Add in registry registration events, new subscription events you can use to make sure you're registering things at the "best" time.

src/main/java/net/minecraftforge/client/event/ModelRegistryEvent.java

@@ -0,0 +1,29 @@
+/*
+ * Minecraft Forge
+ * Copyright (c) 2016.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation version 2.1
+ * of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+package net.minecraftforge.client.event;
+
+import net.minecraftforge.fml.common.eventhandler.Event;
+
+/**
+ * Fired when the {@link net.minecraftforge.client.model.ModelLoader} is ready to receive registrations
+ */
+public class ModelRegistryEvent extends Event
+{
+}

src/main/java/net/minecraftforge/event/RegistryEvent.java

@@ -0,0 +1,77 @@
+/*
+ * Minecraft Forge
+ * Copyright (c) 2016.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation version 2.1
+ * of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+package net.minecraftforge.event;
+
+import net.minecraft.util.ResourceLocation;
+import net.minecraftforge.fml.common.eventhandler.Event;
+import net.minecraftforge.fml.common.eventhandler.GenericEvent;
+import net.minecraftforge.fml.common.registry.IForgeRegistry;
+import net.minecraftforge.fml.common.registry.IForgeRegistryEntry;
+import net.minecraftforge.fml.common.registry.PersistentRegistryManager;
+
+
+/**
+ * RegistryEvent supertype.
+ */
+public class RegistryEvent<T extends IForgeRegistryEntry<T>> extends GenericEvent<T>
+{
+    RegistryEvent(Class<T> clazz) {
+        super(clazz);
+    }
+    /**
+     * Register new registries when you receive this event, through the {@link PersistentRegistryManager}
+     */
+    public static class NewRegistry extends Event {
+    }
+
+    /**
+     * Register your objects for the appropriate registry type when you receive this event.
+     *
+     * <code>event.getRegistry().register(...)</code>
+     *
+     * The registries will be visited in alphabetic order of their name, except blocks and items,
+     * which will be visited FIRST and SECOND respectively.
+     *
+     * ObjectHolders will reload between Blocks and Items, and after all registries have been visited.
+     * @param <T> The registry top level type
+     */
+    public static class Register<T extends IForgeRegistryEntry<T>> extends RegistryEvent<T> {
+        private final IForgeRegistry<T> registry;
+        private final ResourceLocation location;
+
+        public Register(ResourceLocation location, IForgeRegistry<T> registry)
+        {
+            super(registry.getRegistrySuperType());
+            this.location = location;
+            this.registry = registry;
+        }
+
+        public IForgeRegistry<T> getRegistry()
+        {
+            return registry;
+        }
+
+        public ResourceLocation getLocation()
+        {
+            return location;
+        }
+
+    }
+}

src/main/java/net/minecraftforge/fml/client/FMLClientHandler.java

@@ -76,7 +76,9 @@ import net.minecraft.util.StringUtils;
 import net.minecraft.world.WorldSettings;
 import net.minecraft.world.storage.WorldSummary;
 import net.minecraft.world.storage.SaveFormatOld;
+import net.minecraftforge.client.event.ModelRegistryEvent;
 import net.minecraftforge.common.ForgeModContainer;
+import net.minecraftforge.common.MinecraftForge;
 import net.minecraftforge.fml.client.registry.RenderingRegistry;
 import net.minecraftforge.fml.common.DummyModContainer;
 import net.minecraftforge.fml.common.DuplicateModsFoundException;
@@ -1038,4 +1040,10 @@ public class FMLClientHandler implements IFMLSidedHandler
     {
         this.client.renderGlobal.loadRenderers();
     }
+
+    @Override
+    public void fireSidedRegistryEvents()
+    {
+        MinecraftForge.EVENT_BUS.post(new ModelRegistryEvent());
+    }
 }

src/main/java/net/minecraftforge/fml/common/AutomaticEventSubscriber.java

@@ -0,0 +1,77 @@
+/*
+ * Minecraft Forge
+ * Copyright (c) 2016.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation version 2.1
+ * of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+package net.minecraftforge.fml.common;
+
+import com.google.common.base.Strings;
+import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.fml.common.discovery.ASMDataTable;
+import net.minecraftforge.fml.common.discovery.asm.ModAnnotation;
+import net.minecraftforge.fml.relauncher.Side;
+import org.apache.logging.log4j.Level;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+import java.util.Arrays;
+import java.util.EnumSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Automatic eventbus subscriber - reads {@link net.minecraftforge.fml.common.Mod.EventBusSubscriber}
+ * annotations and passes the class instances to the {@link net.minecraftforge.common.MinecraftForge.EVENT_BUS}
+ */
+public class AutomaticEventSubscriber
+{
+    private static final EnumSet<Side> DEFAULT = EnumSet.allOf(Side.class);
+    public static void inject(ModContainer mod, ASMDataTable data, Side side)
+    {
+        FMLLog.fine("Attempting to inject @EventBusSubscriber classes into the eventbus for %s", mod.getModId());
+        Set<ASMDataTable.ASMData> targets = data.getAnnotationsFor(mod).get(Mod.EventBusSubscriber.class.getName());
+        ClassLoader mcl = Loader.instance().getModClassLoader();
+
+        for (ASMDataTable.ASMData targ : targets)
+        {
+            try
+            {
+                //noinspection unchecked
+                List<ModAnnotation.EnumHolder> sidesEnum = (List<ModAnnotation.EnumHolder>)targ.getAnnotationInfo().get("value");
+                EnumSet<Side> sides = DEFAULT;
+                if (sidesEnum != null) {
+                    sides = EnumSet.noneOf(Side.class);
+                    for (ModAnnotation.EnumHolder h: sidesEnum) {
+                        sides.add(Side.valueOf(h.getValue()));
+                    }
+                }
+                if (sides == DEFAULT || sides.contains(side)) {
+                    FMLLog.fine("Found @EventBusSubscriber class %s", targ.getClassName());
+                    Class<?> subscriptionTarget = Class.forName(targ.getClassName(), true, mcl);
+                    MinecraftForge.EVENT_BUS.register(subscriptionTarget);
+                    FMLLog.fine("Injected @EventBusSubscriber class %s", targ.getClassName());
+                }
+            }
+            catch (Exception e)
+            {
+                FMLLog.log(Level.ERROR, e, "An error occurred trying to load an EventBusSubscriber %s for modid %s", targ.getClassName(), mod.getModId());
+                throw new LoaderException(e);
+            }
+        }
+    }
+
+}

src/main/java/net/minecraftforge/fml/common/FMLCommonHandler.java

@@ -746,4 +746,9 @@ public class FMLCommonHandler
     public void reloadRenderers() {
         sidedDelegate.reloadRenderers();
     }
+
+    public void fireSidedRegistryEvents()
+    {
+        sidedDelegate.fireSidedRegistryEvents();
+    }
 }

src/main/java/net/minecraftforge/fml/common/FMLModContainer.java

@@ -573,6 +573,8 @@ public class FMLModContainer implements ModContainer
                 eventBus.post(new FMLFingerprintViolationEvent(source.isDirectory(), source, ImmutableSet.copyOf(this.sourceFingerprints), expectedFingerprint));
             }
             ProxyInjector.inject(this, event.getASMHarvestedData(), FMLCommonHandler.instance().getSide(), getLanguageAdapter());
+            AutomaticEventSubscriber.inject(this, event.getASMHarvestedData(), FMLCommonHandler.instance().getSide());
+
             processFieldAnnotations(event.getASMHarvestedData());
         }
         catch (Throwable e)

src/main/java/net/minecraftforge/fml/common/IFMLSidedHandler.java

@@ -75,4 +75,6 @@ public interface IFMLSidedHandler
     String stripSpecialChars(String message);
 
     void reloadRenderers();
+
+    void fireSidedRegistryEvents();
 }

src/main/java/net/minecraftforge/fml/common/Loader.java

@@ -604,6 +604,8 @@ public class Loader
         ObjectHolderRegistry.INSTANCE.findObjectHolders(discoverer.getASMTable());
         ItemStackHolderInjector.INSTANCE.findHolders(discoverer.getASMTable());
         CapabilityManager.INSTANCE.injectCapabilities(discoverer.getASMTable());
+        PersistentRegistryManager.fireRegistryEvents();
+        FMLCommonHandler.instance().fireSidedRegistryEvents();
         modController.distributeStateMessage(LoaderState.PREINITIALIZATION, discoverer.getASMTable(), canonicalConfigDir);
         ObjectHolderRegistry.INSTANCE.applyObjectHolders();
         ItemStackHolderInjector.INSTANCE.inject();

src/main/java/net/minecraftforge/fml/common/Mod.java

@@ -39,6 +39,7 @@ import net.minecraftforge.fml.common.event.FMLServerStoppingEvent;
 import net.minecraftforge.fml.common.event.FMLInterModComms.IMCEvent;
 import net.minecraftforge.fml.common.network.NetworkCheckHandler;
 import net.minecraftforge.fml.common.registry.GameRegistry;
+import net.minecraftforge.fml.relauncher.Side;
 
 /**
  * This defines a Mod to FML.
@@ -305,4 +306,13 @@ public @interface Mod
     @Target(ElementType.METHOD)
     public @interface InstanceFactory {
     }
+
+    /**
+     * A class which will be subscribed to {@link net.minecraftforge.common.MinecraftForge.EVENT_BUS} at mod construction time.
+     */
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target(ElementType.TYPE)
+    public @interface EventBusSubscriber {
+        Side[] value() default { Side.CLIENT, Side.SERVER };
+    }
 }

src/main/java/net/minecraftforge/fml/common/eventhandler/ASMEventHandler.java

@@ -68,11 +68,9 @@ public class ASMEventHandler implements IEventListener
         if (isGeneric)
         {
             java.lang.reflect.Type type = method.getGenericParameterTypes()[0];
-            System.currentTimeMillis();
             if (type instanceof ParameterizedType)
             {
                 filter = ((ParameterizedType)type).getActualTypeArguments()[0];
-                System.currentTimeMillis();
             }
         }
     }

src/main/java/net/minecraftforge/fml/common/registry/FMLControlledNamespacedRegistry.java

@@ -36,6 +36,7 @@ import com.google.common.collect.Iterators;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
+import net.minecraftforge.event.RegistryEvent;
 import org.apache.commons.lang3.Validate;
 import org.apache.logging.log4j.Level;
 
@@ -830,6 +831,13 @@ public class FMLControlledNamespacedRegistry<I extends IForgeRegistryEntry<I>> e
         add(-1, key, value);
     }
 
+    public void registerAll(I... values)
+    {
+        for (I value: values)
+        {
+            register(value);
+        }
+    }
     @Override
     public boolean containsValue(I value)
     {
@@ -908,4 +916,10 @@ public class FMLControlledNamespacedRegistry<I extends IForgeRegistryEntry<I>> e
     {
         return (T)slaves.get(slaveMapName);
     }
+
+    RegistryEvent.Register<I> buildRegistryRegisterEvent(ResourceLocation location)
+    {
+        return new RegistryEvent.Register<I>(location, this);
+    }
+
 }

src/main/java/net/minecraftforge/fml/common/registry/IForgeRegistry.java

@@ -39,6 +39,8 @@ public interface IForgeRegistry<V extends IForgeRegistryEntry<V>> extends Iterab
 
     void register(V value);
 
+    void registerAll(V... values);
+
     boolean containsKey(ResourceLocation key);
     boolean containsValue(V value);
 

src/main/java/net/minecraftforge/fml/common/registry/IForgeRegistryEntry.java

@@ -89,7 +89,6 @@ public interface IForgeRegistryEntry<V>
         //Helper functions
         public final T setRegistryName(ResourceLocation name){ return setRegistryName(name.toString()); }
         public final T setRegistryName(String modID, String name){ return setRegistryName(modID + ":" + name); }
-
         public final ResourceLocation getRegistryName()
         {
             if (delegate.name() != null) return delegate.name();

src/main/java/net/minecraftforge/fml/common/registry/PersistentRegistryManager.java

@@ -20,8 +20,9 @@
 package net.minecraftforge.fml.common.registry;
 
 import java.io.IOException;
-import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.util.Collections;
+import java.util.Comparator;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
@@ -33,6 +34,8 @@ import net.minecraft.block.Block;
 import net.minecraft.block.BlockAir;
 import net.minecraft.item.Item;
 import net.minecraft.util.ResourceLocation;
+import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.event.RegistryEvent;
 import net.minecraftforge.fml.common.EnhancedRuntimeException;
 import net.minecraftforge.fml.common.FMLCommonHandler;
 import net.minecraftforge.fml.common.FMLLog;
@@ -64,6 +67,35 @@ import com.google.common.collect.Sets.SetView;
 @SuppressWarnings("WeakerAccess")
 public class PersistentRegistryManager
 {
+    public static void fireRegistryEvents()
+    {
+        MinecraftForge.EVENT_BUS.post(new RegistryEvent.NewRegistry());
+
+        List<ResourceLocation> registryKeys = Lists.newArrayList(PersistentRegistry.ACTIVE.registries.keySet());
+        Collections.sort(registryKeys, new Comparator<ResourceLocation>()
+        {
+            @Override
+            public int compare(ResourceLocation o1, ResourceLocation o2)
+            {
+                return o1.toString().compareToIgnoreCase(o2.toString());
+            }
+        });
+        fireRegistryEvent(PersistentRegistry.ACTIVE.registries, BLOCKS);
+        ObjectHolderRegistry.INSTANCE.applyObjectHolders(); // inject any blocks
+        fireRegistryEvent(PersistentRegistry.ACTIVE.registries, ITEMS);
+        ObjectHolderRegistry.INSTANCE.applyObjectHolders(); // inject any items
+        for (ResourceLocation rl : registryKeys) {
+            if (rl == BLOCKS || rl == ITEMS) continue;
+            fireRegistryEvent(PersistentRegistry.ACTIVE.registries, rl);
+        }
+        ObjectHolderRegistry.INSTANCE.applyObjectHolders(); // inject everything else
+    }
+    private static void fireRegistryEvent(BiMap<ResourceLocation, FMLControlledNamespacedRegistry<?>> registries, ResourceLocation name)
+    {
+        final RegistryEvent.Register<?> event = registries.get(name).buildRegistryRegisterEvent(name);
+        MinecraftForge.EVENT_BUS.post(event);
+    }
+
     enum PersistentRegistry
     {
         ACTIVE, VANILLA, FROZEN, STAGING;

src/main/java/net/minecraftforge/fml/server/FMLServerHandler.java

@@ -332,6 +332,11 @@ public class FMLServerHandler implements IFMLSidedHandler
     @Override
     public void reloadRenderers() {
         // NOOP
+    }
 
+    @Override
+    public void fireSidedRegistryEvents()
+    {
+        // NOOP
     }
 }