NSFetchedResultsController crashing when creating it, objc_exception_throw - ios

Question

I am receiving a objc_exception_throw when creating my NSFetchedResultsController. I am relatively new to iOS programming so I am still getting the hang of debugging iOS crashes.
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
lazy var parentContext: NSManagedObjectContext? = {
if let managedObjectContext = self.appDelegate.managedObjectContext {
return managedObjectContext
}
else {
return nil
}
}()
lazy var fetchedResultsController: NSFetchedResultsController = {
let request = NSFetchRequest()
let entity = NSEntityDescription.entityForName("GameDate", inManagedObjectContext: self.parentContext!)
request.entity = entity
let frc = NSFetchedResultsController(fetchRequest: request, managedObjectContext: self.parentContext!, sectionNameKeyPath: nil, cacheName: nil)
frc.delegate = self
return frc
}()
override func viewDidLoad() {
super.viewDidLoad()
performFetchFromDb()
setupTableView()
}
I am getting the crash on this line:
let frc = NSFetchedResultsController(fetchRequest: request, managedObjectContext: self.parentContext!, sectionNameKeyPath: nil, cacheName: nil)
Does this crash have something to do with my context?

Answer 1

I was missing an NSSortDescriptor in my fetch request. This fixed it:
lazy var fetchedResultsController: NSFetchedResultsController = {
let request = NSFetchRequest()
let entity = NSEntityDescription.entityForName("GameDate", inManagedObjectContext: self.parentContext!)
request.entity = entity
let gameTimeSort = NSSortDescriptor(key: "gameTime", ascending: false)
request.sortDescriptors = [gameTimeSort]
let frc = NSFetchedResultsController(fetchRequest: request, managedObjectContext: self.parentContext!, sectionNameKeyPath: nil, cacheName: nil)
frc.delegate = self
return frc
}()