From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Thu, 8 Oct 2020 00:00:25 -0400
Subject: [PATCH] Fix "Not a string" Map Conversion spam

The maps did convert successfully, but had noisy logs due to Spigot
implementing this logic incorrectly.

This stops the spam by converting the old format to new before
requesting the world.

Track spigot issue to see when fixed: https://hub.spigotmc.org/jira/browse/SPIGOT-6181

diff --git a/src/main/java/net/minecraft/world/level/saveddata/maps/MapItemSavedData.java b/src/main/java/net/minecraft/world/level/saveddata/maps/MapItemSavedData.java
index e1623ade449fe56ec51955ee9594a93f85660c51..5992f450f01349ce49286c34b8af56737de01a45 100644
--- a/src/main/java/net/minecraft/world/level/saveddata/maps/MapItemSavedData.java
+++ b/src/main/java/net/minecraft/world/level/saveddata/maps/MapItemSavedData.java
@@ -15,6 +15,8 @@ import net.minecraft.core.BlockPos;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.nbt.ListTag;
 import net.minecraft.nbt.NbtOps;
+import net.minecraft.nbt.NumericTag;
+import net.minecraft.nbt.StringTag;
 import net.minecraft.nbt.Tag;
 import net.minecraft.network.chat.Component;
 import net.minecraft.network.protocol.Packet;
@@ -110,7 +112,26 @@ public class MapItemSavedData extends SavedData {
     }
 
     public static MapItemSavedData load(CompoundTag nbt) {
-        DataResult<ResourceKey<Level>> dataresult = DimensionType.parseLegacy(new Dynamic(NbtOps.INSTANCE, nbt.get("dimension"))); // CraftBukkit - decompile error
+        // Paper start - fix "Not a string" spam
+        Tag dimension = nbt.get("dimension");
+        if (dimension instanceof NumericTag && ((NumericTag) dimension).getAsInt() >= CraftWorld.CUSTOM_DIMENSION_OFFSET) {
+            long least = nbt.getLong("UUIDLeast");
+            long most = nbt.getLong("UUIDMost");
+
+            if (least != 0L && most != 0L) {
+                UUID uuid = new UUID(most, least);
+                CraftWorld world = (CraftWorld) Bukkit.getWorld(uuid);
+                if (world != null) {
+                    dimension = StringTag.valueOf("minecraft:" + world.getName().toLowerCase(java.util.Locale.ENGLISH));
+                } else {
+                    dimension = StringTag.valueOf("bukkit:_invalidworld_");
+                }
+            } else {
+                dimension = StringTag.valueOf("bukkit:_invalidworld_");
+            }
+        }
+        DataResult<ResourceKey<Level>> dataresult = DimensionType.parseLegacy(new Dynamic(NbtOps.INSTANCE, dimension)); // CraftBukkit - decompile error
+        // Paper end - fix "Not a string" spam
         Logger logger = MapItemSavedData.LOGGER;
 
         Objects.requireNonNull(logger);