I'm currently working on a new [repository|https://github.com/owncloud/moodle-repository_ocis] and I stumbled across an issue where when I delete a used "OAuth 2 service"  the repository list of the repository instances would crash with an SQL error.

It turned out I had to catch an exception when doing oauth2_api::get_issuer, but to find that I had to look into the code of an other repository. It would be much better if the documentation would tell the developer which exception is thrown.