Generate META-INF/services from module-info.java

[mtdowling]

Based on the discussion in #84, I'm convinced that library authors that create modular JARs should define their service providers in both module-info.java and in META-INF/services to ensure that their JARs work on the classpath.

Given how important it is to make JARs work on the classpath and how poorly supported in general JPMS is today (excluding this library!), I think it would be very useful for this library to have the option to generate META-INF/services files for each service provider detected in a module-info.java. If the library detects that META-INF/services already exist or that any of the service providers use the static provides method, then it would fail the build.

[big-andy-coates]

Sounds like a great option. Happy to accept a PR.

[SiboVG]

Hey @big-andy-coates I'd like to work on this, but I have 0 experience with this repo's codebase. Could you recommend how and where I should implement this feature?

[big-andy-coates]

Hi @SiboVG - it would be great if you could. I don't have that much familiarity with the code base I'm afraid. I've taken over maintenance of the repo to keep it alive.

I would suggest that this feature should be implemented as its own Gradle task, and will probably need to be disabled by default for backwards compatibility. Maybe with an extension option to enable it. Please also ensure the main docs are updated to cover the new functionality and suitable tests are added.

I'm happy to help review and guide as you go.