Realm Swift subclassing - swift

Question

I have two models that I am trying to subclass in swift using RealmSwift
Model 1: Users
#objcMembers class User: Object, Codable {
dynamic var id: Int = 0
dynamic var username: String = ""
dynamic var email: String = ""
dynamic var counts: Counts = Counts(follows: 0, followed_by: 0)
convenience init(id: Int, username: String, email: String, counts: Counts) {
self.init()
self.id = id
self.username = username
self.email = email
self.counts = counts
}
}
class Counts: Codable {
let follows: Int
let followed_by: Int
init(follows: Int, followed_by: Int) {
self.follows = follows
self.followed_by = followed_by
}
}
Here I created a model which inherits codable because I am using Swift 4 new decoding method. This model works fine. I can go add a user and read it fine. So doing this works fine:
let newUser = User(id: 1, username: "user1", email: "user1#gmail.com", counts: Counts(follows: 100, followed_by: 500000000))
RealmService.shared.write(newUser)
Now I am trying to create a model called Friend which has a field that inherits from User
Model 2: Friend
#objcMembers class Friend: Object {
dynamic var user: User = User(id: 0, username: "", email: "", counts: Counts(follows: 0, followed_by: 0))
dynamic var dateAdded: Date = Date(timeIntervalSinceNow: 0)
convenience init(user: User, dateAdded: Date = Date(timeIntervalSinceNow: 0)) {
self.init()
self.user = user
self.dateAdded = dateAdded
}
}
When I do this and load up my app I get a SIGBART and it highlights my initialization of realm : let realm = RealmService.shared.realm
When I remove my Friend Model the app works fine.
How do you properly subclass in Realm?

Answer 1

You cannot declare properties as normal Swift properties whose types are other Realm subclasses. What you are looking for is a many-to-one relationship.
Many-to-one relationships have to be declared optionals and you can't provide a default value
#objcMembers class Friend: Object {
dynamic var user: User?
dynamic var dateAdded: Date = Date()
convenience init(user: User, dateAdded: Date = Date()) {
self.init()
self.user = user
self.dateAdded = dateAdded
}
}
Unrelated, but when you want to create a Date object representing the current time, just call the default, empty initializer of Date, it will do that for you and it's much shorter than Date(timeIntervalSinceNow: 0).