in rails 4, owner is not populated when creating a join model (user.roles << role created a UserRole on the background) in rails 3, this is not a problem, in rails 4, the presence validation fails because no owner_id exists nor does an owner exist. at that moment, there’s no need to do the uniqueness validation, as it’s the user’s first roles. thus, this fix.
Added by Tom Caspy over 8 years ago
fixes #12109 - removing owner_id presence validation
in rails 4, owner is not populated when creating a join model
(user.roles << role created a UserRole on the background)
in rails 3, this is not a problem, in rails 4, the presence validation
fails because no owner_id exists nor does an owner exist. at that
moment, there’s no need to do the uniqueness validation, as it’s the
user’s first roles. thus, this fix.