Don't enforce snake_case for binary names

[Majora320]

Currently, if you have a Cargo.toml like this:

[package]
name = "some_package"
version = "0.0.0"

[[bin]]
name = "somePackage"
path = "src/main.rs"

rustc will complain:

warning: crate `somePackage` should have a snake case name such as `some_package`
  |
  = note: #[warn(non_snake_case)] on by default

I understand why this is reasonable for library crates, to enforce a common naming convention for rust libraries and source code. But it doesn't make much sense to enforce this for binaries as well, as there is no real advantage to doing so (note that the crate name isn't camelCase, only the binary name is).

---

$ rustc --version
rustc 1.22.0-nightly (05f8ddc46 2017-10-07)

[mikecluck]

I've actually been digging in to this one and would be happy to take it on, if the Rust team agrees it should happen.

Right now, building a binary passes [[bin]]::name as the --crate-name argument. I've thought of two ways of tackling this.

1. Don't enforce the snake_case rule when building a binary
2. Add an optional --bin-name flag which can be used for naming the resulting binary. Defaults back to --crate-name. This would require coordination with cargo.

Personally, I prefer 2.

[jethrogb]

Policy should apply to executables and cdylib's alike.

It would also be great if you could turn off #[warn(non_snake_case)] for the crate name only. If I use #![allow(non_snake_case)] at the top-level, that disables the lint for my entire crate.

[pipehappy1]

Policy should apply to executables and cdylib's alike.

It would also be great if you could turn off #[warn(non_snake_case)] for the crate name only. If I use #![allow(non_snake_case)] at the top-level, that disables the lint for my entire crate.

Agree, is there way to disable this warning for crate name while cargo build?

[Zingam]

This would be super simple to fix yet it is still a problem.

For example on Windows it is normal to have application names with capital letters and white spaces. We shouldn't need to manually rename the build artifact, so it would be nice to have an option to set a customized artifact name for exes and dlls.

[NickLarsenNZ]

Oh man, need this right now. Kustomize plugins look for a TitleCaseFileName.

To save having to do an extra rename, I'll just live with the warnings.

[GilShoshan94]

Hi @oli-obk and @Manishearth,

You might be the relevant people to ask for guidance (or at least to redirect to other people).
This issue is very old and I didn't see any response from a Rust member.

Is it possible to avoid the non_snake_case warning for the build artifacts without using an #![allow(non_snake_case)] at the top-level, that disables the lint for the entire crate (which is really not desirable) ?

By build artifacts, I mean for crate-type = bin | cdylib | staticlib.
So for executable, static and dynamic system library.

(To me, the most important is the binary case)

[Manishearth]

The relevant code is

rust/compiler/rustc_lint/src/nonstandard_style.rs

Line 334 in b7d8c88

let crate_ident = if let Some(name) = &cx.tcx.sess.opts.crate_name {

I think it makes sense to avoid for bin. It's not as clear for the other two and I do not want to be the one to make that call. Make a PR, I guess?

[GilShoshan94]

@Manishearth,

Thank you for the pointer!
I will try to make the PR soon.

[Manishearth]

Also FWIW this is just a suggestion, I do not know what the opinion of the relevant teams (the compiler team) is. So they may see the PR and decide that it is not the right route.

If you want to ask for a proper decision I suggest asking on the compiler team's channel on Zulip.