Merge pull request rails#53330 from Shopify/active-model-dirty-skip-reset

ActiveModel::Dirty: only reset original values for persisted records

Author: byroot

activemodel/lib/active_model/dirty.rb

@@ -247,7 +247,7 @@ module Dirty
 
     def initialize_dup(other) # :nodoc:
       super
-      if self.class.respond_to?(:_default_attributes)
+      if other.persisted? && self.class.respond_to?(:_default_attributes)
         @attributes = self.class._default_attributes.map do |attr|
           attr.with_value_from_user(@attributes.fetch_value(attr.name))
         end

activemodel/test/cases/dirty_test.rb

@@ -5,6 +5,7 @@
 
 class DirtyTest < ActiveModel::TestCase
   class DirtyModel
+    include ActiveModel::API
     include ActiveModel::Dirty
     define_attribute_methods :name, :color, :size, :status