From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: violetc <58360096+s-yh-china@users.noreply.github.com>
Date: Wed, 14 Dec 2022 14:47:06 +0800
Subject: [PATCH] Stackable ShulkerBoxes

This patch is Powered by fabric-carpet(https://github.com/gnembon/fabric-carpet) and plusls-carpet-addition(https://github.com/plusls/plusls-carpet-addition)

diff --git a/net/minecraft/commands/arguments/item/ItemInput.java b/net/minecraft/commands/arguments/item/ItemInput.java
index 643797124fe5a4489d0b7419b7e600c04f283ef2..51971a4ef18ab048dc576c26652982d57e440dc0 100644
--- a/net/minecraft/commands/arguments/item/ItemInput.java
+++ b/net/minecraft/commands/arguments/item/ItemInput.java
@@ -39,11 +39,13 @@ public class ItemInput {
     public ItemStack createItemStack(int count, boolean allowOversizedStacks) throws CommandSyntaxException {
         ItemStack itemStack = new ItemStack(this.item, count);
         itemStack.applyComponents(this.components);
-        if (allowOversizedStacks && count > itemStack.getMaxStackSize()) {
-            throw ERROR_STACK_TOO_BIG.create(this.getItemName(), itemStack.getMaxStackSize());
+        // Leaves start - stackable shulker boxes
+        if (allowOversizedStacks && count > org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(itemStack)) {
+            throw ERROR_STACK_TOO_BIG.create(this.getItemName(), org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(itemStack));
         } else {
             return itemStack;
         }
+        // Leaves end - stackable shulker boxes
     }
 
     public String serialize(HolderLookup.Provider levelRegistry) {
diff --git a/net/minecraft/server/commands/GiveCommand.java b/net/minecraft/server/commands/GiveCommand.java
index b81f98738ef166336e4cc3092b6ba63f385b68e3..e800abc1149db77bc9b7ee1aabd17526ebda377c 100644
--- a/net/minecraft/server/commands/GiveCommand.java
+++ b/net/minecraft/server/commands/GiveCommand.java
@@ -52,7 +52,7 @@ public class GiveCommand {
     private static int giveItem(CommandSourceStack source, ItemInput item, Collection<ServerPlayer> targets, int count) throws CommandSyntaxException {
         ItemStack itemStack = item.createItemStack(1, false);
         final Component displayName = itemStack.getDisplayName(); // Paper - get display name early
-        int maxStackSize = itemStack.getMaxStackSize();
+        int maxStackSize = org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(itemStack); // Leaves - stackable shulker boxes
         int i = maxStackSize * 100;
         if (count > i) {
             source.sendFailure(Component.translatable("commands.give.failed.toomanyitems", i, itemStack.getDisplayName()));
diff --git a/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/net/minecraft/server/network/ServerGamePacketListenerImpl.java
index 9041830c19e2899479e1519488faba5c416ccd88..ca814ebdb05ca3af138bf087f26d2cf50baf3b9c 100644
--- a/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+++ b/net/minecraft/server/network/ServerGamePacketListenerImpl.java
@@ -2974,7 +2974,7 @@ public class ServerGamePacketListenerImpl
                                             } else if (slot.mayPlace(cursor)) {
                                                 if (ItemStack.isSameItemSameComponents(clickedItem, cursor)) {
                                                     int toPlace = packet.buttonNum() == 0 ? cursor.getCount() : 1;
-                                                    toPlace = Math.min(toPlace, clickedItem.getMaxStackSize() - clickedItem.getCount());
+                                                    toPlace = Math.min(toPlace, org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(clickedItem) - clickedItem.getCount()); // Leaves - stackable shulker boxes
                                                     toPlace = Math.min(toPlace, slot.container.getMaxStackSize() - clickedItem.getCount());
                                                     if (toPlace == 1) {
                                                         action = InventoryAction.PLACE_ONE;
@@ -3010,7 +3010,7 @@ public class ServerGamePacketListenerImpl
                                                 }
                                             } else if (ItemStack.isSameItemSameComponents(cursor, clickedItem)) {
                                                 if (clickedItem.getCount() >= 0) {
-                                                    if (clickedItem.getCount() + cursor.getCount() <= cursor.getMaxStackSize()) {
+                                                    if (clickedItem.getCount() + cursor.getCount() <= org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(cursor)) { // Leaves - stackable shulker boxes
                                                         // As of 1.5, this is result slots only
                                                         action = InventoryAction.PICKUP_ALL;
                                                     }
@@ -3269,6 +3269,7 @@ public class ServerGamePacketListenerImpl
                         this.player.containerMenu.broadcastFullState();
                     } else {
                         this.player.containerMenu.broadcastChanges();
+                        if (org.leavesmc.leaves.LeavesConfig.modify.shulkerBoxStackSize > 1) this.player.containerMenu.broadcastCarriedItem(); // Leaves - stackable shulker boxes - force send carried item
                     }
                     if (io.papermc.paper.configuration.GlobalConfiguration.get().unsupportedSettings.updateEquipmentOnPlayerActions) this.player.detectEquipmentUpdates(); // Paper - Force update attributes.
                 }
@@ -3381,7 +3382,7 @@ public class ServerGamePacketListenerImpl
             }
 
             boolean flag1 = packet.slotNum() >= 1 && packet.slotNum() <= 45;
-            boolean flag2 = itemStack.isEmpty() || itemStack.getCount() <= itemStack.getMaxStackSize();
+            boolean flag2 = itemStack.isEmpty() || itemStack.getCount() <= org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(itemStack); // Leaves - stackable shulker boxes
             if (flag || (flag1 && !ItemStack.matches(this.player.inventoryMenu.getSlot(packet.slotNum()).getItem(), packet.itemStack()))) { // Insist on valid slot
                 // CraftBukkit start - Call click event
                 org.bukkit.inventory.InventoryView inventory = this.player.inventoryMenu.getBukkitView();
@@ -3423,6 +3424,7 @@ public class ServerGamePacketListenerImpl
                 this.player.inventoryMenu.getSlot(packet.slotNum()).setByPlayer(itemStack);
                 this.player.inventoryMenu.setRemoteSlot(packet.slotNum(), itemStack);
                 this.player.inventoryMenu.broadcastChanges();
+                if (org.leavesmc.leaves.LeavesConfig.modify.shulkerBoxStackSize > 1) this.player.containerMenu.sendSingleSlot(packet.slotNum(), itemStack); // Leaves - stackable shulker boxes - force send carried item
                 if (io.papermc.paper.configuration.GlobalConfiguration.get().unsupportedSettings.updateEquipmentOnPlayerActions) this.player.detectEquipmentUpdates(); // Paper - Force update attributes.
             } else if (flag && flag2) {
                 if (this.dropSpamThrottler.isUnderThreshold()) {
diff --git a/net/minecraft/world/Container.java b/net/minecraft/world/Container.java
index b382665cc125b8b5c0938e5e55984e4bf91d37ff..f575b464a8ce430646cb872ae6206a9a0677736b 100644
--- a/net/minecraft/world/Container.java
+++ b/net/minecraft/world/Container.java
@@ -32,6 +32,12 @@ public interface Container extends Clearable, Iterable<ItemStack> {
         return Math.min(this.getMaxStackSize(), stack.getMaxStackSize());
     }
 
+    // Leaves start - stackable shulker boxes
+    default int getMaxStackLeaves(ItemStack stack) {
+        return Math.min(this.getMaxStackSize(), org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(stack));
+    }
+    // Leaves end - stackable shulker boxes
+
     void setChanged();
 
     boolean stillValid(Player player);
diff --git a/net/minecraft/world/SimpleContainer.java b/net/minecraft/world/SimpleContainer.java
index 133e042371bcf84f1935903ec57d204e3b7abd84..201599988e20219b6a99bf1594ad6c0c19e09038 100644
--- a/net/minecraft/world/SimpleContainer.java
+++ b/net/minecraft/world/SimpleContainer.java
@@ -211,7 +211,7 @@ public class SimpleContainer implements Container, StackedContentsCompatible {
     @Override
     public void setItem(int index, ItemStack stack) {
         this.items.set(index, stack);
-        stack.limitSize(this.getMaxStackSize(stack));
+        stack.limitSize(this.getMaxStackLeaves(stack)); // Leaves - stackable shulker boxes
         this.setChanged();
     }
 
@@ -286,7 +286,7 @@ public class SimpleContainer implements Container, StackedContentsCompatible {
     }
 
     private void moveItemsBetweenStacks(ItemStack stack, ItemStack other) {
-        int maxStackSize = this.getMaxStackSize(other);
+        int maxStackSize = this.getMaxStackLeaves(other); // Leaves - stackable shulker boxes
         int min = Math.min(stack.getCount(), maxStackSize - other.getCount());
         if (min > 0) {
             other.grow(min);
diff --git a/net/minecraft/world/entity/item/ItemEntity.java b/net/minecraft/world/entity/item/ItemEntity.java
index 6c0ebfb2be4e8b884456a2aa3d5fdc87e45a0e3c..b0e60d1d2a44bb35c87c35e82a172a38406b6c54 100644
--- a/net/minecraft/world/entity/item/ItemEntity.java
+++ b/net/minecraft/world/entity/item/ItemEntity.java
@@ -281,10 +281,52 @@ public class ItemEntity extends Entity implements TraceableEntity {
 
     private boolean isMergable() {
         ItemStack item = this.getItem();
-        return this.isAlive() && this.pickupDelay != 32767 && this.age != -32768 && this.age < this.despawnRate && item.getCount() < item.getMaxStackSize(); // Paper - Alternative item-despawn-rate
+        return this.isAlive() && this.pickupDelay != 32767 && this.age != -32768 && this.age < this.despawnRate && item.getCount() < org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(item); // Paper - Alternative item-despawn-rate // Leaves - stackable shulker boxes
     }
 
+    // Leaves end - stackable shulker boxes
+    private boolean tryStackShulkerBoxes(ItemEntity other) {
+        ItemStack selfStack = this.getItem();
+        if (org.leavesmc.leaves.LeavesConfig.modify.shulkerBoxStackSize == 1 ||
+                !(selfStack.getItem() instanceof net.minecraft.world.item.BlockItem blockItem) ||
+                !(blockItem.getBlock() instanceof net.minecraft.world.level.block.ShulkerBoxBlock)
+        ) {
+            return false;
+        }
+
+        ItemStack otherStack = other.getItem();
+        if (selfStack.getItem() == otherStack.getItem()
+                && org.leavesmc.leaves.util.ShulkerBoxUtils.shulkerBoxNoItem(selfStack)
+                && org.leavesmc.leaves.util.ShulkerBoxUtils.shulkerBoxNoItem(otherStack)
+                && Objects.equals(selfStack.getComponents(), otherStack.getComponents()) // empty block entity tags are cleaned up when spawning
+                && selfStack.getCount() != org.leavesmc.leaves.LeavesConfig.modify.shulkerBoxStackSize) {
+            int amount = Math.min(otherStack.getCount(), org.leavesmc.leaves.LeavesConfig.modify.shulkerBoxStackSize - selfStack.getCount());
+
+            selfStack.grow(amount);
+            this.setItem(selfStack);
+
+            this.pickupDelay = Math.max(other.pickupDelay, this.pickupDelay);
+            this.age = Math.min(other.getAge(), this.age);
+
+            otherStack.shrink(amount);
+            if (otherStack.isEmpty()) {
+                other.discard();
+            }
+            else {
+                other.setItem(otherStack);
+            }
+            return true;
+        }
+        return false;
+    }
+    // Leaves end - stackable shulker boxes
+
     private void tryToMerge(ItemEntity itemEntity) {
+        // Leaves start - stackable shulker boxes
+        if (tryStackShulkerBoxes(itemEntity)) {
+            return;
+        }
+        // Leaves end - stackable shulker boxes
         ItemStack item = this.getItem();
         ItemStack item1 = itemEntity.getItem();
         if (Objects.equals(this.target, itemEntity.target) && areMergable(item, item1)) {
diff --git a/net/minecraft/world/entity/player/Inventory.java b/net/minecraft/world/entity/player/Inventory.java
index d9cb4f0ed0c4f63362c837aeef3c4194911455c9..57bf2819271b3293a065b58d31b609f8463811b4 100644
--- a/net/minecraft/world/entity/player/Inventory.java
+++ b/net/minecraft/world/entity/player/Inventory.java
@@ -148,10 +148,12 @@ public class Inventory implements Container, Nameable {
     }
 
     private boolean hasRemainingSpaceForItem(ItemStack destination, ItemStack origin) {
+        // Leaves start - stackable shulker boxes
         return !destination.isEmpty()
-            && destination.isStackable()
-            && destination.getCount() < this.getMaxStackSize(destination)
+            && org.leavesmc.leaves.util.ShulkerBoxUtils.isStackable(destination)
+            && destination.getCount() < org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(destination)
             && ItemStack.isSameItemSameComponents(destination, origin); // Paper - check if itemstack is stackable first
+        // Leaves end - stackable shulker boxes
     }
 
     // CraftBukkit start - Watch method above! :D
@@ -164,7 +166,7 @@ public class Inventory implements Container, Nameable {
             }
 
             if (this.hasRemainingSpaceForItem(itemInSlot, itemStack)) {
-                remains -= (itemInSlot.getMaxStackSize() < this.getMaxStackSize() ? itemInSlot.getMaxStackSize() : this.getMaxStackSize()) - itemInSlot.getCount();
+                remains -= (org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(itemInSlot) < this.getMaxStackSize() ? org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(itemInSlot) : this.getMaxStackSize()) - itemInSlot.getCount(); // Leaves - stackable shulker boxes
             }
             if (remains <= 0) {
                 return itemStack.getCount();
@@ -173,7 +175,7 @@ public class Inventory implements Container, Nameable {
 
         ItemStack itemInOffhand = this.equipment.get(EquipmentSlot.OFFHAND);
         if (this.hasRemainingSpaceForItem(itemInOffhand, itemStack)) {
-            remains -= (itemInOffhand.getMaxStackSize() < this.getMaxStackSize() ? itemInOffhand.getMaxStackSize() : this.getMaxStackSize()) - itemInOffhand.getCount();
+            remains -= (org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(itemInOffhand) < this.getMaxStackSize() ? org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(itemInOffhand) : this.getMaxStackSize()) - itemInOffhand.getCount(); // Leaves - stackable shulker boxes
         }
         if (remains <= 0) {
             return itemStack.getCount();
@@ -297,7 +299,7 @@ public class Inventory implements Container, Nameable {
             this.setItem(slot, item);
         }
 
-        int i = this.getMaxStackSize(item) - item.getCount();
+        int i = this.getMaxStackLeaves(item) - item.getCount(); // Leaves - stackable shulker boxes
         int min = Math.min(count, i);
         if (min == 0) {
             return count;
@@ -403,7 +405,7 @@ public class Inventory implements Container, Nameable {
                 break;
             }
 
-            int i = stack.getMaxStackSize() - this.getItem(slotWithRemainingSpace).getCount();
+            int i = org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(stack) - this.getItem(slotWithRemainingSpace).getCount(); // Leaves - stackable shulker boxes
             if (this.add(slotWithRemainingSpace, stack.split(i)) && sendPacket && this.player instanceof ServerPlayer serverPlayer) {
                 serverPlayer.connection.send(this.createInventoryUpdatePacket(slotWithRemainingSpace));
             }
diff --git a/net/minecraft/world/entity/player/StackedItemContents.java b/net/minecraft/world/entity/player/StackedItemContents.java
index 83ccde54c625d40dc595e000c533f60aa929bd5a..1b92676459468d42931b84e5ceb19e8d30302f06 100644
--- a/net/minecraft/world/entity/player/StackedItemContents.java
+++ b/net/minecraft/world/entity/player/StackedItemContents.java
@@ -23,7 +23,7 @@ public class StackedItemContents {
     }
 
     public void accountStack(ItemStack stack) {
-        this.accountStack(stack, stack.getMaxStackSize());
+        this.accountStack(stack, org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(stack)); // Leaves - stackable shulker boxes
     }
 
     public void accountStack(ItemStack stack, int maxStackSize) {
diff --git a/net/minecraft/world/entity/vehicle/ContainerEntity.java b/net/minecraft/world/entity/vehicle/ContainerEntity.java
index feebd1610ebd3c26a337259c14f5c774dc72b937..7df6ff842e41763aec2d88d1f8a5f7503932d905 100644
--- a/net/minecraft/world/entity/vehicle/ContainerEntity.java
+++ b/net/minecraft/world/entity/vehicle/ContainerEntity.java
@@ -163,7 +163,7 @@ public interface ContainerEntity extends Container, MenuProvider {
     default void setChestVehicleItem(int slot, ItemStack stack) {
         this.unpackChestVehicleLootTable(null);
         this.getItemStacks().set(slot, stack);
-        stack.limitSize(this.getMaxStackSize(stack));
+        stack.limitSize(this.getMaxStackLeaves(stack)); // Leaves - stackable shulker boxes
     }
 
     default SlotAccess getChestVehicleSlot(final int index) {
diff --git a/net/minecraft/world/inventory/AbstractContainerMenu.java b/net/minecraft/world/inventory/AbstractContainerMenu.java
index 2a4763c951ddc78c9d8a39e661e59bbffc5cf109..8aa689129334f75986fb7a18895e2c3fb3c365c8 100644
--- a/net/minecraft/world/inventory/AbstractContainerMenu.java
+++ b/net/minecraft/world/inventory/AbstractContainerMenu.java
@@ -271,6 +271,13 @@ public abstract class AbstractContainerMenu {
         this.sendAllDataToRemote();
     }
 
+    // Leaves start - stackable shulker boxes
+    public void sendSingleSlot(int slotIndex, ItemStack item) {
+        if (this.synchronizer != null) {
+            this.synchronizer.sendSlotChange(this, slotIndex, item);
+        }
+    }
+    // Leaves end - stackable shulker boxes
     private void updateDataSlotListeners(int slotIndex, int value) {
         for (ContainerListener containerListener : this.containerListeners) {
             containerListener.dataChanged(this, slotIndex, value);
@@ -428,7 +435,7 @@ public abstract class AbstractContainerMenu {
                             && (this.quickcraftType == 2 || carried1.getCount() >= this.quickcraftSlots.size())
                             && this.canDragTo(slot1)) {
                             int i2 = slot1.hasItem() ? slot1.getItem().getCount() : 0;
-                            int min = Math.min(itemStack.getMaxStackSize(), slot1.getMaxStackSize(itemStack));
+                            int min = Math.min(org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(itemStack), slot1.getMaxStackSize(itemStack)); // Leaves - stackable shulker boxes
                             int min1 = Math.min(getQuickCraftPlaceCount(this.quickcraftSlots, this.quickcraftType, itemStack) + i2, min);
                             count -= min1 - i2;
                             // slot1.setByPlayer(itemStack.copyWithCount(min1));
@@ -542,7 +549,7 @@ public abstract class AbstractContainerMenu {
                                 slot.setByPlayer(carried2);
                             }
                         } else if (ItemStack.isSameItemSameComponents(carried, carried2)) {
-                            Optional<ItemStack> optional1 = slot.tryRemove(carried.getCount(), carried2.getMaxStackSize() - carried2.getCount(), player);
+                            Optional<ItemStack> optional1 = slot.tryRemove(carried.getCount(), org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(carried2) - carried2.getCount(), player); // Leaves - stackable shulker boxes
                             optional1.ifPresent(itemStack2 -> {
                                 carried2.grow(itemStack2.getCount());
                                 slot.onTake(player, itemStack2);
@@ -604,7 +611,7 @@ public abstract class AbstractContainerMenu {
             Slot slot2 = this.slots.get(slotId);
             if (slot2.hasItem()) {
                 ItemStack itemStack = slot2.getItem();
-                this.setCarried(itemStack.copyWithCount(itemStack.getMaxStackSize()));
+                this.setCarried(itemStack.copyWithCount(org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(itemStack))); // Leaves - stackable shulker boxes
             }
         } else if (clickType == ClickType.THROW && this.getCarried().isEmpty() && slotId >= 0) {
             Slot slot2 = this.slots.get(slotId);
@@ -635,15 +642,15 @@ public abstract class AbstractContainerMenu {
                 int maxStackSize = button == 0 ? 1 : -1;
 
                 for (int i3 = 0; i3 < 2; i3++) {
-                    for (int i4 = count; i4 >= 0 && i4 < this.slots.size() && itemStack.getCount() < itemStack.getMaxStackSize(); i4 += maxStackSize) {
+                    for (int i4 = count; i4 >= 0 && i4 < this.slots.size() && itemStack.getCount() < org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(itemStack); i4 += maxStackSize) { // Leaves - stackable shulker boxes
                         Slot slot3 = this.slots.get(i4);
                         if (slot3.hasItem()
                             && canItemQuickReplace(slot3, itemStack, true)
                             && slot3.mayPickup(player)
                             && this.canTakeItemForPickAll(itemStack, slot3)) {
                             ItemStack item1 = slot3.getItem();
-                            if (i3 != 0 || item1.getCount() != item1.getMaxStackSize()) {
-                                ItemStack itemStack1 = slot3.safeTake(item1.getCount(), itemStack.getMaxStackSize() - itemStack.getCount(), player);
+                            if (i3 != 0 || item1.getCount() != org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(item1)) { // Leaves - stackable shulker boxes
+                                ItemStack itemStack1 = slot3.safeTake(item1.getCount(), org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(itemStack) - itemStack.getCount(), player); // Leaves - stackable shulker boxes
                                 itemStack.grow(itemStack1.getCount());
                             }
                         }
@@ -761,7 +768,7 @@ public abstract class AbstractContainerMenu {
             i = endIndex - 1;
         }
 
-        if (stack.isStackable()) {
+        if (org.leavesmc.leaves.util.ShulkerBoxUtils.isStackable(stack)) { // Leaves - stackable shulker boxes
             while (!stack.isEmpty() && (reverseDirection ? i >= startIndex : i < endIndex)) {
                 Slot slot = this.slots.get(i);
                 ItemStack item = slot.getItem();
@@ -862,7 +869,7 @@ public abstract class AbstractContainerMenu {
     public static boolean canItemQuickReplace(@Nullable Slot slot, ItemStack stack, boolean stackSizeMatters) {
         boolean flag = slot == null || !slot.hasItem();
         return !flag && ItemStack.isSameItemSameComponents(stack, slot.getItem())
-            ? slot.getItem().getCount() + (stackSizeMatters ? 0 : stack.getCount()) <= stack.getMaxStackSize()
+            ? slot.getItem().getCount() + (stackSizeMatters ? 0 : stack.getCount()) <= org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(stack) // Leaves - stackable shulker boxes
             : flag;
     }
 
@@ -870,7 +877,7 @@ public abstract class AbstractContainerMenu {
         return switch (type) {
             case 0 -> Mth.floor((float)stack.getCount() / slots.size());
             case 1 -> 1;
-            case 2 -> stack.getMaxStackSize();
+            case 2 -> org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(stack); // Leaves - stackable shulker boxes
             default -> stack.getCount();
         };
     }
@@ -892,7 +899,7 @@ public abstract class AbstractContainerMenu {
             for (int i = 0; i < container.getContainerSize(); i++) {
                 ItemStack item = container.getItem(i);
                 if (!item.isEmpty()) {
-                    f += (float)item.getCount() / container.getMaxStackSize(item);
+                    f += (float)item.getCount() / container.getMaxStackLeaves(item); // Leaves - stackable shulker boxes
                 }
             }
 
diff --git a/net/minecraft/world/inventory/MerchantContainer.java b/net/minecraft/world/inventory/MerchantContainer.java
index 1e5dfb1f9e371fa23cdfa9280797aa0e183d4cd2..cf87267130c0aebd38206556261929d6f6383bc9 100644
--- a/net/minecraft/world/inventory/MerchantContainer.java
+++ b/net/minecraft/world/inventory/MerchantContainer.java
@@ -109,7 +109,7 @@ public class MerchantContainer implements Container {
     @Override
     public void setItem(int index, ItemStack stack) {
         this.itemStacks.set(index, stack);
-        stack.limitSize(this.getMaxStackSize(stack));
+        stack.limitSize(this.getMaxStackLeaves(stack)); // Leaves - stackable shulker boxes
         if (this.isPaymentSlot(index)) {
             this.updateSellItem();
         }
diff --git a/net/minecraft/world/inventory/Slot.java b/net/minecraft/world/inventory/Slot.java
index 5ceb8964476b40db4511bec91ff13c4f522a1357..371bad86218971d6e031c6d74307b2ab0d460997 100644
--- a/net/minecraft/world/inventory/Slot.java
+++ b/net/minecraft/world/inventory/Slot.java
@@ -75,7 +75,7 @@ public class Slot {
     }
 
     public int getMaxStackSize(ItemStack stack) {
-        return Math.min(this.getMaxStackSize(), stack.getMaxStackSize());
+        return Math.min(this.getMaxStackSize(), org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(stack)); // Leaves - stackable shulker boxes
     }
 
     @Nullable
diff --git a/net/minecraft/world/item/ItemStack.java b/net/minecraft/world/item/ItemStack.java
index 24ecca78dc1140b6fc47d59f2acefca6bc2b0220..649d17dcd7856e3b1344192d8ea4b2e9f73fc03b 100644
--- a/net/minecraft/world/item/ItemStack.java
+++ b/net/minecraft/world/item/ItemStack.java
@@ -165,7 +165,7 @@ public final class ItemStack implements DataComponentHolder {
     @Deprecated
     @Nullable
     private Item item;
-    PatchedDataComponentMap components;
+    public PatchedDataComponentMap components; // Leaves - stackable shulker boxes
     @Nullable
     private Entity entityRepresentation;
 
@@ -192,7 +192,8 @@ public final class ItemStack implements DataComponentHolder {
                 } else {
                     Holder<Item> holder = Item.STREAM_CODEC.decode(buffer);
                     DataComponentPatch dataComponentPatch = codec.decode(buffer);
-                    return new ItemStack(holder, varInt, dataComponentPatch);
+                    ItemStack itemStack = new ItemStack(holder, varInt, dataComponentPatch);
+                    return org.leavesmc.leaves.util.ShulkerBoxUtils.decodeMaxStackSize(itemStack);
                 }
             }
 
@@ -201,13 +202,15 @@ public final class ItemStack implements DataComponentHolder {
                 if (value.isEmpty() || value.getItem() == null) { // CraftBukkit - NPE fix itemstack.getItem()
                     buffer.writeVarInt(0);
                 } else {
-                    buffer.writeVarInt(io.papermc.paper.util.sanitizer.ItemComponentSanitizer.sanitizeCount(io.papermc.paper.util.sanitizer.ItemObfuscationSession.currentSession(), value, value.getCount())); // Paper - potentially sanitize count
-                    Item.STREAM_CODEC.encode(buffer, value.getItemHolder());
+                    // Leaves start - stackable shulker boxes
+                    final ItemStack itemStack = org.leavesmc.leaves.util.ShulkerBoxUtils.encodeMaxStackSize(value.copy());
+                    buffer.writeVarInt(io.papermc.paper.util.sanitizer.ItemComponentSanitizer.sanitizeCount(io.papermc.paper.util.sanitizer.ItemObfuscationSession.currentSession(), itemStack, itemStack.getCount())); // Paper - potentially sanitize count
+                    Item.STREAM_CODEC.encode(buffer, itemStack.getItemHolder());
                     // Paper start - adventure; conditionally render translatable components
                     boolean prev = net.minecraft.network.chat.ComponentSerialization.DONT_RENDER_TRANSLATABLES.get();
-                    try (final io.papermc.paper.util.SafeAutoClosable ignored = io.papermc.paper.util.sanitizer.ItemObfuscationSession.withContext(c -> c.itemStack(value))) { // pass the itemstack as context to the obfuscation session
+                    try (final io.papermc.paper.util.SafeAutoClosable ignored = io.papermc.paper.util.sanitizer.ItemObfuscationSession.withContext(c -> c.itemStack(itemStack))) { // pass the itemstack as context to the obfuscation session
                         net.minecraft.network.chat.ComponentSerialization.DONT_RENDER_TRANSLATABLES.set(true);
-                    codec.encode(buffer, value.components.asPatch());
+                    codec.encode(buffer, itemStack.components.asPatch());
                     } finally {
                         net.minecraft.network.chat.ComponentSerialization.DONT_RENDER_TRANSLATABLES.set(prev);
                     }
@@ -302,7 +305,7 @@ public final class ItemStack implements DataComponentHolder {
 
             for (ItemStack itemStack : itemContainerContents.nonEmptyItems()) {
                 int count = itemStack.getCount();
-                int maxStackSize = itemStack.getMaxStackSize();
+                int maxStackSize = org.leavesmc.leaves.util.ShulkerBoxUtils.getItemStackMaxCount(itemStack); // Leaves - stackable shulker boxes
                 if (count > maxStackSize) {
                     return DataResult.error(() -> "Item stack with count of " + count + " was larger than maximum: " + maxStackSize);
                 }
diff --git a/net/minecraft/world/level/block/AbstractCauldronBlock.java b/net/minecraft/world/level/block/AbstractCauldronBlock.java
index ad3f32888afd8b5f0038445a1b0fcc8cacec9fe2..18b7b7fe68c54a400f269f5ff1d09fe9e3d519b8 100644
--- a/net/minecraft/world/level/block/AbstractCauldronBlock.java
+++ b/net/minecraft/world/level/block/AbstractCauldronBlock.java
@@ -62,9 +62,27 @@ public abstract class AbstractCauldronBlock extends Block {
         ItemStack stack, BlockState state, Level level, BlockPos pos, Player player, InteractionHand hand, BlockHitResult hitResult
     ) {
         CauldronInteraction cauldronInteraction = this.interactions.map().get(stack.getItem());
-        return cauldronInteraction.interact(state, level, pos, player, hand, stack, hitResult.getDirection()); // Paper - pass hit direction
+        return wrapInteractor(cauldronInteraction, state, level, pos, player, hand, stack, hitResult.getDirection()); // Paper - pass hit direction // Leaves - stackable shulker boxes
     }
 
+    // Leaves start - stackable shulker boxes
+    private InteractionResult wrapInteractor(CauldronInteraction cauldronBehavior, BlockState blockState, Level world, BlockPos blockPos, Player playerEntity, InteractionHand hand, ItemStack itemStack, net.minecraft.core.Direction hitDirection) {
+        int count = -1;
+        if (org.leavesmc.leaves.LeavesConfig.modify.shulkerBoxStackSize > 1 && itemStack.getItem() instanceof net.minecraft.world.item.BlockItem bi &&
+            bi.getBlock() instanceof ShulkerBoxBlock) {
+            count = itemStack.getCount();
+        }
+        InteractionResult result = cauldronBehavior.interact(blockState, world, blockPos, playerEntity, hand, itemStack, hitDirection);
+        if (count > 0 && result.consumesAction()) {
+            ItemStack current = playerEntity.getItemInHand(hand);
+            if (current.getItem() instanceof net.minecraft.world.item.BlockItem bi && bi.getBlock() instanceof ShulkerBoxBlock) {
+                current.setCount(count);
+            }
+        }
+        return result;
+    }
+    // Leaves end - stackable shulker boxes
+
     @Override
     protected VoxelShape getShape(BlockState state, BlockGetter level, BlockPos pos, CollisionContext context) {
         return SHAPE;
diff --git a/net/minecraft/world/level/block/CrafterBlock.java b/net/minecraft/world/level/block/CrafterBlock.java
index 38b03c7b02bdfc579e5e126c12de3d878e26d188..33e24f2c3b63b2d3b55dfae2f2e55869abeed055 100644
--- a/net/minecraft/world/level/block/CrafterBlock.java
+++ b/net/minecraft/world/level/block/CrafterBlock.java
@@ -192,7 +192,7 @@ public class CrafterBlock extends BaseEntityBlock {
         Direction direction = state.getValue(ORIENTATION).front();
         Container containerAt = HopperBlockEntity.getContainerAt(level, pos.relative(direction));
         ItemStack itemStack = stack.copy();
-        if (containerAt != null && (containerAt instanceof CrafterBlockEntity || stack.getCount() > containerAt.getMaxStackSize(stack))) {
+        if (containerAt != null && (containerAt instanceof CrafterBlockEntity || stack.getCount() > containerAt.getMaxStackLeaves(stack))) { // Leaves - stackable shulker boxes
             // CraftBukkit start - InventoryMoveItemEvent
             org.bukkit.craftbukkit.inventory.CraftItemStack oitemstack = org.bukkit.craftbukkit.inventory.CraftItemStack.asCraftMirror(itemStack);
 
diff --git a/net/minecraft/world/level/block/entity/AbstractFurnaceBlockEntity.java b/net/minecraft/world/level/block/entity/AbstractFurnaceBlockEntity.java
index 7729c33cad94cf2b4162324be75713650fc9d378..78b3bdb668320e9cf2fb09b59929fac43cf56aca 100644
--- a/net/minecraft/world/level/block/entity/AbstractFurnaceBlockEntity.java
+++ b/net/minecraft/world/level/block/entity/AbstractFurnaceBlockEntity.java
@@ -409,7 +409,7 @@ public abstract class AbstractFurnaceBlockEntity extends BaseContainerBlockEntit
         ItemStack itemStack = this.items.get(index);
         boolean flag = !stack.isEmpty() && ItemStack.isSameItemSameComponents(itemStack, stack);
         this.items.set(index, stack);
-        stack.limitSize(this.getMaxStackSize(stack));
+        stack.limitSize(this.getMaxStackLeaves(stack)); // Leaves - stackable shulker boxes
         if (index == 0 && !flag && this.level instanceof ServerLevel serverLevel) {
             this.cookingTotalTime = getTotalCookTime(serverLevel, this, this.recipeType, this.cookSpeedMultiplier); // Paper - cook speed multiplier API
             this.cookingTimer = 0;
diff --git a/net/minecraft/world/level/block/entity/BaseContainerBlockEntity.java b/net/minecraft/world/level/block/entity/BaseContainerBlockEntity.java
index c63370fd458fb4f7190b79b1a8174fcc92d88f9c..4cca3fbbb93bb76d5d501dfad6997d909211809e 100644
--- a/net/minecraft/world/level/block/entity/BaseContainerBlockEntity.java
+++ b/net/minecraft/world/level/block/entity/BaseContainerBlockEntity.java
@@ -148,7 +148,7 @@ public abstract class BaseContainerBlockEntity extends BlockEntity implements Co
     @Override
     public void setItem(int slot, ItemStack stack) {
         this.getItems().set(slot, stack);
-        stack.limitSize(this.getMaxStackSize(stack));
+        stack.limitSize(this.getMaxStackLeaves(stack)); // Leaves - stackable shulker boxes
         this.setChanged();
     }
 
diff --git a/net/minecraft/world/level/block/entity/HopperBlockEntity.java b/net/minecraft/world/level/block/entity/HopperBlockEntity.java
index 2d979850378c05ce569782d8e04a452f986612a7..a2fe5fdf50ae731e423821a0d1c52141b478e0be 100644
--- a/net/minecraft/world/level/block/entity/HopperBlockEntity.java
+++ b/net/minecraft/world/level/block/entity/HopperBlockEntity.java
@@ -113,7 +113,7 @@ public class HopperBlockEntity extends RandomizableContainerBlockEntity implemen
     public void setItem(int index, ItemStack stack) {
         this.unpackLootTable(null);
         this.getItems().set(index, stack);
-        stack.limitSize(this.getMaxStackSize(stack));
+        stack.limitSize(this.getMaxStackLeaves(stack)); // Leaves - stackable shulker boxes
     }
 
     @Override
@@ -692,9 +692,9 @@ public class HopperBlockEntity extends RandomizableContainerBlockEntity implemen
             if (item.isEmpty()) {
                 // Spigot start - SPIGOT-6693, SimpleContainer#setItem
                 ItemStack leftover = ItemStack.EMPTY; // Paper - Make hoppers respect inventory max stack size
-                if (!stack.isEmpty() && stack.getCount() > destination.getMaxStackSize()) {
+                if (!stack.isEmpty() && (stack.getCount() > destination.getMaxStackSize() || stack.getCount() > stack.getMaxStackSize())) { // Leaves - stackable shulker boxes
                     leftover = stack; // Paper - Make hoppers respect inventory max stack size
-                    stack = stack.split(destination.getMaxStackSize());
+                    stack = stack.split(Math.min(destination.getMaxStackSize(), stack.getMaxStackSize())); // Leaves - stackable shulker boxes
                 }
                 // Spigot end
                 ignoreBlockEntityUpdates = true; // Paper - Perf: Optimize Hoppers