Deleting IK target results in engine crash

[sashkent3]

Steps to reproduce

1. Add go.delete("ik-target") immediately after:
   

   extension-spine/examples/basic_animation/basic_animation.script

   Line 50 in 069bf18

   spine.set_ik_target(self.url, "aim-ik", "ik-target")

2. Launch the "Basic Animation" example
3. Observe the engine crash:

INFO:CRASH: Successfully wrote Crashdump to file: /home/sasha/.local/share/Defold/_crash
ERROR:CRASH: CALL STACK:

ERROR:CRASH: /home/sasha/Documents/extension-spine-clean/build/x86_64-linux/dmengine(+0x5030e7) [0x561976ba10e7]
ERROR:CRASH: /usr/lib/libc.so.6(+0x3e8f0) [0x7f5591c3e8f0]
ERROR:CRASH: /home/sasha/Documents/extension-spine-clean/build/x86_64-linux/dmengine(+0x1e8a8b) [0x561976886a8b]
ERROR:CRASH: /home/sasha/Documents/extension-spine-clean/build/x86_64-linux/dmengine(+0x6ce6c5) [0x561976d6c6c5]
ERROR:CRASH: /home/sasha/Documents/extension-spine-clean/build/x86_64-linux/dmengine(+0x1ebb9e) [0x561976889b9e]
ERROR:CRASH: /home/sasha/Documents/extension-spine-clean/build/x86_64-linux/dmengine(+0x1e7fd4) [0x561976885fd4]
ERROR:CRASH: /home/sasha/Documents/extension-spine-clean/build/x86_64-linux/dmengine(+0x21baaa) [0x5619768b9aaa]
ERROR:CRASH: /home/sasha/Documents/extension-spine-clean/build/x86_64-linux/dmengine(+0x1ebb9e) [0x561976889b9e]
ERROR:CRASH: /home/sasha/Documents/extension-spine-clean/build/x86_64-linux/dmengine(+0x1e7fd4) [0x561976885fd4]
ERROR:CRASH: /home/sasha/Documents/extension-spine-clean/build/x86_64-linux/dmengine(+0x1c50f5) [0x5619768630f5]
ERROR:CRASH: /home/sasha/Documents/extension-spine-clean/build/x86_64-linux/dmengine(+0x1c5885) [0x561976863885]
ERROR:CRASH: /home/sasha/Documents/extension-spine-clean/build/x86_64-linux/dmengine(+0x1c6a26) [0x561976864a26]
ERROR:CRASH: /home/sasha/Documents/extension-spine-clean/build/x86_64-linux/dmengine(+0x1c0e71) [0x56197685ee71]
ERROR:CRASH: /usr/lib/libc.so.6(+0x27741) [0x7f5591c27741]
ERROR:CRASH: /usr/lib/libc.so.6(__libc_start_main+0x89) [0x7f5591c27879]
ERROR:CRASH: /home/sasha/Documents/extension-spine-clean/build/x86_64-linux/dmengine(+0x1c0c45) [0x56197685ec45]
ERROR:CRASH: 

System info

• Defold: 1.12.4-stable (defold/defold@402218d)
• extension-spine: 4.6.1 (069bf18)
• Platform: linux-x86_64

[AGulev]

VM Region Info: 0x1870 is not in any region.  Bytes before following region: 4374161296
      REGION TYPE                    START - END         [ VSIZE] PRT/MAX SHRMOD  REGION DETAIL
      UNUSED SPACE AT START
--->  
      __TEXT                      104b88000-104fac000    [ 4240K] r-x/r-x SM=COW  /Users/USER/*/dmengine

Thread 0 Crashed:: engine_main Dispatch queue: com.apple.main-thread
0   dmengine                      	       0x104c9ed00 dmArray<Vectormath::Aos::Matrix4>::Size() const + 0 (array.h:456) [inlined]
1   dmengine                      	       0x104c9ed00 dmArray<Vectormath::Aos::Matrix4>::operator[](unsigned int) + 0 (array.h:486) [inlined]
2   dmengine                      	       0x104c9ed00 dmGameObject::GetWorldPosition(dmGameObject::Instance*) + 12 (gameobject.cpp:3243)
3   dmengine                      	       0x104c63468 dmSpine::ApplyIKTargets(dmSpine::SpineModelComponent*) + 688 (comp_spine_model.cpp:801) [inlined]
4   dmengine                      	       0x104c63468 dmSpine::CompSpineModelUpdate(dmGameObject::ComponentsUpdateParams const&, dmGameObject::ComponentsUpdateResult&) + 1220 (comp_spine_model.cpp:840)
5   dmengine                      	       0x104ca102c dmGameObject::UpdateComponentFunction(dmGameObject::Collection*, unsigned int, dmGameObject::UpdateFunctionType, dmGameObject::ComponentsUpdateParams&) + 220 (gameobject.cpp:2725)
6   dmengine                      	       0x104c9e4d4 dmGameObject::Update(dmGameObject::Collection*, dmGameObject::UpdateContext const*) + 476 (gameobject.cpp:2848) [inlined]
7   dmengine                      	       0x104c9e4d4 dmGameObject::Update(dmGameObject::CollectionHandle*, dmGameObject::UpdateContext const*) + 508 (gameobject.cpp:2864)
8   dmengine                      	       0x104ce8778 dmGameSystem::CompCollectionProxyUpdate(dmGameObject::ComponentsUpdateParams const&, dmGameObject::ComponentsUpdateResult&) + 448 (comp_collection_proxy.cpp:375)
9   dmengine                      	       0x104ca102c dmGameObject::UpdateComponentFunction(dmGameObject::Collection*, unsigned int, dmGameObject::UpdateFunctionType, dmGameObject::ComponentsUpdateParams&) + 220 (gameobject.cpp:2725)
10  dmengine                      	       0x104c9e4d4 dmGameObject::Update(dmGameObject::Collection*, dmGameObject::UpdateContext const*) + 476 (gameobject.cpp:2848) [inlined]
11  dmengine                      	       0x104c9e4d4 dmGameObject::Update(dmGameObject::CollectionHandle*, dmGameObject::UpdateContext const*) + 508 (gameobject.cpp:2864)
12  dmengine                      	       0x104c72c6c dmEngine::StepFrame(dmEngine::Engine*, float) + 808 (engine.cpp:2114) [inlined]
13  dmengine                      	       0x104c72c6c dmEngine::Step(dmEngine::Engine*) + 1568 (engine.cpp:2314)
14  dmengine                      	       0x104c73208 dmEngineUpdate(dmEngine::Engine*) + 28 (engine.cpp:2687)
15  dmengine                      	       0x104c73d50 dmEngine::RunLoop(dmEngine::RunLoopParams const*) + 92 (engine_loop.cpp:86)
16  dmengine                      	       0x104c73cdc EngineMain(int, char**) + 80 (engine_main.cpp:57) [inlined]
17  dmengine                      	       0x104c73cdc engine_main(int, char**) + 104 (engine_main.cpp:157)
18  dyld                          	       0x180c5fe00 start + 6992

Thread 1:

[AGulev]

The same in gui:

Triggered by Thread: 0  engine_main, Dispatch Queue: com.apple.main-thread

Exception Type:    EXC_CRASH (SIGABRT)
Exception Codes:   0x0000000000000000, 0x0000000000000000


Thread 0 Crashed:: engine_main Dispatch queue: com.apple.main-thread
0   libsystem_kernel.dylib        	       0x180fe25e8 __pthread_kill + 8
1   libsystem_pthread.dylib       	       0x18101d8d8 pthread_kill + 296
2   libsystem_c.dylib             	       0x180f24644 abort + 148
3   libsystem_c.dylib             	       0x180f238a0 __assert_rtn + 284
4   dmengine                      	       0x104541740 <deduplicated_symbol> + 12
5   dmengine                      	       0x1044b7cec dmGui::GetNode(dmGui::Scene*, unsigned int) + 8 (gui.cpp:301) [inlined]
6   dmengine                      	       0x1044b7cec dmGui::GetNodeProperty(dmGui::Scene*, unsigned int, dmGui::Property) + 116 (gui.cpp:3366)
7   dmengine                      	       0x1042ad4a8 dmSpine::ApplyIKTargets(dmSpine::InternalGuiNode*) + 116 (gui_node_spine.cpp:1173) [inlined]
8   dmengine                      	       0x1042ad4a8 dmSpine::GuiUpdate(dmGameSystem::CustomNodeCtx const*, float) + 344 (gui_node_spine.cpp:1243)
9   dmengine                      	       0x1043322a8 dmGameSystem::UpdateCustomNodeCallback(void*, dmGui::Scene*, unsigned int, unsigned int, void*, float) + 132 (comp_gui.cpp:2943)
10  dmengine                      	       0x1044b5c04 dmGui::UpdateScene(dmGui::Scene*, float) + 384 (gui.cpp:2577)
11  dmengine                      	       0x10433119c dmGameSystem::CompGuiUpdate(dmGameObject::ComponentsUpdateParams const&, dmGameObject::ComponentsUpdateResult&) + 204 (comp_gui.cpp:2972)
12  dmengine                      	       0x1042e5124 dmGameObject::UpdateComponentFunction(dmGameObject::Collection*, unsigned int, dmGameObject::UpdateFunctionType, dmGameObject::ComponentsUpdateParams&) + 220 (gameobject.cpp:2725)
13  dmengine                      	       0x1042e25cc dmGameObject::Update(dmGameObject::Collection*, dmGameObject::UpdateContext const*) + 476 (gameobject.cpp:2848) [inlined]
14  dmengine                      	       0x1042e25cc dmGameObject::Update(dmGameObject::CollectionHandle*, dmGameObject::UpdateContext const*) + 508 (gameobject.cpp:2864)
15  dmengine                      	       0x10432c870 dmGameSystem::CompCollectionProxyUpdate(dmGameObject::ComponentsUpdateParams const&, dmGameObject::ComponentsUpdateResult&) + 448 (comp_collection_proxy.cpp:375)
16  dmengine                      	       0x1042e5124 dmGameObject::UpdateComponentFunction(dmGameObject::Collection*, unsigned int, dmGameObject::UpdateFunctionType, dmGameObject::ComponentsUpdateParams&) + 220 (gameobject.cpp:2725)
17  dmengine                      	       0x1042e25cc dmGameObject::Update(dmGameObject::Collection*, dmGameObject::UpdateContext const*) + 476 (gameobject.cpp:2848) [inlined]
18  dmengine                      	       0x1042e25cc dmGameObject::Update(dmGameObject::CollectionHandle*, dmGameObject::UpdateContext const*) + 508 (gameobject.cpp:2864)
19  dmengine                      	       0x1042b6d84 dmEngine::StepFrame(dmEngine::Engine*, float) + 808 (engine.cpp:2114) [inlined]
20  dmengine                      	       0x1042b6d84 dmEngine::Step(dmEngine::Engine*) + 1568 (engine.cpp:2314)
21  dmengine                      	       0x1042b7320 dmEngineUpdate(dmEngine::Engine*) + 28 (engine.cpp:2687)
22  dmengine                      	       0x1042b7e68 dmEngine::RunLoop(dmEngine::RunLoopParams const*) + 92 (engine_loop.cpp:86)
23  dmengine                      	       0x1042b7df4 EngineMain(int, char**) + 80 (engine_main.cpp:57) [inlined]
24  dmengine                      	       0x1042b7df4 engine_main(int, char**) + 104 (engine_main.cpp:157)
25  dyld                          	       0x180c5fe00 start + 6992