Always downstream given options in :json, :xml and :js renderers and add tests for it.

actionpack/lib/action_controller/metal/renderers.rb

@@ -79,12 +79,12 @@ module ActionController
 
     add :js do |js, options|
       self.content_type ||= Mime::JS
-      self.response_body  = js.respond_to?(:to_js) ? js.to_js : js
+      self.response_body  = js.respond_to?(:to_js) ? js.to_js(options) : js
     end
 
     add :xml do |xml, options|
       self.content_type ||= Mime::XML
-      self.response_body  = xml.respond_to?(:to_xml) ? xml.to_xml : xml
+      self.response_body  = xml.respond_to?(:to_xml) ? xml.to_xml(options) : xml
     end
 
     add :update do |proc, options|

actionpack/test/controller/render_json_test.rb

@@ -3,6 +3,14 @@ require 'controller/fake_models'
 require 'pathname'
 
 class RenderJsonTest < ActionController::TestCase
+  class JsonRenderable
+    def as_json(options={})
+      hash = { :a => :b, :c => :d, :e => :f }
+      hash.except!(*options[:except]) if options[:except]
+      hash
+    end
+  end
+
   class TestController < ActionController::Base
     protect_from_forgery
 
@@ -37,6 +45,10 @@ class RenderJsonTest < ActionController::TestCase
     def render_json_with_render_to_string
       render :json => {:hello => render_to_string(:partial => 'partial')}
     end
+
+    def render_json_with_extra_options
+      render :json => JsonRenderable.new, :except => [:c, :e]
+    end
   end
 
   tests TestController
@@ -91,4 +103,10 @@ class RenderJsonTest < ActionController::TestCase
     assert_equal '{"hello":"partial html"}', @response.body
     assert_equal 'application/json', @response.content_type
   end
+
+  def test_render_json_forwards_extra_options
+    get :render_json_with_extra_options
+    assert_equal '{"a":"b"}', @response.body
+    assert_equal 'application/json', @response.content_type
+  end
 end

actionpack/test/controller/render_xml_test.rb

@@ -3,6 +3,13 @@ require 'controller/fake_models'
 require 'pathname'
 
 class RenderXmlTest < ActionController::TestCase
+  class XmlRenderable
+    def to_xml(options)
+      options[:root] ||= "i-am-xml"
+      "<#{options[:root]}/>"
+    end
+  end
+
   class TestController < ActionController::Base
     protect_from_forgery
 
@@ -20,13 +27,7 @@ class RenderXmlTest < ActionController::TestCase
     end
 
     def render_with_to_xml
-      to_xmlable = Class.new do
-        def to_xml
-          "<i-am-xml/>"
-        end
-      end.new
-
-      render :xml => to_xmlable
+      render :xml => XmlRenderable.new
     end
 
     def formatted_xml_erb
@@ -35,6 +36,10 @@ class RenderXmlTest < ActionController::TestCase
     def render_xml_with_custom_content_type
       render :xml => "<blah/>", :content_type => "application/atomsvc+xml"
     end
+
+    def render_xml_with_custom_options
+      render :xml => XmlRenderable.new, :root => "i-am-THE-xml"
+    end
   end
 
   tests TestController
@@ -58,6 +63,11 @@ class RenderXmlTest < ActionController::TestCase
     assert_equal "<i-am-xml/>", @response.body
   end
 
+  def test_rendering_xml_should_call_to_xml_with_extra_options
+    get :render_with_to_xml
+    assert_equal "<i-am-xml/>", @response.body
+  end
+
   def test_rendering_with_object_location_should_set_header_with_url_for
     with_routing do |set|
       set.draw do |map|