Introduce EnableTestScopedConstructorContext annotation for extensions

documentation/src/docs/asciidoc/link-attributes.adoc

@@ -138,6 +138,7 @@ endif::[]
 :BeforeAllCallback:                          {javadoc-root}/org.junit.jupiter.api/org/junit/jupiter/api/extension/BeforeAllCallback.html[BeforeAllCallback]
 :BeforeEachCallback:                         {javadoc-root}/org.junit.jupiter.api/org/junit/jupiter/api/extension/BeforeEachCallback.html[BeforeEachCallback]
 :BeforeTestExecutionCallback:                {javadoc-root}/org.junit.jupiter.api/org/junit/jupiter/api/extension/BeforeTestExecutionCallback.html[BeforeTestExecutionCallback]
+:EnableTestScopedConstructorContext:         {javadoc-root}/org.junit.jupiter.api/org/junit/jupiter/api/extension/EnableTestScopedConstructorContext.html[@EnableTestScopedConstructorContext]
 :ExecutableInvoker:                          {javadoc-root}/org.junit.jupiter.api/org/junit/jupiter/api/extension/ExecutableInvoker.html[ExecutableInvoker]
 :ExecutionCondition:                         {javadoc-root}/org.junit.jupiter.api/org/junit/jupiter/api/extension/ExecutionCondition.html[ExecutionCondition]
 :ExtendWith:                                 {javadoc-root}/org.junit.jupiter.api/org/junit/jupiter/api/extension/ExtendWith.html[@ExtendWith]

documentation/src/docs/asciidoc/release-notes/release-notes-5.12.0-M1.adoc

@@ -42,7 +42,10 @@ JUnit repository on GitHub.
 [[release-notes-5.12.0-M1-junit-jupiter-deprecations-and-breaking-changes]]
 ==== Deprecations and Breaking Changes
 
-* ❓
+* `ParameterResolver` extensions receive a different `ExtensionContext` for constructor
+  parameters of the test instance. Since the `ExtensionContext` is now consistent with
+  parameters of test methods, extensions are unlikely to break, but the behavior may
+  change in certain scenarios.
 
 [[release-notes-5.12.0-M1-junit-jupiter-new-features-and-improvements]]
 ==== New Features and Improvements
@@ -54,6 +57,12 @@ JUnit repository on GitHub.
   `@ConvertWith`), and `ArgumentsAggregator` (declared via `@AggregateWith`)
   implementations can now use constructor injection from registered `ParameterResolver`
   extensions.
+* Implementations of `ParameterResolver` now receive a test-specific `ExtensionContext`
+  for constructor parameters of the test class.
+* `@EnableTestScopedConstructorContext` has been added to enable the use of a test-scoped
+  `ExtensionContext` in `TestInstancePreConstructCallback`, `TestInstancePostProcessor`
+  and `TestInstanceFactory`. The behavior enabled by the annotation is expected to
+  eventually become the default in future versions of JUnit Jupiter.
 
 
 [[release-notes-5.12.0-M1-junit-vintage]]

documentation/src/docs/asciidoc/user-guide/extensions.adoc

@@ -381,6 +381,12 @@ This extension provides a symmetric call to `{TestInstancePreDestroyCallback}` a
 in combination with other extensions to prepare constructor parameters or keeping track of test
 instances and their lifecycle.
 
+[NOTE]
+====
+You may annotate your extension with `{EnableTestScopedConstructorContext}` for revised
+handling of `CloseableResource` and to make test-specific data available to your implementation.
+====
+
 [[extensions-test-instance-factories]]
 === Test Instance Factories
 
@@ -407,6 +413,12 @@ the user's responsibility to ensure that only a single `TestInstanceFactory` is
 registered for any specific test class.
 ====
 
+[NOTE]
+====
+You may annotate your extension with `{EnableTestScopedConstructorContext}` for revised
+handling of `CloseableResource` and to make test-specific data available to your implementation.
+====
+
 [[extensions-test-instance-post-processing]]
 === Test Instance Post-processing
 
@@ -419,6 +431,12 @@ initialization methods on the test instance, etc.
 For a concrete example, consult the source code for the `{MockitoExtension}` and the
 `{SpringExtension}`.
 
+[NOTE]
+====
+You may annotate your extension with `{EnableTestScopedConstructorContext}` for revised
+handling of `CloseableResource` and to make test-specific data available to your implementation.
+====
+
 [[extensions-test-instance-pre-destroy-callback]]
 === Test Instance Pre-destroy Callback
 

junit-jupiter-api/src/main/java/org/junit/jupiter/api/extension/EnableTestScopedConstructorContext.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2015-2024 the original author or authors.
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License v2.0 which
+ * accompanies this distribution and is available at
+ *
+ * https://www.eclipse.org/legal/epl-v20.html
+ */
+
+package org.junit.jupiter.api.extension;
+
+import static org.apiguardian.api.API.Status.MAINTAINED;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.apiguardian.api.API;
+import org.junit.jupiter.api.TestInstance;
+import org.junit.jupiter.api.extension.ExtensionContext.Store;
+import org.junit.jupiter.api.extension.ExtensionContext.Store.CloseableResource;
+
+/**
+ * {@code @EnableTestScopedConstructorContext} allows
+ * {@link Extension Extensions} to use a test-scoped {@link ExtensionContext}
+ * during creation of test instances.
+ *
+ * <p>The annotation should be used on extension classes.
+ * JUnit will call the following extension callbacks of annotated extensions
+ * with a test-scoped {@link ExtensionContext}, unless the test class is
+ * annotated with {@link TestInstance @TestInstance(Lifecycle.PER_CLASS)}.
+ *
+ * <ul>
+ * <li>{@link TestInstancePreConstructCallback}</li>
+ * <li>{@link TestInstancePostProcessor}</li>
+ * <li>{@link TestInstanceFactory}</li>
+ * </ul>
+ *
+ * <p>Implementations of these extension callbacks can observe the following
+ * differences if they are using {@code @EnableTestScopedConstructorContext}.
+ *
+ * <ul>
+ * <li>{@link ExtensionContext#getElement() getElement()} may refer to the test
+ * method and {@link ExtensionContext#getTestClass() getTestClass()} may refer
+ * to a nested test class. Use {@link TestInstanceFactoryContext#getTestClass()}
+ * to get the class under construction.</li>
+ * <li>{@link ExtensionContext#getTestMethod() getTestMethod()} is no-longer
+ * empty, unless the test class is annotated with
+ * {@link TestInstance @TestInstance(Lifecycle.PER_CLASS)}.</li>
+ * <li>If the callback adds a new {@link CloseableResource CloseableResource} to
+ * the {@link Store Store}, the resource is closed just after the instance is
+ * destroyed.</li>
+ * <li>The callbacks can now access data previously stored by
+ * {@link TestTemplateInvocationContext}, unless the test class is annotated
+ * with {@link TestInstance @TestInstance(Lifecycle.PER_CLASS)}.</li>
+ * </ul>
+ *
+ * <p><strong>Note</strong>: The behavior which is enabled by this annotation is
+ * expected to become the default in future versions of JUnit Jupiter. To ensure
+ * future compatibility, extension vendors are therefore advised to annotate
+ * their extensions, even if they don't need the new functionality.
+ *
+ * @since 5.12
+ * @see TestInstancePreConstructCallback
+ * @see TestInstancePostProcessor
+ * @see TestInstanceFactory
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Inherited
+@API(status = MAINTAINED, since = "5.12")
+public @interface EnableTestScopedConstructorContext {
+}

junit-jupiter-api/src/main/java/org/junit/jupiter/api/extension/TestInstanceFactory.java

@@ -13,6 +13,7 @@
 import static org.apiguardian.api.API.Status.STABLE;
 
 import org.apiguardian.api.API;
+import org.junit.jupiter.api.extension.ExtensionContext.Store.CloseableResource;
 
 /**
  * {@code TestInstanceFactory} defines the API for {@link Extension
@@ -56,6 +57,11 @@ public interface TestInstanceFactory extends Extension {
 	/**
 	 * Callback for creating a test instance for the supplied context.
 	 *
+	 * <p>You may annotate your extension with
+	 * {@link EnableTestScopedConstructorContext @EnableTestScopedConstructorContext}
+	 * for revised handling of {@link CloseableResource CloseableResource} and
+	 * to make test-specific data available to your implementation.
+	 *
 	 * <p><strong>Note</strong>: the {@code ExtensionContext} supplied to a
 	 * {@code TestInstanceFactory} will always return an empty
 	 * {@link java.util.Optional} value from

junit-jupiter-api/src/main/java/org/junit/jupiter/api/extension/TestInstancePostProcessor.java

@@ -13,6 +13,7 @@
 import static org.apiguardian.api.API.Status.STABLE;
 
 import org.apiguardian.api.API;
+import org.junit.jupiter.api.extension.ExtensionContext.Store.CloseableResource;
 
 /**
  * {@code TestInstancePostProcessor} defines the API for {@link Extension
@@ -45,6 +46,11 @@ public interface TestInstancePostProcessor extends Extension {
 	/**
 	 * Callback for post-processing the supplied test instance.
 	 *
+	 * <p>You may annotate your extension with
+	 * {@link EnableTestScopedConstructorContext @EnableTestScopedConstructorContext}
+	 * for revised handling of {@link CloseableResource CloseableResource} and
+	 * to make test-specific data available to your implementation.
+	 *
 	 * <p><strong>Note</strong>: the {@code ExtensionContext} supplied to a
 	 * {@code TestInstancePostProcessor} will always return an empty
 	 * {@link java.util.Optional} value from {@link ExtensionContext#getTestInstance()

junit-jupiter-api/src/main/java/org/junit/jupiter/api/extension/TestInstancePreConstructCallback.java

@@ -14,6 +14,7 @@
 
 import org.apiguardian.api.API;
 import org.junit.jupiter.api.TestInstance.Lifecycle;
+import org.junit.jupiter.api.extension.ExtensionContext.Store.CloseableResource;
 
 /**
  * {@code TestInstancePreConstructCallback} defines the API for {@link Extension
@@ -49,6 +50,11 @@ public interface TestInstancePreConstructCallback extends Extension {
 	/**
 	 * Callback invoked prior to test instances being constructed.
 	 *
+	 * <p>You may annotate your extension with
+	 * {@link EnableTestScopedConstructorContext @EnableTestScopedConstructorContext}
+	 * for revised handling of {@link CloseableResource CloseableResource} and
+	 * to make test-specific data available to your implementation.
+	 *
 	 * @param factoryContext the context for the test instance about to be instantiated;
 	 * never {@code null}
 	 * @param context the current extension context; never {@code null}

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

@@ -39,6 +39,7 @@
 import org.junit.jupiter.api.TestInstance.Lifecycle;
 import org.junit.jupiter.api.extension.AfterAllCallback;
 import org.junit.jupiter.api.extension.BeforeAllCallback;
+import org.junit.jupiter.api.extension.EnableTestScopedConstructorContext;
 import org.junit.jupiter.api.extension.Extension;
 import org.junit.jupiter.api.extension.ExtensionConfigurationException;
 import org.junit.jupiter.api.extension.ExtensionContext;
@@ -66,6 +67,7 @@
 import org.junit.jupiter.engine.extension.ExtensionRegistry;
 import org.junit.jupiter.engine.extension.MutableExtensionRegistry;
 import org.junit.platform.commons.JUnitException;
+import org.junit.platform.commons.util.AnnotationUtils;
 import org.junit.platform.commons.util.ExceptionUtils;
 import org.junit.platform.commons.util.ReflectionUtils;
 import org.junit.platform.commons.util.StringUtils;
@@ -277,15 +279,18 @@ private TestInstancesProvider testInstancesProvider(JupiterEngineExecutionContex
 		// For Lifecycle.PER_CLASS, ourExtensionContext.getTestInstances() is used to store the instance.
 		// Otherwise, extensionContext.getTestInstances() is always empty and we always create a new instance.
 		return (registry, context) -> ourExtensionContext.getTestInstances().orElseGet(
-			() -> instantiateAndPostProcessTestInstance(parentExecutionContext, registry, context));
+			() -> instantiateAndPostProcessTestInstance(parentExecutionContext, ourExtensionContext, registry,
+				context));
 	}
 
 	private TestInstances instantiateAndPostProcessTestInstance(JupiterEngineExecutionContext parentExecutionContext,
-			ExtensionRegistry registry, JupiterEngineExecutionContext context) {
+			ClassExtensionContext ourExtensionContext, ExtensionRegistry registry,
+			JupiterEngineExecutionContext context) {
 
-		TestInstances instances = instantiateTestClass(parentExecutionContext, registry, context);
+		TestInstances instances = instantiateTestClass(parentExecutionContext, ourExtensionContext, registry, context);
 		context.getThrowableCollector().execute(() -> {
-			invokeTestInstancePostProcessors(instances.getInnermostInstance(), registry, context.getExtensionContext());
+			invokeTestInstancePostProcessors(instances.getInnermostInstance(), registry, context.getExtensionContext(),
+				ourExtensionContext);
 			// In addition, we initialize extension registered programmatically from instance fields here
 			// since the best time to do that is immediately following test class instantiation
 			// and post-processing.
@@ -295,27 +300,35 @@ private TestInstances instantiateAndPostProcessTestInstance(JupiterEngineExecuti
 	}
 
 	protected abstract TestInstances instantiateTestClass(JupiterEngineExecutionContext parentExecutionContext,
-			ExtensionRegistry registry, JupiterEngineExecutionContext context);
+			ExtensionContext ourExtensionContext, ExtensionRegistry registry, JupiterEngineExecutionContext context);
 
 	protected TestInstances instantiateTestClass(Optional<TestInstances> outerInstances, ExtensionRegistry registry,
-			ExtensionContext extensionContext) {
+			ExtensionContext extensionContext, ExtensionContext ourExtensionContext) {
 
 		Optional<Object> outerInstance = outerInstances.map(TestInstances::getInnermostInstance);
 		invokeTestInstancePreConstructCallbacks(new DefaultTestInstanceFactoryContext(this.testClass, outerInstance),
-			registry, extensionContext);
+			registry, extensionContext, ourExtensionContext);
 		Object instance = this.testInstanceFactory != null //
-				? invokeTestInstanceFactory(outerInstance, extensionContext) //
-				: invokeTestClassConstructor(outerInstance, registry, extensionContext);
+				? invokeTestInstanceFactory(outerInstance, extensionContext, ourExtensionContext) //
+				: invokeTestClassConstructor(outerInstance, registry, extensionContext, ourExtensionContext);
 		return outerInstances.map(instances -> DefaultTestInstances.of(instances, instance)).orElse(
 			DefaultTestInstances.of(instance));
 	}
 
-	private Object invokeTestInstanceFactory(Optional<Object> outerInstance, ExtensionContext extensionContext) {
+	private Object invokeTestInstanceFactory(Optional<Object> outerInstance, ExtensionContext extensionContext,
+			ExtensionContext ourExtensionContext) {
 		Object instance;
 
 		try {
-			instance = this.testInstanceFactory.createTestInstance(
-				new DefaultTestInstanceFactoryContext(this.testClass, outerInstance), extensionContext);
+			if (AnnotationUtils.isAnnotated(this.testInstanceFactory.getClass(),
+				EnableTestScopedConstructorContext.class)) {
+				instance = this.testInstanceFactory.createTestInstance(
+					new DefaultTestInstanceFactoryContext(this.testClass, outerInstance), extensionContext);
+			}
+			else {
+				instance = this.testInstanceFactory.createTestInstance(
+					new DefaultTestInstanceFactoryContext(this.testClass, outerInstance), ourExtensionContext);
+			}
 		}
 		catch (Throwable throwable) {
 			UnrecoverableExceptions.rethrowIfUnrecoverable(throwable);
@@ -355,24 +368,36 @@ private Object invokeTestInstanceFactory(Optional<Object> outerInstance, Extensi
 	}
 
 	private Object invokeTestClassConstructor(Optional<Object> outerInstance, ExtensionRegistry registry,
-			ExtensionContext extensionContext) {
+			ExtensionContext extensionContext, ExtensionContext ourExtensionContext) {
 
 		Constructor<?> constructor = ReflectionUtils.getDeclaredConstructor(this.testClass);
 		return executableInvoker.invoke(constructor, outerInstance, extensionContext, registry,
 			InvocationInterceptor::interceptTestClassConstructor);
 	}
 
 	private void invokeTestInstancePreConstructCallbacks(TestInstanceFactoryContext factoryContext,
-			ExtensionRegistry registry, ExtensionContext context) {
-		registry.stream(TestInstancePreConstructCallback.class).forEach(
-			extension -> executeAndMaskThrowable(() -> extension.preConstructTestInstance(factoryContext, context)));
+			ExtensionRegistry registry, ExtensionContext context, ExtensionContext ourContext) {
+		registry.stream(TestInstancePreConstructCallback.class).forEach(extension -> {
+			if (AnnotationUtils.isAnnotated(extension.getClass(), EnableTestScopedConstructorContext.class)) {
+				executeAndMaskThrowable(() -> extension.preConstructTestInstance(factoryContext, context));
+			}
+			else {
+				executeAndMaskThrowable(() -> extension.preConstructTestInstance(factoryContext, ourContext));
+			}
+		});
 	}
 
-	private void invokeTestInstancePostProcessors(Object instance, ExtensionRegistry registry,
-			ExtensionContext context) {
+	private void invokeTestInstancePostProcessors(Object instance, ExtensionRegistry registry, ExtensionContext context,
+			ClassExtensionContext ourContext) {
 
-		registry.stream(TestInstancePostProcessor.class).forEach(
-			extension -> executeAndMaskThrowable(() -> extension.postProcessTestInstance(instance, context)));
+		registry.stream(TestInstancePostProcessor.class).forEach(extension -> {
+			if (AnnotationUtils.isAnnotated(extension.getClass(), EnableTestScopedConstructorContext.class)) {
+				executeAndMaskThrowable(() -> extension.postProcessTestInstance(instance, context));
+			}
+			else {
+				executeAndMaskThrowable(() -> extension.postProcessTestInstance(instance, ourContext));
+			}
+		});
 	}
 
 	private void executeAndMaskThrowable(Executable executable) {

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

@@ -20,6 +20,7 @@
 import java.util.Set;
 
 import org.apiguardian.api.API;
+import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.TestInstances;
 import org.junit.jupiter.engine.config.JupiterConfiguration;
 import org.junit.jupiter.engine.execution.JupiterEngineExecutionContext;
@@ -71,8 +72,8 @@ public ExecutionMode getExecutionMode() {
 
 	@Override
 	protected TestInstances instantiateTestClass(JupiterEngineExecutionContext parentExecutionContext,
-			ExtensionRegistry registry, JupiterEngineExecutionContext context) {
-		return instantiateTestClass(Optional.empty(), registry, context.getExtensionContext());
+			ExtensionContext ourExtensionContext, ExtensionRegistry registry, JupiterEngineExecutionContext context) {
+		return instantiateTestClass(Optional.empty(), registry, context.getExtensionContext(), ourExtensionContext);
 	}
 
 }

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

@@ -21,6 +21,7 @@
 import java.util.Set;
 
 import org.apiguardian.api.API;
+import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.TestInstances;
 import org.junit.jupiter.engine.config.JupiterConfiguration;
 import org.junit.jupiter.engine.execution.JupiterEngineExecutionContext;
@@ -74,13 +75,14 @@ public List<Class<?>> getEnclosingTestClasses() {
 
 	@Override
 	protected TestInstances instantiateTestClass(JupiterEngineExecutionContext parentExecutionContext,
-			ExtensionRegistry registry, JupiterEngineExecutionContext context) {
+			ExtensionContext ourExtensionContext, ExtensionRegistry registry, JupiterEngineExecutionContext context) {
 
 		// Extensions registered for nested classes and below are not to be used for instantiating and initializing outer classes
 		ExtensionRegistry extensionRegistryForOuterInstanceCreation = parentExecutionContext.getExtensionRegistry();
 		TestInstances outerInstances = parentExecutionContext.getTestInstancesProvider().getTestInstances(
 			extensionRegistryForOuterInstanceCreation, context);
-		return instantiateTestClass(Optional.of(outerInstances), registry, context.getExtensionContext());
+		return instantiateTestClass(Optional.of(outerInstances), registry, context.getExtensionContext(),
+			ourExtensionContext);
 	}
 
 }