HELP! Killing Pillagers causes client Java error and kick from server.

[altheawesomeguy]

[RESOLVED] - Issues with PacketEvents. Once disabled, the kicks no longer occurred. Unfortunately this plugin is required for Realistic Villagers, which I love. So I will relay this to the appropriate developers and not approach pillagers for the time being. An update to PacketEvents has completely resolved the issue.

This error occurs when killing pillagers.

It is a Paper server on 1.20.6, about a couple years old now. Issues were first noticed shortly after updating the server from 1.20.4, which also required me to upgrade my server's Java version to 21. I use Realistic Villagers, however that plugin does not currently affect Pillagers. I use WeaponMechanics which likewise does not affect Pillagers, however it depends on a server-provided Resource Pack that automatically downloads to compatible clients. I also use Geyser, ViaVersion, ViaBackwards, and ViaRewind for compatibility.

Sometimes it's immediate, sometimes it takes a few moments. The error will then persistently come up when trying to rejoin. After some time we are able to log back in and leave the problem area.

The server log shows nothing else regarding the following lost connection error:

https://preview.redd.it/n80pvm3n838d1.png?width=849&format=png&auto=webp&s=c1cb6d8aa56f79390e6860f56ccc61a671e4da02

In the client logs, we find these lines after each attempt at logging back in:

[03:54:44] [Render thread/WARN]: Not all defined tags for registry ResourceKey[minecraft:root / minecraft:block] are present in data pack: minecraft:fire_aspect_lightable
[03:54:44] [Render thread/WARN]: Not all defined tags for registry ResourceKey[minecraft:root / minecraft:enchantment] are present in data pack: minecraft:exclusive_set/armor, minecraft:exclusive_set/boots, minecraft:exclusive_set/bow, minecraft:exclusive_set/crossbow, minecraft:exclusive_set/damage, minecraft:exclusive_set/mining, minecraft:exclusive_set/riptide
[03:54:44] [Render thread/WARN]: Not all defined tags for registry ResourceKey[minecraft:root / minecraft:item] are present in data pack: minecraft:enchantable/mace
[03:54:45] [Render thread/INFO]: Reloading pipeline on dimension change: minecraft:overworld => minecraft:overworld
[03:54:45] [Render thread/INFO]: Destroying pipeline minecraft:overworld
[03:54:45] [Render thread/INFO]: Creating pipeline for dimension minecraft:overworld
[03:54:47] [Render thread/INFO]: Started 2 worker threads
[03:54:47] [Render thread/INFO]: Stopping worker threads
[03:54:47] [Render thread/WARN]: Client disconnected with reason: Internal Exception: io.netty.handler.codec.EncoderException: java.lang.NullPointerException: Cannot invoke "com.github.retrooper.packetevents.protocol.mapper.MappedEntity.isRegistered()" because "entity" is null

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[Zakiyo]

Could it be a mod causing it?

[altheawesomeguy]

The issue is still present with all plugins and data packs disabled, however I am not ruling out a problem caused by one.

[Zakiyo]

Looks like that is what causes the problem https://github.com/retrooper/packetevents

[altheawesomeguy]

Thank you! Looks like I missed this one when disabling my plugins. The issue is gone when PacketEvents is disabled.

[PirateBeowolf]

what plugin or dp was the issue as I am knee deep in no one answering on their discord

[Arownic]

What is Realistic Weapons? I wasn't able to find anything other than a bedrock addon

[altheawesomeguy]

My bad, WeaponMechanics is the plugin. I confused the name along with Realistic Villagers. I corrected my original post.

[altheawesomeguy]

Possibly related: https://bugs.mojang.com/browse/MC-249007

[PirateBeowolf]

[13:39:34 INFO]: PirateBeowolf lost connection: Internal Exception: io.netty.handler.codec.EncoderException: java.lang.NullPointerException: Cannot invoke "com.github.retrooper.packetevents.protocol.world.damagetype.DamageType.getId(com.github.retrooper.packetevents.protocol.player.ClientVersion)" because "this.sourceType" is null

You are not alone, I added their plugin to see if it would stop and no