`java.lang.IndexOutOfBoundsException` from `com.BrassAmber.ba_bt.util.BTLoot.fillPool`

[ASchneider-GitHub]

Describe the bug Server is crashing after tick is taking 60 seconds to complete as shown in the error message from the crash report:

java.lang.Error: ServerHangWatchdog detected that a single server tick took 60.00 seconds (should be max 0.05)
    at net.minecraft.server.dedicated.ServerWatchdog.run(ServerWatchdog.java:45) [server-1.18.2-20220404.173914-srg.jar%23332!/:?] {re:classloading}
    at java.lang.Thread.run(Thread.java:1589) [?:?] {re:mixin}

When reviewing the debug server logs, it looks like the issue is the function that handles generating loot pools

net.minecraft.ReportedException: Ticking entity
    at net.minecraft.server.MinecraftServer.m_5703_(MinecraftServer.java:906) ~[server-1.18.2-20220404.173914-srg.jar%23332!/:?]
    at net.minecraft.server.dedicated.DedicatedServer.m_5703_(DedicatedServer.java:326) ~[server-1.18.2-20220404.173914-srg.jar%23332!/:?]
    at net.minecraft.server.MinecraftServer.m_5705_(MinecraftServer.java:842) ~[server-1.18.2-20220404.173914-srg.jar%23332!/:?]
    at net.minecraft.server.MinecraftServer.m_130011_(MinecraftServer.java:685) ~[server-1.18.2-20220404.173914-srg.jar%23332!/:?]
    at net.minecraft.server.MinecraftServer.m_177918_(MinecraftServer.java:261) ~[server-1.18.2-20220404.173914-srg.jar%23332!/:?]
    at java.lang.Thread.run(Thread.java:1589) [?:?]
Caused by: java.lang.IndexOutOfBoundsException: Index 26 out of bounds for length 26
    at jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:100) ~[?:?]
    at jdk.internal.util.Preconditions.outOfBoundsCheckIndex(Preconditions.java:106) ~[?:?]
    at jdk.internal.util.Preconditions.checkIndex(Preconditions.java:302) ~[?:?]
    at java.util.Objects.checkIndex(Objects.java:385) ~[?:?]
    at java.util.ArrayList.get(ArrayList.java:427) ~[?:?]
    at com.BrassAmber.ba_bt.util.BTLoot.fillPool(BTLoot.java:213) ~[BrassAmberBattleTowers-1.18.2-2.3.12.jar%2390!/:1.18.2-2.3.12]
    at com.BrassAmber.ba_bt.util.BTLoot.getLootTableBuilder(BTLoot.java:285) ~[BrassAmberBattleTowers-1.18.2-2.3.12.jar%2390!/:1.18.2-2.3.12]
    at com.BrassAmber.ba_bt.util.BTLoot.getLootTable(BTLoot.java:261) ~[BrassAmberBattleTowers-1.18.2-2.3.12.jar%2390!/:1.18.2-2.3.12]
    at com.BrassAmber.ba_bt.entity.block.BTAbstractObelisk.checkSpawners(BTAbstractObelisk.java:491) ~[BrassAmberBattleTowers-1.18.2-2.3.12.jar%2390!/:1.18.2-2.3.12]
    at com.BrassAmber.ba_bt.entity.block.BTAbstractObelisk.m_8119_(BTAbstractObelisk.java:354) ~[BrassAmberBattleTowers-1.18.2-2.3.12.jar%2390!/:1.18.2-2.3.12]
    at net.minecraft.server.level.ServerLevel.m_8647_(ServerLevel.java:652) ~[server-1.18.2-20220404.173914-srg.jar%23332!/:?]
    at net.minecraft.world.level.Level.m_46653_(Level.java:5079) ~[server-1.18.2-20220404.173914-srg.jar%23332!/:?]
    at net.minecraft.server.level.ServerLevel.m_184063_(ServerLevel.java:319) ~[server-1.18.2-20220404.173914-srg.jar%23332!/:?]
    at net.minecraft.world.level.entity.EntityTickList.m_156910_(EntityTickList.java:54) ~[server-1.18.2-20220404.173914-srg.jar%23332!/:?]
    at net.minecraft.server.level.ServerLevel.m_8793_(ServerLevel.java:299) ~[server-1.18.2-20220404.173914-srg.jar%23332!/:?]
    at net.minecraft.server.MinecraftServer.m_5703_(MinecraftServer.java:902) ~[server-1.18.2-20220404.173914-srg.jar%23332!/:?]
    ... 5 more

Function in question: https://github.com/BrassAmber-Mods/Brass_Amber_BattleTowers/blob/1.18.2-Version/src/main/java/com/BrassAmber/ba_bt/util/BTLoot.java#L202

To Reproduce Things needed to reproduce the behavior: (Replace with your answer) Unfortunately I'm not sure what exactly is triggering this crash, but my guess is that there's a loot container somewhere causing problems. The crash is happening on a server running an unmodified version of the CRIF2 modpack.

Attached Files

• Server debug logs
• Full-length crash report

[ASchneider-GitHub]

If the issue is related to a specific loot container, I can try removing the chunk from the world file and regenerating it, but unfortunately I'm not sure how to track down the specific chunk that has the problematic chest.

[JMilamber]

Just realized I fixed this and never answered the Issue here:

This turned out to be because of a Bukkit mixin that overwrote a function we were using to build the loot item lists and put them in the chests.

Was fixed in commit 0058d44b90dbe98de29143a8f0328b555a33ac30

I think you may have seen this in the update notes when it happened, but updating this Issue anyways.