Open Radar

 
This should probably be forwarded to the UIKit team, and is likely a dupe Apple is already aware of...

Summary:

When using UICollectionView's -performBatchUpdates: method to respond to changes initiated by the delegate callbacks from an NSFetchedResultsController, an exception is thrown:

CoreData: error: Serious application error.  An exception was caught from the delegate of NSFetchedResultsController during a call to -controllerDidChangeContent:.  *** -[__NSArrayM objectAtIndex:]: index 1 beyond bounds for empty array with userInfo (null)

At first it seems like this is a Core Data or NSFetchedResultsController error, however UICollectionViewFlowLayout is the offending class that is calling index out of bounds. Attached you'll see a stack trace that's stopped by an exception breakpoint.

This exception happens when the collection view is using supplemental views (i.e. header or footer views).

I think it is *likely* to be replicated without using NSFetchedResultsController (which would result in an immediate crash since the exception is not caught and handled).

Thanks!

(NOTE: Attached http://i.stack.imgur.com/8lPvP.png )