Merge pull request #20887 from tgxworld/ar_callbacks

Revert "Revert "Reduce allocations when running AR callbacks.""

1 files changed, 11 insertions, 3 deletions

diff --git a/activesupport/lib/active_support/callbacks.rb b/activesupport/lib/active_support/callbacks.rb
index e8ab3a7db5..f35e1f5098 100644
--- a/activesupport/lib/active_support/callbacks.rb
+++ b/activesupport/lib/active_support/callbacks.rb
@@ -80,8 +80,12 @@ module ActiveSupport
     #     save
     #   end
     def run_callbacks(kind, &block)
-      callbacks = send("_#{kind}_callbacks")
+      send "_run_#{kind}_callbacks", &block
+    end
+
+    private
 
+    def __run_callbacks__(callbacks, &block)
       if callbacks.empty?
         yield if block_given?
       else
@@ -91,8 +95,6 @@ module ActiveSupport
       end
     end
 
-    private
-
     # A hook invoked every time a before callback is halted.
     # This can be overridden in AS::Callback implementors in order
     # to provide better debugging/logging.
@@ -806,6 +808,12 @@ module ActiveSupport
         names.each do |name|
           class_attribute "_#{name}_callbacks"
           set_callbacks name, CallbackChain.new(name, options)
+
+          module_eval <<-RUBY, __FILE__, __LINE__ + 1
+            def _run_#{name}_callbacks(&block)
+              __run_callbacks__(_#{name}_callbacks, &block)
+            end
+          RUBY
         end
       end