Introduce SearchStrategy.ANCESTORS as a replacement for .PARENTS

Closes gh-6763

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/EndpointWebMvcChildContextConfiguration.java

@@ -151,7 +151,7 @@ public class EndpointWebMvcChildContextConfiguration {
 
 	@Configuration
 	@ConditionalOnClass({ EnableWebSecurity.class, Filter.class })
-	@ConditionalOnBean(name = "springSecurityFilterChain", search = SearchStrategy.PARENTS)
+	@ConditionalOnBean(name = "springSecurityFilterChain", search = SearchStrategy.ANCESTORS)
 	public static class EndpointWebMvcChildContextSecurityConfiguration {
 
 		@Bean

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/OnBeanCondition.java

@@ -123,10 +123,12 @@ class OnBeanCondition extends SpringBootCondition implements ConfigurationCondit
 		return ConditionOutcome.match(matchMessage);
 	}
 
+	@SuppressWarnings("deprecation")
 	private List<String> getMatchingBeans(ConditionContext context,
 			BeanSearchSpec beans) {
 		ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
-		if (beans.getStrategy() == SearchStrategy.PARENTS) {
+		if (beans.getStrategy() == SearchStrategy.PARENTS
+				|| beans.getStrategy() == SearchStrategy.ANCESTORS) {
 			BeanFactory parent = beanFactory.getParentBeanFactory();
 			Assert.isInstanceOf(ConfigurableListableBeanFactory.class, parent,
 					"Unable to use SearchStrategy.PARENTS");

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/SearchStrategy.java

@@ -30,8 +30,15 @@ public enum SearchStrategy {
 
 	/**
 	 * Search all parents and ancestors, but not the current context.
+	 *
+	 * @deprecated since 1.5 in favor of {@link SearchStrategy#ANCESTORS}
 	 */
-	PARENTS,
+	@Deprecated PARENTS,
+
+	/**
+	 * Search all ancestors, but not the current context.
+	 */
+	ANCESTORS,
 
 	/**
 	 * Search the entire hierarchy.

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/condition/ConditionalOnMissingBeanTests.java

@@ -274,6 +274,23 @@ public class ConditionalOnMissingBeanTests {
 		parent.close();
 	}
 
+	@Test
+	public void grandparentIsConsideredWhenUsingAncestorsStrategy() {
+		this.context.register(ExampleBeanConfiguration.class);
+		this.context.refresh();
+		AnnotationConfigApplicationContext parent = new AnnotationConfigApplicationContext();
+		parent.setParent(this.context);
+		parent.refresh();
+		AnnotationConfigApplicationContext child = new AnnotationConfigApplicationContext();
+		child.setParent(parent);
+		child.register(ExampleBeanConfiguration.class,
+				OnBeanInAncestorsConfiguration.class);
+		child.refresh();
+		assertThat(child.getBeansOfType(ExampleBean.class)).hasSize(1);
+		child.close();
+		parent.close();
+	}
+
 	@Test
 	public void currentContextIsIgnoredWhenUsingParentsStrategy() {
 		this.context.refresh();
@@ -285,9 +302,21 @@ public class ConditionalOnMissingBeanTests {
 		assertThat(child.getBeansOfType(ExampleBean.class)).hasSize(2);
 	}
 
+	@Test
+	public void currentContextIsIgnoredWhenUsingAncestorsStrategy() {
+		this.context.refresh();
+		AnnotationConfigApplicationContext child = new AnnotationConfigApplicationContext();
+		child.register(ExampleBeanConfiguration.class,
+				OnBeanInAncestorsConfiguration.class);
+		child.setParent(this.context);
+		child.refresh();
+		assertThat(child.getBeansOfType(ExampleBean.class)).hasSize(2);
+	}
+
 	@Configuration
 	protected static class OnBeanInParentsConfiguration {
 
+		@SuppressWarnings("deprecation")
 		@Bean
 		@ConditionalOnMissingBean(search = SearchStrategy.PARENTS)
 		public ExampleBean exampleBean2() {
@@ -296,6 +325,17 @@ public class ConditionalOnMissingBeanTests {
 
 	}
 
+	@Configuration
+	protected static class OnBeanInAncestorsConfiguration {
+
+		@Bean
+		@ConditionalOnMissingBean(search = SearchStrategy.ANCESTORS)
+		public ExampleBean exampleBean2() {
+			return new ExampleBean("test");
+		}
+
+	}
+
 	@Configuration
 	@ConditionalOnMissingBean(name = "foo")
 	protected static class OnBeanNameConfiguration {

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/condition/ConditionalOnSingleCandidateTests.java

@@ -102,6 +102,46 @@ public class ConditionalOnSingleCandidateTests {
 		parent.close();
 	}
 
+	@Test
+	public void singleCandidateInAncestorsOneCandidateInCurrent() {
+		load();
+		AnnotationConfigApplicationContext child = new AnnotationConfigApplicationContext();
+		child.register(FooConfiguration.class,
+				OnBeanSingleCandidateInAncestorsConfiguration.class);
+		child.setParent(this.context);
+		child.refresh();
+		assertThat(child.containsBean("baz")).isFalse();
+		child.close();
+	}
+
+	@Test
+	public void singleCandidateInAncestorsOneCandidateInParent() {
+		load(FooConfiguration.class);
+		AnnotationConfigApplicationContext child = new AnnotationConfigApplicationContext();
+		child.register(OnBeanSingleCandidateInAncestorsConfiguration.class);
+		child.setParent(this.context);
+		child.refresh();
+		assertThat(child.containsBean("baz")).isTrue();
+		assertThat(child.getBean("baz")).isEqualTo("foo");
+		child.close();
+	}
+
+	@Test
+	public void singleCandidateInAncestorsOneCandidateInGrandparent() {
+		load(FooConfiguration.class);
+		AnnotationConfigApplicationContext parent = new AnnotationConfigApplicationContext();
+		parent.setParent(this.context);
+		parent.refresh();
+		AnnotationConfigApplicationContext child = new AnnotationConfigApplicationContext();
+		child.register(OnBeanSingleCandidateInAncestorsConfiguration.class);
+		child.setParent(parent);
+		child.refresh();
+		assertThat(child.containsBean("baz")).isTrue();
+		assertThat(child.getBean("baz")).isEqualTo("foo");
+		child.close();
+		parent.close();
+	}
+
 	@Test
 	public void singleCandidateMultipleCandidates() {
 		load(FooConfiguration.class, BarConfiguration.class,
@@ -176,6 +216,7 @@ public class ConditionalOnSingleCandidateTests {
 
 	}
 
+	@SuppressWarnings("deprecation")
 	@Configuration
 	@ConditionalOnSingleCandidate(value = String.class, search = SearchStrategy.PARENTS)
 	protected static class OnBeanSingleCandidateInParentsConfiguration {
@@ -187,6 +228,17 @@ public class ConditionalOnSingleCandidateTests {
 
 	}
 
+	@Configuration
+	@ConditionalOnSingleCandidate(value = String.class, search = SearchStrategy.ANCESTORS)
+	protected static class OnBeanSingleCandidateInAncestorsConfiguration {
+
+		@Bean
+		public String baz(String s) {
+			return s;
+		}
+
+	}
+
 	@Configuration
 	@ConditionalOnSingleCandidate(value = String.class, type = "java.lang.String")
 	protected static class OnBeanSingleCandidateTwoTypesConfiguration {