Multiple inheritance bug on deletion (Django 1.10)

[icpetcu]

I have the following structure:

A (PolymorphicModel)
/ |
| D -- E
B -- C

When I try to delete all A instances with A.objects.all().delete(), I get the following error:

AttributeError: 'E' object has no attribute 'b_ptr'

I've tested the same scenario without polymorphic and it works fine.

[jberends]

I have the same problem for Django 1.11.

We've implemented a BPMN class structure with multiple inheritance

end_event -> throw_event -> event -> flownode -> flowelement -> baseelement(BaseModel, Polymorphic)

it works in django 1.9

[jberends]

seems to be the same bug in #229.

Fixed it the following way

class BaseElement(Model, PolymorphicModel):
    class Meta:
        base_manager_name = 'base_objects'

[TiphaineLAURENT]

I have the same problem using Django 3.1