Break redstone on top of trap doors early

This logic hooks into the neighbour update which should be invoked
as a result of redstone powering the trap door.

1 files changed, 40 insertions, 0 deletions

diff --git a/patches/server/0977-Break-redstone-on-top-of-trap-doors-early.patch b/patches/server/0977-Break-redstone-on-top-of-trap-doors-early.patch
new file mode 100644
index 0000000000..5142b3f57d
--- /dev/null
+++ b/patches/server/0977-Break-redstone-on-top-of-trap-doors-early.patch
@@ -0,0 +1,40 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Spottedleaf <[email protected]>
+Date: Mon, 1 May 2023 18:31:26 -0700
+Subject: [PATCH] Break redstone on top of trap doors early
+
+This logic hooks into the neighbour update which should be invoked
+as a result of redstone powering the trap door.
+
+diff --git a/src/main/java/net/minecraft/world/level/block/TrapDoorBlock.java b/src/main/java/net/minecraft/world/level/block/TrapDoorBlock.java
+index 89ae0fa000b5950f4c0d23b7e9f959989b9e9a84..29e43313ff6bd9b10cf6409e3519c0b2603b431e 100644
+--- a/src/main/java/net/minecraft/world/level/block/TrapDoorBlock.java
++++ b/src/main/java/net/minecraft/world/level/block/TrapDoorBlock.java
+@@ -125,7 +125,26 @@ public class TrapDoorBlock extends HorizontalDirectionalBlock implements SimpleW
+                     flag1 = eventRedstone.getNewCurrent() > 0;
+                 }
+                 // CraftBukkit end
+-                if ((Boolean) state.getValue(TrapDoorBlock.OPEN) != flag1) {
++                boolean open = (Boolean) state.getValue(TrapDoorBlock.OPEN) != flag1; // Paper - break redstone on trapdoors early
++                // Paper start - break redstone on trapdoors early
++                // note: this must run before any state for this block/its neighborus are written to the world
++                // we allow the redstone event to fire so that plugins can block
++                if (flag1 && open) { // if we are now powered and it caused the trap door to open
++                    // in this case, first check for the redstone on top first
++                    BlockPos abovePos = pos.above();
++                    BlockState above = world.getBlockState(abovePos);
++                    if (above.getBlock() instanceof RedStoneWireBlock) {
++                        world.setBlock(abovePos, Blocks.AIR.defaultBlockState(), Block.UPDATE_CLIENTS | Block.UPDATE_NEIGHBORS);
++                        Block.popResource(world, abovePos, new net.minecraft.world.item.ItemStack(net.minecraft.world.item.Items.REDSTONE));
++                        // now check that this didn't change our state
++                        if (world.getBlockState(pos) != state) {
++                            // our state was changed, so we cannot propagate this update
++                            return;
++                        }
++                    }
++                }
++                // Paper end - break redstone on trapdoors early
++                if (open) { // Paper - break redstone on trapdoors early
+                     state = (BlockState) state.setValue(TrapDoorBlock.OPEN, flag1);
+                     this.playSound((Player) null, world, pos, flag1);
+                 }