Paper/patches/server/0880-Properly-resend-entities.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Owen1212055 <23108066+Owen1212055@users.noreply.github.com>
Date: Wed, 7 Dec 2022 17:25:19 -0500
Subject: [PATCH] Properly resend entities

This resolves some issues which caused entities to not be resent correctly.
Entities that are interacted with need to be resent to the client, so we resend all the entity
data to the player whilst making sure not to clear dirty entries from the tracker. This makes
sure that values will be correctly updated to other players.

This also adds utilities to aid in further preventing entity desyncs.

See: https://github.com/PaperMC/Paper/pull/1896

== AT ==
public net.minecraft.server.level.ChunkMap$TrackedEntity serverEntity

diff --git a/src/main/java/net/minecraft/network/syncher/SynchedEntityData.java b/src/main/java/net/minecraft/network/syncher/SynchedEntityData.java
index d088479d160dbd2fc90b48a30553be141db8eef2..ccb7d92b6c36b6225a2e640f8cea6c0da37464c8 100644
--- a/src/main/java/net/minecraft/network/syncher/SynchedEntityData.java
+++ b/src/main/java/net/minecraft/network/syncher/SynchedEntityData.java
@@ -253,14 +253,63 @@ public class SynchedEntityData {
     // CraftBukkit start
     public void refresh(ServerPlayer to) {
         if (!this.isEmpty()) {
-            List<SynchedEntityData.DataValue<?>> list = this.getNonDefaultValues();
+            List<SynchedEntityData.DataValue<?>> list = this.packAll(); // Paper - Update EVERYTHING not just not default
 
             if (list != null) {
+                if (to.getBukkitEntity().canSee(this.entity.getBukkitEntity())) { // Paper
                 to.connection.send(new ClientboundSetEntityDataPacket(this.entity.getId(), list));
+                } // Paper
             }
         }
     }
     // CraftBukkit end
+    // Paper start
+    // We need to pack all as we cannot rely on "non default values" or "dirty" ones.
+    // Because these values can possibly be desynced on the client.
+    @Nullable
+    private List<SynchedEntityData.DataValue<?>> packAll() {
+        if (this.isEmpty()) {
+            return null;
+        }
+
+        List<SynchedEntityData.DataValue<?>> list = new ArrayList<>();
+        for (DataItem<?> dataItem : this.itemsById.values()) {
+            list.add(dataItem.value());
+        }
+
+        return list;
+    }
+
+    // This method should only be used if the data of an entity could have became desynced
+    // due to interactions on the client.
+    public void resendPossiblyDesyncedEntity(ServerPlayer player) {
+        if (this.entity.tracker == null) {
+            return;
+        }
+
+        if (player.getBukkitEntity().canSee(entity.getBukkitEntity())) {
+            net.minecraft.server.level.ServerEntity serverEntity = this.entity.tracker.serverEntity;
+
+            List<net.minecraft.network.protocol.Packet<net.minecraft.network.protocol.game.ClientGamePacketListener>> list = new ArrayList<>();
+            serverEntity.sendPairingData(player, list::add);
+            player.connection.send(new net.minecraft.network.protocol.game.ClientboundBundlePacket(list));
+        }
+    }
+
+    // This method allows you to specifically resend certain data accessor keys to the client
+    public void resendPossiblyDesyncedDataValues(List<EntityDataAccessor<?>> keys, ServerPlayer to) {
+        if (!to.getBukkitEntity().canSee(this.entity.getBukkitEntity())) {
+            return;
+        }
+        List<SynchedEntityData.DataValue<?>> values = new ArrayList<>(keys.size());
+        for (EntityDataAccessor<?> key : keys) {
+            SynchedEntityData.DataItem<?> synchedValue = this.getItem(key);
+            values.add(synchedValue.value());
+        }
+
+        to.connection.send(new ClientboundSetEntityDataPacket(this.entity.getId(), values));
+    }
+    // Paper end
 
     public static class DataItem<T> {
 
diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
index a30523973711210e8c4b74d2f6cbce4314709338..d4187f23bdebbab0cbee72009e0257de3e1c876c 100644
--- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
@@ -2651,7 +2651,7 @@ public class ServerGamePacketListenerImpl extends ServerCommonPacketListenerImpl
 
                             // Entity in bucket - SPIGOT-4048 and SPIGOT-6859a
                             if ((entity instanceof Bucketable && entity instanceof LivingEntity && origItem != null && origItem.asItem() == Items.WATER_BUCKET) && (event.isCancelled() || ServerGamePacketListenerImpl.this.player.getInventory().getSelected() == null || ServerGamePacketListenerImpl.this.player.getInventory().getSelected().getItem() != origItem)) {
-                                ServerGamePacketListenerImpl.this.send(new ClientboundAddEntityPacket(entity));
+                                entity.getEntityData().resendPossiblyDesyncedEntity(player); // Paper - The entire mob gets deleted, so resend it.
                                 ServerGamePacketListenerImpl.this.player.containerMenu.sendAllDataToRemote();
                             }
 
diff --git a/src/main/java/net/minecraft/server/players/PlayerList.java b/src/main/java/net/minecraft/server/players/PlayerList.java
index 4bf3598f8d6f6f469a5a17e8067fd5035732da19..e1c0811c6dc8f3e268c60d23a25942a2c6d22475 100644
--- a/src/main/java/net/minecraft/server/players/PlayerList.java
+++ b/src/main/java/net/minecraft/server/players/PlayerList.java
@@ -376,7 +376,7 @@ public abstract class PlayerList {
         ((ServerLevel)player.level()).getChunkSource().chunkMap.addEntity(player); // Paper - track entity now
         // CraftBukkit end
 
-        player.getEntityData().refresh(player); // CraftBukkit - BungeeCord#2321, send complete data to self on spawn
+        //player.getEntityData().refresh(player); // CraftBukkit - BungeeCord#2321, send complete data to self on spawn Paper - THIS IS NOT NEEDED ANYMORE
 
         this.sendLevelInfo(player, worldserver1);
 
diff --git a/src/main/java/net/minecraft/world/entity/animal/Bucketable.java b/src/main/java/net/minecraft/world/entity/animal/Bucketable.java
index 37596c7b65f280be00e8e59ae18bd1aceae21080..eca18540aeb0b0d4098477d73b14c78a7bf9f455 100644
--- a/src/main/java/net/minecraft/world/entity/animal/Bucketable.java
+++ b/src/main/java/net/minecraft/world/entity/animal/Bucketable.java
@@ -109,8 +109,7 @@ public interface Bucketable {
             itemstack1 = CraftItemStack.asNMSCopy(playerBucketFishEvent.getEntityBucket());
             if (playerBucketFishEvent.isCancelled()) {
                 ((ServerPlayer) player).containerMenu.sendAllDataToRemote(); // We need to update inventory to resync client's bucket
-                ((ServerPlayer) player).connection.send(new ClientboundAddEntityPacket(entity)); // We need to play out these packets as the client assumes the fish is gone
-                entity.getEntityData().refresh((ServerPlayer) player); // Need to send data such as the display name to client
+                entity.getEntityData().resendPossiblyDesyncedEntity((ServerPlayer) player); // Paper
                 return Optional.of(InteractionResult.FAIL);
             }
             entity.playSound(((Bucketable) entity).getPickupSound(), 1.0F, 1.0F);
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
index 763462e4cf8abdd654b582150fab09f05e64f990..7cda23cf7400edcfa1436f6457edd7566cd42323 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
@@ -947,7 +947,11 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
             return;
         }
 
-        entityTracker.broadcast(this.getHandle().getAddEntityPacket());
+        // Paper start, resend possibly desynced entity instead of add entity packet
+        for (ServerPlayerConnection playerConnection : entityTracker.seenBy) {
+            this.getHandle().getEntityData().resendPossiblyDesyncedEntity(playerConnection.getPlayer());
+        }
+        // Paper end
     }
 
     private static PermissibleBase getPermissibleBase() {
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftItemFrame.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftItemFrame.java
index 0801bcdee8fcff0d388d302387e4f1d587e0a283..2fcd9b836d42e3549a3b6b921c57a4c103146dff 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftItemFrame.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftItemFrame.java
@@ -39,9 +39,11 @@ public class CraftItemFrame extends CraftHanging implements ItemFrame {
     protected void update() {
         super.update();
 
+        // Paper start, don't mark as dirty as this is handled in super.update()
         // mark dirty, so that the client gets updated with item and rotation
-        this.getHandle().getEntityData().markDirty(net.minecraft.world.entity.decoration.ItemFrame.DATA_ITEM);
-        this.getHandle().getEntityData().markDirty(net.minecraft.world.entity.decoration.ItemFrame.DATA_ROTATION);
+        //this.getHandle().getEntityData().markDirty(net.minecraft.world.entity.decoration.ItemFrame.DATA_ITEM);
+        //this.getHandle().getEntityData().markDirty(net.minecraft.world.entity.decoration.ItemFrame.DATA_ROTATION);
+        // Paper end
 
         // update redstone
         if (!this.getHandle().generation) {