When I try to start a modpack, it starts up, but immediately stops without any logs except for this:

[08:15:43] [main/INFO]:ModLauncher running: args [--username, Lightning3223, --version, forge-47.3.12, --gameDir, ..., --assetsDir, .., --assetIndex, 5, ... --userType, msa, --versionType, release, --width, 1920, --height, 1080, , , , , --launchTarget, forgeclient, --fml.forgeVersion, 47.3.12, --fml.mcVersion, 1.20.1, --fml.forgeGroup, net.minecraftforge, --fml.mcpVersion, 20230612.114412]

[08:15:43] [main/INFO]:ModLauncher 10.0.9+10.0.9+main.dcd20f30 starting: java version 17.0.8 by Eclipse Adoptium; OS Windows 11 arch amd64 version 10.0

(Yes I did try reinstalling forge and the same issue persists)

The reason forge wont start is due to the NAME OF one of the mods (the jarfile): northstar-true-north-1.1.0.jar

What fixed it for me was renaming the mod to something else like "test"

This is a bug with forge and a pretty serious one at that, considering I wouldn't have known it was the name of a mod that caused my game to not even start.

This is a serious problem among things like curseforge because you can't just rename mods if you're downloading a modpack.

I am not sure, but I think I read about a similar case where the issue was a specific word in the mod file name - here in this case it is "true"

This has something to with mod loading behavior

 

Rename it to northstar-north-1.1.0.jar and it will work

If you rename it to true.jar or true-1.1.0.jar, the game will crash - even if you name it false.jar

I am not that deep into mod developing - but I think this is some kind of "expecting String instead of Boolean value" syntax issue somewhere deep in the modloading process (mixin configs, metadata, class scanning etc.)

So I think this is some kind of Java issue, not Forge itself 🤔