1 files changed, 10 insertions, 0 deletions
diff --git a/activesupport/test/descendants_tracker_without_autoloading_test.rb b/activesupport/test/descendants_tracker_without_autoloading_test.rb
index 74669aaca1..00b449af51 100644
--- a/activesupport/test/descendants_tracker_without_autoloading_test.rb
+++ b/activesupport/test/descendants_tracker_without_autoloading_test.rb
@@ -4,4 +4,14 @@ require 'descendants_tracker_test_cases'
 
 class DescendantsTrackerWithoutAutoloadingTest < ActiveSupport::TestCase
   include DescendantsTrackerTestCases
+
+  # Regression test for #8422. https://github.com/rails/rails/issues/8442
+  def test_clear_without_autoloaded_singleton_parent
+    mark_as_autoloaded do
+      parent_instance = Parent.new
+      parent_instance.singleton_class.descendants
+      ActiveSupport::DescendantsTracker.clear
+      assert !ActiveSupport::DescendantsTracker.class_variable_get(:@@direct_descendants).key?(parent_instance.singleton_class)
+    end
+  end
 end