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)

[Natalia Bidart]

Hello Cody, thank you for your ticket. This seems to be a new feature request since the documentation says that in_bulk works with a unique field or a distinct field (I read this as model's own fields, not annotations nor related field's fields, since checking uniqueness there could get tricky/expensive).

For cases like this, the recommended path forward is to first propose and discuss the idea/request with the community and gain consensus. To do that, you could start a new conversation on the ​Django Forum, where you'll reach a wider audience and likely get extra feedback.

I'll close the ticket for now, but if there is a community agreement for the feature request, you are welcome to come back to the ticket and point to the forum topic, so we can then re-open it. For more details, please see ​the documented guidelines for requesting features.

Thanks!