Godot scene loading with NodePaths seemingly fails randomly after some time

[hhyyrylainen]

It seems like NodePaths get sometimes loaded as null into C# classes seemingly randomly. The same scenes load correctly hundreds of times.

This has been reported to Godot: godotengine/godot#93083

This likely causes:

• Editor screen fails to load anything randomly #5075
• Save reading can randomly start failing after playing some time #5070

A potential workaround is to switch to:

• Switch all NodePath usages to direct node references #4940

[hhyyrylainen]

Another case:

Starting load of save: auto_save_4.thrivesave
World generation settings: [LAWK: True, Difficulty: hard preset, Life origin: Vent, Seed: 7618708444814157935, Day/night cycle enabled: True, Day length: 180, Include multicellular: True, Easter eggs: True]
USER ERROR: Node not found: "HSplitContainer/PatchDetailsPanel" (relative to "/root/MicrobeStage/PauseMenu/Thriveopedia/MarginContainer/VBoxContainer/HBoxContainer3/MarginContainer/ThriveopediaPatchMapPage").
   at: get_node (scene/main/node.cpp:1651)
USER ERROR: System.NullReferenceException: Object reference not set to an instance of an object.
   at ThriveopediaPatchMapPage.UpdatePlayerPatch(Patch patch) in /home/hhyyrylainen/Projects/Thrive/src/thriveopedia/pages/ThriveopediaPatchMapPage.cs:line 114
   at ThriveopediaPatchMapPage.SetGameForMap() in /home/hhyyrylainen/Projects/Thrive/src/thriveopedia/pages/ThriveopediaPatchMapPage.cs:line 135
   at ThriveopediaPatchMapPage.UpdateCurrentWorldDetails() in /home/hhyyrylainen/Projects/Thrive/src/thriveopedia/pages/ThriveopediaPatchMapPage.cs:line 69
   at Thriveopedia.set_CurrentGame(GameProperties value) in /home/hhyyrylainen/Projects/Thrive/src/thriveopedia/Thriveopedia.cs:line 135
   at PauseMenu.set_GameProperties(GameProperties value) in /home/hhyyrylainen/Projects/Thrive/src/general/PauseMenu.cs:line 111
   at StageBase.SetupStage() in /home/hhyyrylainen/Projects/Thrive/src/general/base_stage/StageBase.cs:line 232
   at CreatureStageBase`2.SetupStage() in /home/hhyyrylainen/Projects/Thrive/src/general/base_stage/CreatureStageBase.cs:line 284
   at MicrobeStage.SetupStage() in /home/hhyyrylainen/Projects/Thrive/src/microbe_stage/MicrobeStage.cs:line 780
   at MicrobeStage._Ready() in /home/hhyyrylainen/Projects/Thrive/src/microbe_stage/MicrobeStage.cs:line 160
   at Godot.Node.InvokeGodotClassMethod(godot_string_name& method, NativeVariantPtrArgs args, godot_variant& ret)
   at StageBase.InvokeGodotClassMethod(godot_string_name& method, NativeVariantPtrArgs args, godot_variant& ret) in /home/hhyyrylainen/Projects/Thrive/Godot.SourceGenerators/Godot.SourceGenerators.ScriptMethodsGenerator/StageBase_ScriptMethods.generated.cs:line 208
   at CreatureStageBase`2.InvokeGodotClassMethod(godot_string_name& method, NativeVariantPtrArgs args, godot_variant& ret) in /home/hhyyrylainen/Projects/Thrive/Godot.SourceGenerators/Godot.SourceGenerators.ScriptMethodsGenerator/CreatureStageBase(Of TPlayer, TSimulation)_ScriptMethods.generated.cs:line 238
   at MicrobeStage.InvokeGodotClassMethod(godot_string_name& method, NativeVariantPtrArgs args, godot_variant& ret) in /home/hhyyrylainen/Projects/Thrive/Godot.SourceGenerators/Godot.SourceGenerators.ScriptMethodsGenerator/MicrobeStage_ScriptMethods.generated.cs:line 368
   at Godot.Bridge.CSharpInstanceBridge.Call(IntPtr godotObjectGCHandle, godot_string_name* method, godot_variant** args, Int32 argCount, godot_variant_call_error* refCallError, godot_variant* ret)
   at: void Godot.NativeInterop.ExceptionUtils.LogException(System.Exception) (:0)
load finished, success: True message: Завантаження завершено elapsed: 00:00:02.8581285

[hhyyrylainen]

This error is probably the same root cause but for something that doesn't use NodePaths (probably):

ERROR: Scene instance is missing.
ERROR: at: (scene/resources/packed_scene.cpp:244)
ERROR: Failed to load Thriveopedia page Museum due to scene instantiate failure