Added support for using optional tags on Forge registries

Add DeferredRegister.key(name) helper function to make ResourceKey creation easier
Fix TagManager not binding tags
Fix Unbound Tag Exception when modders register tags during Register events Closes #10154

src/main/java/net/minecraftforge/registries/GameData.java

@@ -247,26 +247,32 @@ public class GameData {
     }
 
     @SuppressWarnings("deprecation")
-    public static void unfreezeData()
-    {
+    public static void unfreezeData() {
         LOGGER.debug(REGISTRIES, "Unfreezing vanilla registries");
         BuiltInRegistries.REGISTRY.stream().filter(r -> r instanceof MappedRegistry).forEach(r -> ((MappedRegistry<?>)r).unfreeze());
     }
 
-    public static void freezeData()
-    {
+    public static void freezeData() {
         LOGGER.debug(REGISTRIES, "Freezing registries");
-        BuiltInRegistries.REGISTRY.stream().filter(r -> r instanceof MappedRegistry).forEach(r -> ((MappedRegistry<?>)r).freeze());
-
-        for (Map.Entry<ResourceLocation, ForgeRegistry<?>> r : RegistryManager.ACTIVE.registries.entrySet())
-        {
-            loadRegistry(r.getKey(), RegistryManager.ACTIVE, RegistryManager.FROZEN, true);
+        for (var reg : BuiltInRegistries.REGISTRY) {
+            if (reg instanceof NamespacedWrapper<?> named) {
+                // This is called after we fire our register events, but before doesn't load any tags.
+                // So lets skip the validation for this pass and just make every unbound tag empty
+                // Tags will be bound later when tag data is reloaded/synced
+                named.bindAllUnboundTagsToEmpty();
+                named.freeze();
+            } else if (reg instanceof MappedRegistry maped)
+                maped.freeze();
         }
-        RegistryManager.FROZEN.registries.forEach((name, reg) ->
-        {
+
+        for (var r : RegistryManager.ACTIVE.registries.entrySet())
+            loadRegistry(r.getKey(), RegistryManager.ACTIVE, RegistryManager.FROZEN, true);
+
+        RegistryManager.FROZEN.registries.forEach((name, reg) -> {
             reg.validateContent(name);
             reg.freeze();
         });
+
         RegistryManager.ACTIVE.registries.forEach((name, reg) -> {
             reg.freeze();
             reg.bake();
@@ -764,6 +770,7 @@ public class GameData {
         int index = name.lastIndexOf(':');
         String oldPrefix = index == -1 ? "" : name.substring(0, index).toLowerCase(Locale.ROOT);
         name = index == -1 ? name : name.substring(index + 1);
+        @SuppressWarnings("removal")
         String prefix = ModLoadingContext.get().getActiveNamespace();
         if (warnOverrides && !oldPrefix.equals(prefix) && !oldPrefix.isEmpty())
         {