Platform detection on macOS: 'win' in 'darwin' in sys.platform

[Xiang Zhang]

In utilities.py, line 288:

if 'win' in sys.platform:  # True on macOS where sys.platform=='darwin'
    ...
    ...
    log(' detected Windows platform')...  # wrong behavior

On macOS where sys.platform='darwin', 'win' in sys.platform returns True, so pexpect.popen_spawn.PopenSpawn` instead of pexpect.spawn is used to open processes, which may be bad.

In my personal experience (macOS 12.4, amp-atomistics 1.0, pexpect 4.8.0), Python throws TIMEOUT: <pexpect.popen_spawn.PopenSpawn` after the log file logs Starting local connections. But if I manually substitute the line with if 'win' in sys.platform and 'darwin' not in sys.platform, the computation proceeds normally.

[andrew_peterson]

Thanks for reporting. Maybe we should be detecting with platform.system() instead of sys.platform? See this link. I only have linux so am not sure how to check.

Better than checking platforms might be to do a try ... except loop? If it’s due to a simple change in import location, we could do something like:

try:
    from pexpect import spawn  # posix platforms
except ImportError:
    from pexpect.popen_spawn import PopenSpawn as spawn  # Windows

Of course, the above doesn’t work if both commands exist in both places. (Both import lines do work on linux.)

Perhaps a windows user can chime in? Those lines of code were written by @ericmusa, who could perhaps suggest if the above will work.