Fix creating the reverse map for loot table keys (#9766)

patches/server/1035-Fix-creating-the-reverse-map-for-loot-table-keys.patch

@@ -0,0 +1,36 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jake Potrebic <[email protected]>
+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
+     }