[Bug]: Random world deadlock on NEARBY_PLAYERS_MEAN calculation

[KabanFriends]

Mod Version

0.9.5

Hytale Version

2026.02.06-aa1b071c2

Describe the bug

Worlds seem to randomly end up in a deadlock situation when using LevelingCore. The stacktrace is observed using a custom thread dumper:

[2026/02/09 19:00:00 SEVERE]                        [Watchdog] Thread: WorldThread - default (ID: 159):
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at java.base@25.0.1/jdk.internal.misc.Unsafe.park(Native Method)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at java.base@25.0.1/java.util.concurrent.locks.LockSupport.park(LockSupport.java:223)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at java.base@25.0.1/java.util.concurrent.CompletableFuture$Signaller.block(CompletableFuture.java:1885)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at java.base@25.0.1/java.util.concurrent.ForkJoinPool.unmanagedBlock(ForkJoinPool.java:4364)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at java.base@25.0.1/java.util.concurrent.ForkJoinPool.managedBlock(ForkJoinPool.java:4310)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at java.base@25.0.1/java.util.concurrent.CompletableFuture.waitingGet(CompletableFuture.java:1919)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at java.base@25.0.1/java.util.concurrent.CompletableFuture.join(CompletableFuture.java:2138)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at com.hypixel.hytale.server.core.universe.world.World.getPlayers(World.java:751)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at ThirdPartyPlugin//com.azuredoom.levelingcore.utils.MobLevelingUtil.computeNearbyPlayersMeanLevel(MobLevelingUtil.java:136)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at ThirdPartyPlugin//com.azuredoom.levelingcore.utils.MobLevelingUtil.lambda$computeDynamicLevel$0(MobLevelingUtil.java:46)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at ThirdPartyPlugin//com.azuredoom.levelingcore.utils.MobLevelingUtil$$Lambda/0x00000000273a7000.apply(Unknown Source)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at java.base@25.0.1/java.util.Optional.map(Optional.java:260)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at ThirdPartyPlugin//com.azuredoom.levelingcore.utils.MobLevelingUtil.computeDynamicLevel(MobLevelingUtil.java:42)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at ThirdPartyPlugin//com.azuredoom.levelingcore.systems.level.MobLevelSystem.lambda$drainPending$0(MobLevelSystem.java:136)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at ThirdPartyPlugin//com.azuredoom.levelingcore.systems.level.MobLevelSystem$$Lambda/0x00000000273a5c00.run(Unknown Source)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at com.hypixel.hytale.server.core.universe.world.World.consumeTaskQueue(World.java:904)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at com.hypixel.hytale.server.core.universe.world.World.tick(World.java:419)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at com.hypixel.hytale.server.core.util.thread.TickingThread.run(TickingThread.java:89)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at java.base@25.0.1/java.lang.Thread.runWith(Thread.java:1487)
[2026/02/09 19:00:46 SEVERE]                        [Watchdog]     at java.base@25.0.1/java.lang.Thread.run(Thread.java:1474)

Specifically, the line of interest is MobLevelingUtil.java:136 where it calls World#getPlayers. Calling this from a non-world thread may result in the world freezing, but it is currently unknown under what situation this is invoked from a non-world thread.

To Reproduce

1. Steps unknown, currently investigating...

[KabanFriends]

I'm trying to clean up parts of the code in the hopes of fixing the issue, but it's really unclear what exactly is wrong here. I can share the branch as a PR if you want to help.

Currently I'm removing some of the World#execute scheduling around MobLevelSystem as I think you shouldn't need a lot of them inside a system for the same world

[AzureDoom]

Hmm yeah this is an odd one, if you wanna throw up a draft pr with your work, I can poke in as well!

[AzureDoom]

I think I should move to use chunks instead to get players instead of all the players in the world similar to how i do nameplates. Hmm will test here tomorrow with a massive overhaul as I want to support level ranges as well.

[AzureDoom]

Based on some feedback from other devs in the community, looks like this is a Hytale bug more than a bug with levelingcore itself and is known by the devs but no ETA on a fix yet. Suggestion was to try adding Djava.util.concurrent.ForkJoinPool.common.parallelism=16 to your servers launch parms if possible. It's not a complete fix but a stop gap until fixed Hytale side.