Paper/Spigot-Server-Patches/0183-use-CB-BlockState-implementations-for-captured-block.patch

From acb4e329c24a42d0fa90ca0f05b0a24e885c97c5 Mon Sep 17 00:00:00 2001
From: Shane Freeder <theboyetronic@gmail.com>
Date: Thu, 16 Nov 2017 12:12:41 +0000
Subject: [PATCH] use CB BlockState implementations for captured blocks

When modifying the world, CB will store a copy of the affected
blocks in order to restore their state in the case that the event
is cancelled. This change only modifies the collection of blocks
in the world by normal means, e.g. not during tree population,
as the potentially marginal overheads would serve no advantage.

CB was using a CraftBlockState for all blocks, which causes issues
should any block that uses information beyond a data ID would suffer
from missing information, e.g. Skulls.

By using CBs CraftBlock#getState(), we will maintain a proper copy of
the blockstate that will be valid for restoration, as opposed to dropping
information on restoration when the event is cancelled.

diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
index a956dbc3d4..2f57c7bc76 100644
--- a/src/main/java/net/minecraft/server/World.java
+++ b/src/main/java/net/minecraft/server/World.java
@@ -66,7 +66,7 @@ public abstract class World implements GeneratorAccess, AutoCloseable {
 
     public boolean captureBlockStates = false;
     public boolean captureTreeGeneration = false;
-    public Map<BlockPosition, CapturedBlockState> capturedBlockStates = new HashMap<>();
+    public Map<BlockPosition, org.bukkit.craftbukkit.block.CraftBlockState> capturedBlockStates = new HashMap<>(); // Paper
     public Map<BlockPosition, TileEntity> capturedTileEntities = new HashMap<>();
     public List<EntityItem> captureDrops;
     public long ticksPerAnimalSpawns;
@@ -257,7 +257,7 @@ public abstract class World implements GeneratorAccess, AutoCloseable {
     public boolean setTypeAndData(BlockPosition blockposition, IBlockData iblockdata, int i) {
         // CraftBukkit start - tree generation
         if (this.captureTreeGeneration) {
-            CapturedBlockState blockstate = capturedBlockStates.get(blockposition);
+            CraftBlockState blockstate = capturedBlockStates.get(blockposition);
             if (blockstate == null) {
                 blockstate = CapturedBlockState.getTreeBlockState(this, blockposition, i);
                 this.capturedBlockStates.put(blockposition.immutableCopy(), blockstate);
@@ -277,7 +277,7 @@ public abstract class World implements GeneratorAccess, AutoCloseable {
             // CraftBukkit start - capture blockstates
             boolean captured = false;
             if (this.captureBlockStates && !this.capturedBlockStates.containsKey(blockposition)) {
-                CapturedBlockState blockstate = CapturedBlockState.getBlockState(this, blockposition, i);
+                CraftBlockState blockstate = (CraftBlockState) world.getBlockAt(blockposition.getX(), blockposition.getY(), blockposition.getZ()).getState(); // Paper - use CB getState to get a suitable snapshot
                 this.capturedBlockStates.put(blockposition.immutableCopy(), blockstate);
                 captured = true;
             }
@@ -545,7 +545,7 @@ public abstract class World implements GeneratorAccess, AutoCloseable {
     public IBlockData getType(BlockPosition blockposition) {
         // CraftBukkit start - tree generation
         if (captureTreeGeneration) {
-            CapturedBlockState previous = capturedBlockStates.get(blockposition);
+            CraftBlockState previous = capturedBlockStates.get(blockposition); // Paper
             if (previous != null) {
                 return previous.getHandle();
             }
-- 
2.25.1