LegacyRandomSource crash from Botania mixin

[purejosh]

Mod Loader

Forge

Minecraft Version

1.20.1

Botania version

1.20.1-446-FORGE

Modloader version

47.3.7

Modpack info

No response

The latest.log file

https://gist.github.com/purejosh/7c044fd9ef9b89e839f3149a5c0e59c0

Issue description

Server randomly crashes with this log.

Steps to reproduce

No response

Other information

No response

[TheRealWormbo]

May I ask why you reported this here? The log seems to suggest a different mod's mixin. Botania just happens to be present, and is not the only mod "involved" either.

[purejosh]

If there's a mixin conflict, why would I only report it to one person? Understanding the mixin and what may conflict with it needs more than one perspective. I'm not sure why you're questioning this report.

[TheRealWormbo]

Here's what I read out of the crash stack trace:

• ThreadingDetector, a vanilla class used in LegacyRandomSource (another vanilla class), creates an exception with the intention of crashing things due to an illegal state.
• The illegal state is that NaturalSpawner (yet another vanilla class, responsible for natural mob spawning) accessed the random source concurrently with some other code.
• The call stack traces back to the usual place where natural mob spawning would happen.
• Botania's mixins to mob spawning do not access randomness and certainly (being mixins) do not move that functionality off the main thread.

What you are seeing here is vanilla code reacting to something else accessing the random source concurrently. Whatever that "something" is, it shouldn't be doing that. Botania was present in the general area of code that detected the illegal random source state, but it was not involved in either the detection or the creation of said invalid state.

As far as I can tell, this is not a mixin conflict, but some completely unrelated code that ran in another thread at the time the main thread attempted to generate randomness for vanilla mob spawning logic.