rails/protected_attributes — pull request #20 by t27duck (2013-06-26 22:43:11+00:00)
Title: raise_nested_attributes_record_not_found was changed to a bang method in 4.0

Obviously this gem should call the bang method now too.

The change happened here and is included in the 4.0 relase: https://github.com/rails/rails/pull/10123