Incorrectly identify queryset as not iterable when model manager is a subclass

[SpoonMeiser]

Since upgrading to version 0.8.0 (and pylint 1.8) we're incorrectly getting an error that a queryset is not iterable:

E: 49,29: Non-iterable value MyModel.objects.filter(foo=bar) is used in an iterating context (not-an-iterable)

MyModel in this case is a subclass of a model that has objects set to a subclass of of the usual manager (in particular, it uses model_utils.managers.InheritanceManager)

Similar uses where the standard manager is used does not cause this error, and we did not get this error with previous versions of pylint and pylint-django.

[antdking]

suspect it's not picking up the class properly if you use the shortcut.

As a workaround, I've changed my managers to be defined like so:

from django.db.models import manager


class MyModelManager(manager.Manager):
    ...

will want to revert this change once the regression is fixed.

[SpoonMeiser]

model_utils is a third party module, not written by us, so we can't really change it.

FWIW, the manager is defined like this:

class InheritanceManager(InheritanceManagerMixin, models.Manager):
    pass

https://github.com/jazzband/django-model-utils/blob/master/model_utils/managers.py#L262

[atodorov]

@SpoonMeiser can you post a reproducer which includes all the necessary imports and empty class definitions (e.g. using pass) so I can try and reproduce.

@cybojenix I think you are right but without the full reproducer I can't really do anything.

[SpoonMeiser]

Ok, with python 2.7

$ pip install pylint pylint-django django==1.10 django-model-utils

Test file:

from django.db import models
from model_utils.managers import InheritanceManager


class BaseModel(models.Model):
    objects = InheritanceManager()

    field = models.CharField()


class SubModel(BaseModel):
    pass


def function():
    for r in SubModel.objects.filter(field='foo'):
        print r.field

Linting with pylint-django:

$ pylint -E --load-plugins=pylint_django test.py
Using config file /home/oj/.pylintrc
************* Module test
E: 16,13: Non-iterable value SubModel.objects.filter(field='foo') is used in an iterating context (not-an-iterable)
Traceback (most recent call last):
  File "/home/oj/virtualenv/pd-repoducer/bin/pylint", line 11, in <module>
    sys.exit(run_pylint())
  File "/home/oj/virtualenv/pd-repoducer/local/lib/python2.7/site-packages/pylint/__init__.py", line 16, in run_pylint
    Run(sys.argv[1:])
  File "/home/oj/virtualenv/pd-repoducer/local/lib/python2.7/site-packages/pylint/lint.py", line 1347, in __init__
    linter.check(args)
  File "/home/oj/virtualenv/pd-repoducer/local/lib/python2.7/site-packages/pylint/lint.py", line 768, in check
    self._do_check(files_or_modules)
  File "/home/oj/virtualenv/pd-repoducer/local/lib/python2.7/site-packages/pylint/lint.py", line 901, in _do_check
    self.check_astroid_module(ast_node, walker, rawcheckers, tokencheckers)
  File "/home/oj/virtualenv/pd-repoducer/local/lib/python2.7/site-packages/pylint/lint.py", line 980, in check_astroid_module
    walker.walk(ast_node)
  File "/home/oj/virtualenv/pd-repoducer/local/lib/python2.7/site-packages/pylint/utils.py", line 1016, in walk
    cb(astroid)
  File "/home/oj/virtualenv/pd-repoducer/local/lib/python2.7/site-packages/pylint_django/augmentations/__init__.py", line 671, in wrap_func
    with_method(orig_method, *args, **kwargs)
  File "/home/oj/virtualenv/pd-repoducer/local/lib/python2.7/site-packages/pylint_django/augmentations/__init__.py", line 290, in ignore_import_warnings_for_related_fields
    iterat = to_consume[0].items if PY3 else to_consume[0].iteritems
TypeError: 'NamesConsumer' object does not support indexing

The traceback I'd not seen before.

[antdking]

We've been getting this error since updating to pylint 1.8.2. Suggest replicating with 1.8.1 until the above error is resolved.

[atodorov]

The NamesConsumer error is #120 and was fixed in version 0.9.0

[SpoonMeiser]

Why is this labelled as an enhancement? Surely it's a bug/regression?

[hermansc]

I'm also seeing this issue..

qs = Model.objects.filter(...)
for item in qs:
    pass

[stsewd]

In Read the Docs something similar to what @hermansc described happened (with pylint=1.8.3 and pylint-django==0.9.4). The problem was with astroid==1.6.2, using astroid==1.6.1 solves the problem.

[rmecham]

I still run into this issue with pylint==1.8.3, pylint-django==0.9.4, and astroid==1.6.1. (I've also tried astroid==1.6.0 and astroid==1.6.2.)

[nirsalon]

as far as i see, the issue isn't resolved. see this:

from model_utils.managers import InheritanceManager

class Unit(models.Model):
    sim = models.CharField(max_length=64, null=True, blank=True)
    objects = InheritanceManager()

installed_units = Unit.objects.filter(sim__isnull=False)
ids = [u.sim for u in installed_units]

[E1133(not-an-iterable), ] Non-iterable value installed_units is used in an iterating context

using pylint==1.8.4 and pylint-django==0.11

[atodorov]

@nirsalon this is a new issue but related. file it separately.

[timothyshaw]

FWIW, I was getting not-an-iterable and unsubscriptable-object when using a custom manager, until I used what @cybojenix suggested previously. Changing:

from django.db import models
CustomManager(models.Manager):
    ...

to:

from django.db.models import manager
CustomManager(manager.Manager):
    ...

Did the trick. I am currently using pylint==1.8.2 and pylint-django==0.11.