ArC: improve support for active/inactive beans

[Ladicek]

Description

We now have initial support for active/inactive beans in ArC, see #41810. Here are some ideas that would make that better:

We could add an @Active qualifier to inject only active beans into a List, similarly to @All. Alternatively, we could add something like this to InjectableInstance:

default List<T> listActive() {
    return handlesStream().filter(h -> h.getBean().isActive()).map(InstanceHandle::get).toList();
}

• Done in ArC: add InjectableInstance.getActive() and listActive() #43803

We might need to add the ability to use an exception as a cause of an inactive bean (in ActiveResult).

We might want to modify Instance.isUnsatisfied()/isAmbiguous() to remove inactive beans. There was also an idea to make inactive beans suppressed, but we cannot do that, because we sometimes need to access metadata of inactive beans through Instance (notably, to decide if some other bean is active or inactive, and use their ActiveResult as a cause). Perhaps this reason also precludes the modification of isUnsatisfied()/isAmbiguous(), need to think more about it.

We should add active/inactive support to ArC dev UI.

• Done in ArC: inactive beans in dev UI #43781

Not sure if there's more.

Implementation ideas

No response

[quarkus-bot]

/cc @manovotn (arc), @mkouba (arc)

[Ladicek]

Also CC @yrodiere

[manovotn]

Not sure if there's more.

@Ladicek we could also modify Dev UI to mark beans that are possibly inactive in your app.

[Ladicek]

I actually think we shouldn't modify InjectableInstance.isUnsatisfied()/isAmbiguous(), because that would make the result of these methods inconsistent with the behavior of get()/iterator()/etc.

This means the only unfinished thing from the list is supporting an exception as an ActiveResult cause, but that's not a terribly big deal. And perhaps some more user-friendly way of obtaining only active beans, but we need more feedback to actually consider something.

Therefore, closing this as done.