What is assertion failed?

[urgentnotice]

I’m currently working on an inventory system using profile service and I am not too sure as to what I am doing. I wrote some code and everything works as intended except I keep getting this “assertion failed!” error message from my the second assertion of my :Set function

function PlayerDataHandler:Set(plr, key, value)
	local profile = getProfile(plr)
	assert(profile.Data[key], string.format("Data does not exist for key: %s", key))

	assert(type(profile.Data[key]) == type(value)) --assertion failed?

	profile.Data[key] = value
end

It was working perfectly fine yesterday before I tried making an equip and unequip function today.

function PlayerDataHandler:Equip(plr, itemName)
	self:Update(plr, "Inventory", function(current)
		if table.find(current, itemName) then
			table.remove(current, table.find(current, itemName))
			self:Update(plr, "Equipped", function(current)
				table.insert(current, itemName)
			end)
		else
			print(plr, "does not have", itemName )
		end
		table.insert(current, itemName)

		return current
	end)

	local item = game.ReplicatedStorage.Assets:FindFirstChild(itemName)
	if not item then return end
	
end

function PlayerDataHandler:Unequip(plr, itemName)
	self:Update(plr, "Equipped", function(current)
		if table.find(current, itemName) then
			table.remove(current, table.find(current, itemName))
			self:Update(plr, "Inventory", function(current)
				table.insert(current, itemName)
			end)
		else
			print(plr, "does not have", itemName )
		end
		table.insert(current, itemName)

		return current
	end)

	local item = game.ReplicatedStorage.Assets:FindFirstChild(itemName)
	if not item then return end
end

I honestly don’t completely understand what I’m doing with self:Update but the yt video I was following used it so I though it would be better for me to use it. I can barely find any info on assertion failed.

Any help would be greatly appreciated

[RobloxHasTalentR (LOLLLLLLLLL_1)]

Equip and Unequip functions without the redundant table.insert calls:

function PlayerDataHandler:Equip(plr, itemName)
	self:Update(plr, "Inventory", function(current)
		if table.find(current, itemName) then
			table.remove(current, table.find(current, itemName))
			self:Update(plr, "Equipped", function(equipped)
				table.insert(equipped, itemName)
			end)
		else
			print(plr, "does not have", itemName)
		end
		return current
	end)

	local item = game.ReplicatedStorage.Assets:FindFirstChild(itemName)
	if not item then return end
end

function PlayerDataHandler:Unequip(plr, itemName)
	self:Update(plr, "Equipped", function(current)
		if table.find(current, itemName) then
			table.remove(current, table.find(current, itemName))
			self:Update(plr, "Inventory", function(inventory)
				table.insert(inventory, itemName)
			end)
		else
			print(plr, "does not have", itemName)
		end
		return current
	end)

	local item = game.ReplicatedStorage.Assets:FindFirstChild(itemName)
	if not item then return end
end

Ensuring Data Initialization

Make sure that profile.Data["Inventory"] and profile.Data["Equipped"] are initialized properly:

function PlayerDataHandler:InitializeProfile(plr)
	local profile = getProfile(plr)
	profile.Data.Inventory = profile.Data.Inventory or {}
	profile.Data.Equipped = profile.Data.Equipped or {}
end

[urgentnotice]

Hi sorry for the late reply I’m not sure where exactly I should call Initialize profile but I did it right after I called equipped or add to inventory. Its not that the functions dont work, they work perfectly and also save as intended but I am getting this “assertion failed!” error that really doesnt do anything

[urgentnotice]

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[7z99 (cody)]

Can you show where you’re calling :Set? I don’t see it in any of the snippets

In either case the assertion is failing because your types are mismatched, your profile.Data[key] could be, say, a string, whereas value could be something else like nil or boolean or etc

[urgentnotice]

Hi sorry for the late response set is called whenever Update is called

function PlayerDataHandler:Update(plr, key, callback)
	local profile = getProfile(plr)

	local oldData = self:Get(plr, key)
	local newData = callback(oldData)

	self:Set(plr, key, newData)
end

and I used self:Update for both my equip and unequip functions

[RobloxHasTalentR (LOLLLLLLLLL_1)]

Sorry for late response but let’s try this without assert

Modified Code without Assertions:

PlayerDataHandler:Set

function PlayerDataHandler:Set(plr, key, value)
	local profile = getProfile(plr)
	
	-- Temporarily comment out the assertions for debugging
	-- assert(profile.Data[key], string.format("Data does not exist for key: %s", key))
	-- assert(type(profile.Data[key]) == type(value), string.format("Type mismatch for key: %s. Expected %s but got %s", key, type(profile.Data[key]), type(value)))
	
	profile.Data[key] = value
end

PlayerDataHandler:Update

function PlayerDataHandler:Update(plr, key, callback)
	local profile = getProfile(plr)
	
	local oldData = self:Get(plr, key)
	print("Updating key: ", key, "Old Data Type: ", type(oldData))
	
	local newData = callback(oldData)
	print("New Data Type: ", type(newData))
	
	self:Set(plr, key, newData)
end

Ensure Proper Profile Initialization:

local function createProfileData()
	return {
		Inventory = {},
		Equipped = {}
	}
end

function getProfile(plr)
	local profile = profiles[plr]
	if not profile then
		profile = { Data = createProfileData() }
		profiles[plr] = profile
	end
	return profile
end

Call Profile Initialization:

Ensure that the profile is initialized before calling equip or unequip functions:

function PlayerDataHandler:Equip(plr, itemName)
	local profile = getProfile(plr) -- Ensure profile is initialized here
	self:Update(plr, "Inventory", function(current)
		print("Equip - Inventory Before: ", current)
		if table.find(current, itemName) then
			table.remove(current, table.find(current, itemName))
			self:Update(plr, "Equipped", function(equipped)
				table.insert(equipped, itemName)
				print("Equip - Equipped After: ", equipped)
				return equipped
			end)
		else
			print(plr, "does not have", itemName)
		end
		print("Equip - Inventory After: ", current)
		return current
	end)
	local item = game.ReplicatedStorage.Assets:FindFirstChild(itemName)
	if not item then return end
end

function PlayerDataHandler:Unequip(plr, itemName)
	local profile = getProfile(plr) -- Ensure profile is initialized here
	self:Update(plr, "Equipped", function(current)
		print("Unequip - Equipped Before: ", current)
		if table.find(current, itemName) then
			table.remove(current, table.find(current, itemName))
			self:Update(plr, "Inventory", function(inventory)
				table.insert(inventory, itemName)
				print("Unequip - Inventory After: ", inventory)
				return inventory
			end)
		else
			print(plr, "does not have", itemName)
		end
		print("Unequip - Equipped After: ", current)
		return current
	end)
	local item = game.ReplicatedStorage.Assets:FindFirstChild(itemName)
	if not item then return end
end

[urgentnotice]

Seems like now im getting a error that I never encountered before

11:27:11.318  Updating key:  Inventory Old Data Type:  table  ▼  {
                    [1] = "ClassicSword"
                 }  -  Server - PlayerDataHandler:205
  11:27:11.319  Updating key:  Equipped Old Data Type:  table {}  -  Server - PlayerDataHandler:205
  11:27:11.320  New Data Type:  nil nil  -  Server - PlayerDataHandler:208
-- There is a second nil because I made it also print new data itself after it prints the type
  11:27:11.320  New Data Type:  table {}  -  Server - PlayerDataHandler:208
--Above is the equip function output
  11:27:24.352  ServerScriptService.PlayerDataHandler:112: data does not exist for key: Equipped  -  Server -
--This is after I press unequip

[urgentnotice]

Ok for whatever reason it seems to work now after I copy and paste your code and I dont seem to be getting the assertion faield error anymroe so ill mark this as solution