Fix several issues with EntityBreedEvent (#8677)

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.

1 files changed, 118 insertions, 0 deletions

diff --git a/patches/server/1050-Fix-several-issues-with-EntityBreedEvent.patch b/patches/server/1050-Fix-several-issues-with-EntityBreedEvent.patch
new file mode 100644
index 0000000000..40875fb77f
--- /dev/null
+++ b/patches/server/1050-Fix-several-issues-with-EntityBreedEvent.patch
@@ -0,0 +1,118 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jake Potrebic <[email protected]>
+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 be105a4460e9bf2ef4b72a307fa31291c37d5e0e..a836bfd2ea8af8098a20fb37ca25a5a613226f67 100644
+--- a/src/main/java/net/minecraft/world/entity/animal/Animal.java
++++ b/src/main/java/net/minecraft/world/entity/animal/Animal.java
+@@ -150,8 +150,9 @@ 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;
+             }
+ 
+@@ -180,10 +181,18 @@ 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();
+@@ -191,7 +200,7 @@ 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 09e9c0e55c789f03a4b64136f28154bd114db6f5..a0628b9d74c29d02bfba583edf7ee6f2cde2cff6 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
+             }
+         }
+