title: Core Data Malloc Errors
body: <p>I've noticed I'm getting a few errors at random points in my app. I've had 2 errors, "double free" and "incorrect checksum for freed object". Heres the stack trace of a "double free" error. Can anyone provide any insight? It's happening on a call in my code that just sets an attribute to an <code>NSNumber</code> so I can't understand why it's doing it!</p>
  
  <pre><code>myObject.numberAttr = [NSNumber numberWithInt:[dateComponents day]];
  </code></pre>
  
  <p><strong>Randomly Triggered (Doesn't always happen):</strong></p>
  
  <pre><code>#0  0x9585b072 in malloc_error_break
  #1  0x9585c218 in szone_error
  #2  0x9585c34d in free_tiny_botch
  #3  0x01c5e064 in _PFDeallocateObject
  #4  0x01c97e2b in -[NSManagedObject(_NSInternalMethods) _setLastSnapshot__:]
  #5  0x01c97a0d in -[NSManagedObjectContext(_NSInternalChangeProcessing) _establishEventSnapshotsForObject:]
  #6  0x01c97866 in _PFFastMOCObjectWillChange
  #7  0x01c976c5 in _PF_ManagedObject_WillChangeValueForKeyIndex
  #8  0x01c97525 in _sharedIMPL_setvfk_core
  #9  0x01c9b827 in _svfk_5
  </code></pre>
  
  <p>Many thanks,</p>
  
  <p>Michael</p>