#23726: Unhelpful Python 3 error message when loading app with misconfigured
manager
-------------------------------+--------------------
Reporter: inglesp | Owner: nobody
Type: Bug | Status: new
Component: Uncategorized | Version: 1.7
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------+--------------------
I had a model whose `objects` class attribute was a subclass of
`models.Manager`, and not an instance of a subclass of `models.Manager`.
That is, I had the following:
{{{
class Track(models.Model):
...
objects = TrackManager
...
}}}
With Python 2.7, when `django.setup()` gets called, I get a helpful error
message:
{{{
$ python2.7 manage.py shell
Traceback (most recent call last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/Users/peteringlesby/.virtualenvs/django_katas/lib/python2.7/site-
packages/django/core/management/__init__.py", line 385, in
execute_from_command_line
utility.execute()
File "/Users/peteringlesby/.virtualenvs/django_katas/lib/python2.7/site-
packages/django/core/management/__init__.py", line 354, in execute
django.setup()
File "/Users/peteringlesby/.virtualenvs/django_katas/lib/python2.7/site-
packages/django/__init__.py", line 21, in setup
apps.populate(settings.INSTALLED_APPS)
File "/Users/peteringlesby/.virtualenvs/django_katas/lib/python2.7/site-
packages/django/apps/registry.py", line 108, in populate
app_config.import_models(all_models)
File "/Users/peteringlesby/.virtualenvs/django_katas/lib/python2.7/site-
packages/django/apps/config.py", line 202, in import_models
self.models_module = import_module(models_module_name)
File
"/usr/local/Cellar/python/2.7.6/Frameworks/Python.framework/Versions/2.7/lib/python2.7/importlib/__init__.py",
line 37, in import_module
__import__(name)
File "/Users/peteringlesby/projects/django_katas/katas/models.py", line
26, in <module>
class Track(models.Model):
File "/Users/peteringlesby/.virtualenvs/django_katas/lib/python2.7/site-
packages/django/db/models/base.py", line 170, in __new__
new_class.add_to_class(obj_name, obj)
File "/Users/peteringlesby/.virtualenvs/django_katas/lib/python2.7/site-
packages/django/db/models/base.py", line 299, in add_to_class
value.contribute_to_class(cls, name)
TypeError: Error when calling the metaclass bases
unbound method contribute_to_class() must be called with TrackManager
instance as first argument (got ModelBase instance instead)
}}}
With Python 3.4, I don't:
{{{
$ python3.4 manage.py shell
Traceback (most recent call last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/usr/local/lib/python3.4/site-
packages/django/core/management/__init__.py", line 385, in
execute_from_command_line
utility.execute()
File "/usr/local/lib/python3.4/site-
packages/django/core/management/__init__.py", line 354, in execute
django.setup()
File "/usr/local/lib/python3.4/site-packages/django/__init__.py", line
21, in setup
apps.populate(settings.INSTALLED_APPS)
File "/usr/local/lib/python3.4/site-packages/django/apps/registry.py",
line 108, in populate
app_config.import_models(all_models)
File "/usr/local/lib/python3.4/site-packages/django/apps/config.py",
line 202, in import_models
self.models_module = import_module(models_module_name)
File
"/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/importlib/__init__.py",
line 109, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 2254, in _gcd_import
File "<frozen importlib._bootstrap>", line 2237, in _find_and_load
File "<frozen importlib._bootstrap>", line 2226, in
_find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 1200, in _load_unlocked
File "<frozen importlib._bootstrap>", line 1129, in _exec
File "<frozen importlib._bootstrap>", line 1471, in exec_module
File "<frozen importlib._bootstrap>", line 321, in
_call_with_frames_removed
File "/Users/peteringlesby/projects/django_katas/katas/models.py", line
26, in <module>
class Track(models.Model):
File "/usr/local/lib/python3.4/site-packages/django/db/models/base.py",
line 170, in __new__
new_class.add_to_class(obj_name, obj)
File "/usr/local/lib/python3.4/site-packages/django/db/models/base.py",
line 299, in add_to_class
value.contribute_to_class(cls, name)
TypeError: contribute_to_class() missing 1 required positional argument:
'name'
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/23726>
Django <https://code.djangoproject.com/>
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