Regression in 6.2.3: No unique bean available for injection point with unresolvable generics

[ML-Marco]

Autowiring does not find a suitable candidate in 6.2.3 any more. Throws an exception on startup. This used to work with all previous versions, including 6.2.2.

Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'spring.PaymentCreator<spring.Payment, spring.PaymentCreatorParameter<spring.Payment>>' available: expected single matching bean but found 2: bankTransferCreator,electronicCashPaymentCreator

Reproducer: bug.zip

[sbrannen]

Thanks for raising the issue, @ML-Marco.

I have confirmed that your sample application works with 6.1.17 but fails with 6.2.3 and 6.2.4-SNAPSHOT with the following exception.

Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'spring.PaymentCreator<spring.Payment, spring.PaymentCreatorParameter<spring.Payment>>' available: expected single matching bean but found 2: bankTransferCreator,electronicCashPaymentCreator
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveNotUnique(DependencyDescriptor.java:218) ~[spring-beans-6.2.4-SNAPSHOT.jar:6.2.4-SNAPSHOT]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1644) ~[spring-beans-6.2.4-SNAPSHOT.jar:6.2.4-SNAPSHOT]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1555) ~[spring-beans-6.2.4-SNAPSHOT.jar:6.2.4-SNAPSHOT]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:785) ~[spring-beans-6.2.4-SNAPSHOT.jar:6.2.4-SNAPSHOT]
	... 35 more

We'll look into it.

[ML-Marco]

@sbrannen It doesn't fail with 6.2.2. This might help to find the commit that broke it.

[sbrannen]

@sbrannen It also fails with 6.2.2. This might help to find the commit that broke it.

I apologize: I was unclear.

In my tests, it fails against 6.2.0 through 6.2.4-SNAPSHOT.

So, it appears that the regression was introduced during the 6.2 milestone/RC phases.

[jhoeller]

It's worth noting that the algorithm actually finds two candidates rather than none, so it's a not-unique scenario where it ends up with two candidates which are considered equivalent in terms of the type match. From an initial glance at the repro project, it's not clear to me which one of the two beans is actually meant to be injected there (i.e. which one got injected with the algorithm as it was in 6.1) since both of them look like a match to me. Any insight in terms of the intended design there from your side, @ML-Marco?

[ML-Marco]

@jhoeller I corrected my statement above. The reproducer does work with 6.2.2 and fails with 6.2.3.
I guess the one that was found in version 6.2.2 which is the base class (PaymentCreator) and not one of its subclasses.

[sbrannen]

@jhoeller I corrected my statement above. The reproducer does work with 6.2.2 and fails with 6.2.3.

Oops. I need to correct my above statement as well. I must have had an issue with caching or something. Here are my findings.

• 6.1.17: works
• 6.2.0: fails
• 6.2.1: works
• 6.2.2: works
• 6.2.3: fails
• 6.2.4-SNAPSHOT: fails

And when I say "works", I simply mean it did not throw a NoUniqueBeanDefinitionException at startup.