Model .save() with strange behaviour and not persisting on database

[IagoCarvalho]

Hi, the problem i was facing Is kinda straightforward:

I have 3 models:

Class B(models.model): datefield.... datefield....

Class A(PolymorphicModel, Class B): ....

Class C(Class A): ....

Class C has several properties and methods but one method in particular isn't able to actually save the data when doing a simple save operation like:

def foo(self, value): self.bar += value self.save(update_fields=['bar'])

After calling the method or in my serializer's save method:

obj.bar > "bar + value"

After the response from serializer data or in the unit test (even after refresh_from_db()): obj.bar > old value

My ugly workaround: def foo(self, value): obj = self.__class__.objects.get(id=self.id) obj.bar += value obj.save(update_fields=['bar'])

This particular method works normally with this. Considerations: It wasn't an atomic block, It didn't raise any exceptions or errors, the obj existed and had a pk, it was doing a simple update.

[Asday]

Class A(PolymorphicModel, Class B):

This is incorrect. Inherit from PolymorphicModel instead of models.Model at the base - it is not a mixin.