Prevent double firing the before save callback of new object when the parent association saved in the callback

Related #18155, #26661, 268a5bb, #27434, #27442, and #28599.

Originally #18155 was introduced for preventing double insertion caused
by the after save callback. But it was caused the before save issue
(#26661). 268a5bb fixed #26661, but it was caused the performance
regression (#27434). #27442 added new record to `target` before calling
callbacks for fixing #27434. But it was caused double firing before save
callback (#28599). We cannot add new object to `target` before saving
the object.

This is improving #18155 to only track callbacks after `save`.

Fixes #28599.

1 files changed, 16 insertions, 2 deletions

diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
index e2f044c139..25133fc580 100644
--- a/activerecord/test/cases/associations/has_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -2447,15 +2447,29 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_equal [first_bulb, second_bulb], car.bulbs
   end
 
-  test "double insertion of new object to association when same association used in the after create callback of a new object" do
+  test "prevent double insertion of new object when the parent association loaded in the after save callback" do
     reset_callbacks(:save, Bulb) do
       Bulb.after_save { |record| record.car.bulbs.load }
+
       car = Car.create!
       car.bulbs << Bulb.new
+
       assert_equal 1, car.bulbs.size
     end
   end
 
+  test "prevent double firing the before save callback of new object when the parent association saved in the callback" do
+    reset_callbacks(:save, Bulb) do
+      count = 0
+      Bulb.before_save { |record| record.car.save && count += 1 }
+
+      car = Car.create!
+      car.bulbs.create!
+
+      assert_equal 1, count
+    end
+  end
+
   class AuthorWithErrorDestroyingAssociation < ActiveRecord::Base
     self.table_name = "authors"
     has_many :posts_with_error_destroying,
@@ -2496,7 +2510,7 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
 
   def test_loading_association_in_validate_callback_doesnt_affect_persistence
     reset_callbacks(:validation, Bulb) do
-      Bulb.after_validation { |m| m.car.bulbs.load }
+      Bulb.after_validation { |record| record.car.bulbs.load }
 
       car = Car.create!(name: "Car")
       bulb = car.bulbs.create!