The following is the command in question:
/summon leash_knot ~ ~ ~ {Passengers:[{id:Zombie}]}DO NOT USE ON VALUED WORLD
After running this command once, the game will crash. When you re-enter the world and run the same command, the game will crash again but also delete your world (the level.dat file)
Unfortunately this happened to me on a valuable world and so I lost that world. It was also stupid of me not to make any back-ups, but it was only one of the first nights I was working on it, and I shouldn't have to rely on making back-ups.
I believe the problem is when the LeashKnot naturally despawns, the passengers 'pop-off' and cause issues. In both cases, the timing of the crash after spawning seems to be consistent with the lifetime of the LeashKnot.
java.lang.NullPointerException: Ticking entity
at sa.A(SourceFile:1287)
at sa.p(SourceFile:1834)
at rr.aw(SourceFile:1498)
at sa.aw(SourceFile:1840)
at aht.a(SourceFile:1513)
at lp.a(SourceFile:719)
at aht.g(SourceFile:1493)
at aht.a(SourceFile:1559)
at lp.a(SourceFile:719)
at aht.g(SourceFile:1493)
at aht.k(SourceFile:1383)
at lp.k(SourceFile:552)Code analysis by @unknown can be found in this comment.
Linked issues
is duplicated by 1
Attachments
Comments 17
Confirmed for 1.9.1-pre3.
Crash report (1.9.1-pre3)
---- Minecraft Crash Report ----
// Shall we play a game?
Time: 25/03/16 3:11 PM
Description: Ticking entity
java.lang.NullPointerException: Ticking entity
at sa.A(SourceFile:1291)
at sa.p(SourceFile:1838)
at rr.aw(SourceFile:1498)
at sa.aw(SourceFile:1844)
at aht.a(SourceFile:1514)
at lp.a(SourceFile:717)
at aht.g(SourceFile:1494)
at aht.a(SourceFile:1560)
at lp.a(SourceFile:717)
at aht.g(SourceFile:1494)
at aht.k(SourceFile:1384)
at lp.k(SourceFile:550)
at net.minecraft.server.MinecraftServer.D(SourceFile:625)
at net.minecraft.server.MinecraftServer.C(SourceFile:553)
at byl.C(SourceFile:154)
at net.minecraft.server.MinecraftServer.run(SourceFile:457)
at java.lang.Thread.run(Thread.java:745)
A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------
-- Head --
Stacktrace:
at sa.A(SourceFile:1291)
at sa.p(SourceFile:1838)
at rr.aw(SourceFile:1498)
at sa.aw(SourceFile:1844)
at aht.a(SourceFile:1514)
at lp.a(SourceFile:717)
at aht.g(SourceFile:1494)
at aht.a(SourceFile:1560)
at lp.a(SourceFile:717)
at aht.g(SourceFile:1494)
-- Entity being ticked --
Details:
Entity Type: LeashKnot (xt)
Entity ID: 24712
Entity Name: entity.LeashKnot.name
Entity's Exact location: 324.50, 4.50, 1160.50
Entity's Block location: World: (324,4,1160), Chunk: (at 4,0,8 in 20,72; contains blocks 320,0,1152 to 335,255,1167), Region: (0,2; contains chunks 0,64 to 31,95, blocks 0,0,1024 to 511,255,1535)
Entity's Momentum: 0.00, 0.00, 0.00
Entity's Passengers: []
Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
at aht.k(SourceFile:1384)
at lp.k(SourceFile:550)
-- Affected level --
Details:
Level name: EEK! World corruptor bug test!
All players: 1 total; [lr['__null'/32, l='EEK! World corruptor bug test!', x=328.12, y=4.00, z=1160.03]]
Chunk stats: ServerChunkCache: 1090 Drop: 0
Level seed: 1006927368700508016
Level generator: ID 01 - flat, ver 0. Features enabled: true
Level generator options:
Level spawn location: World: (320,4,1168), Chunk: (at 0,0,0 in 20,73; contains blocks 320,0,1168 to 335,255,1183), Region: (0,2; contains chunks 0,64 to 31,95, blocks 0,0,1024 to 511,255,1535)
Level time: 230 game time, 230 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 68666 (now: false), thunder time: 142322 (now: false)
Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
at net.minecraft.server.MinecraftServer.D(SourceFile:625)
at net.minecraft.server.MinecraftServer.C(SourceFile:553)
at byl.C(SourceFile:154)
at net.minecraft.server.MinecraftServer.run(SourceFile:457)
at java.lang.Thread.run(Thread.java:745)
-- System Details --
Details:
Minecraft Version: 1.9.1-pre3
Operating System: Mac OS X (x86_64) version 10.11.4
Java Version: 1.8.0_74, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 304587832 bytes (290 MB) / 625475584 bytes (596 MB) up to 932184064 bytes (889 MB)
JVM Flags: 2 total; -Xms512M -Xmx1000M
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
Profiler Position: N/A (disabled)
Player Count: 1 / 8; [lr['__null'/32, l='EEK! World corruptor bug test!', x=328.12, y=4.00, z=1160.03]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.I could not get the world to be "deleted" after running the command three times.
On the 2nd and 3rd time I did it, the Zombie remained after I loaded the world again.
Please link to this comment in the description
The following is based on decompiled version of Minecraft 1.9 using MCP 9.24 beta. All method and class names are the names used in the decompiled version.
The reason why this happens is because the leash knot breaks and the game tries to dismount the passengers based on the rotation of the leash knot. Because the methods net.minecraft.entity.EntityLeashKnot.readEntityFromNBT(NBTTagCompound) and net.minecraft.entity.EntityLeashKnot.updateFacingWithBoundingBox(EnumFacing) override the methods of its parent (net.minecraft.entity.EntityHanging class) and doing nothing when these methods are called, the Facing value is null.
Please attach the crash report.