Only add httpServiceProxyRegistry bean when necessary

Update `AbstractHttpServiceRegistrar` so that the
`httpServiceProxyRegistry` bean  is only added when registrations
are found.

Author: philwebb

spring-web/src/main/java/org/springframework/web/service/registry/AbstractHttpServiceRegistrar.java

@@ -147,20 +147,22 @@ public final void registerBeanDefinitions(AnnotationMetadata metadata, BeanDefin
 
 		registerHttpServices(new DefaultGroupRegistry(), metadata);
 
-		RootBeanDefinition proxyRegistryBeanDef = createOrGetRegistry(beanRegistry);
-
-		mergeGroups(proxyRegistryBeanDef);
-
-		this.groupsMetadata.forEachRegistration((groupName, types) -> types.forEach(type -> {
-			RootBeanDefinition proxyBeanDef = new RootBeanDefinition();
-			proxyBeanDef.setBeanClassName(type);
-			proxyBeanDef.setAttribute(HTTP_SERVICE_GROUP_NAME_ATTRIBUTE, groupName);
-			proxyBeanDef.setInstanceSupplier(() -> getProxyInstance(groupName, type));
-			String beanName = (groupName + "#" + type);
-			if (!beanRegistry.containsBeanDefinition(beanName)) {
-				beanRegistry.registerBeanDefinition(beanName, proxyBeanDef);
-			}
-		}));
+		if (this.groupsMetadata.hasRegistrations()) {
+			RootBeanDefinition proxyRegistryBeanDef = createOrGetRegistry(beanRegistry);
+
+			mergeGroups(proxyRegistryBeanDef);
+
+			this.groupsMetadata.forEachRegistration((groupName, types) -> types.forEach(type -> {
+				RootBeanDefinition proxyBeanDef = new RootBeanDefinition();
+				proxyBeanDef.setBeanClassName(type);
+				proxyBeanDef.setAttribute(HTTP_SERVICE_GROUP_NAME_ATTRIBUTE, groupName);
+				proxyBeanDef.setInstanceSupplier(() -> getProxyInstance(groupName, type));
+				String beanName = (groupName + "#" + type);
+				if (!beanRegistry.containsBeanDefinition(beanName)) {
+					beanRegistry.registerBeanDefinition(beanName, proxyBeanDef);
+				}
+			}));
+		}
 	}
 
 	/**

spring-web/src/main/java/org/springframework/web/service/registry/GroupsMetadata.java

@@ -97,6 +97,13 @@ Stream<Registration> registrations() {
 		return this.groupMap.values().stream();
 	}
 
+	/**
+	 * Return if there are any {@link Registration registrations}.
+	 */
+	boolean hasRegistrations() {
+		return !this.groupMap.isEmpty();
+	}
+
 
 	/**
 	 * Registration metadata for an {@link HttpServiceGroup}.

spring-web/src/test/java/org/springframework/web/service/registry/ClientHttpServiceRegistrarTests.java

@@ -22,6 +22,9 @@
 
 import org.junit.jupiter.api.Test;
 
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
 import org.springframework.core.env.StandardEnvironment;
 import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
 import org.springframework.core.type.AnnotationMetadata;
@@ -63,6 +66,13 @@ protected void registerHttpServices(GroupRegistry registry, AnnotationMetadata i
 				TestGroup.ofListing("echo", EchoClientA.class, EchoClientB.class));
 	}
 
+	@Test
+	void registerWhenNoClientsDoesNotCreateBeans() {
+		try (AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(NothingFoundConfiguration.class)) {
+			assertThat(context.getBeanNamesForType(HttpServiceProxyRegistry.class)).isEmpty();
+		}
+	}
+
 	private void assertGroups(TestGroup... expectedGroups) {
 		Map<String, TestGroup> groupMap = this.groupRegistry.groupMap();
 		assertThat(groupMap.size()).isEqualTo(expectedGroups.length);
@@ -75,4 +85,19 @@ private void assertGroups(TestGroup... expectedGroups) {
 		}
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	@Import(NothingFoundRegistrar.class)
+	static class NothingFoundConfiguration {
+
+	}
+
+	static class NothingFoundRegistrar extends AbstractClientHttpServiceRegistrar {
+
+		@Override
+		protected void registerHttpServices(GroupRegistry registry,
+				AnnotationMetadata importingClassMetadata) {
+			findAndRegisterHttpServiceClients(registry, List.of("com.example.missing.package"));
+		}
+	}
+
 }

spring-web/src/test/java/org/springframework/web/service/registry/HttpServiceRegistrarTests.java

@@ -120,8 +120,7 @@ void defaultClientType() {
 	@Test
 	void noRegistrations() {
 		doRegister(registry -> {});
-		assertRegistryBeanDef();
-		assertBeanDefinitionCount(1);
+		assertBeanDefinitionCount(0);
 	}