Support declaring versions inside module-info

[PaintNinja]

Currently the dependency versions need to be in the version catalogue or buildscript. It would be nice if they could be parsed from comments inside the module-info, similar to how runtimeOnly deps are handled. For example:

module example {
    requires org.slf4j; // version 2.0.7
}

[jjohannes]

This is an interesting idea for "single module" projects. (For a multi-module project – i.e. a build with subprojects – you usually want to define the versions separately.)

I think it should be possible to add such a feature. We need to agree on a syntax. I wonder if the proposed // version 2.0.7 is too verbose and if just // 2.0.7 would be enough 🤔. For "parsing" the comment, a keyword like version would probably be good though. Or just some special character like :2.0.7 as : what you use in build files before a version. Wdyt?

Would you be interested in contributing this feature? We would need to parse the comment associated with a directive here and then store that information in addition to the module name. And retrieve it when constructing a dependency here.

[PaintNinja]

I suggested // version 2.0.7 as it fits well with existing module keywords, like exports foo to bar. Not a fan of the : prefix as it implies Maven artifact coordinates, which module names don't always match up with and thus may cause confusion... it also looks close to ; which could be a footgun.

Thanks for the hints on how to implement this, unfortunately I'm pretty mediocre at Gradle plugin development currently and busy working on other things so unable to file a PR at this time.