I have been running
spreadplayers 0 0 2000 200000 true @a
to spread two players very far out on a fresh map (default world generation) as part of a mini-game. Most times it works, but about 1 time in 20 or 30, one of the players spawns underground, sometimes in a cave, or other times completely encased in blocks, suffocating.
I am unclear if this is related to a client-side latency issue (e.g. after spread-teleporting, you tend to 'fall through the world' until the fresh world generates in your location), or faulty logic in spreadplayers itself. Either way, it is no fun.
(As an aside, I did notice one time when I spawned underground in a cave, that digging directly up was a village on the surface, so possibly surface structures interact with this bug, or maybe that was just a coincidence.)
Linked issues
Comments 6
The lava and water is normal for spawning. Liquids have always counted as air for spawns. Try creating a custom flatland with the Waterworld preset. You'll always appear at the bottom of a 90 block deep ocean and if you're on survival it's not possible to get to the surface before drowning. Villages still spawn on the ocean floor, the insides of them containing air pockets and oblivious villagers.
Is this still an issue in the current Minecraft Snapshot 15w46a or later? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.
There have clearly been some fixes/changes here, so it's ok to mark this Resolved. I opened MC-92863 to track bugs in the new behavior, but that bug is much more minor.
It seems completely random, but I have spawned:
in a wall
underground in a cave
in a lava pool
on the floor of the ocean
'hit the ground to hard' at moment of spawn
etc, so it's just overall very buggy.