Make /locate command support modded structures

patches/minecraft/net/minecraft/command/impl/LocateCommand.java.patch

@@ -0,0 +1,17 @@
+--- a/net/minecraft/command/impl/LocateCommand.java
++++ b/net/minecraft/command/impl/LocateCommand.java
+@@ -20,6 +20,14 @@
+    public static void func_198528_a(CommandDispatcher<CommandSource> p_198528_0_) {
+       p_198528_0_.register(Commands.func_197057_a("locate").requires((p_198533_0_) -> {
+          return p_198533_0_.func_197034_c(2);
++      }).then(Commands.func_197056_a("structure_type", net.minecraftforge.common.command.StructureArgument.structure())
++              .suggests(net.minecraftforge.common.command.StructureArgument.suggestions())
++              .executes(ctx -> {
++                  return func_198534_a(ctx.getSource(), ctx.getArgument("structure_type", net.minecraft.util.ResourceLocation.class).toString().replace("minecraft:", ""));
++      })));
++      if (true) return; // Forge: replace this code with above extensible version
++      p_198528_0_.register(Commands.func_197057_a("locate").requires((p_198533_0_) -> {
++         return p_198533_0_.func_197034_c(2);
+       }).then(Commands.func_197057_a("Pillager_Outpost").executes((p_198530_0_) -> {
+          return func_198534_a(p_198530_0_.getSource(), "Pillager_Outpost");
+       })).then(Commands.func_197057_a("Mineshaft").executes((p_198535_0_) -> {

src/main/java/net/minecraftforge/common/command/StructureArgument.java

@@ -0,0 +1,93 @@
+package net.minecraftforge.common.command;
+
+import com.google.common.collect.Streams;
+import com.mojang.brigadier.StringReader;
+import com.mojang.brigadier.arguments.ArgumentType;
+import com.mojang.brigadier.context.CommandContext;
+import com.mojang.brigadier.exceptions.CommandSyntaxException;
+import com.mojang.brigadier.exceptions.DynamicCommandExceptionType;
+import com.mojang.brigadier.exceptions.SimpleCommandExceptionType;
+import com.mojang.brigadier.suggestion.SuggestionProvider;
+
+import net.minecraft.command.CommandSource;
+import net.minecraft.command.ISuggestionProvider;
+import net.minecraft.util.ResourceLocation;
+import net.minecraft.util.ResourceLocationException;
+import net.minecraft.util.text.TranslationTextComponent;
+import net.minecraft.world.gen.feature.structure.Structure;
+import net.minecraftforge.registries.GameData;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Locale;
+
+public class StructureArgument implements ArgumentType<ResourceLocation>
+{
+    private static final Collection<String> EXAMPLES = Arrays.asList("minecraft:village", "Mansion");
+    public static final DynamicCommandExceptionType STRUCTURE_UNKNOWN_TYPE = new DynamicCommandExceptionType((p_211367_0_) ->
+    {
+        return new TranslationTextComponent("structure.notFound", p_211367_0_);
+    });
+
+    public static StructureArgument structure()
+    {
+        return new StructureArgument();
+    }
+
+    public static SuggestionProvider<CommandSource> suggestions()
+    {
+        return (ctx, sb) -> ISuggestionProvider.suggest(Streams.concat(
+                GameData.getStructureMap().values().stream().map(Structure::getStructureName),
+                GameData.getStructureFeatures().keySet().stream().map(ResourceLocation::toString)), sb);
+    }
+
+    public static ResourceLocation getStructureId(CommandContext<CommandSource> context, String name) throws CommandSyntaxException
+    {
+        return checkIfStructureExists(context.getArgument(name, ResourceLocation.class));
+    }
+
+    private static ResourceLocation checkIfStructureExists(ResourceLocation id) throws CommandSyntaxException
+    {
+        if (id.getNamespace().equals("minecraft"))
+        {
+            // Special case vanilla hardcoded names, for vanilla compat
+            Structure<?> structure = GameData.getStructureMap().values().stream()
+                    .filter(s -> s.getStructureName().equalsIgnoreCase(id.getPath()))
+                    .findFirst()
+                    .orElse(null);
+            if (structure != null)
+                return id;
+        }
+        GameData.getStructureFeatures().getValue(id).orElseThrow(() -> STRUCTURE_UNKNOWN_TYPE.create(id));
+        return id;
+    }
+    
+    private static final SimpleCommandExceptionType INVALID_EXCEPTION = new SimpleCommandExceptionType(new TranslationTextComponent("argument.id.invalid"));
+
+    public ResourceLocation parse(StringReader reader) throws CommandSyntaxException
+    {
+        // Logic taken from ResourceLocation.read, but made case-insensitive
+        int cursor = reader.getCursor();
+        try
+        {
+            while (reader.canRead() && ResourceLocation.isValidPathCharacter(Character.toLowerCase(reader.peek())))
+            {
+                reader.skip();
+            }
+
+            String s = reader.getString().substring(cursor, reader.getCursor());
+            ResourceLocation rl = new ResourceLocation(s.toLowerCase(Locale.ROOT));
+            return checkIfStructureExists(rl);
+        }
+        catch (ResourceLocationException e)
+        {
+            reader.setCursor(cursor);
+            throw INVALID_EXCEPTION.createWithContext(reader);
+        }
+    }
+
+    public Collection<String> getExamples()
+    {
+        return EXAMPLES;
+    }
+}

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

@@ -198,7 +198,7 @@ public class GameData
         // Worldgen
         makeRegistry(WORLD_CARVERS, WorldCarver.class).disableSaving().disableSync().create();
         makeRegistry(SURFACE_BUILDERS, SurfaceBuilder.class).disableSaving().disableSync().create();
-        makeRegistry(FEATURES, Feature.class).addCallback(FeatureCallbacks.INSTANCE).disableSaving().disableSync().create();
+        makeRegistry(FEATURES, Feature.class).addCallback(FeatureCallbacks.INSTANCE).disableSaving().create();
         makeRegistry(DECORATORS, Placement.class).disableSaving().disableSync().create();
         makeRegistry(BIOME_PROVIDER_TYPES, BiomeProviderType.class).disableSaving().disableSync().create();
         makeRegistry(CHUNK_GENERATOR_TYPES, ChunkGeneratorType.class).disableSaving().disableSync().create();

src/main/resources/assets/forge/lang/en_us.json

@@ -72,6 +72,8 @@
   "fml.messages.version.restriction.bounded.lowerexclusive":"above {0}, and {1} or below",
   "fml.messages.version.restriction.bounded.upperexclusive":"{0} or above, and below {1}",
 
+  "structure.notFound": "Unknown structure: %s",
+
   "commands.forge.dimensions.list": "Currently registered dimensions by type:",
   "commands.forge.entity.list.invalid": "Invalid filter, does not match any entities. Use /forge entity list for a proper list",
   "commands.forge.entity.list.invalidworld": "Could not load world for dimension {0}. Please select a valid dimension.",