Notes

pylifecycle.c

I just noticed that in Python/pylifecycle.c the function is_valid_fd uses fcntl(fd, F_GETFD) to tell if a fd is valid in case of __wasm__. I then read the source code of fcntl in wasi... and it is FAKE -- it always succeeds for any random input of fd!

I'm not sure if I patch pylifecycle.c or not, since this code is only used in one spot to signal a fatal error, which happens later anyways. It's just a little weird/worrisome.