name: Python CI

on:
  pull_request:
    branches:
      - main
    paths:
      - '**.py'

jobs:
  python-lint:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v3
        with:
          # This is a bit heavy handed, but we need `origin/main` to get a ref to diff against
          fetch-depth: 0

      - name: Setup Python
        uses: actions/setup-python@v3
        with:
          python-version: '3.9.x'
          cache: 'pip'
          architecture: 'x64'

      - name: Install flake8
        run: pip install flake8

      - name: Run Flake8 Lint
        run: |
          DIFF="$(git --no-pager diff -u $(git merge-base HEAD origin/main) -- '**/*.py')"
          echo "$DIFF" | flake8 --diff