PaperMC/paper-server/patches/sources
Spottedleaf 47dd7e1c0a Fix piston physics inconsistency - MC-188840
Pistons invoke physics when they move blocks. The physics can cause
tnt blocks to ignite. However, pistons (when storing the blocks they "moved")
don't actually go back to the world state sometimes to check if something
like that happened. As a result they end up moving the tnt like it was
never ignited. This resulted in the ability to create machines
that can duplicate tnt, called "world eaters".
This patch makes the piston logic retrieve the block state from the world
prevent this from occuring.

This patch also sets the moved pos to air immediately after creating
the moving piston TE. This prevents the block from being updated from
other physics calls by the piston.

Tested against the following tnt duper design:
https://www.youtube.com/watch?v=mS7xxNGhjxs

This patch also affects every type of machine that utilises
this mechanic. For example, dead coral is removed by a physics
update when being moved while it is attached to slimeblocks.

Standard piston machines that don't destroy or modify the
blocks they move by physics updates should be entirely
unaffected.

This patch fixes https://bugs.mojang.com/browse/MC-188840

This patch also fixes rail duping and carpet duping.
2020-06-11 17:29:42 -07:00
..
com/mojang Reduce Either Optional allocation 2020-04-06 18:35:09 -07:00
net/minecraft Fix piston physics inconsistency - MC-188840 2020-06-11 17:29:42 -07:00