name: "Checking EditorConfig"

permissions: read-all

on:
  # avoids approving first time contributors
  pull_request_target:
    branches-ignore:
      - 'release-**'

jobs:
  tests:
    runs-on: ubuntu-latest
    if: github.repository_owner == 'NixOS'
    steps:
    - uses: actions/checkout@v2
    - uses: cachix/install-nix-action@v16
      with:
        # nixpkgs commit is pinned so that it doesn't break
        nix_path: nixpkgs=https://github.com/NixOS/nixpkgs/archive/f93ecc4f6bc60414d8b73dbdf615ceb6a2c604df.tar.gz
    - name: install editorconfig-checker
      run: nix-env -iA editorconfig-checker -f '<nixpkgs>'
    - name: Get list of changed files from PR
      run: |
        git fetch origin --depth 1 ${{ github.event.pull_request.head.sha }}
        git checkout ${{ github.event.pull_request.head.sha }}

        git fetch origin --depth 1 ${{ github.event.pull_request.base.sha }}
        git checkout ${{ github.event.pull_request.base.sha }}

        git fetch origin --depth 1 pull/${{ github.event.pull_request.number }}/merge
        # check this out last as editorconfig should check this commit
        git checkout FETCH_HEAD

        # everything except --diff-filter=D (deleted)
        git diff --diff-filter=ACMRTUXB --name-only ${{ github.event.pull_request.base.sha }} ${{ github.event.pull_request.head.sha }} > $HOME/changed_files
    - name: Checking EditorConfig
      run: |
        cat $HOME/changed_files | xargs -r editorconfig-checker -disable-indent-size
    - if: ${{ failure() }}
      run: |
        echo "::error :: Hey! It looks like your changes don't follow our editorconfig settings. Read https://editorconfig.org/#download to configure your editor so you never see this error again."