Pass along original attribute to save later recursion

Fixes #26122

activerecord/lib/active_record/attribute.rb

@@ -65,7 +65,7 @@ def forgetting_assignment
 
     def with_value_from_user(value)
       type.assert_valid_value(value)
-      self.class.from_user(name, value, type, self)
+      self.class.from_user(name, value, type, original_attribute || self)
     end
 
     def with_value_from_database(value)

activerecord/test/cases/base_test.rb

@@ -115,6 +115,13 @@ def test_limit_with_comma
     end
   end
 
+  def test_many_mutations
+    car = Car.new name: "<3<3<3"
+    car.engines_count = 0
+    20_000.times { car.engines_count += 1 }
+    assert car.save
+  end
+
   def test_limit_without_comma
     assert_equal 1, Topic.limit("1").to_a.length
     assert_equal 1, Topic.limit(1).to_a.length