It seems a class, which uses generics in swift, sometimes cannot properly determine object type.
Consider the following model structure:
class BaseModel: NSObject, Equatable, Printable {
var id: String = ""
override var description: String {
return "id: \(id)"
}
override func isEqual(object: AnyObject?) -> Bool {
if let object = object as? BaseModel {
return object.id == id
}
else {
return super.isEqual(object)
}
}
}
class Image: BaseModel {
var image: UIImage!
}
I also have parsers, which should parse/serialize objects:
class AbstractParser<T: BaseModel where T: Equatable>: NSObject {
func convertFromParseObject(object: NSObject) -> T {
var entity = T()
......
return updateEntityWithParseObject(object, entity: entity)
}
func updateEntityWithParseObject(object: NSObject, entity: T) -> T {
fatalError("This method must be overridden")
}
}
class ImageParser<T: Image>: AbstractParser<Image> {
override func updateEntityWithParseObject(object: NSObject, entity: Image) -> Image {
println("\(entity)")
println("\(entity.id)")
// The line below outputs BaseModel, shouldn't it be Image instead?
println("\(NSStringFromClass(entity.classForCoder))")
// EXC_BAD_ACCESS here:
println("\(entity.image)")
return entity
}
}
The app crashes when I try to access entity.image.
For some reasons Swift thinks that entity object is BaseModel, not Image.
Playground file: https://drive.google.com/file/d/0B6agzpK_lR6JQUlhMFoxaGw1akU/view?usp=sharing
