Developing with Cargo outside the ChromeOS chroot

Sometimes when developing Rust code (e.g when using an IDE) it can be convenient to be able to run cargo from outside the chroot.

To facilitate this we wrap cargo, rustc and rustfmt. The rust-toolchain.toml file in project root directory causes the tools to be invoked via scripts/chroot-shim which uses bwrap to emulate the chroot configuration and translate paths of the results.

By wrapping the tools we avoid having to maintain complete duplicate Rust configurations inside and outside the chroot.

Setting up Outside the chroot

1. Install rustup by following the instructions at rustup.rs.
2. Install bwrap: sudo apt install bubblewrap