Multiple QuarkusApplicationClassBuildItem

[CodeSimcoe]

Description

Hello,

It is currently not possible to produce multiple QuarkusApplicationClassBuildItem.
That rather makes sense.

But from my understanding it is based on a declarative basis, not an effective one.

Example :
I have 2 extensions that declare a production of such an item, but do not effectively produce it.
Still, build is in error.

Code example
https://github.com/CodeSimcoe/quarkus-main-clash

Real world need :
I am trying to use both picocli and a custom QuarkusApplication (for JavaFX needs).
Even if picocli does not effectively produce its QuarkusApplicationClassBuildItem if a @QuarkusMain is found within the application, the build is in error, as shown in my example.

[ERROR] Failed to execute goal io.quarkus.platform:quarkus-maven-plugin:3.7.1:build (default) on project code-with-quarkus: Failed to build quarkus application: io.quarkus.builder.Ch
ainBuildException: Multiple producers of item class io.quarkus.deployment.builditem.QuarkusApplicationClassBuildItem (io.quarkus.my.ext.a.deployment.MyExtAProcessor#mainProducer): Th
is is the location of the conflicting producer (io.quarkus.my.ext.b.deployment.MyExtBProcessor#mainProducer)

I don't know if making QuarkusApplicationClassBuildItem a MultiBuildItem makes any sense, but maybe if there is no effective production like in my example, it shall build.

Thanks

Implementation ideas

No response