从 'AFError?' 到不相关的类型 'URLError' 总是失败警告

Question

I'm getting this warning Cast from 'AFError?' to unrelated type 'URLError' always fails Cast from 'AFError?' to unrelated type 'URLError' always fails when I try to cast the error in the following function

func requestBlock() {
    struct ValidationConsumer: ResponseDelegate {
        weak var syncRequest: Transfer_PurchaseValidation?
        var productIdentifier: String

        func didSucceed(_ _: JSON, _ _: AFDataResponse<Any>?) {
            DDLogInfo("Purchase payload for productId = \(productIdentifier) was sent")
            syncRequest?.didSucceed()
        }

        func didFail(_ json: JSON, _ code: Int?, _ dataResponse: AFDataResponse<Any>?) {
            syncRequest?.didFail(with: .PurchaseValidationError(code,
                    dataResponse?.error as? URLError))
        }
    }

    guard data.shouldBeTransferred else {
        return
    }

    guard isUnderTest == nil else {
        executeTestsequence()
        return
    }

    guard let receiptDataString = data.receiptDataString,
          let productIdentifier = data.productIdentifier else {
        didFail(with: .InvalidData); return
    }

    let validationConsumer = ValidationConsumer(syncRequest: self,
            productIdentifier: productIdentifier)
    self.validatePurchase(receiptDataString, productIdentifier,
            validationDelegate: validationConsumer)
}

at this part syncRequest?.didFail(with: .PurchaseValidationError(code, dataResponse?.error as? URLError))

I tried to use NSError or Error classes but no success.

Can anyone let me know how I can get rid of this warning?

Thanks in advance

Answer 1

Alamofire returns AFError instances by default which are not convertible to URLError . You can examine the AFError documentation or source code for the full details, but underlying errors like network failures are exposed through the underlyingError property. So in the case of a network failure, response?.error?.underlyingError as? URLError response?.error?.underlyingError as? URLError should give you the correct value, but only if the underlying error is actually a URLError .

Ultimately I suggest you handle the AFError directly, as it's the only full representation of all of the errors Alamofire can return. Either that, or your own error type which does the handling for you. Casting is not the correct way to capture these errors, as any cast will lose some error information.

Answer 2

I had a problem similar to yours. I made a model as follows:

struct MyErorr: Error {
    
    public var errorCode: Int
    public var erorrMessage: String
}

and create object from myError this error part like this:

// error instance from AFError

if error.responseCode == 401 {
    let myError: MyErorr = .init(errorCode: 401, erorrMessage: "Unauthorized")
    callback(myError)
    
} else { ... }

I hope it is useful for you

Answer 3

The solution was to add another cast. So, instead of

syncRequest?.didFail(with: .PurchaseValidationError(code,

                    dataResponse?.error as? URLError))

I did the case as following

syncRequest?.didFail(with: .PurchaseValidationError(code, 
                    dataResponse?.error as NSError? as? URLError))