Add AccessWidenerValidator (#518)

* Add AccessWidenerValidator

* Move to task

* Review feedback

src/main/java/net/fabricmc/loom/configuration/LoomDependencyManager.java

@@ -39,13 +39,13 @@ import org.gradle.api.artifacts.ExternalModuleDependency;
 import org.gradle.api.artifacts.repositories.MavenArtifactRepository;
 
 import net.fabricmc.loom.LoomGradleExtension;
+import net.fabricmc.loom.LoomRepositoryPlugin;
 import net.fabricmc.loom.build.ModCompileRemapper;
 import net.fabricmc.loom.configuration.DependencyProvider.DependencyInfo;
 import net.fabricmc.loom.configuration.mods.ModProcessor;
 import net.fabricmc.loom.configuration.providers.mappings.MappingsProviderImpl;
 import net.fabricmc.loom.util.Constants;
 import net.fabricmc.loom.util.SourceRemapper;
-import net.fabricmc.loom.LoomRepositoryPlugin;
 
 public class LoomDependencyManager {
 	private static class ProviderList {

src/main/java/net/fabricmc/loom/task/LoomTasks.java

@@ -57,6 +57,13 @@ public final class LoomTasks {
 		tasks.register("downloadAssets", DownloadAssetsTask.class, t -> t.setDescription("Downloads required assets for Fabric."));
 		tasks.register("remapSourcesJar", RemapSourcesJarTask.class, t -> t.setDescription("Remaps the project sources jar to intermediary names."));
 
+		tasks.getByName("check").dependsOn(
+				tasks.register("validateAccessWidener", ValidateAccessWidenerTask.class, t -> {
+					t.setDescription("Validate all the rules in the access widener against the Minecraft jar");
+					t.setGroup("verification");
+				})
+		);
+
 		registerIDETasks(tasks);
 		registerRunTasks(tasks, project);
 		registerDecompileTasks(tasks, project);

src/main/java/net/fabricmc/loom/task/ValidateAccessWidenerTask.java

@@ -0,0 +1,109 @@
+/*
+ * This file is part of fabric-loom, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) 2021 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.task;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+
+import javax.inject.Inject;
+
+import org.gradle.api.DefaultTask;
+import org.gradle.api.file.RegularFileProperty;
+import org.gradle.api.tasks.InputFile;
+import org.gradle.api.tasks.SkipWhenEmpty;
+import org.gradle.api.tasks.TaskAction;
+
+import net.fabricmc.accesswidener.AccessWidenerFormatException;
+import net.fabricmc.accesswidener.AccessWidenerReader;
+import net.fabricmc.accesswidener.AccessWidenerVisitor;
+import net.fabricmc.loom.LoomGradleExtension;
+import net.fabricmc.tinyremapper.TinyRemapper;
+import net.fabricmc.tinyremapper.api.TrEnvironment;
+
+public abstract class ValidateAccessWidenerTask extends DefaultTask {
+	@SkipWhenEmpty
+	@InputFile
+	public abstract RegularFileProperty getAccessWidener();
+
+	@InputFile
+	public abstract RegularFileProperty getTargetJar();
+
+	@Inject
+	public ValidateAccessWidenerTask() {
+		final LoomGradleExtension extension = LoomGradleExtension.get(getProject());
+
+		getAccessWidener().convention(extension.getAccessWidenerPath()).finalizeValueOnRead();
+		getTargetJar().convention(getProject().getObjects().fileProperty().fileValue(extension.getMinecraftMappedProvider().getMappedJar())).finalizeValueOnRead();
+	}
+
+	@TaskAction
+	public void run() {
+		final TinyRemapper tinyRemapper = TinyRemapper.newRemapper().build();
+		tinyRemapper.readClassPath(getTargetJar().get().getAsFile().toPath());
+
+		final AccessWidenerValidator validator = new AccessWidenerValidator(tinyRemapper.getEnvironment());
+		final AccessWidenerReader accessWidenerReader = new AccessWidenerReader(validator);
+
+		try (BufferedReader reader = Files.newBufferedReader(getAccessWidener().get().getAsFile().toPath(), StandardCharsets.UTF_8)) {
+			accessWidenerReader.read(reader, "named");
+		} catch (AccessWidenerFormatException e) {
+			getProject().getLogger().error("Failed to validate access-widener file {} on line {}: {}", getAccessWidener().get().getAsFile().getName(), e.getLineNumber(), e.getMessage());
+			throw e;
+		} catch (IOException e) {
+			throw new UncheckedIOException("Failed to read access widener", e);
+		} finally {
+			tinyRemapper.finish();
+		}
+	}
+
+	/**
+	 * Validates that all entries in an access-widner file relate to a class/method/field in the mc jar.
+	 */
+	private static record AccessWidenerValidator(TrEnvironment environment) implements AccessWidenerVisitor {
+		@Override
+		public void visitClass(String name, AccessWidenerReader.AccessType access, boolean transitive) {
+			if (environment().getClass(name) == null) {
+				throw new RuntimeException("Could not find class (%s)".formatted(name));
+			}
+		}
+
+		@Override
+		public void visitMethod(String owner, String name, String descriptor, AccessWidenerReader.AccessType access, boolean transitive) {
+			if (environment().getMethod(owner, name, descriptor) == null) {
+				throw new RuntimeException("Could not find method (%s%s) in class (%s)".formatted(name, descriptor, owner));
+			}
+		}
+
+		@Override
+		public void visitField(String owner, String name, String descriptor, AccessWidenerReader.AccessType access, boolean transitive) {
+			if (environment().getField(owner, name, descriptor) == null) {
+				throw new RuntimeException("Could not find field (%s%s) in class (%s)".formatted(name, descriptor, owner));
+			}
+		}
+	}
+}

src/test/groovy/net/fabricmc/loom/test/integration/AccessWidenerTest.groovy

@@ -65,4 +65,24 @@ class AccessWidenerTest extends Specification implements GradleProjectTestTrait
 		where:
 			version << STANDARD_TEST_VERSIONS
 	}
+
+	@Unroll
+	def "invalid (#awLine)"() {
+		setup:
+			def gradle = gradleProject(project: "accesswidener", version: version)
+			new File(gradle.projectDir, "src/main/resources/modid.accesswidener").append(awLine)
+			def errorPrefix = "Failed to validate access-widener file modid.accesswidener on line 10: java.lang.RuntimeException: "
+
+		when:
+			def result = gradle.run(task: "check", expectFailure: true)
+
+		then:
+			result.output.contains(errorPrefix + error)
+
+		where:
+			awLine 																					| error																									| version
+			'accessible\tclass\tnet/minecraft/DoesntExists'											| "Could not find class (net/minecraft/DoesntExists)"													| DEFAULT_GRADLE
+			'accessible\tfield\tnet/minecraft/screen/slot/Slot\tabc\tI'								| "Could not find field (abcI) in class (net/minecraft/screen/slot/Slot)"								| DEFAULT_GRADLE
+			'accessible\tmethod\tnet/minecraft/client/main/Main\tmain\t([Ljava/lang/NotAString;)V'	| "Could not find method (main([Ljava/lang/NotAString;)V) in class (net/minecraft/client/main/Main)"	| DEFAULT_GRADLE
+	}
 }

src/test/groovy/net/fabricmc/loom/test/util/GradleProjectTestTrait.groovy

@@ -156,7 +156,7 @@ trait GradleProjectTestTrait {
 
             runner.withArguments(args as String[])
 
-            return runner.build()
+            return options.expectFailure ? runner.buildAndFail() : runner.build()
         }
 
         private GradleRunner getRunner() {