formt-pr-files.yml

name: Format PR Files

on:
  pull_request:
    paths:
      - '**/*.md'  # Trigger workflow only when .md files are modified in the PR

jobs:
  whitespace:
    runs-on: ubuntu-latest
    permissions:
      contents: write
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
        with:
          repository: ${{ github.event.pull_request.head.repo.full_name }}
          ref: ${{ github.event.pull_request.head.ref }}
          fetch-depth: 0

      - name: Remove trailing whitespaces from Markdown files
        run: |
          echo "Target branch: ${{ github.event.pull_request.base.ref }}"
          echo "Head branch: ${{ github.event.pull_request.head.ref }}"
          
          # Get the base commit between the target branch (main) and the source branch (HEAD)
          base_branch="${{ github.event.pull_request.base.ref }}"
          head_branch="${{ github.event.pull_request.head.ref }}"
          
          git fetch origin $base_branch
          git fetch origin $head_branch
          
          base_commit=$(git merge-base origin/$base_branch origin/$head_branch)
          echo "Base commit: $base_commit"
          
           # Get the changed files in the current PR
          echo "Checking changes in PR..."
          files=$(git diff --name-only $base_commit origin/$head_branch)
          echo "Changed files: $files"

          # Filter out .md files
          file=$(echo "$files" | grep '\.md$')
          echo "Filtered .md file: $file"

          if [ -n "$file" ]; then
            echo "Processing file: $file"
            # Remove trailing spaces from each line in the file
            sed -i 's/[[:space:]]*$//g' "$file"
          fi

      - name: Push changes
        uses: EndBug/add-and-commit@v9
        with:
          message: Remove trailing spaces
          default_author: github_actions