Merge branch '3.1.x'

Closes gh-37337

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

@@ -16,14 +16,18 @@
 
 package org.springframework.boot.context.properties;
 
+import java.lang.reflect.Constructor;
 import java.util.ArrayList;
 import java.util.List;
 
 import org.springframework.aot.generate.GenerationContext;
+import org.springframework.beans.BeansException;
 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.config.SmartInstantiationAwareBeanPostProcessor;
+import org.springframework.boot.context.properties.bind.BindConstructorProvider;
 import org.springframework.boot.context.properties.bind.BindMethod;
 import org.springframework.boot.context.properties.bind.Bindable;
 import org.springframework.boot.context.properties.bind.BindableRuntimeHintsRegistrar;
@@ -43,6 +47,7 @@ class ConfigurationPropertiesBeanFactoryInitializationAotProcessor implements Be
 	@Override
 	public ConfigurationPropertiesReflectionHintsContribution processAheadOfTime(
 			ConfigurableListableBeanFactory beanFactory) {
+		beanFactory.addBeanPostProcessor(new BindConstructorAwareBeanPostProcessor(beanFactory));
 		String[] beanNames = beanFactory.getBeanNamesForAnnotation(ConfigurationProperties.class);
 		List<Bindable<?>> bindables = new ArrayList<>();
 		for (String beanName : beanNames) {
@@ -58,6 +63,37 @@ class ConfigurationPropertiesBeanFactoryInitializationAotProcessor implements Be
 		return (!bindables.isEmpty()) ? new ConfigurationPropertiesReflectionHintsContribution(bindables) : null;
 	}
 
+	/**
+	 * {@link SmartInstantiationAwareBeanPostProcessor} implementation to work around
+	 * framework's constructor resolver for immutable configuration properties.
+	 * <p>
+	 * Constructor binding supports multiple constructors as long as one is identified as
+	 * the candidate for binding. Unfortunately, framework is not aware of such feature
+	 * and attempts to resolve the autowired constructor to use.
+	 */
+	static class BindConstructorAwareBeanPostProcessor implements SmartInstantiationAwareBeanPostProcessor {
+
+		private final ConfigurableListableBeanFactory beanFactory;
+
+		BindConstructorAwareBeanPostProcessor(ConfigurableListableBeanFactory beanFactory) {
+			this.beanFactory = beanFactory;
+		}
+
+		@Override
+		public Constructor<?>[] determineCandidateConstructors(Class<?> beanClass, String beanName)
+				throws BeansException {
+			BindMethod bindMethod = BindMethodAttribute.get(this.beanFactory, beanName);
+			if (bindMethod != null && bindMethod == BindMethod.VALUE_OBJECT) {
+				Constructor<?> bindConstructor = BindConstructorProvider.DEFAULT.getBindConstructor(beanClass, false);
+				if (bindConstructor != null) {
+					return new Constructor<?>[] { bindConstructor };
+				}
+			}
+			return null;
+		}
+
+	}
+
 	static final class ConfigurationPropertiesReflectionHintsContribution
 			implements BeanFactoryInitializationAotContribution {
 

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

@@ -100,6 +100,20 @@ class ConfigurationPropertiesBeanRegistrationAotProcessorTests {
 		});
 	}
 
+	@Test
+	@CompileWithForkedClassLoader
+	void aotContributedInitializerBindsValueObjectWithSpecificConstructor() {
+		compile(createContext(ValueObjectSampleBeanWithSpecificConstructorConfiguration.class), (freshContext) -> {
+			TestPropertySourceUtils.addInlinedPropertiesToEnvironment(freshContext, "test.name=Hello",
+					"test.counter=30");
+			freshContext.refresh();
+			ValueObjectWithSpecificConstructorSampleBean bean = freshContext
+				.getBean(ValueObjectWithSpecificConstructorSampleBean.class);
+			assertThat(bean.name).isEqualTo("Hello");
+			assertThat(bean.counter).isEqualTo(30);
+		});
+	}
+
 	@Test
 	@CompileWithForkedClassLoader
 	void aotContributedInitializerBindsJavaBean() {
@@ -193,6 +207,32 @@ class ConfigurationPropertiesBeanRegistrationAotProcessorTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	@EnableConfigurationProperties(ValueObjectWithSpecificConstructorSampleBean.class)
+	static class ValueObjectSampleBeanWithSpecificConstructorConfiguration {
+
+	}
+
+	@ConfigurationProperties("test")
+	public static class ValueObjectWithSpecificConstructorSampleBean {
+
+		@SuppressWarnings("unused")
+		private final String name;
+
+		@SuppressWarnings("unused")
+		private final Integer counter;
+
+		ValueObjectWithSpecificConstructorSampleBean(String name, Integer counter) {
+			this.name = name;
+			this.counter = counter;
+		}
+
+		private ValueObjectWithSpecificConstructorSampleBean(String name) {
+			this(name, 42);
+		}
+
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	@ConfigurationPropertiesScan(basePackageClasses = BScanConfiguration.class)
 	static class ScanTestConfiguration {