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Drathonix / LoadMyChunks

A server friendly chunk loading mod
MIT License
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[CONFLICT] Concurrent Chunk Management Engine #12

Closed Drathonix closed 3 days ago

Drathonix commented 5 days ago

Encountered originally in #3, CCME causes a conflict with the FastUtil rehash function for our chunk data manager.

// Who set us up the TNT?

Time: 2024-06-25 08:53:49
Description: Exception chunk generation/loading

java.lang.ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 65
    at it.unimi.dsi.fastutil.longs.Long2ObjectLinkedOpenHashMap.rehash(Long2ObjectLinkedOpenHashMap.java:1809)
    at it.unimi.dsi.fastutil.longs.Long2ObjectLinkedOpenHashMap.insert(Long2ObjectLinkedOpenHashMap.java:315)
    at it.unimi.dsi.fastutil.longs.Long2ObjectLinkedOpenHashMap.computeIfAbsent(Long2ObjectLinkedOpenHashMap.java:782)
    at com.vicious.loadmychunks.common.system.ChunkDataManager$LevelChunkLoaderManager.getOrCreateData(ChunkDataManager.java:217)
    at com.vicious.loadmychunks.common.system.ChunkDataManager$LevelChunkLoaderManager.getOrCreateData(ChunkDataManager.java:189)
    at com.vicious.loadmychunks.common.system.ChunkDataManager.getOrCreateChunkData(ChunkDataManager.java:132)
    at MC//net.minecraft.world.chunk.WorldChunk.handler$die000$loadmychunks$setup(WorldChunk.java:4791)
    at MC//net.minecraft.world.chunk.WorldChunk.<init>(WorldChunk.java:111)
    at MC//net.minecraft.world.ChunkSerializer.deserialize(ChunkSerializer.java:166)
    at MC//net.minecraft.server.world.ServerChunkLoadingManager.md3d23ee$c2me-threading-chunkio$lambda$c2me$loadChunk0$5$1a(ServerChunkLoadingManager.java:8944)
    at java.base@21.0.3/java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:646)
    at java.base@21.0.3/java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:482)
    at com.ishland.c2me.base.common.scheduler.WrappingTask.run(WrappingTask.java:21)
    at com.ishland.flowsched.executor.WorkerThread.pollTasks(WorkerThread.java:56)
    at com.ishland.flowsched.executor.WorkerThread.run(WorkerThread.java:27)
ishland commented 5 days ago

The async serialization system in C2ME expects the ChunkSerializer#deserialize and ChunkSerializer#serialize to be parallel capable. MixinWorldChunk#setup break this assumption and therefore it is crashing there since it is not parallel capable.

The easiest way to solve this is to synchronize ChunkDataManager$LevelChunkLoaderManager#data and ChunkDataManager#levelManagers.

Drathonix commented 5 days ago

The async serialization system in C2ME expects the ChunkSerializer#deserialize and ChunkSerializer#serialize to be parallel capable. MixinWorldChunk#setup break this assumption and therefore it is crashing there since it is not parallel capable.

The easiest way to solve this is to synchronize ChunkDataManager$LevelChunkLoaderManager#data and ChunkDataManager#levelManagers.

You know whats funny, I already patched this in an alpha but I completely forgot about the "sychronized" modifier 🤦 . I'll make sure to undo my stupid and apply the smart.

Drathonix commented 3 days ago

Fixed in 1.0.5