From embedded programming, over smart contracts in Rust, to general cross-platform portable crates, #![no_std] crates are becoming more and more widespread.
However it is currently a very cumbersome process to find out if and why (not) a crate is compatible with no_std usage, and often requires a lengthy trial and error process, and digging through the source of all your dependencies.
cargo nono tries to aid you in navigating the current minefield that is no_std usage, and it's biggest "no no"s.
cargo-nono also comes as prebuilt binaries (useful for CI):
curl -LSfs https://japaric.github.io/trust/install.sh | \
sh -s -- --git hobofan/cargo-nonocargo install cargo-nono
# For warnings with more informative messages install like this
RUSTFLAGS="--cfg procmacro2_semver_exempt" cargo install cargo-nono
Run in the crate directory you want to check:
cargo nono check
The cargo nono check subcommand also understands the --no-default-features and --features <FEATURES> flags to help in conditional no_std setups.
- Tries to infer
no_stdcompatibility in dependencies by looking for a#![no_std]attribute or the often used conditional#![cfg_attr(not(feature = "std"), no_std)] - Helps in pinpointing which dependencies and feature flags activate
stdfeature flags - Warn of
use std::statements in code
- Warn of
[build-dependencies]features bleeding over: cargo#5730
Licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.