[1.21.x] Topologically sort reload listeners based on dependency ordering

patches/net/minecraft/server/packs/resources/ReloadableResourceManager.java.patch

@@ -1,13 +1,40 @@
 --- a/net/minecraft/server/packs/resources/ReloadableResourceManager.java
 +++ b/net/minecraft/server/packs/resources/ReloadableResourceManager.java
-@@ -73,4 +_,10 @@
+@@ -33,6 +_,12 @@
+         this.resources.close();
+     }
+
++    /**
++     * @deprecated Neo: Use {@link net.neoforged.neoforge.client.event.AddClientReloadListenerEvent}.
++     *
++     * @throws UnsupportedOperationException if called after the event has been fired.
++     */
++    @Deprecated
+     public void registerReloadListener(PreparableReloadListener p_10714_) {
+         this.listeners.add(p_10714_);
+     }
+@@ -72,5 +_,24 @@
+     @Override
      public Stream<PackResources> listPacks() {
          return this.resources.listPacks();
-     }
++    }
 +
-+    public void registerReloadListenerIfNotPresent(PreparableReloadListener listener) {
-+        if (!this.listeners.contains(listener)) {
-+            this.registerReloadListener(listener);
-+        }
++    /**
++     * Neo: Expose the reload listeners so they can be passed to the event.
++     *
++     * @return The (immutable) list of reload listeners.
++     */
++    public List<PreparableReloadListener> getListeners() {
++        return this.listeners;
 +    }
++
++    /**
++     * Neo: Updates the {@link #listeners} with the sorted list from the event.
++     *
++     * @implNote The returned list is immutable, so after this method is called, {@link #registerReloadListener(PreparableReloadListener)} will throw.
++     */
++    @org.jetbrains.annotations.ApiStatus.Internal
++    public void updateListenersFrom(net.neoforged.neoforge.event.SortedReloadListenerEvent event) {
++        this.listeners = net.neoforged.neoforge.resource.ReloadListenerSort.sort(event);
+     }
  }

src/main/java/net/neoforged/neoforge/client/ClientHooks.java

@@ -134,6 +134,7 @@
 import net.neoforged.fml.common.EventBusSubscriber;
 import net.neoforged.fml.common.asm.enumextension.ExtensionInfo;
 import net.neoforged.neoforge.client.entity.animation.json.AnimationTypeManager;
+import net.neoforged.neoforge.client.event.AddClientReloadListenerEvent;
 import net.neoforged.neoforge.client.event.AddSectionGeometryEvent;
 import net.neoforged.neoforge.client.event.CalculateDetachedCameraDistanceEvent;
 import net.neoforged.neoforge.client.event.CalculatePlayerTurnEvent;
@@ -151,7 +152,6 @@
 import net.neoforged.neoforge.client.event.InputEvent;
 import net.neoforged.neoforge.client.event.ModelEvent;
 import net.neoforged.neoforge.client.event.MovementInputUpdateEvent;
-import net.neoforged.neoforge.client.event.RegisterClientReloadListenersEvent;
 import net.neoforged.neoforge.client.event.RegisterColorHandlersEvent;
 import net.neoforged.neoforge.client.event.RegisterKeyMappingsEvent;
 import net.neoforged.neoforge.client.event.RegisterMaterialAtlasesEvent;
@@ -975,7 +975,11 @@ public static void initClientHooks(Minecraft mc, ReloadableResourceManager resou
         GameTestHooks.registerGametests();
         registerSpriteSourceTypes();
         MenuScreens.init();
-        ModLoader.postEvent(new RegisterClientReloadListenersEvent(resourceManager));
+
+        var rlEvent = new AddClientReloadListenerEvent(resourceManager);
+        ModLoader.postEvent(rlEvent);
+        resourceManager.updateListenersFrom(rlEvent);
+
         ModLoader.postEvent(new EntityRenderersEvent.RegisterLayerDefinitions());
         ModLoader.postEvent(new EntityRenderersEvent.RegisterRenderers());
         ModLoader.postEvent(new RegisterRenderStateModifiersEvent());

src/main/java/net/neoforged/neoforge/client/ClientNeoForgeMod.java

@@ -27,9 +27,9 @@
 import net.neoforged.fml.config.ModConfigs;
 import net.neoforged.neoforge.client.color.item.FluidContentsTint;
 import net.neoforged.neoforge.client.entity.animation.json.AnimationLoader;
+import net.neoforged.neoforge.client.event.AddClientReloadListenerEvent;
 import net.neoforged.neoforge.client.event.ClientPlayerNetworkEvent;
 import net.neoforged.neoforge.client.event.ModelEvent;
-import net.neoforged.neoforge.client.event.RegisterClientReloadListenersEvent;
 import net.neoforged.neoforge.client.event.RegisterColorHandlersEvent;
 import net.neoforged.neoforge.client.event.RegisterItemModelsEvent;
 import net.neoforged.neoforge.client.event.RegisterNamedRenderTypesEvent;
@@ -38,6 +38,7 @@
 import net.neoforged.neoforge.client.extensions.common.RegisterClientExtensionsEvent;
 import net.neoforged.neoforge.client.gui.ConfigurationScreen;
 import net.neoforged.neoforge.client.gui.IConfigScreenFactory;
+import net.neoforged.neoforge.client.loading.ClientModLoader;
 import net.neoforged.neoforge.client.model.EmptyModel;
 import net.neoforged.neoforge.client.model.UnbakedCompositeModel;
 import net.neoforged.neoforge.client.model.item.DynamicFluidContainerModel;
@@ -64,7 +65,10 @@
 import net.neoforged.neoforge.common.data.internal.VanillaSoundDefinitionsProvider;
 import net.neoforged.neoforge.common.util.SelfTest;
 import net.neoforged.neoforge.data.event.GatherDataEvent;
+import net.neoforged.neoforge.internal.BrandingControl;
 import net.neoforged.neoforge.internal.versions.neoforge.NeoForgeVersion;
+import net.neoforged.neoforge.resource.NeoForgeReloadListeners;
+import net.neoforged.neoforge.resource.VanillaClientListeners;
 import org.jetbrains.annotations.ApiStatus;
 
 @ApiStatus.Internal
@@ -131,9 +135,16 @@ static void onRegisterModelLoaders(ModelEvent.RegisterLoaders event) {
     }
 
     @SubscribeEvent
-    static void onRegisterReloadListeners(RegisterClientReloadListenersEvent event) {
-        event.registerReloadListener(ObjLoader.INSTANCE);
-        event.registerReloadListener(AnimationLoader.INSTANCE);
+    static void onRegisterReloadListeners(AddClientReloadListenerEvent event) {
+        event.addListener(NeoForgeReloadListeners.CLIENT_MOD_LOADING, ClientModLoader::onResourceReload);
+        event.addListener(NeoForgeReloadListeners.BRANDING, BrandingControl.resourceManagerReloadListener());
+
+        // These run before vanilla reload listeners, so we add them before LANGUAGE, the first vanilla one.
+        event.addDependency(NeoForgeReloadListeners.CLIENT_MOD_LOADING, NeoForgeReloadListeners.BRANDING);
+        event.addDependency(NeoForgeReloadListeners.BRANDING, VanillaClientListeners.LANGUAGE);
+
+        event.addListener(NeoForgeReloadListeners.OBJ_LOADER, ObjLoader.INSTANCE);
+        event.addListener(NeoForgeReloadListeners.ENTITY_ANIMATIONS, AnimationLoader.INSTANCE);
     }
 
     @SubscribeEvent

src/main/java/net/neoforged/neoforge/client/event/AddClientReloadListenerEvent.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.neoforged.neoforge.client.event;
+
+import net.minecraft.client.Minecraft;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.packs.resources.PreparableReloadListener;
+import net.minecraft.server.packs.resources.ReloadableResourceManager;
+import net.neoforged.fml.LogicalSide;
+import net.neoforged.fml.event.IModBusEvent;
+import net.neoforged.neoforge.event.SortedReloadListenerEvent;
+import net.neoforged.neoforge.resource.VanillaClientListeners;
+import org.jetbrains.annotations.ApiStatus;
+
+/**
+ * This event allows mods to register client-side reload listeners to the resource manager.
+ * This event is fired once during the construction of the {@link Minecraft} instance.
+ * <p>
+ * This event is only fired on the {@linkplain LogicalSide#CLIENT logical client}.
+ * 
+ * @see {@link AddReloadListenerEvent} for registering server-side reload listeners.
+ */
+public class AddClientReloadListenerEvent extends SortedReloadListenerEvent implements IModBusEvent {
+    @ApiStatus.Internal
+    public AddClientReloadListenerEvent(ReloadableResourceManager resourceManager) {
+        super(resourceManager.getListeners(), AddClientReloadListenerEvent::lookupName);
+    }
+
+    private static ResourceLocation lookupName(PreparableReloadListener listener) {
+        ResourceLocation key = VanillaClientListeners.getNameForClass(listener.getClass());
+        if (key == null) {
+            if (listener.getClass().getPackageName().startsWith("net.minecraft")) {
+                throw new IllegalArgumentException("A key for the reload listener " + listener + " was not provided in VanillaClientListeners!");
+            } else {
+                throw new IllegalArgumentException("A non-vanilla reload listener " + listener + " was added via mixin before the AddClientReloadListenerEvent! Mod-added listeners must go through the event.");
+            }
+        }
+        return key;
+    }
+}

src/main/java/net/neoforged/neoforge/client/loading/ClientModLoader.java

@@ -28,7 +28,6 @@
 import net.neoforged.neoforge.common.NeoForge;
 import net.neoforged.neoforge.common.NeoForgeConfig;
 import net.neoforged.neoforge.common.util.LogicalSidedProvider;
-import net.neoforged.neoforge.internal.BrandingControl;
 import net.neoforged.neoforge.internal.CommonModLoader;
 import net.neoforged.neoforge.logging.CrashReportExtender;
 import net.neoforged.neoforge.resource.ResourcePackLoader;
@@ -63,12 +62,15 @@ public static void begin(final Minecraft minecraft, final PackRepository default
         if (error == null) {
             ResourcePackLoader.populatePackRepository(defaultResourcePacks, PackType.CLIENT_RESOURCES, false);
             DataPackConfig.DEFAULT.addModPacks(ResourcePackLoader.getPackNames(PackType.SERVER_DATA));
-            mcResourceManager.registerReloadListener(ClientModLoader::onResourceReload);
-            mcResourceManager.registerReloadListener(BrandingControl.resourceManagerReloadListener());
         }
     }
 
-    private static CompletableFuture<Void> onResourceReload(final PreparableReloadListener.PreparationBarrier stage, final ResourceManager resourceManager, final Executor asyncExecutor, final Executor syncExecutor) {
+    /**
+     * This method can be bound as a method reference to {@link PreparableReloadListener}.
+     * <p>
+     * It is used as the entrypoint for client mod loading, which starts when {@link Minecraft} triggers the first resource reload.
+     */
+    public static CompletableFuture<Void> onResourceReload(final PreparableReloadListener.PreparationBarrier stage, final ResourceManager resourceManager, final Executor asyncExecutor, final Executor syncExecutor) {
         return CompletableFuture.runAsync(() -> startModLoading(syncExecutor, asyncExecutor), ModWorkManager.parallelExecutor())
                 .thenCompose(stage::wait)
                 .thenRunAsync(() -> finishModLoading(syncExecutor, asyncExecutor), ModWorkManager.parallelExecutor());

src/main/java/net/neoforged/neoforge/client/model/UnbakedModelLoader.java

@@ -11,17 +11,17 @@
 import net.minecraft.client.renderer.block.model.BlockModel;
 import net.minecraft.client.resources.model.UnbakedModel;
 import net.minecraft.server.packs.resources.ResourceManagerReloadListener;
+import net.neoforged.neoforge.client.event.AddClientReloadListenerEvent;
 import net.neoforged.neoforge.client.event.ModelEvent;
-import net.neoforged.neoforge.client.event.RegisterClientReloadListenersEvent;
 
 /**
  * A loader for custom {@linkplain UnbakedModel unbaked models}.
  * <p>
  * If you do any caching, you should implement {@link ResourceManagerReloadListener} and register it with
- * {@link RegisterClientReloadListenersEvent}.
+ * {@link AddClientReloadListenerEvent}.
  *
  * @see ModelEvent.RegisterLoaders
- * @see RegisterClientReloadListenersEvent
+ * @see AddClientReloadListenerEvent
  */
 public interface UnbakedModelLoader<T extends UnbakedModel> {
     /**

src/main/java/net/neoforged/neoforge/common/NeoForgeEventHandler.java

@@ -39,12 +39,16 @@
 import net.neoforged.neoforge.network.payload.RegistryDataMapSyncPayload;
 import net.neoforged.neoforge.registries.DataMapLoader;
 import net.neoforged.neoforge.registries.RegistryManager;
+import net.neoforged.neoforge.resource.NeoForgeReloadListeners;
 import net.neoforged.neoforge.server.command.ConfigCommand;
 import net.neoforged.neoforge.server.command.NeoForgeCommand;
 import org.jetbrains.annotations.ApiStatus;
 
 @ApiStatus.Internal
 public class NeoForgeEventHandler {
+    private static LootModifierManager LOOT_MODIFIER_MANAGER;
+    private static DataMapLoader DATA_MAP_LOADER;
+
     @SubscribeEvent(priority = EventPriority.HIGH)
     public void onEntityJoinWorld(EntityJoinLevelEvent event) {
         Entity entity = event.getEntity();
@@ -102,7 +106,7 @@ public void playerLogin(PlayerEvent.PlayerLoggedInEvent event) {
     @SubscribeEvent
     public void tagsUpdated(TagsUpdatedEvent event) {
         if (event.getUpdateCause() == TagsUpdatedEvent.UpdateCause.SERVER_DATA_LOAD) {
-            DATA_MAPS.apply();
+            DATA_MAP_LOADER.apply();
         }
     }
 
@@ -146,25 +150,17 @@ public void onCommandsRegister(RegisterCommandsEvent event) {
         ConfigCommand.register(event.getDispatcher());
     }
 
-    private static LootModifierManager INSTANCE;
-    private static DataMapLoader DATA_MAPS;
-
     @SubscribeEvent
     public void onResourceReload(AddReloadListenerEvent event) {
-        INSTANCE = new LootModifierManager();
-        event.addListener(INSTANCE);
-        event.addListener(DATA_MAPS = new DataMapLoader(event.getConditionContext(), event.getRegistryAccess()));
+        event.addListener(NeoForgeReloadListeners.LOOT_MODIFIERS, LOOT_MODIFIER_MANAGER = new LootModifierManager());
+        event.addListener(NeoForgeReloadListeners.DATA_MAPS, DATA_MAP_LOADER = new DataMapLoader(event.getConditionContext(), event.getRegistryAccess()));
+        event.addListener(NeoForgeReloadListeners.CREATIVE_TABS, CreativeModeTabRegistry.getReloadListener());
     }
 
     static LootModifierManager getLootModifierManager() {
-        if (INSTANCE == null)
+        if (LOOT_MODIFIER_MANAGER == null)
             throw new IllegalStateException("Can not retrieve LootModifierManager until resources have loaded once.");
-        return INSTANCE;
-    }
-
-    @SubscribeEvent
-    public void resourceReloadListeners(AddReloadListenerEvent event) {
-        event.addListener(CreativeModeTabRegistry.getReloadListener());
+        return LOOT_MODIFIER_MANAGER;
     }
 
     @SubscribeEvent(priority = EventPriority.HIGHEST)

src/main/java/net/neoforged/neoforge/common/util/VanillaClassToKey.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) NeoForged and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.neoforged.neoforge.common.util;
+
+import net.minecraft.resources.ResourceLocation;
+import org.jetbrains.annotations.ApiStatus;
+import org.spongepowered.include.com.google.common.base.Preconditions;
+
+@ApiStatus.Internal
+public class VanillaClassToKey {
+    /**
+     * Converts a vanilla class name into an identifier compliant with the rules set by {@link ResourceLocation}.
+     * <p>
+     * This conversion is done by translating all uppercase characters into an underscore plus the lowercase version of the original character.
+     * 
+     * @param cls The class to convert.
+     * @return A lower_snake_case representation of that class's original PascalCase name.
+     * @throws IllegalArgumentException if the class is not from Minecraft, or if the class does not have a {@link Class#getSimpleName() simple name}.
+     */
+    public static ResourceLocation convert(Class<?> cls) {
+        Preconditions.checkArgument(cls.getPackageName().startsWith("net.minecraft"), "Automatic name conversion can only be applied to net.minecraft classes. Provided: " + cls.getName());
+        Preconditions.checkArgument(!cls.getSimpleName().isEmpty(), "Automatic name conversion can only happen for identifiable classes (per Class#getSimpleName()). Provided: " + cls.getName());
+
+        StringBuilder sb = new StringBuilder();
+        cls.getSimpleName().chars().mapMulti((value, consumer) -> {
+            if (Character.isUpperCase((char) value)) {
+                consumer.accept('_');
+                consumer.accept(Character.toLowerCase((char) value));
+            } else {
+                consumer.accept(value);
+            }
+        }).forEach(i -> sb.append((char) i));
+
+        return ResourceLocation.withDefaultNamespace(sb.substring(1)); // The string will be prefixed with an additional `_` since the first character is uppercase.
+    }
+}