[infinispan-dev] Why JCache embedded has core as provided dependency

[Galder Zamarreño]

What has changed is that Stéphane has made a very good point which I had not realised:

Making core provided dependency means a JCache dependency user needs to add core dependency on top of that, which reduces usability. Core jar is not a provided dependency of JCache, it's a normal dependency. I don't think provided dependencies should be used to get around uber jar dependency issues.

IMO, the bigger usability issue is the fact that uber jars are available as Maven dependencies. Uber jars should just not be distributed as Maven dependencies. They should just be put somewhere else but not in Maven. That'd way we'd avoid the problem in the first place.

In the mean time, I think we should:

* Move back to having normal dependencies for core in JCache (and Spring too, if it applies)
* Go through our examples and avoid using uber jar dependencies.

Then, explore the idea above of not having uber jars as Maven dependencies.

Cheers,
--
Galder Zamarreño
Infinispan, Red Hat

> On 7 Jun 2017, at 12:23, Sebastian Laskawiec <slaskawi at redhat.com> wrote:
> 
> We discussed it number of times, including (but probably not limited to):
> 	• http://lists.jboss.org/pipermail/infinispan-dev/2016-February/016414.html
> 	• http://lists.jboss.org/pipermail/infinispan-dev/2016-March/016490.html
> You might also want to look into the internal lists...
> 
> The biggest question - has anything changed? Do we have any other idea? 
> 
> On Wed, Jun 7, 2017 at 12:05 PM Galder Zamarreño <galder at redhat.com> wrote:
> Moreover:
> 
> * The experience of Maven users should never be penalised by uber jars. Uber jar users should be a minority compared with Maven/Gradle...etc users that have dependency engines in place to select which components they want to depend on.
> 
> Cheers,
> --
> Galder Zamarreño
> Infinispan, Red Hat
> 
> > On 7 Jun 2017, at 12:02, Galder Zamarreño <galder at redhat.com> wrote:
> >
> > As far as I see it:
> >
> > * infinispan-embedded should never be a dependency in a Maven project.
> >
> > * No uber jars should really be used as Maven dependencies because all the exclusion that fine grained dependencies allow you to do goes out of the window when all classes are inside a jar. This is not just theory, I've personally had such issues.
> >
> > * Uber jars are designed for Ant or other build tool users that don't have a dependency resolution engine in place.
> >
> > Cheers,
> >
> > p.s. I thought we had already discussed this before?
> > --
> > Galder Zamarreño
> > Infinispan, Red Hat
> >
> >> On 7 Jun 2017, at 11:50, Sebastian Laskawiec <slaskawi at redhat.com> wrote:
> >>
> >> Hey,
> >>
> >> The change was introduced by this commit [1] and relates to this JIRAs [2][3]. The root cause is in [3].
> >>
> >> Imagine a scenario where you add JCache module to your together infinispan-embedded. If your classpath was constructed in such a way that infinispan-embedded was before infinispan-core (classpath is scanned from left to right in standalone apps), we could get a relocated (uber jars move some classes into other packages) logger. That caused class mismatch errors. It is worth to mention that it will happen to all relocated classes, logger was just an example. And we need to relocate them, since a user might want to use his own, newer version of DMR or any other library. So there's no perfect solution here.
> >>
> >> Now a lot of time passed since then and we changed quite a few things. So this topic probably needs to be revisited.
> >>
> >> So the first question that we should ask, shall we allow putting jcache and infinispan-embedded together on the classpath. If the answer is yes, I believe it should stay as it is (since the user always have a choice whether he wants to use jcache with or without uber jar). The same question needs to be asked for Spring modules as well as all cache stores. The behavior needs to be consistent across all those modules.
> >>
> >> If the answer is no (which is also valid because jcache is already present in embedded uber jar), we should migrate all JBoss Logging references to Infinispan Common Logging (as Tristan did here [4]) and we can make infinispan-core as a compile time dependency to jcache. Even though migrating to Infinispan logger is not necessary, this way we won't break users app which used infinispan-embedded + jcache approach. Of course the same applies to Spring and Cache stores modules.
> >>
> >> I think the latter approach deserves some exploration. I would vote for moving that way.
> >>
> >> Thanks,
> >> Sebastian
> >>
> >> [1] https://github.com/infinispan/infinispan/commit/720f158cce38d86b292e1ce77b75509342007739
> >> [2] https://issues.jboss.org/browse/ISPN-6295
> >> [3] https://issues.jboss.org/browse/ISPN-6132
> >> [4] https://github.com/infinispan/infinispan/pull/4140/files
> >>
> >>
> >> On Wed, Jun 7, 2017 at 11:19 AM Galder Zamarreño <galder at redhat.com> wrote:
> >> Hi all,
> >>
> >> Re: https://github.com/spring-projects/spring-boot/pull/9417#discussion_r120375579
> >>
> >> Stéphane makes a good point there, why did we make core provided dependency? It does feel a bit of a pain that anyone that depends on jcache embedded also needs to depend on core.
> >>
> >> Any more details behind this decision?
> >>
> >> Cheers,
> >> --
> >> Galder Zamarreño
> >> Infinispan, Red Hat
> >>
> >> --
> >> SEBASTIAN ŁASKAWIEC
> >> INFINISPAN DEVELOPER
> >> Red Hat EMEA
> >>
> >
> 
> -- 
> SEBASTIAN ŁASKAWIEC
> INFINISPAN DEVELOPER
> Red Hat EMEA
>