Fix render :file => "#{Rails.root}/public/404.html", :status => :not_found. Closes #8994

actionpack/lib/action_view/template/resolver.rb

@@ -20,7 +20,7 @@ module ActionView
 
     register_detail(:locale)  { [I18n.locale] }
     register_detail(:formats) { Mime::SET.symbols }
-    register_detail(:handlers, :allow_nil => false) do
+    register_detail(:handlers) do
       Template::Handlers.extensions
     end
 

actionpack/test/controller/render_test.rb

@@ -21,6 +21,10 @@ class TestController < ActionController::Base
   def hello_world
   end
 
+  def hello_world_file
+    render :file => File.expand_path("../../fixtures/hello.html", __FILE__)
+  end
+
   def conditional_hello
     if stale?(:last_modified => Time.now.utc.beginning_of_day, :etag => [:foo, 123])
       render :action => 'hello_world'
@@ -751,6 +755,11 @@ class RenderTest < ActionController::TestCase
     assert_equal "The secret is in the sauce\n", @response.body
   end
 
+  def test_render_file
+    get :hello_world_file
+    assert_equal "Hello world!", @response.body
+  end
+
   # :ported:
   def test_render_file_as_string_with_instance_variables
     get :render_file_as_string_with_instance_variables

actionpack/test/fixtures/hello.html

@@ -0,0 +1 @@
+Hello world!