Use ExceptionHandler when Spring MVC uses a different management port

Update `CompositeHandlerExceptionResolver` to search for beans in
all contexts. Note that `BeanFactoryUtils.beansOfTypeIncludingAncestors`
cannot not be used since we need to pick up all beans, even if they
have the same name.

See gh-31495

Author: terminux

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/web/servlet/CompositeHandlerExceptionResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -23,6 +23,8 @@
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.HierarchicalBeanFactory;
 import org.springframework.beans.factory.ListableBeanFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.web.servlet.error.DefaultErrorAttributes;
@@ -38,6 +40,7 @@
  * @author Stephane Nicoll
  * @author Phillip Webb
  * @author Scott Frederick
+ * @author Guirong Hu
  */
 class CompositeHandlerExceptionResolver implements HandlerExceptionResolver {
 
@@ -57,8 +60,16 @@ public ModelAndView resolveException(HttpServletRequest request, HttpServletResp
 	}
 
 	private List<HandlerExceptionResolver> extractResolvers() {
-		List<HandlerExceptionResolver> list = new ArrayList<>(
-				this.beanFactory.getBeansOfType(HandlerExceptionResolver.class).values());
+		List<HandlerExceptionResolver> list = new ArrayList<>();
+		BeanFactory beanFactory = this.beanFactory;
+		while (beanFactory != null) {
+			if (beanFactory instanceof ListableBeanFactory) {
+				list.addAll(
+						((ListableBeanFactory) beanFactory).getBeansOfType(HandlerExceptionResolver.class).values());
+			}
+			beanFactory = (beanFactory instanceof HierarchicalBeanFactory)
+					? ((HierarchicalBeanFactory) beanFactory).getParentBeanFactory() : null;
+		}
 		list.remove(this);
 		AnnotationAwareOrderComparator.sort(list);
 		if (list.isEmpty()) {

spring-boot-tests/spring-boot-smoke-tests/spring-boot-smoke-test-actuator/src/main/java/smoketest/actuator/SampleRestControllerEndpointWithException.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2012-2022 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
+ *
+ *      https://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 smoketest.actuator;
+
+import org.springframework.boot.actuate.endpoint.web.annotation.RestControllerEndpoint;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Component;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+/**
+ * The Sample rest controller endpoint with exception.
+ *
+ * @author Guirong Hu
+ */
+@Component
+@RestControllerEndpoint(id = "exception")
+public class SampleRestControllerEndpointWithException {
+
+	@GetMapping("/")
+	public String exception() {
+		throw new CustomException();
+	}
+
+	@RestControllerAdvice
+	static class CustomExceptionHandler {
+
+		@ExceptionHandler(CustomException.class)
+		ResponseEntity<String> handleCustomException(CustomException e) {
+			return new ResponseEntity<>("this is a custom exception body", HttpStatus.I_AM_A_TEAPOT);
+		}
+
+	}
+
+	static class CustomException extends RuntimeException {
+
+	}
+
+}

spring-boot-tests/spring-boot-smoke-tests/spring-boot-smoke-test-actuator/src/test/java/smoketest/actuator/ManagementDifferentPortAndEndpointWithExceptionHandlerSampleActuatorApplicationTests.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2012-2022 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
+ *
+ *      https://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 smoketest.actuator;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.actuate.autoconfigure.web.server.LocalManagementPort;
+import org.springframework.boot.actuate.endpoint.web.annotation.RestControllerEndpoint;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration tests for separate management and main service ports with Actuator's MVC
+ * {@link RestControllerEndpoint rest controller endpoints} and {@link ExceptionHandler
+ * exception handler}.
+ *
+ * @author Guirong Hu
+ */
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT,
+		properties = { "management.endpoints.web.exposure.include=*", "management.server.port=0" })
+class ManagementDifferentPortAndEndpointWithExceptionHandlerSampleActuatorApplicationTests {
+
+	@LocalManagementPort
+	private int managementPort;
+
+	@Test
+	void testExceptionHandlerRestControllerEndpoint() {
+		ResponseEntity<String> entity = new TestRestTemplate("user", "password")
+				.getForEntity("http://localhost:" + this.managementPort + "/actuator/exception", String.class);
+		assertThat(entity.getStatusCode()).isEqualTo(HttpStatus.I_AM_A_TEAPOT);
+		assertThat(entity.getBody()).isEqualTo("this is a custom exception body");
+	}
+
+}