Assertion in _UIDragSnappingFeedbackGenerator.userInteractionStarted at UIDragSession start

Originator:steipete
Number:rdar://42154922 Date Originated:13-Jul-2018 09:07 AM
Status:Open Resolved:
Product:iOS + SDK Product Version:12 beta 3
Classification:Crash/Hang/Data Loss Reproducible:Rarely
 
Summary:
This is a duplicate of radar #42139082

We're testing Drag & Drop capabilities in our application, and we've noticed a rare crash that's not easily reproducible:

Here's the crash log:

```
*** Assertion failure in -[_UIDragSnappingFeedbackGenerator userInteractionStarted], /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKitCore/UIKit-3698.79.2/_UIDragFeedbackGenerator.m:175
2018-07-12 14:42:51.323435-0500 Viewer[10264:809379] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '<_UIDragSnappingFeedbackGenerator: 0x2811dcfa0: prepared=1> is already being interacted with'
```

We've seen this crash occur when the drag "lift" animation is just completed on a UICollectionView, and the user starts dragging. There are no other factors that we've identified as related to the crash occurring.


Steps to Reproduce:
Start a drag session by long pressing an item in a collection view.

Expected Results:
The drag session is started correctly, and no crashes are experienced.

Actual Results:
Sometimes, with no clear reason, an exception is thrown from _UIDragSnappingFeedbackGenerator.userInteractionStarted and the app is terminated.

Version:
12 beta 3

Notes:

Comments


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