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MC-81656

Field determining whether or not a wither skull is blue is not saved to and read from NBT

The bug

Wither bosses can shoot blue wither skull if no enemy is around and there is enough space. The value if a wither skull is blue or not is not saved in the NBT data which means it loses this after reloading it, you cannot summon them in and you cannot test for them.

The reason

The following is based on a decompiled version of Minecraft 1.9 using MCP 9.24 beta.

The reason why this happens is because the field net.minecraft.entity.projectile.EntityWitherSkull.INVULNERABLE is not written to the NBT data and cannot be set based on the NBT data.

Note: A tag for this field should not be named "Invulnerable" as this value is only used for less destroyed blocks when it explodes and for rendering. The behaviour of the "Invulnerable" tag is not affected by this.

Linked issues

Comments

migrated

please submit one issue per ticket, there are actually 3 diffrent issues all relating to each other

marcono1234

Updated the report

migrated

Still an issue in 18w14b.

migrated

Confirmed for 1.13 pre 2

migrated

For reference: bedrock editions save it under a separate id: wither_skull_dangerous, so that’s likely a better fix (do note that saving it as dangerous_wither_skull, does make more sense).

ampolive

Can confirm in 1.17.1.

muzikbike

Likely relates to MC-172738

migrated

Same issue, yes, but the code to save field for these entities is not at all related, nor are the entities themselves related.

migrated

This is still an issue in 1.19.3. For context, this was reported 7 years ago.

clamlol

Affects 23w33a. Here are some repro steps:

How to reproduce:

  1. Get to a safe area in a creative world (eg. above the nether roof)

  2. /summon minecraft:armor_stand ~ ~ ~ {Invulnerable:1b,NoGravity:1b,Passengers:[{id:"minecraft:wither"}]}
  3. Wait for the wither to shoot its blue skulls

  4. Reload the world

Expected behavior: The skulls would remain blue.

Observed behavior: The skulls are now black, and some slight jittering due to MC-80142 can be observed if the skull flies far enough without hitting anything.

muzikbike

Relates to MC-172738 and MC-260236.

marcono1234

Nathan Adams

Confirmed

Low

Save Data

wither, wither_skull

Minecraft 1.8.7, Minecraft 1.9.2, Minecraft 16w38a, Minecraft 1.12.2, Minecraft 18w05a, ..., 1.18.1, 1.19.3, 23w17a, 1.20 Pre-release 1, 1.20.2

23w41a

Retrieved