Head rotation bug

[jd07159]

Spark link

https://spark.lucko.me/zDcvo7p2A3

Expected behavior

When the head rotates, the body should rotate as well.

Observed/Actual behavior

When the head rotates, the body should rotate as well, but it rotates after a few seconds.
I also tested it on Paper, and it worked properly. This bug is definitely an issue with Purpur.

Steps/models to reproduce

2024-12-19.01-31-22.mp4

Purpur version

Current Purpur Version: 1.21.3-2358-16ce24a (MC: 1.21.3)*

• You are running the latest version
  Previous: 1.21.3-81-da71382 (MC: 1.21.3)

Agreements

• I am running the latest version of Purpur available from https://purpurmc.org/downloads.
• I have searched for and ensured there isn't already an open issue regarding this.
• I ticked all the boxes without actually reading them
• My version of Minecraft is supported by Purpur.

Other

No response

[Onako2]

Try without any mods installed, afaik. rotations are handled on the client, no on the server

[jd07159]

Try without any mods installed, afaik. rotations are handled on the client, no on the server

When I tested it on paper under the same conditions, there was no problem. Is this really a mod issue?

2024-12-19.01-26-49.mp4

[granny]

Cannot give support for 1.21.3 since builds for 1.21.4 are out. Does this issue continue on 1.21.4 builds?

[jd07159]

The bug has been occurring since build 2354. It might be related to the pufferfish issue.
I haven't tested it on the latest version yet.

[granny]

Can confirm on the latest build of Purpur for 1.21.4. Removing Pufferfish patches fixes this bug. Will most likely drop pufferfish patches at some point tomorrow and wait for the Pufferfish devs to update to 1.21.4 before merging them back in. Once they do and you're able to reproduce this on Pufferfish 1.21.4 builds, report this bug to them.