title: App crash on [[SKPaymentQueue defaultQueue] addTransactionObserver:observer];
body: <p><img src="https://i.stack.imgur.com/xTQ1z.png" alt="not much report on the crash"></p>
  
  <p>That's all I can get from the crash when I do in the <code>applicationDidBecomeActive</code></p>
  
  <pre><code>MyStoreObserver * observer = [[MyStoreObserver alloc] initWithContext:self.managedObjectContext andDelegate:self];
  
  [[SKPaymentQueue defaultQueue] addTransactionObserver:observer];
  </code></pre>
  
  <p>But the weird thing is I have been able to purchase twice in the past and even if I delete the app re-reun everything I cannot escape this pit. It doesn't seems logic. I can alloc init the observer alone without problem and I can call the default paymentQueue without problem but if I try to add the transaction observer to the queue, life stop. It's on ARC and the delegate I added to the observer is not the problem. I know for sure.</p>
  
  <p>I've added an nslog to every method in the observer and none get called before the crash</p>
  
  <p>SOLUTION FOUND</p>
  
  <p>Okay, well it looks like the observer is not retained by the queue and thus the observer needs to be an instance variable.</p>
  
  <p>Thanks</p>