Defensively check for pre-resolved FactoryBean.getObject() results in circular reference scenarios

Issue: SPR-11937

spring-beans/src/main/java/org/springframework/beans/factory/support/FactoryBeanRegistrySupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -90,7 +90,7 @@ public abstract class FactoryBeanRegistrySupport extends DefaultSingletonBeanReg
 	 * Obtain an object to expose from the given FactoryBean.
 	 * @param factory the FactoryBean instance
 	 * @param beanName the name of the bean
-	 * @param shouldPostProcess whether the bean is subject for post-processing
+	 * @param shouldPostProcess whether the bean is subject to post-processing
 	 * @return the object obtained from the FactoryBean
 	 * @throws BeanCreationException if FactoryBean object creation failed
 	 * @see org.springframework.beans.factory.FactoryBean#getObject()
@@ -100,14 +100,40 @@ public abstract class FactoryBeanRegistrySupport extends DefaultSingletonBeanReg
 			synchronized (getSingletonMutex()) {
 				Object object = this.factoryBeanObjectCache.get(beanName);
 				if (object == null) {
-					object = doGetObjectFromFactoryBean(factory, beanName, shouldPostProcess);
-					this.factoryBeanObjectCache.put(beanName, (object != null ? object : NULL_OBJECT));
+					object = doGetObjectFromFactoryBean(factory, beanName);
+					// Only post-process and store if not put there already during getObject() call above
+					// (e.g. because of circular reference processing triggered by custom getBean calls)
+					Object alreadyThere = this.factoryBeanObjectCache.get(beanName);
+					if (alreadyThere != null) {
+						object = alreadyThere;
+					}
+					else {
+						if (object != null && shouldPostProcess) {
+							try {
+								object = postProcessObjectFromFactoryBean(object, beanName);
+							}
+							catch (Throwable ex) {
+								throw new BeanCreationException(beanName,
+										"Post-processing of FactoryBean's singleton object failed", ex);
+							}
+						}
+						this.factoryBeanObjectCache.put(beanName, (object != null ? object : NULL_OBJECT));
+					}
 				}
 				return (object != NULL_OBJECT ? object : null);
 			}
 		}
 		else {
-			return doGetObjectFromFactoryBean(factory, beanName, shouldPostProcess);
+			Object object = doGetObjectFromFactoryBean(factory, beanName);
+			if (object != null && shouldPostProcess) {
+				try {
+					object = postProcessObjectFromFactoryBean(object, beanName);
+				}
+				catch (Throwable ex) {
+					throw new BeanCreationException(beanName, "Post-processing of FactoryBean's object failed", ex);
+				}
+			}
+			return object;
 		}
 	}
 
@@ -115,13 +141,11 @@ public abstract class FactoryBeanRegistrySupport extends DefaultSingletonBeanReg
 	 * Obtain an object to expose from the given FactoryBean.
 	 * @param factory the FactoryBean instance
 	 * @param beanName the name of the bean
-	 * @param shouldPostProcess whether the bean is subject for post-processing
 	 * @return the object obtained from the FactoryBean
 	 * @throws BeanCreationException if FactoryBean object creation failed
 	 * @see org.springframework.beans.factory.FactoryBean#getObject()
 	 */
-	private Object doGetObjectFromFactoryBean(
-			final FactoryBean<?> factory, final String beanName, final boolean shouldPostProcess)
+	private Object doGetObjectFromFactoryBean(final FactoryBean<?> factory, final String beanName)
 			throws BeanCreationException {
 
 		Object object;
@@ -151,23 +175,12 @@ public abstract class FactoryBeanRegistrySupport extends DefaultSingletonBeanReg
 			throw new BeanCreationException(beanName, "FactoryBean threw exception on object creation", ex);
 		}
 
-
 		// Do not accept a null value for a FactoryBean that's not fully
 		// initialized yet: Many FactoryBeans just return null then.
 		if (object == null && isSingletonCurrentlyInCreation(beanName)) {
 			throw new BeanCurrentlyInCreationException(
 					beanName, "FactoryBean which is currently in creation returned null from getObject");
 		}
-
-		if (object != null && shouldPostProcess) {
-			try {
-				object = postProcessObjectFromFactoryBean(object, beanName);
-			}
-			catch (Throwable ex) {
-				throw new BeanCreationException(beanName, "Post-processing of the FactoryBean's object failed", ex);
-			}
-		}
-
 		return object;
 	}
 

spring-beans/src/test/java/org/springframework/beans/factory/FactoryBeanTests-circular.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+   xsi:schemaLocation="http://www.springframework.org/schema/beans
+                       http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
+
+   <bean id="bean1" class="org.springframework.beans.factory.FactoryBeanTests$PassThroughFactoryBean" primary="true">
+      <constructor-arg value="org.springframework.beans.factory.FactoryBeanTests$BeanImpl1"/>
+      <property name="instanceName" value="beanImpl1"/>
+   </bean>
+
+   <bean id="beanImpl1" class="org.springframework.beans.factory.FactoryBeanTests$BeanImpl1">
+      <property name="impl2" ref="bean2"/>
+   </bean>
+
+   <bean id="bean2" class="org.springframework.beans.factory.FactoryBeanTests$PassThroughFactoryBean" primary="true">
+      <constructor-arg value="org.springframework.beans.factory.FactoryBeanTests$BeanImpl2"/>
+      <property name="instanceName" value="beanImpl2"/>
+   </bean>
+
+   <bean id="beanImpl2" class="org.springframework.beans.factory.FactoryBeanTests$BeanImpl2">
+      <property name="impl1" ref="bean1"/>
+   </bean>
+
+</beans>

spring-beans/src/test/java/org/springframework/beans/factory/FactoryBeanTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,19 +16,24 @@
 
 package org.springframework.beans.factory;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.springframework.tests.TestResourceUtils.qualifiedResource;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import org.junit.Test;
+
+import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
+import org.springframework.beans.factory.config.BeanPostProcessor;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 import org.springframework.core.io.Resource;
 import org.springframework.stereotype.Component;
 import org.springframework.util.Assert;
 
+import static org.junit.Assert.*;
+import static org.springframework.tests.TestResourceUtils.*;
+
 /**
  * @author Rob Harrop
  * @author Juergen Hoeller
@@ -40,6 +45,7 @@ public final class FactoryBeanTests {
 	private static final Resource RETURNS_NULL_CONTEXT = qualifiedResource(CLASS, "returnsNull.xml");
 	private static final Resource WITH_AUTOWIRING_CONTEXT = qualifiedResource(CLASS, "withAutowiring.xml");
 	private static final Resource ABSTRACT_CONTEXT = qualifiedResource(CLASS, "abstract.xml");
+	private static final Resource CIRCULAR_CONTEXT = qualifiedResource(CLASS, "circular.xml");
 
 	@Test
 	public void testFactoryBeanReturnsNull() throws Exception {
@@ -96,6 +102,23 @@ public final class FactoryBeanTests {
 		factory.getBeansOfType(AbstractFactoryBean.class);
 	}
 
+	@Test
+	public void testCircularReferenceWithPostProcessor() {
+		DefaultListableBeanFactory factory = new DefaultListableBeanFactory();
+		new XmlBeanDefinitionReader(factory).loadBeanDefinitions(CIRCULAR_CONTEXT);
+
+		CountingPostProcessor counter = new CountingPostProcessor();
+		factory.addBeanPostProcessor(counter);
+
+		BeanImpl1 impl1 = factory.getBean(BeanImpl1.class);
+		assertNotNull(impl1);
+		assertNotNull(impl1.getImpl2());
+		assertNotNull(impl1.getImpl2());
+		assertSame(impl1, impl1.getImpl2().getImpl1());
+		assertEquals(1, counter.getCount("bean1"));
+		assertEquals(1, counter.getCount("bean2"));
+	}
+
 
 	public static class NullReturningFactoryBean implements FactoryBean<Object> {
 
@@ -193,7 +216,114 @@ public final class FactoryBeanTests {
 		}
 	}
 
+
 	public abstract static class AbstractFactoryBean implements FactoryBean<Object> {
 	}
 
+
+	public static class PassThroughFactoryBean<T> implements FactoryBean<T>, BeanFactoryAware {
+
+		private Class<T> type;
+
+		private String instanceName;
+
+		private BeanFactory beanFactory;
+
+		private T instance;
+
+		public PassThroughFactoryBean(Class<T> type) {
+			this.type = type;
+		}
+
+		public void setInstanceName(String instanceName) {
+			this.instanceName = instanceName;
+		}
+		@Override
+		public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
+			this.beanFactory = beanFactory;
+		}
+
+
+		@Override
+		public T getObject() {
+			if (instance == null) {
+				instance = beanFactory.getBean(instanceName, type);
+			}
+			return instance;
+		}
+
+		@Override
+		public Class<?> getObjectType() {
+			return type;
+		}
+
+		@Override
+		public boolean isSingleton() {
+			return true;
+		}
+	}
+
+
+	public static class CountingPostProcessor implements BeanPostProcessor {
+
+		private final Map<String, AtomicInteger> count = new HashMap<String, AtomicInteger>();
+
+		@Override
+		public Object postProcessBeforeInitialization(Object bean, String beanName) {
+			return bean;
+		}
+
+		@Override
+		public Object postProcessAfterInitialization(Object bean, String beanName) {
+			if (bean instanceof FactoryBean) {
+				return bean;
+			}
+			AtomicInteger c = count.get(beanName);
+			if (c == null) {
+				c = new AtomicInteger(0);
+				count.put(beanName, c);
+			}
+			c.incrementAndGet();
+			return bean;
+		}
+
+		public int getCount(String beanName) {
+			AtomicInteger c = count.get(beanName);
+			if (c != null) {
+				return c.intValue();
+			}
+			else {
+				return 0;
+			}
+		}
+	}
+
+
+	public static class BeanImpl1 {
+
+		private BeanImpl2 impl2;
+
+		public BeanImpl2 getImpl2() {
+			return impl2;
+		}
+
+		public void setImpl2(BeanImpl2 impl2) {
+			this.impl2 = impl2;
+		}
+	}
+
+
+	public static class BeanImpl2 {
+
+		private BeanImpl1 impl1;
+
+		public BeanImpl1 getImpl1() {
+			return impl1;
+		}
+
+		public void setImpl1(BeanImpl1 impl1) {
+			this.impl1 = impl1;
+		}
+	}
+
 }