Unreal Engine Issues and Bug Tracker (UE-65669)

Description

Placing a FunctionalTest Blueprint into a level that contains a landscape component and a sub-level that also contains a landscape component results in a crash when PIE is started. This only occurs in 4.20+ if the project is being upgraded from 4.19 or earlier. The crash does not occur if the project is created in 4.20, or if the FunctionalTest Blueprint is not present in the level. The crash also does not occur when upgrading a project from 4.18 to 4.19.

This appears to be due to the LandscapeComponent not having a MobileCombinationMaterialInstance set. The Editor attempts to create this, which ends up resulting in an assert.

REGRESSION:
Yes

Steps to Reproduce

Download the attached project (created in 4.19.2).
Associate the project with any Engine version 4.20 or higher.
Build the project in Visual Studio.
Open the project in the Editor.
Start PIE.

RESULT:
The Editor crashes with the error Cannot call UnrealScript (BP_SampleTest_C /Game/VehicleAdvCPP/Maps/UEDPIE_0_VehicleAdvExampleMap.VehicleAdvExampleMap:PersistentLevel.BP_SampleTest_2 - Function /Script/FunctionalTesting.FunctionalTest:DebugGatherRelevantActors) while PostLoading objects

EXPECTED:
The Editor starts PIE successfully.

Callstack

Assertion failed: !FUObjectThreadContext::Get().IsRoutingPostLoad [File:D:\Main-Builds\Stream\Engine\Source\Runtime\CoreUObject\Private\UObject\ScriptCore.cpp] [Line: 1316] Cannot call UnrealScript (BP_SampleTest_C /Game/VehicleAdvCPP/Maps/UEDPIE_0_VehicleAdvExampleMap.VehicleAdvExampleMap:PersistentLevel.BP_SampleTest_2 - Function /Script/FunctionalTesting.FunctionalTest:DebugGatherRelevantActors) while PostLoading objects

UE4Editor_Core!FDebug::AssertFailed() [d:\main-builds\stream\engine\source\runtime\core\private\misc\assertionmacros.cpp:422]
UE4Editor_CoreUObject!UObject::ProcessEvent() [d:\main-builds\stream\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1316]
UE4Editor_Engine!AActor::ProcessEvent() [d:\main-builds\stream\engine\source\runtime\engine\private\actor.cpp:713]
UE4Editor_FunctionalTesting!AFunctionalTest::DebugGatherRelevantActors() [d:\main-builds\stream\engine\intermediate\build\win64\ue4editor\inc\functionaltesting\functionaltest.gen.cpp:908]
UE4Editor_FunctionalTesting!AFunctionalTest::GatherRelevantActors() [d:\main-builds\stream\engine\source\developer\functionaltesting\private\functionaltest.cpp:448]
UE4Editor_FunctionalTesting!UFuncTestRenderingComponent::CalcBounds() [d:\main-builds\stream\engine\source\developer\functionaltesting\private\functestrenderingcomponent.cpp:111]
UE4Editor_Engine!USceneComponent::UpdateBounds() [d:\main-builds\stream\engine\source\runtime\engine\private\components\scenecomponent.cpp:1183]
UE4Editor_Engine!UPrimitiveComponent::UpdateBounds() [d:\main-builds\stream\engine\source\runtime\engine\private\components\primitivecomponent.cpp:3107]
UE4Editor_Engine!UPrimitiveComponent::CreateRenderState_Concurrent() [d:\main-builds\stream\engine\source\runtime\engine\private\components\primitivecomponent.cpp:513]
UE4Editor_Engine!TIndirectArray<FComponentRecreateRenderStateContext,FDefaultAllocator>::Empty() [d:\main-builds\stream\engine\source\runtime\core\public\containers\indirectarray.h:337]
UE4Editor_Engine!FGlobalComponentRecreateRenderStateContext::~FGlobalComponentRecreateRenderStateContext() [d:\main-builds\stream\engine\source\runtime\engine\private\components\actorcomponent.cpp:139]
UE4Editor_Engine!FMaterialUpdateContext::~FMaterialUpdateContext() [d:\main-builds\stream\engine\source\runtime\engine\private\materials\materialshared.cpp:2696]
UE4Editor_Engine!UMaterialInstance::UpdateStaticPermutation() [d:\main-builds\stream\engine\source\runtime\engine\private\materials\materialinstance.cpp:3539]
UE4Editor_Landscape!ULandscapeComponent::GetCombinationMaterial() [d:\main-builds\stream\engine\source\runtime\landscape\private\landscapeedit.cpp:272]
UE4Editor_Landscape!ULandscapeComponent::UpdateMaterialInstances_Internal() [d:\main-builds\stream\engine\source\runtime\landscape\private\landscapeedit.cpp:329]
UE4Editor_Landscape!ULandscapeComponent::UpdateMaterialInstances() [d:\main-builds\stream\engine\source\runtime\landscape\private\landscapeedit.cpp:427]
UE4Editor_Landscape!ULandscapeComponent::PostLoad() [d:\main-builds\stream\engine\source\runtime\landscape\private\landscape.cpp:762]
UE4Editor_CoreUObject!UObject::ConditionalPostLoad() [d:\main-builds\stream\engine\source\runtime\coreuobject\private\uobject\obj.cpp:1031]
UE4Editor_CoreUObject!FAsyncPackage::PostLoadObjects() [d:\main-builds\stream\engine\source\runtime\coreuobject\private\serialization\asyncloading.cpp:6512]
UE4Editor_CoreUObject!FAsyncPackage::TickAsyncPackage() [d:\main-builds\stream\engine\source\runtime\coreuobject\private\serialization\asyncloading.cpp:5728]
UE4Editor_CoreUObject!FAsyncLoadingThread::ProcessAsyncLoading() [d:\main-builds\stream\engine\source\runtime\coreuobject\private\serialization\asyncloading.cpp:4598]
UE4Editor_CoreUObject!FAsyncLoadingThread::TickAsyncThread() [d:\main-builds\stream\engine\source\runtime\coreuobject\private\serialization\asyncloading.cpp:5157]
UE4Editor_CoreUObject!FAsyncLoadingThread::TickAsyncLoading() [d:\main-builds\stream\engine\source\runtime\coreuobject\private\serialization\asyncloading.cpp:4863]
UE4Editor_CoreUObject!ProcessAsyncLoading() [d:\main-builds\stream\engine\source\runtime\coreuobject\private\serialization\asyncloading.cpp:7190]
UE4Editor_CoreUObject!StaticTick() [d:\main-builds\stream\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:525]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\main-builds\stream\engine\source\editor\unrealed\private\editorengine.cpp:1371]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\main-builds\stream\engine\source\editor\unrealed\private\unrealedengine.cpp:403]
UE4Editor!FEngineLoop::Tick() [d:\main-builds\stream\engine\source\runtime\launch\private\launchengineloop.cpp:3694]
UE4Editor!GuardedMain() [d:\main-builds\stream\engine\source\runtime\launch\private\launch.cpp:174]
UE4Editor!GuardedMainWrapper() [d:\main-builds\stream\engine\source\runtime\launch\private\windows\launchwindows.cpp:145]
UE4Editor!WinMain() [d:\main-builds\stream\engine\source\runtime\launch\private\windows\launchwindows.cpp:276]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
kernel32
ntdll

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Fixed

Component	UE - LD & Modeling - Terrain - Landscape
Affects Versions	4.21, 4.22, 4.20.3
Target Fix	4.22

Fix Commit	4732979
Main Commit	4837001
Release Commit	4862694

Created	Oct 23, 2018
Resolved	Jan 16, 2019
Updated	Feb 12, 2019

View Jira Issue

UE-65669

Crash occurs when starting PIE on a level containing a FunctionalTest Blueprint and a sub-level with a landscape component in both levels

Crash occurs when starting PIE on a level containing a FunctionalTest Blueprint and a sub-level with a landscape component in both levels

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