#32103: runserver: NotImplementedError (with Python 3.8 on Windows)
-------------------------------------+-------------------------------------
Reporter: Andrey | Owner: nobody
Zelenchuk |
Type: Bug | Status: new
Component: Core | Version: 3.1
(Management commands) |
Severity: Release | Keywords:
blocker |
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
The `runserver` management command does not work with Python ≥ 3.8 on
Windows.
=== Steps to reproduce
1. Open any Django project.
2. Run `python manage.py runserver`.
==== Actual result
{{{
C:\Programs\Python38\python.exe C:/project/manage.py runserver
2020-10-11 18:12:08,823 INFO [django.utils.autoreload] Watching for file
changes with StatReloader
Exception in thread django-main-thread:
Traceback (most recent call last):
File "C:\Programs\Python38\lib\threading.py", line 932, in
_bootstrap_inner
self.run()
File "C:\Programs\Python38\lib\threading.py", line 870, in run
self._target(*self._args, **self._kwargs)
File "C:\Programs\Python38\lib\site-
packages\django\utils\autoreload.py", line 53, in wrapper
fn(*args, **kwargs)
File "C:\Programs\Python38\lib\site-
packages\django\core\management\commands\runserver.py", line 110, in
inner_run
autoreload.raise_last_exception()
File "C:\Programs\Python38\lib\site-
packages\django\utils\autoreload.py", line 76, in raise_last_exception
raise _exception[1]
File "C:\Programs\Python38\lib\site-
packages\django\core\management\__init__.py", line 357, in execute
autoreload.check_errors(django.setup)()
File "C:\Programs\Python38\lib\site-
packages\django\utils\autoreload.py", line 53, in wrapper
fn(*args, **kwargs)
File "C:\Programs\Python38\lib\site-packages\django\__init__.py", line
24, in setup
apps.populate(settings.INSTALLED_APPS)
File "C:\Programs\Python38\lib\site-packages\django\apps\registry.py",
line 91, in populate
app_config = AppConfig.create(entry)
File "C:\Programs\Python38\lib\site-packages\django\apps\config.py",
line 116, in create
mod = import_module(mod_path)
File "C:\Programs\Python38\lib\importlib\__init__.py", line 127, in
import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
File "<frozen importlib._bootstrap>", line 991, in _find_and_load
File "<frozen importlib._bootstrap>", line 975, in
_find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 783, in exec_module
File "<frozen importlib._bootstrap>", line 219, in
_call_with_frames_removed
File "C:\Programs\Python38\lib\site-packages\channels\apps.py", line 6,
in <module>
import daphne.server
File "C:\Programs\Python38\lib\site-packages\daphne\server.py", line 20,
in <module>
asyncioreactor.install(twisted_loop)
File "C:\Programs\Python38\lib\site-
packages\twisted\internet\asyncioreactor.py", line 320, in install
reactor = AsyncioSelectorReactor(eventloop)
File "C:\Programs\Python38\lib\site-
packages\twisted\internet\asyncioreactor.py", line 69, in __init__
super().__init__()
File "C:\Programs\Python38\lib\site-packages\twisted\internet\base.py",
line 571, in __init__
self.installWaker()
File "C:\Programs\Python38\lib\site-
packages\twisted\internet\posixbase.py", line 286, in installWaker
self.addReader(self.waker)
File "C:\Programs\Python38\lib\site-
packages\twisted\internet\asyncioreactor.py", line 151, in addReader
self._asyncioEventloop.add_reader(fd, callWithLogger, reader,
File "C:\Programs\Python38\lib\asyncio\events.py", line 501, in
add_reader
raise NotImplementedError
NotImplementedError
}}}
==== Expected result
No errors.
=== Workaround
Add the following code to the `manage.py` file:
{{{
#!python
if sys.platform == 'win32' and sys.version_info >= (3, 8):
import asyncio
asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
}}}
=== References
- https://stackoverflow.com/questions/58908293/i-keep-getting-
notimplementederror-error-when-starting-django-server
--
Ticket URL: <https://code.djangoproject.com/ticket/32103>
Django <https://code.djangoproject.com/>
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