Paper/patches/unapplied/server/0278-BlockDestroyEvent.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 6 Feb 2019 00:20:33 -0500
Subject: [PATCH] BlockDestroyEvent

Adds an event for when the server is going to destroy a current block,
potentially causing it to drop. This event can be cancelled to avoid
the block destruction, such as preventing signs from popping when
floating in the air.

This can replace many uses of BlockPhysicsEvent

diff --git a/src/main/java/net/minecraft/world/level/Level.java b/src/main/java/net/minecraft/world/level/Level.java
index be2220eff094c735bdb0c3e777bfbcfa4d44a578..30ceb1e2765217e284abcb786b2c1f7b60f9c3dc 100644
--- a/src/main/java/net/minecraft/world/level/Level.java
+++ b/src/main/java/net/minecraft/world/level/Level.java
@@ -25,6 +25,7 @@ import net.minecraft.core.registries.Registries;
 import net.minecraft.network.protocol.Packet;
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
+import io.papermc.paper.util.MCUtil;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.level.FullChunkStatus;
 import net.minecraft.server.level.ServerLevel;
@@ -575,9 +576,26 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
             return false;
         } else {
             FluidState fluid = this.getFluidState(pos);
+            // Paper start - BlockDestroyEvent; while the above setAir method is named same and looks very similar
+            // they are NOT used with same intent and the above should not fire this event. The above method is more of a BlockSetToAirEvent,
+            // it doesn't imply destruction of a block that plays a sound effect / drops an item.
+            boolean playEffect = true;
+            BlockState effectType = iblockdata;
+            int xp = iblockdata.getBlock().getExpDrop(iblockdata, (ServerLevel) this, pos, ItemStack.EMPTY, true);
+            if (com.destroystokyo.paper.event.block.BlockDestroyEvent.getHandlerList().getRegisteredListeners().length > 0) {
+                com.destroystokyo.paper.event.block.BlockDestroyEvent event = new com.destroystokyo.paper.event.block.BlockDestroyEvent(org.bukkit.craftbukkit.block.CraftBlock.at(this, pos), fluid.createLegacyBlock().createCraftBlockData(), effectType.createCraftBlockData(), xp, drop);
+                if (!event.callEvent()) {
+                    return false;
+                }
+                effectType = ((CraftBlockData) event.getEffectBlock()).getState();
+                playEffect = event.playEffect();
+                drop = event.willDrop();
+                xp = event.getExpToDrop();
+            }
+            // Paper end - BlockDestroyEvent
 
-            if (!(iblockdata.getBlock() instanceof BaseFireBlock)) {
-                this.levelEvent(2001, pos, Block.getId(iblockdata));
+            if (playEffect && !(effectType.getBlock() instanceof BaseFireBlock)) { // Paper - BlockDestroyEvent
+                this.levelEvent(2001, pos, Block.getId(effectType)); // Paper - BlockDestroyEvent
             }
 
             if (drop) {