Cache JavaScriptGenerator's helper module set on the template

actionpack/lib/action_view/base.rb

@@ -328,11 +328,6 @@ module ActionView #:nodoc:
     memoize :pick_template
 
     private
-      def extended_by_without_helpers #:nodoc:
-        extended_by.reject { |mod| mod.name =~ /^ActionView::Helpers/ }
-      end
-      memoize :extended_by_without_helpers
-
       # Evaluate the local assigns and pushes them to the view.
       def evaluate_assigns
         unless @assigns_added

actionpack/lib/action_view/helpers/prototype_helper.rb

@@ -588,8 +588,26 @@ module ActionView
 
         private
           def include_helpers_from_context
-            @context.send(:extended_by_without_helpers).each { |mod| extend mod }
-            extend GeneratorMethods
+            unless generator_methods_module = @context.instance_variable_get(:@__javascript_generator_methods__)
+              modules = @context.extended_by - ([ActionView::Helpers] + ActionView::Helpers.included_modules)
+
+              generator_methods_module = Module.new do
+                modules.each do |mod|
+                  begin
+                    include mod
+                  rescue Exception => e
+                    # HACK: Probably not a good idea to suppress these warnings
+                    # AFAIK exceptions are only raised in while testing with mocha
+                    # because the module does not like to be included into other
+                    # non TestUnit classes
+                  end
+                end
+                include GeneratorMethods
+              end
+              @context.instance_variable_set(:@__javascript_generator_methods__, generator_methods_module)
+            end
+
+            extend generator_methods_module
           end
 
         # JavaScriptGenerator generates blocks of JavaScript code that allow you

actionpack/test/template/javascript_helper_test.rb

@@ -108,9 +108,4 @@ class JavaScriptHelperTest < ActionView::TestCase
   def test_javascript_cdata_section
     assert_dom_equal "\n//<![CDATA[\nalert('hello')\n//]]>\n", javascript_cdata_section("alert('hello')")
   end
-
-  private
-    def extended_by_without_helpers
-      []
-    end
 end

actionpack/test/template/prototype_helper_test.rb

@@ -53,10 +53,6 @@ class PrototypeHelperBaseTest < ActionView::TestCase
       false
     end
 
-    def extended_by_without_helpers
-      []
-    end
-
     def create_generator
       block = Proc.new { |*args| yield *args if block_given? }
       JavaScriptGenerator.new self, &block