Unreal Engine Issues and Bug Tracker (UE-39323)

Description

A crash is occurring on project load when attempting to use GetParentActor and cast that to a Parent class that contains a child actor component inside of that child actor component's blueprint.

This did not occur in 4.13.2, and as a result, is a regression. This was reproduced in 4.14.0 CL# 3195953 and 4.15 Main CL# 3205566.

Steps to Reproduce

Open the editor
Create 2 Actor blueprint's "Parent" and "Child"
In Parent, add a child actor component and set it's class to Child
Compile & Save Parent
In Child, GetParentActor->Cast to Parent on BeginPlay
Compile & Save Child
Place Parent in the level
Save All & Close project
Re-open project

Result: Project crashes on load

Callstack

Fatal error: [Link Removed] [Line: 11] Cast of LinkerPlaceholderExportObject /Game/FirstPersonBP/Blueprints/Parent.Parent_C:ChildActor_GEN_VARIABLE.ChildActor_GEN_VARIABLE_Child_C_CAT to Actor failed

UE4Editor_CoreUObject!CastLogError() [casts.cpp:12]
UE4Editor_Engine!CastChecked<AActor,UObject>() [casts.h:203]
UE4Editor_Engine!UChildActorComponent::Serialize() [childactorcomponent.cpp:91]
UE4Editor_CoreUObject!FLinkerLoad::Preload() [linkerload.cpp:3414]
UE4Editor_CoreUObject!FLinkerLoad::CreateExportAndPreload() [linkerload.cpp:2890]
UE4Editor_CoreUObject!FLinkerLoad::LoadAllObjects() [linkerload.cpp:3023]
UE4Editor_CoreUObject!LoadPackageInternalInner() [uobjectglobals.cpp:1271]
UE4Editor_CoreUObject!LoadPackageInternal() [uobjectglobals.cpp:1423]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImportInner() [linkerload.cpp:2561]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImport() [linkerload.cpp:2327]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImportInner() [linkerload.cpp:2609]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImport() [linkerload.cpp:2327]
UE4Editor_CoreUObject!FLinkerLoad::CreateImport() [linkerload.cpp:4257]
UE4Editor_CoreUObject!FLinkerLoad::ResolveDependencyPlaceholder() [blueprintsupport.cpp:1090]
UE4Editor_CoreUObject!FLinkerLoad::ResolveDeferredDependencies() [blueprintsupport.cpp:892]
UE4Editor_CoreUObject!FLinkerLoad::ResolveAllImports() [blueprintsupport.cpp:1181]
UE4Editor_CoreUObject!FLinkerLoad::FinalizeBlueprint() [blueprintsupport.cpp:1284]
UE4Editor_CoreUObject!FLinkerLoad::Preload() [linkerload.cpp:3461]
UE4Editor_CoreUObject!FLinkerLoad::CreateExport() [linkerload.cpp:4111]
UE4Editor_CoreUObject!FLinkerLoad::IndexToObject() [linkerload.cpp:4334]
UE4Editor_CoreUObject!FLinkerLoad::CreateExport() [linkerload.cpp:3807]
UE4Editor_CoreUObject!FLinkerLoad::CreateExportAndPreload() [linkerload.cpp:2884]
UE4Editor_CoreUObject!FLinkerLoad::LoadAllObjects() [linkerload.cpp:3023]
UE4Editor_CoreUObject!LoadPackageInternalInner() [uobjectglobals.cpp:1271]
UE4Editor_CoreUObject!LoadPackageInternal() [uobjectglobals.cpp:1423]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImportInner() [linkerload.cpp:2561]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImport() [linkerload.cpp:2327]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImportInner() [linkerload.cpp:2609]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImport() [linkerload.cpp:2327]
UE4Editor_CoreUObject!FLinkerLoad::CreateImport() [linkerload.cpp:4257]
UE4Editor_CoreUObject!FLinkerLoad::ResolveDependencyPlaceholder() [blueprintsupport.cpp:1090]
UE4Editor_CoreUObject!FLinkerLoad::ResolveDeferredDependencies() [blueprintsupport.cpp:950]
UE4Editor_CoreUObject!FLinkerLoad::Preload() [linkerload.cpp:3461]
UE4Editor_CoreUObject!FLinkerLoad::CreateExport() [linkerload.cpp:4111]
UE4Editor_CoreUObject!FLinkerLoad::IndexToObject() [linkerload.cpp:4334]
UE4Editor_CoreUObject!FLinkerLoad::CreateExport() [linkerload.cpp:3807]
UE4Editor_CoreUObject!FLinkerLoad::CreateExportAndPreload() [linkerload.cpp:2884]
UE4Editor_CoreUObject!FLinkerLoad::LoadAllObjects() [linkerload.cpp:3023]
UE4Editor_CoreUObject!LoadPackageInternalInner() [uobjectglobals.cpp:1271]
UE4Editor_CoreUObject!LoadPackageInternal() [uobjectglobals.cpp:1423]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImportInner() [linkerload.cpp:2561]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImport() [linkerload.cpp:2327]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImportInner() [linkerload.cpp:2609]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImport() [linkerload.cpp:2327]
UE4Editor_CoreUObject!FLinkerLoad::Verify() [linkerload.cpp:2105]
UE4Editor_CoreUObject!FLinkerLoad::FinalizeCreation() [linkerload.cpp:2015]
UE4Editor_CoreUObject!FLinkerLoad::Tick() [linkerload.cpp:699]
UE4Editor_CoreUObject!FLinkerLoad::CreateLinker() [linkerload.cpp:404]
UE4Editor_CoreUObject!GetPackageLinker() [linker.cpp:657]
UE4Editor_CoreUObject!LoadPackageInternalInner() [uobjectglobals.cpp:1196]
UE4Editor_CoreUObject!LoadPackageInternal() [uobjectglobals.cpp:1423]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImportInner() [linkerload.cpp:2561]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImport() [linkerload.cpp:2327]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImportInner() [linkerload.cpp:2609]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImport() [linkerload.cpp:2327]
UE4Editor_CoreUObject!FLinkerLoad::Verify() [linkerload.cpp:2105]
UE4Editor_CoreUObject!FLinkerLoad::FinalizeCreation() [linkerload.cpp:2015]
UE4Editor_CoreUObject!FLinkerLoad::Tick() [linkerload.cpp:699]
UE4Editor_CoreUObject!FLinkerLoad::CreateLinker() [linkerload.cpp:404]
UE4Editor_CoreUObject!GetPackageLinker() [linker.cpp:657]
UE4Editor_CoreUObject!LoadPackageInternalInner() [uobjectglobals.cpp:1196]
UE4Editor_CoreUObject!LoadPackageInternal() [uobjectglobals.cpp:1423]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImportInner() [linkerload.cpp:2561]
UE4Editor_CoreUObject!FLinkerLoad::VerifyImport() [linkerload.cpp:2327]

Community References

[Multiple Occurrances] Blueprint can corrupt other ones referencing it (4.14.3)

Crash loading project in 4.14.1

Crash on startup

Fatal error when launch on 4.14.3

Fatal Error on launching

Crash loading project in 4.14.1

Crashing with trace bluprint on weapon

Child actor component crashing the editor.

Engine crashes during blueprint compilation

Edited FirstPersonCharacter BP , crash UE permanently

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Fixed

Component	UE - Gameplay - Blueprint
Affects Versions	4.14, 4.15
Target Fix	4.15

Fix Commit	3222427
Main Commit	3236017

Created	Dec 5, 2016
Resolved	Dec 5, 2016
Updated	Feb 5, 2017

UE-39323

Crash Occurs on Project Load When Casting a Child Actor Component's Parent to the Parent Class

Crash Occurs on Project Load When Casting a Child Actor Component's Parent to the Parent Class

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