Mob Spawners do not render a "mini" mob visual for the following entities:
Bee
Enderman
Polar Bear
Wolf
Zombified Piglin
Evoker Fangs
See attached images for expected (Elder Guardian) vs unexpected (Zombified Piglin). When the game attempts to render them but fails, it also produces an error message in the console over and over again, which can potentially cause a lot of lag in the world, especially when lots of spawners are used.
[01:00:15] [Render thread/WARN]: Exception loading entity:
s: Loading entity NBT
at aol.f(SourceFile:1642) ~[1.16-pre5.jar:?]
at aop.a(SourceFile:467) ~[1.16-pre5.jar:?]
at aop$$Lambda$4201/93583133.accept(Unknown Source) ~[?:?]
at v.a(SourceFile:401) ~[1.16-pre5.jar:?]
at aop.a(SourceFile:466) ~[1.16-pre5.jar:?]
at aop.b(SourceFile:529) [1.16-pre5.jar:?]
at aop.a(SourceFile:510) [1.16-pre5.jar:?]
at bpc.d(SourceFile:256) [1.16-pre5.jar:?]
at eei.a(SourceFile:22) [1.16-pre5.jar:?]
at eei.a(SourceFile:12) [1.16-pre5.jar:?]
at edw.a(SourceFile:107) [1.16-pre5.jar:?]
at edw.b(SourceFile:96) [1.16-pre5.jar:?]
at edw$$Lambda$4990/1816104835.run(Unknown Source) [1.16-pre5.jar:?]
at edw.a(SourceFile:128) [1.16-pre5.jar:?]
at edw.a(SourceFile:96) [1.16-pre5.jar:?]
at ebx.a(SourceFile:1236) [1.16-pre5.jar:?]
at ebs.a(SourceFile:717) [1.16-pre5.jar:?]
at ebs.a(SourceFile:540) [1.16-pre5.jar:?]
at dlx.e(SourceFile:1021) [1.16-pre5.jar:?]
at dlx.d(SourceFile:654) [1.16-pre5.jar:?]
at net.minecraft.client.main.Main.main(SourceFile:215) [1.16-pre5.jar:?]
Caused by: java.lang.ClassCastException: dym cannot be cast to zc
at ayk.a(SourceFile:260) ~[1.16-pre5.jar:?]
at aol.f(SourceFile:1633) ~[1.16-pre5.jar:?]
... 20 moreWhat I expected to happen was...:
A "mini" version of the mob to be rendered in the middle of the spawner cube.
What actually happened was...:
No "mini" version of the mob is rendered inside the cage.
Steps to Reproduce:
Place down a spawner
Modify the spawner's block data to the desired mob (can be done through commands or by right-clicking on the cage with the desired mob spawn egg).
Note: The spawner does spawn the desired mob. The issue is only visual – you cannot tell what kind of spawner it is just by looking at it.
Code analysis
See this comment.
Linked issues
relates to 1
Attachments
Comments 13
Well, this bug appears for all mobs that have their readAdditionalSaveData(CompoundTag) method overriden + a call to readPersistentAngerSaveData which casts the Level to a ServerLevel. As renderers are client sided executing this method's code causes a ClassCastException (ClientLevel cannot be cast to ServerLevel).
A simple server side check should fix the bug.
@Algeseven – could you possibly clarify in which class the server-side check needs to be implemented? I've been patiently waiting for a fix for this but it seems like we're not getting one until 1.17 which is unacceptable in my opinion. I'm trying to create a patch to fix this myself as some features on my server depend on some of these spawners, and I'm having trouble determining where this check should go. Thanks in advance.
This bug still affects release 1.16.4 (vanilla client and server) using the following custom spawner:
/setblock ~ ~-1 ~ minecraft:spawner\{SpawnData:{id:iron_golem},SpawnCount:3,SpawnRange:4,RequiredPlayerRange:25,Delay:20,MinSpawnDelay:9600,MaxSpawnDelay:9600,MaxNearbyEntities:25} replaceSpamming the client logs with thousands of warnings about:
Exception loading entity: u: Loading entity NBT at aqa.f(SourceFile:1663) at aqe.a(SourceFile:473) at x.a(SourceFile:402) at aqe.a(SourceFile:472) at aqe.b(SourceFile:535) at aqe.a(SourceFile:516) at bqz.d(SourceFile:254) at ecp.a(SourceFile:22) at ecp.a(SourceFile:12) at ecd.a(SourceFile:107) at ecd.b(SourceFile:96) at ecd.a(SourceFile:128) at ecd.a(SourceFile:96) at eae.a(SourceFile:1260) at dzz.a(SourceFile:727) at dzz.a(SourceFile:546) at djz.e(SourceFile:1048) at djz.e(SourceFile:681) at net.minecraft.client.main.Main.main(SourceFile:215) Caused by: java.lang.ClassCastException: class dwt cannot be cast to class aag (dwt and aag are in unnamed module of loader 'app') at bai.a(SourceFile:170) at aqa.f(SourceFile:1654) ... 18 moreAs a consequence, user logs can grow very large.
Confirmed, also the log is spammed with this: