The bug
If a world using custom generation has Mansion generation enabled but has noise settings such that no terrain generates anywhere, then leveling up a cartographer to Journeyman or typing the command /locate mansion
causes a tick freeze that prevents debug crashes from working. The same applies with /locate nether_fossil
in the Nether, and /locate endcity
in the End.
How to reproduce
Open the attached world, or generate a world using the Import Settings button and the attached generation preset. (The attached world has a normal Nether and End.) The game mode must be Creative or Spectator to prevent an infinite death loop.
Execute the command
/locate mansion
, or level up a cartographer villager to Journeyman
→ ❌ Entities and some other processes stop working, and trying to force a debug crash never finishes, similarly to the effects of MC-175269.
Note 1: In the attached world, teleporting to the coordinates where the same seed produces a known Woodland Mansion reveals there is no mansion in sight.
Note 2: I have tested all other structures to see which ones cause the issue.
Nether Fossils and End Cities do not generate and cause the same issue as Mansions when using /locate.
Buried Treasure does not generate a chest. Depending on the exact world generator settings used,
/locate buried_treasure
will either output "Could not find the structure nearby", or will point to where a buried treasure chest would be generated normally. In the former case, any treasure maps generated from Shipwreck or Ocean Ruin loot will be replaced by empty maps.Mineshafts and Strongholds do not generate, and
/locate mineshaft
outputs "Could not find the structure nearby". Eyes of Ender do nothing.Ocean monuments still generate, surrounded by a cuboid of water. Ocean explorer maps are not broken.
Ruined Portals generate in the Nether but not in the Overworld;
/locate ruined_portal
finds a location in both dimensions, but nothing is generated at said location in the Overworld.Bastion Remnants float, with the bottom near y:31.
All other structures generate on top of the void and are findable via /locate as normal. Underground parts of certain structures, such as igloo basements, do not generate. In 20w46a, the bottom two blocks of buildings are missing; the lowest generated block is at y:1.
Linked issues
relates to 2
Attachments
Comments

Can this still be reproduced in 1.18-pre3?

I'm assuming I would need a new datapack for 1.18 versions (haven't tested the existing one).
But I'm in uni and don't have the time to learn about the new changes to worldgen and datapacks at the moment.
I guess reassign this ticket to someone else with a lot of datapack and/or worldgen knowledge?

Can confirm in 1.19.3 and 23w03a

Are you still experiencing this issue in the newest version?
If so, could you provide more detailed repro steps?
I am unable to reproduce this issue in 1.17.