Type 'X' does not conform to protocol 'ResponseObjectSerializable'

Question

I try to make custom response serialization with Alamofire

I follow what written in README and create protocol and extension

@objc public protocol ResponseObjectSerializable {
    init?(response: NSHTTPURLResponse, representation: AnyObject)
}

extension Alamofire.Request {
    public func responseObject<T: ResponseObjectSerializable>(completionHandler: (NSURLRequest, NSHTTPURLResponse?, T?, NSError?) -> Void) -> Self {
        let serializer: Serializer = { (request, response, data) in
            let JSONSerializer = Request.JSONResponseSerializer(options: .AllowFragments)
            let (JSON: AnyObject?, serializationError) = JSONSerializer(request, response, data)
            if response != nil && JSON != nil {
                return (T(response: response!, representation: JSON!), nil)
            } else {
                return (nil, serializationError)
            }
        }

        return response(serializer: serializer, completionHandler: { (request, response, object, error) in
            completionHandler(request, response, object as? T, error)
        })
    }
}

but when I try to conform it I got this error Type 'my_model_class' does not conform to protocol 'ResponseObjectSerializable'

My model is just a bare-bone class

final class Shot: ResponseObjectSerializable {
    required init?(response: NSHTTPURLResponse, representation: AnyObject) {
    }
}

Use this with Xcode 6.3, anyone experienced this? and know how to make this work?

Response to @airspeed The error go away, but what confusing me is in Apple Swift document they have an example on @objc protocol and the swift class that conform it doesn't need @objc

@objc protocol CounterDataSource {
    optional func incrementForCount(count: Int) -> Int
    optional var fixedIncrement: Int { get }
}

class TowardsZeroSource: CounterDataSource {
    func incrementForCount(count: Int) -> Int {
        if count == 0 {
            return 0
        } else if count < 0 {
            return 1
        } else {
            return -1
        }
    }
}

Answer 1

Shot isn't marked as @objc , unlike the protocol, so your init doesn't match the requirement:

@objc public protocol ResponseObjectSerializable {
    init?(response: NSHTTPURLResponse, representation: AnyObject)
}

final class Shot: ResponseObjectSerializable {
    @objc required init?(response: NSHTTPURLResponse, representation: AnyObject) {
    }
}

results in the error:

note: protocol requires initializer init(response:representation:) with type (response: NSHTTPURLResponse, representation: AnyObject)

  init?(response: NSHTTPURLResponse, representation: AnyObject)` ^ 

note: candidate is not @objc , but protocol requires it

Stick an @objc in front of the definition of Shot and it should compile.