Versioned feature to support rstar 0.9

[rmanoka]

• I agree to follow the project's code of conduct.
• I added an entry to CHANGES.md if knowledge of this change could be valuable to users.

---

Another approach to solve resolve #660 . It seems this approach is not uncommon: eg. https://docs.rs/tokio-postgres/0.7.5/tokio_postgres/#features . It does involve a bit of boiler-plate macros though :(

[michaelkirk]

This approach makes sense to me. Thanks for workshopping with us @rmanoka.

[michaelkirk]

so, if/when we eventually make a major update to geo-types, we'd presumably drop the older rstars?

[rmanoka]

Yes, we can drop old versions based on some agreeable policy; simplest would be to drop all but latest.

Another question is we adopt a uniform "use-{crate}-{version}" name for the feature or if there's going to be one without version. I think the uniform naming makes more sense, but don't have a strong opinion.

[lnicola]

I'd say uniform. I didn't add a comment about it because it would imply a breaking change in the next release, which I assume you wanted to avoid.

[rmanoka]

Makes sense. Will add some docs so we adopt a policy at the next breaking release.

[rmanoka]

Thanks for the approvals. I'll go ahead and refactor the rstar tests to work with either feature, and merge this if all tests pass.

Any thoughts on CI? I wonder if too many versions would lead to too many combinations here. Not an issue at the moment I think.

Edit: typos

[lnicola]

I'd enable all the versions, but not test the combinations.

[rmanoka]

bors try

[bors]

try

Build succeeded:

• ci result

[rmanoka]

bors r=@lnicola,@michaelkirk

[bors]

Build succeeded:

• ci result