Patched code sample

def decode_with_try_except(data: bytes, encoding: str = "unicode_escape", errors: str = "ignore") -> str:
    """
    Safely decodes bytes using a try-except block to handle potential DecodeErrors.
    Replaces the error handler approach with try-except block
    This avoids the CVE-2025-4516 issue, if it occurs when using the "unicode_escape" encoding
    """
    try:
        return data.decode(encoding)
    except UnicodeDecodeError:
        # Handle the decoding error as needed. In this example, it is replaced or ignored
        if errors == "replace":
            return data.decode(encoding, errors="replace")  # Decode, replacing invalid chars.
        elif errors == "ignore":
            return data.decode(encoding, errors="ignore") # Decode, ignoring invalid chars.
        else:
            # Re-raise the exception if errors is not 'replace' or 'ignore'.  This matches
            # standard decode behavior if an error occurs and error handling is not available.
            raise

# Example usage:
if __name__ == '__main__':
    # Potential vulnerable example
    data = b'abc\\ud800def'  # Invalid unicode sequence
    
    # Fixed version using try-except:
    decoded_string = decode_with_try_except(data, "unicode_escape", errors="ignore") # or "replace"
    print(f"Decoded string (ignore): {decoded_string}")

    decoded_string = decode_with_try_except(data, "unicode_escape", errors="replace")
    print(f"Decoded string (replace): {decoded_string}")

    # Demonstrate the default case that re-raises the error:
    try:
        decoded_string = decode_with_try_except(data, "unicode_escape", errors="strict") # errors="strict" or any other value except "ignore" and "replace" re-raises the exception
        print(f"Decoded string (strict): {decoded_string}")
    except UnicodeDecodeError as e:
        print(f"Caught expected UnicodeDecodeError: {e}")