Merged bean definitions are now cached early and selectively evicted after post-processing and before actual bean creation

Issue: SPR-12236

spring-beans/src/main/java/org/springframework/beans/factory/config/ConfigurableListableBeanFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -121,6 +121,18 @@ public interface ConfigurableListableBeanFactory
 	 */
 	Iterator<String> getBeanNamesIterator();
 
+	/**
+	 * Clear the merged bean definition cache, removing entries for beans
+	 * which are not considered eligible for full metadata caching yet.
+	 * <p>Typically triggered after changes to the original bean definitions,
+	 * e.g. after applying a {@link BeanFactoryPostProcessor}. Note that metadata
+	 * for beans which have already been created at this point will be kept around.
+	 * @since 4.2
+	 * @see #getBeanDefinition
+	 * @see #getMergedBeanDefinition
+	 */
+	void clearMetadataCache();
+
 	/**
 	 * Freeze all bean definitions, signalling that the registered bean definitions
 	 * will not be modified or post-processed any further.

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

@@ -27,6 +27,7 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.LinkedList;
@@ -1262,7 +1263,7 @@ public abstract class AbstractBeanFactory extends FactoryBeanRegistrySupport imp
 
 				// Only cache the merged bean definition if we're already about to create an
 				// instance of the bean, or at least have already created an instance before.
-				if (containingBd == null && isCacheBeanMetadata() && isBeanEligibleForMetadataCaching(beanName)) {
+				if (containingBd == null && isCacheBeanMetadata()) {
 					this.mergedBeanDefinitions.put(beanName, mbd);
 				}
 			}
@@ -1296,6 +1297,23 @@ public abstract class AbstractBeanFactory extends FactoryBeanRegistrySupport imp
 		this.mergedBeanDefinitions.remove(beanName);
 	}
 
+	/**
+	 * Clear the merged bean definition cache, removing entries for beans
+	 * which are not considered eligible for full metadata caching yet.
+	 * <p>Typically triggered after changes to the original bean definitions,
+	 * e.g. after applying a {@code BeanFactoryPostProcessor}. Note that metadata
+	 * for beans which have already been created at this point will be kept around.
+	 * @since 4.2
+	 */
+	public void clearMetadataCache() {
+		Iterator<String> mergedBeans = this.mergedBeanDefinitions.keySet().iterator();
+		while (mergedBeans.hasNext()) {
+			if (!isBeanEligibleForMetadataCaching(mergedBeans.next())) {
+				mergedBeans.remove();
+			}
+		}
+	}
+
 	/**
 	 * Resolve the bean class for the specified bean definition,
 	 * resolving a bean class name into a Class reference (if necessary)
@@ -1475,6 +1493,10 @@ public abstract class AbstractBeanFactory extends FactoryBeanRegistrySupport imp
 	protected void markBeanAsCreated(String beanName) {
 		if (!this.alreadyCreated.contains(beanName)) {
 			this.alreadyCreated.add(beanName);
+
+			// Let the bean definition get re-merged now that we're actually creating
+			// the bean... just in case some of its metadata changed in the meantime.
+			clearMergedBeanDefinition(beanName);
 		}
 	}
 

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

@@ -708,6 +708,12 @@ public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFacto
 		return iterator;
 	}
 
+	@Override
+	public void clearMetadataCache() {
+		super.clearMetadataCache();
+		clearByTypeCache();
+	}
+
 	@Override
 	public void freezeConfiguration() {
 		this.configurationFrozen = true;

spring-context/src/main/java/org/springframework/context/support/PostProcessorRegistrationDelegate.java

@@ -179,6 +179,10 @@ class PostProcessorRegistrationDelegate {
 			nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
 		}
 		invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);
+
+		// Clear cached merged bean definitions since the post-processors might have
+		// modified the original metadata, e.g. replacing placeholders in values...
+		beanFactory.clearMetadataCache();
 	}
 
 	public static void registerBeanPostProcessors(