lib/active_support/callbacks.rb in activesupport-5.0.0.beta1 vs lib/active_support/callbacks.rb in activesupport-5.0.0.beta1.1

@@ -69,11 +69,11 @@
 
     # If true, Active Record and Active Model callbacks returning +false+ will
     # halt the entire callback chain and display a deprecation message.
     # If false, callback chains will only be halted by calling +throw :abort+.
     # Defaults to +true+.
-    mattr_accessor(:halt_and_display_warning_on_return_false) { true }
+    mattr_accessor(:halt_and_display_warning_on_return_false, instance_writer: false) { true }
 
     # Runs the callbacks for the given event.
     #
     # Calls the before and around callbacks in the order they were set, yields
     # the block (if given one), and then runs the after callbacks in reverse
@@ -740,10 +740,10 @@
       # `!`, `?` or `=`.
       def define_callbacks(*names)
         options = names.extract_options!
 
         names.each do |name|
-          class_attribute "_#{name}_callbacks"
+          class_attribute "_#{name}_callbacks", instance_writer: false
           set_callbacks name, CallbackChain.new(name, options)
 
           module_eval <<-RUBY, __FILE__, __LINE__ + 1
             def _run_#{name}_callbacks(&block)
               __run_callbacks__(_#{name}_callbacks, &block)