Open Radar

 
Area:
UIKit

Summary:
If the same NSIndexPath is included in the array provided to -[UICollectionView deleteItemsAtIndexPaths:] more than once, eventually there will be an EXC_BAD_ACCESS in -[UICollectionViewData layoutAttributesForItemAtIndexPath:].

Say I have an NSMutableArray of data powering the data source of my UICollectionView, if I wanted to delete the head element twice, I might do something like:

[self.collectionView performBatchUpdates:^{
  NSArray *paths = @[
    [NSIndexPath indexPathForItem:0 inSection:0],
    [NSIndexPath indexPathForItem:0 inSection:0]
  ];
  [self.data removeObjectAtIndex:0];
  [self.data removeObjectAtIndex:0];
  [self.collectionView deleteItemsAtIndexPaths:paths];
} completion:nil];

If I repeat this action, or do other batch updates, eventually it will crash.

Steps to Reproduce:
1. Open sample app provided
2. Tap "Play" nav bar item a few times
3. Observe crash

Expected Results:
Delete the first two elements each time, don't crash.

Actual Results:
It will delete the first two elements, but after a few times tapping the "Play" item, it will crash.

Version:
10.3.1 (14E304)

Notes:


Configuration:
7 simulator, iPhone 7+

Attachments:
'UICollectionViewMultipleDeletesSameIndex.zip' and 'UICollectionViewMultipleDeletesSameIndex  4-24-17, 9-13 AM.crash' were successfully uploaded.