spring-projectsGH-1309: Don't Bind Resource When Sync Not Active

Resolves spring-projects#1309

If the `RabbitTemplate` was called from a `@TransactionalEventListener`,
with phase `AFTER_COMMIT`, a transaction is "active", but synchronizations
are already cleared. It is too late to synchronize this transaction.

We end up with an orphaned `ResourceHolder` with pending transaction commits.

Don't bind the resource holder if synchronization is not active.

However, the proper solution, if users want to synchronize the rabbit transaction
with the global transaction, is to use the `BEFORE_COMMIT` phase.

See the discussion on the Github issue for more information.

**cherry-pick to 2.2.x**

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/connection/ConnectionFactoryUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -147,7 +147,8 @@ private static RabbitResourceHolder doGetTransactionalResourceHolder(// NOSONAR
 			}
 			resourceHolderToUse.addChannel(channel, connection);
 
-			if (!resourceHolderToUse.equals(resourceHolder)) {
+			if (!resourceHolderToUse.equals(resourceHolder)
+					&& TransactionSynchronizationManager.isSynchronizationActive()) {
 				bindResourceToTransaction(resourceHolderToUse, connectionFactory,
 						resourceFactory.isSynchedLocalTransactionAllowed());
 			}
@@ -171,6 +172,7 @@ public static void releaseResources(@Nullable RabbitResourceHolder resourceHolde
 
 	public static RabbitResourceHolder bindResourceToTransaction(RabbitResourceHolder resourceHolder,
 			ConnectionFactory connectionFactory, boolean synched) {
+
 		if (TransactionSynchronizationManager.hasResource(connectionFactory)
 				|| !TransactionSynchronizationManager.isActualTransactionActive() || !synched) {
 			return (RabbitResourceHolder) TransactionSynchronizationManager.getResource(connectionFactory); // NOSONAR never null

spring-rabbit/src/test/java/org/springframework/amqp/rabbit/core/TransactionalEventListenerTests.java

@@ -0,0 +1,141 @@
+/*
+ * Copyright 2021 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.amqp.rabbit.core;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+import java.io.IOException;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.amqp.rabbit.connection.Connection;
+import org.springframework.amqp.rabbit.connection.ConnectionFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+import org.springframework.transaction.PlatformTransactionManager;
+import org.springframework.transaction.TransactionDefinition;
+import org.springframework.transaction.TransactionException;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
+import org.springframework.transaction.annotation.Transactional;
+import org.springframework.transaction.event.TransactionPhase;
+import org.springframework.transaction.event.TransactionalEventListener;
+import org.springframework.transaction.support.AbstractPlatformTransactionManager;
+import org.springframework.transaction.support.DefaultTransactionStatus;
+
+import com.rabbitmq.client.Channel;
+
+/**
+ * @author Gary Russell
+ * @since 2.3.6
+ *
+ */
+@SpringJUnitConfig
+@DirtiesContext
+public class TransactionalEventListenerTests {
+
+	@Test
+	void txCommits(@Autowired Config config, @Autowired AtomicBoolean committed,
+			@Autowired Channel channel) throws IOException {
+
+		config.publish();
+		assertThat(committed.get()).isTrue();
+		verify(channel).txCommit();
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	@EnableTransactionManagement
+	public static class Config {
+
+		@Autowired
+		ApplicationEventPublisher publisher;
+
+		@Autowired
+		RabbitTemplate template;
+
+		@Bean
+		AtomicBoolean committed() {
+			return new AtomicBoolean();
+		}
+
+		@TransactionalEventListener(phase = TransactionPhase.AFTER_COMMIT)
+		public void el(String in) {
+			this.template.convertAndSend("test");
+		}
+
+		@Bean
+		RabbitTemplate template(ConnectionFactory cf) {
+			RabbitTemplate template = new RabbitTemplate(cf);
+			template.setChannelTransacted(true);
+			return template;
+		}
+
+		@Bean
+		Channel channel() {
+			return mock(Channel.class);
+		}
+
+		@Bean
+		ConnectionFactory cf(Channel channel) {
+			ConnectionFactory cf = mock(ConnectionFactory.class);
+			Connection conn = mock(Connection.class);
+			given(conn.isOpen()).willReturn(true);
+			given(cf.createConnection()).willReturn(conn);
+			given(conn.createChannel(true)).willReturn(channel);
+			given(channel.isOpen()).willReturn(true);
+			return cf;
+		}
+
+		@Transactional
+		public void publish() {
+			publisher.publishEvent("test");
+		}
+
+		@Bean
+		PlatformTransactionManager transactionManager(AtomicBoolean committed) {
+			return new AbstractPlatformTransactionManager() {
+
+				@Override
+				protected void doRollback(DefaultTransactionStatus status) throws TransactionException {
+				}
+
+				@Override
+				protected Object doGetTransaction() throws TransactionException {
+					return new Object();
+				}
+
+				@Override
+				protected void doCommit(DefaultTransactionStatus status) throws TransactionException {
+					committed.set(true);
+				}
+
+				@Override
+				protected void doBegin(Object transaction, TransactionDefinition definition) throws TransactionException {
+				}
+			};
+		}
+
+	}
+
+}