trailing-whitespace-check.yml

name: Whitespace Check

on:
  workflow_call:

jobs:
  check-whitespace:
    runs-on: ubuntu-latest
    permissions:
      contents: read

    steps:
    - name: Checkout code
      uses: actions/checkout@v4
      with:
        fetch-depth: 0

    - name: Check for trailing whitespace
      run: |
        echo "Checking for trailing whitespace in changed files..."

        # Get the base branch
        BASE_SHA="${{ github.event.pull_request.base.sha }}"
        HEAD_SHA="${{ github.event.pull_request.head.sha }}"

        # Get list of changed files (excluding deleted files)
        CHANGED_FILES=$(git diff --name-only --diff-filter=d "$BASE_SHA" "$HEAD_SHA")

        if [ -z "$CHANGED_FILES" ]; then
          echo "No files to check."
          exit 0
        fi

        # File patterns to check (text files)
        PATTERNS="\.cs$|\.csproj$|\.sln$|\.ts$|\.html$|\.css$|\.scss$"

        # Directories and file patterns to exclude
        EXCLUDE_PATTERNS="(^|\/)(\.|node_modules|bin|obj|artifacts|packages|\.vs|\.nuke\/temp)($|\/)"

        ERRORS_FOUND=0
        TEMP_FILE=$(mktemp)

        while IFS= read -r file; do
          # Skip if file doesn't exist (shouldn't happen with --diff-filter=d, but just in case)
          if [ ! -f "$file" ]; then
            continue
          fi

          # Check if file matches patterns to check
          if ! echo "$file" | grep -qE "$PATTERNS"; then
            continue
          fi

          # Check if file should be excluded
          if echo "$file" | grep -qE "$EXCLUDE_PATTERNS"; then
            continue
          fi

          # Find trailing whitespace lines, excluding XML doc placeholder lines that are exactly "/// " (one space)
          MATCHES=$(grep -n '[[:space:]]$' "$file" | grep -vE '^[0-9]+:[[:space:]]*/// $' || true)

          if [ -n "$MATCHES" ]; then
            echo "❌ Trailing whitespace found in: $file"
            echo "$MATCHES" | head -10
            TOTAL=$(echo "$MATCHES" | wc -l)
            if [ "$TOTAL" -gt 10 ]; then
              echo "   ... and $(($TOTAL - 10)) more lines"
            fi
            echo "1" >> "$TEMP_FILE"
          fi
        done <<< "$CHANGED_FILES"

        ERRORS_FOUND=$(wc -l < "$TEMP_FILE" 2>/dev/null || echo "0")
        rm -f "$TEMP_FILE"

        if [ "$ERRORS_FOUND" -gt 0 ]; then
          echo ""
          echo "❌ Found trailing whitespace in $ERRORS_FOUND file(s)."
          echo "Please remove trailing whitespace from the files listed above."
          exit 1
        else
          echo "✅ No trailing whitespace found in changed files."
          exit 0
        fi