check-whitespace.yml

name: check-whitespace

on:
  pull_request:
    types: [opened, synchronize]

# Avoid unnecessary builds
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

jobs:
  check-whitespace:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v4
      with:
        fetch-depth: 0

    - name: git log --check
      id: check_out
      run: |
        echo "Starting the script."
        baseSha=${{ github.event.pull_request.base.sha }}
        git log --check --pretty=format:"---% h% s" ${baseSha}.. | tee check-results.log
        problems=()
        commit=
        commitText=
        commitTextmd=
        # Use git log --check to look for whitespace errors in each commit of this PR
        log_output=$(cat check-results.log)
        echo "${log_output}"
        # Use a for loop to iterate over lines of log_output
        IFS=$'\n'
        for line in $log_output; do
          echo "Line: ${line}"
          case "${line}" in
            "--- "*)
              IFS=' ' read -r _ commit commitText <<< "$line"
              commitTextmd="[${commit}](https://github.com/${{ github.repository }}/commit/${commit}) ${commitText}"
              ;;
            "")
              ;;
            *:[1-9]*:*) # contains file and line number information - This indicates that a whitespace error was found
              file="${line%%:*}"
              afterFile="${line#*:}" # Remove the first colon and everything before it
              lineNumber="${afterFile%%:*}"  # Remove anything after and including the first remaining colon to get only the line number
              problems+=("[${commitTextmd}]")
              problems+=("[${line}](https://github.com/${{ github.repository }}/blob/${{github.event.pull_request.head.ref}}/${file}#L${lineNumber})")
              problems+=""
              ;;
          esac
        done
        if test ${#problems[*]} -gt 0; then
          echo "⚠️ Please review the Summary output for further information." >> $GITHUB_STEP_SUMMARY
          echo "### A whitespace issue was found in one or more of the commits." >> $GITHUB_STEP_SUMMARY
          echo "" >> $GITHUB_STEP_SUMMARY
          echo "Errors:" >> $GITHUB_STEP_SUMMARY
          for i in "${problems[@]}"; do
            echo "${i}" >> $GITHUB_STEP_SUMMARY
          done
          exit 1
        fi
        echo "No problems found"