Merge pull request #45251 from YongGoose

* pr/45251:
  Polish 'Fail fast when base path and an endpoint mapping are set to '/''
  Fail fast when base path and an endpoint mapping are set to '/'

Closes gh-45251

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2025 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 +23,7 @@ import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.actuate.autoconfigure.endpoint.EndpointAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.endpoint.expose.EndpointExposure;
 import org.springframework.boot.actuate.autoconfigure.endpoint.expose.IncludeExcludeEndpointFilter;
+import org.springframework.boot.actuate.autoconfigure.web.server.ManagementPortType;
 import org.springframework.boot.actuate.endpoint.EndpointAccessResolver;
 import org.springframework.boot.actuate.endpoint.EndpointFilter;
 import org.springframework.boot.actuate.endpoint.EndpointsSupplier;
@@ -33,10 +34,12 @@ import org.springframework.boot.actuate.endpoint.invoke.ParameterValueMapper;
 import org.springframework.boot.actuate.endpoint.web.AdditionalPathsMapper;
 import org.springframework.boot.actuate.endpoint.web.EndpointMediaTypes;
 import org.springframework.boot.actuate.endpoint.web.ExposableWebEndpoint;
+import org.springframework.boot.actuate.endpoint.web.PathMappedEndpoint;
 import org.springframework.boot.actuate.endpoint.web.PathMappedEndpoints;
 import org.springframework.boot.actuate.endpoint.web.PathMapper;
 import org.springframework.boot.actuate.endpoint.web.WebEndpointsSupplier;
 import org.springframework.boot.actuate.endpoint.web.WebOperation;
+import org.springframework.boot.actuate.endpoint.web.WebServerNamespace;
 import org.springframework.boot.actuate.endpoint.web.annotation.WebEndpointDiscoverer;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
@@ -47,6 +50,8 @@ import org.springframework.boot.context.properties.EnableConfigurationProperties
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
 
 /**
  * {@link EnableAutoConfiguration Auto-configuration} for web {@link Endpoint @Endpoint}
@@ -54,6 +59,7 @@ import org.springframework.context.annotation.Configuration;
  *
  * @author Phillip Webb
  * @author Stephane Nicoll
+ * @author Yongjun Hong
  * @since 2.0.0
  */
 @AutoConfiguration(after = EndpointAutoConfiguration.class)
@@ -109,7 +115,32 @@ public class WebEndpointAutoConfiguration {
 	@Bean
 	@ConditionalOnMissingBean
 	public PathMappedEndpoints pathMappedEndpoints(Collection<EndpointsSupplier<?>> endpointSuppliers) {
-		return new PathMappedEndpoints(this.properties.getBasePath(), endpointSuppliers);
+		String basePath = this.properties.getBasePath();
+		PathMappedEndpoints pathMappedEndpoints = new PathMappedEndpoints(basePath, endpointSuppliers);
+		if ((!StringUtils.hasText(basePath) || "/".equals(basePath))
+				&& ManagementPortType.get(this.applicationContext.getEnvironment()) == ManagementPortType.SAME) {
+			assertHasNoRootPaths(pathMappedEndpoints);
+		}
+		return pathMappedEndpoints;
+	}
+
+	private void assertHasNoRootPaths(PathMappedEndpoints endpoints) {
+		for (PathMappedEndpoint endpoint : endpoints) {
+			if (endpoint instanceof ExposableWebEndpoint webEndpoint) {
+				Assert.state(!isMappedToRootPath(webEndpoint),
+						() -> "Management base path and the '" + webEndpoint.getEndpointId()
+								+ "' actuator endpoint 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.");
+			}
+
+		}
+	}
+
+	private boolean isMappedToRootPath(PathMappedEndpoint endpoint) {
+		return endpoint.getRootPath().equals("/")
+				|| endpoint.getAdditionalPaths(WebServerNamespace.SERVER).contains("/");
 	}
 
 	@Bean

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2025 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.

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/web/server/ManagementContextAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2025 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.
@@ -17,7 +17,6 @@
 package org.springframework.boot.actuate.autoconfigure.web.server;
 
 import org.springframework.beans.factory.SmartInitializingSingleton;
-import org.springframework.boot.actuate.autoconfigure.endpoint.web.WebEndpointProperties;
 import org.springframework.boot.actuate.autoconfigure.web.ManagementContextFactory;
 import org.springframework.boot.actuate.autoconfigure.web.ManagementContextType;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
@@ -45,7 +44,7 @@ import org.springframework.util.Assert;
  */
 @AutoConfiguration
 @AutoConfigureOrder(Ordered.LOWEST_PRECEDENCE)
-@EnableConfigurationProperties({ WebEndpointProperties.class, ManagementServerProperties.class })
+@EnableConfigurationProperties(ManagementServerProperties.class)
 public class ManagementContextAutoConfiguration {
 
 	@Configuration(proxyBeanMethods = false)

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/web/annotation/DiscoveredWebEndpoint.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2025 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.
@@ -61,7 +61,8 @@ class DiscoveredWebEndpoint extends AbstractDiscoveredEndpoint<WebOperation> imp
 	}
 
 	private Stream<String> getAdditionalPaths(WebServerNamespace webServerNamespace, AdditionalPathsMapper mapper) {
-		return mapper.getAdditionalPaths(getEndpointId(), webServerNamespace).stream();
+		List<String> additionalPaths = mapper.getAdditionalPaths(getEndpointId(), webServerNamespace);
+		return (additionalPaths != null) ? additionalPaths.stream() : Stream.empty();
 	}
 
 }

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

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2012-2025 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.beans.factory.BeanCreationException;
+import org.springframework.boot.SpringApplication;
+
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+
+/**
+ * Verifies that an exception is thrown when management and server endpoint paths
+ * conflict.
+ *
+ * @author Yongjun Hong
+ */
+class ManagementEndpointConflictSmokeTests {
+
+	@Test
+	void shouldThrowExceptionWhenManagementAndServerPathsConflict() {
+		assertThatExceptionOfType(BeanCreationException.class)
+			.isThrownBy(() -> SpringApplication.run(SampleActuatorApplication.class,
+					"--management.endpoints.web.base-path=/", "--management.endpoints.web.path-mapping.health=/"))
+			.withMessageContaining("Management base path and the 'health' actuator endpoint are both mapped to '/'");
+	}
+
+}