cargo-msrv

Find and manage the minimum supported Rust version

TLDR

Find minimum supported Rust version

$ cargo msrv find

Find using linear search

$ cargo msrv find --linear

Verify current MSRV works

$ cargo msrv verify

Show declared MSRV

$ cargo msrv show

Set MSRV in Cargo.toml

$ cargo msrv set [1.56.0]

List dependency MSRVs

$ cargo msrv list

Find for specific path

$ cargo msrv --path [/path/to/project] find

cargo msrv finds and manages the Minimum Supported Rust Version (MSRV) for Rust projects. It determines the oldest Rust compiler version that can successfully build a crate by testing against available toolchains. By default it uses binary search to efficiently narrow down the compatible version range.Maintaining an accurate MSRV is important for library authors who want to support users on older Rust versions. The tool can automatically set the `rust-version` field in Cargo.toml after finding the minimum version, and verify that the declared MSRV remains valid as the codebase evolves.

PARAMETERS

--path dir

Project directory path

--linear

Use linear search instead of binary

--min version

Minimum version to consider

--max version

Maximum version to consider

--target triple

Target platform

--manifest-path path

Path to Cargo.toml

--write-msrv

Write found MSRV to Cargo.toml after find

--ignore-lockfile

Ignore the lockfile during MSRV determination

COMMANDS

find

Discover the MSRV by testing versions

verify

Check if project works with declared MSRV

show

Display MSRV from Cargo.toml

set version

Update rust-version in Cargo.toml

list

Show MSRVs of dependencies

REQUIREMENTS

Requires rustup for toolchain management.

CAVEATS

Binary search is much faster than linear for the many Rust minor versions. Requires rustup for downloading and managing toolchains. The `find` command compiles the project with each candidate version, which can be slow for large projects. The `rust-version` field in Cargo.toml only supports two-component versions (e.g., 1.56) since Rust 1.56.