Don't shadow query string method

actionpack/lib/action_controller/rack_process.rb

@@ -25,7 +25,7 @@ def initialize(env, session_options = DEFAULT_SESSION_OPTIONS)
     end
 
     %w[ AUTH_TYPE GATEWAY_INTERFACE PATH_INFO
-        PATH_TRANSLATED QUERY_STRING REMOTE_HOST
+        PATH_TRANSLATED REMOTE_HOST
         REMOTE_IDENT REMOTE_USER SCRIPT_NAME
         SERVER_NAME SERVER_PROTOCOL
 
@@ -37,6 +37,15 @@ def initialize(env, session_options = DEFAULT_SESSION_OPTIONS)
       end
     end
 
+    def query_string
+      qs = super
+      if !qs.blank?
+        qs
+      else
+        @env['QUERY_STRING']
+      end
+    end
+
     def body_stream #:nodoc:
       @env['rack.input']
     end