Support @TempDir constructor injection for Java record classes

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/extension/TempDirectory.java

@@ -19,6 +19,7 @@
 import static org.junit.platform.commons.support.AnnotationSupport.findAnnotatedFields;
 import static org.junit.platform.commons.support.AnnotationSupport.findAnnotation;
 import static org.junit.platform.commons.support.ReflectionSupport.makeAccessible;
+import static org.junit.platform.commons.util.ReflectionUtils.isRecordObject;
 
 import java.io.File;
 import java.io.IOException;
@@ -135,7 +136,9 @@ private void injectStaticFields(ExtensionContext context, Class<?> testClass) {
 	}
 
 	private void injectInstanceFields(ExtensionContext context, Object instance) {
-		injectFields(context, instance, instance.getClass(), ModifierSupport::isNotStatic);
+		if (!isRecordObject(instance)) {
+			injectFields(context, instance, instance.getClass(), ModifierSupport::isNotStatic);
+		}
 	}
 
 	private void injectFields(ExtensionContext context, Object testInstance, Class<?> testClass,

junit-platform-commons/src/main/java/org/junit/platform/commons/util/ReflectionUtils.java

@@ -365,6 +365,25 @@ public static boolean isInnerClass(Class<?> clazz) {
 		return !isStatic(clazz) && clazz.isMemberClass();
 	}
 
+	/**
+	 * {@return whether the supplied {@code object} is an instance of a record class}
+	 * @since 1.12
+	 */
+	@API(status = INTERNAL, since = "1.12")
+	public static boolean isRecordObject(Object object) {
+		return object != null && isRecordClass(object.getClass());
+	}
+
+	/**
+	 * {@return whether the supplied {@code clazz} is a record class}
+	 * @since 1.12
+	 */
+	@API(status = INTERNAL, since = "1.12")
+	public static boolean isRecordClass(Class<?> clazz) {
+		Class<?> superclass = clazz.getSuperclass();
+		return superclass != null && "java.lang.Record".equals(superclass.getName());
+	}
+
 	/**
 	 * Determine if the return type of the supplied method is primitive {@code void}.
 	 *

jupiter-tests/src/test/java/org/junit/jupiter/engine/extension/TempDirectoryPerDeclarationTests.java

@@ -164,6 +164,12 @@ void resolvesSeparateTempDirsForEachAnnotationDeclaration(TestInstance.Lifecycle
 		assertThat(testATempDirs).doesNotContainEntry("afterEach2", testBTempDirs.get("afterEach2"));
 	}
 
+	@Test
+	void supportsConstructorInjectionOnRecords() {
+		executeTestsForClass(TempDirRecordTestCase.class).testEvents()//
+				.assertStatistics(stats -> stats.started(1).succeeded(1));
+	}
+
 	@Test
 	@DisplayName("does not prevent constructor parameter resolution")
 	void tempDirectoryDoesNotPreventConstructorParameterResolution() {
@@ -1527,4 +1533,12 @@ void test(@SuppressWarnings("unused") @TempDir Path tempDir) {
 
 	}
 
+	@SuppressWarnings("JUnitMalformedDeclaration")
+	record TempDirRecordTestCase(@TempDir Path tempDir) {
+		@Test
+		void shouldExists() {
+			assertTrue(Files.exists(tempDir));
+		}
+	}
+
 }

platform-tests/src/test/java/org/junit/platform/commons/util/ReflectionUtilsTests.java

@@ -285,6 +285,23 @@ void getInterfaceMethodIfPossible() throws Exception {
 			assertThat(interfaceMethod.getDeclaringClass()).isEqualTo(Closeable.class);
 		}
 
+		@Test
+		void isRecordObject() {
+			assertTrue(ReflectionUtils.isRecordObject(new SomeRecord(1)));
+			assertFalse(ReflectionUtils.isRecordObject(new ClassWithOneCustomConstructor("")));
+			assertFalse(ReflectionUtils.isRecordObject(null));
+		}
+
+		@Test
+		void isRecordClass() {
+			assertTrue(ReflectionUtils.isRecordClass(SomeRecord.class));
+			assertFalse(ReflectionUtils.isRecordClass(ClassWithOneCustomConstructor.class));
+			assertFalse(ReflectionUtils.isRecordClass(Object.class));
+		}
+
+		record SomeRecord(int n) {
+		}
+
 		static class ClassWithVoidAndNonVoidMethods {
 
 			void voidMethod() {