Cache JEResources villagers

src/main/java/org/embeddedt/modernfix/core/config/ModernFixEarlyConfig.java

@@ -23,6 +23,7 @@ public class ModernFixEarlyConfig {
         this.addMixinRule("feature.direct_stack_trace", false);
         this.addMixinRule("perf.fast_registry_validation", true);
         this.addMixinRule("perf.use_integrated_resources", true);
+        this.addMixinRule("perf.jeresources_startup", true);
         this.addMixinRule("perf.remove_biome_temperature_cache", true);
         this.addMixinRule("perf.resourcepacks", true);
         this.addMixinRule("perf.reduce_blockstate_cache_rebuilds", true);

src/main/java/org/embeddedt/modernfix/mixin/perf/jeresources_startup/VillagerEntryMixin.java

@@ -0,0 +1,35 @@
+package org.embeddedt.modernfix.mixin.perf.jeresources_startup;
+
+import jeresources.entry.VillagerEntry;
+import net.minecraft.client.Minecraft;
+import net.minecraft.world.entity.npc.Villager;
+import net.minecraft.world.level.Level;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+import java.lang.ref.WeakReference;
+
+/* Cache the created villager instead of reconstructing it every time */
+@Mixin(VillagerEntry.class)
+public class VillagerEntryMixin {
+    private WeakReference<Villager> cachedVillager = new WeakReference<>(null);
+
+    @Inject(method = "getVillagerEntity", at = @At("HEAD"), cancellable = true)
+    private void useCachedVillager(CallbackInfoReturnable<Villager> cir) {
+        Villager v = cachedVillager.get();
+        if(v != null) {
+            // Ensure we don't hold on to an old client world unnecessarily
+            Level cLevel = Minecraft.getInstance().level;
+            if(cLevel != null && v.getLevel() != cLevel)
+                v.setLevel(cLevel);
+            cir.setReturnValue(v);
+        }
+    }
+
+    @Inject(method = "getVillagerEntity", at = @At("RETURN"))
+    private void storeCachedVillager(CallbackInfoReturnable<Villager> cir) {
+        cachedVillager = new WeakReference<>(cir.getReturnValue());
+    }
+}

src/main/resources/modernfix.mixins.json

@@ -97,6 +97,7 @@
     "perf.reuse_datapacks.MinecraftServerMixin",
     "perf.use_integrated_resources.LootTableHelperMixin",
     "perf.use_integrated_resources.PiglinBarteringRecipeBuilderMixin",
+    "perf.jeresources_startup.VillagerEntryMixin",
     "bugfix.mc218112.SynchedEntityDataMixin_Client",
     "perf.faster_singleplayer_load.MinecraftServerMixin"
   ],