macOS builds failing with "unexpected `cfg` condition value: `cargo-clippy`"

[micahrj]

This is happening due to an issue in the objc crate: SSheldon/rust-objc#125

I think that ideally Baseview would just switch to the objc2 crate, but that would require a decent amount of work since it's not a drop-in replacement. The simpler workaround for now would probably be to point at the master branch of the rust-objc repo, since a fix for the issue has been merged but was never published to crates.io.

[micahrj]

I gave this a try and ran into the issue that the cocoa crate also depends on the objc crate, so the workaround would require forking cocoa as well.

[paravozz]

@micahrj
I dug into this earlier, tested a small build.rs workaround that silences the warning locally:

fn main() {
  println!("cargo:rustc-check-cfg=cfg(feature, values(\"cargo-clippy\"))");
}

Happy to help with either, or with the objc2 migration.

UPD: just in case, to speed things up, filed a PR with that fix: #231.

UPD2: Filed #232 with the objc2 macros-only migration; supersedes #231. Kept cocoa for framework type bindings to leave the bigger cocoa-replacement decision open, since you flagged that direction. PR also folds in fixes for several latent @encode and NSException traps the stricter objc2 verification surfaces.

[micahrj]

It looks like we already had #![allow(unexpected_cfgs)] attributes in the relevant modules, but for some reason they have stopped working:

1. baseview/src/macos/mod.rs

   Line 3 in 237d323

   #![allow(unexpected_cfgs)]

2. baseview/src/gl/macos.rs

   Line 3 in 237d323

   #![allow(unexpected_cfgs)]

I've found that if I move the attribute to the crate root it successfully silences the warning again: #233