id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
32197	Misleading error when loading a database backend fails with ImportError	Tim Graham	Hasan Ramezani	"For example, in the following case, `django_cockroachdb` is installed but has an import error itself.
{{{
Traceback (most recent call last):
  File ""/home/tim/code/django/django/db/utils.py"", line 110, in load_backend
    return import_module('%s.base' % backend_name)
  File ""/home/tim/.virtualenvs/django39/lib/python3.9/importlib/__init__.py"", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File ""<frozen importlib._bootstrap>"", line 1030, in _gcd_import
  File ""<frozen importlib._bootstrap>"", line 1007, in _find_and_load
  File ""<frozen importlib._bootstrap>"", line 972, in _find_and_load_unlocked
  File ""<frozen importlib._bootstrap>"", line 228, in _call_with_frames_removed
  File ""<frozen importlib._bootstrap>"", line 1030, in _gcd_import
  File ""<frozen importlib._bootstrap>"", line 1007, in _find_and_load
  File ""<frozen importlib._bootstrap>"", line 986, in _find_and_load_unlocked
  File ""<frozen importlib._bootstrap>"", line 680, in _load_unlocked
  File ""<frozen importlib._bootstrap_external>"", line 790, in exec_module
  File ""<frozen importlib._bootstrap>"", line 228, in _call_with_frames_removed
  File ""/home/tim/code/cockroach-django/django_cockroachdb/__init__.py"", line 2, in <module>
    from .lookups import patch_lookups
  File ""/home/tim/code/cockroach-django/django_cockroachdb/lookups.py"", line 1, in <module>
    from django.db.models.fields.json import HasKeyLookup, KeyTransform
ModuleNotFoundError: No module named 'django.db.models.fields.json'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File ""/home/tim/code/mysite/manage.py"", line 10, in <module>
    execute_from_command_line(sys.argv)
  File ""/home/tim/code/django/django/core/management/__init__.py"", line 381, in execute_from_command_line
    utility.execute()
  File ""/home/tim/code/django/django/core/management/__init__.py"", line 357, in execute
    django.setup()
  File ""/home/tim/code/django/django/__init__.py"", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File ""/home/tim/code/django/django/apps/registry.py"", line 114, in populate
    app_config.import_models()
  File ""/home/tim/code/django/django/apps/config.py"", line 211, in import_models
    self.models_module = import_module(models_module_name)
  File ""/home/tim/.virtualenvs/django39/lib/python3.9/importlib/__init__.py"", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File ""<frozen importlib._bootstrap>"", line 1030, in _gcd_import
  File ""<frozen importlib._bootstrap>"", line 1007, in _find_and_load
  File ""<frozen importlib._bootstrap>"", line 986, in _find_and_load_unlocked
  File ""<frozen importlib._bootstrap>"", line 680, in _load_unlocked
  File ""<frozen importlib._bootstrap_external>"", line 790, in exec_module
  File ""<frozen importlib._bootstrap>"", line 228, in _call_with_frames_removed
  File ""/home/tim/code/mysite/polls/models.py"", line 12, in <module>
    class Question(models.Model):
  File ""/home/tim/code/django/django/db/models/base.py"", line 117, in __new__
    new_class.add_to_class('_meta', Options(meta, app_label))
  File ""/home/tim/code/django/django/db/models/base.py"", line 321, in add_to_class
    value.contribute_to_class(cls, name)
  File ""/home/tim/code/django/django/db/models/options.py"", line 204, in contribute_to_class
    self.db_table = truncate_name(self.db_table, connection.ops.max_name_length())
  File ""/home/tim/code/django/django/db/__init__.py"", line 28, in __getattr__
    return getattr(connections[DEFAULT_DB_ALIAS], item)
  File ""/home/tim/code/django/django/db/utils.py"", line 201, in __getitem__
    backend = load_backend(db['ENGINE'])
  File ""/home/tim/code/django/django/db/utils.py"", line 121, in load_backend
    raise ImproperlyConfigured(
django.core.exceptions.ImproperlyConfigured: 'django_cockroachdb' isn't an available database backend.
Try using 'django.db.backends.XXX', where XXX is one of:
    'mysql', 'oracle', 'postgresql', 'sqlite3'
}}}
I'm not sure there's anything that could be done besides rephrasing the error message to say something like this:

 'django_cockroachdb' isn't an available database backend or couldn't be imported. Check the above exception.

In this case, ""Try using..."" isn't so helpful either. Perhaps we could only include that if `backend_name` begins with `django.`."	Cleanup/optimization	closed	Database layer (models, ORM)	dev	Normal	fixed			Ready for checkin	1	0	0	0	1	0