Auto sort enchants on items - Fixes #915

This ensures that enchants are never added in inconsistent order.
The client shows the enchants in a sorted order already

This will auto fix previously created items too on load.

Spigot-Server-Patches/Fix-NFE-when-attempting-to-read-EMPTY-ItemStack.patch

@@ -6,7 +6,7 @@ Subject: [PATCH] Fix NFE when attempting to read EMPTY ItemStack
 Thanks @gabizou
 
 diff --git a/src/main/java/net/minecraft/server/ItemStack.java b/src/main/java/net/minecraft/server/ItemStack.java
-index 3aefb023e..8c7f57bc7 100644
+index 9465f4c16..52cb34abd 100644
 --- a/src/main/java/net/minecraft/server/ItemStack.java
 +++ b/src/main/java/net/minecraft/server/ItemStack.java
 @@ -0,0 +0,0 @@ public final class ItemStack {

Spigot-Server-Patches/Handle-Item-Meta-Inconsistencies.patch

@@ -17,8 +17,76 @@ was added, resulting in 2 different ways to modify an items enchantments.
 For consistency, the old API methods now forward to use the
 ItemMeta API equivalents, and should deprecate the old API's.
 
+diff --git a/src/main/java/net/minecraft/server/ItemStack.java b/src/main/java/net/minecraft/server/ItemStack.java
+index 0dcea61d2..a8f7ff98f 100644
+--- a/src/main/java/net/minecraft/server/ItemStack.java
++++ b/src/main/java/net/minecraft/server/ItemStack.java
+@@ -0,0 +0,0 @@ public final class ItemStack {
+     }
+ 
+     // CraftBukkit start
++    // Paper start
++    private static final java.util.Comparator<NBTTagCompound> enchantSorter = java.util.Comparator.comparingInt(o -> o.getShort("id"));
++    private void processEnchantOrder(NBTTagCompound tag) {
++        if (tag == null || !tag.hasKeyOfType("ench", 9)) {
++            return;
++        }
++        NBTTagList list = tag.getList("ench", 10);
++        if (list.size() < 2) {
++            return;
++        }
++        try {
++            list.sort(enchantSorter); // Paper
++        } catch (Exception ignored) {}
++    }
++    // Paper end
++
+     public ItemStack(Item item, int i, int j) {
+         this(item, i, j, true);
+     }
+@@ -0,0 +0,0 @@ public final class ItemStack {
+         if (nbttagcompound.hasKeyOfType("tag", 10)) {
+             // CraftBukkit start - make defensive copy as this data may be coming from the save thread
+             this.tag = (NBTTagCompound) nbttagcompound.getCompound("tag").clone();
++            processEnchantOrder(this.tag); // Paper
+             if (this.item != null) {
+                 this.item.a(this.tag);
+                 // CraftBukkit end
+@@ -0,0 +0,0 @@ public final class ItemStack {
+ 
+     public void setTag(@Nullable NBTTagCompound nbttagcompound) {
+         this.tag = nbttagcompound;
++        processEnchantOrder(this.tag); // Paper
+     }
+ 
+     public String getName() {
+@@ -0,0 +0,0 @@ public final class ItemStack {
+         nbttagcompound.setShort("id", (short) Enchantment.getId(enchantment));
+         nbttagcompound.setShort("lvl", (short) ((byte) i));
+         nbttaglist.add(nbttagcompound);
++        processEnchantOrder(nbttagcompound); // Paper
+     }
+ 
+     public boolean hasEnchantments() {
+diff --git a/src/main/java/net/minecraft/server/NBTTagList.java b/src/main/java/net/minecraft/server/NBTTagList.java
+index ca9eb2f3b..576c3b714 100644
+--- a/src/main/java/net/minecraft/server/NBTTagList.java
++++ b/src/main/java/net/minecraft/server/NBTTagList.java
+@@ -0,0 +0,0 @@ public class NBTTagList extends NBTBase {
+ 
+     private static final Logger b = LogManager.getLogger();
+     public List<NBTBase> list = Lists.newArrayList(); // Paper
++    // Paper start
++    public void sort(java.util.Comparator<? extends NBTBase> comparator) {
++        //noinspection unchecked
++        java.util.Collections.sort(list, (java.util.Comparator<NBTBase>) comparator);
++    }
++    // Paper end
+     private byte type = 0;
+ 
+     public NBTTagList() {}
 diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java
-index 3f11e427..ebb3e04b 100644
+index fb1dc542d..cdf16e15a 100644
 --- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java
 +++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java
 @@ -0,0 +0,0 @@ import static org.bukkit.craftbukkit.inventory.CraftMetaItem.ENCHANTMENTS;
@@ -144,7 +212,7 @@ index 3f11e427..ebb3e04b 100644
  
      static Map<Enchantment, Integer> getEnchantments(net.minecraft.server.ItemStack item) {
 diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java
-index c743ae06..0cdc8007 100644
+index c743ae066..0cdc8007a 100644
 --- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java
 +++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java
 @@ -0,0 +0,0 @@ import java.lang.annotation.RetentionPolicy;

Spigot-Server-Patches/Optimize-ItemStack.isEmpty.patch

@@ -6,7 +6,7 @@ Subject: [PATCH] Optimize ItemStack.isEmpty()
 Remove hashMap lookup every check, simplify code to remove ternary
 
 diff --git a/src/main/java/net/minecraft/server/ItemStack.java b/src/main/java/net/minecraft/server/ItemStack.java
-index 0dcea61d2..3aefb023e 100644
+index a8f7ff98f..9465f4c16 100644
 --- a/src/main/java/net/minecraft/server/ItemStack.java
 +++ b/src/main/java/net/minecraft/server/ItemStack.java
 @@ -0,0 +0,0 @@ public final class ItemStack {