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MC-253549

Infinite structure block chain causes server to hang and game to time out/crash

Infinite structure block chain causes game to time out/crash

What I expected to happen was...:
The game would crash or the structure block chain would hit a limit

What actually happened was...:
Everything in the world freezes, entities stop moving, you can't open chests or place/interact with any block entities, but you can still place and break normal blocks and move around as normal

Steps to Reproduce:

[media]
  1. Recreate the design from the picture

  2. Using the /data modify command change the "powered" nbt tag of structure block next to the redstone block to 0b

  3. Put a name into the same structure block

  4. Use the other structure block to save the piston, carpet, redstone block, and structure block into the same name as the first structure block

  5. Go back to the first structure block and set it up to load 1 block in any horizontal direction and 0 blocks vertically

  6. Save this structure with the second structure block

  7. Now loading that structure will instantly cause the "crash", and the structures will never be placed, leaving a singleplayer world in this state seemed to cause it to save infinitely, and when used on a multiplayer server it timed every player out and then crashed the server

Linked issues

Attachments

Comments 5

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Could you attach the crash report from the server crash?

That's just watchdog shutting down the server if a tick takes over 30 seconds.

This can be fixed in 2 ways:

  1. Add a structure block load per tick limit (like the maxCommandChainLength game rule)

  2. Delay a structure block triggering the loading by 1 tick, allowing the server to still run while structure blocks get triggered.

When you try to close and save the world, the game hangs as well and you're forced to end the process using Task Manager. The game did log "Too many chained neighbor updates. Skipping the rest. First skipped position: ...", but only when I decided to close the world.

Essentially MC-108660.

yeet_3503

(Unassigned)

Confirmed

Platform

Normal

Crash, Structures

1.19, 1.19.1 Release Candidate 1, 23w32a

Retrieved