I asked on the ncurses maintainers email list about their logic and was pointed to tty_settings.c which checks:

1. stderr
2. stdout
3. stdin
4. open('/dev/tty', 'r+')

I don't know a cross-platform way to check #4 but I think #1-3 are a reasonable change to shutil.get_terminal_size().

The current logic checks only stdout. I'd like to amend that to try stderr, stdout, and stdin after checking the COLUMNS and LINES env vars. So the new logic would be:

1. Check COLUMNS and LINES env vars (for overrides)
2. Check os.get_terminal_size(stderr)
3. Check os.get_terminal_size(stdout)
4. Check os.get_terminal_size(stdin)