Merge pull request rails#49836 from skipkayhil/hm-assign-attribute-respond-to

Remove respond_to? in assign_attribute happy path

Author: jonathanhefner

activemodel/lib/active_model/attribute_assignment.rb

@@ -45,8 +45,10 @@ def _assign_attributes(attributes)
 
       def _assign_attribute(k, v)
         setter = :"#{k}="
+        public_send(setter, v)
+      rescue NoMethodError
         if respond_to?(setter)
-          public_send(setter, v)
+          raise
         else
           raise UnknownAttributeError.new(self, k.to_s)
         end