WELD-001456: Argument resolvedBean must not be null?

[ljnelson]

Hello; I'm using Weld 3.0.0 Alpha17 (using it in a unit test, so Weld SE, if it matters).

I have a @Produces method annotated like this:

@Produces

@Dependent

@Foo

public String getFoo(final InjectionPoint ip) {

   // go get a relevant foo, or not

  return null; // this is permitted if the producer method is annotated with @Dependent, right?

}

When I do something like this:

public class Frob {

   @Inject

   public Frob(@Foo("argle") final String foo) {

     // note: @Foo is a qualifier; its value() element is annotated with @Nonbinding

     super();

   }

}

...the injection fails with the following partial stack:

org.jboss.weld.exceptions.IllegalArgumentException: WELD-001456: Argument resolvedBean must not be null

  at org.jboss.weld.util.Preconditions.checkArgumentNotNull(Preconditions.java:40)

  at org.jboss.weld.manager.BeanManagerImpl.getInjectableReference(BeanManagerImpl.java:744)

  at org.jboss.weld.injection.ParameterInjectionPointImpl.getValueToInject(ParameterInjectionPointImpl.java:76)

  at org.jboss.weld.injection.ConstructorInjectionPoint.getParameterValues(ConstructorInjectionPoint.java:150)

  at org.jboss.weld.injection.ConstructorInjectionPoint.newInstance(ConstructorInjectionPoint.java:75)

  at org.jboss.weld.injection.producer.AbstractInstantiator.newInstance(AbstractInstantiator.java:28)

  at org.jboss.weld.injection.producer.BasicInjectionTarget.produce(BasicInjectionTarget.java:112)

  at org.jboss.weld.injection.producer.BeanInjectionTarget.produce(BeanInjectionTarget.java:180)

I'm sure I have missed something obvious.  What?

[tremes]

Hi Laird,

Yes your producer can return null (must be Dependent scope). But when Weld performs injection it checks whether it has "something" to inject. In other words you can't inject null value due to Weld validation (which is fully reasonable) - see core/Preconditions.java at master · weld/core · GitHub

[mkouba]

Hi Laird,

this is weird. You should be able to "inject null" in this case. Could you share your unit test somewhere (github)?

[mkouba]

FYI I've just tried to reproduce the problem with no success. So we will definitely need your test .

[tremes]

Ok sorry I didn't realize that it cannot find the corresponding bean. Then it's little bit weird so some test or at least complete class definition would be definitely helpful.

[ljnelson]

I am going to chalk this up to pilot error as I cannot now reproduce the

problem. If this is not a clear case of "Oh, you forgot to initialize the

frobnicator", then I am sure I was just moving too fast. These are usually

signs that one should take a deep breath and go have a cup of tea for a

bit.  

Best,

Laird