From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Thu, 15 Dec 2022 00:14:44 -0800
Subject: [PATCH] Fix several issues with EntityBreedEvent

Upstream did not account for different hands when storing
the breed item for later use in the event. Also they only
stored a reference to the stack, not a copy so if the stack
changed after love mode was started, the breed item in the event
also changed. Also in several places, the breed item was stored after
it was decreased by one to consume the item.

diff --git a/src/main/java/net/minecraft/world/entity/animal/Animal.java b/src/main/java/net/minecraft/world/entity/animal/Animal.java
index 907ed82fea71254d6624eda878e2668cd26422a7..f6e0eefe068fe1a9fe159b382cf94de488521728 100644
--- a/src/main/java/net/minecraft/world/entity/animal/Animal.java
+++ b/src/main/java/net/minecraft/world/entity/animal/Animal.java
@@ -152,8 +152,9 @@ public abstract class Animal extends AgeableMob {
             int i = this.getAge();
 
             if (!this.level().isClientSide && i == 0 && this.canFallInLove()) {
+                final ItemStack breedCopy = itemstack.copy(); // Paper
                 this.usePlayerItem(player, hand, itemstack);
-                this.setInLove(player);
+                this.setInLove(player, breedCopy); // Paper
                 return InteractionResult.SUCCESS;
             }
 
@@ -182,10 +183,18 @@ public abstract class Animal extends AgeableMob {
         return this.inLove <= 0;
     }
 
+    @Deprecated @io.papermc.paper.annotation.DoNotUse // Paper
     public void setInLove(@Nullable Player player) {
+        // Paper start - pass breed stack
+        this.setInLove(player, null);
+    }
+    public void setInLove(@Nullable Player player, @Nullable ItemStack breedItemCopy) {
+        if (breedItemCopy != null) this.breedItem = breedItemCopy;
+        // Paper end
         // CraftBukkit start
         EntityEnterLoveModeEvent entityEnterLoveModeEvent = CraftEventFactory.callEntityEnterLoveModeEvent(player, this, 600);
         if (entityEnterLoveModeEvent.isCancelled()) {
+            this.breedItem = null; // Paper - clear if cancelled
             return;
         }
         this.inLove = entityEnterLoveModeEvent.getTicksInLove();
@@ -193,7 +202,7 @@ public abstract class Animal extends AgeableMob {
         if (player != null) {
             this.loveCause = player.getUUID();
         }
-        this.breedItem = player.getInventory().getSelected(); // CraftBukkit
+        // Paper - set breed item in better place
 
         this.level().broadcastEntityEvent(this, (byte) 18);
     }
diff --git a/src/main/java/net/minecraft/world/entity/animal/Panda.java b/src/main/java/net/minecraft/world/entity/animal/Panda.java
index 683cc5f9f066d554383fcd30e3654ac06ec76510..17e42c49fe6f1696a0b0b4b2537cabfe565692e5 100644
--- a/src/main/java/net/minecraft/world/entity/animal/Panda.java
+++ b/src/main/java/net/minecraft/world/entity/animal/Panda.java
@@ -649,8 +649,9 @@ public class Panda extends Animal {
                 this.usePlayerItem(player, hand, itemstack);
                 this.ageUp((int) ((float) (-this.getAge() / 20) * 0.1F), true);
             } else if (!this.level().isClientSide && this.getAge() == 0 && this.canFallInLove()) {
+                final ItemStack breedCopy = itemstack.copy(); // Paper
                 this.usePlayerItem(player, hand, itemstack);
-                this.setInLove(player);
+                this.setInLove(player, breedCopy); // Paper
             } else {
                 if (this.level().isClientSide || this.isSitting() || this.isInWater()) {
                     return InteractionResult.PASS;
diff --git a/src/main/java/net/minecraft/world/entity/animal/camel/Camel.java b/src/main/java/net/minecraft/world/entity/animal/camel/Camel.java
index 1d9427da270edb447a2c8e031c4f05fe5d39603b..7dee2d1c4ce038f42334120f5dedb836f4e21723 100644
--- a/src/main/java/net/minecraft/world/entity/animal/camel/Camel.java
+++ b/src/main/java/net/minecraft/world/entity/animal/camel/Camel.java
@@ -389,7 +389,7 @@ public class Camel extends AbstractHorse implements PlayerRideableJumping, Saddl
 
             boolean bl2 = this.isTamed() && this.getAge() == 0 && this.canFallInLove();
             if (bl2) {
-                this.setInLove(player);
+                this.setInLove(player, item.copy()); // Paper
             }
 
             boolean bl3 = this.isBaby();
diff --git a/src/main/java/net/minecraft/world/entity/animal/horse/AbstractHorse.java b/src/main/java/net/minecraft/world/entity/animal/horse/AbstractHorse.java
index 8fe5a4ccf474c094b8081828c93e8973cdabb6ed..63bbb5723f587788a65cc1cdac4cea94d96f254b 100644
--- a/src/main/java/net/minecraft/world/entity/animal/horse/AbstractHorse.java
+++ b/src/main/java/net/minecraft/world/entity/animal/horse/AbstractHorse.java
@@ -513,7 +513,7 @@ public abstract class AbstractHorse extends Animal implements ContainerListener,
             b0 = 5;
             if (!this.level().isClientSide && this.isTamed() && this.getAge() == 0 && !this.isInLove()) {
                 flag = true;
-                this.setInLove(player);
+                this.setInLove(player, item.copy()); // Paper
             }
         } else if (item.is(Items.GOLDEN_APPLE) || item.is(Items.ENCHANTED_GOLDEN_APPLE)) {
             f = 10.0F;
@@ -521,7 +521,7 @@ public abstract class AbstractHorse extends Animal implements ContainerListener,
             b0 = 10;
             if (!this.level().isClientSide && this.isTamed() && this.getAge() == 0 && !this.isInLove()) {
                 flag = true;
-                this.setInLove(player);
+                this.setInLove(player, item.copy()); // Paper
             }
         }
 
diff --git a/src/main/java/net/minecraft/world/entity/animal/horse/Llama.java b/src/main/java/net/minecraft/world/entity/animal/horse/Llama.java
index 5f61c97478f005aaaaad1b027118079db7275cf7..9120663b63fc0e365e8edb359892b0db1ee97875 100644
--- a/src/main/java/net/minecraft/world/entity/animal/horse/Llama.java
+++ b/src/main/java/net/minecraft/world/entity/animal/horse/Llama.java
@@ -191,7 +191,7 @@ public class Llama extends AbstractChestedHorse implements VariantHolder<Llama.V
             f = 10.0F;
             if (this.isTamed() && this.getAge() == 0 && this.canFallInLove()) {
                 flag = true;
-                this.setInLove(player);
+                this.setInLove(player, item.copy()); // Paper
             }
         }