1.20.1 1.20.1 Crash on Game Load, Config issue?

[HeyKatu]

Hi! Periodically I'm getting this crash: https://gist.github.com/katubug/2f6110323fb879df3520db1043f86faa
I'm using Forge 47.2.17

Here's the main line, to help people searching for this error:

java.lang.RuntimeException: java.util.concurrent.ExecutionException: java.lang.NullPointerException: Cannot invoke "java.lang.Boolean.booleanValue()" because the return value of "net.minecraftforge.fml.loading.FMLConfig$ConfigValue.getConfigValue(com.electronwill.nightconfig.core.file.CommentedFileConfig)" is null

The crash happens sporadically, and deleting the configs seems to fix it. Or maybe just me relaunching fixes it, but I've usually deleted the configs because that seemed to be the cause. However, I haven't made any changes to the configs and I'm concerned about people experiencing this crash once I release my modpack,  so if possible I'd like to find a solution before I go live with it.

[Paint_Ninja]

This is a known rare issue with the config lib Forge uses, caused by concurrent modification. The author of NightConfig has been made aware and we're waiting on a fix from them.

The bug triggers more often when config files are left open in editors while the game is launching or running, or multiple instances of the game are started, however it can unfortunately also happen at random without doing either of those things.

Edited December 18, 2023 by Paint_Ninja

[HeyKatu]

Oh, that makes a lot of sense! I've basically always got a handful of config files open in vscode when I restart because I'm developing a modpack. I'll keep that in mind, but it's good to know it'll be a rare occurrence for the end user. Hopefully a fix can be worked out! Thank you for your help!