PaperMC/Spigot-Server-Patches/0307-Don-t-call-getItemMeta-on-hasItemMeta.patch

From 6f951c08506ab811908bc19c17634c2f8c4ce97a 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 1282ee399..f41ccba79 100644
--- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java
+++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java
@@ -524,7 +524,7 @@ public final class CraftItemStack extends ItemStack {
 
     @Override
     public boolean hasItemMeta() {
-        return hasItemMeta(handle) && !CraftItemFactory.instance().equals(getItemMeta(), null);
+        return hasItemMeta(handle) && (handle.getDamage() != 0 || (handle.getTag() != null && handle.getTag().map.size() >= (handle.getTag().hasKey(CraftMetaItem.DAMAGE.NBT) ? 2 : 1))); // Paper - keep 1.12 CraftBukkit behavior without calling getItemMeta
     }
 
     static boolean hasItemMeta(net.minecraft.server.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 0ad0004b9..7455461f1 100644
--- a/src/test/java/org/bukkit/craftbukkit/inventory/ItemMetaTest.java
+++ b/src/test/java/org/bukkit/craftbukkit/inventory/ItemMetaTest.java
@@ -5,6 +5,7 @@ import static org.hamcrest.Matchers.*;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections; // Paper
 import java.util.List;
 import java.util.UUID;
 
@@ -159,8 +160,47 @@ public class ItemMetaTest extends AbstractTestingBase {
         ItemStack pureBukkit = new ItemStack(Material.SHEARS);
         assertThat("Bukkit and craft stacks should be similar", craft.isSimilar(pureBukkit), is(true));
         assertThat("Bukkit and craft stacks should be equal", craft.equals(pureBukkit), is(true));
+        // Paper start - test additional ItemMeta damage cases
+        ItemStack clone = CraftItemStack.asBukkitCopy(CraftItemStack.asNMSCopy(craft));
+        assertThat("Bukkit and craft stacks should be similar", craft.isSimilar(clone), is(true));
+        assertThat("Bukkit and craft stacks should be equal", craft.equals(clone), is(true));
+
+        pureBukkit = new ItemStack(Material.DIAMOND_SWORD);
+        pureBukkit.setDurability((short) 2);
+        net.minecraft.server.ItemStack nms = CraftItemStack.asNMSCopy(pureBukkit);
+        ItemStack other = CraftItemStack.asBukkitCopy(nms);
+
+        assertThat("Bukkit and NMS ItemStack copies should be similar", pureBukkit.isSimilar(other), is(true));
+        assertThat("Bukkit and NMS ItemStack copies should be equal", pureBukkit.equals(other), is(true));
     }
 
+    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(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 testBlockStateMeta() {
         List<Block> queue = new ArrayList<>();
-- 
2.20.1