Polish configuration properties and binder

Fix a few issues and try a few more things to improve performance.

See gh-9000

spring-boot/src/main/java/org/springframework/boot/context/properties/ConfigurationPropertiesBindingPostProcessor.java

@@ -291,18 +291,21 @@ public class ConfigurationPropertiesBindingPostProcessor implements BeanPostProc
 	@Override
 	public Object postProcessBeforeInitialization(Object bean, String beanName)
 			throws BeansException {
-		ConfigurationProperties annotation = AnnotationUtils
-				.findAnnotation(bean.getClass(), ConfigurationProperties.class);
-		Object bound = bean;
+		ConfigurationProperties annotation = getAnnotation(bean, beanName);
 		if (annotation != null) {
-			bound = postProcessBeforeInitialization(bean, beanName, annotation);
+			postProcessBeforeInitialization(bean, beanName, annotation);
 		}
-		annotation = this.beans.findFactoryAnnotation(beanName,
+		return bean;
+	}
+
+	private ConfigurationProperties getAnnotation(Object bean, String beanName) {
+		ConfigurationProperties annotation = this.beans.findFactoryAnnotation(beanName,
 				ConfigurationProperties.class);
-		if (annotation != null) {
-			bound = postProcessBeforeInitialization(bean, beanName, annotation);
+		if (annotation == null) {
+			annotation = AnnotationUtils.findAnnotation(bean.getClass(),
+					ConfigurationProperties.class);
 		}
-		return bound;
+		return annotation;
 	}
 
 	@Override
@@ -311,7 +314,7 @@ public class ConfigurationPropertiesBindingPostProcessor implements BeanPostProc
 		return bean;
 	}
 
-	private Object postProcessBeforeInitialization(Object bean, String beanName,
+	private void postProcessBeforeInitialization(Object bean, String beanName,
 			ConfigurationProperties annotation) {
 		Binder binder = getBinder();
 		Validator validator = determineValidator(bean);
@@ -319,7 +322,6 @@ public class ConfigurationPropertiesBindingPostProcessor implements BeanPostProc
 		Bindable<?> bindable = Bindable.ofInstance(bean);
 		try {
 			binder.bind(annotation.prefix(), bindable, handler);
-			return bean;
 		}
 		catch (Exception ex) {
 			String targetClass = ClassUtils.getShortName(bean.getClass());

spring-boot/src/main/java/org/springframework/boot/context/properties/bind/Binder.java

@@ -235,11 +235,14 @@ public class Binder {
 
 	private <T> Object bindObject(ConfigurationPropertyName name, Bindable<T> target,
 			BindHandler handler, Context context) throws Exception {
+		ConfigurationProperty property = findProperty(name, context);
+		if (property == null && containsNoDescendantOf(context.streamSources(), name)) {
+			return null;
+		}
 		AggregateBinder<?> aggregateBinder = getAggregateBinder(target, context);
 		if (aggregateBinder != null) {
 			return bindAggregate(name, target, handler, context, aggregateBinder);
 		}
-		ConfigurationProperty property = findProperty(name, context);
 		if (property != null) {
 			return bindProperty(name, target, handler, context, property);
 		}

spring-boot/src/main/java/org/springframework/boot/context/properties/source/ConfigurationPropertySources.java

@@ -21,7 +21,6 @@ import java.util.Map;
 import java.util.Optional;
 import java.util.WeakHashMap;
 import java.util.function.Function;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
@@ -74,7 +73,7 @@ public class ConfigurationPropertySources
 	public Iterator<ConfigurationPropertySource> iterator() {
 		return streamPropertySources(this.propertySources)
 				.filter(s -> !(s instanceof ConfigurationPropertySourcesPropertySource))
-				.map(this::adapt).collect(Collectors.toList()).iterator();
+				.map(this::adapt).iterator();
 	}
 
 	private Stream<PropertySource<?>> streamPropertySources(PropertySources sources) {

spring-boot/src/main/java/org/springframework/boot/context/properties/source/DefaultPropertyMapper.java

@@ -52,6 +52,7 @@ class DefaultPropertyMapper implements PropertyMapper {
 			String convertedName = configurationPropertyName.toString();
 			mapping = Collections.singletonList(
 					new PropertyMapping(convertedName, configurationPropertyName));
+			this.configurationPropertySourceCache.put(configurationPropertyName, mapping);
 		}
 		return mapping;
 	}

spring-boot/src/main/java/org/springframework/boot/context/properties/source/FilteredIterableConfigurationPropertiesSource.java

@@ -49,7 +49,7 @@ class FilteredIterableConfigurationPropertiesSource
 
 	@Override
 	public Optional<Boolean> containsDescendantOf(ConfigurationPropertyName name) {
-		return Optional.of(stream().filter(name::isAncestorOf).findFirst().isPresent());
+		return Optional.of(stream().anyMatch(name::isAncestorOf));
 	}
 
 }

spring-boot/src/main/java/org/springframework/boot/context/properties/source/IterableConfigurationPropertySource.java

@@ -63,7 +63,7 @@ public interface IterableConfigurationPropertySource
 
 	@Override
 	default Optional<Boolean> containsDescendantOf(ConfigurationPropertyName name) {
-		return Optional.of(stream().filter(name::isAncestorOf).findFirst().isPresent());
+		return Optional.of(stream().anyMatch(name::isAncestorOf));
 	}
 
 	@Override

spring-boot/src/main/java/org/springframework/boot/context/properties/source/PropertySourceIterableConfigurationPropertySource.java

@@ -90,7 +90,7 @@ class PropertySourceIterableConfigurationPropertySource
 
 	@Override
 	public Optional<Boolean> containsDescendantOf(ConfigurationPropertyName name) {
-		return Optional.of(stream().filter(name::isAncestorOf).findFirst().isPresent());
+		return Optional.of(stream().anyMatch(name::isAncestorOf));
 	}
 
 	private List<ConfigurationPropertyName> getConfigurationPropertyNames() {