Load Modded Datapacks in DatapackScreen, before world creation (#6913)

src/main/java/net/minecraftforge/common/ForgeHooks.java

@@ -139,6 +139,7 @@ import net.minecraftforge.event.world.BlockEvent;
 import net.minecraftforge.event.world.NoteBlockEvent;
 import net.minecraftforge.eventbus.api.Event.Result;
 import net.minecraftforge.fluids.FluidAttributes;
+import net.minecraftforge.fml.packs.ResourcePackLoader;
 import net.minecraftforge.registries.DataSerializerEntry;
 import net.minecraftforge.registries.ForgeRegistries;
 import net.minecraftforge.registries.ForgeRegistry;
@@ -1231,4 +1232,19 @@ public class ForgeHooks
             locations.stream().map(ResourceLocation::toString).forEach(array::add);
         }
     }
+
+    public static List<String> getModPacks()
+    {
+        List<String> modpacks = ResourcePackLoader.getPackNames();
+        if(modpacks.isEmpty())
+            throw new IllegalStateException("Attempted to retrieve mod packs before they were loaded in!");
+        return modpacks;
+    }
+
+    public static List<String> getModPacksWithVanilla()
+    {
+        List<String> modpacks = getModPacks();
+        modpacks.add("vanilla");
+        return modpacks;
+    }
 }

src/main/java/net/minecraftforge/common/Tags.java

@@ -34,8 +34,16 @@ import net.minecraftforge.registries.IForgeRegistryEntry;
 
 public class Tags
 {
+    public static void init ()
+    {
+        Blocks.init();
+        Items.init();
+    }
+
     public static class Blocks
     {
+        private static void init(){}
+
         public static final ITag.INamedTag<Block> CHESTS = tag("chests");
         public static final ITag.INamedTag<Block> CHESTS_ENDER = tag("chests/ender");
         public static final ITag.INamedTag<Block> CHESTS_TRAPPED = tag("chests/trapped");
@@ -132,6 +140,8 @@ public class Tags
 
     public static class Items
     {
+        private static void init(){}
+
         public static final ITag.INamedTag<Item> ARROWS = tag("arrows");
         public static final ITag.INamedTag<Item> BONES = tag("bones");
         public static final ITag.INamedTag<Item> BOOKSHELVES = tag("bookshelves");

src/main/java/net/minecraftforge/fml/packs/ResourcePackLoader.java

@@ -61,6 +61,11 @@ public class ResourcePackLoader
         resourcePacks.addPackFinder(new LambdaFriendlyPackFinder(packFinder.apply(modResourcePacks, ModFileResourcePack::setPackInfo)));
     }
 
+    public static List<String> getPackNames()
+    {
+        return modResourcePacks.values().stream().map(pack -> pack.getPackInfo().getName()).collect(Collectors.toList());
+    }
+
     public static <V> Comparator<Map.Entry<String,V>> getSorter() {
         List<String> order = new ArrayList<>();
         order.add("vanilla");

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

@@ -52,6 +52,7 @@ import net.minecraft.world.gen.foliageplacer.FoliagePlacerType;
 import net.minecraft.world.gen.placement.Placement;
 import net.minecraft.world.gen.surfacebuilders.SurfaceBuilder;
 import net.minecraft.world.gen.treedecorator.TreeDecoratorType;
+import net.minecraftforge.common.Tags;
 import net.minecraftforge.common.loot.GlobalLootModifierSerializer;
 import net.minecraftforge.fml.common.registry.GameRegistry;
 
@@ -114,5 +115,6 @@ public class ForgeRegistries
     {
         GameData.init();
         Bootstrap.register();
+        Tags.init();
     }
 }