Change AV formats so they can delegate to the controller. Now users (or plugins) can override details_for_render in their controllers and add appropriate additional details. Now if only they could *do* something with those details...

actionpack/lib/action_controller/base.rb

@@ -52,7 +52,7 @@ module ActionController
 
       def method_for_action(action_name)
         super || begin
-          if view_paths.exists?(action_name.to_s, {:formats => formats}, controller_path)
+          if view_paths.exists?(action_name.to_s, details_for_render, controller_path)
             "default_render"
           end
         end

actionpack/lib/action_controller/metal/rendering.rb

@@ -23,10 +23,14 @@ module ActionController
 
       def _render_partial(options)
         options[:partial] = action_name if options[:partial] == true
-        options[:_details] = {:formats => formats}
+        options[:_details] = details_for_render
         super
       end
 
+      def details_for_render
+        {:formats => formats}
+      end
+
       def format_for_text
         formats.first
       end

actionpack/lib/action_view/helpers/prototype_helper.rb

@@ -182,14 +182,12 @@ module ActionView
         def initialize(context, &block) #:nodoc:
           context._evaluate_assigns_and_ivars
           @context, @lines = context, []
-          old_formats = @context.formats
-          @context.reset_formats([:js, :html]) if @context
-          include_helpers_from_context
-          @context.with_output_buffer(@lines) do
-            @context.instance_exec(self, &block)
+          @context.reset_formats([:js, :html]) do
+            include_helpers_from_context
+            @context.with_output_buffer(@lines) do
+              @context.instance_exec(self, &block)
+            end
           end
-        ensure
-          @context.reset_formats(old_formats) if @context
         end
 
         private
@@ -573,15 +571,19 @@ module ActionView
               end
             end
 
-            def render(*options_for_render)
-              old_formats = @context && @context.formats
+            def render(*options)
+              with_formats(:html) do
+                case option = options.first
+                when Hash
+                  @context.render(*options)
+                else
+                  option.to_s
+                end
+              end
+            end
 
-              @context.reset_formats([:html]) if @context
-              Hash === options_for_render.first ?
-                @context.render(*options_for_render) :
-                  options_for_render.first.to_s
-            ensure
-              @context.reset_formats(old_formats) if @context
+            def with_formats(*args)
+              @context ? @context.reset_formats(args) { yield } : yield
             end
 
             def javascript_object_for(object)

actionpack/lib/action_view/render/rendering.rb

@@ -25,7 +25,7 @@ module ActionView
         end
 
         template = if options[:file]
-          find(options[:file], {:formats => formats})
+          find(options[:file], details_for_render)
         elsif options[:inline]
           handler = Template.handler_class_for_extension(options[:type] || "erb")
           Template.new(options[:inline], "inline template", handler, {})
@@ -34,7 +34,7 @@ module ActionView
         end
 
         if template
-          layout = find(layout, {:formats => formats}) if layout
+          layout = find(layout, details_for_render) if layout
           _render_template(template, layout, :locals => options[:locals])
         end
       when :update
@@ -44,6 +44,10 @@ module ActionView
       end
     end
 
+    def details_for_render
+      controller.try(:details_for_render) || {:formats => formats}
+    end
+
     # You can think of a layout as a method that is called with a block. _layout_for
     # returns the contents that are yielded to the layout. If the user calls yield
     # :some_name, the block, by default, returns content_for(:some_name). If the user

actionpack/test/template/javascript_helper_test.rb

@@ -9,6 +9,7 @@ class JavaScriptHelperTest < ActionView::TestCase
 
   def reset_formats(format)
     @format = format
+    yield if block_given?
   end
 
   def setup

actionpack/test/template/prototype_helper_test.rb

@@ -41,6 +41,7 @@ class PrototypeHelperBaseTest < ActionView::TestCase
 
   def reset_formats(format)
     @format = format
+    yield if block_given?
   end
 
   def setup