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MC-157644

Extended block updates do not propagate outwards

The bug

Redstone components can be powered from a redstone wire that is no longer powered.

To reproduce

  1. Place a block of TNT on the ground

  2. Place redstone dust on the ground directly in front of the TNT block

  3. Place a redstone torch next to the redstone dust, in such a way that it is diagonal to the TNT block

  4. Break the torch
    → ❌ The TNT ignites for some reason

Video

[media]

Linked issues

Attachments

Comments 13

Can confirm in 20w51a.

This is a little something we redstone engineers call quasi-connectivity.

Yes, I am aware due to now being quite the technical player. Is there a way to close this (as while its technically a bug despite mojang stating they are not removing it)?

Can confirm in 21w06a.

Can confirm in 1.16.5 and 21w08b.

3 more comments

This might be MC-9714?

Yup, that's the same bug.

This bug is absolutely not MC-9714
MC-196649 is a duplicate of this bug tho.
This is actually just normal Redstone behavior. The bug is actually caused by the Redstone torch updating the TNT before updating the Redstone dust. When the TNT gets updated it notices that the Redstone dust is still powered and lights itself.

With a Redstone block however, the Redstone block does not update that far and the TNT is never updated.

A fix can be found here: https://github.com/fxmorin/carpet-fixes/blob/1.18/src/main/java/carpetfixes/mixins/blockUpdates/RedstoneTorchBlock_updateOrderOnBreakMixin.java
Although the proper fix would be to write the torch updates to be done in the correct order, without all the duplicate updates.

I suggest renaming this bug report to: `Extended Block Updates do not propagate outwards`
Since this only effect blocks that give extended block updates. It also affects all Redstone components, not just TNT

Is this issue still reproducible in 24w33a? Speaking from a visual standpoint, the redstone wire is visually lit and directed towards the TNT:

[media]

The currently result would appear to be expected.

Tyler

(Unassigned)

Confirmed

Redstone

1.14.4, 1.15 Pre-Release 2, 1.16.1, 1.16.2 Pre-release 1, 1.16.2 Pre-release 2, ..., 21w06a, 21w08b, 21w15a, 1.17.1 Release Candidate 1, 1.17.1

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