Expose loaded RegistryAccess through AddReloadListenerEvent (#9613)

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

@@ -6,6 +6,7 @@
 package net.minecraftforge.event;
 
 import com.google.common.collect.ImmutableList;
+import net.minecraft.core.RegistryAccess;
 import net.minecraft.server.ReloadableServerResources;
 import net.minecraft.util.profiling.ProfilerFiller;
 import net.minecraft.server.packs.resources.PreparableReloadListener;
@@ -30,10 +31,12 @@ public class AddReloadListenerEvent extends Event
 {
     private final List<PreparableReloadListener> listeners = new ArrayList<>();
     private final ReloadableServerResources serverResources;
+    private final RegistryAccess registryAccess;
 
-    public AddReloadListenerEvent(ReloadableServerResources serverResources)
+    public AddReloadListenerEvent(ReloadableServerResources serverResources, RegistryAccess registryAccess)
     {
         this.serverResources = serverResources;
+        this.registryAccess = registryAccess;
     }
 
    /**
@@ -66,6 +69,16 @@ public class AddReloadListenerEvent extends Event
         return serverResources.getConditionContext();
     }
 
+    /**
+     * Provides access to the loaded registries associated with these server resources.
+     * All built-in and dynamic registries are loaded and frozen by this point.
+     * @return The RegistryAccess context for the currently active reload.
+     */
+    public RegistryAccess getRegistryAccess()
+    {
+        return registryAccess;
+    }
+
     private static class WrappedStateAwareListener implements PreparableReloadListener {
         private final PreparableReloadListener wrapped;
 

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

@@ -18,6 +18,7 @@ import net.minecraft.advancements.Advancement;
 import net.minecraft.advancements.AdvancementProgress;
 import net.minecraft.commands.CommandBuildContext;
 import net.minecraft.core.Holder;
+import net.minecraft.core.RegistryAccess;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.ReloadableServerResources;
 import net.minecraft.server.level.ChunkHolder;
@@ -758,9 +759,9 @@ public class ForgeEventFactory
         return event.getNewTime();
     }
 
-    public static List<PreparableReloadListener> onResourceReload(ReloadableServerResources serverResources)
+    public static List<PreparableReloadListener> onResourceReload(ReloadableServerResources serverResources, RegistryAccess registryAccess)
     {
-        AddReloadListenerEvent event = new AddReloadListenerEvent(serverResources);
+        AddReloadListenerEvent event = new AddReloadListenerEvent(serverResources, registryAccess);
         MinecraftForge.EVENT_BUS.post(event);
         return event.getListeners();
     }