Model.refresh_from_db() no longer refreshes related objects

[Thomas Berdy]

After updating to Django 2.1 from Django 2.0.7, I noticed one of my tests failed. After further investigation, I figured out the problem was coming from refresh_from_db method. Here is my test:

    s = MyCustomSerializer()
    order = s.create(copy.deepcopy(order_data))

    # Check shipping_address exists
    assert order.shipping_address

    order_data["shipping_address"]["city"] = "Sevran"
    s.update(order, copy.deepcopy(order_data))
    order.refresh_from_db()

    # Check order's shipping_address has been updated
    assert order.shipping_address.city == "Sevran"

Here you can find the definition (light version) of the Order model:

class Order(TimeStampedModel):
    shipping_address = models.ForeignKey(
        "order.ShippingAddress", null=True, blank=True,
        verbose_name=_("Shipping Address"), on_delete=models.SET_NULL
    )

Before 2.1, refresh_from_db refresh the whole object and the objects linked by foreign key.
Now it seems that only the first-level object is refreshed.
Is it normal ? Maybe you can mention it in the release notes.

[Tim Graham]

Can you simplify your steps to reproduce with some minimal models and without MyCustomSerializer and the deepcopy stuff? It's difficult to tell exactly what's happening in your code. Ideally, you could also ​bisect to find the commit where the behavior changed. 136bf5c2142ae3261669d02e2dd050c3141f7f2f perhaps.

[Tim Graham]

For existing refresh_from_db() tests, look at ​tests/basic/tests.py. I can't reproduce a problem based on the details you provided.