Kitura gives me ambiguous type of expression in nested structs

Question

I'm starting to use the Kitura framework to migrate my current node.js backend to swift and I'm starting by implementing all the routes with mocked data.

Anyways, right now im at a very early stage and started to develop some mocked endpoints and deployed on IBM Cloud without any problems, they work perfectly. One example of a working endpoint is the following:

app.router.post("/getStats") { (request, response, next) in
    let mocks = Mocks()
    response.send(json: mocks.dashboard)
    next()
}

The Mocks() its a class that holds the dashboard struct with all fields predefined. Those fields are plain types (strings and numbers)

When I started to develop a more advanced endpoint, the workflow is the same, I register the route with the following code

app.router.post("/generateTest") { (request, response, next) in
    let mocks = Mocks()
    response.send(json: mocks.getTest())
    next()
}

Instead of a Codable struct with plain types, this mocked struct will have nested codable structs:

struct Test: Codable {
   var totalTime: Int
   var questions: [Question]
}

extension Test {
struct Question: Codable {
    let id: String?
    let pregunta: String
    var selectedAnswer: Answer? = nil
    let respuestas: [Answer]
    let idConcepto: Int
    let stats: Stats?
    let categorias: [String]
}

struct Answer: Codable {
    let respuesta: String
    let correcta: Bool
}

struct Stats: Codable {
    let globalStats: GlobalStats?
}

struct GlobalStats: Codable {
    let timesFailed, timesUnanswered, timesAnswered: Int?
}
}

Everything works fine when I build in localhost the project. When I navigate throught those endpoints in Postman, they return me the expected response.

The problem comes when I try to deploy this into IBM Cloud (also tried on Heroku with the same problem).

The problem it gives me its the following

/tmp/app/Sources/Application/Mocks/UserMock.swift:29:44: error: type of expression is ambiguous without more context
              let questionFirst: Test.Question = Test.Question(id: "1", pregunta: "UNO", respuestas: answers, idConcepto: 1, stats: nil, categorias: cats)
                                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I dont know how to solve this, Xcode didnt raise any errors and compiled the project locally witouth any problem, I tried to cast types and all possible combinations to generate the struct, the error is always the same.

Has somebody faced the same problem? Is this a bug with Kitura or am I missing something? In the documentation they didn't say anything about nested Structs, the only thing I found relating to nested Struct, is that Kitura ORM doesnt support nested structs when working with ORM and SQL database, which is not my case.

I would be very happy if we can find a solution

Thanks for your help

score 0 · Answer 1 · answered Jul 24 '20 at 17:18

I managed to solve the problem. As i suspected, it was a dumb thing. In Test.Question struct, the field selectedAnswer was initialized with a default value equal to nil

When i created the struct i didnt wrote that field because it has already a default value, but it looks like Kitura or deploying Swift to a server didnt support this. I instantiate the structure with the default value right now and works without any problem.

I hope this can help anyone in a future with similar problem

Kitura gives me ambiguous type of expression in nested structs

1 Answers1