Add fail-fast mechanism when both management base path and endpoint mapping are set to '/'

- Issue #43885

Signed-off-by: yongjunhong <[email protected]>

Author: YongGoose

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

@@ -69,6 +69,7 @@
  *
  * @author Andy Wilkinson
  * @author Phillip Webb
+ * @author Yongjun Hong
  * @since 2.0.0
  */
 @ManagementContextConfiguration(proxyBeanMethods = false)
@@ -93,6 +94,19 @@ public WebMvcEndpointHandlerMapping webEndpointServletHandlerMapping(WebEndpoint
 		allEndpoints.addAll(controllerEndpointsSupplier.getEndpoints());
 		String basePath = webEndpointProperties.getBasePath();
 		EndpointMapping endpointMapping = new EndpointMapping(basePath);
+
+		if (basePath.isEmpty() && ManagementPortType.get(environment).equals(ManagementPortType.SAME)) {
+			for (ExposableWebEndpoint endpoint : webEndpoints) {
+				if ("/".equals(endpoint.getRootPath())) {
+					throw new IllegalStateException(
+							"Management endpoints and endpoint path are both mapped to '/' on the server port which will " +
+									"block access to other endpoints. Please use a different path for management endpoints or " +
+									"map them to a dedicated management port."
+					);
+				}
+			}
+		}
+
 		boolean shouldRegisterLinksMapping = shouldRegisterLinksMapping(webEndpointProperties, environment, basePath);
 		return new WebMvcEndpointHandlerMapping(endpointMapping, webEndpoints, endpointMediaTypes,
 				corsProperties.toCorsConfiguration(), new EndpointLinksResolver(allEndpoints, basePath),
@@ -154,7 +168,7 @@ static EndpointObjectMapperWebMvcConfigurer endpointObjectMapperWebMvcConfigurer
 	static class EndpointObjectMapperWebMvcConfigurer implements WebMvcConfigurer {
 
 		private static final List<MediaType> MEDIA_TYPES = Collections
-			.unmodifiableList(Arrays.asList(MediaType.APPLICATION_JSON, new MediaType("application", "*+json")));
+				.unmodifiableList(Arrays.asList(MediaType.APPLICATION_JSON, new MediaType("application", "*+json")));
 
 		private final EndpointObjectMapper endpointObjectMapper;
 
@@ -181,3 +195,4 @@ private void configure(MappingJackson2HttpMessageConverter converter) {
 	}
 
 }
+

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

@@ -0,0 +1,26 @@
+package smoketest.actuator;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.BeanCreationException;
+import org.springframework.boot.SpringApplication;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+/**
+ * Verifies that an exception is thrown when management and server endpoint paths conflict.
+ *
+ * @author Yongjun Hong
+ */
+class ManagementEndpointConflictSmokeTest {
+
+	@Test
+	void shouldThrowExceptionWhenManagementAndServerPathsConflict() {
+		assertThatThrownBy(() -> {
+			SpringApplication.run(SampleActuatorApplication.class,
+					"--management.endpoints.web.base-path=/",
+					"--management.endpoints.web.path-mapping.health=/");
+		}).isInstanceOf(BeanCreationException.class)
+				.hasMessageContaining("Management endpoints and endpoint path are both mapped to '/'");
+	}
+}