// HIGH QUALITY: Strict numeric validation with reasonable defaults if ($num === false || $num === null) // Not a valid integer http_response_code(400); die(json_encode(['error' => 'Quantity (num) must be a valid integer']));
// If product already in cart, update quantity (add to existing) if (isset($_SESSION['cart'][$product_id])) $new_quantity = $_SESSION['cart'][$product_id]['quantity'] + $num; addcartphp num high quality
// Assuming $pdo is your database connection $stmt = $pdo->prepare("SELECT id, name, price, stock_quantity FROM products WHERE id = ? AND status = 'active'"); $stmt->execute([$product_id]); $product = $stmt->fetch(PDO::FETCH_ASSOC); if (!$product) die(json_encode(['error' => 'Product not found'])); // HIGH QUALITY: Strict numeric validation with reasonable
// Validate product exists and has sufficient stock // ... proceed // If product already in cart
$_POST['num'] = '5'; $_POST['product_id'] = '101'; $this->expectOutputRegex('/"success":true/'); include 'add_to_cart.php';