[Build] Fix core-modules profile on JDK11

[lhotari]

Motivation

"core-modules" profile is broken on JDK11. core-modules profile allows building a subset of the modules. It is used in the unit test builds.
The current Pulsar build is designed in a way that main profile shouldn't be active when core-modules or docker profile is active.

Modifications

• Fix the usages of core-modules and docker profiles so that the main profile is explicitly de-activated from the command line by passing -main (same as !main, but doesn't require quotes in a unix shell) to the list of profiles for -P on the maven command line.

  • For example:
    • -Pcore-modules,-main to activate core-modules
    • -Pdocker,-main to activate the docker profile.

• make the "always activate" solution for main profile more explicit and add comments in pom.xml about it

[lhotari]

@eolivelli Please review. This PR revisits the modifications in pom.xml added as part of #9893.

[eolivelli]

good catch

[merlimat]

@lhotari A couple of things are not 100% clear to me:

1. If it's activeByDefault, shouldn't the profile be always active?
2. If we need to activate it explicitly, that would mean that a simple mvn install won't work anymore?

[lhotari]

@lhotari A couple of things are not 100% clear to me:

1. If it's activeByDefault, shouldn't the profile be always active?

Maven's activeByDefault is not very intuitive. It doesn't activate a profile if there's already some other profile activate based on a rule. (one of many Stackoverflow questions about this).
Since the jdk11 profile gets activated based on the jdk version, that prevents main profile from activating.

2. If we need to activate it explicitly, that would mean that a simple mvn install won't work anymore?

It seems that explicit activation is needed in a form or another to enable a solution for a build that has different configuration for JDK11. I've been trying to find a solution to that problem without finding a good solution. It seems that it would be possible to write a custom org.apache.maven.model.profile.ProfileSelector implementation to handle the situation. However, I'd rather find an out-of-the-box solution if that would be available.
This maven extension looks useful: https://github.com/sviperll/ozymandias/tree/master/maven-profiledep-extension . I also found https://github.com/random-maven/profile-activator-extension , which could solve the problem.

It is really annoying if mvn install stops working. I'll revisit this PR once more to fix that. However, I don't have a solution yet.

[lhotari]

The current Pulsar build is designed in a way that main profile shouldn't be active when core-modules or docker profile is active.

I have now pushed a solution where I ended up fixing the usages of core-modules and docker profiles so that the main profile is explicitly de-activated from the command line by passing -main/!main to the list of profiles for -P on the maven command line.

For example:

• -Pcore-modules,-main to activate core-modules
• -Pdocker,-main to activate the docker profile.

@eolivelli @merlimat PTAL