Allow nullable foreign keys

[idan-david]

In the case of a model with a nullable foreign key to another model the from_django method does not currently work.

I've added a check for Optional types in the dict method, which extracts the correct type

class A(models.Model):
    value = models.CharField(max_length=256, null=True, blank=True)


class B(models.Model):
    a = models.ForeignKey(A, null=True, blank=True, on_delete=models.CASCADE)

[jonathan-s]

Looks like UnionType doesn't exist in python 3.8 and 3.9 either.

[idan-david]

You are correct. After some reading, UnionType was introduced in 3.10, with the "|" annotation (e.g. int | str).
I can make the tests compatible for python 3.8 by removing this syntax, but still supporting this check (with an import only if sys.version_info >= (3,10)).
This means I can support this syntax, but not check for it in a test.
What do you suggest we do?

[jonathan-s]

@idan-david This looks ok to me. The import on line 6 needs to be removed though. Let's see if the tests pass after this.

[idan-david]

Sorry for the mess, removed the import on line 6

[idan-david]

This was causing problems with python 3.9, added the inspect.isclass(arg)

[jonathan-s]

@idan-david 🎉 thanks for taking the time

[idan-david]

Thank you for your patience