Bug Description

Running 1.20.1, Forge 47.2.18, Modernfix 5.18.1, Distant horizons 2.1.2.a

For context i have pregenerated the world with chunky then started pregenerating distant lod data using DH's distant generation, it had been doing well for a few hours, even reached the worldborder in some points (i set it to 5000 and pregenerated everything inside the border)

Then seemingly randomly the game crashed with Cannot invoke "it.unimi.dsi.fastutil.longs.LongArrayList.getLong(int)" because "this.wrapped" is null, for context this is all in singleplayer

after this everytime id load into the world (DH still working) it would crash after a few moments, if i had to guess it would be DH spawning pregen threads (it's very aggressive when set to the highest setting) and messing with fastutil, seems related to #446

what puzzles me is that it had been generating thousands of chunks of LOD data and the logs dont seem to point out a specific issue

Removing modernfix fixes the crash

Reproduction Steps

Create New world, disable DH rendering and distant generation
Set Worldborder to 5000
Pregenerate 2500 block radius with chunky
Enable distant horizons and enable distant generation, medium quality, i paid for the whole cpu preset
wait and Trust me bro™

Log File

crash-2024-08-02_20.25.12-server.txt
latest.log
modlist.txt
debug(1).log

big if true

Same issue in 1.21, have had no issue after removing the mod.
Seems to be true

There are very few optimizations in ModernFix that touch chunk generation scheduling, I suspect this is a DH issue. However, you can try disabling mixin.bugfix.paper_chunk_patches in the ModernFix config and see if it makes a difference.

Might instead be related to the cache upgrade mixin? Every time it kicks in the debug, everything goes to a crawl with DH:

[Worker-Main-10/DEBUG] [ModernFix/]: Using cached upgraded version of nova_structures:wild_ruin/wild_ruin_1

If that were the case, it would not affect 1.21 users, as the structure upgrade cache feature was removed in that version.

Had this error too on 1.21
Cannot invoke "it.unimi.dsi.fastutil.longs.LongArrayList.getLong(int)" because "this.wrapped" is null
but I didn't have ModernFix installed. It was a different issue, maybe even DH related. If i recall correctly, deleting the LODs in the world save folder and then re-generating them fixed it