Detect depends-on cycles and throw proper exception

Issue: SPR-7966

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

@@ -286,8 +286,12 @@ public abstract class AbstractBeanFactory extends FactoryBeanRegistrySupport imp
 				String[] dependsOn = mbd.getDependsOn();
 				if (dependsOn != null) {
 					for (String dependsOnBean : dependsOn) {
-						getBean(dependsOnBean);
+						if (isDependent(beanName, dependsOnBean)) {
+							throw new BeanCreationException("Circular depends-on relationship between '" +
+									beanName + "' and '" + dependsOnBean + "'");
+						}
 						registerDependentBean(dependsOnBean, beanName);
+						getBean(dependsOnBean);
 					}
 				}
 

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

@@ -412,6 +412,28 @@ public class DefaultSingletonBeanRegistry extends SimpleAliasRegistry implements
 		}
 	}
 
+	/**
+	 * Determine whether the specified dependent bean has been registered as
+	 * dependent on the given bean or on any of its transitive dependencies.
+	 * @param beanName the name of the bean to check
+	 * @param dependentBeanName the name of the dependent bean
+	 */
+	protected boolean isDependent(String beanName, String dependentBeanName) {
+		Set<String> dependentBeans = this.dependentBeanMap.get(beanName);
+		if (dependentBeans == null) {
+			return false;
+		}
+		if (dependentBeans.contains(dependentBeanName)) {
+			return true;
+		}
+		for (String transitiveDependency : dependentBeans) {
+			if (isDependent(transitiveDependency, dependentBeanName)) {
+				return true;
+			}
+		}
+		return false;
+	}
+
 	/**
 	 * Determine whether a dependent bean has been registered for the given name.
 	 * @param beanName the name of the bean to check

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

@@ -1219,8 +1219,8 @@ public class DefaultListableBeanFactoryTests {
 		}
 		catch (UnsatisfiedDependencyException ex) {
 			// expected
-			assertTrue(ex.getMessage().indexOf("rod") != -1);
-			assertTrue(ex.getMessage().indexOf("rod2") != -1);
+			assertTrue(ex.getMessage().contains("rod"));
+			assertTrue(ex.getMessage().contains("rod2"));
 		}
 	}
 
@@ -1290,6 +1290,51 @@ public class DefaultListableBeanFactoryTests {
 		assertNull(bean.getSpouse());
 	}
 
+	@Test
+	public void testDependsOnCycle() {
+		DefaultListableBeanFactory lbf = new DefaultListableBeanFactory();
+		RootBeanDefinition bd1 = new RootBeanDefinition(TestBean.class);
+		bd1.setDependsOn(new String[] {"tb2"});
+		lbf.registerBeanDefinition("tb1", bd1);
+		RootBeanDefinition bd2 = new RootBeanDefinition(TestBean.class);
+		bd2.setDependsOn(new String[] {"tb1"});
+		lbf.registerBeanDefinition("tb2", bd2);
+		try {
+			lbf.preInstantiateSingletons();
+			fail("Should have thrown BeanCreationException");
+		}
+		catch (BeanCreationException ex) {
+			// expected
+			assertTrue(ex.getMessage().contains("Circular"));
+			assertTrue(ex.getMessage().contains("'tb2'"));
+			assertTrue(ex.getMessage().contains("'tb1'"));
+		}
+	}
+
+	@Test
+	public void testImplicitDependsOnCycle() {
+		DefaultListableBeanFactory lbf = new DefaultListableBeanFactory();
+		RootBeanDefinition bd1 = new RootBeanDefinition(TestBean.class);
+		bd1.setDependsOn(new String[] {"tb2"});
+		lbf.registerBeanDefinition("tb1", bd1);
+		RootBeanDefinition bd2 = new RootBeanDefinition(TestBean.class);
+		bd2.setDependsOn(new String[] {"tb3"});
+		lbf.registerBeanDefinition("tb2", bd2);
+		RootBeanDefinition bd3 = new RootBeanDefinition(TestBean.class);
+		bd3.setDependsOn(new String[] {"tb1"});
+		lbf.registerBeanDefinition("tb3", bd3);
+		try {
+			lbf.preInstantiateSingletons();
+			fail("Should have thrown BeanCreationException");
+		}
+		catch (BeanCreationException ex) {
+			// expected
+			assertTrue(ex.getMessage().contains("Circular"));
+			assertTrue(ex.getMessage().contains("'tb3'"));
+			assertTrue(ex.getMessage().contains("'tb1'"));
+		}
+	}
+
 	@Test(expected=NoSuchBeanDefinitionException.class)
 	public void testGetBeanByTypeWithNoneFound() {
 		DefaultListableBeanFactory lbf = new DefaultListableBeanFactory();
@@ -2174,7 +2219,7 @@ public class DefaultListableBeanFactoryTests {
 		AbstractBeanDefinition beanDefinition = builder.getBeanDefinition();
 		beanDefinition.setScope("he put himself so low could hardly look me in the face");
 
-		final DefaultListableBeanFactory factory = new DefaultListableBeanFactory();
+		DefaultListableBeanFactory factory = new DefaultListableBeanFactory();
 		factory.registerBeanDefinition("testBean", beanDefinition);
 		factory.getBean("testBean");
 	}
@@ -2186,8 +2231,7 @@ public class DefaultListableBeanFactoryTests {
 		RootBeanDefinition parent = new RootBeanDefinition();
 		parent.setScope(RootBeanDefinition.SCOPE_PROTOTYPE);
 
-		AbstractBeanDefinition child = BeanDefinitionBuilder
-				.childBeanDefinition("parent").getBeanDefinition();
+		AbstractBeanDefinition child = BeanDefinitionBuilder.childBeanDefinition("parent").getBeanDefinition();
 		child.setBeanClass(TestBean.class);
 		child.setScope(theChildScope);