csharp-version-check-fallback.yml

name: C# 7.3 Check (Fallback)

on:
  pull_request:
    paths:
      - "**.cs"
  push:
    branches:
      - main
    paths:
      - "**.cs"

jobs:
  # This job acts as a fallback when self-hosted runner is offline
  # It will only run if the primary workflow fails to start within the timeout
  csharp-version-check-fallback:
    name: Verify C# 7.3 Compatibility (GitHub Runner)
    runs-on: ubuntu-latest
    permissions:
      contents: read

    steps:
      - name: Checkout repository
        uses: actions/checkout@v7

      - name: Scan for C# 8.0+ Features
        shell: bash
        run: |
          echo "🔍 Running C# 7.3 compatibility check on GitHub-hosted runner..."
          echo "ℹ️  This is a fallback in case self-hosted runner is unavailable"
          echo ""

          violations=0

          # Null-coalescing assignment (??=)
          if grep -rnF '??=' --include='*.cs' .; then
            echo "❌ Found null-coalescing assignment (??=) - C# 8.0+"
            violations=$((violations + 1))
          fi

          # Switch expressions
          if grep -rEn 'switch.*=>.*}' --include='*.cs' .; then
            echo "❌ Found switch expressions - C# 8.0+"
            violations=$((violations + 1))
          fi

          # Index from end operator
          if grep -rn '\[\^' --include='*.cs' .; then
            echo "❌ Found index from end operator ([^) - C# 8.0+"
            violations=$((violations + 1))
          fi

          # Range operator
          # Match [start..end] pattern roughly
          if grep -rEn '\[.*[0-9a-zA-Z_]\.\.[0-9a-zA-Z_].*\]' --include='*.cs' .; then
            echo "❌ Found range operator ([..]) - C# 8.0+"
            violations=$((violations + 1))
          fi

          # Nullable pragmas
          if grep -rn '#nullable' --include='*.cs' .; then
            echo "❌ Found #nullable pragma - C# 8.0+"
            violations=$((violations + 1))
          fi

          # Using declarations (using var)
          if grep -rEn 'using[[:space:]]+var[[:space:]]+' --include='*.cs' .; then
            echo "❌ Found using declarations (using var) - C# 8.0+"
            violations=$((violations + 1))
          fi

          if [ $violations -gt 0 ]; then
            echo ""
            echo "::error::Found $violations C# 8.0+ feature(s). Please use C# 7.3 compatible syntax."
            echo "See CONTRIBUTING.md for C# 7.3 constraints and alternatives."
            exit 1
          fi

          echo "✅ No C# 8.0+ features detected - code is C# 7.3 compatible"