Zernit/.github/workflows/shell.yml

name: Shell

# Relevant to events - https://help.github.com/en/actions/automating-your-workflow-with-github-actions/events-that-trigger-workflows
on: 
  pull_request:
    types: [synchronize, opened, reopened, ready_for_review]
    paths:
    - '**.sh'

jobs:
  # Linting
  lint:
    runs-on: ubuntu-latest
    container: debian:stable
    steps:
      - name: Installing dependencies..
        run: |
          # Sync repos
          # Check for git
          if ! apt list --installed 2>/dev/null | grep -qP "^git\/stable.*"; then
            # Check if we can install git
            if ! apt list | grep -qP "^git\/stable.*"; then
              apt update
            elif apt list | grep -qP "^git\/stable.*"; then
              true
            else
              exit 255
            fi
            # Install git
            apt install -y git
          elif apt list --installed 2>/dev/null | grep -qP "^git\/stable.*"; then
            true
          else
            exit 255
          fi 
          # Check for shellcheck
          if ! apt list --installed 2>/dev/null | grep -qP "^shellcheck\s{1}-.*"; then
            # Check if we can install shellcheck
            if ! apt list | grep -qP "^shellcheck\s{1}-.*"; then
              apt update
            elif apt list | grep -qP "^shellcheck\s{1}-.*"; then
              true
            else
              exit 255
            fi
            # Install shellcheck
            apt install -y shellcheck
          elif apt list --installed 2>/dev/null | grep -qP "^shellcheck\s{1}-.*"; then
            true
          else
            exit 255
          fi           
      - name: Pulling git dir..
        uses: actions/checkout@v2
      - name: Processing files..
        # Make sure that bash is used
        shell: bash
        run: |
          cd "$GITHUB_WORKSPACE"

          # Process files
          ## NOTICE: Do not use for loop to avoid pitfall https://mywiki.wooledge.org/BashPitfalls#pf1
          git --git-dir="$GITHUB_WORKSPACE/.git" ls-files -z -- '*.sh' | while IFS= read -rd '' file; do
              printf 'linting shell file %s\n' "$file"
              shellcheck --external-sources --shell=sh "$file"
          done