1 files changed, 6 insertions, 3 deletions
diff --git a/activerecord/lib/active_record/readonly_attributes.rb b/activerecord/lib/active_record/readonly_attributes.rb
index 836b15e2ce..b3c20c4aff 100644
--- a/activerecord/lib/active_record/readonly_attributes.rb
+++ b/activerecord/lib/active_record/readonly_attributes.rb
@@ -1,12 +1,10 @@
-require 'active_support/concern'
-require 'active_support/core_ext/class/attribute'
 
 module ActiveRecord
   module ReadonlyAttributes
     extend ActiveSupport::Concern
 
     included do
-      config_attribute :_attr_readonly
+      class_attribute :_attr_readonly, instance_accessor: false
       self._attr_readonly = []
     end
 
@@ -22,5 +20,10 @@ module ActiveRecord
         self._attr_readonly
       end
     end
+
+    def _attr_readonly
+      ActiveSupport::Deprecation.warn("Instance level _attr_readonly method is deprecated, please use class level method.")
+      defined?(@_attr_readonly) ? @_attr_readonly : self.class._attr_readonly
+    end
   end
 end