GH-1201: Fix for ChannelAwareBatchMessageListener

Resolves #1201

The previous commit did not work with `ChannelAwareBatchMessageListener`.

Also add a test to get `List<o.s.a.c.Message>` in a `@RabbitListener` (which
exposed this issue).

**cherry-pick to 2.2.x**

Author: garyrussell

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/listener/AbstractMessageListenerContainer.java

@@ -56,6 +56,7 @@
 import org.springframework.amqp.rabbit.connection.RabbitResourceHolder;
 import org.springframework.amqp.rabbit.connection.RabbitUtils;
 import org.springframework.amqp.rabbit.connection.RoutingConnectionFactory;
+import org.springframework.amqp.rabbit.listener.api.ChannelAwareBatchMessageListener;
 import org.springframework.amqp.rabbit.listener.api.ChannelAwareMessageListener;
 import org.springframework.amqp.rabbit.listener.exception.FatalListenerExecutionException;
 import org.springframework.amqp.rabbit.listener.exception.FatalListenerStartupException;
@@ -243,6 +244,8 @@ public abstract class AbstractMessageListenerContainer extends RabbitAccessor
 
 	private volatile boolean lazyLoad;
 
+	private boolean isBatchListener;
+
 	@Override
 	public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
 		this.applicationEventPublisher = applicationEventPublisher;
@@ -424,6 +427,8 @@ public void setExposeListenerChannel(boolean exposeListenerChannel) {
 	 */
 	public void setMessageListener(MessageListener messageListener) {
 		this.messageListener = messageListener;
+		this.isBatchListener = messageListener instanceof BatchMessageListener
+				|| messageListener instanceof ChannelAwareBatchMessageListener;
 	}
 
 	/**
@@ -1923,8 +1928,8 @@ private void checkPossibleAuthenticationFailureFatalFromProperty() {
 
 	@Nullable
 	protected List<Message> debatch(Message message) {
-		if (isDeBatchingEnabled() && getBatchingStrategy().canDebatch(message.getMessageProperties())
-				&& getMessageListener() instanceof BatchMessageListener) {
+		if (this.isBatchListener && isDeBatchingEnabled()
+				&& getBatchingStrategy().canDebatch(message.getMessageProperties())) {
 			final List<Message> messageList = new ArrayList<>();
 			getBatchingStrategy().deBatch(message, fragment -> messageList.add(fragment));
 			return messageList;

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/listener/SimpleMessageListenerContainer.java

@@ -56,8 +56,10 @@
 import org.springframework.amqp.rabbit.support.ListenerContainerAware;
 import org.springframework.amqp.rabbit.support.ListenerExecutionFailedException;
 import org.springframework.amqp.rabbit.support.RabbitExceptionTranslator;
+import org.springframework.amqp.support.ConsumerTagStrategy;
 import org.springframework.jmx.export.annotation.ManagedMetric;
 import org.springframework.jmx.support.MetricType;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.PlatformTransactionManager;
 import org.springframework.transaction.support.TransactionSynchronizationManager;
 import org.springframework.transaction.support.TransactionTemplate;
@@ -819,8 +821,9 @@ this.cancellationLock, getAcknowledgeMode(), isChannelTransacted(), actualPrefet
 		if (this.retryDeclarationInterval != null) {
 			consumer.setRetryDeclarationInterval(this.retryDeclarationInterval);
 		}
-		if (getConsumerTagStrategy() != null) {
-			consumer.setTagStrategy(getConsumerTagStrategy()); // NOSONAR never null here
+		ConsumerTagStrategy consumerTagStrategy = getConsumerTagStrategy();
+		if (consumerTagStrategy != null) {
+			consumer.setTagStrategy(consumerTagStrategy);
 		}
 		consumer.setBackOffExecution(getRecoveryBackOff().start());
 		consumer.setShutdownTimeout(getShutdownTimeout());
@@ -1084,7 +1087,7 @@ protected void handleStartupFailure(BackOffExecution backOffExecution) {
 	}
 
 	@Override
-	protected void publishConsumerFailedEvent(String reason, boolean fatal, Throwable t) {
+	protected void publishConsumerFailedEvent(String reason, boolean fatal, @Nullable Throwable t) {
 		if (!fatal || !isRunning()) {
 			super.publishConsumerFailedEvent(reason, fatal, t);
 		}

spring-rabbit/src/test/java/org/springframework/amqp/rabbit/annotation/EnableRabbitBatchIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019 the original author or authors.
+ * Copyright 2019-2020 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.
@@ -34,6 +34,7 @@
 import org.springframework.amqp.rabbit.junit.RabbitAvailable;
 import org.springframework.amqp.rabbit.junit.RabbitAvailableCondition;
 import org.springframework.amqp.support.AmqpHeaders;
+import org.springframework.amqp.support.converter.SimpleMessageConverter;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -50,7 +51,7 @@
  */
 @SpringJUnitConfig
 @DirtiesContext
-@RabbitAvailable(queues = { "batch.1", "batch.2", "batch.3" })
+@RabbitAvailable(queues = { "batch.1", "batch.2", "batch.3", "batch.4" })
 public class EnableRabbitBatchIntegrationTests {
 
 	@Autowired
@@ -99,6 +100,20 @@ public void simpleListConsumerAndProducerBatching() throws InterruptedException
 		assertThat(this.listener.foosConsumerBatchToo.get(3).getBar()).isEqualTo("qux");
 	}
 
+	@Test
+	public void nativeMessageList() throws InterruptedException {
+		this.template.convertAndSend("batch.4", new Foo("foo"));
+		this.template.convertAndSend("batch.4", new Foo("bar"));
+		assertThat(this.listener.nativeMessagesLatch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(this.listener.nativeMessages).hasSize(2);
+		Foo payload = (Foo) new SimpleMessageConverter().fromMessage(this.listener.nativeMessages.get(0));
+		assertThat(payload.getBar()).isEqualTo("foo");
+		assertThat(this.listener.nativeMessages.get(1).getMessageProperties()
+				.getHeaders()
+				.get(AmqpHeaders.BATCH_SIZE))
+				.isEqualTo(2);
+	}
+
 	@Configuration
 	@EnableRabbit
 	public static class Config {
@@ -116,6 +131,11 @@ public DirectRabbitListenerContainerFactory directListenerContainerFactory() {
 			DirectRabbitListenerContainerFactory factory = new DirectRabbitListenerContainerFactory();
 			factory.setConnectionFactory(connectionFactory());
 			factory.setBatchListener(true);
+			factory.setContainerCustomizer(container -> {
+				if (container.getQueueNames()[0].equals("batch.4")) {
+					container.setDeBatchingEnabled(true);
+				}
+			});
 			return factory;
 		}
 
@@ -166,6 +186,10 @@ public static class Listener {
 
 		CountDownLatch fooConsumerBatchTooLatch = new CountDownLatch(1);
 
+		private List<org.springframework.amqp.core.Message> nativeMessages;
+
+		private final CountDownLatch nativeMessagesLatch = new CountDownLatch(1);
+
 		@RabbitListener(queues = "batch.1")
 		public void listen1(List<Foo> in) {
 			this.foos = in;
@@ -184,6 +208,12 @@ public void listen3(List<Foo> in) {
 			this.fooConsumerBatchTooLatch.countDown();
 		}
 
+		@RabbitListener(queues = "batch.4", containerFactory = "directListenerContainerFactory")
+		public void listen4(List<org.springframework.amqp.core.Message> in) {
+			this.nativeMessages = in;
+			this.nativeMessagesLatch.countDown();
+		}
+
 	}
 
 	@SuppressWarnings("serial")