From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 6 May 2020 05:00:57 -0400
Subject: [PATCH] Handle Oversized Tile Entities in chunks

Splits out Extra Packets if too many TE's are encountered to prevent
creating too large of a packet to sed.

Co authored by Spottedleaf

diff --git a/src/main/java/net/minecraft/server/PacketPlayOutMapChunk.java b/src/main/java/net/minecraft/server/PacketPlayOutMapChunk.java
index a0b87f89df77ba8ac6ce3f135d4f3a34ed2b3543..23223f3f45210cf23f44f9012f292db80df781a0 100644
--- a/src/main/java/net/minecraft/server/PacketPlayOutMapChunk.java
+++ b/src/main/java/net/minecraft/server/PacketPlayOutMapChunk.java
@@ -23,6 +23,15 @@ public class PacketPlayOutMapChunk implements Packet<PacketListenerPlayOut> {
 
     public PacketPlayOutMapChunk() {}
 
+    // Paper start
+    private final java.util.List<Packet> extraPackets = new java.util.ArrayList<>();
+    private static final int TE_LIMIT = Integer.getInteger("Paper.excessiveTELimit", 750);
+
+    @Override
+    public java.util.List<Packet> getExtraPackets() {
+        return extraPackets;
+    }
+    // Paper end
     public PacketPlayOutMapChunk(Chunk chunk, int i) {
         ChunkCoordIntPair chunkcoordintpair = chunk.getPos();
 
@@ -49,6 +58,7 @@ public class PacketPlayOutMapChunk implements Packet<PacketListenerPlayOut> {
         this.c = this.a(new PacketDataSerializer(this.j()), chunk, i);
         this.g = Lists.newArrayList();
         iterator = chunk.getTileEntities().entrySet().iterator();
+        int totalTileEntities = 0; // Paper
 
         while (iterator.hasNext()) {
             entry = (Entry) iterator.next();
@@ -57,6 +67,15 @@ public class PacketPlayOutMapChunk implements Packet<PacketListenerPlayOut> {
             int j = blockposition.getY() >> 4;
 
             if (this.f() || (i & 1 << j) != 0) {
+                // Paper start - improve oversized chunk data packet handling
+                if (++totalTileEntities > TE_LIMIT) {
+                    PacketPlayOutTileEntityData updatePacket = tileentity.getUpdatePacket();
+                    if (updatePacket != null) {
+                        this.extraPackets.add(updatePacket);
+                        continue;
+                    }
+                }
+                // Paper end
                 NBTTagCompound nbttagcompound = tileentity.b();
                 if (tileentity instanceof TileEntitySkull) { TileEntitySkull.sanitizeTileEntityUUID(nbttagcompound); } // Paper