Allow loading json constants outside of _constants

src/main/java/net/minecraftforge/common/crafting/CraftingHelper.java

@@ -31,6 +31,7 @@ import java.util.stream.Stream;
 import javax.annotation.Nullable;
 
 import net.minecraftforge.fml.ModList;
+
 import com.google.common.collect.BiMap;
 import com.google.common.collect.HashBiMap;
 import com.google.common.collect.Lists;
@@ -303,6 +304,13 @@ public class CraftingHelper
             if (!path.equals("recipes/_constants.json")) //Top level only
                 continue;
             
+            tmp.putAll(loadConstants(manager, key));
+        }
+        constants = tmp;
+    }
+    
+    public static Map<ResourceLocation, IItemList> loadConstants(IResourceManager manager, ResourceLocation key) {
+        Map<ResourceLocation, IItemList> tmp = new HashMap<>();
         try (IResource iresource = manager.getResource(key))
         {
             JsonObject[] elements = JsonUtils.fromJson(GSON, IOUtils.toString(iresource.getInputStream(), StandardCharsets.UTF_8), JsonObject[].class);
@@ -355,7 +363,6 @@ public class CraftingHelper
         {
            LOGGER.error(CRAFTHELPER, "Couldn't read constants from {}", key, e);
         }
-        }
-        constants = tmp;
+        return tmp;
     }
 }

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

@@ -42,7 +42,7 @@ public abstract class ForgeRegistryEntry<V extends IForgeRegistryEntry<V>> imple
         if (getRegistryName() != null)
             throw new IllegalStateException("Attempted to set registry name with existing registry name! New: " + name + " Old: " + getRegistryName());
 
-        this.registryName = GameData.checkPrefix(name);
+        this.registryName = GameData.checkPrefix(name, true);
         return (V)this;
     }
 

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

@@ -896,13 +896,32 @@ public class GameData
         }
     }
 
+    /**
+     * @deprecated Use {@link #checkPrefix(String, boolean)}.
+     */
+    @Deprecated
     public static ResourceLocation checkPrefix(String name)
+    {
+        return checkPrefix(name, true);
+    }
+
+    /**
+     * Check a name for a domain prefix, and if not present infer it from the
+     * current active mod container.
+     * 
+     * @param name          The name or resource location
+     * @param warnOverrides If true, logs a warning if domain differs from that of
+     *                      the currently currently active mod container
+     * 
+     * @return The {@link ResourceLocation} with given or inferred domain
+     */
+    public static ResourceLocation checkPrefix(String name, boolean warnOverrides)
     {
         int index = name.lastIndexOf(':');
         String oldPrefix = index == -1 ? "" : name.substring(0, index).toLowerCase(Locale.ROOT);
         name = index == -1 ? name : name.substring(index + 1);
         String prefix = ModLoadingContext.get().getActiveContainer().getNamespace();
-        if (!oldPrefix.equals(prefix) && oldPrefix.length() > 0)
+        if (warnOverrides && !oldPrefix.equals(prefix) && oldPrefix.length() > 0)
         {
             LogManager.getLogger().info("Potentially Dangerous alternative prefix `{}` for name `{}`, expected `{}`. This could be a intended override, but in most cases indicates a broken mod.", oldPrefix, name, prefix);
             prefix = oldPrefix;

src/test/java/net/minecraftforge/debug/gameplay/ConstantLoadingTest.java

@@ -0,0 +1,62 @@
+/*
+ * Minecraft Forge
+ * Copyright (c) 2016-2018.
+ *
+ * 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.debug.gameplay;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.stream.Stream;
+
+import net.minecraft.init.Items;
+import net.minecraft.item.ItemStack;
+import net.minecraft.item.crafting.Ingredient;
+import net.minecraft.item.crafting.Ingredient.IItemList;
+import net.minecraft.util.ResourceLocation;
+import net.minecraftforge.common.crafting.CraftingHelper;
+import net.minecraftforge.eventbus.api.SubscribeEvent;
+import net.minecraftforge.fml.common.Mod;
+import net.minecraftforge.fml.event.server.FMLServerStartedEvent;
+
+@Mod(ConstantLoadingTest.MODID)
+@Mod.EventBusSubscriber
+public class ConstantLoadingTest
+{
+    public static final String MODID = "constantloadingtest";
+    private static final boolean ENABLED = true;
+
+    @SubscribeEvent
+    public void init(FMLServerStartedEvent event) throws IOException
+    {
+        if (!ENABLED)
+        {
+            return;
+        }
+        
+        Map<ResourceLocation, IItemList> constants = CraftingHelper.loadConstants(event.getServer().getResourceManager(), new ResourceLocation(MODID, "test/_constants.json"));
+        Ingredient flint = Ingredient.fromItemListStream(Stream.of(constants.get(new ResourceLocation("FLINT"))));
+        if (flint == null)
+        {
+            throw new IllegalStateException("Constant ingredient not loaded properly");
+        }
+        if (!flint.test(new ItemStack(Items.FLINT)))
+        {
+            throw new IllegalStateException("Constant ingredient failed to match test input");
+        }
+    }
+}

src/test/resources/assets/constantloadingtest/test/_constants.json

@@ -0,0 +1,8 @@
+[
+  {
+    "ingredient": {
+      "item": "minecraft:flint"
+    },
+    "name": "FLINT"
+  }
+]