in_bulk does not work with annotated fields, nor on foreign key

[Cody Towstik]

in_bulk does some checks about the fields on the model using the class _meta.
It does not consider that fields can be annotated, or exist on another related model.

However, the code that does all the processing seems like it could handle both cases.

In both cases, you can make the field distinct.

class Person(models.Model):
    email = models.CharField()

class Customer(models.Model):
    person = models.ForeignKey("Person")

emails_to_process = [ "a", "b", "c" ]

# annotate case
Customer.objects.annotate(
    email_lower=Lower("person__email")
).distinct(
    "email_lower"
).in_bulk(
    emails_to_process, fieldname="email_lower"
)

# foreign key case
Customer.objects.distinct("person__email").in_bulk(emails_to_process, fieldname="person__email)