I am testing Parse local datastore to evaluate if I can use it as a replacement for SQLite for an app that would mostly be used offline. I may have found a bug?

Consider the Product and Order classes:

```
class Product : PFObject, PFSubclassing {
    @NSManaged var productName: String!
}

class Order : PFObject, PFSubclassing {
    @NSManaged var orderId: String!
    @NSManaged var product: Product!
}

```

With internet disabled, when I run the following code, it crashes on the last line with `Tried to save an object with a new, unsaved child.`

```
let p = Product()
p.productName = "Test Product"
p.saveEventually()

let o = Order()
o.orderId = "TestOrder01"
o.product = p
o.saveEventually()

let query = Order.query()
query.whereKey("product", equalTo: p)

let results = query.findObjects() // crashes with Tried to save an object with a new, unsaved child.

```

is it a platform limitation or a bug in my code?

**NOTE** I have typed the code from memory, so ignore minor issues.