Attempt to index nil with "FindFirstChild"

Help and Feedback Scripting Support
#1

This simple script is supposed to check if the object exists, if not, make it.

local recMessages
if not recMessagesApp:FindFirstChild(plr.UserId).Messages.ReceivedMessages then

	recMessages = createConvo(plr, toPlr)

else

	recMessages = recMessagesApp:FindFirstChild(plr.UserId).Messages.ReceivedMessages

end

Error:
ServerScriptService.PhoneHandlerServer:147: attempt to index nil with 'Messages'

Whats’s wrong?

#2

this mean recMessagesApp.plr.Userid = nil

#3

Oh alright. Maybe if should check if the user ID is nil?

#4 
local recMessages
if recMessagesApp:FindFirstChild(plr.UserId) then
if not recMessagesApp:FindFirstChild(plr.UserId).Messages.ReceivedMessages then

	recMessages = createConvo(plr, toPlr)

else

	recMessages = recMessagesApp:FindFirstChild(plr.UserId).Messages.ReceivedMessages
end
end
#5

You need to research Defensive Programming.

The basic concept is remember that variables can be nullable (nil - they have no value).
Such as ‘recMessages’ - by your code that is null by default.
The function FindFirstChild can return a null value.

Hence, attempt to index nil with Messages - you need to write your code defensively
The player’s UserId isn’t null - there’s just no entry in recMessagesApp of plr’s UserId.

--these "local variable = this or that" lines mean, if "this" isn't nil - use this, otherwise use "that"

local playerRecMessages = recMessagesApp:FindFirstChild(plr.UserId)
local messages = playerRecMessages and playerRecMessages:FindFirstChild("Messages")
local received = messages and messages:FindFirstChild("ReceivedMessages")

local recMessages = received or createConvo(plr,toPlr) -- if received is nil, createConvo instead

-Edit- missread part of the script - edited the script to refelct.

@HedTB_Dev - I’m presuming here that “recMessagesApp”, “Messages” and “ReceivedMessages” are all folders or something - not tables?

2 Likes
#6

UserId will never be null if its grabbed from the Player object.

@MdoxxxDSQa

1 Like
#7

we dont know what inside playerRecMessages so yea

player.Userid never be nil but playerRecMessages(player.Userid) maybe nil

#8

No, this is all a GUI. It’s frames. I could show you how the explorer looks if needed.

#9

It looks like ReceivedMessages is the nil, and it couldn’t find it under Messages. You are better off making something like this, maybe?

--these "local variable = this or that" lines mean, if "this" isn't nil - use this, otherwise use "that"

local playerRecMessages = recMessagesApp:FindFirstChild(plr.UserId)
local messages = playerRecMessages and playerRecMessages:FindFirstChild("Messages")
local received = messages and messages:WaitForChild("ReceivedMessages") -- changed to wait?

local recMessages = received or createConvo(plr,toPlr) -- if received is nil, createConvo instead

However, I may be completely wrong and misreading this entire thread.