Alias chaining does not work with @Qualifier and @Autowired [SPR-5501]

[spring-projects-issues]

James Hood opened SPR-5501 and commented

Based on #7435, it seems that the following JUnit 4 test should work (spring context below the code):

package com.uprr.app.ngt;

import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.is;
import static org.junit.Assert.assertThat;

import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.AbstractJUnit4SpringContextTests;

@ContextConfiguration
public class AliasTest extends AbstractJUnit4SpringContextTests {

  private static final String expected = "the_value";
  
  @Autowired
  @Qualifier("alias1")
  private String alias1;
  
  @Autowired
  @Qualifier("alias2")
  private String alias2;
  
  @Autowired
  @Qualifier("realBean")
  private String realBean;  
  
  @Test
  public void testAutowiredAlias() throws Exception {
    assertThat(alias1, is(equalTo(expected)));
  }
  
  @Test
  public void testAutowiredAliasOfAlias() throws Exception {
    assertThat(alias2, is(equalTo(expected)));
  }
  
  @Test
  public void testAutowiredRealBean() throws Exception {
    assertThat(realBean, is(equalTo(expected)));
  }

  public void setAlias1(String alias1) {
    this.alias1 = alias1;
  }

  public void setAlias2(String alias2) {
    this.alias2 = alias2;
  }

  public void setRealBean(String realBean) {
    this.realBean = realBean;
  }  
  
}

Spring context:

<?xml version="1.0" encoding="UTF-8"?>
<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-2.5.xsd">
  
  <bean id="realBean" class="java.lang.String">
    <constructor-arg value="the_value"/>
  </bean>
  
  <alias alias="alias1" name="realBean"/>
  
  <alias alias="alias2" name="alias1"/>

</beans>

But for me it fails with the following:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.uprr.app.ngt.AliasTest': Autowiring of fields failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private java.lang.String com.uprr.app.ngt.AliasTest.alias2; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [java.lang.String] is defined: Unsatisfied dependency of type [class java.lang.String]: expected at least 1 matching bean
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessAfterInstantiation(AutowiredAnnotationBeanPostProcessor.java:243)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:957)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireBeanProperties(AbstractAutowireCapableBeanFactory.java:329)
	at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:110)
	at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:75)
	at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:255)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:93)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.invokeTestMethod(SpringJUnit4ClassRunner.java:130)
	at org.junit.internal.runners.JUnit4ClassRunner.runMethods(JUnit4ClassRunner.java:51)
	at org.junit.internal.runners.JUnit4ClassRunner$1.run(JUnit4ClassRunner.java:44)
	at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:27)
	at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:37)
	at org.junit.internal.runners.JUnit4ClassRunner.run(JUnit4ClassRunner.java:42)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:38)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:460)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:673)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:386)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private java.lang.String com.uprr.app.ngt.AliasTest.alias2; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [java.lang.String] is defined: Unsatisfied dependency of type [class java.lang.String]: expected at least 1 matching bean
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:435)
	at org.springframework.beans.factory.annotation.InjectionMetadata.injectFields(InjectionMetadata.java:105)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessAfterInstantiation(AutowiredAnnotationBeanPostProcessor.java:240)
	... 18 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [java.lang.String] is defined: Unsatisfied dependency of type [class java.lang.String]: expected at least 1 matching bean
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:613)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:412)
	... 20 more

If the value of the name attribute of the alias2 alias is changed to be realBean, all three tests pass.

---

Affects: 2.5.5

[spring-projects-issues]

Juergen Hoeller commented

Thanks for pointing this out! Indeed, we should support chained aliases for @Qualifier value matching as well. Fixed as of 3.0 M2.

Juergen