[1.19.x] Make LivingSetAttackTargetEvent compatible with the Brain/Behavior system. (Port of PR #8918) (#8954)

patches/minecraft/net/minecraft/world/entity/Mob.java.patch

@@ -1,10 +1,15 @@
 --- a/net/minecraft/world/entity/Mob.java
 +++ b/net/minecraft/world/entity/Mob.java
-@@ -211,6 +_,7 @@
+@@ -210,7 +_,11 @@
+    }
  
     public void m_6710_(@Nullable LivingEntity p_21544_) {
-       this.f_21362_ = p_21544_;
-+      net.minecraftforge.common.ForgeHooks.onLivingSetAttackTarget(this, p_21544_);
+-      this.f_21362_ = p_21544_;
++      net.minecraftforge.event.entity.living.LivingChangeTargetEvent changeTargetEvent = net.minecraftforge.common.ForgeHooks.onLivingChangeTarget(this, p_21544_, net.minecraftforge.event.entity.living.LivingChangeTargetEvent.LivingTargetType.MOB_TARGET);
++      if(!changeTargetEvent.isCanceled()) {
++          this.f_21362_ = changeTargetEvent.getNewTarget();
++          net.minecraftforge.common.ForgeHooks.onLivingSetAttackTarget(this, this.f_21362_); // TODO: Remove in 1.20
++      }
     }
  
     public boolean m_6549_(EntityType<?> p_21399_) {

patches/minecraft/net/minecraft/world/entity/ai/behavior/StartAttacking.java.patch

@@ -0,0 +1,16 @@
+--- a/net/minecraft/world/entity/ai/behavior/StartAttacking.java
++++ b/net/minecraft/world/entity/ai/behavior/StartAttacking.java
+@@ -46,7 +_,11 @@
+    }
+ 
+    public static <E extends Mob> void m_24213_(E p_24214_, LivingEntity p_24215_) {
+-      p_24214_.m_6274_().m_21879_(MemoryModuleType.f_26372_, p_24215_);
+-      p_24214_.m_6274_().m_21936_(MemoryModuleType.f_26326_);
++      net.minecraftforge.event.entity.living.LivingChangeTargetEvent changeTargetEvent = net.minecraftforge.common.ForgeHooks.onLivingChangeTarget(p_24214_, p_24215_, net.minecraftforge.event.entity.living.LivingChangeTargetEvent.LivingTargetType.BEHAVIOR_TARGET);
++      if(!changeTargetEvent.isCanceled()) {
++          p_24214_.m_6274_().m_21879_(MemoryModuleType.f_26372_, changeTargetEvent.getNewTarget());
++          p_24214_.m_6274_().m_21936_(MemoryModuleType.f_26326_);
++          net.minecraftforge.common.ForgeHooks.onLivingSetAttackTarget(p_24214_, changeTargetEvent.getNewTarget(), net.minecraftforge.event.entity.living.LivingChangeTargetEvent.LivingTargetType.BEHAVIOR_TARGET); // TODO: Remove in 1.20
++      }
+    }
+ }

src/main/java/net/minecraftforge/common/ForgeHooks.java

@@ -118,12 +118,14 @@ import net.minecraftforge.event.entity.EntityTravelToDimensionEvent;
 import net.minecraftforge.event.entity.item.ItemTossEvent;
 import net.minecraftforge.event.entity.living.EnderManAngerEvent;
 import net.minecraftforge.event.entity.living.LivingAttackEvent;
+import net.minecraftforge.event.entity.living.LivingChangeTargetEvent;
 import net.minecraftforge.event.entity.living.LivingDamageEvent;
 import net.minecraftforge.event.entity.living.LivingDeathEvent;
 import net.minecraftforge.event.entity.living.LivingDropsEvent;
 import net.minecraftforge.event.entity.living.LivingEvent;
 import net.minecraftforge.event.entity.living.LivingEvent.LivingJumpEvent;
 import net.minecraftforge.event.entity.living.LivingEvent.LivingTickEvent;
+import net.minecraftforge.event.entity.living.LivingChangeTargetEvent.ILivingTargetType;
 import net.minecraftforge.event.entity.living.LivingFallEvent;
 import net.minecraftforge.event.entity.living.LivingHurtEvent;
 import net.minecraftforge.event.entity.living.LivingKnockBackEvent;
@@ -263,11 +265,28 @@ public class ForgeHooks
     //Optifine Helper Functions u.u, these are here specifically for Optifine
     //Note: When using Optifine, these methods are invoked using reflection, which
     //incurs a major performance penalty.
+    // TODO: Remove in 1.20
+    @Deprecated(since = "1.19.2", forRemoval = true)
     public static void onLivingSetAttackTarget(LivingEntity entity, LivingEntity target)
     {
         MinecraftForge.EVENT_BUS.post(new LivingSetAttackTargetEvent(entity, target));
     }
 
+    // TODO: Remove in 1.20
+    @Deprecated(since = "1.19.2", forRemoval = true)
+    public static void onLivingSetAttackTarget(LivingEntity entity, LivingEntity target, ILivingTargetType targetType)
+    {
+        MinecraftForge.EVENT_BUS.post(new LivingSetAttackTargetEvent(entity, target, targetType));
+    }
+    
+    public static LivingChangeTargetEvent onLivingChangeTarget(LivingEntity entity, LivingEntity originalTarget, ILivingTargetType targetType)
+    {
+        LivingChangeTargetEvent event = new LivingChangeTargetEvent(entity, originalTarget, targetType);
+        MinecraftForge.EVENT_BUS.post(event);
+        
+        return event;
+    }
+
     public static boolean onLivingTick(LivingEntity entity)
     {
         return MinecraftForge.EVENT_BUS.post(new LivingTickEvent(entity));

src/main/java/net/minecraftforge/event/entity/living/LivingChangeTargetEvent.java

@@ -0,0 +1,104 @@
+package net.minecraftforge.event.entity.living;
+
+import net.minecraft.world.entity.LivingEntity;
+import net.minecraft.world.entity.Mob;
+import net.minecraft.world.entity.ai.behavior.StartAttacking;
+import net.minecraftforge.common.ForgeHooks;
+import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.eventbus.api.Cancelable;
+
+/**
+ * This event allows you to change the target an entity has. <br>
+ * This event is fired before {@link LivingSetAttackTargetEvent}. <br>
+ * <br>
+ * This event is fired via the {@link ForgeHooks#onLivingChangeTarget(LivingEntity, LivingEntity, ILivingTargetType)}<br>
+ * <br>
+ * {@link #getOriginalTarget()} returns the target that should originally be set.
+ * The return value cannot be affected by calling {@link #setNewTarget(LivingEntity)}.<br>
+ * {@link #getNewTarget()} returns the new target that this entity will have.
+ * The return value can be affected by calling {@link #setNewTarget(LivingEntity)}.<br>
+ * {@link #getTargetType()} returns the target type that caused the change of targets.<br>
+ * <br>
+ * This event is {@link net.minecraftforge.eventbus.api.Cancelable}.<br>
+ * <br>
+ * If you cancel this event, the target will not be changed and it will stay the same.
+ * Cancelling this event will prevent {@link LivingSetAttackTargetEvent} from being posted.<br>
+ * <br>
+ * This event does not have a result. {@link HasResult}<br>
+ * <br>
+ * This event is fired on the {@link MinecraftForge#EVENT_BUS}.
+ */
+@Cancelable
+public class LivingChangeTargetEvent extends LivingEvent
+{
+    private final ILivingTargetType targetType;
+    private final LivingEntity originalTarget;
+    private LivingEntity newTarget;
+    
+    public LivingChangeTargetEvent(LivingEntity entity, LivingEntity originalTarget, ILivingTargetType targetType)
+    {
+        super(entity);
+        this.originalTarget = originalTarget;
+        this.newTarget = originalTarget;
+        this.targetType = targetType;
+    }
+
+    /**
+     * {@return the new target of this entity.}
+     */
+    public LivingEntity getNewTarget()
+    {
+        return newTarget;
+    }
+
+    /**
+     * Sets the new target this entity shall have.
+     * @param newTarget The new target of this entity.
+     */
+    public void setNewTarget(LivingEntity newTarget)
+    {
+        this.newTarget = newTarget;
+    }
+    
+    /**
+     * {@return the living target type.}
+     */
+    public ILivingTargetType getTargetType()
+    {
+        return targetType;
+    }
+
+    /**
+     * {@return the original entity MC intended to use as a target before firing this event.}
+     */
+    public LivingEntity getOriginalTarget()
+    {
+        return originalTarget;
+    }
+    
+    
+    /**
+     * A living target type indicates what kind of system caused a change of
+     * targets. For a list of default target types, take a look at
+     * {@link LivingTargetType}.
+     */
+    public static interface ILivingTargetType
+    {
+        
+    }
+    
+    /**
+     * This enum contains two default living target types.
+     */
+    public static enum LivingTargetType implements ILivingTargetType
+    {
+        /**
+         * This target type indicates that the target has been set by calling {@link Mob#setTarget(LivingEntity)}.
+         */
+        MOB_TARGET,
+        /**
+         * This target type indicates that the target has been set by the {@link StartAttacking} behavior.
+         */
+        BEHAVIOR_TARGET;
+    }
+}

src/main/java/net/minecraftforge/event/entity/living/LivingSetAttackTargetEvent.java

@@ -7,17 +7,23 @@ package net.minecraftforge.event.entity.living;
 
 import net.minecraft.world.entity.LivingEntity;
 import net.minecraft.world.entity.Mob;
+import net.minecraft.world.entity.ai.behavior.StartAttacking;
 import net.minecraftforge.common.ForgeHooks;
 import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.event.entity.living.LivingChangeTargetEvent.ILivingTargetType;
+import net.minecraftforge.event.entity.living.LivingChangeTargetEvent.LivingTargetType;
 
 /**
+ * This event is deprecated. Use {@link LivingChangeTargetEvent} instead.<br>
+ * <br>
  * LivingSetAttackTargetEvent is fired when an Entity sets a target to attack.<br>
  * This event is fired whenever an Entity sets a target to attack in
- * {@link Mob#setTarget(LivingEntity)}.<br>
+ * {@link Mob#setTarget(LivingEntity)} or {@link StartAttacking#setAttackTarget(Mob, LivingEntity)}<br>
  * <br>
  * This event is fired via the {@link ForgeHooks#onLivingSetAttackTarget(LivingEntity, LivingEntity)}.<br>
  * <br>
- * {@link #target} contains the newly targeted Entity.<br>
+ * {@link #getTarget} returns the newly targeted Entity.<br>
+ * {@link #getTargetType()} returns the target type that caused the change of targets.<br>
  * <br>
  * This event is not {@link net.minecraftforge.eventbus.api.Cancelable}.<br>
  * <br>
@@ -25,18 +31,41 @@ import net.minecraftforge.common.MinecraftForge;
  * <br>
  * This event is fired on the {@link MinecraftForge#EVENT_BUS}.
  **/
+// TODO: Remove in 1.20
+@Deprecated(since = "1.19.2", forRemoval = true)
 public class LivingSetAttackTargetEvent extends LivingEvent
 {
-
-    private final LivingEntity target;
+    private final ILivingTargetType targetType;
+    private final LivingEntity originalTarget;
+    
     public LivingSetAttackTargetEvent(LivingEntity entity, LivingEntity target)
     {
         super(entity);
-        this.target = target;
+        this.targetType = LivingTargetType.MOB_TARGET;        
+        this.originalTarget = target;
+    }
+    
+    public LivingSetAttackTargetEvent(LivingEntity entity, LivingEntity target, ILivingTargetType targetType)
+    {
+        super(entity);
+        this.targetType = targetType;
+        this.originalTarget = target;
     }
 
+    /**
+     * {@return the target this living entity had after changing its target to a new
+     * target, but before posting this event.}
+     */
     public LivingEntity getTarget()
     {
-        return target;
+        return originalTarget;
+    }
+    
+    /**
+     * {@return the target type of this event.}
+     */
+    public ILivingTargetType getTargetType()
+    {
+        return targetType;
     }
 }

src/test/java/net/minecraftforge/debug/entity/living/LivingSetAttackTargetEventTest.java

@@ -0,0 +1,44 @@
+package net.minecraftforge.debug.entity.living;
+
+import net.minecraft.world.entity.monster.piglin.AbstractPiglin;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.item.Items;
+import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.event.entity.living.LivingChangeTargetEvent;
+import net.minecraftforge.event.entity.living.LivingSetAttackTargetEvent;
+import net.minecraftforge.eventbus.api.SubscribeEvent;
+import net.minecraftforge.fml.common.Mod;
+
+@Mod("living_set_attack_target_event_test")
+public class LivingSetAttackTargetEventTest
+{
+    public static final boolean ENABLE = true;
+
+    public LivingSetAttackTargetEventTest()
+    {
+        if(ENABLE)
+        {
+            MinecraftForge.EVENT_BUS.register(this);
+        }
+    }
+
+    @SubscribeEvent
+    public void onLivingSetAttackTarget(LivingSetAttackTargetEvent event)
+    {
+        // Make piglins die when they start attacking a player who is not holding a stick in their main hand.
+        if (event.getTarget() instanceof Player player && event.getEntity() instanceof AbstractPiglin piglin && player.getMainHandItem().getItem() != Items.STICK)
+        {
+            event.getEntity().kill();
+        }
+    }
+    
+    @SubscribeEvent
+    public void onLivingChangeTargetEvent(LivingChangeTargetEvent event)
+    {
+        // Prevents the piglin from attacking the player if they hold a stick in their hands.
+        if(event.getNewTarget() instanceof Player player && event.getEntity() instanceof AbstractPiglin piglin && player.getMainHandItem().getItem() == Items.STICK)
+        {
+            event.setCanceled(true);
+        }
+    }
+}

src/test/resources/META-INF/mods.toml

@@ -247,6 +247,8 @@ modId="emissive_elements_test"
 [[mods]]
 modId="anvil_update_event_fix"
 [[mods]]
+modId="living_set_attack_target_event_test"
+[[mods]]
 modId="item_use_animation_test"
 [[mods]]
 modId="custom_color_resolver_test"
@@ -254,5 +256,4 @@ modId="custom_color_resolver_test"
 modId="custom_item_decorations_test"
 
 
-
 # ADD ABOVE THIS LINE