HypermediaAutoConfiguration should back off when Spring MVC absent

Fixes gh-19392

Author: mbhave

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/hateoas/HypermediaAutoConfiguration.java

@@ -36,6 +36,7 @@
 import org.springframework.hateoas.config.EnableHypermediaSupport.HypermediaType;
 import org.springframework.plugin.core.Plugin;
 import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
 
 /**
  * {@link EnableAutoConfiguration Auto-configuration} for Spring HATEOAS's
@@ -47,7 +48,7 @@
  * @since 1.1.0
  */
 @Configuration(proxyBeanMethods = false)
-@ConditionalOnClass({ EntityModel.class, RequestMapping.class, Plugin.class })
+@ConditionalOnClass({ EntityModel.class, RequestMapping.class, RequestMappingHandlerAdapter.class, Plugin.class })
 @ConditionalOnWebApplication
 @AutoConfigureAfter({ WebMvcAutoConfiguration.class, JacksonAutoConfiguration.class,
 		HttpMessageConvertersAutoConfiguration.class, RepositoryRestMvcAutoConfiguration.class })

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/hateoas/HypermediaAutoConfigurationTests.java

@@ -25,6 +25,7 @@
 import org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration;
 import org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration;
 import org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration;
+import org.springframework.boot.test.context.FilteredClassLoader;
 import org.springframework.boot.test.context.runner.WebApplicationContextRunner;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.hateoas.MediaTypes;
@@ -54,6 +55,12 @@ class HypermediaAutoConfigurationTests {
 	private WebApplicationContextRunner contextRunner = new WebApplicationContextRunner()
 			.withUserConfiguration(BaseConfig.class);
 
+	@Test
+	void autoConfigurationWhenSpringMvcNotOnClasspathShouldBackOff() {
+		this.contextRunner.withClassLoader(new FilteredClassLoader(RequestMappingHandlerAdapter.class))
+				.run((context) -> assertThat(context.getBeansOfType(HypermediaConfiguration.class)).isEmpty());
+	}
+
 	@Test
 	void linkDiscoverersCreated() {
 		this.contextRunner.run((context) -> {