Ruby 1.9.2: avoid Array#to_s and Array(nil)

activesupport/lib/active_support/vendor/i18n-0.1.3/lib/i18n.rb

@@ -195,10 +195,19 @@ def default_exception_handler(exception, locale, key, options)
     # Merges the given locale, key and scope into a single array of keys.
     # Splits keys that contain dots into multiple keys. Makes sure all
     # keys are Symbols.
-    def normalize_translation_keys(locale, key, scope)
-      keys = [locale] + Array(scope) + [key]
-      keys = keys.map { |k| k.to_s.split(/\./) }
-      keys.flatten.map { |k| k.to_sym }
+    def normalize_translation_keys(*keys)
+      normalized = []
+      keys.each do |key|
+        case key
+        when Array
+          normalized.concat normalize_translation_keys(*key)
+        when nil
+          # skip
+        else
+          normalized.concat key.to_s.split('.').map { |sub| sub.to_sym }
+        end
+      end
+      normalized
     end
   end
 end