Did 4.15 change the rules about plugin blueprint libraries?

Development Programming & Scripting Blueprint
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1

We recently upgraded our 4.13 project to 4.15. Now I can’t build a shipping version of our plugin any more, although Development-Editor works fine.
When I build shipping I get:

2>D:\Projects\VRProjects\Engine\Plugins\Holospark\VRTools\Source\VRToolsFunctionLibrary.h(7): error C2504: ‘UBlueprintFunctionLibrary’: base class undefined

The file in question starts with:

#pragma once

#include “VRToolsFunctionLibrary.generated.h”

UCLASS()
class UVRToolsFunctionLibrary : public UBlueprintFunctionLibrary
{
GENERATED_BODY()

public:

This all works fine in Development-Editor, and worked in Shipping in 4.13. I thought that perhaps the new include what you need code might be at fault, so I tried adding “Kismet” to the list of dependencies, and that gave me:

2>EXEC : error : Non-editor build cannot depend on non-redistributable modules. D:\Projects\VRProjects\Engine\Binaries\Win64\UE4Game-Win64-Shipping.exe depends on …very long list… ‘BlueprintProfiler’, ‘Kismet’.

So apparently you can’t do that. But I find it hard to believe that you aren’t supposed to be able to make a blueprint library in a plugin any more. I note that our copy of FModStudioOculus has exactly the same issue with their blueprint library.

What’s the new magic to make this work?

Thanks

Rick

2

Try adding this to your includes at the top of that file:

#include "Kismet/BlueprintFunctionLibrary.h"

That should resolve that issue (although you could be missing other includes depending on what classes and such you reference).

3

Yeah, I tried that. That causes:

D:\Projects\VRProjects\Engine\Plugins\Holospark\VRTools\Source\VRToolsFunctionLibrary.h(9): error C2664: ‘UObject *UVRToolsFunctionLibrary::GetDefaultObject(TSubclassOf)’: cannot convert argument 1 from ‘UClass *’ to ‘TSubclassOf’
2> D:\Projects\VRProjects\Engine\Plugins\Holospark\VRTools\Source\VRToolsFunctionLibrary.h(9): note: use of undefined type ‘TSubclassOf’
2> D:\Projects\VRProjects\Engine\Plugins\Holospark\VRTools\Source\VRToolsFunctionLibrary.h(61): note: see declaration of ‘TSubclassOf’

in:
UCLASS()
class UVRToolsFunctionLibrary : public UBlueprintFunctionLibrary
{
GENERATED_BODY()

And this works in development-editor, and it used to work in 4.13. So I figured there’s something else I need to do.

4

Aha! OK, you were correct, liberal sprinkling of #include statements gets me past most of the problems. The one I posted above was actually caused by a function in the blueprint library, but confusingly showed up on the Generated_Body line.