失败的初始化器无法满足非失败的初始化器要求

Question

I have this struct and I want its init to be failable because something could go wrong with the JSON dictionary I pass:

struct AdminModel:Interface{

var status:Any = ""
var l:String = ""
var p:String = ""
var url:String = ""

init?(json:NSDictionary){

    if let status = json["status"] as? Any,
       let l = json["l"] as? String,
       let p = json["p"] as? String,
       let url = json["url"] as? String
    {
        self.status = status
        self.l = l
        self.p = p
        self.url = url
    }else{
        return nil
    }
}

}

There's no issue until I add ? after init to make init failable : at that point XCode complains:

Non-failable initializer requirement 'init(json:)' cannot be satisfied by failable initializer ('init?')

Why my struct can't be failable? Should I declare failable even the protocol init?

Answer 1

Maybe your Interface is like:

protocol Interface {
   init(json: JSON)
}

but your AdminModel's init is init?(json: JSON) , so you should keep consistent:

protocol Interface {
   init?(json: JSON)
}