Problem statement

Describe: 1) what you have tried

Upgrade spine 4.2 to 4.3, some ui spine assets are no longer available.

2) what you expected,
The component can work correctly, just like in 4.2.

3) what actually happened.
An exception was thrown when playing the animation.

NullReferenceException: Object reference not set to an instance of an object
Spine.Unity.MeshGenerator.AddSubmesh (Spine.Unity.SubmeshInstruction instruction, System.Boolean updateTriangles) (at ./Library/PackageCache/com.esotericsoftware.spine.spine-unity@29e87186b6/Runtime/spine-unity/Mesh Generation/MeshGenerator.cs:558)
Spine.Unity.SkeletonGraphic.FillSingleBufferFromInstructions (Spine.ExposedList`1[T] workingSubmeshInstructions, Spine.Unity.MeshRendererBuffers+SmartMesh currentSmartMesh, System.Boolean updateTriangles) (at ./Library/PackageCache/com.esotericsoftware.spine.spine-unity@29e87186b6/Runtime/spine-unity/Components/SkeletonGraphic.cs:878)
Spine.Unity.SkeletonGraphic.FillBuffersFromSubmeshInstructions (Spine.ExposedList`1[T] workingSubmeshInstructions, Spine.Unity.MeshRendererBuffers+SmartMesh currentSmartMesh, System.Boolean updateTriangles) (at ./Library/PackageCache/com.esotericsoftware.spine.spine-unity@29e87186b6/Runtime/spine-unity/Components/SkeletonGraphic.cs:836)
Spine.Unity.SkeletonGraphic.UpdateBuffersToInstructions (System.Boolean calledFromMainThread) (at ./Library/PackageCache/com.esotericsoftware.spine.spine-unity@29e87186b6/Runtime/spine-unity/Components/SkeletonGraphic.Common.cs:655)
Spine.Unity.SkeletonGraphic.UpdateMesh (System.Boolean calledFromMainThread) (at ./Library/PackageCache/com.esotericsoftware.spine.spine-unity@29e87186b6/Runtime/spine-unity/Components/SkeletonGraphic.Common.cs:625)
Spine.Unity.SkeletonGraphic.LateUpdateImplementation (System.Boolean calledFromMainThread) (at ./Library/PackageCache/com.esotericsoftware.spine.spine-unity@29e87186b6/Runtime/spine-unity/Components/SkeletonGraphic.cs:1437)
Spine.Unity.SkeletonGraphic.LateUpdate () (at ./Library/PackageCache/com.esotericsoftware.spine.spine-unity@29e87186b6/Runtime/spine-unity/Components/SkeletonGraphic.cs:456)

Give step-by-step instructions so we can reproduce the problem, if possible.

spine-assets.zip

68kB

Import the resources in the attachment.
Create SkeletonGraphic in Canvas.
Keep the "allowMultipleCanvasRenderers" option disabled.
Play "animation".

Enabling the option can solve this problem, but I need to change all assets in the game, which is quite a pain.

Runtime information

Tell us your Spine Runtimes version.

Use Spine Runtimes via package manager.

"com.esotericsoftware.spine.spine-csharp": "https://github.com/EsotericSoftware/spine-runtimes.git?path=spine-csharp/src#4.3",
"com.esotericsoftware.spine.spine-unity": "https://github.com/EsotericSoftware/spine-runtimes.git?path=spine-unity/Assets/Spine#4.3",