Player is nil in Module Script?
Boom boom complicated metatables ahead!
Great, I'm inexperienced in writing questions for I have only written answers, ain't that dandy?
My issue is that whenever I try to access the player in a module script, it thinks it's nil, here is the source code
local DS = game:GetService("DataStoreService"):GetDataStore("Stuff_DS_V1");
local PM = {} do
PM.RegisteredPlayers = {};
local Methods = {};
Methods.GetData = function(plr, key, defaultVal)
local data = DS:GetAsync(plr.player.userId.."_"..key);
if data then
if type(defaultVal) == "table"then
return data;
else
return data;
end
else
return defaultVal;
end
end
Methods.SaveData = function(plr, key, val)
DS:SetAsync(plr.Player.userId.."_"..key, val);
end
Methods.LoadData = function(plr)
local data = plr:GetData("Stats", {Blox = 0, Lvl = 1, Exp = 0});
plr.Blox = data.Blox;
plr.Lvl = data.Lvl;
plr.Exp = data.Exp;
local backpack = plr:GetData("Backpack", {Backpack = {"Sword", "Classic"}, Equipped = {Melee = "Sword",Grave = "Classic"}});
for i,v in pairs(backpack.Backpack) do
table.insert(plr.Backpack, v);
end
for i,v in pairs(backpack.Equipped) do
plr.Equipped[tostring(i)] = tostring(v);
end
end
Methods.Destroy = function(plr)
PM.RegisteredPlayers[tostring(plr.player.userId)] = nil;
end
PM.RegisterPlayer = function(plr)
if PM.RegisteredPlayers[tostring(plr.userId)] == nil then
local Data = {};
Data.Blox = 0;
Data.Lvl = 0;
Data.Exp = 0;
Data.Backpack = {};
Data.Equipped = {};
setmetatable(Data, {
__index = function(tab, key)
if key:lower() == "player" then
return plr;
elseif Methods[key] then
return function(...)
return Methods[key](...);
end
elseif Data[key] then
return Data[key];
else
print("ERROR: "..key.." is nil.")
end
end,
});
PM.RegisteredPlayers[tostring(plr.userId)] = Data;
return Data;
else
print(plr.Name.." is already registered and will be allowed to access the custom methods.");
return PM.RegisteredPlayers[tostring(plr.userId)];
end
end
PM.Get = function(plr)
if plr == nil then print("Argument 'plr' is nil.") return; end
print("Getting the Player Table for: "..plr.Name);
return PM.RegisterPlayer(plr);
end
end
return PM;
That is the module script, as you can see, if the index is "player", then it returns the player object
And this is the normal handler script
local PM = require(game.ServerScriptService:WaitForChild("Modules"):WaitForChild("PlayerManager"));
game.Players.PlayerAdded:connect(function(plr)
local makeshiftPlayer = PM.Get(plr);
print(makeshiftPlayer.Player.userId);
makeshiftPlayer:LoadData();
end)
game.Players.PlayerRemoving:connect(function(plr)
local makeshiftPlayer = PM:Get(plr);
makeshiftPlayer:SaveData("Stats", {Blox = makeshiftPlayer.Blox, Lvl = makeshiftPlayer.Lvl, Exp = makeshiftPlayer.Exp});
makeshiftPlayer:SaveData("Backpack",{Backpack = plr.Backpack, Equipped = plr.Equipped});
wait();
makeshiftPlayer:Destroy();
end)
But what's interesting is, the error only happens when a player leaves, I've already tested if the player is nil if you send it to a module, it is not.
The very error happens in the PM.Get function, which isn't even all that complicated, but even the script can't find the player for some reason.
11:49:06.526 - ServerScriptService.Modules.PlayerManager:74: attempt to concatenate field 'Name' (a nil value) 11:49:06.527 - Stack Begin 11:49:06.529 - Script 'ServerScriptService.Modules.PlayerManager', Line 74 - method Get 11:49:06.530 - Script 'ServerScriptService.Scripts.Player', Line 10 11:49:06.531 - Stack End
If I remove the 'print("Getting the Player Table for: "..plr.Name)', it errors in the Methods.SaveData function, where it says userId is nil.
11:49:06.526 - ServerScriptService.Modules.PlayerManager:68: attempt to concatenate field 'userId' (a nil value) 11:49:06.527 - Stack Begin 11:49:06.529 - Script 'ServerScriptService.Modules.PlayerManager', Line 68 - method SaveData 11:49:06.530 - Script 'ServerScriptService.Scripts.Player', Line 11 11:49:06.531 - Stack End
And, like the other error, it only errors when you leave. I suspected that when you index 'player' it returns nil since the player left.
How can I access the player, without it being nil?
0
1 answer
ROBLOX Objects shouldn't be able to have fields like Name or userId set to nil, so this is a weird error. My instinct was that plr in PM.Get wasn't actually a Player object.
Adding this line of debugging:
if plr == nil then print("Argument 'plr' is nil.") return; end
print("This is the player: ", plr)
print("Getting the Player Table for: "..plr.Name);
This is indeed the case:
This is the player: table: 0E0360B0
This is really weird, since I checked that plr was indeed being passed in as a Player object:
print("PlayerRemoving(", plr, ")")
local makeshiftPlayer = PM:Get(plr);
-- PlayerRemoving( Player1 )
Where is the table coming from?
Hint: one character is wrong PM:Get(plr).
You're calling PM.Get as a method, but it wasn't designed to be used as one! Thus the plr argument is actually being populated as PM!
A tweak that would have helped catch this is adding a metamethod to the PM module table to error if you try to grab a field (like Name or userId) that doesn't exist:
setmetatable(PM, {__index = function(_, key) error("`" .. key .. "` is not a function provided by this module", 2) end})
You can also add checks that the first parameter is never PM.
Cleanup Aside
GetData can be simplified a lot:
function Methods.GetData(plr, key, defaultValue)
return DS:GetAsync(plr.player.userId .. ("_" .. key)) or defaultValue
end