Paper/paper-server/patches/sources/net/minecraft/server/level/ServerEntity.java.patch

--- a/net/minecraft/server/level/ServerEntity.java
+++ b/net/minecraft/server/level/ServerEntity.java
@@ -31,7 +31,6 @@
 import net.minecraft.network.protocol.game.ClientboundUpdateAttributesPacket;
 import net.minecraft.network.protocol.game.VecDeltaCodec;
 import net.minecraft.network.syncher.SynchedEntityData;
-import net.minecraft.util.Mth;
 import net.minecraft.world.entity.Entity;
 import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.entity.Leashable;
@@ -50,6 +49,13 @@
 import net.minecraft.world.phys.Vec3;
 import org.slf4j.Logger;
 
+// CraftBukkit start
+import net.minecraft.server.network.ServerPlayerConnection;
+import net.minecraft.util.Mth;
+import org.bukkit.entity.Player;
+import org.bukkit.event.player.PlayerVelocityEvent;
+// CraftBukkit end
+
 public class ServerEntity {
 
     private static final Logger LOGGER = LogUtils.getLogger();
@@ -69,18 +75,22 @@
     private Vec3 lastSentMovement;
     private int tickCount;
     private int teleportDelay;
-    private List<Entity> lastPassengers = Collections.emptyList();
+    private List<Entity> lastPassengers = com.google.common.collect.ImmutableList.of(); // Paper - optimize passenger checks
     private boolean wasRiding;
     private boolean wasOnGround;
     @Nullable
     private List<SynchedEntityData.DataValue<?>> trackedDataValues;
+    // CraftBukkit start
+    private final Set<ServerPlayerConnection> trackedPlayers;
 
-    public ServerEntity(ServerLevel world, Entity entity, int tickInterval, boolean alwaysUpdateVelocity, Consumer<Packet<?>> receiver) {
-        this.level = world;
-        this.broadcast = receiver;
+    public ServerEntity(ServerLevel worldserver, Entity entity, int i, boolean flag, Consumer<Packet<?>> consumer, Set<ServerPlayerConnection> trackedPlayers) {
+        this.trackedPlayers = trackedPlayers;
+        // CraftBukkit end
+        this.level = worldserver;
+        this.broadcast = consumer;
         this.entity = entity;
-        this.updateInterval = tickInterval;
-        this.trackDelta = alwaysUpdateVelocity;
+        this.updateInterval = i;
+        this.trackDelta = flag;
         this.positionCodec.setBase(entity.trackingPosition());
         this.lastSentMovement = entity.getDeltaMovement();
         this.lastSentYRot = Mth.packDegrees(entity.getYRot());
@@ -94,7 +104,7 @@
         List<Entity> list = this.entity.getPassengers();
 
         if (!list.equals(this.lastPassengers)) {
-            this.broadcast.accept(new ClientboundSetPassengersPacket(this.entity));
+            this.broadcastAndSend(new ClientboundSetPassengersPacket(this.entity)); // CraftBukkit
             ServerEntity.removedPassengers(list, this.lastPassengers).forEach((entity) -> {
                 if (entity instanceof ServerPlayer entityplayer) {
                     entityplayer.connection.teleport(entityplayer.getX(), entityplayer.getY(), entityplayer.getZ(), entityplayer.getYRot(), entityplayer.getXRot());
@@ -106,19 +116,19 @@
 
         Entity entity = this.entity;
 
-        if (entity instanceof ItemFrame entityitemframe) {
-            if (this.tickCount % 10 == 0) {
+        if (!this.trackedPlayers.isEmpty() && entity instanceof ItemFrame entityitemframe) { // Paper - Perf: Only tick item frames if players can see it
+            if (true || this.tickCount % 10 == 0) { // CraftBukkit - Moved below, should always enter this block
                 ItemStack itemstack = entityitemframe.getItem();
 
-                if (itemstack.getItem() instanceof MapItem) {
+                if (this.level.paperConfig().maps.itemFrameCursorUpdateInterval > 0 && this.tickCount % this.level.paperConfig().maps.itemFrameCursorUpdateInterval == 0 && itemstack.getItem() instanceof MapItem) { // CraftBukkit - Moved this.tickCounter % 10 logic here so item frames do not enter the other blocks // Paper - Make item frame map cursor update interval configurable
                     MapId mapid = (MapId) itemstack.get(DataComponents.MAP_ID);
                     MapItemSavedData worldmap = MapItem.getSavedData(mapid, this.level);
 
                     if (worldmap != null) {
-                        Iterator iterator = this.level.players().iterator();
+                        Iterator<ServerPlayerConnection> iterator = this.trackedPlayers.iterator(); // CraftBukkit
 
                         while (iterator.hasNext()) {
-                            ServerPlayer entityplayer = (ServerPlayer) iterator.next();
+                            ServerPlayer entityplayer = iterator.next().getPlayer(); // CraftBukkit
 
                             worldmap.tickCarriedBy(entityplayer, itemstack);
                             Packet<?> packet = worldmap.getUpdatePacket(mapid, entityplayer);
@@ -248,6 +258,27 @@
 
         ++this.tickCount;
         if (this.entity.hurtMarked) {
+            // CraftBukkit start - Create PlayerVelocity event
+            boolean cancelled = false;
+
+            if (this.entity instanceof ServerPlayer) {
+                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) {
+                return;
+            }
+            // CraftBukkit end
             this.entity.hurtMarked = false;
             this.broadcastAndSend(new ClientboundSetEntityMotionPacket(this.entity));
         }
@@ -298,7 +329,10 @@
 
     public void sendPairingData(ServerPlayer player, Consumer<Packet<ClientGamePacketListener>> sender) {
         if (this.entity.isRemoved()) {
-            ServerEntity.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<ClientGamePacketListener> packet = this.entity.getAddEntityPacket(this);
@@ -313,6 +347,12 @@
         if (this.entity instanceof LivingEntity) {
             Collection<AttributeInstance> collection = ((LivingEntity) this.entity).getAttributes().getSyncableAttributes();
 
+            // CraftBukkit start - If sending own attributes send scaled health instead of current maximum health
+            if (this.entity.getId() == player.getId()) {
+                ((ServerPlayer) this.entity).getBukkitEntity().injectScaledMaxHealth(collection, false);
+            }
+            // CraftBukkit end
+
             if (!collection.isEmpty()) {
                 sender.accept(new ClientboundUpdateAttributesPacket(this.entity.getId(), collection));
             }
@@ -344,6 +384,7 @@
             if (!list.isEmpty()) {
                 sender.accept(new ClientboundSetEquipmentPacket(this.entity.getId(), list));
             }
+            ((LivingEntity) this.entity).detectEquipmentUpdatesPublic(); // CraftBukkit - SPIGOT-3789: sync again immediately after sending
         }
 
         if (!this.entity.getPassengers().isEmpty()) {
@@ -396,6 +437,11 @@
             Set<AttributeInstance> set = ((LivingEntity) this.entity).getAttributes().getAttributesToSync();
 
             if (!set.isEmpty()) {
+                // CraftBukkit start - Send scaled max health
+                if (this.entity instanceof ServerPlayer) {
+                    ((ServerPlayer) this.entity).getBukkitEntity().injectScaledMaxHealth(set, false);
+                }
+                // CraftBukkit end
                 this.broadcastAndSend(new ClientboundUpdateAttributesPacket(this.entity.getId(), set));
             }