Paper/patches/server/0940-Properly-track-the-changed-item-from-dispense-events.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Mon, 12 Dec 2022 12:14:03 -0800
Subject: [PATCH] Properly track the changed item from dispense events


diff --git a/src/main/java/net/minecraft/core/dispenser/DispenseItemBehavior.java b/src/main/java/net/minecraft/core/dispenser/DispenseItemBehavior.java
index 681c38f4457fc10806c10518b16159580c0f2619..8f9b86e50717746e55232293d9e5ac05b8616aa0 100644
--- a/src/main/java/net/minecraft/core/dispenser/DispenseItemBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/DispenseItemBehavior.java
@@ -129,10 +129,14 @@ public interface DispenseItemBehavior {
                         idispensebehavior.dispense(pointer, eventStack);
                         return stack;
                     }
+                    // Paper start - track changed items in the dispense event
+                    itemstack1 = CraftItemStack.unwrap(event.getItem()); // unwrap is safe because the stack won't be modified
+                    entitytypes = ((SpawnEggItem) itemstack1.getItem()).getType(itemstack1);
+                    // Paper end - track changed item from dispense event
                 }
 
                 try {
-                    entitytypes.spawn(pointer.level(), stack, (Player) null, pointer.pos().relative(enumdirection), EntitySpawnReason.DISPENSER, enumdirection != Direction.UP, false);
+                    entitytypes.spawn(pointer.level(), itemstack1, (Player) null, pointer.pos().relative(enumdirection), EntitySpawnReason.DISPENSER, enumdirection != Direction.UP, false); // Paper - track changed item in dispense event
                 } catch (Exception exception) {
                     DispenseItemBehavior.LOGGER.error("Error while dispensing spawn egg from dispenser at {}", pointer.pos(), exception); // CraftBukkit - decompile error
                     return ItemStack.EMPTY;
@@ -186,9 +190,10 @@ public interface DispenseItemBehavior {
                 }
                 // CraftBukkit end
 
+                final ItemStack newStack = CraftItemStack.unwrap(event.getItem()); // Paper - use event itemstack (unwrap is fine here because the stack won't be modified)
                 Consumer<ArmorStand> consumer = EntityType.appendDefaultStackConfig((entityarmorstand) -> {
                     entityarmorstand.setYRot(enumdirection.toYRot());
-                }, worldserver, stack, (Player) null);
+                }, worldserver, newStack, (Player) null); // Paper - track changed items in the dispense event
                 ArmorStand entityarmorstand = (ArmorStand) EntityType.ARMOR_STAND.spawn(worldserver, consumer, blockposition, EntitySpawnReason.DISPENSER, false, false);
 
                 if (entityarmorstand != null) {
@@ -237,7 +242,7 @@ public interface DispenseItemBehavior {
                             return stack;
                         }
                     }
-                    ((Saddleable) list.get(0)).equipSaddle(itemstack1, SoundSource.BLOCKS);
+                    ((Saddleable) list.get(0)).equipSaddle(CraftItemStack.asNMSCopy(event.getItem()), SoundSource.BLOCKS); // Paper - track changed items in dispense event
                     // CraftBukkit end
                     this.setSuccess(true);
                     return stack;
@@ -330,6 +335,7 @@ public interface DispenseItemBehavior {
                 int y = blockposition.getY();
                 int z = blockposition.getZ();
                 BlockState iblockdata = worldserver.getBlockState(blockposition);
+                ItemStack dispensedItem = stack; // Paper - track changed item from the dispense event
                 // Paper start - correctly check if the bucket place will succeed
                 /* Taken from SolidBucketItem#emptyContents */
                 boolean willEmptyContentsSolidBucketItem = dispensiblecontaineritem instanceof net.minecraft.world.item.SolidBucketItem && worldserver.isInWorldBounds(blockposition) && iblockdata.isAir();
@@ -359,12 +365,15 @@ public interface DispenseItemBehavior {
                         }
                     }
 
-                    dispensiblecontaineritem = (DispensibleContainerItem) CraftItemStack.asNMSCopy(event.getItem()).getItem();
+                    // Paper start - track changed item from dispense event
+                    dispensedItem = CraftItemStack.unwrap(event.getItem()); // unwrap is safe here as the stack isn't mutated
+                    dispensiblecontaineritem = (DispensibleContainerItem) dispensedItem.getItem();
+                    // Paper end - track changed item from dispense event
                 }
                 // CraftBukkit end
 
                 if (dispensiblecontaineritem.emptyContents((Player) null, worldserver, blockposition, (BlockHitResult) null)) {
-                    dispensiblecontaineritem.checkExtraContent((Player) null, worldserver, stack, blockposition);
+                    dispensiblecontaineritem.checkExtraContent((Player) null, worldserver, dispensedItem, blockposition); // Paper - track changed item from dispense event
                     return this.consumeWithRemainder(pointer, stack, new ItemStack(Items.BUCKET));
                 } else {
                     return this.defaultDispenseItemBehavior.dispense(pointer, stack);
diff --git a/src/main/java/net/minecraft/core/dispenser/ProjectileDispenseBehavior.java b/src/main/java/net/minecraft/core/dispenser/ProjectileDispenseBehavior.java
index baf3feee740c816cf9f0470a8e56a36d02c9a29c..281439e430fb8e587549da783bdd93432f8f957f 100644
--- a/src/main/java/net/minecraft/core/dispenser/ProjectileDispenseBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/ProjectileDispenseBehavior.java
@@ -65,7 +65,7 @@ public class ProjectileDispenseBehavior extends DefaultDispenseItemBehavior {
 
         // SPIGOT-7923: Avoid create projectiles with empty item
         if (!itemstack1.isEmpty()) {
-            Projectile iprojectile = Projectile.spawnProjectileUsingShoot(this.projectileItem.asProjectile(worldserver, iposition, itemstack1, enumdirection), worldserver, itemstack1, event.getVelocity().getX(), event.getVelocity().getY(), event.getVelocity().getZ(), this.dispenseConfig.power(), this.dispenseConfig.uncertainty());
+            Projectile iprojectile = Projectile.spawnProjectileUsingShoot(this.projectileItem.asProjectile(worldserver, iposition, CraftItemStack.unwrap(event.getItem()), enumdirection), worldserver, itemstack1, event.getVelocity().getX(), event.getVelocity().getY(), event.getVelocity().getZ(), this.dispenseConfig.power(), this.dispenseConfig.uncertainty()); // Paper - track changed items in the dispense event; unwrap is safe here because all uses of the stack make their own copies
             iprojectile.projectileSource = new org.bukkit.craftbukkit.projectiles.CraftBlockProjectileSource(pointer.blockEntity());
         }
         // itemstack.shrink(1); // CraftBukkit - Handled during event processing
diff --git a/src/main/java/net/minecraft/core/dispenser/ShulkerBoxDispenseBehavior.java b/src/main/java/net/minecraft/core/dispenser/ShulkerBoxDispenseBehavior.java
index cc85e96035f7cb2e6493b1cc4748031171d7dbee..16b435216dc7c6a3f8c1c0f9e2323e6afb3a6cb9 100644
--- a/src/main/java/net/minecraft/core/dispenser/ShulkerBoxDispenseBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/ShulkerBoxDispenseBehavior.java
@@ -57,7 +57,12 @@ public class ShulkerBoxDispenseBehavior extends OptionalDispenseItemBehavior {
             // CraftBukkit end
 
             try {
-                this.setSuccess(((BlockItem) item).place(new DirectionalPlaceContext(pointer.level(), blockposition, enumdirection, stack, enumdirection1)).consumesAction());
+                // Paper start - track changed items in the dispense event
+                this.setSuccess(((BlockItem) item).place(new DirectionalPlaceContext(pointer.level(), blockposition, enumdirection, CraftItemStack.asNMSCopy(event.getItem()), enumdirection1)).consumesAction());
+                if (this.isSuccess()) {
+                    stack.shrink(1); // vanilla shrink is in the place function above, manually handle it here
+                }
+                // Paper end - track changed items in the dispense event
             } catch (Exception exception) {
                 ShulkerBoxDispenseBehavior.LOGGER.error("Error trying to place shulker box at {}", blockposition, exception);
             }