Check that AutoConfiguration classes are listed in imports file

Closes gh-36253

buildSrc/src/main/java/org/springframework/boot/build/architecture/ArchitectureCheck.java

@@ -23,7 +23,6 @@ import java.nio.file.Files;
 import java.nio.file.StandardOpenOption;
 import java.util.List;
 import java.util.stream.Collectors;
-import java.util.stream.Stream;
 
 import com.tngtech.archunit.base.DescribedPredicate;
 import com.tngtech.archunit.core.domain.JavaClass;
@@ -46,9 +45,12 @@ import org.gradle.api.Task;
 import org.gradle.api.file.DirectoryProperty;
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.file.FileTree;
+import org.gradle.api.provider.ListProperty;
 import org.gradle.api.tasks.IgnoreEmptyDirectories;
+import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.InputFiles;
 import org.gradle.api.tasks.Internal;
+import org.gradle.api.tasks.Optional;
 import org.gradle.api.tasks.OutputDirectory;
 import org.gradle.api.tasks.PathSensitive;
 import org.gradle.api.tasks.PathSensitivity;
@@ -66,17 +68,21 @@ public abstract class ArchitectureCheck extends DefaultTask {
 
 	public ArchitectureCheck() {
 		getOutputDirectory().convention(getProject().getLayout().getBuildDirectory().dir(getName()));
+		getRules().addAll(allPackagesShouldBeFreeOfTangles(),
+				allBeanPostProcessorBeanMethodsShouldBeStaticAndHaveParametersThatWillNotCausePrematureInitialization(),
+				allBeanFactoryPostProcessorBeanMethodsShouldBeStaticAndHaveNoParameters(),
+				noClassesShouldCallStepVerifierStepVerifyComplete(),
+				noClassesShouldConfigureDefaultStepVerifierTimeout());
+		getRuleDescriptions()
+			.set(getRules().map((rules) -> rules.stream().map(ArchRule::getDescription).collect(Collectors.toList())));
 	}
 
 	@TaskAction
 	void checkArchitecture() throws IOException {
 		JavaClasses javaClasses = new ClassFileImporter()
 			.importPaths(this.classes.getFiles().stream().map(File::toPath).collect(Collectors.toList()));
-		List<EvaluationResult> violations = Stream.of(allPackagesShouldBeFreeOfTangles(),
-				allBeanPostProcessorBeanMethodsShouldBeStaticAndHaveParametersThatWillNotCausePrematureInitialization(),
-				allBeanFactoryPostProcessorBeanMethodsShouldBeStaticAndHaveNoParameters(),
-				noClassesShouldCallStepVerifierStepVerifyComplete(),
-				noClassesShouldConfigureDefaultStepVerifierTimeout())
+		List<EvaluationResult> violations = getRules().get()
+			.stream()
 			.map((rule) -> rule.evaluate(javaClasses))
 			.filter(EvaluationResult::hasViolation)
 			.collect(Collectors.toList());
@@ -196,7 +202,20 @@ public abstract class ArchitectureCheck extends DefaultTask {
 		return this.classes.getAsFileTree();
 	}
 
+	@Optional
+	@InputFiles
+	@PathSensitive(PathSensitivity.RELATIVE)
+	public abstract DirectoryProperty getResourcesDirectory();
+
 	@OutputDirectory
 	public abstract DirectoryProperty getOutputDirectory();
 
+	@Internal
+	public abstract ListProperty<ArchRule> getRules();
+
+	@Input
+	// The rules themselves can't be an input as they aren't serializable so we use their
+	// descriptions instead
+	abstract ListProperty<String> getRuleDescriptions();
+
 }

buildSrc/src/main/java/org/springframework/boot/build/architecture/ArchitecturePlugin.java

@@ -50,6 +50,7 @@ public class ArchitecturePlugin implements Plugin<Project> {
 				.register("checkArchitecture" + StringUtils.capitalize(sourceSet.getName()), ArchitectureCheck.class,
 						(task) -> {
 							task.setClasses(sourceSet.getOutput().getClassesDirs());
+							task.getResourcesDirectory().set(sourceSet.getOutput().getResourcesDir());
 							task.setDescription("Checks the architecture of the classes of the " + sourceSet.getName()
 									+ " source set.");
 							task.setGroup(LifecycleBasePlugin.VERIFICATION_GROUP);

buildSrc/src/main/java/org/springframework/boot/build/autoconfigure/AutoConfigurationPlugin.java

@@ -17,29 +17,50 @@
 package org.springframework.boot.build.autoconfigure;
 
 import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.Collections;
+import java.util.List;
 import java.util.concurrent.Callable;
 
+import com.tngtech.archunit.core.domain.JavaClass;
+import com.tngtech.archunit.lang.ArchCondition;
+import com.tngtech.archunit.lang.ArchRule;
+import com.tngtech.archunit.lang.ConditionEvents;
+import com.tngtech.archunit.lang.SimpleConditionEvent;
+import com.tngtech.archunit.lang.syntax.ArchRuleDefinition;
 import org.gradle.api.Plugin;
 import org.gradle.api.Project;
 import org.gradle.api.artifacts.Configuration;
 import org.gradle.api.plugins.JavaPlugin;
 import org.gradle.api.plugins.JavaPluginExtension;
+import org.gradle.api.provider.Provider;
+import org.gradle.api.tasks.PathSensitivity;
 import org.gradle.api.tasks.SourceSet;
 
 import org.springframework.boot.build.DeployedPlugin;
+import org.springframework.boot.build.architecture.ArchitectureCheck;
+import org.springframework.boot.build.architecture.ArchitecturePlugin;
 import org.springframework.boot.build.context.properties.ConfigurationPropertiesPlugin;
 
 /**
  * {@link Plugin} for projects that define auto-configuration. When applied, the plugin
- * applies the {@link DeployedPlugin}. Additionally, it reacts to the presence of the
- * {@link JavaPlugin} by:
+ * applies the {@link DeployedPlugin}. Additionally, when the {@link JavaPlugin} is
+ * applied it:
  *
  * <ul>
- * <li>Applying the {@link ConfigurationPropertiesPlugin}.
- * <li>Adding a dependency on the auto-configuration annotation processor.
- * <li>Defining a task that produces metadata describing the auto-configuration. The
- * metadata is made available as an artifact in the
+ * <li>Applies the {@link ConfigurationPropertiesPlugin}.
+ * <li>Adds a dependency on the auto-configuration annotation processor.
+ * <li>Defines a task that produces metadata describing the auto-configuration. The
+ * metadata is made available as an artifact in the {@code autoConfigurationMetadata}
+ * configuration.
+ * <li>Reacts to the {@link ArchitecturePlugin} being applied and:
+ * <ul>
+ * <li>Adds a rule to the {@code checkArchitectureMain} task to verify that all
+ * {@code AutoConfiguration} classes are listed in the {@code AutoConfiguration.imports}
+ * file.
+ * </ul>
  * </ul>
  *
  * @author Andy Wilkinson
@@ -52,6 +73,8 @@ public class AutoConfigurationPlugin implements Plugin<Project> {
 	 */
 	public static final String AUTO_CONFIGURATION_METADATA_CONFIGURATION_NAME = "autoConfigurationMetadata";
 
+	private static final String AUTO_CONFIGURATION_IMPORTS_PATH = "META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports";
+
 	@Override
 	public void apply(Project project) {
 		project.getPlugins().apply(DeployedPlugin.class);
@@ -80,7 +103,71 @@ public class AutoConfigurationPlugin implements Plugin<Project> {
 							project.provider((Callable<File>) task::getOutputFile),
 							(artifact) -> artifact.builtBy(task));
 			});
+			project.getPlugins().withType(ArchitecturePlugin.class, (architecturePlugin) -> {
+				project.getTasks().named("checkArchitectureMain", ArchitectureCheck.class).configure((task) -> {
+					SourceSet main = project.getExtensions()
+						.getByType(JavaPluginExtension.class)
+						.getSourceSets()
+						.getByName(SourceSet.MAIN_SOURCE_SET_NAME);
+					File resourcesDirectory = main.getOutput().getResourcesDir();
+					task.dependsOn(main.getProcessResourcesTaskName());
+					task.getInputs().files(resourcesDirectory).optional().withPathSensitivity(PathSensitivity.RELATIVE);
+					task.getRules()
+						.add(allClassesAnnotatedWithAutoConfigurationShouldBeListedInAutoConfigurationImports(
+								autoConfigurationImports(project, resourcesDirectory)));
+				});
+			});
 		});
 	}
 
+	private ArchRule allClassesAnnotatedWithAutoConfigurationShouldBeListedInAutoConfigurationImports(
+			Provider<AutoConfigurationImports> imports) {
+		return ArchRuleDefinition.classes()
+			.that()
+			.areAnnotatedWith("org.springframework.boot.autoconfigure.AutoConfiguration")
+			.should(beListedInAutoConfigurationImports(imports))
+			.allowEmptyShould(true);
+	}
+
+	private ArchCondition<JavaClass> beListedInAutoConfigurationImports(Provider<AutoConfigurationImports> imports) {
+		return new ArchCondition<JavaClass>("be listed in " + AUTO_CONFIGURATION_IMPORTS_PATH) {
+
+			@Override
+			public void check(JavaClass item, ConditionEvents events) {
+				AutoConfigurationImports autoConfigurationImports = imports.get();
+				if (!autoConfigurationImports.imports.contains(item.getName())) {
+					events.add(SimpleConditionEvent.violated(item,
+							item.getName() + " was not listed in " + autoConfigurationImports.importsFile));
+				}
+			}
+
+		};
+	}
+
+	private Provider<AutoConfigurationImports> autoConfigurationImports(Project project, File resourcesDirectory) {
+		Path importsFile = new File(resourcesDirectory, AUTO_CONFIGURATION_IMPORTS_PATH).toPath();
+		return project.provider(() -> {
+			try {
+				return new AutoConfigurationImports(project.getProjectDir().toPath().relativize(importsFile),
+						Files.readAllLines(importsFile));
+			}
+			catch (IOException ex) {
+				throw new RuntimeException("Failed to read AutoConfiguration.imports", ex);
+			}
+		});
+	}
+
+	private static final class AutoConfigurationImports {
+
+		private final Path importsFile;
+
+		private final List<String> imports;
+
+		private AutoConfigurationImports(Path importsFile, List<String> imports) {
+			this.importsFile = importsFile;
+			this.imports = imports;
+		}
+
+	}
+
 }