Paper/patches/server/0227-Don-t-call-getItemMeta-on-hasItemMeta.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Hugo Manrique <hugmanrique@gmail.com>
Date: Thu, 26 Jul 2018 14:10:23 +0200
Subject: [PATCH] Don't call getItemMeta on hasItemMeta

Spigot 1.13 checks if any field (which are manually copied from the ItemStack's "tag" NBT tag) on the ItemMeta class of an ItemStack is set.

We could just check if the "tag" NBT tag is empty, albeit that would break some plugins. The only general tag added on 1.13 is "Damage", and we can just check if the "tag" NBT tag contains any other tag that's not "Damage" (https://minecraft.wiki/wiki/Player.dat_format#Item_structure) making the `hasItemStack` method behave as before.

Returns true if getDamage() == 0 or has damage tag or other tag is set.
Check the `ItemMetaTest#testTaggedButNotMeta` method to see how this method behaves.

diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java
index a58e865a047550cc4508d0515cc6f2fc639f9b3d..13e6fc9f42d63fdbd659462070dc7f0767fbb1d9 100644
--- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java
+++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java
@@ -681,7 +681,7 @@ public final class CraftItemStack extends ItemStack {
 
     @Override
     public boolean hasItemMeta() {
-        return CraftItemStack.hasItemMeta(this.handle) && !CraftItemFactory.instance().equals(this.getItemMeta(), null);
+        return CraftItemStack.hasItemMeta(this.handle) && (this.handle.getDamageValue() != 0 || (this.handle.getTag() != null && this.handle.getTag().tags.size() >= (this.handle.getTag().contains(CraftMetaItem.DAMAGE.NBT) ? 2 : 1))); // Paper - keep 1.12 CraftBukkit behavior without calling getItemMeta
     }
 
     static boolean hasItemMeta(net.minecraft.world.item.ItemStack item) {
diff --git a/src/test/java/org/bukkit/craftbukkit/inventory/ItemMetaTest.java b/src/test/java/org/bukkit/craftbukkit/inventory/ItemMetaTest.java
index cf436c9e62a11b8c6cbf7638de0e5635c67459ac..7237e24686885c754c87e7eec53c6400fd0b47bf 100644
--- a/src/test/java/org/bukkit/craftbukkit/inventory/ItemMetaTest.java
+++ b/src/test/java/org/bukkit/craftbukkit/inventory/ItemMetaTest.java
@@ -106,6 +106,34 @@ public class ItemMetaTest extends AbstractTestingBase {
         assertThat(itemMeta.hasConflictingEnchant(null), is(false));
     }
 
+    // Paper start
+    private void testItemMeta(ItemStack stack) {
+        assertThat(stack.hasItemMeta(), is(false), "Should not have ItemMeta");
+
+        stack.setDurability((short) 0);
+        assertThat(stack.hasItemMeta(), is(false), "ItemStack with zero durability should not have ItemMeta");
+
+        stack.setDurability((short) 2);
+        assertThat(stack.hasItemMeta(), is(true), "ItemStack with non-zero durability should have ItemMeta");
+
+        stack.setLore(java.util.Collections.singletonList("Lore"));
+        assertThat(stack.hasItemMeta(), is(true), "ItemStack with lore and durability should have ItemMeta");
+
+        stack.setDurability((short) 0);
+        assertThat(stack.hasItemMeta(), is(true), "ItemStack with lore should have ItemMeta");
+
+        stack.setLore(null);
+    }
+
+    @Test
+    public void testHasItemMeta() {
+        ItemStack itemStack = new ItemStack(Material.SHEARS);
+
+        testItemMeta(itemStack);
+        testItemMeta(CraftItemStack.asCraftCopy(itemStack));
+    }
+    // Paper end
+
     @Test
     public void testConflictingStoredEnchantment() {
         EnchantmentStorageMeta itemMeta = (EnchantmentStorageMeta) Bukkit.getItemFactory().getItemMeta(Material.ENCHANTED_BOOK);