only expand resources when strictly needed

Author: deads2k

pkg/authorization/api/helpers.go

@@ -14,6 +14,20 @@ import (
 )
 
 func ExpandResources(rawResources sets.String) sets.String {
+	// we only need to expand groups if the exist and we don't create them with groups
+	// by default.  Only accept the cost of expansion if we're doing work.
+	needsExpansion := false
+	for rawResource := range rawResources {
+		if strings.Index(currResource, ResourceGroupPrefix+":") == 0 {
+			needsExpansion = true
+			break
+		}
+
+	}
+	if !needsExpansion {
+		return rawResources
+	}
+
 	ret := sets.String{}
 	toVisit := rawResources.List()
 	visited := sets.String{}