GH-1106: Fix Use Publisher CF with RT.invoke()

Fixes #1106

`RabbitTemplate.invoke()` did not honor `usePublisherConnection`.

Author: garyrussell

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

@@ -205,6 +205,7 @@ public static void registerDeliveryTag(ConnectionFactory connectionFactory, Chan
 	 */
 	public static Connection createConnection(final ConnectionFactory connectionFactory,
 			final boolean publisherConnectionIfPossible) {
+
 		if (publisherConnectionIfPossible) {
 			ConnectionFactory publisherFactory = connectionFactory.getPublisherConnectionFactory();
 			if (publisherFactory != null) {

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/core/RabbitTemplate.java

@@ -2166,16 +2166,21 @@ public <T> T invoke(OperationsCallback<T> action, @Nullable com.rabbitmq.client.
 		RabbitResourceHolder resourceHolder = null;
 		Connection connection = null; // NOSONAR (close)
 		Channel channel;
+		ConnectionFactory connectionFactory = getConnectionFactory();
 		if (isChannelTransacted()) {
-			resourceHolder = ConnectionFactoryUtils.getTransactionalResourceHolder(getConnectionFactory(), true);
+			resourceHolder = ConnectionFactoryUtils.getTransactionalResourceHolder(connectionFactory, true,
+					this.usePublisherConnection);
 			channel = resourceHolder.getChannel();
 			if (channel == null) {
 				ConnectionFactoryUtils.releaseResources(resourceHolder);
 				throw new IllegalStateException("Resource holder returned a null channel");
 			}
 		}
 		else {
-			connection = getConnectionFactory().createConnection(); // NOSONAR - RabbitUtils
+			if (this.usePublisherConnection && connectionFactory.getPublisherConnectionFactory() != null) {
+				connectionFactory = connectionFactory.getPublisherConnectionFactory();
+			}
+			connection = connectionFactory.createConnection(); // NOSONAR - RabbitUtils
 			if (connection == null) {
 				throw new IllegalStateException("Connection factory returned a null connection");
 			}
@@ -2184,7 +2189,7 @@ public <T> T invoke(OperationsCallback<T> action, @Nullable com.rabbitmq.client.
 				if (channel == null) {
 					throw new IllegalStateException("Connection returned a null channel");
 				}
-				if (!getConnectionFactory().isPublisherConfirms()) {
+				if (!connectionFactory.isPublisherConfirms()) {
 					RabbitUtils.setPhysicalCloseRequired(channel, true);
 				}
 				this.dedicatedChannels.set(channel);

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

@@ -518,6 +518,47 @@ public void testAddAndRemoveAfterReceivePostProcessors() {
 		assertThat(afterReceivePostProcessors).containsExactly(mpp2, mpp3);
 	}
 
+	@Test
+	public void testPublisherConnWithInvoke() {
+		org.springframework.amqp.rabbit.connection.ConnectionFactory cf = mock(
+				org.springframework.amqp.rabbit.connection.ConnectionFactory.class);
+		org.springframework.amqp.rabbit.connection.ConnectionFactory pcf = mock(
+				org.springframework.amqp.rabbit.connection.ConnectionFactory.class);
+		given(cf.getPublisherConnectionFactory()).willReturn(pcf);
+		RabbitTemplate template = new RabbitTemplate(cf);
+		template.setUsePublisherConnection(true);
+		org.springframework.amqp.rabbit.connection.Connection conn = mock(
+				org.springframework.amqp.rabbit.connection.Connection.class);
+		Channel channel = mock(Channel.class);
+		given(pcf.createConnection()).willReturn(conn);
+		given(conn.isOpen()).willReturn(true);
+		given(conn.createChannel(false)).willReturn(channel);
+		template.invoke(t -> null);
+		verify(pcf).createConnection();
+		verify(conn).createChannel(false);
+	}
+
+	@Test
+	public void testPublisherConnWithInvokeInTx() {
+		org.springframework.amqp.rabbit.connection.ConnectionFactory cf = mock(
+				org.springframework.amqp.rabbit.connection.ConnectionFactory.class);
+		org.springframework.amqp.rabbit.connection.ConnectionFactory pcf = mock(
+				org.springframework.amqp.rabbit.connection.ConnectionFactory.class);
+		given(cf.getPublisherConnectionFactory()).willReturn(pcf);
+		RabbitTemplate template = new RabbitTemplate(cf);
+		template.setUsePublisherConnection(true);
+		template.setChannelTransacted(true);
+		org.springframework.amqp.rabbit.connection.Connection conn = mock(
+				org.springframework.amqp.rabbit.connection.Connection.class);
+		Channel channel = mock(Channel.class);
+		given(pcf.createConnection()).willReturn(conn);
+		given(conn.isOpen()).willReturn(true);
+		given(conn.createChannel(true)).willReturn(channel);
+		template.invoke(t -> null);
+		verify(pcf).createConnection();
+		verify(conn).createChannel(true);
+	}
+
 	@SuppressWarnings("serial")
 	private class TestTransactionManager extends AbstractPlatformTransactionManager {