PyPy uses utf-8 internally and it’s completely hidden from the user. That’s however possible because in Python there was always a UCS2/USC4 leak to the user cod

PyPy uses utf-8 internally and it’s completely hidden from the user. That’s however possible because in Python there was always a UCS2/USC4 leak to the user code so you could never really rely on anything. I expect other languages to make the switch sooner or later. I do think though that this is not all that interesting for the issue here. WASI needs to pick some format and picking UTF-8 is fine. Roundtripping half broken UTF-16 is something that does not need preserving. I think enforcing UTF-8 there won’t be much of an issue in practice.