PaperMC/paper-server/patches/sources/net/minecraft/world/entity/NeutralMob.java.patch

--- a/net/minecraft/world/entity/NeutralMob.java
+++ b/net/minecraft/world/entity/NeutralMob.java
@@ -8,6 +8,9 @@
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.level.GameRules;
 import net.minecraft.world.level.Level;
+// CraftBukkit start
+import org.bukkit.event.entity.EntityTargetEvent;
+// CraftBukkit end
 
 public interface NeutralMob {
 
@@ -48,14 +51,14 @@
                     if (entity instanceof Mob) {
                         Mob entityinsentient = (Mob) entity;
 
-                        this.setTarget(entityinsentient);
+                        this.setTarget(entityinsentient, EntityTargetEvent.TargetReason.UNKNOWN, false); // CraftBukkit
                         this.setLastHurtByMob(entityinsentient);
                     }
 
                     if (entity instanceof Player) {
                         Player entityhuman = (Player) entity;
 
-                        this.setTarget(entityhuman);
+                        this.setTarget(entityhuman, EntityTargetEvent.TargetReason.UNKNOWN, false); // CraftBukkit
                         this.setLastHurtByPlayer(entityhuman);
                     }
 
@@ -114,7 +117,7 @@
     default void stopBeingAngry() {
         this.setLastHurtByMob((LivingEntity) null);
         this.setPersistentAngerTarget((UUID) null);
-        this.setTarget((LivingEntity) null);
+        this.setTarget((LivingEntity) null, org.bukkit.event.entity.EntityTargetEvent.TargetReason.FORGOT_TARGET, true); // CraftBukkit
         this.setRemainingPersistentAngerTime(0);
     }
 
@@ -127,6 +130,8 @@
 
     void setTarget(@Nullable LivingEntity target);
 
+    boolean setTarget(@Nullable LivingEntity entityliving, org.bukkit.event.entity.EntityTargetEvent.TargetReason reason, boolean fireEvent); // CraftBukkit
+
     boolean canAttack(LivingEntity target);
 
     @Nullable