From eae9b9145d99699e9105010f32924dffc4017460 Mon Sep 17 00:00:00 2001
From: LexManos <LexManos@gmail.com>
Date: Tue, 12 Aug 2025 18:02:33 -0700
Subject: [PATCH] Optimize VillagerTradingManager, avoid redundant work. Closes
 #10577

---
 settings.gradle                               |  4 ++--
 .../common/VillagerTradingManager.java        | 21 ++++++++++++-------
 2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/settings.gradle b/settings.gradle
index e696e17b27..4545965c48 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -32,8 +32,8 @@ dependencyResolutionManagement {
             library('accesstransformers', 'net.minecraftforge:accesstransformers:8.2.2')
             library('coremods', 'net.minecraftforge:coremods:5.2.6')
             library('nashorn', 'org.openjdk.nashorn:nashorn-core:15.4') // Needed by coremods, because the JRE no longer ships JS
-            library('eventbus', 'net.minecraftforge:eventbus:7.0-beta.10')
-            library('eventbus-validator', 'net.minecraftforge:eventbus-validator:7.0-beta.10')
+            library('eventbus', 'net.minecraftforge:eventbus:7.0-beta.11')
+            library('eventbus-validator', 'net.minecraftforge:eventbus-validator:7.0-beta.11')
             library('mergetool-api', 'net.minecraftforge:mergetool-api:1.0')
 
             library('mixin', 'org.spongepowered:mixin:0.8.7')
diff --git a/src/main/java/net/minecraftforge/common/VillagerTradingManager.java b/src/main/java/net/minecraftforge/common/VillagerTradingManager.java
index 413e76f295..c0bb3dfb4f 100644
--- a/src/main/java/net/minecraftforge/common/VillagerTradingManager.java
+++ b/src/main/java/net/minecraftforge/common/VillagerTradingManager.java
@@ -20,23 +20,25 @@ import net.minecraft.world.entity.npc.VillagerTrades.ItemListing;
 import net.minecraft.core.NonNullList;
 import net.minecraftforge.event.village.VillagerTradesEvent;
 import net.minecraftforge.event.village.WandererTradesEvent;
+import net.minecraftforge.common.util.Lazy;
 import net.minecraftforge.event.server.ServerAboutToStartEvent;
 import net.minecraftforge.registries.ForgeRegistries;
 import org.apache.commons.lang3.tuple.Pair;
 
 public class VillagerTradingManager {
-    private static final Map<ResourceKey<VillagerProfession>, Int2ObjectMap<ItemListing[]>> VANILLA_TRADES = new HashMap<>();
-    private static final List<Pair<ItemListing[], Integer>> WANDERER_TRADES = new ArrayList<>();
+    private static final Lazy<Map<ResourceKey<VillagerProfession>, Int2ObjectMap<ItemListing[]>>> VANILLA_TRADES = Lazy.of(VillagerTradingManager::copyVanillaTrades);
+    private static final Lazy<List<Pair<ItemListing[], Integer>>> WANDERER_TRADES = Lazy.of(() -> new ArrayList<Pair<ItemListing[], Integer>>(VillagerTrades.WANDERING_TRADER_TRADES));
 
-    static {
+    private static Map<ResourceKey<VillagerProfession>, Int2ObjectMap<ItemListing[]>> copyVanillaTrades() {
+        var ret = new HashMap<ResourceKey<VillagerProfession>, Int2ObjectMap<ItemListing[]>>();
         VillagerTrades.TRADES.forEach((key, value) -> {
             Int2ObjectMap<ItemListing[]> copy = new Int2ObjectOpenHashMap<>();
             for (var ent : value.int2ObjectEntrySet()) {
                 copy.put(ent.getIntKey(), Arrays.copyOf(ent.getValue(), ent.getValue().length));
             }
-            VANILLA_TRADES.put(key, copy);
+            ret.put(key, copy);
         });
-        WANDERER_TRADES.addAll(VillagerTrades.WANDERING_TRADER_TRADES);
+        return ret;
     }
 
     static void loadTrades(ServerAboutToStartEvent e) {
@@ -46,7 +48,9 @@ public class VillagerTradingManager {
 
     /** Posts the WandererTradesEvent. */
     private static void postWandererEvent() {
-        var event = WandererTradesEvent.BUS.fire(new WandererTradesEvent(WANDERER_TRADES));
+        if (!WandererTradesEvent.BUS.hasListeners())
+            return;
+        var event = WandererTradesEvent.BUS.fire(new WandererTradesEvent(WANDERER_TRADES.get()));
         VillagerTrades.WANDERING_TRADER_TRADES.clear();
         for (var pool : event.getPools())
             VillagerTrades.WANDERING_TRADER_TRADES.add(Pair.of(pool.getEntries().toArray(ItemListing[]::new), pool.getRolls()));
@@ -54,10 +58,13 @@ public class VillagerTradingManager {
 
     /** Posts a VillagerTradesEvent for each registered profession. */
     private static void postVillagerEvents() {
+        if (!VillagerTradesEvent.BUS.hasListeners())
+            return;
         // TODO [VillagerType][1.21.5] Villager Professions are stored as keys in vanilla now? Re-evaluate this.
+        var vanilla = VANILLA_TRADES.get();
         for (VillagerProfession value : ForgeRegistries.VILLAGER_PROFESSIONS) {
             var prof = ForgeRegistries.VILLAGER_PROFESSIONS.getResourceKey(value).orElseThrow();
-            Int2ObjectMap<ItemListing[]> trades = VANILLA_TRADES.getOrDefault(prof, new Int2ObjectOpenHashMap<>());
+            Int2ObjectMap<ItemListing[]> trades = vanilla.getOrDefault(prof, new Int2ObjectOpenHashMap<>());
             Int2ObjectMap<List<ItemListing>> mutableTrades = new Int2ObjectOpenHashMap<>();
             for (int i = 1; i < 6; i++)
                 mutableTrades.put(i, NonNullList.create());