Revert "Remove update_attribute."

This reverts commit a7f4b0a1231bf3c65db2ad4066da78c3da5ffb01.

Conflicts:
	activerecord/lib/active_record/associations/has_one_association.rb
	activerecord/lib/active_record/persistence.rb
	activerecord/test/cases/base_test.rb
	activerecord/test/cases/dirty_test.rb
	activerecord/test/cases/timestamp_test.rb

1 files changed, 11 insertions, 1 deletions

diff --git a/activerecord/test/cases/dirty_test.rb b/activerecord/test/cases/dirty_test.rb
index 92677b9926..9a2a5a4e3c 100644
--- a/activerecord/test/cases/dirty_test.rb
+++ b/activerecord/test/cases/dirty_test.rb
@@ -509,6 +509,16 @@ class DirtyTest < ActiveRecord::TestCase
     assert_not_nil pirate.previous_changes['updated_on'][1]
     assert !pirate.previous_changes.key?('parrot_id')
     assert !pirate.previous_changes.key?('created_on')
+
+    pirate = Pirate.find_by_catchphrase("Ahoy!")
+    pirate.update_attribute(:catchphrase, "Ninjas suck!")
+
+    assert_equal 2, pirate.previous_changes.size
+    assert_equal ["Ahoy!", "Ninjas suck!"], pirate.previous_changes['catchphrase']
+    assert_not_nil pirate.previous_changes['updated_on'][0]
+    assert_not_nil pirate.previous_changes['updated_on'][1]
+    assert !pirate.previous_changes.key?('parrot_id')
+    assert !pirate.previous_changes.key?('created_on')
   end
 
   if ActiveRecord::Base.connection.supports_migrations?
@@ -534,7 +544,7 @@ class DirtyTest < ActiveRecord::TestCase
 
       pirate = target.create(:created_on => created_on)
       pirate.reload # Here mysql truncate the usec value to 0
-      
+
       pirate.created_on = created_on
       assert !pirate.created_on_changed?
     end