Add a method to data generator entrypoints to register custom keys wi…

…th priorities (#3087)

* Add JsonKeySortOrderCallback

* Use an entry point rather than an event for sort keys and priorities

* Resolve static imports

* Add a bit of javadoc

* Check if a key is null and modify the javadoc

* Add a field reference in the javadoc

* Rename JsonKeySortOrderAdder to JsonKeySortOrderCallback

fabric-data-generation-api-v1/src/main/java/net/fabricmc/fabric/api/datagen/v1/DataGeneratorEntrypoint.java

@@ -60,4 +60,11 @@ default String getEffectiveModId() {
 	 */
 	default void buildRegistry(RegistryBuilder registryBuilder) {
 	}
+
+	/**
+	 * Provides a callback for setting the sort priority of object keys in generated JSON files.
+	 * @param callback a callback for setting the sort priority for a given key
+	 */
+	default void addJsonKeySortOrders(JsonKeySortOrderCallback callback) {
+	}
 }

fabric-data-generation-api-v1/src/main/java/net/fabricmc/fabric/api/datagen/v1/JsonKeySortOrderCallback.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.fabric.api.datagen.v1;
+
+/**
+ * Provides a callback for setting the sort priority of object keys in generated JSON files.
+ */
+@FunctionalInterface
+public interface JsonKeySortOrderCallback {
+	/**
+	 * Sets the sort priority for a given object key within generated JSON files.
+	 * @param key the key to set priority for
+	 * @param priority the priority for the key, where keys with lower priority are sorted before keys with higher priority
+	 * @implNote The default priority is 2.
+	 * @see net.minecraft.data.DataProvider#JSON_KEY_SORT_ORDER
+	 */
+	void add(String key, int priority);
+}

fabric-data-generation-api-v1/src/main/java/net/fabricmc/fabric/impl/datagen/FabricDataGenHelper.java

@@ -20,6 +20,7 @@
 import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.IdentityHashMap;
 import java.util.List;
 import java.util.Map;
@@ -28,11 +29,13 @@
 
 import com.mojang.logging.LogUtils;
 import com.mojang.serialization.Lifecycle;
+import it.unimi.dsi.fastutil.objects.Object2IntOpenHashMap;
 import org.apache.commons.lang3.ArrayUtils;
 import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import net.minecraft.data.DataProvider;
 import net.minecraft.registry.BuiltinRegistries;
 import net.minecraft.registry.DynamicRegistryManager;
 import net.minecraft.registry.Registerable;
@@ -107,6 +110,9 @@ private static void runInternal() {
 		final List<DataGeneratorEntrypoint> entrypoints = dataGeneratorInitializers.stream().map(EntrypointContainer::getEntrypoint).toList();
 		CompletableFuture<RegistryWrapper.WrapperLookup> registriesFuture = CompletableFuture.supplyAsync(() -> createRegistryWrapper(entrypoints), Util.getMainWorkerExecutor());
 
+		Object2IntOpenHashMap<String> jsonKeySortOrders = (Object2IntOpenHashMap<String>) DataProvider.JSON_KEY_SORT_ORDER;
+		Object2IntOpenHashMap<String> defaultJsonKeySortOrders = new Object2IntOpenHashMap<>(jsonKeySortOrders);
+
 		for (EntrypointContainer<DataGeneratorEntrypoint> entrypointContainer : dataGeneratorInitializers) {
 			final String id = entrypointContainer.getProvider().getMetadata().getId();
 
@@ -123,13 +129,23 @@ private static void runInternal() {
 				final String effectiveModId = entrypoint.getEffectiveModId();
 				ModContainer modContainer = entrypointContainer.getProvider();
 
+				HashSet<String> keys = new HashSet<>();
+				entrypoint.addJsonKeySortOrders((key, value) -> {
+					Objects.requireNonNull(key, "Tried to register a priority for a null key");
+					jsonKeySortOrders.put(key, value);
+					keys.add(key);
+				});
+
 				if (effectiveModId != null) {
 					modContainer = FabricLoader.getInstance().getModContainer(effectiveModId).orElseThrow(() -> new RuntimeException("Failed to find effective mod container for mod id (%s)".formatted(effectiveModId)));
 				}
 
 				FabricDataGenerator dataGenerator = new FabricDataGenerator(outputDir, modContainer, STRICT_VALIDATION, registriesFuture);
 				entrypoint.onInitializeDataGenerator(dataGenerator);
 				dataGenerator.run();
+
+				jsonKeySortOrders.keySet().removeAll(keys);
+				jsonKeySortOrders.putAll(defaultJsonKeySortOrders);
 			} catch (Throwable t) {
 				throw new RuntimeException("Failed to run data generator from mod (%s)".formatted(id), t);
 			}

fabric-data-generation-api-v1/src/testmod/java/net/fabricmc/fabric/test/datagen/DataGeneratorTestEntrypoint.java

@@ -73,6 +73,7 @@
 import net.fabricmc.fabric.api.datagen.v1.DataGeneratorEntrypoint;
 import net.fabricmc.fabric.api.datagen.v1.FabricDataGenerator;
 import net.fabricmc.fabric.api.datagen.v1.FabricDataOutput;
+import net.fabricmc.fabric.api.datagen.v1.JsonKeySortOrderCallback;
 import net.fabricmc.fabric.api.datagen.v1.provider.FabricAdvancementProvider;
 import net.fabricmc.fabric.api.datagen.v1.provider.FabricBlockLootTableProvider;
 import net.fabricmc.fabric.api.datagen.v1.provider.FabricDynamicRegistryProvider;
@@ -91,6 +92,11 @@ public class DataGeneratorTestEntrypoint implements DataGeneratorEntrypoint {
 	private static final ConditionJsonProvider NEVER_LOADED = DefaultResourceConditions.allModsLoaded("a");
 	private static final ConditionJsonProvider ALWAYS_LOADED = DefaultResourceConditions.not(NEVER_LOADED);
 
+	@Override
+	public void addJsonKeySortOrders(JsonKeySortOrderCallback callback) {
+		callback.add("trigger", 0);
+	}
+
 	@Override
 	public void onInitializeDataGenerator(FabricDataGenerator dataGenerator) {
 		final FabricDataGenerator.Pack pack = dataGenerator.createPack();

fabric-data-generation-api-v1/src/testmodClient/java/net/fabricmc/fabric/test/datagen/client/DataGeneratorClientTestEntrypoint.java

@@ -30,10 +30,16 @@
 import net.fabricmc.fabric.api.datagen.v1.DataGeneratorEntrypoint;
 import net.fabricmc.fabric.api.datagen.v1.FabricDataGenerator;
 import net.fabricmc.fabric.api.datagen.v1.FabricDataOutput;
+import net.fabricmc.fabric.api.datagen.v1.JsonKeySortOrderCallback;
 import net.fabricmc.fabric.api.datagen.v1.provider.FabricCodecDataProvider;
 
 @SuppressWarnings("unused")
 public class DataGeneratorClientTestEntrypoint implements DataGeneratorEntrypoint {
+	@Override
+	public void addJsonKeySortOrders(JsonKeySortOrderCallback callback) {
+		callback.add("type", 100); // Force 'type' at the end
+	}
+
 	@Override
 	public void onInitializeDataGenerator(FabricDataGenerator dataGenerator) {
 		final FabricDataGenerator.Pack pack = dataGenerator.createBuiltinResourcePack(new Identifier(MOD_ID, "example_builtin"));