Mark maven plugin goals @threadSafe

[jfallows]

Fix #95.

I have reviewed the code for each moditect plugin goal and it seems as though they use project relative resources only, triggering no conflicts when running in a multi-threaded parallel build.

[aalmiray]

What does it mean for a plugin to be marked as threadsafe? The docs don't say much, do they?

AFAICT the add-module-info goal modifies the project's artifact by rewriting it. If another goal works on the same artifact at the same time, then there's no guarantee on the outcome, is there? Similarly, the generate-module-info goal could find itself in a similar position.

I don't think we can mark all ModiTect mojos as threadsafe.

[gunnarmorling]

AFAICT the add-module-info goal modifies the project's artifact by rewriting it. If another goal works on the same artifact at the same time, then there's no guarantee on the outcome, is there?

Can this actually happen? IIUC, parallelism in Maven refers to building multiple modules concurrently, but not execute the goals of one module concurrently. I.e. if a plug-in can run safely for different modules at the same time, it should be fine. There's some context here.

[aalmiray]

Gotcha. If parallelism is executed per module as a whole, instead of per goals within a module then I think we're good to go and mark all mojos as threadsafe.

[gunnarmorling]

Yeah, at least I am not aware of any way for running the goals of one module in parallel.

[gunnarmorling]

Merged. Thx, @jfallows!