Should WString use memcpy not strcpy

[petejan]

In WString.cpp (this also applies to avr core)

https://github.com/arduino/ArduinoCore-samd/blob/master/cores/arduino/WString.cpp#L179 and
https://github.com/arduino/ArduinoCore-samd/blob/master/cores/arduino/WString.cpp#L271

strcpy is used, where are length is passed to the copy and concat operation, whereas memcpy should be used so the char* can contain the 0 character.

[Reneg973]

Well AFAIK we talk about null terminated strings? So why should a null in this case not terminate it?
Of course there are sometimes strings, which are split by a "\0" and finalized by a "\0\0". In this case String is not the correct object to handle it.

[matthijskooijman]

Usually, strings will be NUL-terminated, but the String class already stores an explicit length and supports passing a length to some methods and constructors, which means it should be able to support strings with embedded NUL characters too. Note that the String class is now developed as part of the ArdunoCore-API repo, so this issue should probably be discussed there. Some changes wrt to supporting strings with NUL have been made already in arduino/ArduinoCore-API#97, and some remaining issues are tracked in https://github.com/arduino/ArduinoCore-API/issue/111 https://github.com/arduino/ArduinoCore-API/issue/112 (though those are probably not all issues, maybe a container "support strings with embedded NUL" issue would make sense).

Maybe this issue could be closed in favor of the existing (or a new) issues in the -API repo?