1 files changed, 7 insertions, 23 deletions
diff --git a/activerecord/lib/active_record/attribute_mutation_tracker.rb b/activerecord/lib/active_record/attribute_mutation_tracker.rb
index 08eb8ba7ac..ba7348918b 100644
--- a/activerecord/lib/active_record/attribute_mutation_tracker.rb
+++ b/activerecord/lib/active_record/attribute_mutation_tracker.rb
@@ -1,14 +1,13 @@
 module ActiveRecord
   class AttributeMutationTracker # :nodoc:
-    def initialize(attributes, original_attributes)
+    def initialize(attributes)
       @attributes = attributes
-      @original_attributes = original_attributes
     end
 
     def changed_values
       attr_names.each_with_object({}.with_indifferent_access) do |attr_name, result|
         if changed?(attr_name)
-          result[attr_name] = original_attributes.fetch_value(attr_name)
+          result[attr_name] = attributes[attr_name].original_value
         end
       end
     end
@@ -16,49 +15,34 @@ module ActiveRecord
     def changes
       attr_names.each_with_object({}.with_indifferent_access) do |attr_name, result|
         if changed?(attr_name)
-          result[attr_name] = [original_attributes.fetch_value(attr_name), attributes.fetch_value(attr_name)]
+          result[attr_name] = [attributes[attr_name].original_value, attributes.fetch_value(attr_name)]
         end
       end
     end
 
     def changed?(attr_name)
       attr_name = attr_name.to_s
-      modified?(attr_name) || changed_in_place?(attr_name)
+      attributes[attr_name].changed?
     end
 
     def changed_in_place?(attr_name)
-      original_database_value = original_attributes[attr_name].value_before_type_cast
-      attributes[attr_name].changed_in_place_from?(original_database_value)
+      attributes[attr_name].changed_in_place?
     end
 
     def forget_change(attr_name)
       attr_name = attr_name.to_s
-      original_attributes[attr_name] = attributes[attr_name].dup
-    end
-
-    def now_tracking(new_attributes)
-      AttributeMutationTracker.new(new_attributes, clean_copy_of(new_attributes))
+      attributes[attr_name] = attributes[attr_name].forgetting_assignment
     end
 
     protected
 
-    attr_reader :attributes, :original_attributes
+    attr_reader :attributes
 
     private
 
     def attr_names
       attributes.keys
     end
-
-    def modified?(attr_name)
-      attributes[attr_name].changed_from?(original_attributes.fetch_value(attr_name))
-    end
-
-    def clean_copy_of(attributes)
-      attributes.map do |attr|
-        attr.with_value_from_database(attr.value_for_database)
-      end
-    end
   end
 
   class NullMutationTracker # :nodoc: