Unexpected Status Code or Return Value

Developers often write code expecting only a subset of possible return codes—like success or a few known errors—but overlook other legitimate values the system can produce. This creates a gap where an unexpected but valid return, such as a specific error code from a library update or a rare system state, bypasses the application's logic. Without comprehensive checks, the software might misinterpret the result, proceeding as if the operation succeeded when it actually failed, or vice-versa. To prevent this, implement defensive programming by explicitly handling all documented return values, not just the common ones. Treat any unhandled return as a potential failure and design fallback mechanisms or graceful degradation paths. Always consult the official documentation for functions and APIs to understand the complete spectrum of possible outputs, and write validation logic that accounts for both expected and unexpected-but-valid scenarios to maintain system stability.