Don't run the action if callbacks are halted.

  In AbstractController, this means that response_body is not empty

actionpack/lib/action_controller/abstract/callbacks.rb

@@ -2,7 +2,7 @@ module AbstractController
   module Callbacks
     setup do
       include ActiveSupport::NewCallbacks
-      define_callbacks :process_action      
+      define_callbacks :process_action, "response_body"
     end
 
     def process_action

activesupport/lib/active_support/new_callbacks.rb

@@ -316,7 +316,7 @@ def compile(key = nil, options = {})
         each do |callback|
           method << callback.start(key, options)
         end
-        method << "yield self if block_given?"
+        method << "yield self if block_given? && !halted"
         reverse_each do |callback|
           method << callback.end(key, options)
         end

activesupport/test/new_callbacks_test.rb

@@ -365,7 +365,7 @@ class CallbackTerminator
     save_callback :after, :third
 
 
-    attr_reader :history
+    attr_reader :history, :saved
     def initialize
       @history = []
     end
@@ -390,7 +390,9 @@ def third
     end
 
     def save
-      _run_save_callbacks
+      _run_save_callbacks do
+        @saved = true
+      end
     end
   end
 
@@ -400,13 +402,19 @@ def test_termination
       terminator.save
       assert_equal ["first", "second", "third", "second", "first"], terminator.history
     end
+
+    def test_block_never_called_if_terminated
+      obj = CallbackTerminator.new
+      obj.save
+      assert !obj.saved
+    end    
   end
 
   class HyphenatedKeyTest < Test::Unit::TestCase
     def test_save
       obj = HyphenatedCallbacks.new
       obj.save
       assert_equal obj.stuff, "OMG"
-    end
+    end    
   end  
 end