[bug]: Donot use assert! in NationalNumber::new function

[12089897411]

https://github.com/whisperfish/rust-phonenumber/blob/210d8df2116d34a224d97edcf3687c08e03437c8/src/national_number.rs#L28C6-L28C55

assert! cannot be used, please consider the following situation: Phone::validate_str("0xd2dc00a30027c9d5"), this process will cause the program to crash.

[rubdos]

We do not have a struct Phone nor a function validate_str that accepts random hexadecimal numbers. We should probably, however, document the panicking behaviour, and clarify that national numbers larger than 56 bits do not exist to our knowledge.

[12089897411]

Normally we deal with external untrusted characters. But the validate_str procedure can return Result<T,E> instead of crashing the program.

[rubdos]

NationalNumber::new is not supposed to take untrusted data, and it certainly does not accept characters. The PhoneNumber::from_str implementation might parse into a number of more than 56 bits and feed it to NationalNumber::new. It might be interesting to find an actual case for that.

[realtimetodie]

This code is horrible and unsafe. People should not use this library.

[rubdos]

This issue needs more context or an example crash, or any other evidence to be actionable. I'm closing this for now.

[rubdos]

@12089897411 I started playing with proptests soon after I closed this issue, and the panic actually showed up in a code path. I've patched this as per your suggestion, bubbling up the error. Thanks for reporting.