ValueError: filedescriptor out of range in select()

[arjanvandervelde]

Hi!

We're running into an issue that seems to have been introduced by #107. Upon opening a terminal window, it sometimes gets stuck in a never-ending loop, repeating the following error:

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/asyncio/events.py", line 81, in _run
    self._context.run(self._callback, *self._args)
  File "/usr/local/lib/python3.8/site-packages/tornado/platform/asyncio.py", line 189, in _handle_events
    handler_func(fileobj, events)
  File "/usr/local/lib/python3.8/site-packages/terminado/management.py", line 209, in pty_read
    r, _, _ = select.select([fd], [], [], .1)
ValueError: filedescriptor out of range in select()
...
...

When this happens we cannot kill the terminal from jupyter and if left unchecked it generates huge amounts of logging. We are running single-user notebooks similar to #106. It seems that poll() might be a better solution here than select(). Our environment allows for 1M open files but select() can only handle 1024.

Thanks!

-- Arjan

[blink1073]

Sounds reasonable, mind opening a PR?

[arjanvandervelde]

done.