Stack @output_buffer for nested rendering

actionpack/lib/action_view/template_handlers/compilable.rb

@@ -106,7 +106,7 @@ def create_template_source(template, render_symbol)
           locals_code << "#{key} = local_assigns[:#{key}]\n"
         end
 
-        "def #{render_symbol}(local_assigns)\n#{locals_code}#{body}\nend"
+        "def #{render_symbol}(local_assigns)\nold_output_buffer = @output_buffer;#{locals_code}#{body}\nensure\n@output_buffer = old_output_buffer\nend"
       end
 
       # Return true if the given template was compiled for a superset of the keys in local_assigns
@@ -125,4 +125,4 @@ def template_changed_since?(file_name, compile_time)
 
     end
   end
-end
\ No newline at end of file
+end

actionpack/test/controller/caching_test.rb

@@ -512,7 +512,7 @@ def test_fragment_for
 
   def test_cache_erb_fragment
     @store.write('views/expensive', 'fragment content')
-    @controller.template.output_buffer = 'generated till now -> '
+    @controller.response.template.output_buffer = 'generated till now -> '
 
     assert_equal( 'generated till now -> fragment content',
                   ActionView::TemplateHandlers::ERB.new(@controller).cache_fragment(Proc.new{ }, 'expensive'))