[duckerude]

The big problem isn't invalid UTF-8 but invalid UTF-16 (on Windows et al). AIUI Go had nasty bugs around this (https://github.com/golang/go/issues/59971) until it recently adopted WTF-8, an encoding that was actually invented for Rust's OsStr.

WTF-8 has some inconvenient properties. Concatenating two strings requires special handling. Rust's opaque types can patch over this but I bet Go's WTF-8 handling exposes some unintuitive behavior.

There is a desire to add a normal string API to OsStr but the details aren't settled. For example: should it be possible to split an OsStr on an OsStr needle? This can be implemented but it'd require switching to OMG-WTF-8 (https://rust-lang.github.io/rfcs/2295-os-str-pattern.html), an encoding with even more special cases. (I've thrown my own hat into this ring with OsStr::slice_encoded_bytes().)

The current state is pretty sad yeah. If you're OK with losing portability you can use the OsStrExt extension traits.

[klodolph]

Yeah, I avoided talking about Windows which isn’t UTF-16 but “int16 string” the same way Unix filenames are int8 strings.

IMO the differences with Windows are such that I’m much more unhappy with WTF-8. There’s a lot that sucks about C++ but at least I can do something like

  #if _WIN32
  using pathchar = wchar_t;
  constexpr pathchar sep = L'\\';
  #else
  using pathchar = char;
  constexpr pathchar sep = '/';
  #endif
  using pathstring = std::basic_string<pathchar>;

Mind you this sucks for a lot of reasons, one big reason being that you’re directly exposed to the differences between path representations on different operating systems. Despite all the ways that this (above) sucks, I still generally prefer it over the approaches of Go or Rust.