Unreal Engine Issues and Bug Tracker (UE-44219)

Description

Note: This does not occur when the nativization mode is set to "Inclusive" in the Project settings.

Current workaround: Ensure that the ChildActor class is NOT a data-only Blueprint, by adding script to an event or function graph, for example.

Steps to Reproduce

Launch UE4 editor with a new, blank C++ project.
Create a new Actor-based Blueprint class (MyChildActorBP) and open it in the BP editor.
Click "Class Settings" and check the "Nativize" button.
Save and close the BP editor.
Create another Actor-based Blueprint class (MyActorBP) and open it in the BP editor.
Add a ChildActor component and set the ChildActor class to MyChildActorBP.
Click "Class Settings" and check the "Nativize" button.
Compile and save, then close the BP editor.
Drag an instance of MyActorBP into the current level.
Save the current level (NewMap).
Go to "Edit->Project Settings..." and Project/Maps & Modes, and under "Default Maps" change both to "NewMap."
Switch to Project/Packaging and change "Blueprint Nativization Method" to "Exclusive."
Close the Project Settings window, and go to "File->Package Project->Windows->Windows (64-bit)"
Choose/create a folder for packaging and accept.
Compile errors should occur during packaging:

UATHelper: Packaging (Windows (64-bit)): xgConsole: MyActorBP__pf1010915279.cpp
UATHelper: Packaging (Windows (64-bit)): xgConsole: D:\dev\Epic\UE4\Dev-Framework\UE_44123_2\Intermediate\Plugins\WindowsNoEditor\NativizedAssets\Source\NativizedAssets\Private\MyActorBP__pf1010915279.cpp(230): error C2653: 'AMyChildActorBP_C__pf1010915279': is not a class or namespace name
UATHelper: Packaging (Windows (64-bit)): xgConsole: D:\dev\Epic\UE4\Dev-Framework\UE_44123_2\Intermediate\Plugins\WindowsNoEditor\NativizedAssets\Source\NativizedAssets\Private\MyActorBP__pf1010915279.cpp(256): error C2653: 'AMyChildActorBP_C__pf1010915279': is not a class or namespace name
UATHelper: Packaging (Windows (64-bit)): xgConsole: D:\dev\Epic\UE4\Dev-Framework\UE_44123_2\Intermediate\Plugins\WindowsNoEditor\NativizedAssets\Source\NativizedAssets\Private\MyActorBP__pf1010915279.cpp(257): error C2653: 'AMyChildActorBP_C__pf1010915279': is not a class or namespace name
UATHelper: Packaging (Windows (64-bit)): xgConsole: D:\dev\Epic\UE4\Dev-Framework\UE_44123_2\Intermediate\Plugins\WindowsNoEditor\NativizedAssets\Source\NativizedAssets\Private\MyActorBP__pf1010915279.cpp(258): error C2065: 'AMyChildActorBP_C__pf1010915279': undeclared identifier
UATHelper: Packaging (Windows (64-bit)): xgConsole: D:\dev\Epic\UE4\Dev-Framework\UE_44123_2\Intermediate\Plugins\WindowsNoEditor\NativizedAssets\Source\NativizedAssets\Private\MyActorBP__pf1010915279.cpp(258): error C2653: 'AMyChildActorBP_C__pf1010915279': is not a class or namespace name
UATHelper: Packaging (Windows (64-bit)): xgConsole: D:\dev\Epic\UE4\Dev-Framework\UE_44123_2\Intermediate\Plugins\WindowsNoEditor\NativizedAssets\Source\NativizedAssets\Private\MyActorBP__pf1010915279.cpp(258): error C2672: 'NewObject': no matching overloaded function found
UATHelper: Packaging (Windows (64-bit)): xgConsole: D:\dev\Epic\UE4\Dev-Framework\UE_44123_2\Intermediate\Plugins\WindowsNoEditor\NativizedAssets\Source\NativizedAssets\Private\MyActorBP__pf1010915279.cpp(258): error C2974: 'NewObject': invalid template argument for 'T', type expected
UATHelper: Packaging (Windows (64-bit)): xgConsole: d:\dev\epic\ue4\dev-framework\engine\source\runtime\coreuobject\public\UObject/UObjectGlobals.h(1245): note: see declaration of 'NewObject'
UATHelper: Packaging (Windows (64-bit)): xgConsole: D:\dev\Epic\UE4\Dev-Framework\UE_44123_2\Intermediate\Plugins\WindowsNoEditor\NativizedAssets\Source\NativizedAssets\Private\MyActorBP__pf1010915279.cpp(259): error C3536: '__Local__2': cannot be used before it is initialized
UATHelper: Packaging (Windows (64-bit)): xgConsole: D:\dev\Epic\UE4\Dev-Framework\UE_44123_2\Intermediate\Plugins\WindowsNoEditor\NativizedAssets\Source\NativizedAssets\Private\MyActorBP__pf1010915279.cpp(259): error C2664: 'int32 TArray<UObject *,FDefaultAllocator>::Add(UObject *const &)': cannot convert argument 1 from 'int' to 'UObject *&&'
UATHelper: Packaging (Windows (64-bit)): xgConsole: D:\dev\Epic\UE4\Dev-Framework\UE_44123_2\Intermediate\Plugins\WindowsNoEditor\NativizedAssets\Source\NativizedAssets\Private\MyActorBP__pf1010915279.cpp(259): note: Reason: cannot convert from 'int' to 'UObject *'
UATHelper: Packaging (Windows (64-bit)): xgConsole: D:\dev\Epic\UE4\Dev-Framework\UE_44123_2\Intermediate\Plugins\WindowsNoEditor\NativizedAssets\Source\NativizedAssets\Private\MyActorBP__pf1010915279.cpp(259): note: Conversion from integral type to pointer type requires reinterpret_cast, C-style cast or function-style cast
UATHelper: Packaging (Windows (64-bit)): xgConsole: 
UATHelper: Packaging (Windows (64-bit)): xgConsole: Error executing D:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\bin\amd64\cl.exe (tool returned code: 2)

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Fixed

Component	UE - Gameplay - Blueprint
Target Fix	4.17

Fix Commit	3416425
Main Commit	3431398

Created	Apr 20, 2017
Resolved	May 1, 2017
Updated	Sep 23, 2019

UE-44219

BP - Exclusive nativization will fail at cook time if a BP class includes a ChildActorComponent with a Data-Only BP set as the ChildActor class.

BP - Exclusive nativization will fail at cook time if a BP class includes a ChildActorComponent with a Data-Only BP set as the ChildActor class.

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