From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Taiyou06 <kaandindar21@gmail.com>
Date: Fri, 7 Feb 2025 21:41:51 +0100
Subject: [PATCH] Cache ItemStack max stack size

Abandoned plan, maybe research deeper in this part in the future, maybe not

diff --git a/net/minecraft/world/item/ItemStack.java b/net/minecraft/world/item/ItemStack.java
index fd7c1e800cbd4919a1a47f6c468c8776535bd028..fdd7e89bacc98e23f067ba17d0bd93ee84a388cb 100644
--- a/net/minecraft/world/item/ItemStack.java
+++ b/net/minecraft/world/item/ItemStack.java
@@ -194,6 +194,7 @@ public final class ItemStack implements DataComponentHolder, net.caffeinemc.mods
     private static final Logger LOGGER = LogUtils.getLogger();
     public static final ItemStack EMPTY = new ItemStack((Void)null);
     private static final Component DISABLED_ITEM_TOOLTIP = Component.translatable("item.disabled").withStyle(ChatFormatting.RED);
+    private int maxStackSize;
     private int count;
     private int popTime;
     @Deprecated
@@ -289,11 +290,13 @@ public final class ItemStack implements DataComponentHolder, net.caffeinemc.mods
         this.count = count;
         this.components = components;
         this.getItem().verifyComponentsAfterLoad(this);
+        this.maxStackSize = getMaxStackSizeInternal(); // Leaf - Cache ItemStack max stack size
     }
 
     private ItemStack(@Nullable Void unused) {
         this.item = null;
         this.components = new PatchedDataComponentMap(DataComponentMap.EMPTY);
+        this.maxStackSize = 1; // Leaf - Cache ItemStack max stack size - taken from ItemStack#isEmpty
     }
 
     public static DataResult<Unit> validateComponents(DataComponentMap components) {
@@ -619,9 +622,15 @@ public final class ItemStack implements DataComponentHolder, net.caffeinemc.mods
     }
 
     public int getMaxStackSize() {
-        return this.getOrDefault(DataComponents.MAX_STACK_SIZE, Integer.valueOf(1));
+        return maxStackSize; // Leaf - Cache ItemStack max stack size
     }
 
+    // Leaf start - Cache ItemStack max stack size
+    private int getMaxStackSizeInternal() {
+        return this.getOrDefault(DataComponents.MAX_STACK_SIZE, 1);
+    }
+    // Leaf end - Cache ItemStack max stack size
+
     public boolean isStackable() {
         return this.getMaxStackSize() > 1 && (!this.isDamageableItem() || !this.isDamaged());
     }
@@ -1339,6 +1348,7 @@ public final class ItemStack implements DataComponentHolder, net.caffeinemc.mods
         this.components = new PatchedDataComponentMap(this.item.components());
         this.applyComponents(patch);
         // Paper end - change base component prototype
+        this.maxStackSize = getMaxStackSizeInternal(); // Leaf - Cache ItemStack max stack size
     }
     // CraftBukkit end
 
@@ -1396,6 +1406,7 @@ public final class ItemStack implements DataComponentHolder, net.caffeinemc.mods
         }
         // Leaf end - Lithium - equipment tracking
         this.count = count;
+        maxStackSize = count <= 0 ? 1 : getMaxStackSizeInternal(); // Leaf - Cache ItemStack max stack size - taken from ItemStack#isEmpty
     }
 
     public void limitSize(int maxSize) {