Assertion failed: Ret->IsA(T::StaticClass())

Medie · November 3, 2023, 10:15pm

I get this assertion error after i created a C++ class inheriting from UObject. There’s nothing going on it’s just the boilerplate.

The assertion failed is coming from Engine\Source\Runtime\CoreUObject\Public\UObject\Class.h] [Line: 3295].

This crash log goes into data races and threading which i know nothing about as a newbie programmer.

Would love for someone to explain to me what’s going on in this log and if it’s even possible for me to fix this issue using the prebuilt UE version from the Unreal Launcher.

[2023.11.03-22.02.41:618][576]LogOutputDevice: Error: === Handled ensure: === [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: Ensure condition failed: LocalState.GetWriterThreadId() == CurrentThreadId [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Misc\MTAccessDetector.h] [Line: 589] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: Data race detected: acquiring write access on thread 19732 concurrently with 1 writers on thread 13464: [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: Current thread 19732 callstack: [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0aeca8e1 UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0af2c86c UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0ae85ca0 UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0ae64ee4 UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0ae8573f UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0aeffc7b UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e891098 UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e891320 UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e8910de UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb56fbf568 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb573f4e22 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb573e8657 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffc14f47614 KERNEL32.DLL!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffc157826a1 ntdll.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: Writer thread 13464 callstack: [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb57244235 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb572d06b2 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb56fff24a UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb56fd4757 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb56febcad UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb570681b8 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb57069d93 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb570698be UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb57243b0e UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb51277ee4 UnrealEditor-Engine.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb5127ae5d UnrealEditor-Engine.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb5127b343 UnrealEditor-Engine.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb43da00b8 UnrealEditor-BlueprintGraph.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb43f02e7e UnrealEditor-BlueprintGraph.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e891098 UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e891320 UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e8910de UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb56fbf568 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:618][576]LogOutputDevice: Error: [Callstack] 0x00007ffb573f4e22 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffb573e8657 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffc14f47614 KERNEL32.DLL!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: Stack: [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0ae85ca0 UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0ae64ee4 UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0ae8573f UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0aeffc7b UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e891098 UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e891320 UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e8910de UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffb56fbf568 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffb573f4e22 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffb573e8657 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffc14f47614 KERNEL32.DLL!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [Callstack] 0x00007ffc157826a1 ntdll.dll!UnknownFunction [] [2023.11.03-22.02.41:619][576]LogOutputDevice: Error: [2023.11.03-22.02.41:629][576]LogStats: SubmitErrorReport - 0.000 s [2023.11.03-22.02.45:186][576]LogStats: SendNewReport - 3.558 s [2023.11.03-22.02.45:186][576]LogStats: FDebug::EnsureFailed - 3.592 s [2023.11.03-22.02.45:264][576]LogStats: FPlatformStackWalk::StackWalkAndDump - 0.022 s [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: === Handled ensure: === [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: Ensure condition failed: LocalState == PrevState [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Misc\MTAccessDetector.h] [Line: 602] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: Data race detected: other thread(s) activity during acquiring write access on thread 19732: 0 -> 0 readers, 1 -> 0 writers on thread 13464 -> 4294967295: [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: Current thread 19732 callstack: [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0aeca8e1 UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0af2c9ea UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0ae85cfb UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0ae64ee4 UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0ae8573f UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0aeffc7b UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e891098 UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e891320 UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e8910de UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffb56fbf568 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffb573f4e22 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffb573e8657 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffc14f47614 KERNEL32.DLL!UnknownFunction [] [2023.11.03-22.02.45:264][576]LogOutputDevice: Error: [Callstack] 0x00007ffc157826a1 ntdll.dll!UnknownFunction [] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: Writer thread 4294967295 callstack: [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [none] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: Stack: [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0ae85cfb UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0ae64ee4 UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0ae8573f UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [Callstack] 0x00007ffb0aeffc7b UnrealEditor-USDStage.dll!UnknownFunction [] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e891098 UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e891320 UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [Callstack] 0x00007ffb4e8910de UnrealEditor-UnrealEd.dll!UnknownFunction [] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [Callstack] 0x00007ffb56fbf568 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [Callstack] 0x00007ffb573f4e22 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [Callstack] 0x00007ffb573e8657 UnrealEditor-Core.dll!UnknownFunction [] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [Callstack] 0x00007ffc14f47614 KERNEL32.DLL!UnknownFunction [] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [Callstack] 0x00007ffc157826a1 ntdll.dll!UnknownFunction [] [2023.11.03-22.02.45:265][576]LogOutputDevice: Error: [2023.11.03-22.02.45:273][576]LogStats: SubmitErrorReport - 0.000 s [2023.11.03-22.02.53:160][576]LogStats: SendNewReport - 7.887 s [2023.11.03-22.02.53:160][576]LogStats: FDebug::EnsureFailed - 7.918 s [2023.11.03-22.02.53:415][576]LogUObjectHash: Compacting FUObjectHashTables data took 2.22ms [2023.11.03-22.02.53:797][576]LogSlate: Window 'Vicious - Unreal Editor' being destroyed [2023.11.03-22.02.53:912][576]LogWorld: UWorld::CleanupWorld for World_1, bSessionEnded=true, bCleanupResources=true [2023.11.03-22.02.53:913][576]MassEntity: New page: MassEntity [2023.11.03-22.02.53:913][576]LogSlate: InvalidateAllWidgets triggered. All widgets were invalidated [2023.11.03-22.02.54:074][576]LogActorComponent: UnregisterComponent: (/Engine/Transient.EditorFloorComp) Not registered. Aborting. [2023.11.03-22.02.54:074][576]LogWorld: UWorld::CleanupWorld for World_2, bSessionEnded=true, bCleanupResources=true [2023.11.03-22.02.54:074][576]MassEntity: New page: MassEntity [2023.11.03-22.02.54:074][576]LogSlate: InvalidateAllWidgets triggered. All widgets were invalidated [2023.11.03-22.02.54:428][576]LogOutputDevice: Warning: Script Stack (0 frames) : [2023.11.03-22.02.54:434][576]LogWindows: Error: appError called: Assertion failed: Ret->IsA(T::StaticClass()) [File:D:\build++UE5\Sync\Engine\Source\Runtime\CoreUObject\Public\UObject\Class.h] [Line: 3295] [2023.11.03-22.02.54:434][576]LogWindows: Windows GetLastError: The operation completed successfully. (0)

SteveRambo · November 3, 2023, 10:37pm

When is this occurring? (startup, build, cook, etc.)

Medie · November 3, 2023, 10:49pm

happens only when compiling it using live coding in the editor.

Medie · November 3, 2023, 10:50pm

Didn’t reply properly to you my bad.

SteveRambo · November 3, 2023, 11:13pm

If you close the editor and try building the solution(clean first then build), do you still get this issue?

Medie · November 4, 2023, 6:57am

Yea it still happens after both rebuilding and building. I’m assuming i’ve made a property spcifier mistake somewhere but i don’t get an error for that. Something to note is that the automation tool and build graph always fail when building. Don’t know why the error is kinda vague.

4>B:\UnrealEngine_M.2\UE_5.3\Engine\Source\Programs\AutomationTool\Scripts\CheckForHacks.cs(87,26,87,45): error CA2017: Number of parameters supplied in the logging message template do not match the number of named placeholders (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2017)

5>B:\UnrealEngine_M.2\UE_5.3\Engine\Source\Programs\AutomationTool\BuildGraph\BgScriptReader.cs(1640,37,1640,42): error CS8604: Possible null reference argument for parameter 'other' in 'void HashSet.UnionWith(IEnumerable other)'.