Default filters for foreign keys should document as integers, not strings.

[dragonpaw]

Given a Django model with a FK that is an integer, the openapi documentation shows the filter as taking a string argument, not an integer.

Given:

# models.py
class That(models.Model):
    pk = models.IntegerField(primary=True)

class This(models.Model):
    that = models.ForeignKey('That')

# views.py
class ThisFilter(filters.FilterSet):
    class Meta:
        model = models.This
        fields = {
            "that": ["exact"]
        }

The resulting openapi/swagger docs will have a data type of string for the "that" filter, not integer, which is what I'd think it should be, as we're searching for an integer PK after all. Passing in just the int, unquoted, seems to work fine, so I think this is just documentation, not an actual filter issue.

[foarsitter]

Looking to the source that may be not a surprise since all the filter fields are hard coded as string.

What would be the preferred way for django-filter to implement the correct OpenAPI specification?

• Add the definition to the corresponding fields (i.e. field.get_schema_operation_parameters)
• Create a custom backend in a 3rd party package (dictionary between filter field and OpenAPI spec)

Either way, I'm happily give it a try!

[carltongibson]

Moving to #1432