error creating object using Firebase values - ios

Question

I am attempting to pull down information from my Firebase database and use it to create an object of type Order. The error that I have printed in the catch statement is as follows.
Error Domain=myProjectName.OrderError Code=0 "(null)"
I am unsure what this means exactly, or how to fix it.
I have defined a custom error type in my Order class, as shown below.
enum OrderError: ErrorType
{
case IllegalOrderNumber
case InvalidEntry
}
The error is generated by the following code snippet.
self.ref.child("orders").observeEventType(.ChildAdded, withBlock: { (snapshot) in
let pickupLoc = snapshot.value!["pickupLocation"] as? String
let dropoffLoc = snapshot.value!["dropoffLocation"] as? String
let orderNumInt = snapshot.value!["orderNum"] as? Int
//since the database will return nil if you try and cast a string to an int
//we get it as an int then cast to string
let orderNum = String(orderNumInt)
do
{
let myOrder = try Order(PickUpLoc: pickupLoc, DropOffLoc: dropoffLoc, OrderNum: orderNum)!
self.orders.append(myOrder)
}
catch let error as NSError
{
//should never get here
print(error)
}
})
I do all of the error checking when the user enters the value into the database, so there should be no reason for there to be an error generated.

Answer 1

Okay, so after combing through my code I noticed two primary possible error sources. Firstly, despite the compiler not complaining, the do-catch block was not exhaustive, and therefore an additional catch was added to fix this. Secondly, I believe the error was generated by the fact that I declared my Orders array as var orders = [Order()] as opposed to var orders = [Order](), when I changed this, the program ran smoothly.