Annotate nullability in org.junit.jupiter.engine.descriptor

Author: marcphilipp

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/AbstractExtensionContext.java

@@ -24,6 +24,7 @@
 import java.util.Set;
 import java.util.function.Function;
 
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.extension.ExecutableInvoker;
 import org.junit.jupiter.api.extension.Extension;
 import org.junit.jupiter.api.extension.ExtensionContext;
@@ -54,6 +55,7 @@ abstract class AbstractExtensionContext<T extends TestDescriptor> implements Ext
 
 	private static final Logger LOGGER = LoggerFactory.getLogger(AbstractExtensionContext.class);
 
+	@Nullable
 	private final ExtensionContext parent;
 	private final EngineExecutionListener engineExecutionListener;
 	private final T testDescriptor;
@@ -64,8 +66,8 @@ abstract class AbstractExtensionContext<T extends TestDescriptor> implements Ext
 	private final LauncherStoreFacade launcherStoreFacade;
 	private final NamespacedHierarchicalStore<org.junit.platform.engine.support.store.Namespace> valuesStore;
 
-	AbstractExtensionContext(ExtensionContext parent, EngineExecutionListener engineExecutionListener, T testDescriptor,
-			JupiterConfiguration configuration, ExtensionRegistry extensionRegistry,
+	AbstractExtensionContext(@Nullable ExtensionContext parent, EngineExecutionListener engineExecutionListener,
+			T testDescriptor, JupiterConfiguration configuration, ExtensionRegistry extensionRegistry,
 			LauncherStoreFacade launcherStoreFacade) {
 
 		Preconditions.notNull(testDescriptor, "TestDescriptor must not be null");
@@ -109,7 +111,7 @@ private NamespacedHierarchicalStore.CloseAction<org.junit.platform.engine.suppor
 	}
 
 	private static NamespacedHierarchicalStore<org.junit.platform.engine.support.store.Namespace> createStore(
-			ExtensionContext parent, LauncherStoreFacade launcherStoreFacade,
+			@Nullable ExtensionContext parent, LauncherStoreFacade launcherStoreFacade,
 			NamespacedHierarchicalStore.CloseAction<org.junit.platform.engine.support.store.Namespace> closeAction) {
 		NamespacedHierarchicalStore<org.junit.platform.engine.support.store.Namespace> parentStore;
 		if (parent == null) {
@@ -172,7 +174,8 @@ private void publishFileEntry(String name, ThrowingConsumer<Path> action,
 			Function<Path, FileEntry> fileEntryCreator) {
 		Path dir = createOutputDirectory();
 		Path path = dir.resolve(name);
-		Preconditions.condition(path.getParent().equals(dir), () -> "name must not contain path separators: " + name);
+		Preconditions.condition(path.getParent() != null && path.getParent().equals(dir),
+			() -> "name must not contain path separators: " + name);
 		try {
 			action.accept(path);
 		}

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/ClassBasedTestDescriptor.java

@@ -10,6 +10,7 @@
 
 package org.junit.jupiter.engine.descriptor;
 
+import static java.util.Objects.requireNonNull;
 import static java.util.stream.Collectors.joining;
 import static org.apiguardian.api.API.Status.INTERNAL;
 import static org.junit.jupiter.engine.descriptor.CallbackSupport.invokeAfterCallbacks;
@@ -37,6 +38,7 @@
 import java.util.function.Supplier;
 
 import org.apiguardian.api.API;
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.TestInstance.Lifecycle;
 import org.junit.jupiter.api.extension.AfterAllCallback;
 import org.junit.jupiter.api.extension.BeforeAllCallback;
@@ -92,7 +94,10 @@ public abstract class ClassBasedTestDescriptor extends JupiterTestDescriptor
 
 	protected final ClassInfo classInfo;
 
+	@Nullable
 	private LifecycleMethods lifecycleMethods;
+
+	@Nullable
 	private TestInstanceFactory testInstanceFactory;
 
 	ClassBasedTestDescriptor(UniqueId uniqueId, Class<?> testClass, Supplier<String> displayNameSupplier,
@@ -148,7 +153,7 @@ private void validateDisplayNameAnnotation(DiscoveryIssueReporter reporter) {
 	}
 
 	protected void validateCoreLifecycleMethods(DiscoveryIssueReporter reporter) {
-		Validatable.reportAndClear(this.lifecycleMethods.discoveryIssues, reporter);
+		Validatable.reportAndClear(requireLifecycleMethods().discoveryIssues, reporter);
 	}
 
 	protected void validateClassTemplateInvocationLifecycleMethods(DiscoveryIssueReporter reporter) {
@@ -198,15 +203,17 @@ public final JupiterEngineExecutionContext prepare(JupiterEngineExecutionContext
 			registerExtensionsFromConstructorParameters(registry, getTestClass());
 		}
 
-		this.lifecycleMethods.beforeAll.forEach(method -> registerExtensionsFromExecutableParameters(registry, method));
+		requireLifecycleMethods().beforeAll.forEach(
+			method -> registerExtensionsFromExecutableParameters(registry, method));
 		// Since registerBeforeEachMethodAdapters() and registerAfterEachMethodAdapters() also
 		// invoke registerExtensionsFromExecutableParameters(), we invoke those methods before
 		// invoking registerExtensionsFromExecutableParameters() for @AfterAll methods,
 		// thereby ensuring proper registration order for extensions registered via @ExtendWith
 		// on parameters in lifecycle methods.
 		registerBeforeEachMethodAdapters(registry);
 		registerAfterEachMethodAdapters(registry);
-		this.lifecycleMethods.afterAll.forEach(method -> registerExtensionsFromExecutableParameters(registry, method));
+		requireLifecycleMethods().afterAll.forEach(
+			method -> registerExtensionsFromExecutableParameters(registry, method));
 		registerExtensionsFromInstanceFields(registry, getTestClass());
 
 		ThrowableCollector throwableCollector = createThrowableCollector();
@@ -288,6 +295,7 @@ public void cleanUp(JupiterEngineExecutionContext context) throws Exception {
 		this.testInstanceFactory = null;
 	}
 
+	@Nullable
 	private TestInstanceFactory resolveTestInstanceFactory(ExtensionRegistry registry) {
 		List<TestInstanceFactory> factories = registry.getExtensions(TestInstanceFactory.class);
 
@@ -347,19 +355,19 @@ protected final TestInstances instantiateTestClass(Optional<TestInstances> outer
 		invokeTestInstancePreConstructCallbacks(new DefaultTestInstanceFactoryContext(getTestClass(), outerInstance),
 			registry, extensionContext);
 		Object instance = this.testInstanceFactory != null //
-				? invokeTestInstanceFactory(outerInstance, extensionContext) //
+				? invokeTestInstanceFactory(this.testInstanceFactory, outerInstance, extensionContext) //
 				: invokeTestClassConstructor(outerInstance, registry, extensionContext);
 		return outerInstances.map(instances -> DefaultTestInstances.of(instances, instance)) //
 				.orElse(DefaultTestInstances.of(instance));
 	}
 
-	private Object invokeTestInstanceFactory(Optional<Object> outerInstance,
+	private Object invokeTestInstanceFactory(TestInstanceFactory testInstanceFactory, Optional<Object> outerInstance,
 			ExtensionContextSupplier extensionContext) {
 		Object instance;
 
 		try {
-			ExtensionContext actualExtensionContext = extensionContext.get(this.testInstanceFactory);
-			instance = this.testInstanceFactory.createTestInstance(
+			ExtensionContext actualExtensionContext = extensionContext.get(testInstanceFactory);
+			instance = testInstanceFactory.createTestInstance(
 				new DefaultTestInstanceFactoryContext(getTestClass(), outerInstance), actualExtensionContext);
 		}
 		catch (Throwable throwable) {
@@ -370,7 +378,7 @@ private Object invokeTestInstanceFactory(Optional<Object> outerInstance,
 			}
 
 			String message = "TestInstanceFactory [%s] failed to instantiate test class [%s]".formatted(
-				this.testInstanceFactory.getClass().getName(), getTestClass().getName());
+				testInstanceFactory.getClass().getName(), getTestClass().getName());
 			if (StringUtils.isNotBlank(throwable.getMessage())) {
 				message += ": " + throwable.getMessage();
 			}
@@ -390,7 +398,7 @@ private Object invokeTestInstanceFactory(Optional<Object> outerInstance,
 				instanceClassName += "@" + Integer.toHexString(System.identityHashCode(instanceClass));
 			}
 			String message = "TestInstanceFactory [%s] failed to return an instance of [%s] and instead returned an instance of [%s].".formatted(
-				this.testInstanceFactory.getClass().getName(), testClassName, instanceClassName);
+				testInstanceFactory.getClass().getName(), testClassName, instanceClassName);
 
 			throw new TestInstantiationException(message);
 		}
@@ -438,7 +446,7 @@ private void invokeBeforeAllMethods(JupiterEngineExecutionContext context) {
 		ThrowableCollector throwableCollector = context.getThrowableCollector();
 		Object testInstance = extensionContext.getTestInstance().orElse(null);
 
-		for (Method method : this.lifecycleMethods.beforeAll) {
+		for (Method method : requireLifecycleMethods().beforeAll) {
 			throwableCollector.execute(() -> {
 				try {
 					executableInvoker.invoke(method, testInstance, extensionContext, registry,
@@ -467,7 +475,7 @@ private void invokeAfterAllMethods(JupiterEngineExecutionContext context) {
 		ThrowableCollector throwableCollector = context.getThrowableCollector();
 		Object testInstance = extensionContext.getTestInstance().orElse(null);
 
-		this.lifecycleMethods.afterAll.forEach(method -> throwableCollector.execute(() -> {
+		requireLifecycleMethods().afterAll.forEach(method -> throwableCollector.execute(() -> {
 			try {
 				executableInvoker.invoke(method, testInstance, extensionContext, registry,
 					ReflectiveInterceptorCall.ofVoidMethod(InvocationInterceptor::interceptAfterAllMethod));
@@ -500,13 +508,13 @@ private boolean isPerClassLifecycle(JupiterEngineExecutionContext context) {
 	}
 
 	private void registerBeforeEachMethodAdapters(ExtensionRegistrar registrar) {
-		registerMethodsAsExtensions(this.lifecycleMethods.beforeEach, registrar,
+		registerMethodsAsExtensions(requireLifecycleMethods().beforeEach, registrar,
 			this::synthesizeBeforeEachMethodAdapter);
 	}
 
 	private void registerAfterEachMethodAdapters(ExtensionRegistrar registrar) {
 		// Make a local copy since findAfterEachMethods() returns an immutable list.
-		List<Method> afterEachMethods = new ArrayList<>(this.lifecycleMethods.afterEach);
+		List<Method> afterEachMethods = new ArrayList<>(requireLifecycleMethods().afterEach);
 
 		// Since the bottom-up ordering of afterEachMethods will later be reversed when the
 		// synthesized AfterEachMethodAdapters are executed within TestMethodTestDescriptor,
@@ -546,14 +554,21 @@ private void invokeMethodInExtensionContext(Method method, ExtensionContext cont
 			ReflectiveInterceptorCall.ofVoidMethod(interceptorCall));
 	}
 
+	private LifecycleMethods requireLifecycleMethods() {
+		return requireNonNull(this.lifecycleMethods);
+	}
+
 	protected static class ClassInfo {
 
 		private final List<DiscoveryIssue> discoveryIssues = new ArrayList<>();
 
 		final Class<?> testClass;
 		final Set<TestTag> tags;
 		final Lifecycle lifecycle;
+
+		@Nullable
 		ExecutionMode defaultChildExecutionMode;
+
 		final ExclusiveResourceCollector exclusiveResourceCollector;
 
 		ClassInfo(Class<?> testClass, JupiterConfiguration configuration) {

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/ClassExtensionContext.java

@@ -15,6 +15,7 @@
 import java.util.List;
 import java.util.Optional;
 
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.TestInstance.Lifecycle;
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.TestInstances;
@@ -33,6 +34,7 @@ final class ClassExtensionContext extends AbstractExtensionContext<ClassBasedTes
 
 	private final ThrowableCollector throwableCollector;
 
+	@Nullable
 	private TestInstances testInstances;
 
 	ClassExtensionContext(ExtensionContext parent, EngineExecutionListener engineExecutionListener,

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/ClassTemplateInvocationTestDescriptor.java

@@ -10,6 +10,7 @@
 
 package org.junit.jupiter.engine.descriptor;
 
+import static java.util.Objects.requireNonNull;
 import static org.apiguardian.api.API.Status.INTERNAL;
 import static org.junit.jupiter.engine.descriptor.CallbackSupport.invokeAfterCallbacks;
 import static org.junit.jupiter.engine.descriptor.CallbackSupport.invokeBeforeCallbacks;
@@ -23,6 +24,7 @@
 import java.util.stream.Stream;
 
 import org.apiguardian.api.API;
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.extension.AfterClassTemplateInvocationCallback;
 import org.junit.jupiter.api.extension.BeforeClassTemplateInvocationCallback;
 import org.junit.jupiter.api.extension.ClassTemplateInvocationContext;
@@ -46,11 +48,14 @@ public class ClassTemplateInvocationTestDescriptor extends JupiterTestDescriptor
 	public static final String SEGMENT_TYPE = "class-template-invocation";
 
 	private final ClassTemplateTestDescriptor parent;
+
+	@Nullable
 	private ClassTemplateInvocationContext invocationContext;
+
 	private final int index;
 
 	public ClassTemplateInvocationTestDescriptor(UniqueId uniqueId, ClassTemplateTestDescriptor parent,
-			ClassTemplateInvocationContext invocationContext, int index, TestSource source,
+			ClassTemplateInvocationContext invocationContext, int index, @Nullable TestSource source,
 			JupiterConfiguration configuration) {
 		super(uniqueId, invocationContext.getDisplayName(index), source, configuration);
 		this.parent = parent;
@@ -67,7 +72,7 @@ public int getIndex() {
 	@Override
 	protected ClassTemplateInvocationTestDescriptor withUniqueId(UnaryOperator<UniqueId> uniqueIdTransformer) {
 		return new ClassTemplateInvocationTestDescriptor(uniqueIdTransformer.apply(getUniqueId()), parent,
-			this.invocationContext, this.index, getSource().orElse(null), this.configuration);
+			requiredInvocationContext(), this.index, getSource().orElse(null), this.configuration);
 	}
 
 	// --- TestDescriptor ------------------------------------------------------
@@ -111,18 +116,18 @@ public Function<ResourceLocksProvider, Set<ResourceLocksProvider.Lock>> getResou
 	@Override
 	public JupiterEngineExecutionContext prepare(JupiterEngineExecutionContext context) {
 		MutableExtensionRegistry registry = context.getExtensionRegistry();
-		List<Extension> additionalExtensions = this.invocationContext.getAdditionalExtensions();
+		List<Extension> additionalExtensions = requiredInvocationContext().getAdditionalExtensions();
 		if (!additionalExtensions.isEmpty()) {
 			MutableExtensionRegistry childRegistry = createRegistryFrom(registry, Stream.empty());
 			additionalExtensions.forEach(
-				extension -> childRegistry.registerExtension(extension, this.invocationContext));
+				extension -> childRegistry.registerExtension(extension, requiredInvocationContext()));
 			registry = childRegistry;
 		}
 		ExtensionContext extensionContext = new ClassTemplateInvocationExtensionContext(context.getExtensionContext(),
 			context.getExecutionListener(), this, context.getConfiguration(), registry,
 			context.getLauncherStoreFacade());
 		ThrowableCollector throwableCollector = createThrowableCollector();
-		throwableCollector.execute(() -> this.invocationContext.prepareInvocation(extensionContext));
+		throwableCollector.execute(() -> requiredInvocationContext().prepareInvocation(extensionContext));
 		return context.extend() //
 				.withExtensionRegistry(registry) //
 				.withExtensionContext(extensionContext) //
@@ -177,4 +182,8 @@ public void cleanUp(JupiterEngineExecutionContext context) throws Exception {
 		this.invocationContext = null;
 		super.cleanUp(context);
 	}
+
+	private ClassTemplateInvocationContext requiredInvocationContext() {
+		return requireNonNull(this.invocationContext);
+	}
 }

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/DisplayNameUtils.java

@@ -22,6 +22,7 @@
 import java.util.function.BiFunction;
 import java.util.function.Supplier;
 
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.DisplayNameGeneration;
 import org.junit.jupiter.api.DisplayNameGenerator;
@@ -82,7 +83,7 @@ static String determineDisplayName(AnnotatedElement element, Supplier<String> di
 	}
 
 	static void validateAnnotation(AnnotatedElement element, Supplier<String> elementDescription,
-			Supplier<TestSource> sourceProvider, DiscoveryIssueReporter reporter) {
+			Supplier<@Nullable TestSource> sourceProvider, DiscoveryIssueReporter reporter) {
 		findAnnotation(element, DisplayName.class) //
 				.map(DisplayName::value) //
 				.filter(StringUtils::isBlank) //

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/DynamicNodeTestDescriptor.java

@@ -10,6 +10,7 @@
 
 package org.junit.jupiter.engine.descriptor;
 
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.DynamicNode;
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.engine.config.JupiterConfiguration;
@@ -27,7 +28,7 @@ abstract class DynamicNodeTestDescriptor extends JupiterTestDescriptor {
 
 	protected final int index;
 
-	DynamicNodeTestDescriptor(UniqueId uniqueId, int index, DynamicNode dynamicNode, TestSource testSource,
+	DynamicNodeTestDescriptor(UniqueId uniqueId, int index, DynamicNode dynamicNode, @Nullable TestSource testSource,
 			JupiterConfiguration configuration) {
 		super(uniqueId, dynamicNode.getDisplayName(), testSource, configuration);
 		this.index = index;