1 files changed, 0 insertions, 111 deletions
diff --git a/activerecord/lib/active_record/attribute_mutation_tracker.rb b/activerecord/lib/active_record/attribute_mutation_tracker.rb
deleted file mode 100644
index 94bf641a5d..0000000000
--- a/activerecord/lib/active_record/attribute_mutation_tracker.rb
+++ /dev/null
@@ -1,111 +0,0 @@
-# frozen_string_literal: true
-
-module ActiveRecord
-  class AttributeMutationTracker # :nodoc:
-    OPTION_NOT_GIVEN = Object.new
-
-    def initialize(attributes)
-      @attributes = attributes
-      @forced_changes = Set.new
-    end
-
-    def changed_values
-      attr_names.each_with_object({}.with_indifferent_access) do |attr_name, result|
-        if changed?(attr_name)
-          result[attr_name] = attributes[attr_name].original_value
-        end
-      end
-    end
-
-    def changes
-      attr_names.each_with_object({}.with_indifferent_access) do |attr_name, result|
-        change = change_to_attribute(attr_name)
-        if change
-          result[attr_name] = change
-        end
-      end
-    end
-
-    def change_to_attribute(attr_name)
-      attr_name = attr_name.to_s
-      if changed?(attr_name)
-        [attributes[attr_name].original_value, attributes.fetch_value(attr_name)]
-      end
-    end
-
-    def any_changes?
-      attr_names.any? { |attr| changed?(attr) }
-    end
-
-    def changed?(attr_name, from: OPTION_NOT_GIVEN, to: OPTION_NOT_GIVEN)
-      attr_name = attr_name.to_s
-      forced_changes.include?(attr_name) ||
-        attributes[attr_name].changed? &&
-        (OPTION_NOT_GIVEN == from || attributes[attr_name].original_value == from) &&
-        (OPTION_NOT_GIVEN == to || attributes[attr_name].value == to)
-    end
-
-    def changed_in_place?(attr_name)
-      attributes[attr_name.to_s].changed_in_place?
-    end
-
-    def forget_change(attr_name)
-      attr_name = attr_name.to_s
-      attributes[attr_name] = attributes[attr_name].forgetting_assignment
-      forced_changes.delete(attr_name)
-    end
-
-    def original_value(attr_name)
-      attributes[attr_name.to_s].original_value
-    end
-
-    def force_change(attr_name)
-      forced_changes << attr_name.to_s
-    end
-
-    # TODO Change this to private once we've dropped Ruby 2.2 support.
-    # Workaround for Ruby 2.2 "private attribute?" warning.
-    protected
-
-      attr_reader :attributes, :forced_changes
-
-    private
-
-      def attr_names
-        attributes.keys
-      end
-  end
-
-  class NullMutationTracker # :nodoc:
-    include Singleton
-
-    def changed_values(*)
-      {}
-    end
-
-    def changes(*)
-      {}
-    end
-
-    def change_to_attribute(attr_name)
-    end
-
-    def any_changes?(*)
-      false
-    end
-
-    def changed?(*)
-      false
-    end
-
-    def changed_in_place?(*)
-      false
-    end
-
-    def forget_change(*)
-    end
-
-    def original_value(*)
-    end
-  end
-end