Fix feign scanning that fails if clients attr is not use

fixes gh-584

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/feign/FeignClientsRegistrar.java

@@ -109,8 +109,11 @@ public class FeignClientsRegistrar implements ImportBeanDefinitionRegistrar,
 		Map<String, Object> attrs = metadata.getAnnotationAttributes(
 				EnableFeignClients.class.getName());
 		AnnotationTypeFilter annotationTypeFilter = new AnnotationTypeFilter(FeignClient.class);
-		if (attrs != null && attrs.containsKey("clients")) {
-			final Class<?>[] clients = (Class<?>[]) attrs.get("clients");
+		final Class<?>[] clients = attrs == null ? null : (Class<?>[]) attrs.get("clients");
+		if (clients == null || clients.length == 0) {
+			scanner.addIncludeFilter(annotationTypeFilter);
+			basePackages = getBasePackages(metadata);
+		} else {
 			final Set<String> clientClasses = new HashSet<>();
 			basePackages = new HashSet<>();
 			for (Class<?> clazz : clients) {
@@ -125,9 +128,6 @@ public class FeignClientsRegistrar implements ImportBeanDefinitionRegistrar,
 				}
 			};
 			scanner.addIncludeFilter(new AllTypeFilter(Arrays.asList(filter, annotationTypeFilter)));
-		} else {
-			scanner.addIncludeFilter(annotationTypeFilter);
-			basePackages = getBasePackages(metadata);
 		}
 
 		for (String basePackage : basePackages) {

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/feign/valid/FeignClientTests.java

@@ -247,18 +247,18 @@ public class FeignClientTests {
 	public static class Hello {
 		private String message;
 	}
-}
 
-// Load balancer with fixed server list for "local" pointing to localhost
-@Configuration
-class LocalRibbonClientConfiguration {
+	// Load balancer with fixed server list for "local" pointing to localhost
+	@Configuration
+	public static class LocalRibbonClientConfiguration {
 
-	@Value("${local.server.port}")
-	private int port = 0;
+		@Value("${local.server.port}")
+		private int port = 0;
+
+		@Bean
+		public ServerList<Server> ribbonServerList() {
+			return new StaticServerList<>(new Server("localhost", this.port));
+		}
 
-	@Bean
-	public ServerList<Server> ribbonServerList() {
-		return new StaticServerList<>(new Server("localhost", this.port));
 	}
-
 }

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/feign/valid/scanning/FeignClientScanningTests.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright 2013-2015 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
+ *
+ *      http://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.cloud.netflix.feign.valid.scanning;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.builder.SpringApplicationBuilder;
+import org.springframework.boot.test.SpringApplicationConfiguration;
+import org.springframework.boot.test.WebIntegrationTest;
+import org.springframework.cloud.netflix.feign.EnableFeignClients;
+import org.springframework.cloud.netflix.feign.FeignClient;
+import org.springframework.cloud.netflix.ribbon.RibbonClient;
+import org.springframework.cloud.netflix.ribbon.StaticServerList;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.netflix.loadbalancer.Server;
+import com.netflix.loadbalancer.ServerList;
+
+import feign.Client;
+
+/**
+ * @author Spencer Gibb
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@SpringApplicationConfiguration(classes = FeignClientScanningTests.Application.class)
+@WebIntegrationTest(randomPort = true, value = { "spring.application.name=feignclienttest",
+	"feign.httpclient.enabled=false"})
+@DirtiesContext
+public class FeignClientScanningTests {
+
+	@Value("${local.server.port}")
+	private int port = 0;
+
+	@Autowired
+	private TestClient testClient;
+
+	@Autowired
+	private Client feignClient;
+
+	@FeignClient("localapp")
+	protected interface TestClient {
+		@RequestMapping(method = RequestMethod.GET, value = "/hello")
+		String getHello();
+	}
+
+	@Configuration
+	@EnableAutoConfiguration
+	@RestController
+	@EnableFeignClients // NO clients attribute. That's what this class is testing!
+	@RibbonClient(name = "localapp", configuration = LocalRibbonClientConfiguration.class)
+	protected static class Application {
+		@RequestMapping(method = RequestMethod.GET, value = "/hello")
+		public String getHello() {
+			return "hello world 1";
+		}
+
+		public static void main(String[] args) {
+			new SpringApplicationBuilder(Application.class).properties(
+					"spring.application.name=feignclienttest",
+					"management.contextPath=/admin").run(args);
+		}
+	}
+
+	@Test
+	public void testSimpleType() {
+		String hello = this.testClient.getHello();
+		assertNotNull("hello was null", hello);
+		assertEquals("first hello didn't match", "hello world 1", hello);
+	}
+
+	// Load balancer with fixed server list for "local" pointing to localhost
+	@Configuration
+	public static class LocalRibbonClientConfiguration {
+
+		@Value("${local.server.port}")
+		private int port = 0;
+
+		@Bean
+		public ServerList<Server> ribbonServerList() {
+			return new StaticServerList<>(new Server("localhost", this.port));
+		}
+
+	}
+}