JSON file loading crash

Questions
#1

Hello. I am trying to access a json file here which will store the highscores for my game. This bit of code here is so I can access the file and I will make it so the high score is displayed on the title screen.

 local json = require("json")

local function loadHighscore(filename)
	local content = sys.load(filename)
	if content == nil then
		print("Failed to load JSON content from file: " .. filename)
		return nil
	end

	local success, data = pcall(json.decode, content)
	if not success or not data or not data.numbers then
		print("Invalid or missing data in JSON file: " .. filename)
		return nil
	end

	table.sort(data.numbers, function(a, b) return a > b end)

	--Return the highest score (first value)
	return data.numbers[1]
end

function init(self)
	self.file_path = sys.get_save_file("main", "test.json")
	local highscore = loadHighscore(self.file_path)
end

I have accessed the json file using the same method in another script to sort the data however when this script runs it crashes. This is what the console reads:

image
image1699×674 222 KB

Why is this happening?

#2

Is your test.json file created by sys.save() or just your plain json string file?

#3

I’m not too sure. I think it’s done through sys.save(). Should I attatch the other script so you can see what’s happening there?

#4

When saving and loading using sys.save(), sys.load(), you don’t need to decode it because it is already parsed to a lua table.

#5

I have changed the script so it is not decoding but it is still crashing unfortunately

local function loadHighscore(filename)
	local content = sys.load(filename)
	if content == nil then
		print("Failed to load JSON content from file: " .. filename)
		return nil
	end

	local data = content
	if not data or not data.numbers then
		print("Invalid or missing data in JSON file: " .. filename)
		return nil
	end

	table.sort(data.numbers, function(a, b) return a > b end)

	-- Return the highest score (first value)
	return data.numbers[1]
end

function init(self)
	self.file_path = sys.get_save_file("main", "test.json")
	local highscore = loadHighscore(self.file_path)
end
#6

I think your file is not created by sys.save(). Can you show me where you save it?

#7

Like the file address or where I save it in the script?

#8

Where in your code

#9

Not sure if this exactly what you meant but here is code where stuff is written to the file.

local function writeJSONToFile(file_path, data)
	local file = io.open(file_path, "w")
	if not file then
		print("Failed to open JSON file for writing")
		return
	end
	file:write(json.encode(data))
	file:close()
end
#10

Generally, the sys.save() will save a lua table to file and sys.load() will load that file to a lua table. You don’t need to encode or decode your data

#11

You just need to use sys.save in that place, do not encode your table. Or if you use io. file write then use io. file:read then

1 Like
#12

Like this?

local function saveDataToFile(file_path, data)
	local success = sys.save(file_path, data)
	if not success then
		print("Failed to save data to file: " .. file_path)
	end
end
1 Like
#13

I still get the same crash

#14

You can go to the saved file location to check. I think your old file is still there. If yes, delete it and try again. Also make sure the file path is correct

1 Like
#15

We’d like to look into this! Can you please create a ticket on GitHub and share a minimal project where the crash happens.

1 Like
#16

I can’t get the crash to trigger again unfortunately and I can’t figure out why, can I zip up my project and put it here?

#17

Oh, ok, if it is not crashing anymore there’s probably not much point to share the project. Let us know if it crashes.

#18

No I mean my main project is crashing still but in the new minimal project I cannot replicate the crash. Sorry for the confusion.

#19

Ok, are you able to share it (you can share it with me, bjorn@defold.se)

#20

I have emailed you it now.