Sometimes the player falls under the map when changing instances

[MelonHell]

When I change the player's instance sometimes the player ends up in the void and falls down. The world begins to load only when the player moves to an adjacent chunk.

Also, I noticed that in ChunkLoader, the coordinates of the previous instance are passed, which means unnecessary chunks are loaded.

I noticed that this bug occurs more often when using AnvilLoader or another world loader. The flat world generator works very quickly and less frequently triggers this bug.

https://github.com/SkolkovoLab/Minestom/tree/instance-change-bug-demo

bandicam_2024-03-06_23-35-22-520.1.mp4

[Spliterash]

A small addition: I found out that this happens only when the player is near a previous chunk.
As I understand it, this happens because the server does not correctly calculate which chunks the player needs to unload
In other words, I managed to fix this problem by moving the lobby to 100000 coordinates, and as a result the lobby chunks were very far away from the minigame chunks.

[domrbeeson]

I'm experiencing this and can replicate it easily when simulating a slow CPU (docker container with --cpus=0.25) or with a ping above ~200ms. I'm also using my own chunk loader which pre loads all chunks, but it doesn't matter if I pre load or load on demand; it still happens with high frequency.