2 files changed, 2 insertions, 5 deletions
diff --git a/actionpack/lib/action_controller/metal.rb b/actionpack/lib/action_controller/metal.rb
index 1641d01c30..f6e67b02d7 100644
--- a/actionpack/lib/action_controller/metal.rb
+++ b/actionpack/lib/action_controller/metal.rb
@@ -175,10 +175,7 @@ module ActionController
       body = [body] unless body.nil? || body.respond_to?(:each)
       response.reset_body!
       return unless body
-      body.each { |part|
-        next if part.empty?
-        response.write part
-      }
+      response.body = body
       super
     end
 
diff --git a/actionpack/lib/action_controller/metal/strong_parameters.rb b/actionpack/lib/action_controller/metal/strong_parameters.rb
index 89b4f12ef7..e17189f9f9 100644
--- a/actionpack/lib/action_controller/metal/strong_parameters.rb
+++ b/actionpack/lib/action_controller/metal/strong_parameters.rb
@@ -602,7 +602,7 @@ module ActionController
       end
 
       def fields_for_style?
-        @parameters.all? { |k, v| k =~ /\A-?\d+\z/ && v.is_a?(Hash) }
+        @parameters.all? { |k, v| k =~ /\A-?\d+\z/ && (v.is_a?(Hash) || v.is_a?(Parameters)) }
       end
 
     private