Autowiring of a generic type produced by a factory bean fails after AOT processing

[wilkinsona]

Affects: 6.0.0-RC2

We found this problem when testing Spring Boot's JacksonTester support but I believe it's a general AOT problem to do with factory beans that produce a generic type. Here's a small sample that reproduces the problem:

factory-bean-problem.zip

./gradlew test should result in two failures:

> Task :test FAILED

FactoryBeanProblemApplicationTests > contextLoads() FAILED
    org.springframework.beans.factory.UnsatisfiedDependencyException at AutowiredAnnotationBeanPostProcessor.java:744
        Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException at DefaultListableBeanFactory.java:1782

MinimalReproductionTests > aotConfig() FAILED
    org.springframework.beans.factory.UnsatisfiedDependencyException at MinimalReproductionTests.java:46
        Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException at MinimalReproductionTests.java:46

The first reproduces the problem that we've seen in Spring Boot. If you edit build.gradle to comment out the setting of the spring.aot.enabled system property and run ./gradlew test again, contextLoads() should pass. The second is an attempt to reproduce the problem in a minimal (and slightly simplified) manner. It doesn't involve Boot or the Test Framework at all.

From what I have seen in the debugger, the behavior diverges in GenericTypeAwareAutowireCandidateResolver.checkGenericTypeMatch(BeanDefinitionHolder, DependencyDescriptor). In the Java config case, the target type is determined via a BeanFactory.getType call:

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

Lines 107 to 110 in 997dd3e

	if (targetType == null) {
	// Regular case: straight bean instance, with BeanFactory available.
	if (this.beanFactory != null) {
	Class<?> beanType = this.beanFactory.getType(bdHolder.getBeanName());

This is sufficient for the result of the check to be true and for autowiring to succeed.

In the AOT-processed case, the target type is available from the bean definition:

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

Line 90 in 997dd3e

targetType = rbd.targetType;

As a result, the getType call on the bean factory never happens. The result of the check is false and autowiring fails.

[sdeleuze]

I tentatively add this one for 6.0 GA since that breaking some propular use cases.

[wilkinsona]

Things have improved, but the problem isn't fully resolved. While the slightly simplified reproducer now passes, the other test in the sample still fails:

> Task :test FAILED

FactoryBeanProblemApplicationTests > contextLoads() FAILED
    org.springframework.beans.factory.UnsatisfiedDependencyException at AutowiredAnnotationBeanPostProcessor.java:744
        Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException at DefaultListableBeanFactory.java:1812

3 tests completed, 1 failed

FAILURE: Build failed with an exception.

As before, this test passes when AOT processing is not enabled.