Having an error "attempt to call a RBXScriptConnection value"

vojin154 · June 1, 2024, 7:17pm

Hello! I made myself a module script to handle hooks, so everything runs in 1 function for each hook. After some time, I started running into problems regarding the module script randomly stopping to work without an error. After hours of debugging using pcalls and prints, I found out, I’m getting “attempt to call a RBXScriptConnection value”, from what it seems, I seem to get it mostly, when using the “Players” service, but it’s not only that.

The error happens in this function:

function Hooks:ConnectHooks(object, func)
	local success, errorMessage = pcall(game:GetService(object)[func]:Connect(function(...)
		for _, v in pairs(self._function_hooks[object][func]) do
			v(...) --Errors here, when running callbacks
		end
	end))
	
	if not success then
		warn(debug.traceback(errorMessage, 4))
	end
end

Error:

Example of one of the hooks, which errors me.

If anything else is needed, I can provide more.

7z99 · June 1, 2024, 11:25pm

It is because you are passing the RBXScriptConnection itself as the first param of the pcall which expects a function.

The following:

pcall(game:GetService(object)[func]:Connect(function(...)
	for _, v in pairs(self._function_hooks[object][func]) do
		v(...) --Errors here, when running callbacks
	end
end))

is equivalent to the following (but without the pcall):

game:GetService(object)[func]:Connect(function(...)
	for _, v in pairs(self._function_hooks[object][func]) do
		v(...) --Errors here, when running callbacks
	end
end)() -- note the extra parentheses

There is no need for a pcall here.

vojin154 · June 2, 2024, 7:24am

Well the pcall was to find what’s causing this problem, so I assume the problem is completely different…

7z99 · June 2, 2024, 7:27am

The pcall wouldn’t have caught the error, the issue is either the pcall itself or because something in self._function_hooks[object][func] is not a function (is a connection)

vojin154 · June 2, 2024, 7:30am

Hm weird, all should be fine. The isValid function specifically checks for all this stuff, so it should be fine?

function Hooks:AddHook(object, func, id, callback)
	id = tostring(id)

	if not self:IsValidHook(object, func, id, callback) then
		pcall(error("[HOOKS] FAILED TO HOOK " .. object .. " WITH " .. func))
		return
	end

	self:CheckHooks(object, func)

	if object == "RunService" and id ~= "RunServiceHooks" then
		--pcall(error("[HOOKS] TRIED TO HOOK RUNSERVICE IN THE WRONG PLACE. PLEASE USE HookRunService() INSTEAD"))
		pcall(error(debug.traceback("[HOOKS] TRIED TO HOOK RUNSERVICE IN THE WRONG PLACE. PLEASE USE HookRunService() INSTEAD")))
		return
	end

	if self._function_hooks[object][func][id] then
		pcall(error("[HOOKS] HOOK ID ALREADY EXISTS: " .. id))
		return
	end

	self._function_hooks[object][func][id] = callback

	return id
end

local function isValid(object, method, id, callback)
	local function isntEmpty(str)
		return str ~= ""
	end

	if object and method and id and callback and (type(callback) == "function") then --Split the if statements for better readability
		if isntEmpty(object) and isntEmpty(method) and isntEmpty(id) then
			return true
		end
	end
end

function Hooks:IsValidHook(object, func, id, callback)
	return (isValid(object, func, id, callback) and game:GetService(object) and game:GetService(object)[func]) or false
end

7z99 · June 2, 2024, 7:35am

Where is line 147 of your script? That’s where the error is being outputted from as per your original post, I just want to make sure I’m looking in the right place

vojin154 · June 2, 2024, 7:37am

At the time, line 147 was the Hooks:ConnectHook func, when calling the callbacks

function Hooks:ConnectHooks(object, func)
	game:GetService(object)[func]:Connect(function(...)
		for _, v in pairs(self._function_hooks[object][func]) do
			v(...) --This was line 147 at the time
		end
	end)
end

Saying at the time, because I changed stuff like removing the pcalls.

7z99 · June 2, 2024, 7:43am

Ok, that’s very odd because that shouldn’t have caused a warning but an error. Could you try printing typeof(v) and see if it sometimes gives you a function and other times gives you rbxscriptconnection?

Could you show me how you’re populating self._function_hooks[object][func]

vojin154 · June 2, 2024, 7:49am

So first, typeof(v) gives me all functions

And second, at this point I feel, like sending the whole script would be better.

7z99 · June 2, 2024, 7:50am

If you could do that and send how you’re using it that might be the most efficient way to try figuring out what’s going on here

Edit: ok I got it, in your connect hooks function, I am not getting the warning with this:

function Hooks:ConnectHooks(object, func)
	game:GetService(object)[func]:Connect(function(...)
		for _, v in pairs(self._function_hooks[object][func]) do
			v(...)
		end
	end)
end

is there something special you do to make the warn happen?

vojin154 · June 2, 2024, 7:54am

Accidentally edited my last message.

Here’s the module

--vojin154 copyright :D

local Hooks = {}

---------------------------------SERVICE HOOKS----------------------------------
Hooks._function_hooks = {}
Hooks._run_service_hooks = {}

function Hooks:AddHook(object, func, id, callback)
	id = tostring(id)

	if not self:IsValidHook(object, func, id, callback) then
		pcall(error("[HOOKS] FAILED TO HOOK " .. object .. " WITH " .. func))
		return
	end

	self:CheckHooks(object, func)

	if object == "RunService" and id ~= "RunServiceHooks" then
		--pcall(error("[HOOKS] TRIED TO HOOK RUNSERVICE IN THE WRONG PLACE. PLEASE USE HookRunService() INSTEAD"))
		pcall(error(debug.traceback("[HOOKS] TRIED TO HOOK RUNSERVICE IN THE WRONG PLACE. PLEASE USE HookRunService() INSTEAD")))
		return
	end

	if self._function_hooks[object][func][id] then
		pcall(error("[HOOKS] HOOK ID ALREADY EXISTS: " .. id))
		return
	end

	self._function_hooks[object][func][id] = callback

	return id
end

function Hooks:HookRunService(id, waitTime, callback)
	waitTime = waitTime or 0
	self._run_service_hooks[id] = {
		callback = callback,
		waitTime = waitTime,
		t = waitTime
	}

	return id
end

function Hooks:RemoveRunServiceHook(id)
	if self._run_service_hooks[id] then
		self._run_service_hooks[id] = nil
	end
end

function Hooks:RemoveHook(id)
	self:RemoveTableEntry(id, self._function_hooks)
end

---------------------------------EVENT HOOKS------------------------------------
Hooks._event_hooks = {}

function Hooks:HookEvent(object, event, id, callback)
	if (not object) or (not event) or (not object[event]) or (not id) or (id == "") or not callback or (type(callback) ~= "function") then
		pcall(error("[HOOKS] FAILED TO HOOK " .. object .. " WITH " .. event))
		return
	end

	self:CheckEvents(object, event)

	if self._event_hooks[object][event][id] then
		pcall(error("[HOOKS] HOOK ID ALREADY EXISTS: " .. id))
		return
	end

	self._event_hooks[object][event][id] = callback

	return id
end

function Hooks:RemoveEvent(id)
	self:RemoveTableEntry(id, self._event_hooks)
end

---------------------------------UTIL FUNCTIONS---------------------------------
function Hooks:GetHook(id)
	for _, object in pairs(self._function_hooks) do
		for _, func in pairs(object) do
			for i, v in pairs(func) do
				if i == id then
					return i, v
				end
			end
		end
	end
end

function Hooks:GetEvent(id)
	for _, object in pairs(self._event_hooks) do
		for _, event in pairs(object) do
			for i, v in pairs(event) do
				if i == id then
					return i, v
				end
			end
		end
	end
end

---------------------------------CORE FUNCTIONS---------------------------------
local function isValid(object, method, id, callback)
	local function isntEmpty(str)
		return str ~= ""
	end

	if object and method and id and callback and (type(callback) == "function") then --Split the if statements for better readability
		if isntEmpty(object) and isntEmpty(method) and isntEmpty(id) then
			return true
		end
	end
end

function Hooks:IsValidHook(object, func, id, callback)
	return (isValid(object, func, id, callback) and game:GetService(object) and game:GetService(object)[func]) or false
end

function Hooks:IsValidEvent(object, event, id, callback)
	return (isValid(object, event, id, callback) and object[event]) or false
end

function Hooks:RemoveTableEntry(id, hookType)
	for _, object in pairs(hookType) do
		for _, method in pairs(object) do
			for i, _ in pairs(method) do
				if i == id then
					method[i] = nil
				end
			end
		end
	end
end

function Hooks:ConnectHooks(object, func)
	game:GetService(object)[func]:Connect(function(...)
		for _, v in pairs(self._function_hooks[object][func]) do
			warn(typeof(v))
		end
	end)
end

function Hooks:ConnectEvents(object, event)
	object[event]:Connect(function(...)
		for _, v in pairs(self._event_hooks[object][event]) do
			v(object, ...)
		end
	end)
end

function Hooks:CheckHooks(object, func)
	if self._function_hooks[object] == nil then
		self._function_hooks[object] = {}
	end

	if self._function_hooks[object][func] then
		return
	end

	self._function_hooks[object][func] = {}

	self:ConnectHooks(object, func)
end

function Hooks:CheckEvents(object, event)
	if self._event_hooks[object] == nil then
		self._event_hooks[object] = {}
	end

	if self._event_hooks[object][event] then
		return
	end

	self._event_hooks[object][event] = {}

	Hooks:ConnectEvents(object, event)
end

function Hooks:ExecuteRunServiceHooks(dt)
	for _, v in pairs(self._run_service_hooks) do
		if v.t > 0 then
			v.t -= dt
		else
			v.callback(dt)
			v.t = v.waitTime
		end
	end
end

Hooks:AddHook("RunService", "Heartbeat", "RunServiceHooks", function(dt)
	Hooks:ExecuteRunServiceHooks(dt)
end)

return Hooks

And it’s used by using either AddHook or HookEvent, AddHook is used to hook services, while HookEvent is to hook stuff like Button.MouseButton1Click.

Here’s an example of AddHook:

HooksModule:AddHook("Players", "PlayerRemoving", script.Name .. "PlayerRemoving", function(player)
	local playerVoted = Votes._players_voted[player]
	if playerVoted then
		Votes._maps_voted[playerVoted] -= 1
	end
end)

And here’s HookEvent:

local HooksModule = require(game:GetService("ReplicatedStorage").Modules.Hooks)

local currentlyOpened
for _, v in pairs(script.Parent:GetChildren()) do
	if v:IsA("Folder") then
		HooksModule:HookEvent(v.Button, "MouseButton1Click", script.Name, function(o)
			if currentlyOpened and currentlyOpened ~= v.Frame then
				currentlyOpened.Visible = false
			end

			v.Frame.Visible = not v.Frame.Visible
			currentlyOpened = v.Frame --Doesn't matter, if it's closed or not. It will be force closed either way.
		end)
	end
end

Additionally there’s to hook RunService, but I didn’t include it as it pretty much goes to AddHook.

vojin154 · June 2, 2024, 7:57am

Not sure if this will tell anything, but sometimes I get this:

Which seems to point to ConnectHooks.

7z99 · June 2, 2024, 7:59am

Ok got it, what are you doing that causes you to get the warning though? I can’t get the warning to occur. Or do you have multiple hooks and it could be more than 1 it’s stemming from?

vojin154 · June 2, 2024, 8:10am

Multiple. I have no idea where the problem comes from.

7z99 · June 2, 2024, 8:12am

Ok, in that case, inside your AddHook function, add another check that checks the type that callback is, and ensures it’s a function, eg:

	if type(callback) ~= 'function' then
		error('Callback was not a function')
	end

	self._function_hooks[object][func][id] = callback

see if that helps determine where this is coming from

vojin154 · June 2, 2024, 8:31am

Still nothing. I’m starting to get confused, this feels so stupid.

7z99 · June 2, 2024, 9:13pm

Yeah I’m at a loss here, sorry

vojin154 · June 4, 2024, 2:14pm

Well, I’m assuming it was throwing RBXScriptConnection error, because I was using pcalls or at least something like that, so most likely the issue is different. However due to Roblox not telling me what, I feel meh about this.

SeargentAUS · June 5, 2024, 9:10am

Are you able to temporarily remove the pcalls until a clear error is seen, to ensure that what you are trying to remedy is actually the error.

vojin154 · June 7, 2024, 8:25pm

I have removed the pcalls long ago.