1 files changed, 9 insertions, 0 deletions
diff --git a/actionpack/lib/action_controller/abstract/exceptions.rb b/actionpack/lib/action_controller/abstract/exceptions.rb
index 2f6c55f068..b671516de1 100644
--- a/actionpack/lib/action_controller/abstract/exceptions.rb
+++ b/actionpack/lib/action_controller/abstract/exceptions.rb
@@ -1,3 +1,12 @@
 module AbstractController
+  class Error < StandardError; end
   class ActionNotFound < StandardError; end
+
+  class DoubleRenderError < Error
+    DEFAULT_MESSAGE = "Render and/or redirect were called multiple times in this action. Please note that you may only call render OR redirect, and at most once per action. Also note that neither redirect nor render terminate execution of the action, so if you want to exit an action after redirecting, you need to do something like \"redirect_to(...) and return\"."
+
+    def initialize(message = nil)
+      super(message || DEFAULT_MESSAGE)
+    end
+  end
 end