[ASCollectionNode] Scrolling while performing many updates in ASCollectionNode triggers "Couldn't find 'visible' item at index path" assertion

[kasperwelner]

Hi, I've asked about this a couple of times in the Slack channel but did not really receive any helpful advice. I am not sure whether this is a bug in Texture or not.

I was investigating a bug leading to a SIGABRT from line 71 in ASInternalHelpers.mm
dispatch_async(dispatch_get_main_queue(), block);

After building Texture with Carthage using --configuration Debug I started to get a crash in ASCollectionView.mm on line 1821:
ASDisplayNodeFailAssert(@"Couldn't find 'visible' item at index path %@ in map %@", indexPath, map);

I am pretty confident I'm performing all my datasource and corresponding ASCollectionNode updates correctly.

I have thrown together a project that consistently reproduces the error. It includes all frameworks. AsyncDisplayKit 2.3.3 have been built using Debug configuration.

I am pretty sure the two above issues are linked, but using a Release build of AsyncDisplayKit with the test project, I can't seem to reproduce the first one. However I get it fairly regularly in the App I'm working on. I can't post that code here though.

Link to download project: https://www.dropbox.com/s/96f0403zdq2isdb/ASCollectionNodeCrash.zip?dl=0

NOTE: Scroll around to be sure it crashes!

Project is Swift 4 and needs to be opened in XCode 9, but the error occurred just as frequently before I did the update.

[appleguy]

@kasperwelner thanks a lot for filing this - it's a very high quality report. Apologies that we didn't get to your Slack question - hope you don't encounter any other blockers soon, but let us know if we can help.