[5.2] Setting a transition in the base layer to the exit node crashes animator window

Hello everyone,

Pretty big problem in the newest 5.2 and it's so simple it baffles me a thing like that could pass QA.

Anyway, here how to reproduce :

1. Create an animator
2. Create a sub state machine
3. Create a transition from this sub state machine to the exit node.
4. Enter the sub state machine.

At this point, the editor triggers null pointers errors every repaint and the animator window doesn't work anymore.You have to open another controller to reset it.

Here the stack trace :

Code (CSharp):

1. NullReferenceException: Object reference not set to an instance of an object
2. UnityEditor.Graphs.AnimationStateMachine.Graph.CreateSelectorEdges (UnityEditor.Animations.AnimatorTransition transition, UnityEditor.Animations.AnimatorStateMachine owner, UnityEditor.Animations.AnimatorStateMachine sourceStateMachine) (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/AnimationStateMachine/Graph.cs:125)
3. UnityEditor.Graphs.AnimationStateMachine.Graph.CreateEdges () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/AnimationStateMachine/Graph.cs:241)
4. UnityEditor.Graphs.AnimationStateMachine.Graph.BuildGraphFromStateMachine (UnityEditor.Animations.AnimatorStateMachine stateMachine) (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/AnimationStateMachine/Graph.cs:76)
5. UnityEditor.Graphs.AnimationStateMachine.Graph.RebuildGraph () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/AnimationStateMachine/Graph.cs:57)
6. UnityEditor.Graphs.AnimationStateMachine.GraphGUI.OnGraphGUI () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/AnimationStateMachine/GraphGUI.cs:268)
7. UnityEditor.Graphs.AnimatorControllerTool.StateMachineView (Rect position) (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Animation/AnimatorControllerTool.cs:943)
8. UnityEditor.Graphs.AnimatorControllerTool.OnGUIGraph (Rect paneRect) (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Animation/AnimatorControllerTool.cs:876)
9. UnityEditor.Graphs.AnimatorControllerTool.OnGUI () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Animation/AnimatorControllerTool.cs:833)
10. System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:222)

I've tested several configurations, it does not matter what's before or inside the sub state machine, just transitioning it to the exit node is the culprit here.
You don't even need actual animations in your animator controller to cause the bug (I've tested with and without, the problem happens everytime).

Bug case #726767.

 

I have the same problem. I found that it was reported in the beta - 5.2.0b6 (not by me):
http://issuetracker.unity3d.com/iss...sitioning-from-sub-state-machine-to-exit-node

It says fixed in Unity 5.2.1. This is realy bad, because we either have to wait for 5.2.1 to be released ( who knows when ) or revert to Unity 5.1.3. The thing is that 5.2 "fixed" some other Mecanim bugs and we are now stuck with completеly unusable version.

 

In response to my bug, Unity QA just informed me that this should be fixed in 5.2.1

 

I just came across this issue in 2018.3.7f1. The only way I got it to work again is to revert the animation controller back to the previous version and redo all the new changes.