From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Jake Potrebic Date: Wed, 22 Dec 2021 09:51:48 -0800 Subject: [PATCH] Fix sticky pistons and BlockPistonRetractEvent There is an explicit check in the handling code for empty pistons that prevents sticky pistons from firing the event. However when we look back at the history we see that this check was originally added so that ONLY sticky pistons would fire the retract event. I'm not sure why. https://hub.spigotmc.org/stash/projects/SPIGOT/repos/craftbukkit/commits/1092acbddf07edfa4100bc6824504ac75088e913 Over the course of several updates, the meaning of that field appears to have changed from "is NOT sticky" to "is sticky". So now its having the opposite effect. Only normal pistons fire the retraction event. And like all things in CB, it's just been carried around since. If we are to believe the history, the correct fix for this issue is to flip it so it only fires for sticky pistons, but that puts us in a bind. It's already firing for non-sticky pistons, changing it now would likely result in breakage. Furthermore, there is little documentation as to WHY that was ever intended to be the case. Instead we opt to remove the check entirely so that the event fires for all piston types. Co-authored-by: Zach Brown Co-authored-by: Madeline Miller diff --git a/src/main/java/net/minecraft/world/level/block/piston/PistonBaseBlock.java b/src/main/java/net/minecraft/world/level/block/piston/PistonBaseBlock.java index 6d3c9d6c75897af52bbcce50bf23f28269a3ff5c..4d4d28377e5766432d3fd18192bbc1d795fbd69c 100644 --- a/src/main/java/net/minecraft/world/level/block/piston/PistonBaseBlock.java +++ b/src/main/java/net/minecraft/world/level/block/piston/PistonBaseBlock.java @@ -146,15 +146,15 @@ public class PistonBaseBlock extends DirectionalBlock { } // CraftBukkit start - if (!this.isSticky) { - org.bukkit.block.Block block = world.getWorld().getBlockAt(pos.getX(), pos.getY(), pos.getZ()); - BlockPistonRetractEvent event = new BlockPistonRetractEvent(block, ImmutableList.of(), CraftBlock.notchToBlockFace(enumdirection)); - world.getCraftServer().getPluginManager().callEvent(event); - - if (event.isCancelled()) { - return; - } - } + // if (!this.isSticky) { // Paper - Move further down + // org.bukkit.block.Block block = world.getWorld().getBlockAt(pos.getX(), pos.getY(), pos.getZ()); + // BlockPistonRetractEvent event = new BlockPistonRetractEvent(block, ImmutableList.of(), CraftBlock.notchToBlockFace(enumdirection)); + // world.getCraftServer().getPluginManager().callEvent(event); + // + // if (event.isCancelled()) { + // return; + // } + // } // PAIL: checkME - what happened to setTypeAndData? // CraftBukkit end world.blockEvent(pos, this, b0, enumdirection.get3DDataValue()); @@ -236,6 +236,13 @@ public class PistonBaseBlock extends DirectionalBlock { BlockState iblockdata1 = (BlockState) ((BlockState) Blocks.MOVING_PISTON.defaultBlockState().setValue(MovingPistonBlock.FACING, enumdirection)).setValue(MovingPistonBlock.TYPE, this.isSticky ? PistonType.STICKY : PistonType.DEFAULT); + // Paper start - Move empty piston retract call to fix multiple event fires + if (!this.isSticky) { + if (!new BlockPistonRetractEvent(CraftBlock.at(world, pos), java.util.Collections.emptyList(), CraftBlock.notchToBlockFace(enumdirection)).callEvent()) { + return false; + } + } + // Paper end world.setBlock(pos, iblockdata1, 20); world.setBlockEntity(MovingPistonBlock.newMovingBlockEntity(pos, iblockdata1, (BlockState) this.defaultBlockState().setValue(PistonBaseBlock.FACING, Direction.from3DDataValue(data & 7)), enumdirection, false, true)); // Paper - diff on change world.blockUpdated(pos, iblockdata1.getBlock()); @@ -262,6 +269,13 @@ public class PistonBaseBlock extends DirectionalBlock { if (type == 1 && !iblockdata2.isAir() && PistonBaseBlock.isPushable(iblockdata2, world, blockposition1, enumdirection.getOpposite(), false, enumdirection) && (iblockdata2.getPistonPushReaction() == PushReaction.NORMAL || iblockdata2.is(Blocks.PISTON) || iblockdata2.is(Blocks.STICKY_PISTON))) { this.moveBlocks(world, pos, enumdirection, false); } else { + // Paper start - fire BlockPistonRetractEvent for sticky pistons retracting nothing (air) + if (type == TRIGGER_CONTRACT && iblockdata2.isAir()) { + if (!new BlockPistonRetractEvent(CraftBlock.at(world, pos), java.util.Collections.emptyList(), CraftBlock.notchToBlockFace(enumdirection)).callEvent()) { + return false; + } + } + // Paper end world.removeBlock(pos.relative(enumdirection), false); } }