PaperMC/patches/server/0231-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.gamepedia.com/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 846c89f7502b6f9a288b2fb7b6a7ba55b6fe1a38..7f6d331cf832f57857519b6e9801c3b45b53fc32 100644
--- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java
+++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java
@@ -622,7 +622,7 @@ 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 13144f8d1dc0a2ca640d138e6c7930c1736ec4a0..5239cc38e02051d662518f103534d44e3d22d6b9 100644
--- a/src/test/java/org/bukkit/craftbukkit/inventory/ItemMetaTest.java
+++ b/src/test/java/org/bukkit/craftbukkit/inventory/ItemMetaTest.java
@@ -99,6 +99,34 @@ public class ItemMetaTest extends AbstractTestingBase {
         assertThat(itemMeta.hasConflictingEnchant(null), is(false));
     }
 
+    // Paper start
+    private void testItemMeta(ItemStack stack) {
+        assertThat("Should not have ItemMeta", stack.hasItemMeta(), is(false));
+
+        stack.setDurability((short) 0);
+        assertThat("ItemStack with zero durability should not have ItemMeta", stack.hasItemMeta(), is(false));
+
+        stack.setDurability((short) 2);
+        assertThat("ItemStack with non-zero durability should have ItemMeta", stack.hasItemMeta(), is(true));
+
+        stack.setLore(java.util.Collections.singletonList("Lore"));
+        assertThat("ItemStack with lore and durability should have ItemMeta", stack.hasItemMeta(), is(true));
+
+        stack.setDurability((short) 0);
+        assertThat("ItemStack with lore should have ItemMeta", stack.hasItemMeta(), is(true));
+
+        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);