "$1:latest";
+	} elsif ($derived =~ /^file:/) {
+	  next;		# just ignore and hope
+	} elsif ($derived =~ /^(.*)\/([^\/]+?)(?:#([^\#\/]+))?$/) {
 	  my $url = $1;
-	  $name = defined($3) ? "$2:$3" : "$2";
+	  $name = defined($3) ? "$2:$3" : "$2:latest";
 	  $prp = $urlmapper->($url) if $urlmapper;
 	  # try again with one element moved from url to name
-	  if (!$prp && $derived =~ /^(.*)\/([^\/]+\/[^\/]+)(?:#([^\#\/]+))$/) {
+	  if (!$prp && $derived =~ /^(.*)\/([^\/]+\/[^\/]+?)(?:#([^\#\/]+))?$/) {
 	    $url = $1;
-	    $name = defined($3) ? "$2:$3" : "$2";
+	    $name = defined($3) ? "$2:$3" : "$2:latest";
 	    $prp = $urlmapper->($url) if $urlmapper;
 	  }
-	  die("derived_from url not using obs:/ scheme: $derived\n") unless $prp;
+	  undef $name unless $prp;
 	}
-        push @packages, "container:$name" if defined $name;
-        push @containerrepos, $prp if $prp;
+	die("derived_from url not using obs:/ scheme: $derived\n") unless defined $name;
+	push @packages, "container:$name";
+	push @containerrepos, $prp if $prp;
       }
 
       push @packages, "kiwi-filesystem:$type->{'filesystem'}" if $type->{'filesystem'};