fix(build): split path types in compile

[aquarhead]

Same idea as tokio-rs/prost#496 (it should explain both motivation and solution)

[davidpdrsn]

Could this be a breaking change?

[aquarhead]

Yes, I believe it will break if includes was empty, like &[]. The workaround I used in prost is change to &[""], but I'd like to know if there's a better solution.

[davidpdrsn]

Ah right yeah. Can't think of a way around that 🤔 std::env::join_paths has the same issue, although that does allow you to use turbofish. I see thats also how you wrote it initially here.

I personally not sure using impl AsRef<Path> is strictly better than regular generic bounds but I suppose an empty includes is quite a niche use-case, though I'm not sure. Never done it myself 🤷

[aquarhead]

The problem is that both protos and includes are using the same generic parameter, so they need to be of same type to make the compiler happy, which can be unnecessary and manual type conversion code.

I guess a solution is to provide another compile_simple function that does not take includes? Or just document this case?

[davidpdrsn]

Or just document this case?

I would be okay with that I think. @LucioFranco what do you think?

[LucioFranco]

Yes, this is a breaking change so lets hold off on it until we go for 0.6. We can keep the PR open though since it will still work down the line.