Sorry, AREPL has ran into an error - probably macOS

Describe the bug

Sorry, AREPL has ran into an error

Traceback (most recent call last):
  File "/usr/local/Cellar/python@3.9/3.9.2_4/Frameworks/Python.framework/Versions/3.9/lib/python3.9/asyncio/selector_events.py", line 261, in _add_reader
    key = self._selector.get_key(fd)
  File "/usr/local/Cellar/python@3.9/3.9.2_4/Frameworks/Python.framework/Versions/3.9/lib/python3.9/selectors.py", line 193, in get_key
    raise KeyError("{!r} is not registered".format(fileobj)) from None
KeyError: '5 is not registered'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/jb/.vscode/extensions/almenon.arepl-2.0.2/node_modules/arepl-backend/python/arepl_python_evaluator.py", line 298, in main
    return_info = exec_input(execArgs)
  File "/Users/jb/.vscode/extensions/almenon.arepl-2.0.2/node_modules/arepl-backend/python/arepl_python_evaluator.py", line 234, in exec_input
    asyncio.set_event_loop(asyncio.new_event_loop())
  File "/usr/local/Cellar/python@3.9/3.9.2_4/Frameworks/Python.framework/Versions/3.9/lib/python3.9/asyncio/events.py", line 761, in new_event_loop
    return get_event_loop_policy().new_event_loop()
  File "/usr/local/Cellar/python@3.9/3.9.2_4/Frameworks/Python.framework/Versions/3.9/lib/python3.9/asyncio/events.py", line 659, in new_event_loop
    return self._loop_factory()
  File "/usr/local/Cellar/python@3.9/3.9.2_4/Frameworks/Python.framework/Versions/3.9/lib/python3.9/asyncio/unix_events.py", line 54, in __init__
    super().__init__(selector)
  File "/usr/local/Cellar/python@3.9/3.9.2_4/Frameworks/Python.framework/Versions/3.9/lib/python3.9/asyncio/selector_events.py", line 61, in __init__
    self._make_self_pipe()
  File "/usr/local/Cellar/python@3.9/3.9.2_4/Frameworks/Python.framework/Versions/3.9/lib/python3.9/asyncio/selector_events.py", line 112, in _make_self_pipe
    self._add_reader(self._ssock.fileno(), self._read_from_self)
  File "/usr/local/Cellar/python@3.9/3.9.2_4/Frameworks/Python.framework/Versions/3.9/lib/python3.9/asyncio/selector_events.py", line 263, in _add_reader
    self._selector.register(fd, selectors.EVENT_READ,
  File "/usr/local/Cellar/python@3.9/3.9.2_4/Frameworks/Python.framework/Versions/3.9/lib/python3.9/selectors.py", line 523, in register
    self._selector.control([kev], 0, 0)
TypeError: changelist must be an iterable of select.kevent objects

Print Output:
Exception ignored in: <function BaseEventLoop.__del__ at 0x11871de50>
Traceback (most recent call last):
  File "/usr/local/Cellar/python@3.9/3.9.2_4/Frameworks/Python.framework/Versions/3.9/lib/python3.9/asyncio/base_events.py", line 683, in __del__
    self.close()
  File "/usr/local/Cellar/python@3.9/3.9.2_4/Frameworks/Python.framework/Versions/3.9/lib/python3.9/asyncio/unix_events.py", line 60, in close
    for sig in list(self._signal_handlers):
AttributeError: '_UnixSelectorEventLoop' object has no attribute '_signal_handlers'

To Reproduce Try typing a small program. Probably triggerable by any use of macOS and AREPL when typing a variable name that does not exist yet.

Screenshots If applicable, add screenshots to help explain your problem.

Other Information (please complete the following information):

• OS: macOS Mojave
• Python Version 3.9.2_4 Homebrew

[BrandonNav]

What about

from sys import version
print(version)
import asyncio
asyncio.set_event_loop(asyncio.new_event_loop())
asyncio.set_event_loop(asyncio.new_event_loop())

?

I managed to get this working by changing https://github.com/Almenon/AREPL-backend/blob/master/python/arepl_python_evaluator.py#L234

from asyncio.set_event_loop(asyncio.new_event_loop())

to asyncio.set_event_loop(asyncio.get_event_loop())

My environment: MacOS 11.2.3 (Big Sur) Python 3.9.3

[Almenon]

Finally got access to a Mac. I can reproduce the bug on 3.9, but the bug does not occur on 3.10. I suggest either using the fix workaround above, downgrading to 3.7, or upgrading to 3.10.

The other interesting thing is that for me this only occurs in the third arepl run.