Consider ancestors when finding primary beans for ConditionalOnSingleCandidate

Closes gh-6559

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

@@ -99,7 +99,8 @@ class OnBeanCondition extends SpringBootCondition implements ConfigurationCondit
 				return ConditionOutcome.noMatch(
 						"@ConditionalOnSingleCandidate " + spec + " found no beans");
 			}
-			else if (!hasSingleAutowireCandidate(context.getBeanFactory(), matching)) {
+			else if (!hasSingleAutowireCandidate(context.getBeanFactory(), matching,
+					spec.getStrategy() == SearchStrategy.ALL)) {
 				return ConditionOutcome.noMatch("@ConditionalOnSingleCandidate " + spec
 						+ " found no primary candidate amongst the" + " following "
 						+ matching);
@@ -225,16 +226,19 @@ class OnBeanCondition extends SpringBootCondition implements ConfigurationCondit
 	}
 
 	private boolean hasSingleAutowireCandidate(
-			ConfigurableListableBeanFactory beanFactory, List<String> beanNames) {
+			ConfigurableListableBeanFactory beanFactory, List<String> beanNames,
+			boolean considerHierarchy) {
 		return (beanNames.size() == 1
-				|| getPrimaryBeans(beanFactory, beanNames).size() == 1);
+				|| getPrimaryBeans(beanFactory, beanNames, considerHierarchy)
+						.size() == 1);
 	}
 
 	private List<String> getPrimaryBeans(ConfigurableListableBeanFactory beanFactory,
-			List<String> beanNames) {
+			List<String> beanNames, boolean considerHierarchy) {
 		List<String> primaryBeans = new ArrayList<String>();
 		for (String beanName : beanNames) {
-			BeanDefinition beanDefinition = beanFactory.getBeanDefinition(beanName);
+			BeanDefinition beanDefinition = findBeanDefinition(beanFactory, beanName,
+					considerHierarchy);
 			if (beanDefinition != null && beanDefinition.isPrimary()) {
 				primaryBeans.add(beanName);
 			}
@@ -242,6 +246,20 @@ class OnBeanCondition extends SpringBootCondition implements ConfigurationCondit
 		return primaryBeans;
 	}
 
+	private BeanDefinition findBeanDefinition(ConfigurableListableBeanFactory beanFactory,
+			String beanName, boolean considerHierarchy) {
+		if (beanFactory.containsBeanDefinition(beanName)) {
+			return beanFactory.getBeanDefinition(beanName);
+		}
+		if (considerHierarchy && beanFactory
+				.getParentBeanFactory() instanceof ConfigurableListableBeanFactory) {
+			return findBeanDefinition(((ConfigurableListableBeanFactory) beanFactory
+					.getParentBeanFactory()), beanName, considerHierarchy);
+		}
+		return null;
+
+	}
+
 	private static class BeanSearchSpec {
 
 		private final Class<?> annotationType;

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2016 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.
@@ -35,6 +35,7 @@ import static org.junit.Assert.assertTrue;
  * Tests for {@link ConditionalOnSingleCandidate}.
  *
  * @author Stephane Nicoll
+ * @author Andy Wilkinson
  */
 public class ConditionalOnSingleCandidateTests {
 
@@ -103,6 +104,22 @@ public class ConditionalOnSingleCandidateTests {
 		load(OnBeanSingleCandidateNoTypeConfiguration.class);
 	}
 
+	@Test
+	public void singleCandidateMultipleCandidatesInContextHierarchy() {
+		load(FooPrimaryConfiguration.class, BarConfiguration.class);
+		AnnotationConfigApplicationContext child = new AnnotationConfigApplicationContext();
+		child.setParent(this.context);
+		child.register(OnBeanSingleCandidateConfiguration.class);
+		try {
+			child.refresh();
+			assertTrue(child.containsBean("baz"));
+			assertEquals("foo", child.getBean("baz"));
+		}
+		finally {
+			child.close();
+		}
+	}
+
 	private void load(Class<?>... classes) {
 		this.context.register(classes);
 		this.context.refresh();