Inline field for None returns an object with every key set to null instead of just null

[dappiu]

Maybe not an issue and I'm just missing something. I'll try to explain me with some code

I have a situation like this:

class UserStatusResource(ModelResource):
    class Meta:
        model = UserStatus


class UserResource(ModelResource):
    class Meta:
        model = User

    class Schema:
        # id_user_status is an Integer ForeignKey referencing a single UserStatus row
        # user_status is a sqlalchemy.orm.relationship()
        # Here I want the UserStatus object embedded in the User repr, and not just a $ref
        user_status = fields.Inline('user_status')

Now, I'm expecting that when I fetch a user instance (GET /user/), if the instance has the id_user_status set to None (and consequently user_status relationship also returns None), the value of the key user_status to be None.
Instead I get an object with every field of the user-status resource set to None (exception made for the $uri that is set to /user-status/None)

I tried passing nullable=True and default=None to Inline(), but nothing changes.

Is this the correct behaviour? Is there a way in which I can change this behaviour and simply get a null value as a representation for None?

Thanks

[xD8A]

It seems to me that it's not correct behavior, cause resource bound to invalid uri. You can get a null value with that patch:

--- schema.py.old       2019-08-19 15:12:04.712622200 +0400
+++ schema.py   2019-08-19 15:07:01.547122200 +0400
@@ -213,6 +213,8 @@
         return all(((i.default is not None) or i.nullable for i in (self.fields or {}).values()))

     def format(self, item):
+        if item is None:
+            return None
         return OrderedDict((key, field.output(key, item)) for key, field in self.fields.items() if 'r' in field.io)

     def convert(self, instance, update=False, pre_resolved_properties=None, patchable=False, strict=False):