Use instance_accessor: false instead of instance_writer.

1 files changed, 6 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/readonly_attributes.rb b/activerecord/lib/active_record/readonly_attributes.rb
index 1d8c566e40..b3c20c4aff 100644
--- a/activerecord/lib/active_record/readonly_attributes.rb
+++ b/activerecord/lib/active_record/readonly_attributes.rb
@@ -4,7 +4,7 @@ module ActiveRecord
     extend ActiveSupport::Concern
 
     included do
-      class_attribute :_attr_readonly, instance_writer: false
+      class_attribute :_attr_readonly, instance_accessor: false
       self._attr_readonly = []
     end
 
@@ -20,5 +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