Isolated circular import detection for scanned configuration classes

Issue: SPR-14517
(cherry picked from commit 703c37e)

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

@@ -134,7 +134,7 @@ class ConfigurationClassParser {
 
 	private final List<String> propertySourceNames = new ArrayList<String>();
 
-	private final ImportStack importStack = new ImportStack();
+	private ImportStack importStack = new ImportStack();
 
 	private List<DeferredImportSelectorHolder> deferredImportSelectors;
 
@@ -269,7 +269,16 @@ class ConfigurationClassParser {
 			// Check the set of scanned definitions for any further config classes and parse recursively if necessary
 			for (BeanDefinitionHolder holder : scannedBeanDefinitions) {
 				if (ConfigurationClassUtils.checkConfigurationClassCandidate(holder.getBeanDefinition(), this.metadataReaderFactory)) {
-					parse(holder.getBeanDefinition().getBeanClassName(), holder.getBeanName());
+					// Provide isolated circular import detection for scanned classes,
+					// since the initial registration did not come explicitly.
+					ImportStack previousStack = this.importStack;
+					this.importStack = new ImportStack();
+					try {
+						parse(holder.getBeanDefinition().getBeanClassName(), holder.getBeanName());
+					}
+					finally {
+						this.importStack = previousStack;
+					}
 				}
 			}
 		}

spring-context/src/test/java/org/springframework/context/annotation/ComponentScanAndImportAnnotationInteractionTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -19,6 +19,7 @@ package org.springframework.context.annotation;
 import org.junit.Test;
 
 import org.springframework.beans.factory.support.RootBeanDefinition;
+import org.springframework.context.annotation.componentscan.importing.ImportingConfig;
 import org.springframework.context.annotation.componentscan.simple.SimpleComponent;
 
 /**
@@ -58,7 +59,7 @@ public class ComponentScanAndImportAnnotationInteractionTests {
 	@Test
 	public void componentScanViaImportUsingAsm() {
 		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
-		ctx.registerBeanDefinition("config4", new RootBeanDefinition(Config3.class.getName()));
+		ctx.registerBeanDefinition("config", new RootBeanDefinition(Config3.class.getName()));
 		ctx.refresh();
 		ctx.getBean(SimpleComponent.class);
 	}
@@ -71,6 +72,14 @@ public class ComponentScanAndImportAnnotationInteractionTests {
 		ctx.getBean(SimpleComponent.class);
 	}
 
+	@Test
+	public void circularImportViaComponentScan() {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+		ctx.registerBeanDefinition("config", new RootBeanDefinition(ImportingConfig.class.getName()));
+		ctx.refresh();
+		ctx.getBean(SimpleComponent.class);
+	}
+
 
 	@ComponentScan("org.springframework.context.annotation.componentscan.simple")
 	static final class Config1 {
@@ -87,7 +96,8 @@ public class ComponentScanAndImportAnnotationInteractionTests {
 	}
 
 
-	@ComponentScan("org.springframework.context.annotation.componentscan.simple")
+	@ComponentScan({"org.springframework.context.annotation.componentscan.simple",
+			"org.springframework.context.annotation.componentscan.importing"})
 	public static final class ImportedConfig {
 	}