Reference ID
10d11f1a-4b2a-f5c2-0d30-c09bb1533952
Please select what you are reporting on:
Verse
What Type of Bug are you experiencing?
Verse
Summary
When using a cancelable object in Verse and attempting to use it later in a spawn coroutine, an unhandled exception occurs, leading to crash in fortnite, but uefn report nothing.
Fatal error!
Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x000000000000002c
0x00007ff7142c9953 FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff7142c908c FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff716eb1af4 FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff7142c9a4b FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff7142c908c FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff7154bd687 FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff7154bd5f8 FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff7141ea243 FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff7141ea875 FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff7140ef51a FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff7140ee44a FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff7140eef71 FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff714dc78ef FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff714dc7752 FortniteClient-Win64-Shipping.exe!UnknownFunction []
0x00007ff8810d257d KERNEL32.DLL!UnknownFunction []
Steps to Reproduce
- Start on a fresh island.
- Use the
reproduce_deviceand populate a player spawner. - Launch the session.
using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }
using { /Fortnite.com/Characters }
using { /Fortnite.com/Game }
reproduce_device := class(creative_device):
@editable
PlayerSpawner: player_spawner_device = player_spawner_device{}
OnBegin<override>()<suspends>:void=
PlayerSpawner.SpawnedEvent.Subscribe(OnPlayerSpawed)
OnPlayerSpawed(Agent: agent):void=
if(Char:=Agent.GetFortCharacter[]):
C := Char.EliminatedEvent().Subscribe(OnPlayerEliminated)
#Not Safe
spawn:
AwaitPlayerEliminated(Char, C)
#Not Safe
AwaitPlayerEliminated(Character: fort_character, Cancelable : cancelable)<suspends>:void=
Character.EliminatedEvent().Await()
Sleep(1.0)
Cancelable.Cancel()
#Not Safe
OnPlayerEliminated(ER: elimination_result):void=
Print("Eliminated", ?Duration:=6.0)
Expected Result
No crash or report error in uefn
Observed Result
It appears that the cancelable object gets garbage collected before use, resulting in a use-after-free exception. This issue occurs specifically when launching a fresh session from UEFN or pushing to an edit session. However, it does not happen when pushing only verse code.
Platform(s)
windows