1 files changed, 2 insertions, 3 deletions
diff --git a/actionpack/lib/action_controller/metal/params_wrapper.rb b/actionpack/lib/action_controller/metal/params_wrapper.rb
index a89fc1678b..44151c9f71 100644
--- a/actionpack/lib/action_controller/metal/params_wrapper.rb
+++ b/actionpack/lib/action_controller/metal/params_wrapper.rb
@@ -159,8 +159,7 @@ module ActionController
     end
 
     included do
-      class_attribute :_wrapper_options
-      self._wrapper_options = Options.from_hash(format: [])
+      class_attribute :_wrapper_options, default: Options.from_hash(format: [])
     end
 
     module ClassMethods
@@ -283,7 +282,7 @@ module ActionController
         return false unless request.has_content_type?
 
         ref = request.content_mime_type.ref
-        _wrapper_formats.include?(ref) && _wrapper_key && !request.request_parameters[_wrapper_key]
+        _wrapper_formats.include?(ref) && _wrapper_key && !request.request_parameters.key?(_wrapper_key)
       end
   end
 end