Ruby 1.9.2: StringIO no longer has #path

actionpack/lib/action_dispatch/http/request.rb

@@ -489,7 +489,7 @@ module UploadedFile
         def self.extended(object)
           object.class_eval do
             attr_accessor :original_path, :content_type
-            alias_method :local_path, :path
+            alias_method :local_path, :path if method_defined?(:path)
           end
         end