When I was reviewing this new feature I failed to test the changing of the file name. The documentation states to use 'file_name' as the parameter but internally it is 'filename'. So I get the error: The requested method 'Bugzilla::Attachment::set_file_name' was not found. I will create a patch that converts 'file_name' to 'filename' before set_all() so that we can keep the param naming for attachments consistent.
This change is now live. If there are any issues, do not reopen this bug. Instead, you should create a new bug and reference this bug. -- simon