Allow root to be given in the resources scope without need to specify :on => collection.

actionpack/lib/action_dispatch/routing/mapper.rb

@@ -693,6 +693,11 @@ module ActionDispatch
           super
         end
 
+        def root(options={})
+          options[:on] ||= :collection if @scope[:scope_level] == :resources
+          super(options)
+        end
+
         protected
           def parent_resource #:nodoc:
             @scope[:scope_level_resource]

actionpack/test/dispatch/routing_test.rb

@@ -186,6 +186,8 @@ class TestRoutingMapper < ActionDispatch::IntegrationTest
       end
 
       resources :products, :constraints => { :id => /\d{4}/ } do
+        root :to => "products#root"
+        get :favorite, :on => :collection
         resources :images
       end
 
@@ -963,7 +965,9 @@ class TestRoutingMapper < ActionDispatch::IntegrationTest
       get '/products/1'
       assert_equal 'pass', @response.headers['X-Cascade']
       get '/products'
-      assert_equal 'products#index', @response.body
+      assert_equal 'products#root', @response.body
+      get '/products/favorite'
+      assert_equal 'products#favorite', @response.body
       get '/products/0001'
       assert_equal 'products#show', @response.body
 
@@ -981,6 +985,12 @@ class TestRoutingMapper < ActionDispatch::IntegrationTest
     end
   end
 
+  def test_root_works_in_the_resources_scope
+    get '/products'
+    assert_equal 'products#root', @response.body
+    assert_equal '/products', products_root_path
+  end
+
   def test_module_scope
     with_test_routes do
       get '/token'