From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Tue, 26 Sep 2023 18:32:49 -0700
Subject: [PATCH] Fix creating the reverse map for loot table keys


diff --git a/src/main/java/net/minecraft/world/level/storage/loot/LootDataManager.java b/src/main/java/net/minecraft/world/level/storage/loot/LootDataManager.java
index dd375fffa727db76fa989248b9b836960974c372..3563fdb8f8d3dbaabc611ab5cdba1d771406b336 100644
--- a/src/main/java/net/minecraft/world/level/storage/loot/LootDataManager.java
+++ b/src/main/java/net/minecraft/world/level/storage/loot/LootDataManager.java
@@ -30,7 +30,7 @@ public class LootDataManager implements PreparableReloadListener, LootDataResolv
     public static final LootDataId<LootTable> EMPTY_LOOT_TABLE_KEY = new LootDataId<>(LootDataType.TABLE, BuiltInLootTables.EMPTY);
     private Map<LootDataId<?>, ?> elements = Map.of();
     private Multimap<LootDataType<?>, ResourceLocation> typeKeys = ImmutableMultimap.of();
-    public Map<?, ResourceLocation> lootTableToKey = ImmutableMap.of(); // CraftBukkit
+    public Map<LootTable, ResourceLocation> lootTableToKey = ImmutableMap.of(); // CraftBukkit // Paper - only store loot tables because those don't override equals and hashCode
 
     public LootDataManager() {}
 
@@ -101,8 +101,14 @@ public class LootDataManager implements PreparableReloadListener, LootDataResolv
         this.elements = map1;
         this.typeKeys = com_google_common_collect_immutablemultimap_builder.build();
         // CraftBukkit start - build a reversed registry map
-        ImmutableMap.Builder<Object, ResourceLocation> lootTableToKeyBuilder = ImmutableMap.builder();
-        this.elements.forEach((key, lootTable) -> lootTableToKeyBuilder.put((Object) lootTable, key.location()));
+        // Paper start - only create a map for loot tables
+        ImmutableMap.Builder<LootTable, ResourceLocation> lootTableToKeyBuilder = ImmutableMap.builder();
+        this.elements.forEach((lootDataId, value) -> {
+            if (lootDataId.type() == LootDataType.TABLE && value instanceof LootTable lootTable) {
+                lootTableToKeyBuilder.put(lootTable, lootDataId.location());
+            }
+        });
+        // Paper end
         this.lootTableToKey = lootTableToKeyBuilder.build();
         // CraftBukkit end
     }