[Bug] Lua AddEventHandler drops function references from exports

[WLVF]

Summary

In the Lua runtime, AddEventHandler replaces a callable table with its metatable's __call.

Function references received from another resource (e.g. a callback passed through an export) are callable tables, so when the event fires, __call receives the first event argument instead of the reference and InvokeFunctionReference is called with nil.

The same code works when used on Legacy.

Affects client and server (the code is identical in both runtimes, checked in server build 153).

Issue type

Both / Unsure

Repro rate

Always

Server build version

FXServer-early-access b153 win32

OS

WIndows 11 Home 25H2

CPU

AMD Ryzen 9 7900X

GPU

NVIDIA RTX 3080

RAM

64 GB DDR5

Storage type

SSD NVMe

Connection type

Ethernet

ISP and bandwidth

No response

DxDiag

No response

Network graph

No response

Platform

Windows

OS version / distribution

Windows 11 Home 25H2

CPU

AMD Ryzen 9 7900X

RAM

64 GB DDR5

Using txAdmin?

Yes

Hosting provider

Self-hosted

Machine type

None

/perf endpoint output

No response

DDoS protection

No response

ulimit -n value (Linux only)

No response

Docker Compose file (Docker only)

No response

Steps to Reproduce

1. Create two client resources:

-- resource_a/fxmanifest.lua
fx_version 'cerulean'
game 'gta5'
client_script 'client.lua'

-- resource_a/client.lua
exports('Listen', function(name, cb) AddEventHandler(name, cb) end)

-- resource_b/fxmanifest.lua
fx_version 'cerulean'
game 'gta5'
client_script 'client.lua'

-- resource_b/client.lua
CreateThread(function()
    exports.resource_a:Listen('test:event', function(value) print('got', value) end)
    TriggerEvent('test:event', 'hello')
end)

2. ensure resource_a, then ensure resource_b, and join the server.
3. Watch the F8 console.

Expected Behavior

The callback runs and prints "got hello", as it does on Legacy.

Actual Behavior

The handler errors instead of running:

scheduler.lua:430: bad argument #1 to 'InvokeFunctionReference' (string expected, got nil)
> InvokeFunctionReference
> [global chunk] (scheduler.lua:430)
> CreateThreadNow
> handler (scheduler.lua:172)
> [global chunk] (scheduler.lua:135)

Evidence

AddEventHandlerInternal in scheduler.lua:

local eventRoutineMT = getmetatable(eventRoutine)
if eventRoutineMT and eventRoutineMT.__call then
    eventRoutine = eventRoutineMT.__call
end

and later eventRoutine(table_unpack(eventData)) (line 172).

For a function reference, funcref_mt.__call(t, ...) does rawget(t, '__cfx_functionReference'), but t is now the first event argument, so ref is nil at line 430 (InvokeFunctionReference(ref, args)).

Legacy's scheduler.lua only reads __call for debug info and still calls the original handler (handler(table_unpack(data))), which is why it works there.

Additional Context

This issue was hit when using NUI callbacks:
In my use case, a HUD resource registers other resources' UI handlers via AddEventHandler('__cfx_nui:' .. name, callback), and every UI-to-Lua call failed.

Workaround:
Wrap the callback in a local function. Example:

function RegisterHudCallback(name, callback)
    AddEventHandler("__cfx_nui:" .. name, function(...)
        callback(...)
    end)
end

Suggested Fix:
Keep the original table as the handler and call it, or only use __call to derive the handler name.

[wolfram-cfx]

Thanks, we are looking into this.

[WLVF]

Sweet :)

[Gogsi]

Hello,
A fix for this issue has been implemented in the latest version of FiveM for GTAV Enhanced. Please try again and let us know if the issue persists. Thanks for your help!