PaperMC/paper-server/nms-patches/net/minecraft/server/level/EntityTrackerEntry.patch

--- a/net/minecraft/server/level/EntityTrackerEntry.java
+++ b/net/minecraft/server/level/EntityTrackerEntry.java
@@ -42,6 +42,12 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
+// CraftBukkit start
+import net.minecraft.server.network.ServerPlayerConnection;
+import org.bukkit.entity.Player;
+import org.bukkit.event.player.PlayerVelocityEvent;
+// CraftBukkit end
+
 public class EntityTrackerEntry {
 
     private static final Logger LOGGER = LogManager.getLogger();
@@ -63,8 +69,12 @@
     private List<Entity> lastPassengers;
     private boolean wasRiding;
     private boolean wasOnGround;
+    // CraftBukkit start
+    private final Set<ServerPlayerConnection> trackedPlayers;
 
-    public EntityTrackerEntry(WorldServer worldserver, Entity entity, int i, boolean flag, Consumer<Packet<?>> consumer) {
+    public EntityTrackerEntry(WorldServer worldserver, Entity entity, int i, boolean flag, Consumer<Packet<?>> consumer, Set<ServerPlayerConnection> trackedPlayers) {
+        this.trackedPlayers = trackedPlayers;
+        // CraftBukkit end
         this.ap = Vec3D.ZERO;
         this.lastPassengers = Collections.emptyList();
         this.level = worldserver;
@@ -84,22 +94,22 @@
 
         if (!list.equals(this.lastPassengers)) {
             this.lastPassengers = list;
-            this.broadcast.accept(new PacketPlayOutMount(this.entity));
+            this.broadcastIncludingSelf(new PacketPlayOutMount(this.entity)); // CraftBukkit
         }
 
-        if (this.entity instanceof EntityItemFrame && this.tickCount % 10 == 0) {
+        if (this.entity instanceof EntityItemFrame /*&& this.tickCounter % 10 == 0*/) { // CraftBukkit - Moved below, should always enter this block
             EntityItemFrame entityitemframe = (EntityItemFrame) this.entity;
             ItemStack itemstack = entityitemframe.getItem();
 
-            if (itemstack.getItem() instanceof ItemWorldMap) {
+            if (this.tickCount % 10 == 0 && itemstack.getItem() instanceof ItemWorldMap) { // CraftBukkit - Moved this.tickCounter % 10 logic here so item frames do not enter the other blocks
                 Integer integer = ItemWorldMap.d(itemstack);
                 WorldMap worldmap = ItemWorldMap.a(integer, (World) this.level);
 
                 if (worldmap != null) {
-                    Iterator iterator = this.level.getPlayers().iterator();
+                    Iterator<ServerPlayerConnection> iterator = this.trackedPlayers.iterator(); // CraftBukkit
 
                     while (iterator.hasNext()) {
-                        EntityPlayer entityplayer = (EntityPlayer) iterator.next();
+                        EntityPlayer entityplayer = iterator.next().d(); // CraftBukkit
 
                         worldmap.a((EntityHuman) entityplayer, itemstack);
                         Packet<?> packet = worldmap.a(integer, entityplayer);
@@ -142,6 +152,17 @@
                 boolean flag2 = flag1 || this.tickCount % 60 == 0;
                 boolean flag3 = Math.abs(i - this.yRotp) >= 1 || Math.abs(j - this.xRotp) >= 1;
 
+                // CraftBukkit start - Code moved from below
+                if (flag2) {
+                    this.d();
+                }
+
+                if (flag3) {
+                    this.yRotp = i;
+                    this.xRotp = j;
+                }
+                // CraftBukkit end
+
                 if (this.tickCount > 0 || this.entity instanceof EntityArrow) {
                     long k = PacketPlayOutEntity.a(vec3d.x);
                     long l = PacketPlayOutEntity.a(vec3d.y);
@@ -180,6 +201,7 @@
                 }
 
                 this.c();
+                /* CraftBukkit start - Code moved up
                 if (flag2) {
                     this.d();
                 }
@@ -188,6 +210,7 @@
                     this.yRotp = i;
                     this.xRotp = j;
                 }
+                // CraftBukkit end */
 
                 this.wasRiding = false;
             }
@@ -203,7 +226,27 @@
 
         ++this.tickCount;
         if (this.entity.hurtMarked) {
-            this.broadcastIncludingSelf(new PacketPlayOutEntityVelocity(this.entity));
+            // CraftBukkit start - Create PlayerVelocity event
+            boolean cancelled = false;
+
+            if (this.entity instanceof EntityPlayer) {
+                Player player = (Player) this.entity.getBukkitEntity();
+                org.bukkit.util.Vector velocity = player.getVelocity();
+
+                PlayerVelocityEvent event = new PlayerVelocityEvent(player, velocity.clone());
+                this.entity.level.getCraftServer().getPluginManager().callEvent(event);
+
+                if (event.isCancelled()) {
+                    cancelled = true;
+                } else if (!velocity.equals(event.getVelocity())) {
+                    player.setVelocity(event.getVelocity());
+                }
+            }
+
+            if (!cancelled) {
+                this.broadcastIncludingSelf(new PacketPlayOutEntityVelocity(this.entity));
+            }
+            // CraftBukkit end
             this.entity.hurtMarked = false;
         }
 
@@ -218,13 +261,16 @@
         PlayerConnection playerconnection = entityplayer.connection;
 
         Objects.requireNonNull(entityplayer.connection);
-        this.a(playerconnection::sendPacket);
+        this.a(playerconnection::sendPacket, entityplayer); // CraftBukkit - add player
         this.entity.c(entityplayer);
     }
 
-    public void a(Consumer<Packet<?>> consumer) {
+    public void a(Consumer<Packet<?>> consumer, EntityPlayer entityplayer) { // CraftBukkit - add player
         if (this.entity.isRemoved()) {
-            EntityTrackerEntry.LOGGER.warn("Fetching packet for removed entity {}", this.entity);
+            // CraftBukkit start - Remove useless error spam, just return
+            // EntityTrackerEntry.LOGGER.warn("Fetching packet for removed entity {}", this.entity);
+            return;
+            // CraftBukkit end
         }
 
         Packet<?> packet = this.entity.getPacket();
@@ -240,6 +286,12 @@
         if (this.entity instanceof EntityLiving) {
             Collection<AttributeModifiable> collection = ((EntityLiving) this.entity).getAttributeMap().b();
 
+            // CraftBukkit start - If sending own attributes send scaled health instead of current maximum health
+            if (this.entity.getId() == entityplayer.getId()) {
+                ((EntityPlayer) this.entity).getBukkitEntity().injectScaledMaxHealth(collection, false);
+            }
+            // CraftBukkit end
+
             if (!collection.isEmpty()) {
                 consumer.accept(new PacketPlayOutUpdateAttributes(this.entity.getId(), collection));
             }
@@ -271,8 +323,14 @@
             if (!list.isEmpty()) {
                 consumer.accept(new PacketPlayOutEntityEquipment(this.entity.getId(), list));
             }
+            ((EntityLiving) this.entity).updateEquipment(); // CraftBukkit - SPIGOT-3789: sync again immediately after sending
         }
 
+        // CraftBukkit start - Fix for nonsensical head yaw
+        this.yHeadRotp = MathHelper.d(this.entity.getHeadRotation() * 256.0F / 360.0F);
+        consumer.accept(new PacketPlayOutEntityHeadRotation(this.entity, (byte) yHeadRotp));
+        // CraftBukkit end
+
         if (this.entity instanceof EntityLiving) {
             EntityLiving entityliving = (EntityLiving) this.entity;
             Iterator iterator = entityliving.getEffects().iterator();
@@ -313,6 +371,11 @@
             Set<AttributeModifiable> set = ((EntityLiving) this.entity).getAttributeMap().getAttributes();
 
             if (!set.isEmpty()) {
+                // CraftBukkit start - Send scaled max health
+                if (this.entity instanceof EntityPlayer) {
+                    ((EntityPlayer) this.entity).getBukkitEntity().injectScaledMaxHealth(set, false);
+                }
+                // CraftBukkit end
                 this.broadcastIncludingSelf(new PacketPlayOutUpdateAttributes(this.entity.getId(), set));
             }