PaperMC / PaperMC/Paper

26.2 : Vanilla bug (MC-310372) causing redstone to randomly stop working when tripwire string is activated.

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upstream: vanilla version: 26.2
Dominant language
Java
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Description

Expected behavior

For stepping on a tripwire that is unconnected from any hooks to have no effect on redstone.

Observed/Actual behavior

On occasion when the tripwire is "triggered" / processes an entity colliding with it (be that a player, mob or item), something breaks in scheduled ticks causing redstone in the same chunk to stop working as expected. This affects not just complex redstone, but something as simple as a redstone repeater clock.

Steps/models to reproduce

Create the following structure, which is a redstone clock **crossing a chunk boundary

**, with a piece of string in one of the two chunks it occupies, and using a torch + redstone block to create the initial clock pulse.

Image

trigger the redstone clock to begin cycling.

step onto and off of the tripwire string (in the red area of the screenshot)
This may take up to a minute from testing for the bug to occur.

You can also use a dispenser to drop items through the tripwire string to trigger the bug.
A vanilla structure schematic of such a device has been added below.
tripwire_auto_bug.zip

The redstone clock freezes without any apparent external input.

Plugin and Datapack List
> version
[08:15:38 INFO]: This server is running Paper version 26.2-112-main@c9e894d (2026-08-11T05:18:39Z) (Implementing API version 26.2.build.112-stable)
You are running the latest version
Previous version: 26.2-94-3c6ac85 (MC: 26.2)
> plugins
[08:15:39 INFO]: ℹ Server Plugins (0):
> datapack list
[08:15:41 INFO]: There are 3 data pack(s) enabled: [vanilla (built-in)], [file/bukkit (world)], [paper (built-in)]
[08:15:41 INFO]: There are no more data packs available
>
Paper version
> version
[08:15:38 INFO]: This server is running Paper version 26.2-112-main@c9e894d (2026-08-11T05:18:39Z) (Implementing API version 26.2.build.112-stable)
You are running the latest version
Previous version: 26.2-94-3c6ac85 (MC: 26.2)
Other

Mojira ticket for the bug is here: https://bugs.mojang.com/browse/MC/issues/MC-310372 which contains an explanation of the underlying issue with the scheduled ticks that causes this.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the issue with the described cross-chunk redstone clock and tripwire setup, then read the linked Mojang MC-310372 explanation. Trace tripwire entity-collision processing and the scheduled-tick behavior it affects. Done means activating an unconnected tripwire no longer causes the redstone clock to freeze.

Written by the indexing model from the issue text.

Assessment

Tech stack
java
Domain
backend, game-dev
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
50/100

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