BeanPostProcessors are allowed to return a null bean value in the middle of the chain (SPR-6926)

org.springframework.beans/src/main/java/org/springframework/beans/factory/support/AbstractAutowireCapableBeanFactory.java

@@ -392,6 +392,9 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 		Object result = existingBean;
 		for (BeanPostProcessor beanProcessor : getBeanPostProcessors()) {
 			result = beanProcessor.postProcessBeforeInitialization(result, beanName);
+			if (result == null) {
+				return result;
+			}
 		}
 		return result;
 	}
@@ -402,6 +405,9 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 		Object result = existingBean;
 		for (BeanPostProcessor beanProcessor : getBeanPostProcessors()) {
 			result = beanProcessor.postProcessAfterInitialization(result, beanName);
+			if (result == null) {
+				return result;
+			}
 		}
 		return result;
 	}
@@ -682,11 +688,14 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	 */
 	protected Object getEarlyBeanReference(String beanName, RootBeanDefinition mbd, Object bean) {
 		Object exposedObject = bean;
-		if (!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) {
+		if (bean != null && !mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) {
 			for (BeanPostProcessor bp : getBeanPostProcessors()) {
 				if (bp instanceof SmartInstantiationAwareBeanPostProcessor) {
 					SmartInstantiationAwareBeanPostProcessor ibp = (SmartInstantiationAwareBeanPostProcessor) bp;
 					exposedObject = ibp.getEarlyBeanReference(exposedObject, beanName);
+					if (exposedObject == null) {
+						return exposedObject;
+					}
 				}
 			}
 		}

org.springframework.context/src/test/java/org/springframework/context/annotation/AnnotationConfigApplicationContextTests.java

@@ -27,6 +27,7 @@ import static org.junit.matchers.JUnitMatchers.*;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.NoSuchBeanDefinitionException;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.config.BeanPostProcessor;
 import org.springframework.context.annotation6.ComponentForScanning;
 import org.springframework.context.annotation6.ConfigForScanning;
 import org.springframework.context.annotation6.Jsr330NamedForScanning;
@@ -154,6 +155,31 @@ public class AnnotationConfigApplicationContextTests {
 		assertThat(context.getBean(TestBean.class).name, equalTo("foo"));
 	}
 
+	@Test
+	public void nullReturningBeanPostProcessor() {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+		context.register(AutowiredConfig.class);
+		context.getBeanFactory().addBeanPostProcessor(new BeanPostProcessor() {
+			public Object postProcessBeforeInitialization(Object bean, String beanName) {
+				return (bean instanceof TestBean ? null : bean);
+			}
+			public Object postProcessAfterInitialization(Object bean, String beanName) {
+				return bean;
+			}
+		});
+		context.getBeanFactory().addBeanPostProcessor(new BeanPostProcessor() {
+			public Object postProcessBeforeInitialization(Object bean, String beanName) {
+				bean.getClass().getName();
+				return bean;
+			}
+			public Object postProcessAfterInitialization(Object bean, String beanName) {
+				bean.getClass().getName();
+				return bean;
+			}
+		});
+		context.refresh();
+	}
+
 
 	@Configuration
 	static class Config {