GenericRelation with a string argument will raise an AttributeError when accessed.

[martin-c]

In other relationship fields it is possible to specify the target model by passing its model name as a string, such as

class Car(models.Model):
    manufacturer = models.ForeignKey('production.Manufacturer')

However, in the case of a GenericRelation,

class Car(models.Model):
    manufacturers = GenericRelation('production.Manufacturer')

accessing the manufacturers field will cause a AttributeError to be raised.

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/Users/.../.python-env/lib/python2.7/site-packages/django/contrib/contenttypes/fields.py", line 406, in __get__
    superclass = rel_model._default_manager.__class__
AttributeError: 'unicode' object has no attribute '_default_manager'

So it seems only the target class instance can be passed to GenericRelation().

[Tim Graham]

I had no trouble using strings in a test project and there are several string references inside a GenericRelation in Django's test suite. Please reopen if you can provide a minimal project to reproduce.