This is a GitHub Action to automatically format source code in pull requests using dotnet format.

First add an .editorconfig file describing the desired code style of the repository (unless you want the default code style in .NET).

Once the .editorconfig file is in place, the next step is to fix all the code style issues in the repository. If you're only fixing formatting issues, the following command can fix the entire repository (when executed from the root of the repository):

dotnet format whitespace --folder .

If you're fixing style issues as well, you need to pass either a solution or a project that contains the source code to format:

dotnet format tabseverywhere.sln

The last step is to add the GitHub actions as described below, and then any pull requests that propose changes that violate the coding style as specified in the .editorconfig file, will automatically get fixed (and the fix pushed to the pull request).

Note that if the fixes should automatically be applied to the pull request, then use the rolfbjarne/autoformat-push action as well.

Add a new file named autoformat.yml in the .github/workflows directory in your repository.

This is a minimal sample:

name: Autoformat code
on: pull_request

# This action only need a single permission in order to autoformat the code.
permissions:
  contents: read

jobs:
  autoformat-code:
    name: Autoformat code
    runs-on: ubuntu-latest

    steps:
    - name: 'Autoformat'
      uses: rolfbjarne/[email protected]
      with:
        projects: myproject.csproj

There are three ways of specifying what to format:

1. Passing a value for script. This is the path to a shell script that will be executed and should format the source code as desired (technically it can modify any files in the repository for any reason).
2. Passing a space-separated list of projects for projects. The action will call dotnet format <project> on each project (only if script isn't set).
3. The default is to run dotnet format whitespace --folder <root directory> (if neither script nor project is set). This will format the entire repository.

If the repository contains any modified files after the dotnet format command (or the script) has executed, the action will create a patch with those changes.

The patch will be zipped up, and uploaded as an artifact.

If the patch should be automatically applied to the pull request, then use the rolfbjarne/autoformat-push action.

The full list of configuration options:

uses: rolfbjarne/[email protected]
  with:
    # A script to execute that will run 'dotnet format' (or any other logic that changes any committed files)
    # If neither 'script' nor 'projects' is specified, the action will run 'dotnet format whitespace' on the entire repository.
    script: ''

    # Space-delimited list of projects or solutions (relative to the root of the repository) to format.
    # This option has no effect if 'script' is specified.
    # If neither 'script' nor 'projects' is specified, the action will run 'dotnet format whitespace' on the entire repository.
    projects: ''

    # The committer's email for the patch
    git_user_email: '[email protected]'

    # The committer's name for the patch
    git_user_name: 'GitHub Actions Autoformatter'
  
    # The commit message to use for the patch
    git_commit_message: 'Auto-format source code'

    # The name of the artifact where the patch is stored
    artifact: 'autoformat'

    # Only consider autoformatting for files modified in the pull request.
    onlyFilesModifiedInPullRequest: false

    # The .NET executable to use to run 'dotnet format ...'
    dotnetExecutable: 'dotnet'

    # The working directory to use when running 'dotnet format ...'.
    # This does not apply when using a custom script.
    workingDirectory: '..'