pylint_on_pull_request.yml

name: PyLint On Pull Request
on: [pull_request]
jobs:
  build:
    runs-on: ubuntu-20.04
    steps:
    - name: Set Up Python
      uses: actions/setup-python@v2
    - name: Install PyLint
      run: pip install --upgrade pylint
    - name: Checkout
      uses: actions/checkout@v2
      with:
        fetch-depth: 0
    - name: Checkout Head
      run: git checkout $HEAD_REF
      env:
        HEAD_REF: ${{ github.event.pull_request.head.ref }}
    - name: Checkout Base
      run: git checkout $BASE_REF
      env:
        BASE_REF: ${{ github.event.pull_request.base.ref }}
    - name: Get Base Lint Score
      run: |
        echo BASE_LINT=$(git diff --name-only --diff-filter=M $HEAD_REF | grep -E "\.py" | xargs pylint | grep -E -o "at [0-9.-]+" | grep -E -o [0-9.-]+) >> $GITHUB_ENV
      env:
        HEAD_REF: ${{ github.event.pull_request.head.ref }}
      if: always()
    - name: Set Base Lint to 0
      run: echo BASE_LINT=0 >> $GITHUB_ENV
      if: env.BASE_LINT == ''
    - name: Checkout Head
      run: git checkout $HEAD_REF
      env:
        HEAD_REF: ${{ github.event.pull_request.head.ref }}
    - name: Get Head Lint Score
      run: |
        echo HEAD_LINT=$(git diff --name-only --diff-filter=M $BASE_REF | grep -E "\.py" | xargs pylint | grep -E -o "at [0-9.-]+" | grep -E -o [0-9.-]+) >> $GITHUB_ENV
      env:
        BASE_REF: ${{ github.event.pull_request.base.ref }}
      if: always()
    - name: Set Head Lint to 0
      run: echo HEAD_LINT=0 >> $GITHUB_ENV
      if: env.HEAD_LINT == ''
    - name: Get Added Files Lint Score
      run: |
        echo ADDED_LINT=$(git diff --name-only --diff-filter=A $BASE_REF | grep -E "\.py" | xargs pylint | grep -E -o "at [0-9.-]+" | grep -E -o [0-9.-]+) >> $GITHUB_ENV
      env:
        BASE_REF: ${{ github.event.pull_request.base.ref }}
      if: always()
    - name: Get Delta
      run: |
        import os
        base = float(os.environ['BASE_LINT'])
        head = float(os.environ['HEAD_LINT'])
        delta = head - base
        os.popen(f"echo DELTA={round(delta, 2)} >> $GITHUB_ENV")
      shell: python
    - name: Display Results
      run: |
        echo "Lint of modified files in base:"
        echo ${{ env.BASE_LINT }}
        echo "Lint of modified files in head:"
        echo ${{ env.HEAD_LINT }}
        echo "Delta (+/-):"
        echo ${{ env.DELTA }}
        echo "Lint of files added by head:"
        echo ${{ env.ADDED_LINT }}
      if: always()
    - name: Fail If Negative Delta
      run: |
        import os
        if float(os.environ['HEAD_LINT']) < 9 and float(os.environ['DELTA']) < 0:
            raise Exception("Head lint score < 9 and negative delta.")
      shell: python