AR::Base#clone fixed to set dirty bits for cloned object

[#2919 state:committed]

Signed-off-by: Jeremy Kemper <jeremy@bitsweat.net>

activerecord/lib/active_record/base.rb

@@ -1463,12 +1463,18 @@ module ActiveRecord #:nodoc:
         callback(:after_initialize) if respond_to_without_attributes?(:after_initialize)
         cloned_attributes = other.clone_attributes(:read_attribute_before_type_cast)
         cloned_attributes.delete(self.class.primary_key)
+
         @attributes = cloned_attributes
+
+        @changed_attributes = {}
+        attributes_from_column_definition.each do |attr, orig_value|
+          @changed_attributes[attr] = orig_value if field_changed?(attr, orig_value, @attributes[attr])
+        end
+
         clear_aggregation_cache
         @attributes_cache = {}
         @new_record = true
         ensure_proper_type
-        @changed_attributes = other.changed_attributes.dup
 
         if scope = self.class.send(:current_scoped_methods)
           create_with = scope.scope_for_create

activerecord/test/cases/base_test.rb

@@ -1456,6 +1456,56 @@ class BasicsTest < ActiveRecord::TestCase
     assert_kind_of Client, clone
   end
 
+  def test_clone_of_new_object_with_defaults
+    developer = Developer.new
+    assert !developer.name_changed?
+    assert !developer.salary_changed?
+
+    cloned_developer = developer.clone
+    assert !cloned_developer.name_changed?
+    assert !cloned_developer.salary_changed?
+  end
+
+  def test_clone_of_new_object_marks_attributes_as_dirty
+    developer = Developer.new :name => 'Bjorn', :salary => 100000
+    assert developer.name_changed?
+    assert developer.salary_changed?
+
+    cloned_developer = developer.clone
+    assert cloned_developer.name_changed?
+    assert cloned_developer.salary_changed?
+  end
+
+  def test_clone_of_new_object_marks_as_dirty_only_changed_attributes
+    developer = Developer.new :name => 'Bjorn'
+    assert developer.name_changed?            # obviously
+    assert !developer.salary_changed?         # attribute has non-nil default value, so treated as not changed
+
+    cloned_developer = developer.clone
+    assert cloned_developer.name_changed?
+    assert !cloned_developer.salary_changed?  # ... and cloned instance should behave same
+  end
+
+  def test_clone_of_saved_object_marks_attributes_as_dirty
+    developer = Developer.create! :name => 'Bjorn', :salary => 100000
+    assert !developer.name_changed?
+    assert !developer.salary_changed?
+
+    cloned_developer = developer.clone
+    assert cloned_developer.name_changed?     # both attributes differ from defaults
+    assert cloned_developer.salary_changed?
+  end
+
+  def test_clone_of_saved_object_marks_as_dirty_only_changed_attributes
+    developer = Developer.create! :name => 'Bjorn'
+    assert !developer.name_changed?           # both attributes of saved object should be threated as not changed
+    assert !developer.salary_changed?
+
+    cloned_developer = developer.clone
+    assert cloned_developer.name_changed?     # ... but on cloned object should be
+    assert !cloned_developer.salary_changed?  # ... BUT salary has non-nil default which should be threated as not changed on cloned instance
+  end
+
   def test_bignum
     company = Company.find(1)
     company.rating = 2147483647