Detect invalid transaction configuration for transactional event listeners

Closes gh-30679

spring-tx/src/main/java/org/springframework/transaction/event/TransactionalApplicationListenerMethodAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,6 +25,8 @@ import org.springframework.context.event.ApplicationListenerMethodAdapter;
 import org.springframework.context.event.EventListener;
 import org.springframework.context.event.GenericApplicationListener;
 import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.scheduling.annotation.Async;
+import org.springframework.transaction.annotation.Transactional;
 import org.springframework.transaction.support.TransactionSynchronizationManager;
 import org.springframework.util.Assert;
 
@@ -68,6 +70,11 @@ public class TransactionalApplicationListenerMethodAdapter extends ApplicationLi
 		if (ann == null) {
 			throw new IllegalStateException("No TransactionalEventListener annotation found on method: " + method);
 		}
+		if (AnnotatedElementUtils.hasAnnotation(method, Transactional.class) &&
+				!AnnotatedElementUtils.hasAnnotation(method, Async.class)) {
+			throw new IllegalStateException("@TransactionalEventListener method must not be annotated " +
+					"with @Transactional, unless when declared as @Async: " + method);
+		}
 		this.annotation = ann;
 		this.transactionPhase = ann.phase();
 	}

spring-tx/src/test/java/org/springframework/transaction/event/TransactionalApplicationListenerMethodAdapterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,12 +24,15 @@ import org.springframework.context.PayloadApplicationEvent;
 import org.springframework.context.event.ApplicationListenerMethodAdapter;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.scheduling.annotation.Async;
+import org.springframework.transaction.annotation.Transactional;
 import org.springframework.transaction.support.TransactionSynchronization;
 import org.springframework.transaction.support.TransactionSynchronizationManager;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ReflectionUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 import static org.assertj.core.api.Assertions.assertThatRuntimeException;
 
 /**
@@ -123,6 +126,19 @@ public class TransactionalApplicationListenerMethodAdapterTests {
 		assertThat(adapter.getListenerId()).endsWith("identifier");
 	}
 
+	@Test
+	public void withTransactionalAnnotation() {
+		Method m = ReflectionUtils.findMethod(SampleEvents.class, "withTransactionalAnnotation", String.class);
+		assertThatIllegalStateException().isThrownBy(() -> createTestInstance(m));
+	}
+
+	@Test
+	public void withAsyncTransactionalAnnotation() {
+		Method m = ReflectionUtils.findMethod(SampleEvents.class, "withAsyncTransactionalAnnotation", String.class);
+		supportsEventType(true, m, createGenericEventType(String.class));
+		supportsEventType(false, m, createGenericEventType(Double.class));
+	}
+
 
 	private static void assertPhase(Method method, TransactionPhase expected) {
 		assertThat(method).as("Method must not be null").isNotNull();
@@ -194,6 +210,16 @@ public class TransactionalApplicationListenerMethodAdapterTests {
 		@TransactionalEventListener(id = "identifier")
 		public void identified(String data) {
 		}
+
+		@TransactionalEventListener
+		@Transactional
+		public void withTransactionalAnnotation(String data) {
+		}
+
+		@TransactionalEventListener
+		@Async @Transactional
+		public void withAsyncTransactionalAnnotation(String data) {
+		}
 	}
 
 }