AppRegistryNotReady caused by __init__.py

[jayvdb]

The easy fix is to not import everything into __init__, but that changes the API. The bad solution is to tell people to not list the app in INSTALLED_APPS. The ugly solution is to change views.py to import DRF internals inside the methods where they are needed, not importing at the top.

python3 manage.py migrate

  ...
  File "/usr/lib/python3.8/site-packages/rest_flex_fields/__init__.py", line 3, in <module>
    from .views import FlexFieldsModelViewSet
  File "/usr/lib/python3.8/site-packages/rest_flex_fields/views.py", line 6, in <module>
    from rest_framework import viewsets
  File "/usr/lib/python3.8/site-packages/rest_framework/viewsets.py", line 27, in <module>
    from rest_framework import generics, mixins, views
  File "/usr/lib/python3.8/site-packages/rest_framework/generics.py", line 9, in <module>
    from rest_framework import mixins, views
  File "/usr/lib/python3.8/site-packages/rest_framework/views.py", line 17, in <module>
    from rest_framework.schemas import DefaultSchema
  File "/usr/lib/python3.8/site-packages/rest_framework/schemas/__init__.py", line 33, in <module>
    authentication_classes=api_settings.DEFAULT_AUTHENTICATION_CLASSES,
  File "/usr/lib/python3.8/site-packages/rest_framework/settings.py", line 220, in __getattr__
    val = perform_import(val, attr)
  File "/usr/lib/python3.8/site-packages/rest_framework/settings.py", line 168, in perform_import
    return [import_from_string(item, setting_name) for item in val]
  File "/usr/lib/python3.8/site-packages/rest_framework/settings.py", line 168, in <listcomp>
    return [import_from_string(item, setting_name) for item in val]
  File "/usr/lib/python3.8/site-packages/rest_framework/settings.py", line 177, in import_from_string
    return import_string(val)
  File "/usr/lib/python3.8/site-packages/django/utils/module_loading.py", line 17, in import_string
    module = import_module(module_path)
  File "/usr/lib64/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/usr/lib/python3.8/site-packages/rest_framework_jwt/authentication.py", line 17, in <module>
    from rest_framework_jwt.blacklist.exceptions import (
  File "/usr/lib/python3.8/site-packages/rest_framework_jwt/blacklist/exceptions.py", line 8, in <module>
    class MissingToken(AuthenticationFailed):
  File "/usr/lib/python3.8/site-packages/rest_framework_jwt/blacklist/exceptions.py", line 10, in MissingToken
    msg = _('The token is missing.')
  File "/usr/lib/python3.8/site-packages/django/utils/translation/__init__.py", line 105, in ugettext
    return gettext(message)
  File "/usr/lib/python3.8/site-packages/django/utils/translation/__init__.py", line 92, in gettext
    return _trans.gettext(message)
  File "/usr/lib/python3.8/site-packages/django/utils/translation/trans_real.py", line 354, in gettext
    _default = _default or translation(settings.LANGUAGE_CODE)
  File "/usr/lib/python3.8/site-packages/django/utils/translation/trans_real.py", line 267, in translation
    _translations[language] = DjangoTranslation(language)
  File "/usr/lib/python3.8/site-packages/django/utils/translation/trans_real.py", line 154, in __init__
    self._add_installed_apps_translations()
  File "/usr/lib/python3.8/site-packages/django/utils/translation/trans_real.py", line 195, in _add_installed_apps_translations
    raise AppRegistryNotReady(
django.core.exceptions.AppRegistryNotReady: The translation infrastructure cannot be initialized before the apps registry is ready. Check that you don't make non-lazy gettext calls at import time.

Also occurs with drf_extended_viewset and beda-software/drf-writable-nested#93