Paper/patches/server/0829-Fix-ChunkSnapshot-isSectionEmpty-int.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jason Penilla <11360596+jpenilla@users.noreply.github.com>
Date: Thu, 9 Dec 2021 00:08:11 -0800
Subject: [PATCH] Fix ChunkSnapshot#isSectionEmpty(int)


diff --git a/src/main/java/org/bukkit/craftbukkit/CraftChunk.java b/src/main/java/org/bukkit/craftbukkit/CraftChunk.java
index db344e5b9f96f317a232304587e6b1673fc6067d..b4f7b91ac165e3171ffcf7d6a993af248d268959 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftChunk.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftChunk.java
@@ -286,8 +286,15 @@ public class CraftChunk implements Chunk {
         for (int i = 0; i < cs.length; i++) {
             CompoundTag data = new CompoundTag();
 
+            // Paper start
+            sectionEmpty[i] = cs[i].hasOnlyAir();
+            if (!sectionEmpty[i]) {
             data.put("block_states", ChunkSerializer.BLOCK_STATE_CODEC.encodeStart(NbtOps.INSTANCE, cs[i].getStates()).get().left().get());
             sectionBlockIDs[i] = ChunkSerializer.BLOCK_STATE_CODEC.parse(NbtOps.INSTANCE, data.getCompound("block_states")).get().left().get();
+            } else {
+                sectionBlockIDs[i] = CraftChunk.emptyBlockIDs;
+            }
+            // Paper end
 
             LevelLightEngine lightengine = chunk.level.getLightEngine();
             DataLayer skyLightArray = lightengine.getLayerListener(LightLayer.SKY).getDataLayerData(SectionPos.of(x, i, z));