NullReferenceException on IsPlayingAndNotEnding

[dots-alberto-uriarte]

Environment

• Animancer Version Number: 7.3
• Animancer Pro or Lite: Pro
• Unity Version: 2019.4.35
• Platform: iOS/Android

Description

NullReferenceException: Object reference not set to an instance of an object.
  at Animancer.AnimancerState.IsPlayingAndNotEnding () [0x00000] in <00000000000000000000000000000000>:0 
  at Cysharp.Threading.Tasks.EnumeratorAsyncExtensions+EnumeratorPromise+<ConsumeEnumerator>d__19.MoveNext () [0x00000] in <00000000000000000000000000000000>:0 
  at Cysharp.Threading.Tasks.EnumeratorAsyncExtensions+EnumeratorPromise.MoveNext () [0x00000] in <00000000000000000000000000000000>:0 
  at Cysharp.Threading.Tasks.Internal.PlayerLoopRunner.RunCore () [0x00000] in <00000000000000000000000000000000>:0 
  at UnityEngine.LowLevel.PlayerLoopSystem+UpdateFunction.Invoke () [0x00000] in <00000000000000000000000000000000>:0 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <00000000000000000000000000000000>:0 
  at Cysharp.Threading.Tasks.CompilerServices.AsyncUniTask`1+<>c[TStateMachine].<.cctor>b__12_0 () [0<…>

The exception only appears on device, not on Editor. But on editor we noticed that if we await a Play(clip) on the same frame where we destroy the GameObject of the clip, the AnimancerState.IsPlayingAndNotEnding always returns true (which produce a "Task" leak).

Reproduction

I don't have an example scene to replicate the problem. But something similar to this would generate the problem:

public class AnimancerAsyncExample : MonoBehaviour
{
    [SerializeField] private AnimationClip _clip;
    [SerializeField] private int _animationLayer = 0;
    [SerializeField] private bool _isAdditive = false;
    [SerializeField] private AnimancerComponent _animancerComponent;

    private void OnDestroy()
    {
        AnimationOutAsync().Forget();
    }

    private async UniTaskVoid AnimationOutAsync()
    {
        _animancerComponent.Layers.SetAdditive(_animationLayer, _isAdditive);
        Debug.LogWarning("[Animancer] Animation out START");
        await _animancerComponent.Layers[_animationLayer].Play(_clip);
        Debug.LogWarning("[Animancer] Animation out END");
    }
}

Now destroying the object will cause a Task leak and "[Animancer] Animation out END" message never appears in the console.

Solution

At AnimancerState.IsPlayingAndNotEnding method add this early condition exit

if (!_Playable.IsValid())
{
    return false;
}

[KybernetikGames]

I agree that having IsPlayingAndNotEnding check _Playable.IsValid is reasonable so I've added it for the next version.

[KybernetikGames]

Animancer v7.4 is now available with this fix.