Bad Access on [UICollectionView setCollectionViewLayout:animated:]

Question

I'm getting a strange crash in my UICollectionView. The crashing UICollectionView is embedded in an UICollectionView cell of another UICollectionView.

I can't reproduce the issue, it seems to happen sometimes if the inner UICollectionView get's newly initialized because the outer CollectionView is reloading it's cells.

com.apple.main-thread Crashed
0   libobjc.A.dylib     objc_msgSend + 9
1   UIKit   -[UICollectionViewData _setLayoutAttributes:atGlobalItemIndex:] + 60
2   UIKit   __45-[UICollectionViewData validateLayoutInRect:]_block_invoke_0 + 668
3   UIKit   -[UICollectionViewData validateLayoutInRect:] + 1408
4   UIKit   -[UICollectionViewData layoutAttributesForElementsInRect:] + 82
5   UIKit   -[UICollectionView setCollectionViewLayout:animated:] + 1644
6   MyApp   BSCTopnewsCollectionView.m line 52 -[BSCTopnewsCollectionView setupBSCTopnewsCollectionView]
7   MyApp   BSCTopnewsCollectionView.m line 27 -[BSCTopnewsCollectionView setWeakDelegatePointer:]
8   Myapp   BSCFrontPageViewController.m line 550 -[BSCFrontPageViewController collectionView:cellForItemAtIndexPath:]
9   UIKit   -[UICollectionView _createPreparedCellForItemAtIndexPath:withLayoutAttributes:] + 252
10  UIKit   -[UICollectionView _updateVisibleCellsNow:] + 2672
11  UIKit   -[UICollectionView layoutSubviews] + 214
12  UIKit   -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 258
13  QuartzCore  -[CALayer layoutSublayers] + 214
14  QuartzCore  CA::Layer::layout_if_needed(CA::Transaction*) + 460
15  QuartzCore  CA::Layer::layout_and_display_if_needed(CA::Transaction*) + 16
16  QuartzCore  CA::Context::commit_transaction(CA::Transaction*) + 238
17  QuartzCore  CA::Transaction::commit() + 316
18  QuartzCore  CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) + 60
19  CoreFoundation  __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 20
25  UIKit   UIApplicationMain + 1120
26  MyApp   main.m line 16 main 


Exception Type:
    EXC_BAD_ACCESS
Code:
    KERN_INVALID_ADDRESS at 0x158848 

What I'm doing in line 52 in setupBSCTopnewsCollectionView is

BSCInfiniteLayout *infiniteLayout = [[BSCInfiniteLayout alloc] init];    

(line 52) self.collectionView.collectionViewLayout = infiniteLayout;

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Edit: -[BSCFrontPageViewController collectionView:cellForItemAtIndexPath:]

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    if([collectionView isEqual:self.collectionView])
    {
        if(indexPath.row == 0) // Header Cell
        {
            BSCTopnewsCollectionView *cell = [collectionView dequeueReusableCellWithReuseIdentifier:BSCHeaderReuseIdentifier forIndexPath:indexPath];
            cell.dataSource = self;
            cell.weakDelegatePointer = self;

            self.topNewsCollectionView = cell;

            return cell;
        }
        else
        {
            //create normal cells
        }
    }
    else if ([collectionView isEqual:self.topNewsCollectionView.collectionView])
    {
        BSCTopNewsHeaderCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:BSCTopNewsCellReuseIdentifier forIndexPath:indexPath];
        BSCNews *topnews = [self.topNews objectAtIndex:indexPath.row];

        [cell setEntity:topnews];

        return cell;
    }
}

A few clarifications for the method calls there:

- (void)setWeakDelegatePointer:(BSCFrontPageViewController *)weakDelegatePointer
{
    _weakDelegatePointer = weakDelegatePointer;

    [self setupBSCTopnewsCollectionView];
    [self.collectionView reloadData];
}

- (void)setupBSCTopnewsCollectionView
{
    self.collectionView.delegate = self.weakDelegatePointer;
    self.collectionView.dataSource = self.weakDelegatePointer;

    BSCInfiniteLayout *infiniteLayout = [[BSCInfiniteLayout alloc] init];


    infiniteLayout.delegate = self;

    // Setup Layout
    self.collectionView.collectionViewLayout = infiniteLayout;
    self.collectionView.showsHorizontalScrollIndicator = NO;
    self.collectionView.pagingEnabled = YES;

    // Register Cells
    [self.collectionView registerNib:[UINib nibWithNibName:@"BSCTopNewsHeaderCell" bundle:nil] forCellWithReuseIdentifier:BSCTopNewsCellReuseIdentifier];
}

---

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Edit3: The crash only seems to occur in special occasions. If the app was in the background, but still in memory and the user opens it up again. It then checks our API for new data, and if it found something will load them and reload the whole outer collectionView. Thats when the crash occurs.

If the CollectionView is reloaded while the app is running without being in the background in the beginning everything is fine.

---

To make the setup a bit more clear.

Answer 1

Pulling our "Answer" out of the comments.

Sadly none of the answers helped. I ended up refactoring the whole thing and then the problem disappeared. I even had an pretty detailed talk with an apple DTS engineer who also didn't knew what to do. So we just refactored. Sorry :/