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  1. Minecraft: Java Edition
  2. MC-215120

World-gen datapacks can cause crashes when first generating world


    • Icon: Bug Bug
    • Resolution: Fixed
    • 21w14a
    • 21w06a, 21w07a
    • None
    • Confirmed
    • Crash, Custom Worlds
    • Very Important

      The bug

      I am trying to update a world-gen datapack from 21w05a to 21w06a. In doing so I need to load said datapack into a new world. However, the game crashes as soon as the game starts generating chunks.

      How to reproduce

      1. Create a new world
      2. Add this datapack during world creation
      3. Begin generating the world
      4. Observe crash

      Stack trace

      Description: Exception generating new chunk
      java.lang.ArrayIndexOutOfBoundsException: 247
      	at cme.a(SourceFile:146)
      	at cmq.a(SourceFile:246)
      	at cmq.a(SourceFile:224)
      	at cmq.a(SourceFile:162)
      	at cpz$a.a(SourceFile:123)
      	at cpz$a.a(SourceFile:62)
      	at cqk.a(SourceFile:268)
      	at cnz.a(SourceFile:36)
      	at cjo.a(SourceFile:294)
      	at cjo.a(SourceFile:277)
      	at cjq.e(SourceFile:53)
      	at cjq.a(SourceFile:231)
      	at aai.a(SourceFile:563)
      	at com.mojang.datafixers.util.Either$Left.map(Either.java:38)
      	at aai.a(SourceFile:557)
      	at java.util.concurrent.CompletableFuture.uniCompose(CompletableFuture.java:952)
      	at java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:926)
      	at java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:442)
      	at aak.b(SourceFile:58)
      	at apb.e(SourceFile:84)
      	at apb.a(SourceFile:124)
      	at apb.run(SourceFile:92)
      	at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1402)
      	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
      	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
      	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)

            panda4994 [Mojang] Panda
            Starmute Starmute
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