"TrackedValues" is null when sending ClientboundSetEntityDataPacket to client and causes client to crash

[ClayCoffee]

Expected behavior

No exceptions and everything works fine.

Observed/Actual behavior

Exception threw and then the client crashed.

Steps/models to reproduce

1. playing normally with more than one player online in the same region
2. crash

Plugin and Datapack List

BlueMap, BlueMap-Towny, Brewery, Chunky, CMI, CMILib, CoreProtect, FlagWar, floodgate InventoryRollbackPlus, LaggRemover, LuckPerms, NBTAPI, PlaceholderAPI, PlugManX, Scoreboard, SkinsRestorer, TheNewEconomy, Towny, TownyChat, Vault, ViaBackwards, ViaVersion, WorldEdit

Folia version

This server is running Folia version git-Folia-"25ee657" (MC: 1.20.4) (Implementing API version 1.20.4-R0.1-SNAPSHOT) (Git: 25ee657)

Other

[19:29:47 ERROR]: Packet encoding of packet ClientboundSetEntityDataPacket (ID: 86) threw (skippable? false) java.lang.NullPointerException: Cannot invoke "java.util.List.iterator()" because "trackedValues" is null at net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket.pack(ClientboundSetEntityDataPacket.java:17) ~[?:?] at net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket.write(ClientboundSetEntityDataPacket.java:38) ~[?:?] at net.minecraft.network.PacketEncoder.encode(PacketEncoder.java:42) ~[folia-1.20.4.jar:git-Folia-"25ee657"] at net.minecraft.network.PacketEncoder.encode(PacketEncoder.java:14) ~[folia-1.20.4.jar:git-Folia-"25ee657"] at io.netty.handler.codec.MessageToByteEncoder.write(MessageToByteEncoder.java:107) ~[netty-codec-4.1.97.Final.jar:4.1.97.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:881) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:863) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final] at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:968) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final] at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:856) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final] at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:113) ~[netty-codec-4.1.97.Final.jar:4.1.97.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:881) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final] at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:940) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final] at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:966) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final] at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:934) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final] at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:984) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final] at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:1025) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final] at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:306) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final] at net.minecraft.network.Connection.doSendPacket(Connection.java:475) ~[?:?] at net.minecraft.network.Connection.lambda$sendPacket$10(Connection.java:460) ~[?:?] at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:174) ~[netty-common-4.1.97.Final.jar:4.1.97.Final] at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:167) ~[netty-common-4.1.97.Final.jar:4.1.97.Final] at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:470) ~[netty-common-4.1.97.Final.jar:4.1.97.Final] at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:569) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final] at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997) ~[netty-common-4.1.97.Final.jar:4.1.97.Final] at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.97.Final.jar:4.1.97.Final] at java.lang.Thread.run(Thread.java:842) ~[?:?] (Player xxx left the game)

[ClayCoffee]

Client version: 1.20.4

[ClayCoffee]

Looks like it might be a problem with LaggRemover.

[ClayCoffee]

UPDATE: It happens occasionally even with LaggRemover removed.

[electronicboy]

There comes a level of "it's very unlikely to be folia inducing this", if you know what you're doing, modify the constructor for that class to throw an exception if null is passed in instead of actual data

[ClayCoffee]

There comes a level of "it's very unlikely to be folia inducing this", if you know what you're doing, modify the constructor for that class to throw an exception if null is passed in instead of actual data

ok im trying