Alright, so I’m quite new to the Elixir universe, so if I’m overlooking anything obvious, please tell me.
I’m trying to validate if a user has a certain role to check if they are allowed to execute the current query. (This will also checked in the frontend but I also want to make sure the api endpoint is not misused).
So, the user can have a set of roles that I get as an array, e.g. [“Role1”, “Role2”, “Role3”] but could also be empty if they are a normal user with no special roles at all.
In my Ecto Schema, I have a virtual filed “roles” where I save said array. Now I thought I could validate it with validate_subset( changeset, :roles, [“TheAllowedRole”, “TheOtherAllowedRole”]) which works great if my array has entries. But if it is empty, it doesn’t throw an validation error which is not what I would expect.
My immediate thought is to use an additional validate_length with min 1 entry. Is this the best procedure or did I do something wrong or would you recommend using another method all together?
Thank you for your help! 
