Ignore benchmarks when using stable/beta

Question

I have a file with some benchmarks and tests and would like to test against stable, beta and nightly. However, either I don\'t use the benchmark or stable/beta complain. Is ther

Answer 1

Is there a way to hide all the benchmark parts when using stable/beta?

Yes, and you can do it automatically using a build script, so it is not necessary to specify --features when executing cargo. In the build script you can detect the version of the Rust compiler and define a feature ("nightly" for example). Then, in the source code you can group your benchmarks and enable them if the feature was defined.

Cargo.toml

[package]
build = "build.rs"

[features]
nightly = []

[build-dependencies]
rustc_version = "0.1.*"

build.rs

extern crate rustc_version;

use rustc_version::{version_meta, Channel};

fn main() {
    if version_meta().channel == Channel::Nightly {
        println!("cargo:rustc-cfg=feature=\"nightly\"");
    }
}

src/lib.rs

#![cfg_attr(all(feature = "nightly", test), feature(test))]

#[cfg(all(feature = "nightly", test))]
extern crate test;

pub fn add_two(a: i32) -> i32 {
    a + 2
}

#[cfg(test)]
mod tests {
    // tests
}

#[cfg(all(feature = "nightly", test))]
mod benchs {
    use test::Bencher;
    // benchs
}