From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Owen1212055 <23108066+Owen1212055@users.noreply.github.com>
Date: Wed, 20 Mar 2024 20:41:35 -0400
Subject: [PATCH] Item Mutation Fixes


diff --git a/src/main/java/net/minecraft/world/inventory/EnchantmentMenu.java b/src/main/java/net/minecraft/world/inventory/EnchantmentMenu.java
index 343f44db579839eb61376f876b5eff2e615dc2e5..e6935b6632c7a7e07f4da459c95f564356242f98 100644
--- a/src/main/java/net/minecraft/world/inventory/EnchantmentMenu.java
+++ b/src/main/java/net/minecraft/world/inventory/EnchantmentMenu.java
@@ -229,7 +229,7 @@ public class EnchantmentMenu extends AbstractContainerMenu {
                 return false;
             } else if (this.costs[id] > 0 && !itemstack.isEmpty() && (player.experienceLevel >= j && player.experienceLevel >= this.costs[id] || player.getAbilities().instabuild)) {
                 this.access.execute((world, blockposition) -> {
-                    ItemStack itemstack2 = itemstack;
+                    ItemStack itemstack2 = itemstack; // Paper - diff on change
                     List<EnchantmentInstance> list = this.getEnchantmentList(itemstack, id, this.costs[id]);
 
                     // CraftBukkit start
@@ -251,11 +251,18 @@ public class EnchantmentMenu extends AbstractContainerMenu {
                             return;
                         }
                         // CraftBukkit end
-                        boolean flag = itemstack.is(Items.BOOK);
+                        // Paper start
+                        itemstack2 = org.bukkit.craftbukkit.inventory.CraftItemStack.getOrCloneOnMutation(item, event.getItem());
+                        if (itemstack2 != itemstack) {
+                            this.enchantSlots.setItem(0, itemstack2);
+                        }
+                        boolean flag = itemstack2.is(Items.BOOK);
+                        // Paper end
 
                         if (flag) {
+                            CompoundTag nbttagcompound = itemstack2.getTag(); // Paper - move up
                             itemstack2 = new ItemStack(Items.ENCHANTED_BOOK);
-                            CompoundTag nbttagcompound = itemstack.getTag();
+                            // Paper - move up
 
                             if (nbttagcompound != null) {
                                 itemstack2.setTag(nbttagcompound.copy());
@@ -277,7 +284,7 @@ public class EnchantmentMenu extends AbstractContainerMenu {
                                     EnchantmentInstance weightedrandomenchant = new EnchantmentInstance(nms, entry.getValue());
                                     EnchantedBookItem.addEnchantment(itemstack2, weightedrandomenchant);
                                 } else {
-                                    item.addUnsafeEnchantment(entry.getKey(), entry.getValue());
+                                    CraftItemStack.asCraftMirror(itemstack2).addUnsafeEnchantment(entry.getKey(), entry.getValue()); // Paper
                                 }
                             } catch (IllegalArgumentException e) {
                                 /* Just swallow invalid enchantments */