lib/active_support/callbacks.rb in activesupport-7.2.2 vs lib/active_support/callbacks.rb in activesupport-8.0.0.beta1

@@ -4,11 +4,10 @@
 require "active_support/descendants_tracker"
 require "active_support/core_ext/array/extract_options"
 require "active_support/core_ext/class/attribute"
 require "active_support/core_ext/string/filters"
 require "active_support/core_ext/object/blank"
-require "thread"
 
 module ActiveSupport
   # = Active Support \Callbacks
   #
   # \Callbacks are code hooks that are run at key points in an object's life cycle.
@@ -65,10 +64,10 @@
   module Callbacks
     extend Concern
 
     included do
       extend ActiveSupport::DescendantsTracker
-      class_attribute :__callbacks, instance_writer: false, default: {}
+      class_attribute :__callbacks, instance_writer: false, instance_predicate: false, default: {}
     end
 
     CALLBACK_FILTER_TYPES = [:before, :after, :around].freeze
 
     # Runs the callbacks for the given event.