Frontend sometimes sends auth_id=undefined, resulting in 500

[Hazelfire]

I've found that the frontend sometimes sends
GET https://guesstimate.herokuapp.com/users?auth0_id=undefined
The backend promptly returns a 500, Internal Server Error.

This clearly seems to be a problem with both the backend and the frontend, in that the backend is giving a 500 on an invalid input and the frontend is creating it. I'm going to see if I can look at the heroku logs for hints on what's happening.

[Hazelfire]

Ok, I can reproduce on dev. It seems to pass the id to auth0 without validation. Despite it having {"statusCode": 400 ... } in the error, this is a 500 error.

Line from the repo is here:
https://github.com/getguesstimate/guesstimate-server/blob/d1d8e82e0f7c7fa8d65270cd6eae72ad2badf5b4/lib/authentor.rb#L21

[Hazelfire]

Ok, that's odd, I managed to get a similar error even when there actually was an auth id...