Add AccessWidenerValidator (#518)

* Add AccessWidenerValidator

* Move to task

* Review feedback

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));
+			}
+		}
+	}
+}