Paper/patches/server/0886-Fix-inconsistencies-in-dispense-events-regarding-sta.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Sun, 11 Dec 2022 23:47:22 -0800
Subject: [PATCH] Fix inconsistencies in dispense events regarding stack size

The javadocs for BlockDispenseEvent suggest the ItemStack is a single
item which is being dispensed. Before this fix, sometimes it was the whole
stack before a single item had been taken. This fixes that so the stack size
is always 1.

diff --git a/src/main/java/net/minecraft/core/dispenser/AbstractProjectileDispenseBehavior.java b/src/main/java/net/minecraft/core/dispenser/AbstractProjectileDispenseBehavior.java
index e22d71c371952e91b838d10206d3dcdf9dc8716d..155bd3d6d9c7d3cac7fd04de8210301251d1e17a 100644
--- a/src/main/java/net/minecraft/core/dispenser/AbstractProjectileDispenseBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/AbstractProjectileDispenseBehavior.java
@@ -27,7 +27,7 @@ public abstract class AbstractProjectileDispenseBehavior extends DefaultDispense
 
         // CraftBukkit start
         // iprojectile.shoot((double) enumdirection.getStepX(), (double) ((float) enumdirection.getStepY() + 0.1F), (double) enumdirection.getStepZ(), this.getPower(), this.getUncertainty());
-        ItemStack itemstack1 = stack.split(1);
+        ItemStack itemstack1 = stack.copyWithCount(1); // Paper - shrink below and single item in event
         org.bukkit.block.Block block = CraftBlock.at(worldserver, pointer.pos());
         CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
 
@@ -37,12 +37,13 @@ public abstract class AbstractProjectileDispenseBehavior extends DefaultDispense
         }
 
         if (event.isCancelled()) {
-            stack.grow(1);
+            // stack.grow(1); // Paper - shrink below
             return stack;
         }
 
+        boolean shrink = true; // Paper
         if (!event.getItem().equals(craftItem)) {
-            stack.grow(1);
+            shrink = false; // Paper - shrink below
             // Chain to handler for new item
             ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
             DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
@@ -56,7 +57,7 @@ public abstract class AbstractProjectileDispenseBehavior extends DefaultDispense
         ((Entity) iprojectile).projectileSource = new org.bukkit.craftbukkit.projectiles.CraftBlockProjectileSource(pointer.blockEntity());
         // CraftBukkit end
         worldserver.addFreshEntity(iprojectile);
-        // itemstack.shrink(1); // CraftBukkit - Handled during event processing
+        if (shrink) stack.shrink(1); // Paper - actually handle here
         return stack;
     }
 
diff --git a/src/main/java/net/minecraft/core/dispenser/BoatDispenseItemBehavior.java b/src/main/java/net/minecraft/core/dispenser/BoatDispenseItemBehavior.java
index 90e1914599b43c8bf813596b3b428d8be3bac1b5..6df0db8b4cdab23494ea34236949ece4989110a3 100644
--- a/src/main/java/net/minecraft/core/dispenser/BoatDispenseItemBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/BoatDispenseItemBehavior.java
@@ -58,7 +58,7 @@ public class BoatDispenseItemBehavior extends DefaultDispenseItemBehavior {
 
         // Object object = this.isChestBoat ? new ChestBoat(worldserver, d1, d2 + d4, d3) : new EntityBoat(worldserver, d1, d2 + d4, d3);
         // CraftBukkit start
-        ItemStack itemstack1 = stack.split(1);
+        ItemStack itemstack1 = stack.copyWithCount(1); // Paper - shrink at end and single item in event
         org.bukkit.block.Block block = CraftBlock.at(worldserver, pointer.pos());
         CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
 
@@ -68,12 +68,13 @@ public class BoatDispenseItemBehavior extends DefaultDispenseItemBehavior {
         }
 
         if (event.isCancelled()) {
-            stack.grow(1);
+            // stack.grow(1); // Paper - shrink below
             return stack;
         }
 
+        boolean shrink = true; // Paper
         if (!event.getItem().equals(craftItem)) {
-            stack.grow(1);
+            shrink = false; // Paper - shrink below
             // Chain to handler for new item
             ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
             DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
@@ -89,8 +90,7 @@ public class BoatDispenseItemBehavior extends DefaultDispenseItemBehavior {
         EntityType.createDefaultStackConfig(worldserver, stack, (Player) null).accept(object);
         ((Boat) object).setVariant(this.type);
         ((Boat) object).setYRot(enumdirection.toYRot());
-        if (!worldserver.addFreshEntity((Entity) object)) stack.grow(1); // CraftBukkit
-        // itemstack.shrink(1); // CraftBukkit - handled during event processing
+        if (worldserver.addFreshEntity((Entity) object) && shrink) stack.shrink(1); // Paper - if entity add was successful and supposed to shrink
         return stack;
     }
 
diff --git a/src/main/java/net/minecraft/core/dispenser/DispenseItemBehavior.java b/src/main/java/net/minecraft/core/dispenser/DispenseItemBehavior.java
index b65d0c2ac5b4f7eb3da85b693c354463c6f49694..dd017c33ff89a516022378160410bc41cce9222e 100644
--- a/src/main/java/net/minecraft/core/dispenser/DispenseItemBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/DispenseItemBehavior.java
@@ -217,7 +217,7 @@ public interface DispenseItemBehavior {
 
                 // CraftBukkit start
                 ServerLevel worldserver = pointer.level();
-                ItemStack itemstack1 = stack.split(1);
+                ItemStack itemstack1 = stack.copyWithCount(1); // Paper - shrink below and single item in event
                 org.bukkit.block.Block block = CraftBlock.at(worldserver, pointer.pos());
                 CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
 
@@ -227,12 +227,13 @@ public interface DispenseItemBehavior {
                 }
 
                 if (event.isCancelled()) {
-                    stack.grow(1);
+                    // stack.grow(1); // Paper - shrink below
                     return stack;
                 }
 
+                boolean shrink = true; // Paper
                 if (!event.getItem().equals(craftItem)) {
-                    stack.grow(1);
+                    shrink = false; // Paper - shrink below
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
                     DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
@@ -249,7 +250,7 @@ public interface DispenseItemBehavior {
                     return ItemStack.EMPTY;
                 }
 
-                // itemstack.shrink(1); // Handled during event processing
+                if (shrink) stack.shrink(1); // Paper - actually handle here
                 // CraftBukkit end
                 pointer.level().gameEvent((Entity) null, GameEvent.ENTITY_PLACE, pointer.pos());
                 return stack;
@@ -271,7 +272,7 @@ public interface DispenseItemBehavior {
                 ServerLevel worldserver = pointer.level();
 
                 // CraftBukkit start
-                ItemStack itemstack1 = stack.split(1);
+                ItemStack itemstack1 = stack.copyWithCount(1); // Paper - shrink below and single item in event
                 org.bukkit.block.Block block = CraftBlock.at(worldserver, pointer.pos());
                 CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
 
@@ -281,12 +282,13 @@ public interface DispenseItemBehavior {
                 }
 
                 if (event.isCancelled()) {
-                    stack.grow(1);
+                    // stack.grow(1); // Paper - shrink below
                     return stack;
                 }
 
+                boolean shrink = true; // Paper
                 if (!event.getItem().equals(craftItem)) {
-                    stack.grow(1);
+                    shrink = false; // Paper - shrink below
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
                     DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
@@ -303,7 +305,7 @@ public interface DispenseItemBehavior {
                 ArmorStand entityarmorstand = (ArmorStand) EntityType.ARMOR_STAND.spawn(worldserver, stack.getTag(), consumer, blockposition, MobSpawnType.DISPENSER, false, false);
 
                 if (entityarmorstand != null) {
-                    // itemstack.shrink(1); // CraftBukkit - Handled during event processing
+                    if (shrink) stack.shrink(1); // Paper - actually handle here
                 }
 
                 return stack;
@@ -325,7 +327,7 @@ public interface DispenseItemBehavior {
 
                 if (!list.isEmpty()) {
                     // CraftBukkit start
-                    ItemStack itemstack1 = stack.split(1);
+                    ItemStack itemstack1 = stack.copyWithCount(1); // Paper - shrink below and single item in event
                     Level world = pointer.level();
                     org.bukkit.block.Block block = CraftBlock.at(world, pointer.pos());
                     CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
@@ -336,12 +338,13 @@ public interface DispenseItemBehavior {
                     }
 
                     if (event.isCancelled()) {
-                        stack.grow(1);
+                        // stack.grow(1); // Paper - shrink below
                         return stack;
                     }
 
+                    boolean shrink = true; // Paper
                     if (!event.getItem().equals(craftItem)) {
-                        stack.grow(1);
+                        shrink = false; // Paper - shrink below
                         // Chain to handler for new item
                         ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
                         DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
@@ -352,7 +355,7 @@ public interface DispenseItemBehavior {
                     }
                     // CraftBukkit end
                     ((Saddleable) list.get(0)).equipSaddle(SoundSource.BLOCKS, CraftItemStack.asNMSCopy(event.getItem())); // Paper - Fix saddles losing nbt data - MC-191591
-                    // itemstack.shrink(1); // CraftBukkit - handled above
+                    if (shrink) stack.shrink(1); // Paper - actually handle here
                     this.setSuccess(true);
                     return stack;
                 } else {
@@ -380,7 +383,7 @@ public interface DispenseItemBehavior {
                 } while (!entityhorseabstract.isArmor(stack) || entityhorseabstract.isWearingArmor() || !entityhorseabstract.isTamed());
 
                 // CraftBukkit start
-                ItemStack itemstack1 = stack.split(1);
+                ItemStack itemstack1 = stack.copyWithCount(1); // Paper - shrink below and single item in event
                 Level world = pointer.level();
                 org.bukkit.block.Block block = CraftBlock.at(world, pointer.pos());
                 CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
@@ -391,12 +394,13 @@ public interface DispenseItemBehavior {
                 }
 
                 if (event.isCancelled()) {
-                    stack.grow(1);
+                    // stack.grow(1); // Paper - shrink below
                     return stack;
                 }
 
+                boolean shrink = true; // Paper
                 if (!event.getItem().equals(craftItem)) {
-                    stack.grow(1);
+                    shrink = false; // Paper - shrink below
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
                     DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
@@ -406,6 +410,7 @@ public interface DispenseItemBehavior {
                     }
                 }
 
+                if (shrink) stack.shrink(1); // Paper - shrink here
                 entityhorseabstract.getSlot(401).set(CraftItemStack.asNMSCopy(event.getItem()));
                 // CraftBukkit end
                 this.setSuccess(true);
@@ -452,7 +457,7 @@ public interface DispenseItemBehavior {
                     entityhorsechestedabstract = (AbstractChestedHorse) iterator1.next();
                     // CraftBukkit start
                 } while (!entityhorsechestedabstract.isTamed());
-                ItemStack itemstack1 = stack.split(1);
+                ItemStack itemstack1 = stack.copyWithCount(1); // Paper - shrink below
                 Level world = pointer.level();
                 org.bukkit.block.Block block = CraftBlock.at(world, pointer.pos());
                 CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
@@ -463,10 +468,13 @@ public interface DispenseItemBehavior {
                 }
 
                 if (event.isCancelled()) {
+                    // stack.grow(1); // Paper - shrink below (this was actually missing and should be here, added it commented out just for less confusion)
                     return stack;
                 }
 
+                boolean shrink = true; // Paper
                 if (!event.getItem().equals(craftItem)) {
+                    shrink = false; // Paper - shrink below (this was actually missing and should be here, added it commented out just for less confusion)
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
                     DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
@@ -478,7 +486,7 @@ public interface DispenseItemBehavior {
                 entityhorsechestedabstract.getSlot(499).set(CraftItemStack.asNMSCopy(event.getItem()));
                 // CraftBukkit end
 
-                // itemstack.shrink(1); // CraftBukkit - handled above
+                if (shrink) stack.shrink(1); // Paper - actually handle here
                 this.setSuccess(true);
                 return stack;
             }
@@ -489,7 +497,7 @@ public interface DispenseItemBehavior {
                 Direction enumdirection = (Direction) pointer.state().getValue(DispenserBlock.FACING);
                 // CraftBukkit start
                 ServerLevel worldserver = pointer.level();
-                ItemStack itemstack1 = stack.split(1);
+                ItemStack itemstack1 = stack.copyWithCount(1); // Paper - shrink below and single item in event
                 org.bukkit.block.Block block = CraftBlock.at(worldserver, pointer.pos());
                 CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
 
@@ -499,12 +507,13 @@ public interface DispenseItemBehavior {
                 }
 
                 if (event.isCancelled()) {
-                    stack.grow(1);
+                    // stack.grow(1); // Paper - shrink below
                     return stack;
                 }
 
+                boolean shrink = true; // Paper
                 if (!event.getItem().equals(craftItem)) {
-                    stack.grow(1);
+                    shrink = false; // Paper - shrink below
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
                     DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
@@ -521,7 +530,7 @@ public interface DispenseItemBehavior {
 
                 entityfireworks.shoot((double) enumdirection.getStepX(), (double) enumdirection.getStepY(), (double) enumdirection.getStepZ(), 0.5F, 1.0F);
                 pointer.level().addFreshEntity(entityfireworks);
-                // itemstack.shrink(1); // Handled during event processing
+                if (shrink) stack.shrink(1); // Paper - actually handle here
                 // CraftBukkit end
                 return stack;
             }
@@ -546,7 +555,7 @@ public interface DispenseItemBehavior {
                 double d5 = randomsource.triangle((double) enumdirection.getStepZ(), 0.11485000000000001D);
 
                 // CraftBukkit start
-                ItemStack itemstack1 = stack.split(1);
+                ItemStack itemstack1 = stack.copyWithCount(1); // Paper - shrink below and single item in event
                 org.bukkit.block.Block block = CraftBlock.at(worldserver, pointer.pos());
                 CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
 
@@ -556,12 +565,13 @@ public interface DispenseItemBehavior {
                 }
 
                 if (event.isCancelled()) {
-                    stack.grow(1);
+                    // stack.grow(1); // Paper - shrink at end
                     return stack;
                 }
 
+                boolean shrink = true; // Paper
                 if (!event.getItem().equals(craftItem)) {
-                    stack.grow(1);
+                    shrink = false; // Paper - shrink at end
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
                     DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
@@ -576,7 +586,7 @@ public interface DispenseItemBehavior {
                 entitysmallfireball.projectileSource = new org.bukkit.craftbukkit.projectiles.CraftBlockProjectileSource(pointer.blockEntity());
 
                 worldserver.addFreshEntity(entitysmallfireball);
-                // itemstack.shrink(1); // Handled during event processing
+                if (shrink) stack.shrink(1); // Paper - actually handle here
                 // CraftBukkit end
                 return stack;
             }
@@ -620,7 +630,7 @@ public interface DispenseItemBehavior {
                 BlockState iblockdata = worldserver.getBlockState(blockposition);
                 if (iblockdata.isAir() || iblockdata.canBeReplaced() || (dispensiblecontaineritem instanceof BucketItem && iblockdata.getBlock() instanceof LiquidBlockContainer && ((LiquidBlockContainer) iblockdata.getBlock()).canPlaceLiquid((Player) null, worldserver, blockposition, iblockdata, ((BucketItem) dispensiblecontaineritem).content))) {
                     org.bukkit.block.Block block = CraftBlock.at(worldserver, pointer.pos());
-                    CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack);
+                    CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack.copyWithCount(1)); // Paper - single item in event
 
                     BlockDispenseEvent event = new BlockDispenseEvent(block, craftItem.clone(), new org.bukkit.util.Vector(x, y, z));
                     if (!DispenserBlock.eventFired) {
@@ -631,6 +641,7 @@ public interface DispenseItemBehavior {
                         return stack;
                     }
 
+                    boolean shrink = true; // Paper
                     if (!event.getItem().equals(craftItem)) {
                         // Chain to handler for new item
                         ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
@@ -694,7 +705,7 @@ public interface DispenseItemBehavior {
 
                         // CraftBukkit start
                         org.bukkit.block.Block bukkitBlock = CraftBlock.at(worldserver, pointer.pos());
-                        CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack);
+                        CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack.copyWithCount(1)); // Paper - single item in event
 
                         BlockDispenseEvent event = new BlockDispenseEvent(bukkitBlock, craftItem.clone(), new org.bukkit.util.Vector(blockposition.getX(), blockposition.getY(), blockposition.getZ()));
                         if (!DispenserBlock.eventFired) {
@@ -752,7 +763,9 @@ public interface DispenseItemBehavior {
                     return stack;
                 }
 
+                boolean shrink = true; // Paper
                 if (!event.getItem().equals(craftItem)) {
+                    shrink = false; // Paper - shrink below (this was actually missing and should be here, added it commented out just for less confusion)
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
                     DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
@@ -802,7 +815,7 @@ public interface DispenseItemBehavior {
                 BlockPos blockposition = pointer.pos().relative((Direction) pointer.state().getValue(DispenserBlock.FACING));
                 // CraftBukkit start
                 org.bukkit.block.Block block = CraftBlock.at(worldserver, pointer.pos());
-                CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack);
+                CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack.copyWithCount(1)); // Paper - single item in event
 
                 BlockDispenseEvent event = new BlockDispenseEvent(block, craftItem.clone(), new org.bukkit.util.Vector(0, 0, 0));
                 if (!DispenserBlock.eventFired) {
@@ -813,6 +826,7 @@ public interface DispenseItemBehavior {
                     return stack;
                 }
 
+                boolean shrink = true; // Paper
                 if (!event.getItem().equals(craftItem)) {
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
@@ -868,7 +882,7 @@ public interface DispenseItemBehavior {
                 // CraftBukkit start
                 // EntityTNTPrimed entitytntprimed = new EntityTNTPrimed(worldserver, (double) blockposition.getX() + 0.5D, (double) blockposition.getY(), (double) blockposition.getZ() + 0.5D, (EntityLiving) null);
 
-                ItemStack itemstack1 = stack.split(1);
+                ItemStack itemstack1 = stack.copyWithCount(1); // Paper - shrink at end and single item in event
                 org.bukkit.block.Block block = CraftBlock.at(worldserver, pointer.pos());
                 CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
 
@@ -878,12 +892,13 @@ public interface DispenseItemBehavior {
                 }
 
                 if (event.isCancelled()) {
-                    stack.grow(1);
+                    // stack.grow(1); // Paper - shrink below
                     return stack;
                 }
 
+                boolean shrink = true; // Paper
                 if (!event.getItem().equals(craftItem)) {
-                    stack.grow(1);
+                    shrink = false; // Paper - shrink below
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
                     DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
@@ -899,7 +914,7 @@ public interface DispenseItemBehavior {
                 worldserver.addFreshEntity(entitytntprimed);
                 worldserver.playSound((Player) null, entitytntprimed.getX(), entitytntprimed.getY(), entitytntprimed.getZ(), SoundEvents.TNT_PRIMED, SoundSource.BLOCKS, 1.0F, 1.0F);
                 worldserver.gameEvent((Entity) null, GameEvent.ENTITY_PLACE, blockposition);
-                // itemstack.shrink(1); // CraftBukkit - handled above
+                if (shrink) stack.shrink(1); // Paper - actually handle here
                 return stack;
             }
         });
@@ -926,7 +941,7 @@ public interface DispenseItemBehavior {
 
                 // CraftBukkit start
                 org.bukkit.block.Block bukkitBlock = CraftBlock.at(worldserver, pointer.pos());
-                CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack);
+                CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack.copyWithCount(1)); // Paper - single item in event
 
                 BlockDispenseEvent event = new BlockDispenseEvent(bukkitBlock, craftItem.clone(), new org.bukkit.util.Vector(blockposition.getX(), blockposition.getY(), blockposition.getZ()));
                 if (!DispenserBlock.eventFired) {
@@ -934,9 +949,11 @@ public interface DispenseItemBehavior {
                 }
 
                 if (event.isCancelled()) {
+                    // stack.grow(1); // Paper - shrink below (this was actually missing and should be here, added it commented out just for less confusion)
                     return stack;
                 }
 
+                boolean shrink = true; // Paper
                 if (!event.getItem().equals(craftItem)) {
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
@@ -975,7 +992,7 @@ public interface DispenseItemBehavior {
 
                 // CraftBukkit start
                 org.bukkit.block.Block bukkitBlock = CraftBlock.at(worldserver, pointer.pos());
-                CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack);
+                CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack.copyWithCount(1)); // Paper - single item in event
 
                 BlockDispenseEvent event = new BlockDispenseEvent(bukkitBlock, craftItem.clone(), new org.bukkit.util.Vector(blockposition.getX(), blockposition.getY(), blockposition.getZ()));
                 if (!DispenserBlock.eventFired) {
@@ -986,6 +1003,7 @@ public interface DispenseItemBehavior {
                     return stack;
                 }
 
+                boolean shrink = true; // Paper
                 if (!event.getItem().equals(craftItem)) {
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
@@ -1048,7 +1066,7 @@ public interface DispenseItemBehavior {
 
                 // CraftBukkit start
                 org.bukkit.block.Block bukkitBlock = CraftBlock.at(worldserver, pointer.pos());
-                CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack);
+                CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack.copyWithCount(1)); // Paper - only single item in event
 
                 BlockDispenseEvent event = new BlockDispenseEvent(bukkitBlock, craftItem.clone(), new org.bukkit.util.Vector(blockposition.getX(), blockposition.getY(), blockposition.getZ()));
                 if (!DispenserBlock.eventFired) {
@@ -1059,6 +1077,7 @@ public interface DispenseItemBehavior {
                     return stack;
                 }
 
+                boolean shrink = true; // Paper
                 if (!event.getItem().equals(craftItem)) {
                     // Chain to handler for new item
                     ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
diff --git a/src/main/java/net/minecraft/core/dispenser/ShulkerBoxDispenseBehavior.java b/src/main/java/net/minecraft/core/dispenser/ShulkerBoxDispenseBehavior.java
index f84987c36a16df19286d6f1badfb1ffb9cc7e770..6f2adf2334e35e8a617a4ced0c1af2abf32bbd8d 100644
--- a/src/main/java/net/minecraft/core/dispenser/ShulkerBoxDispenseBehavior.java
+++ b/src/main/java/net/minecraft/core/dispenser/ShulkerBoxDispenseBehavior.java
@@ -34,7 +34,7 @@ public class ShulkerBoxDispenseBehavior extends OptionalDispenseItemBehavior {
 
             // CraftBukkit start
             org.bukkit.block.Block bukkitBlock = CraftBlock.at(pointer.level(), pointer.pos());
-            CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack);
+            CraftItemStack craftItem = CraftItemStack.asCraftMirror(stack.copyWithCount(1)); // Paper - single item in event
 
             BlockDispenseEvent event = new BlockDispenseEvent(bukkitBlock, craftItem.clone(), new org.bukkit.util.Vector(blockposition.getX(), blockposition.getY(), blockposition.getZ()));
             if (!DispenserBlock.eventFired) {
diff --git a/src/main/java/net/minecraft/world/item/ArmorItem.java b/src/main/java/net/minecraft/world/item/ArmorItem.java
index a745dc02ae25bcf10cee954b6e53f8b106fd045d..42d87800a328f71c5127ce5599ca4c71cc9bb1cd 100644
--- a/src/main/java/net/minecraft/world/item/ArmorItem.java
+++ b/src/main/java/net/minecraft/world/item/ArmorItem.java
@@ -62,7 +62,7 @@ public class ArmorItem extends Item implements Equipable {
         } else {
             LivingEntity entityliving = (LivingEntity) list.get(0);
             EquipmentSlot enumitemslot = Mob.getEquipmentSlotForItem(armor);
-            ItemStack itemstack1 = armor.split(1);
+            ItemStack itemstack1 = armor.copyWithCount(1); // Paper - shrink below and single item in event
             // CraftBukkit start
             Level world = pointer.level();
             org.bukkit.block.Block block = CraftBlock.at(world, pointer.pos());
@@ -74,12 +74,13 @@ public class ArmorItem extends Item implements Equipable {
             }
 
             if (event.isCancelled()) {
-                armor.grow(1);
+                // armor.grow(1); // Paper - shrink below
                 return false;
             }
 
+            boolean shrink = true; // Paper
             if (!event.getItem().equals(craftItem)) {
-                armor.grow(1);
+                shrink = false; // Paper - shrink below
                 // Chain to handler for new item
                 ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
                 DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
@@ -96,6 +97,7 @@ public class ArmorItem extends Item implements Equipable {
                 ((Mob) entityliving).setPersistenceRequired();
             }
 
+            if (shrink) armor.shrink(1); // Paper
             return true;
         }
     }
diff --git a/src/main/java/net/minecraft/world/item/MinecartItem.java b/src/main/java/net/minecraft/world/item/MinecartItem.java
index 9bcca21ba03dc838f3e857018adee9506d8bb6a3..3aa73cd44aa8c86b78c35bc1788e4f83018c49ed 100644
--- a/src/main/java/net/minecraft/world/item/MinecartItem.java
+++ b/src/main/java/net/minecraft/world/item/MinecartItem.java
@@ -65,7 +65,7 @@ public class MinecartItem extends Item {
 
             // CraftBukkit start
             // EntityMinecartAbstract entityminecartabstract = EntityMinecartAbstract.createMinecart(worldserver, d0, d1 + d3, d2, ((ItemMinecart) itemstack.getItem()).type);
-            ItemStack itemstack1 = stack.split(1);
+            ItemStack itemstack1 = stack.copyWithCount(1); // Paper - shrink below and single item in event
             org.bukkit.block.Block block2 = CraftBlock.at(worldserver, pointer.pos());
             CraftItemStack craftItem = CraftItemStack.asCraftMirror(itemstack1);
 
@@ -75,12 +75,13 @@ public class MinecartItem extends Item {
             }
 
             if (event.isCancelled()) {
-                stack.grow(1);
+                // stack.grow(1); // Paper - shrink below
                 return stack;
             }
 
+            boolean shrink = true; // Paper
             if (!event.getItem().equals(craftItem)) {
-                stack.grow(1);
+                shrink = false; // Paper - shrink below
                 // Chain to handler for new item
                 ItemStack eventStack = CraftItemStack.asNMSCopy(event.getItem());
                 DispenseItemBehavior idispensebehavior = (DispenseItemBehavior) DispenserBlock.DISPENSER_REGISTRY.get(eventStack.getItem());
@@ -93,8 +94,7 @@ public class MinecartItem extends Item {
             itemstack1 = CraftItemStack.asNMSCopy(event.getItem());
             AbstractMinecart entityminecartabstract = AbstractMinecart.createMinecart(worldserver, event.getVelocity().getX(), event.getVelocity().getY(), event.getVelocity().getZ(), ((MinecartItem) itemstack1.getItem()).type, itemstack1, (Player) null);
 
-            if (!worldserver.addFreshEntity(entityminecartabstract)) stack.grow(1);
-            // itemstack.shrink(1); // CraftBukkit - handled during event processing
+            if (worldserver.addFreshEntity(entityminecartabstract) && shrink) stack.shrink(1); // Paper - actually handle here
             // CraftBukkit end
             return stack;
         }