Intermediate mapping handling improvements. (#593)

* Add API for intermediate mappings. Add hacky option to run with no intermediate mappings.

* Add setter, and some getters that I need :)

* Remove unused inject.

* Don't add asm-all to the libraries.

* Fix unit tests.

src/main/java/net/fabricmc/loom/LoomGradleExtension.java

@@ -112,10 +112,6 @@ public interface LoomGradleExtension extends LoomGradleExtensionAPI {
 
 	boolean isRootProject();
 
-	default String getIntermediaryUrl(String minecraftVersion) {
-		return String.format(this.getIntermediaryUrl().get(), minecraftVersion);
-	}
-
 	@Override
 	MixinExtension getMixin();
 

src/main/java/net/fabricmc/loom/api/LoomGradleExtensionAPI.java

@@ -35,9 +35,11 @@ import org.gradle.api.publish.maven.MavenPublication;
 import org.jetbrains.annotations.ApiStatus;
 
 import net.fabricmc.loom.api.decompilers.DecompilerOptions;
+import net.fabricmc.loom.api.mappings.intermediate.IntermediateMappingsProvider;
 import net.fabricmc.loom.api.mappings.layered.spec.LayeredMappingSpecBuilder;
 import net.fabricmc.loom.configuration.ide.RunConfigSettings;
 import net.fabricmc.loom.configuration.processors.JarProcessor;
+import net.fabricmc.loom.configuration.providers.mappings.NoOpIntermediateMappingsProvider;
 import net.fabricmc.loom.configuration.providers.minecraft.MinecraftJarConfiguration;
 import net.fabricmc.loom.util.DeprecationHelper;
 
@@ -130,6 +132,23 @@ public interface LoomGradleExtensionAPI {
 	 */
 	Property<Boolean> getEnableTransitiveAccessWideners();
 
+	@ApiStatus.Experimental
+	IntermediateMappingsProvider getIntermediateMappingsProvider();
+
+	@ApiStatus.Experimental
+	void setIntermediateMappingsProvider(IntermediateMappingsProvider intermediateMappingsProvider);
+
+	@ApiStatus.Experimental
+	<T extends IntermediateMappingsProvider> void setIntermediateMappingsProvider(Class<T> clazz, Action<T> action);
+
+	/**
+	 * An Experimental option to provide empty intermediate mappings, to be used for game versions without any intermediate mappings.
+	 */
+	@ApiStatus.Experimental
+	default void noIntermediateMappings() {
+		setIntermediateMappingsProvider(NoOpIntermediateMappingsProvider.class, p -> { });
+	}
+
 	/**
 	 * Use "%1$s" as a placeholder for the minecraft version.
 	 *

src/main/java/net/fabricmc/loom/api/mappings/intermediate/IntermediateMappingsProvider.java

@@ -0,0 +1,47 @@
+/*
+ * This file is part of fabric-loom, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) 2022 FabricMC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package net.fabricmc.loom.api.mappings.intermediate;
+
+import java.io.IOException;
+import java.nio.file.Path;
+
+import org.gradle.api.Named;
+import org.gradle.api.provider.Property;
+import org.jetbrains.annotations.ApiStatus;
+
+/**
+ * A simple API to allow 3rd party plugins.
+ * Implement by creating an abstract class overriding provide and getName
+ */
+@ApiStatus.Experimental
+public abstract class IntermediateMappingsProvider implements Named {
+	public abstract Property<String> getMinecraftVersion();
+
+	/**
+	 * Generate or download a tinyv2 mapping file with intermediary and named namespaces.
+	 * @throws IOException
+	 */
+	public abstract void provide(Path tinyMappings) throws IOException;
+}

src/main/java/net/fabricmc/loom/configuration/providers/mappings/GradleMappingContext.java

@@ -65,7 +65,7 @@ public class GradleMappingContext implements MappingContext {
 
 	@Override
 	public Supplier<MemoryMappingTree> intermediaryTree() {
-		return () -> IntermediaryService.getInstance(project, minecraftProvider()).getMemoryMappingTree();
+		return () -> IntermediateMappingsService.getInstance(project, minecraftProvider()).getMemoryMappingTree();
 	}
 
 	@Override
@@ -82,4 +82,12 @@ public class GradleMappingContext implements MappingContext {
 	public Logger getLogger() {
 		return project.getLogger();
 	}
+
+	public Project getProject() {
+		return project;
+	}
+
+	public LoomGradleExtension getExtension() {
+		return extension;
+	}
 }

src/main/java/net/fabricmc/loom/configuration/providers/mappings/IntermediaryMappingsProvider.java

@@ -0,0 +1,71 @@
+/*
+ * This file is part of fabric-loom, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) 2022 FabricMC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package net.fabricmc.loom.configuration.providers.mappings;
+
+import java.io.IOException;
+import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import com.google.common.net.UrlEscapers;
+import org.gradle.api.provider.Property;
+import org.jetbrains.annotations.NotNull;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import net.fabricmc.loom.LoomGradlePlugin;
+import net.fabricmc.loom.api.mappings.intermediate.IntermediateMappingsProvider;
+import net.fabricmc.loom.util.DownloadUtil;
+
+public abstract class IntermediaryMappingsProvider extends IntermediateMappingsProvider {
+	private static final Logger LOGGER = LoggerFactory.getLogger(IntermediateMappingsProvider.class);
+
+	public abstract Property<String> getIntermediaryUrl();
+
+	@Override
+	public void provide(Path tinyMappings) throws IOException {
+		if (Files.exists(tinyMappings) && !LoomGradlePlugin.refreshDeps) {
+			return;
+		}
+
+		// Download and extract intermediary
+		final Path intermediaryJarPath = Files.createTempFile(getName(), ".jar");
+		final String encodedMcVersion = UrlEscapers.urlFragmentEscaper().escape(getMinecraftVersion().get());
+		final URL url = new URL(getIntermediaryUrl().get().formatted(encodedMcVersion));
+
+		LOGGER.info("Downloading intermediary from {}", url);
+
+		Files.deleteIfExists(tinyMappings);
+		Files.deleteIfExists(intermediaryJarPath);
+
+		DownloadUtil.downloadIfChanged(url, intermediaryJarPath.toFile(), LOGGER);
+		MappingsProviderImpl.extractMappings(intermediaryJarPath, tinyMappings);
+	}
+
+	@Override
+	public @NotNull String getName() {
+		return "intermediary-v2";
+	}
+}

src/main/java/net/fabricmc/loom/configuration/providers/mappings/IntermediateMappingsService.java

@@ -25,10 +25,8 @@
 package net.fabricmc.loom.configuration.providers.mappings;
 
 import java.io.BufferedReader;
-import java.io.File;
 import java.io.IOException;
 import java.io.UncheckedIOException;
-import java.net.URL;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -37,59 +35,52 @@ import java.util.Objects;
 import java.util.function.Supplier;
 
 import com.google.common.base.Suppliers;
-import com.google.common.net.UrlEscapers;
 import org.gradle.api.Project;
 import org.jetbrains.annotations.VisibleForTesting;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import net.fabricmc.loom.LoomGradleExtension;
-import net.fabricmc.loom.LoomGradlePlugin;
+import net.fabricmc.loom.api.mappings.intermediate.IntermediateMappingsProvider;
 import net.fabricmc.loom.api.mappings.layered.MappingsNamespace;
 import net.fabricmc.loom.configuration.providers.minecraft.MinecraftProvider;
-import net.fabricmc.loom.util.DownloadUtil;
 import net.fabricmc.loom.util.service.SharedService;
 import net.fabricmc.loom.util.service.SharedServiceManager;
 import net.fabricmc.mappingio.adapter.MappingNsCompleter;
 import net.fabricmc.mappingio.format.Tiny2Reader;
 import net.fabricmc.mappingio.tree.MemoryMappingTree;
 
-public final class IntermediaryService implements SharedService {
-	private static final Logger LOGGER = LoggerFactory.getLogger(IntermediaryService.class);
-
+public final class IntermediateMappingsService implements SharedService {
 	private final Path intermediaryTiny;
 	private final Supplier<MemoryMappingTree> memoryMappingTree = Suppliers.memoize(this::createMemoryMappingTree);
 
-	private IntermediaryService(Path intermediaryTiny) {
+	private IntermediateMappingsService(Path intermediaryTiny) {
 		this.intermediaryTiny = intermediaryTiny;
 	}
 
-	public static synchronized IntermediaryService getInstance(Project project, MinecraftProvider minecraftProvider) {
+	public static synchronized IntermediateMappingsService getInstance(Project project, MinecraftProvider minecraftProvider) {
 		final LoomGradleExtension extension = LoomGradleExtension.get(project);
-		final String encodedMinecraftVersion = UrlEscapers.urlFragmentEscaper().escape(minecraftProvider.minecraftVersion());
-		final String intermediaryArtifactUrl = extension.getIntermediaryUrl(encodedMinecraftVersion);
+		final IntermediateMappingsProvider intermediateProvider = extension.getIntermediateMappingsProvider();
+		final String id = "IntermediateMappingsService:%s:%s".formatted(intermediateProvider.getName(), intermediateProvider.getMinecraftVersion().get());
 
-		return SharedServiceManager.get(project).getOrCreateService("IntermediaryService:" + intermediaryArtifactUrl,
-				() -> create(intermediaryArtifactUrl, minecraftProvider));
+		return SharedServiceManager.get(project).getOrCreateService(id, () -> create(intermediateProvider, minecraftProvider));
 	}
 
 	@VisibleForTesting
-	public static IntermediaryService create(String intermediaryUrl, MinecraftProvider minecraftProvider) {
-		final Path intermediaryTiny = minecraftProvider.file("intermediary-v2.tiny").toPath();
-
-		if (!Files.exists(intermediaryTiny) || LoomGradlePlugin.refreshDeps) {
-			// Download and extract intermediary
-			File intermediaryJar = minecraftProvider.file("intermediary-v2.jar");
+	public static IntermediateMappingsService create(IntermediateMappingsProvider intermediateMappingsProvider, MinecraftProvider minecraftProvider) {
+		final Path intermediaryTiny = minecraftProvider.file(intermediateMappingsProvider.getName() + ".tiny").toPath();
 
+		try {
+			intermediateMappingsProvider.provide(intermediaryTiny);
+		} catch (IOException e) {
 			try {
-				DownloadUtil.downloadIfChanged(new URL(intermediaryUrl), intermediaryJar, LOGGER);
-				MappingsProviderImpl.extractMappings(intermediaryJar.toPath(), intermediaryTiny);
-			} catch (IOException e) {
-				throw new UncheckedIOException("Failed to download and extract intermediary", e);
+				Files.deleteIfExists(intermediaryTiny);
+			} catch (IOException ex) {
+				ex.printStackTrace();
 			}
+
+			throw new UncheckedIOException("Failed to provide intermediate mappings", e);
 		}
 
-		return new IntermediaryService(intermediaryTiny);
+		return new IntermediateMappingsService(intermediaryTiny);
 	}
 
 	private MemoryMappingTree createMemoryMappingTree() {

src/main/java/net/fabricmc/loom/configuration/providers/mappings/MappingsProviderImpl.java

@@ -83,9 +83,9 @@ public class MappingsProviderImpl implements MappingsProvider, SharedService {
 	private UnpickMetadata unpickMetadata;
 	private Map<String, String> signatureFixes;
 
-	private final Supplier<IntermediaryService> intermediaryService;
+	private final Supplier<IntermediateMappingsService> intermediaryService;
 
-	private MappingsProviderImpl(String mappingsIdentifier, Path mappingsWorkingDir, Supplier<IntermediaryService> intermediaryService) {
+	private MappingsProviderImpl(String mappingsIdentifier, Path mappingsWorkingDir, Supplier<IntermediateMappingsService> intermediaryService) {
 		this.mappingsIdentifier = mappingsIdentifier;
 
 		this.mappingsWorkingDir = mappingsWorkingDir;
@@ -99,7 +99,7 @@ public class MappingsProviderImpl implements MappingsProvider, SharedService {
 
 	public static synchronized MappingsProviderImpl getInstance(Project project, DependencyInfo dependency, MinecraftProvider minecraftProvider) {
 		return SharedServiceManager.get(project).getOrCreateService("MappingsProvider:%s:%s".formatted(dependency.getDepString(), minecraftProvider.minecraftVersion()), () -> {
-			Supplier<IntermediaryService> intermediaryService = Suppliers.memoize(() -> IntermediaryService.getInstance(project, minecraftProvider));
+			Supplier<IntermediateMappingsService> intermediaryService = Suppliers.memoize(() -> IntermediateMappingsService.getInstance(project, minecraftProvider));
 			return create(dependency, minecraftProvider, intermediaryService);
 		});
 	}
@@ -108,7 +108,7 @@ public class MappingsProviderImpl implements MappingsProvider, SharedService {
 		return Objects.requireNonNull(mappingTree, "Cannot get mappings before they have been read").get();
 	}
 
-	private static MappingsProviderImpl create(DependencyInfo dependency, MinecraftProvider minecraftProvider, Supplier<IntermediaryService> intermediaryService) {
+	private static MappingsProviderImpl create(DependencyInfo dependency, MinecraftProvider minecraftProvider, Supplier<IntermediateMappingsService> intermediaryService) {
 		final String version = dependency.getResolvedVersion();
 		final Path inputJar = dependency.resolveFile().orElseThrow(() -> new RuntimeException("Could not resolve mappings: " + dependency)).toPath();
 		final String mappingsName = StringUtils.removeSuffix(dependency.getDependency().getGroup() + "." + dependency.getDependency().getName(), "-unmerged");

src/main/java/net/fabricmc/loom/configuration/providers/mappings/NoOpIntermediateMappingsProvider.java

@@ -0,0 +1,51 @@
+/*
+ * This file is part of fabric-loom, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) 2022 FabricMC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package net.fabricmc.loom.configuration.providers.mappings;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import org.jetbrains.annotations.NotNull;
+
+import net.fabricmc.loom.api.mappings.intermediate.IntermediateMappingsProvider;
+
+/**
+ * A bit of a hack, creates an empty intermediary mapping file to be used for mc versions without any intermediate mappings.
+ */
+public abstract class NoOpIntermediateMappingsProvider extends IntermediateMappingsProvider {
+	private static final String HEADER = "tiny\t2\t0\tofficial\tintermediary";
+
+	@Override
+	public void provide(Path tinyMappings) throws IOException {
+		Files.writeString(tinyMappings, HEADER, StandardCharsets.UTF_8);
+	}
+
+	@Override
+	public @NotNull String getName() {
+		return "empty-intermediate";
+	}
+}

src/main/java/net/fabricmc/loom/configuration/providers/mappings/tiny/MappingsMerger.java

@@ -38,7 +38,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import net.fabricmc.loom.api.mappings.layered.MappingsNamespace;
-import net.fabricmc.loom.configuration.providers.mappings.IntermediaryService;
+import net.fabricmc.loom.configuration.providers.mappings.IntermediateMappingsService;
 import net.fabricmc.mappingio.adapter.MappingNsCompleter;
 import net.fabricmc.mappingio.adapter.MappingSourceNsSwitch;
 import net.fabricmc.mappingio.format.Tiny2Reader;
@@ -49,12 +49,12 @@ import net.fabricmc.mappingio.tree.MemoryMappingTree;
 public final class MappingsMerger {
 	private static final Logger LOGGER = LoggerFactory.getLogger(MappingsMerger.class);
 
-	public static void mergeAndSaveMappings(Path from, Path out, IntermediaryService intermediaryService) throws IOException {
+	public static void mergeAndSaveMappings(Path from, Path out, IntermediateMappingsService intermediateMappingsService) throws IOException {
 		Stopwatch stopwatch = Stopwatch.createStarted();
 		LOGGER.info(":merging mappings");
 
 		MemoryMappingTree intermediaryTree = new MemoryMappingTree();
-		intermediaryService.getMemoryMappingTree().accept(new MappingSourceNsSwitch(intermediaryTree, MappingsNamespace.INTERMEDIARY.toString()));
+		intermediateMappingsService.getMemoryMappingTree().accept(new MappingSourceNsSwitch(intermediaryTree, MappingsNamespace.INTERMEDIARY.toString()));
 
 		try (BufferedReader reader = Files.newBufferedReader(from, StandardCharsets.UTF_8)) {
 			Tiny2Reader.read(reader, intermediaryTree);

src/main/java/net/fabricmc/loom/configuration/providers/minecraft/MinecraftLibraryProvider.java

@@ -62,6 +62,9 @@ public class MinecraftLibraryProvider {
 				// 1.4.7 contains an LWJGL version with an invalid maven pom, set the metadata sources to not use the pom for this version.
 				if ("org.lwjgl.lwjgl:lwjgl:2.9.1-nightly-20130708-debug3".equals(library.name())) {
 					LoomRepositoryPlugin.setupForLegacyVersions(project);
+				} else if (library.name().startsWith("org.ow2.asm:asm-all")) {
+					// Don't want asm-all, use the modern split version.
+					continue;
 				}
 
 				if (runtimeOnlyLog4j && library.name().startsWith("org.apache.logging.log4j")) {

src/main/java/net/fabricmc/loom/extension/LoomGradleExtensionApiImpl.java

@@ -40,6 +40,7 @@ import net.fabricmc.loom.api.InterfaceInjectionExtensionAPI;
 import net.fabricmc.loom.api.LoomGradleExtensionAPI;
 import net.fabricmc.loom.api.MixinExtensionAPI;
 import net.fabricmc.loom.api.decompilers.DecompilerOptions;
+import net.fabricmc.loom.api.mappings.intermediate.IntermediateMappingsProvider;
 import net.fabricmc.loom.api.mappings.layered.spec.LayeredMappingSpecBuilder;
 import net.fabricmc.loom.configuration.ide.RunConfigSettings;
 import net.fabricmc.loom.configuration.mods.ModVersionParser;
@@ -65,6 +66,7 @@ public abstract class LoomGradleExtensionApiImpl implements LoomGradleExtensionA
 	protected final Property<Boolean> setupRemappedVariants;
 	protected final Property<Boolean> transitiveAccessWideners;
 	protected final Property<String> intermediary;
+	protected final Property<IntermediateMappingsProvider> intermediateMappingsProvider;
 	private final Property<Boolean> runtimeOnlyLog4j;
 	private final Property<MinecraftJarConfiguration> minecraftJarConfiguration;
 	private final InterfaceInjectionExtensionAPI interfaceInjectionExtension;
@@ -92,6 +94,9 @@ public abstract class LoomGradleExtensionApiImpl implements LoomGradleExtensionA
 		this.intermediary = project.getObjects().property(String.class)
 				.convention("https://maven.fabricmc.net/net/fabricmc/intermediary/%1$s/intermediary-%1$s-v2.jar");
 
+		this.intermediateMappingsProvider = project.getObjects().property(IntermediateMappingsProvider.class);
+		this.intermediateMappingsProvider.finalizeValueOnRead();
+
 		this.versionParser = new ModVersionParser(project);
 
 		this.deprecationHelper = new DeprecationHelper.ProjectBased(project);
@@ -214,6 +219,26 @@ public abstract class LoomGradleExtensionApiImpl implements LoomGradleExtensionA
 		return intermediary;
 	}
 
+	@Override
+	public IntermediateMappingsProvider getIntermediateMappingsProvider() {
+		return intermediateMappingsProvider.get();
+	}
+
+	@Override
+	public void setIntermediateMappingsProvider(IntermediateMappingsProvider intermediateMappingsProvider) {
+		this.intermediateMappingsProvider.set(intermediateMappingsProvider);
+	}
+
+	@Override
+	public <T extends IntermediateMappingsProvider> void setIntermediateMappingsProvider(Class<T> clazz, Action<T> action) {
+		T provider = getProject().getObjects().newInstance(clazz);
+		configureIntermediateMappingsProviderInternal(provider);
+		action.execute(provider);
+		intermediateMappingsProvider.set(provider);
+	}
+
+	protected abstract <T extends IntermediateMappingsProvider> void configureIntermediateMappingsProviderInternal(T provider);
+
 	@Override
 	public void disableDeprecatedPomGeneration(MavenPublication publication) {
 		net.fabricmc.loom.configuration.MavenPublication.excludePublication(publication);
@@ -256,6 +281,11 @@ public abstract class LoomGradleExtensionApiImpl implements LoomGradleExtensionA
 			throw new RuntimeException("Yeah... something is really wrong");
 		}
 
+		@Override
+		protected <T extends IntermediateMappingsProvider> void configureIntermediateMappingsProviderInternal(T provider) {
+			throw new RuntimeException("Yeah... something is really wrong");
+		}
+
 		@Override
 		public MixinExtension getMixin() {
 			throw new RuntimeException("Yeah... something is really wrong");

src/main/java/net/fabricmc/loom/extension/LoomGradleExtensionImpl.java

@@ -42,11 +42,13 @@ import org.gradle.api.file.ConfigurableFileCollection;
 import org.gradle.api.file.FileCollection;
 
 import net.fabricmc.loom.LoomGradleExtension;
+import net.fabricmc.loom.api.mappings.intermediate.IntermediateMappingsProvider;
 import net.fabricmc.loom.api.mappings.layered.MappingsNamespace;
 import net.fabricmc.loom.configuration.InstallerData;
 import net.fabricmc.loom.configuration.LoomDependencyManager;
 import net.fabricmc.loom.configuration.accesswidener.AccessWidenerFile;
 import net.fabricmc.loom.configuration.processors.JarProcessorManager;
+import net.fabricmc.loom.configuration.providers.mappings.IntermediaryMappingsProvider;
 import net.fabricmc.loom.configuration.providers.mappings.MappingsProviderImpl;
 import net.fabricmc.loom.configuration.providers.minecraft.MinecraftProvider;
 import net.fabricmc.loom.configuration.providers.minecraft.mapped.IntermediaryMinecraftProvider;
@@ -78,6 +80,13 @@ public class LoomGradleExtensionImpl extends LoomGradleExtensionApiImpl implemen
 		this.mixinApExtension = project.getObjects().newInstance(MixinExtensionImpl.class, project);
 		this.loomFiles = files;
 		this.unmappedMods = project.files();
+
+		// Setup the default intermediate mappings provider.
+		setIntermediateMappingsProvider(IntermediaryMappingsProvider.class, provider -> {
+			provider.getIntermediaryUrl()
+					.convention(getIntermediaryUrl())
+					.finalizeValueOnRead();
+		});
 	}
 
 	@Override
@@ -226,4 +235,10 @@ public class LoomGradleExtensionImpl extends LoomGradleExtensionApiImpl implemen
 	public void addTransitiveAccessWideners(List<AccessWidenerFile> accessWidenerFiles) {
 		transitiveAccessWideners.addAll(accessWidenerFiles);
 	}
+
+	@Override
+	protected <T extends IntermediateMappingsProvider> void configureIntermediateMappingsProviderInternal(T provider) {
+		provider.getMinecraftVersion().set(getProject().provider(() -> getMinecraftProvider().minecraftVersion()));
+		provider.getMinecraftVersion().disallowChanges();
+	}
 }