rs-fmt-check Action

Rustfmt suggestions in your Pull Requests

This GitHub Action executes rustfmt and posts all suggestions as annotations for the pushed commit ².

This GitHub Action is based on clechasseur/rs-clippy-check, which itself has been forked from actions-rs/clippy-check. See LICENSE for copyright attribution details.

Example workflow

Note: this workflow uses actions-rust-lang/setup-rust-toolchain to install the most recent nightly rustfmt ¹.

name: Rustfmt check

on: push

jobs:
  rustfmt_check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
      - uses: actions-rust-lang/setup-rust-toolchain@6044e13b5dc448c55e2357c09f80417699197238 # v6.2.0
        with:
          toolchain: nightly
          components: rustfmt
      - uses: clechasseur/rs-fmt-check@v4.0.5

Inputs

All inputs are optional.

Name	Description	Type	Default
toolchain	Rust toolchain to use 1	string	nightly
args	Arguments for the cargo fmt command	string
working-directory	Directory where to perform the cargo fmt command	string

For extra details about the toolchain and args inputs, see rs-cargo Action.

Release immutability

Starting with release 4.0.0, this GitHub action's releases will be marked as immutable. This means that once a release is created, its tag cannot be modified in any way.

Previously, best practices for using GitHub actions in workflows were to pin the actions to a specific Git commit hash. With immutable releases, this is no longer necessary and the actual Git tag is safe to use. Because of this, starting with release 4.0.0, this GitHub action will no longer provide a floating major version tag (like v4, for example). To use a specific version of this action, pin it to the release tag (like v4.0.0).

Notes

¹ : This action currently relies on an unstable rustfmt feature (emit json) and as such, requires a nightly toolchain at the minimum. You should not change the value of the toolchain parameter unless you know the specified toolchain supports the feature correctly.

² : Currently, GitHub sets a limit of 10 warning annotations per run (see this page for more information). So if there are more than 10 suggestions returned by rustfmt, only the first 10 will appear as PR annotations. The other suggestions will still appear in the check run summary (see this one for example).