Term.size() always returns size of stdout, even if target is stderr

[ian-mcdowell]

I'm trying to read the size of the terminal attached to stderr while stdout is redirected to a file.

/path/to/program > out.txt

let term = Term::buffered_stderr();
let size = term.size();

The above code is returning the default terminal size, since terminal_size is calling the isatty on STDOUT_FILENO and returning None. (see unix_term.rs:49)

This is likely a simple fix: Use the raw file descriptor from the Term when checking isatty, instead of hard coding STDOUT_FILENO.

[mitsuhiko]

As weird as it sounds this was done intentional. I think it requires some rethinking but it's not uncommon that only stdout is connected to a terminal and then the call fails for no reason. Maybe a better solution would be to check either handle? I'm not sure.