ConfigurationClassPostProcessor skips pre-processed bean definitions now (avoiding side effects in case of multiple CCPPs)

Issue: SPR-11858
(cherry picked from commit b625512)

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassPostProcessor.java

@@ -271,7 +271,13 @@ public class ConfigurationClassPostProcessor implements BeanDefinitionRegistryPo
 		Set<BeanDefinitionHolder> configCandidates = new LinkedHashSet<BeanDefinitionHolder>();
 		for (String beanName : registry.getBeanDefinitionNames()) {
 			BeanDefinition beanDef = registry.getBeanDefinition(beanName);
-			if (ConfigurationClassUtils.checkConfigurationClassCandidate(beanDef, this.metadataReaderFactory)) {
+			if (ConfigurationClassUtils.isFullConfigurationClass(beanDef) ||
+					ConfigurationClassUtils.isLiteConfigurationClass(beanDef)) {
+				if (logger.isDebugEnabled()) {
+					logger.debug("Bean definition has already been processed as a configuration class: " + beanDef);
+				}
+			}
+			else if (ConfigurationClassUtils.checkConfigurationClassCandidate(beanDef, this.metadataReaderFactory)) {
 				configCandidates.add(new BeanDefinitionHolder(beanDef, beanName));
 			}
 		}
@@ -443,6 +449,6 @@ public class ConfigurationClassPostProcessor implements BeanDefinitionRegistryPo
 			}
 			return pvs;
 		}
-
 	}
+
 }

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassUtils.java

@@ -139,4 +139,12 @@ abstract class ConfigurationClassUtils {
 		return CONFIGURATION_CLASS_FULL.equals(beanDef.getAttribute(CONFIGURATION_CLASS_ATTRIBUTE));
 	}
 
+	/**
+	 * Determine whether the given bean definition indicates a lite {@code @Configuration}
+	 * class, through checking {@link #checkConfigurationClassCandidate}'s metadata marker.
+	 */
+	public static boolean isLiteConfigurationClass(BeanDefinition beanDef) {
+		return CONFIGURATION_CLASS_LITE.equals(beanDef.getAttribute(CONFIGURATION_CLASS_ATTRIBUTE));
+	}
+
 }

spring-context/src/test/java/org/springframework/context/annotation/configuration/ImportXmlConfig-context.xml

@@ -15,4 +15,7 @@
 		</property>
 	</bean>
 
+	<!-- should not cause infinite loop (SPR-11858) but rather simply be ignored -->
+	<bean class="org.springframework.context.annotation.ConfigurationClassPostProcessor"/>
+
 </beans>