`ActiveRecord::Base#becomes` should retain the errors of the original object.

This commit contains a simple failing test that demonstrates the behaviour we expect, and a fix. When using `becomes` to transform the type of an object, it should retain any error information that was present on the original instance.

1 files changed, 8 insertions, 0 deletions

diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index fdb656fe13..997c9e7e9d 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -1761,6 +1761,14 @@ class BasicsTest < ActiveRecord::TestCase
     assert_equal "The First Topic", topics(:first).becomes(Reply).title
   end
 
+  def test_becomes_includes_errors
+    company = Company.new(:name => nil)
+    assert !company.valid?
+    original_errors = company.errors
+    client = company.becomes(Client)
+    assert_equal original_errors, client.errors
+  end
+
   def test_silence_sets_log_level_to_error_in_block
     original_logger = ActiveRecord::Base.logger
     log = StringIO.new