Arguably, the rails-team's choice of raising ArgumentError instead of validation error is correct in the sense that we have full control over what options a user can select from a radio buttons group, or can select over a select field, so if a programmer happens to add a new radio button that has a typo for its value, then it is good to raise an error as it is an application error, and not a user error. However, for APIs, this will not work because we do not have any control anymore on what values get sent to the server.

When the controller creates the user, instead of adding a validation error to the record, it raises an exception. How to avoid this?

But now the first line throws an exception ArgumentError: '0' is not a valid audience

Unfortunately, it also gets the other properties, including bringing down the whole system when it crashes. This matters because systemd is complex

“Code without tests is broken by design”