[cdi-dev] [JBoss JIRA] (CDI-408) bean-discovery-mode="annotated" and Producers/Observers in @Dependent beans

[Jens Schumann (JIRA)]

Jens Schumann created CDI-408:
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             Summary: bean-discovery-mode="annotated" and Producers/Observers in @Dependent beans
                 Key: CDI-408
                 URL: https://issues.jboss.org/browse/CDI-408
             Project: CDI Specification Issues
          Issue Type: Clarification
          Components: Beans
            Reporter: Jens Schumann


Right now bean-discovery-mode="annotated" skips beans that are not annotated with an bean-defining annotation even if they contain an observer method or producer method/field. I would not recommend having (not annotated) @Dependent beans with @Observes or @Produces - I just had them by accident while playing around with Wildfly.

However there are two impacts:

1. Someone might be confused by ignored @Producer's. Not a major issue here, the CDI runtime will report it. We could optionally document the behavior in the spec, so it's clear to everyone. However I think it's inconsistent, since @Produces may contain a scope (and has a default scope too). Therefore I would vote for @Produces support in bean-discovery-mode="annotated". Of course the enclosing class is not a managed bean that may be injected somewhere.

2. Since Observer methods in "not annotated" beans fail silently this can be a major issue for applications, especially if you migrate from CDI 1.0 (CDI 1.0 source code and CDI 1.0 thinking model). Therefore I believe @Observer methods have to be included in bean-discovery-mode="annotated" even if the enclosing bean does not have a bean-defining annotation. Of course the enclosing class is not a managed bean that may be injected somewhere.

I understand that the proposal above might have negative impacts on class scanning performance in bean-discovery-mode="annotated". However silently failing @Observes can be a major cause of defects that have to be treated because of technical and political reasons. Technical - because it may cause bugs. And political - because in my experience many people are still skeptical that CDI events are a trustworthy achievement[1]. Possibly skipped observer methods won't make live easier.

If you believe the proposal would kill the original intent of bean-discovery-mode="annotated" please document the impact for Producers and Observers in the spec and even in the XSD.

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[1] I have trained a couple hundred people in using CDI and CDI events. And every time I have to argument against the uncertainty on event delivery: "How do I know which observers are active?", "Who ensures that event's are delivered?"... I personally LOVE events;)
 
Btw: Which JIRA version is CDI 1.1 Final? 

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