Add @IntegrationComponentScan auto-configuration

Update Spring Integration auto-configuration so that
`@IntegrationComponentScan` from `AutoConfigurationPackages` is
implicitly applied. Prior to this commit `@MessagingGateway` interfaces
would only get picked up if `@IntegrationComponentScan` was added
alongside with the `@SpringBootApplication`.

Fixes gh-2037
Closes gh-7718

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/integration/IntegrationAutoConfiguration.java

@@ -16,11 +16,15 @@
 
 package org.springframework.boot.autoconfigure.integration;
 
+import java.util.Map;
+
 import javax.management.MBeanServer;
 
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanFactoryAware;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.boot.autoconfigure.AutoConfigurationPackages;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
@@ -31,9 +35,15 @@ import org.springframework.boot.bind.RelaxedPropertyResolver;
 import org.springframework.context.EnvironmentAware;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
 import org.springframework.core.env.Environment;
+import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.core.type.StandardAnnotationMetadata;
+import org.springframework.integration.annotation.IntegrationComponentScan;
 import org.springframework.integration.config.EnableIntegration;
 import org.springframework.integration.config.EnableIntegrationManagement;
+import org.springframework.integration.config.IntegrationComponentScanRegistrar;
+import org.springframework.integration.gateway.GatewayProxyFactoryBean;
 import org.springframework.integration.jmx.config.EnableIntegrationMBeanExport;
 import org.springframework.integration.monitor.IntegrationMBeanExporter;
 import org.springframework.integration.support.management.IntegrationManagementConfigurer;
@@ -107,6 +117,46 @@ public class IntegrationAutoConfiguration {
 		@Configuration
 		@EnableIntegrationManagement(defaultCountsEnabled = "true", defaultStatsEnabled = "true")
 		protected static class EnableIntegrationManagementConfiguration {
+		}
+
+	}
+
+	@ConditionalOnMissingBean(GatewayProxyFactoryBean.class)
+	@Import(AutoIntegrationComponentScanRegistrar.class)
+	protected static class IntegrationComponentScanAutoConfiguration {
+
+	}
+
+	private static class AutoIntegrationComponentScanRegistrar
+			extends IntegrationComponentScanRegistrar {
+
+		@Override
+		public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata,
+				final BeanDefinitionRegistry registry) {
+			StandardAnnotationMetadata metadata = new StandardAnnotationMetadata(
+					IntegrationComponentScanConfiguration.class, true) {
+
+				@Override
+				public Map<String, Object> getAnnotationAttributes(
+						String annotationName) {
+					Map<String, Object> annotationAttributes = super.getAnnotationAttributes(
+							annotationName);
+					if (IntegrationComponentScan.class.getName().equals(annotationName)) {
+						BeanFactory beanFactory = (BeanFactory) registry;
+						if (AutoConfigurationPackages.has(beanFactory)) {
+							annotationAttributes.put("value",
+									AutoConfigurationPackages.get(beanFactory));
+						}
+					}
+					return annotationAttributes;
+				}
+
+			};
+			super.registerBeanDefinitions(metadata, registry);
+		}
+
+		@IntegrationComponentScan
+		private class IntegrationComponentScanConfiguration {
 
 		}
 

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/integration/IntegrationAutoConfigurationTests.java

@@ -30,6 +30,9 @@ import org.springframework.context.annotation.AnnotationConfigApplicationContext
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Primary;
+import org.springframework.integration.annotation.IntegrationComponentScan;
+import org.springframework.integration.annotation.MessagingGateway;
+import org.springframework.integration.gateway.RequestReplyExchanger;
 import org.springframework.integration.support.channel.HeaderChannelRegistry;
 import org.springframework.integration.support.management.IntegrationManagementConfigurer;
 import org.springframework.jmx.export.MBeanExporter;
@@ -61,24 +64,34 @@ public class IntegrationAutoConfigurationTests {
 	@Test
 	public void integrationIsAvailable() {
 		load();
-		assertThat(this.context.getBean(HeaderChannelRegistry.class)).isNotNull();
+		assertThat(this.context.getBean(TestGateway.class)).isNotNull();
+		assertThat(this.context.getBean(IntegrationAutoConfiguration.IntegrationComponentScanAutoConfiguration.class))
+				.isNotNull();
 	}
 
 	@Test
-	public void parentContext() {
+	public void explicitIntegrationComponentScan() {
 		this.context = new AnnotationConfigApplicationContext();
-		this.context.register(JmxAutoConfiguration.class,
+		this.context.register(IntegrationComponentScanConfiguration.class,
+				JmxAutoConfiguration.class,
 				IntegrationAutoConfiguration.class);
 		this.context.refresh();
+		assertThat(this.context.getBean(TestGateway.class)).isNotNull();
+		assertThat(this.context.getBeansOfType(IntegrationAutoConfiguration.IntegrationComponentScanAutoConfiguration.class))
+				.isEmpty();
+	}
+
+	@Test
+	public void parentContext() {
+		load();
 		AnnotationConfigApplicationContext parent = this.context;
 		this.context = new AnnotationConfigApplicationContext();
 		this.context.setParent(parent);
 		this.context.register(JmxAutoConfiguration.class,
 				IntegrationAutoConfiguration.class);
+		TestPropertySourceUtils.addInlinedPropertiesToEnvironment(this.context, "SPRING_JMX_DEFAULT_DOMAIN=org.foo");
 		this.context.refresh();
 		assertThat(this.context.getBean(HeaderChannelRegistry.class)).isNotNull();
-		((ConfigurableApplicationContext) this.context.getParent()).close();
-		this.context.close();
 	}
 
 	@Test
@@ -151,4 +164,15 @@ public class IntegrationAutoConfigurationTests {
 
 	}
 
+	@Configuration
+	@IntegrationComponentScan
+	static class IntegrationComponentScanConfiguration {
+
+	}
+
+	@MessagingGateway
+	public interface TestGateway extends RequestReplyExchanger {
+
+	}
+
 }