Is this code bad? It's causing a crash in 4.27!

Development Programming & Scripting C++
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1

When creating a function with parameter type TEnumAsByte it will crash on build. I thought this may have been a migration issue but this happens in an empty project. Anyone else had a crash relating to the Python Plugin? Also I don’t have a D drive…

Assertion failed: !GeneratedWrappedTypes.Contains(TypeRegistryName) [File:D:/Build/++UE4/Sync/Engine/Plugins/Experimental/PythonScriptPlugin/Source/PythonScriptPlugin/Private/PyWrapperTypeRegistry.cpp] [Line: 1780]

Here’s the code:
//header

 UENUM()
 enum Button
 {
   N     UMETA(DisplayName = "N"),
   E     UMETA(DisplayName = "E"),
   S     UMETA(DisplayName = "S"),
   W     UMETA(DisplayName = "W"),
 };
UCLASS()
class EMPTY_API UMyDataAsset : public UDataAsset
{
	GENERATED_BODY()
    public:
	    UFUNCTION(BlueprintPure)
	    uint8 ReturnTwo(TEnumAsByte<Button> SelectedButton);
};

//cpp

uint8 UMyDataAsset::ReturnTwo(TEnumAsByte<Button> SelectedButton)
{
	return 2;
}

(Naturally the real code actually does something useful :wink: )

1 Like
2

TEnumAsByte is the old style for UENUMS.

All Enums should be prefixed with E and Enums should be enum class EButton : uint8

This means that TEnumAsByte, which I don’t think should be used as a parameter anyway is un-necessary, and can be changed to `ReturnTwo(EButton SelectedButton);

Finally, uint8 isn’t a blueprint compatible type as far as I’m aware - you should be using either int32, int, or int64. I could be wrong on that one, however.

3

Hey - thanks for your help that did it! I think uint8 is blueprint compatible (I’m using the function in a blueprint and it works). I believe that’s the C++ equivalent of a Byte.

I had some trouble getting any Data Assets to show up in a blank project but it imported fine now. Do you know why a Data Asset derived from the C++ class wouldn’t show up as a variable type?

Also, what makes that Enum declaration the old style by the way? Is there a docs file on that?

Thanks again!

4

Fair enough. You might want to just return EButton type and include UENUM(BlueprintType) as well then.

As for the data assets, I can’t remember if they have a UCLASS macro in the header file or something similar, but if they do, you’ll need to ensure that it contains Blueprintable.

I can’t remember where I saw it, but it’s quite common practice now that the new style of enum classes is just better in every way than the namespace method.

5

I’ll have an explore. Your help is much appreciated :slight_smile:

1 Like
6

I’ve spent 20 hours trying to understand why my project wasn’t launching.

It was because I didn’t put E before my enum type name.

I re-installed the engine. Verified my files multiple times. Watched dozens of tutorials for recovering UE4 corrupt projects. Went line by line in every single one of my C++ classes multiple times trying to figure out what was breaking my game.

I spent an entire day playing around with python coded plugins that ship with UE4.

It was all because I didn’t put an E before my enum type name.

Thank you for your help, bro.