Fix singleton handling of ConfigurationProperties hints

Closes spring-projectsgh-31248

Author: snicoll

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

@@ -39,7 +39,6 @@
 import org.springframework.beans.factory.aot.BeanFactoryInitializationAotContribution;
 import org.springframework.beans.factory.aot.BeanFactoryInitializationAotProcessor;
 import org.springframework.beans.factory.aot.BeanFactoryInitializationCode;
-import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.boot.context.properties.bind.Bindable;
 import org.springframework.core.ResolvableType;
@@ -64,8 +63,10 @@ public BeanFactoryInitializationAotContribution processAheadOfTime(ConfigurableL
 		String[] beanNames = beanFactory.getBeanNamesForAnnotation(ConfigurationProperties.class);
 		List<Class<?>> types = new ArrayList<>();
 		for (String beanName : beanNames) {
-			BeanDefinition beanDefinition = beanFactory.getMergedBeanDefinition(beanName);
-			types.add(ClassUtils.getUserClass(beanDefinition.getResolvableType().toClass()));
+			Class<?> beanType = beanFactory.getType(beanName, false);
+			if (beanType != null) {
+				types.add(ClassUtils.getUserClass(beanType));
+			}
 		}
 		if (!CollectionUtils.isEmpty(types)) {
 			return new ConfigurationPropertiesReflectionHintsContribution(types);

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/ConfigurationPropertiesBeanFactoryInitializationAotProcessorTests.java

@@ -37,6 +37,7 @@
 import org.springframework.beans.factory.aot.BeanFactoryInitializationAotContribution;
 import org.springframework.beans.factory.aot.BeanFactoryInitializationAotProcessor;
 import org.springframework.beans.factory.aot.BeanFactoryInitializationCode;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.context.ApplicationContext;
@@ -61,7 +62,6 @@ void configurationPropertiesBeanFactoryInitializationAotProcessorIsRegistered()
 		assertThat(new AotFactoriesLoader(new DefaultListableBeanFactory())
 				.load(BeanFactoryInitializationAotProcessor.class))
 						.anyMatch(ConfigurationPropertiesBeanFactoryInitializationAotProcessor.class::isInstance);
-
 	}
 
 	@Test
@@ -71,6 +71,15 @@ void processNoMatchesReturnsNullContribution() {
 		assertThat(this.processor.processAheadOfTime(beanFactory)).isNull();
 	}
 
+	@Test
+	void processManuallyRegisteredSingleton() {
+		DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
+		beanFactory.registerSingleton("test", new SampleProperties());
+		RuntimeHints runtimeHints = process(beanFactory);
+		assertThat(runtimeHints.reflection().typeHints()).singleElement()
+				.satisfies(javaBeanBinding(SampleProperties.class));
+	}
+
 	@Test
 	void processJavaBeanConfigurationProperties() {
 		RuntimeHints runtimeHints = process(SampleProperties.class);
@@ -245,6 +254,10 @@ private RuntimeHints process(Class<?>... types) {
 		for (Class<?> type : types) {
 			beanFactory.registerBeanDefinition(type.getName(), new RootBeanDefinition(type));
 		}
+		return process(beanFactory);
+	}
+
+	private RuntimeHints process(ConfigurableListableBeanFactory beanFactory) {
 		BeanFactoryInitializationAotContribution contribution = this.processor.processAheadOfTime(beanFactory);
 		assertThat(contribution).isNotNull();
 		GenerationContext generationContext = new DefaultGenerationContext(new InMemoryGeneratedFiles());