Remove core feature

[vadixidav]

The core feature in Cargo.toml should be removed. If you try to build without it then the build fails:

error[E0432]: unresolved import `crate::util`
   --> .../src/lib.rs:140:16
    |
140 | pub use crate::util::{get_size, HasAfEnum, ImplicitPromote};
    |                ^^^^ maybe a missing `extern crate util;`?

Unless this is just a bug (which would need to be fixed anyways), I would recommend removing this feature. All features of a cargo package should be additive and compatible with each other without breaking the build.

[9prady9]

I am not sure I understand your concern. I added these features to enable compiling sections/modules of code without having to change entire code base when repo-wide changes are being implemented.

Also, as the name suggests core is mandatory feature that is needed to build any other feature. That is the idea.

Why do you think it needs to be removed?

[9prady9]

Ah, so if it is not included in any feature, it would be considered mandatory for any other feature being compiled? Is that what you mean?

[vadixidav]

Perhaps. I mean that core should just be included always and should not have a feature. The reason I say this is because if you omit all features then the crate does not build. If I cannot remove the core module then it shouldn't be an option. It should just always be on.

[9prady9]

I will look into what can be done. Core is useful in certain Dev situations like the one I explained earlier. I will check cargo docs if we can retain but it but make that feature mandatory

[vadixidav]

@9prady9 Basically my suggestion is to remove the core feature and all cfg statements for it in the code. Those pieces of code are necessary for arrayfire to build, therefore it is not useful as a feature since it cannot be turned on or off. Since it can't be turned on or off, it isn't a feature, but rather something required for arrayfire, thus it should not be possible to turn off by disabling the feature. It is expected that crates build even when all features are disabled.

[9prady9]

I understood your point. May I see the the cargo command that lead you to the error? Is it with --no-default-features

[vadixidav]

Actually, it is downstream:

[dependencies.arrayfire]
git = "https://github.com/arrayfire/arrayfire-rust.git"
rev = "5c5013583d0c518860d2a313204ff80dcaeba8ec"
default-features = false

[9prady9]

That's fine, just wanted to how did it happen. So you are using cargo equivalent of command line option for no default feature set.

[9prady9]

Interesting, where are specifying the required features then? In the command line?

[vadixidav]

I am specifying them in my Cargo.toml. I have to include the core feature for it to build:

[dependencies.arrayfire]
git = "https://github.com/arrayfire/arrayfire-rust.git"
rev = "5c5013583d0c518860d2a313204ff80dcaeba8ec"
default-features = false
features = ["core"]

Naturally, I will be adding more features to the features list, but I thought it was weird that arrayfire failed to compile with all the features off, and it took me a while to figure out why. It is definitely unexpected and the error is not helpful in determining the cause.

[vadixidav]

I can submit a PR to remove the feature if you are okay with the removal.

[9prady9]

I was just wondering if there is way to specify mandatory feature in cargo. Sure send the PR. You just need to edit couple of lines in src/lib.rs.

I am still not sure what should happen when we compile empty crate in rust which is essentially what you were doing earlier.