1 files changed, 16 insertions, 1 deletions
diff --git a/activerecord/lib/active_record/attribute_set.rb b/activerecord/lib/active_record/attribute_set.rb
index 013a7d0e01..be581ac2a9 100644
--- a/activerecord/lib/active_record/attribute_set.rb
+++ b/activerecord/lib/active_record/attribute_set.rb
@@ -60,8 +60,14 @@ module ActiveRecord
       super
     end
 
+    def deep_dup
+      dup.tap do |copy|
+        copy.instance_variable_set(:@attributes, attributes.deep_dup)
+      end
+    end
+
     def initialize_dup(_)
-      @attributes = attributes.deep_dup
+      @attributes = attributes.dup
       super
     end
 
@@ -80,6 +86,15 @@ module ActiveRecord
       attributes.select { |_, attr| attr.has_been_read? }.keys
     end
 
+    def map(&block)
+      new_attributes = attributes.transform_values(&block)
+      AttributeSet.new(new_attributes)
+    end
+
+    def ==(other)
+      attributes == other.attributes
+    end
+
     protected
 
     attr_reader :attributes