runic-action

April 22, 2026 · View on GitHub

A GitHub Action to run the Runic.jl code formatter.

Usage

Full (copy-pasteable) workflow file example:

---
name: Check
on:
  push:
    branches:
      - 'master'
      - 'release-'
    tags:
      - '*'
  pull_request:
jobs:
  runic:
    name: Runic formatting
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      # - uses: julia-actions/setup-julia@v2
      #   with:
      #     version: '1.11'
      # - uses: julia-actions/cache@v2
      - uses: fredrikekre/runic-action@v1
        with:
          version: '1'

This runs Runic's check mode, with diff output, on all Julia files in the checked out repository.

The julia-actions/setup-julia and julia-actions/cache actions are optional. Without the former runic-action will use whatever julia version is installed in the runner by default.

Important

Please be aware of Runic's version policy when configuring the version. Pinning to a major release (as above with version: '1') may cause occasional CI failures whenever there is a new minor release of Runic that happens to impact your code base. When this happens you simply have to i) re-run Runic on the new version, ii) commit the result, and iii) add the commit to the ignore list. This is still recommended since minor releases should be relatively rare, and if you use Runic you presumably want these minor bugfixes to be applied to your code base. The alternative is to pin to a minor (or patch) version and manually upgrade to new minor versions.

Posting format diff as GitHub review comments

By passing format_files: true to the action and combining with e.g. reviewdog/action-suggester a format diff will be posted as GitHub review comments. Note that in order for the job to exit with appropriate error you need to also configure continue-on-error for the runic job, and set the fail_level (or similar for any other follow up action you are using) as in the example below.

---
name: Check
on:
  push:
    branches:
      - 'master'
      - 'release-'
    tags:
      - '*'
  pull_request:
jobs:
  runic:
    name: Runic formatting
    runs-on: ubuntu-latest
    # Permissions needed for reviewdog/action-suggester to post comments
    permissions:
      contents: read
      checks: write
      issues: write
      pull-requests: write
    steps:
      - uses: actions/checkout@v4
      # - uses: julia-actions/setup-julia@v2
      #   with:
      #     version: '1.11'
      # - uses: julia-actions/cache@v2
      - uses: fredrikekre/runic-action@v1
        with:
          version: '1'
          format_files: true
        # Fail on next step instead
        continue-on-error: ${{ github.event_name == 'pull_request' }}
      - uses: reviewdog/action-suggester@v1
        if: github.event_name == 'pull_request'
        with:
          tool_name: Runic
          fail_level: warning

Inputs

runic-action accepts the following inputs:

- uses: fredrikekre/runic-action@v1
  with:
    # Runic.jl version number or git revision (commit, tag, branch).
    # Please see the note above about Runic's version policy.
    # By default runic-action@v1 uses the latest release in the v1 release series.
    version: '1'
    # Comma-separated list of file extensions to format.
    # Requires Runic >= 1.7 for markdown support.
    extensions: 'jl'
    # When `true`, format Julia code blocks in docstrings.
    # Requires Runic >= 1.7.
    docstrings: false
    # When `true`, format the files and leave the repository dirty (in addition to running
    # the usual check). Note that the exit code of the step is still the exit code of check.
    format_files: false