Restrict nested configuration class introspection to component types

Issue: SPR-16839

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java

@@ -76,6 +76,7 @@ import org.springframework.core.type.classreading.MetadataReader;
 import org.springframework.core.type.classreading.MetadataReaderFactory;
 import org.springframework.core.type.filter.AssignableTypeFilter;
 import org.springframework.lang.Nullable;
+import org.springframework.stereotype.Component;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.CollectionUtils;
@@ -261,8 +262,10 @@ class ConfigurationClassParser {
 	protected final SourceClass doProcessConfigurationClass(ConfigurationClass configClass, SourceClass sourceClass)
 			throws IOException {
 
-		// Recursively process any member (nested) classes first
-		processMemberClasses(configClass, sourceClass);
+		if (sourceClass.getMetadata().isAnnotated(Component.class.getName())) {
+			// Recursively process any member (nested) classes first
+			processMemberClasses(configClass, sourceClass);
+		}
 
 		// Process any @PropertySource annotations
 		for (AnnotationAttributes propertySource : AnnotationConfigUtils.attributesForRepeatable(

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassUtils.java

@@ -119,7 +119,7 @@ abstract class ConfigurationClassUtils {
 			beanDef.setAttribute(CONFIGURATION_CLASS_ATTRIBUTE, CONFIGURATION_CLASS_LITE);
 		}
 		else {
-			return hasNestedConfigurationClass(metadata, metadataReaderFactory);
+			return false;
 		}
 
 		// It's a full or lite configuration candidate... Let's determine the order value, if any.
@@ -131,40 +131,6 @@ abstract class ConfigurationClassUtils {
 		return true;
 	}
 
-	/**
-	 * Check whether the specified class declares a nested configuration class.
-	 */
-	private static boolean hasNestedConfigurationClass(
-			AnnotationMetadata metadata, MetadataReaderFactory metadataReaderFactory) {
-
-		// Potentially nested configuration classes...
-		if (metadata instanceof StandardAnnotationMetadata) {
-			Class<?> beanClass = ((StandardAnnotationMetadata) metadata).getIntrospectedClass();
-			for (Class<?> memberClass : beanClass.getDeclaredClasses()) {
-				if (isConfigurationCandidate(new StandardAnnotationMetadata(memberClass))) {
-					return true;
-				}
-			}
-		}
-		else {
-			for (String memberName : metadata.getMemberClassNames()) {
-				try {
-					MetadataReader metadataReader = metadataReaderFactory.getMetadataReader(memberName);
-					if (isConfigurationCandidate(metadataReader.getAnnotationMetadata())) {
-						return true;
-					}
-				}
-				catch (IOException ex) {
-					if (logger.isDebugEnabled()) {
-						logger.debug("Could not find class file for introspecting configuration annotations: " +
-								memberName, ex);
-					}
-				}
-			}
-		}
-		return false;
-	}
-
 	/**
 	 * Check the given metadata for a configuration class candidate
 	 * (or nested component class declared within a configuration/component class).

spring-context/src/test/java/org/springframework/context/annotation/ImportVersusDirectRegistrationTests.java

@@ -18,6 +18,7 @@ package org.springframework.context.annotation;
 
 import org.junit.Test;
 
+import org.springframework.beans.factory.NoSuchBeanDefinitionException;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 
 /**
@@ -25,8 +26,8 @@ import org.springframework.beans.factory.support.RootBeanDefinition;
  */
 public class ImportVersusDirectRegistrationTests {
 
-	@Test
-	public void thingIsAvailableWhenOuterConfigurationIsRegisteredDirectly() {
+	@Test(expected = NoSuchBeanDefinitionException.class)
+	public void thingIsNotAvailableWhenOuterConfigurationIsRegisteredDirectly() {
 		try (AnnotationConfigApplicationContext directRegistration = new AnnotationConfigApplicationContext()) {
 			directRegistration.register(AccidentalLiteConfiguration.class);
 			directRegistration.refresh();
@@ -34,8 +35,8 @@ public class ImportVersusDirectRegistrationTests {
 		}
 	}
 
-	@Test
-	public void thingIsAvailableWhenOuterConfigurationIsRegisteredWithClassName() {
+	@Test(expected = NoSuchBeanDefinitionException.class)
+	public void thingIsNotAvailableWhenOuterConfigurationIsRegisteredWithClassName() {
 		try (AnnotationConfigApplicationContext directRegistration = new AnnotationConfigApplicationContext()) {
 			directRegistration.registerBeanDefinition("config",
 					new RootBeanDefinition(AccidentalLiteConfiguration.class.getName()));
@@ -44,8 +45,8 @@ public class ImportVersusDirectRegistrationTests {
 		}
 	}
 
-	@Test
-	public void thingIsAvailableWhenOuterConfigurationIsImported() {
+	@Test(expected = NoSuchBeanDefinitionException.class)
+	public void thingIsNotAvailableWhenOuterConfigurationIsImported() {
 		try (AnnotationConfigApplicationContext viaImport = new AnnotationConfigApplicationContext()) {
 			viaImport.register(Importer.class);
 			viaImport.refresh();