Django 2.0.13 -> 2.1 upgrade causes std library function to not find module (AttributeError)

Question

Upgrading Django 2.0.13 -> 2.1.0 (or greater) causes the following error when calling runserver, migrate etc.

On Django 2.0.13 (and any lower) does not throw this error.

Traceback (most recent call last):
  File "/usr/lib/python3.6/logging/config.py", line 390, in resolve
     found = getattr(found, frag)
AttributeError: module 'mysite' has no attribute 'mymodule'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/usr/lib/python3.6/logging/config.py", line 565, in configure
    handler = self.configure_handler(handlers[name])
File "/usr/lib/python3.6/logging/config.py", line 715, in configure_handler
    klass = self.resolve(cname)
File "/usr/lib/python3.6/logging/config.py", line 393, in resolve
    found = getattr(found, frag)
AttributeError: module 'mysite' has no attribute 'mymodule'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/home/me/mysite/manage.py", line 20, in <module>
    execute_from_command_line(sys.argv)
File "/home/me/venv/lib/python3.6/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
File "/home/me/venv/lib/python3.6/site-packages/django/core/management/__init__.py", line 357, in execute
    django.setup()
File "/home/me/venv/lib/python3.6/site-packages/django/__init__.py", line 19, in setup
    configure_logging(settings.LOGGING_CONFIG, settings.LOGGING)
File "/home/me/venv/lib/python3.6/site-packages/django/utils/log.py", line 76, in configure_logging
    logging_config_func(logging_settings)
File "/usr/lib/python3.6/logging/config.py", line 802, in dictConfig
    dictConfigClass(config).configure()
File "/usr/lib/python3.6/logging/config.py", line 573, in configure
    '%r: %s' % (name, e))
ValueError: Unable to configure handler 'console': module 'mysite' has no attribute 'mymodule'

This error is thrown in class BaseConfigurator(object):

The same issue is also with python3.8

Tracing the error to settings.py -> LOGGING

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'verbose': {
            'format': '%(levelname)s %(asctime)s %(module)s %(process)d %(thread)d %(message)s',
        },
        'simple': {
            'format': '%(levelname)s %(message)s',
        },
    },
    'filters': {
        'require_debug_false': {
            '()': 'django.utils.log.RequireDebugFalse'
        },
    },
    'handlers': {
        'console': {
            'level': 'DEBUG',
            'class': 'mysite.mymodule.log.TheConsoleHandler',
            'formatter': 'simple',
        },
        ...
    },
    'loggers': {
        ...
    },
}

If I comment this out all the handlers (and loggers) this error won't be thrown.

Looking at https://docs.djangoproject.com/en/3.0/releases/2.1/ I have hard time understanding what change is causing this or how to debug it.

Project structure (related items)

mysite/
  __init__.py #called twice after upgrade to 2.1
  manage.py
  settings.py
  urls.py
  wsgi.py
  local_settings.py
  mymodule/ #this module is not found from mysite
     __init__.py #empty
     log.py 
     ...
  othermodule/ #moving log.py to this or any other module just causes fail there
  ...

One important note is that for whatever reason, after upgrade to 2.1 mysite/__init__.py is called twice! (--noreload flag is applied). Not sure if this is related to the problem though.

mysite/__init__.py

from uwsgi_tasks import set_uwsgi_callbacks, django_setup

set_uwsgi_callbacks()
django_setup()

mysite/manage.py

import os
import sys

if __name__ == "__main__":
    package_dir = os.path.dirname(os.path.abspath(__file__))
    sys.path.remove(package_dir)
    sys.path.insert(0, os.path.normpath(os.path.join(package_dir, '..')))
    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "mysite.settings")
    from django.core.management import execute_from_command_line

    execute_from_command_line(sys.argv)

mysite/mymodule/log.py (content reduced which is irrelevant)

# encoding=utf-8
import logging
import sys


class TheConsoleHandler(logging.Handler):

    def __init__(self):
        logging.Handler.__init__(self)

    def emit(self, record):
        # irrelevant if has content or not, error is thrown anyway
        pass

Answer 1

The code in mysite/__init__.py needs to be moved to mysite/manage.py.

Credits to Alasdair for helping me debug.