Attempting to ride a player cross-world causes weirdness

[RoyCurtis]

Reproduction

1. Have player A go to overworld
2. Have player B go to the end
3. Execute /ride PlayerA PlayerB

Expected

PlayerA is teleported to PlayerB's world and is then attached to them

Actual

• PlayerA sees chunks disappear and may start falling
• When PlayerA dismounts, they teleport to PlayerB's coordinates but in PlayerA's world
• PlayerA will begin seeing PlayerB and all entities around them, as if they are in PlayerA's world

Workarounds

• Make rider teleport to ridee first
• Fix bug in Craftbukkit

Notes

I believe this is a bug with vanilla, where attaching an entity to another entity doesn't take differing worlds to account

[RoyCurtis]

Fixed by teleporting player prior to ride