Crash of UE4 when trying to call GetAllActorsOfClass

[danielkcz]

I am not sure if I am not simply doing something wrong. I am fiddling with UE4 for last 2 months only, so I might be missing something obvious here. Either way I have official release of UE 4.14.3 with Unreal.JS plugin from marketplace. I am on Windows 10 x64.

I start UE4, open javascript console and just type in World.GetAllActorsOfClass(Actor) and execute it which makes UE4 crash immediately. Not sure if there are some logs available that could help. I also tried somewhat simpler command like World.GetGameInstance(), but with a same result.

Any advice please ?

[nakosung]

World? Not a GWorld? I think you tried to call non static function as a static function. It definitely seems like a bug. :)

Please try with GWorld (for play in editor) or Root.GetEngine().GetEditorWorld() (for editor) instead.

[danielkcz]

Hmm, strange. I was seeing the GWorld variable in some examples, but when I try to type it in the Javascript console, it's not offered at all and it doesn't really exists. I did not really found any meaning of that variable anywhere :( How can I get that variable please?

Either way in my opinion executing something invalid in javascript console shouldn't cause a crash of UE. Do you consider that a good behavior ? :)

In fact it did crash when I called a same thing through Javascript Component and script file which is even more strange since I had the try...catch block as many examples have.

[nakosung]

@FredyC In editor environment there is no GWorld. You can access GWorld in PIE context. As I mentioned earlier, it should not crash under any circumstances so I open a new issue "Crash while calling non static function as static function."

[danielkcz]

So GWorld is a global variable assigned when script is running in PIE or standalone? Is there some list of variables like that? Might be useful :)

Thanks for opening an issue :)

[nakosung]

You can grab list by _ = require('lodash'); _.filter(_.keys(this),x => this[x] instanceof UObject), which gives you Context, Root under editor env and Context, Root, GWorld under PIE.

I investigated the problem you reported but it actually turned out the crash was caused within internal unreal engine code, so I think that this issue should be reported to unreal engine. :)

[LanslotChung]

let asset = StaticMesh.Load('/Game/StarterContent/Shapes/Shape_Cube.Shape_Cube')

class MyBox extends StaticMeshActor {
ctor() {
this.StaticMeshComponent.SetStaticMesh(asset)
this.StaticMeshComponent.SetMobility('Movable')
}
ReceiveActorBeginCursorOver() {
super.ReceiveActorBeginCursorOver() // not necessary
let pos = this.GetActorLocation()
pos.Z += 10
this.SetActorLocation(pos)
}
}

function test() {
console.log("TEST");
let MyBox_C = require('uclass')()(global,MyBox)
let box = new MyBox_C(GWorld)
let PC = Root.GetEngine.GetEditorWorld.GetAllActorsOfClass(PlayerController).OutActors[0]
PC.bEnableMouseOverEvents = true
PC.bShowMouseCursor = true
return function () {
box.DestroyActor()
}
}

test();

Error: file:///e:/Unreal/Project/MyProject/Content/Scripts/test.js:20: TypeError: Cannot read property 'GetEditorWorld' of undefined
Error: TypeError: Cannot read property 'GetEditorWorld' of undefined
Error: at test (file:///e:/Unreal/Project/MyProject/Content/Scripts/test.js:20:26)
Error: at file:///e:/Unreal/Project/MyProject/Content/Scripts/test.js:28:1
Error: at file:///e:/Unreal/Project/MyProject/Content/Scripts/test.js:29:3