[weld-dev] Re: BasicInjectionTarget ignores injection points set by portable extension?

I believe that if you replace the original InjectionTarget and change the set of injection points then it's your responsibility to perform the injection for the additional injection points because Weld (the original InjectionTarget) does not have enough information to fulfill this task - after all, the spec is very clear that "Implementations of Producer and InjectionTarget must ensure that the set of injection points returned by getInjectionPoints() are injected by produce() or inject()." [1]. In this particular case, the replacement is the "implementation".

Martin [1] https://jakarta.ee/specifications/cdi/4.1/jakarta-cdi-spec-4.1#injectiont... On 17. 10. 24 10:43, Matej Novotny wrote: > I recall this came up some long time ago as well and while I am still > refreshing my knowledge on this, here are some thoughts. > > > Through some details that I can go into if needed, I can see that > some portion of Weld indeed does recognize my custom injection point. So > in some places in the Weld codebase, my work is recognized, i.e. > getInjectionPoints() is returning something that I have added, that > Weld's internals "see". It makes some sort of validation attempt, or > something, to satisfy it. So far so good. > > IIRC, Weld did recognize these added IPs for the purpose of validation > which is probably the part you noticed. > > > The injection point so added is one of my choosing and it does not > matter why I chose it. It honors the InjectionPoint contract. My > intention is that this is something that CDI should "fill". > > What exactly should CDI do with this injection point in your opinion? > Given a class based beans with some fields (just to keep it simple), you > can modify the set of injection points and add an extra IP of type Foo > that wasn't present before. > You can "honor" the InjectionPoint contract but you can still configure > the IP arbitrarily - you can override a field that's already injected > but you can also make up one. You could use an ordinary method as a > Member and that would never get injected anyway. > Apart from validation which would fail if Foo bean is not resolvable, > what do you gain? No user can put their hands on Foo as there is no > param or field that would really be injected that they can access. > > > However, my InjectionTarget's inject() method, which I have *not* > customized, but merely forwarded to the container-supplied > InjectionTarget, does not respect the Set of InjectionPoints I have > reported, which includes my custom one. I found this strange. I would > have expected its injection mechanism to work on the InjectionPoints I > have reported, and none other. Instead it seems it works only on fields > it has discovered. Or something. (In which case why let portable > extensions modify this area only to ignore them?) > > Frankly speaking, I always found the ability to override IPs for an > injection target very strange and I don't think I saw a use for it that > wasn't at least mostly theoretical. > That being said, I recall there were some implementation issues which > resulted in the current behavior; my guess would be it was the > difficulty of identifying the IP via its Member and making sense of it. > After all, any additional injection might as well be one via overriden > inject(...) method in the same API. > I am still digging through some older issues trying to see if I can find > some notion of why we ended up handling it this way. > > This might also be worth asking on the CDI spec to get more opinions and > possibly eventually a clarification. > But I'll leave that up to you. > > Matej > > On Thu, Oct 17, 2024 at 6:36 AM Laird Nelson <ljnelson(a)gmail.com > <mailto:ljnelson@gmail.com>> wrote: > > It is possible I am doing something wrong. > > I have an observer method in a portable extension that observes > ProcessInjectionTarget events. > > This is in CDI SE in case it ends up mattering. I hope it won't. > > I replace the InjectionTarget via the official, documented, > event.setInjectionTarget(InjectionTarget) by decorating the > InjectionTarget that is reachable from the event. So, for example, > my custom InjectionTarget calls event.getInjectionTarget().dispose() > when dispose() is called on my custom InjectionTarget, and, indeed, > for most of the methods involved. Basic forwarding/delegate stuff. > > In my replacement InjectionTarget, I add an InjectionPoint to the > Set of InjectionPoints reported by the InjectionTarget via its > getInjectionPoints() method. Nothing fancy. > > The injection point so added is one of my choosing and it does not > matter why I chose it. It honors the InjectionPoint contract. My > intention is that this is something that CDI should "fill". > > Through some details that I can go into if needed, I can see that > some portion of Weld indeed does recognize my custom injection > point. So in some places in the Weld codebase, my work is > recognized, i.e. getInjectionPoints() is returning something that I > have added, that Weld's internals "see". It makes some sort of > validation attempt, or something, to satisfy it. So far so good. > > However, my InjectionTarget's inject() method, which I have *not* > customized, but merely forwarded to the container-supplied > InjectionTarget, does not respect the Set of InjectionPoints I have > reported, which includes my custom one. I found this strange. I > would have expected its injection mechanism to work on the > InjectionPoints I have reported, and none other. Instead it seems it > works only on fields it has discovered. Or something. (In which case > why let portable extensions modify this area only to ignore them?) > > Digging deeper, I found that the BasicInjectionTarget (the > "container"-supplied one) passes off injection to something called > an Injector. It passes along "this", which is, among other things, > an InjectionTarget. So far so good, though it is starting to get a > little murky. That is, at least the Injector seems to have the > possibility of calling getInjectionPoints() on the target rather > than deciding it knows best. > > For some reason, and I don't think I care, ultimately, the Injector > is a ResourceInjector. > > In any event, it then proceeds to do injection, but, contrary to my > expectations, it ignores my custom injection points. That is, it > never calls myCustomInjectionTarget.getInjectionPoints() to see what > needs to be injected. See for yourself (note that injectionTarget > (mine, in this case) is never used (well, OK, it is passed to the > InjectionContextImpl, where it seems to be ignored)): > > https://github.com/weld/core/blob/225ced4d3dff4d0df5bf167c4d2374cdce00e55... < https://github.com/weld/core/blob/225ced4d3dff4d0df5bf167c4d2374cdce00e55... > > > Note that this Injector has a reference to the InjectionTarget, but > never seems to call getInjectionPoints() when it is doing injection. > You would think that since portable extensions can replace the > InjectionTarget, it must do this, but it does not. > > What am I missing? If an InjectionTarget's InjectionPoints are never > consulted, why make an InjectionTarget report them in the first > place? Should I file a bug? > > Best, > Laird > _______________________________________________ > weld-dev mailing list -- weld-dev(a)lists.jboss.org > <mailto:weld-dev@lists.jboss.org> > To unsubscribe send an email to weld-dev-leave(a)lists.jboss.org > <mailto:weld-dev-leave@lists.jboss.org> > Privacy Statement: https://www.redhat.com/en/about/privacy-policy > <https://www.redhat.com/en/about/privacy-policy> > List Archives: > https://lists.jboss.org/archives/list/weld-dev@lists.jboss.org/message/EZ... < https://lists.jboss.org/archives/list/weld-dev@lists.jboss.org/message/EZ... > > > > _______________________________________________ > weld-dev mailing list -- weld-dev(a)lists.jboss.org > To unsubscribe send an email to weld-dev-leave(a)lists.jboss.org > Privacy Statement: https://www.redhat.com/en/about/privacy-policy > List Archives: https://lists.jboss.org/archives/list/weld-dev@lists.jboss.org/message/2E... -- Martin Kouba Principal Software Engineer Red Hat, Czech Republic