Fix class cast during additional path matching with health probes

Previously, when health probes were enabled, the post-processor of
AutoConfiguredHealthEndpointGroups resulted in the bean no longer
implementing AdditionalPathMapper. This then caused a
ClassCastException when working with AdditionalPathMapper beans
in EndpointRequest's additional path mapping support.

This commit updates the type returned by the post-processor to
implement both HealthEndpointGroups and AdditionalPathMapper, as
AutoConfiguredHealthEndpointGroups does. Its implementation of
getAdditionalPaths produces a result that combines both the
additional paths of the original HealthEndpointGroups bean and its
own additional paths for the probes.

Fixes gh-44052

Author: wilkinsona

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/availability/AvailabilityProbesHealthEndpointGroups.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 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.
@@ -16,14 +16,20 @@
 
 package org.springframework.boot.actuate.autoconfigure.availability;
 
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 
+import org.springframework.boot.actuate.endpoint.EndpointId;
+import org.springframework.boot.actuate.endpoint.web.AdditionalPathsMapper;
 import org.springframework.boot.actuate.endpoint.web.WebServerNamespace;
 import org.springframework.boot.actuate.health.AdditionalHealthEndpointPath;
+import org.springframework.boot.actuate.health.HealthEndpoint;
 import org.springframework.boot.actuate.health.HealthEndpointGroup;
 import org.springframework.boot.actuate.health.HealthEndpointGroups;
 import org.springframework.util.Assert;
@@ -35,7 +41,7 @@
  * @author Brian Clozel
  * @author Madhura Bhave
  */
-class AvailabilityProbesHealthEndpointGroups implements HealthEndpointGroups {
+class AvailabilityProbesHealthEndpointGroups implements HealthEndpointGroups, AdditionalPathsMapper {
 
 	private final HealthEndpointGroups groups;
 
@@ -107,4 +113,23 @@ private boolean isProbeGroup(String name) {
 		return name.equals(LIVENESS) || name.equals(READINESS);
 	}
 
+	@Override
+	public List<String> getAdditionalPaths(EndpointId endpointId, WebServerNamespace webServerNamespace) {
+		if (!HealthEndpoint.ID.equals(endpointId)) {
+			return null;
+		}
+		List<String> additionalPaths = new ArrayList<>();
+		if (this.groups instanceof AdditionalPathsMapper additionalPathsMapper) {
+			additionalPaths.addAll(additionalPathsMapper.getAdditionalPaths(endpointId, webServerNamespace));
+		}
+		additionalPaths.addAll(this.probeGroups.values()
+			.stream()
+			.map(HealthEndpointGroup::getAdditionalPath)
+			.filter(Objects::nonNull)
+			.filter((additionalPath) -> additionalPath.hasNamespace(webServerNamespace))
+			.map(AdditionalHealthEndpointPath::getValue)
+			.toList());
+		return additionalPaths;
+	}
+
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/availability/AvailabilityProbesHealthEndpointGroupsPostProcessorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 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.
@@ -17,10 +17,15 @@
 package org.springframework.boot.actuate.autoconfigure.availability;
 
 import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.Set;
 
 import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
 
+import org.springframework.boot.actuate.endpoint.EndpointId;
+import org.springframework.boot.actuate.endpoint.web.AdditionalPathsMapper;
+import org.springframework.boot.actuate.endpoint.web.WebServerNamespace;
 import org.springframework.boot.actuate.health.HealthEndpointGroup;
 import org.springframework.boot.actuate.health.HealthEndpointGroups;
 import org.springframework.mock.env.MockEnvironment;
@@ -103,6 +108,39 @@ void postProcessHealthEndpointGroupsWhenGroupsAlreadyContainedAndAdditionalPathP
 		assertThat(readiness.getAdditionalPath()).hasToString("server:/readyz");
 	}
 
+	@Test
+	void delegatesAdditionalPathMappingToOriginalBean() {
+		HealthEndpointGroups groups = mock(HealthEndpointGroups.class,
+				Mockito.withSettings().extraInterfaces(AdditionalPathsMapper.class));
+		given(((AdditionalPathsMapper) groups).getAdditionalPaths(EndpointId.of("health"), WebServerNamespace.SERVER))
+			.willReturn(List.of("/one", "/two", "/three"));
+		MockEnvironment environment = new MockEnvironment();
+		AvailabilityProbesHealthEndpointGroupsPostProcessor postProcessor = new AvailabilityProbesHealthEndpointGroupsPostProcessor(
+				environment);
+		HealthEndpointGroups postProcessed = postProcessor.postProcessHealthEndpointGroups(groups);
+		assertThat(postProcessed).isInstanceOf(AdditionalPathsMapper.class);
+		AdditionalPathsMapper additionalPathsMapper = (AdditionalPathsMapper) postProcessed;
+		assertThat(additionalPathsMapper.getAdditionalPaths(EndpointId.of("health"), WebServerNamespace.SERVER))
+			.containsExactly("/one", "/two", "/three");
+	}
+
+	@Test
+	void whenAddAdditionalPathsIsTrueThenIncludesOwnAdditionalPathsInGetAdditionalPathsResult() {
+		HealthEndpointGroups groups = mock(HealthEndpointGroups.class,
+				Mockito.withSettings().extraInterfaces(AdditionalPathsMapper.class));
+		given(((AdditionalPathsMapper) groups).getAdditionalPaths(EndpointId.of("health"), WebServerNamespace.SERVER))
+			.willReturn(List.of("/one", "/two", "/three"));
+		MockEnvironment environment = new MockEnvironment();
+		environment.setProperty("management.endpoint.health.probes.add-additional-paths", "true");
+		AvailabilityProbesHealthEndpointGroupsPostProcessor postProcessor = new AvailabilityProbesHealthEndpointGroupsPostProcessor(
+				environment);
+		HealthEndpointGroups postProcessed = postProcessor.postProcessHealthEndpointGroups(groups);
+		assertThat(postProcessed).isInstanceOf(AdditionalPathsMapper.class);
+		AdditionalPathsMapper additionalPathsMapper = (AdditionalPathsMapper) postProcessed;
+		assertThat(additionalPathsMapper.getAdditionalPaths(EndpointId.of("health"), WebServerNamespace.SERVER))
+			.containsExactly("/one", "/two", "/three", "/livez", "/readyz");
+	}
+
 	private HealthEndpointGroups getPostProcessed(String value) {
 		MockEnvironment environment = new MockEnvironment();
 		environment.setProperty("management.endpoint.health.probes.add-additional-paths", value);