Prefetch with to_attr silently ignored if matching property exists

[dc-strahlkraft]

Minimal reproduction ​https://gitlab.com/Dan_Strahlkraft/django-prefetch

Given these models:

class Product(models.Model):
    @property
    def enabled_images(self):
        return self.images.filter(enabled=True)


class ProductImage(models.Model):
    product = models.ForeignKey(Product, models.PROTECT, related_name="images")
    enabled = models.BooleanField()

I want to eagerly load the enabled_images property so that it doesn't hit the database on access. So I write: Product.objects.prefetch_related(Prefetch("images", ProductImage.objects.filter(enabled=True), to_attr="enabled_images")). But that doesn't prefetch anything. The Prefetch is silently ignored.

The simplest workaround I can think of is:

class Product(models.Model):
    @property
    def enabled_images(self):
        try:
            return self.prefetched_enabled_images
        except AttributeError:
            return self.images.filter(enabled=True)

Then I can write Product.objects.prefetch_related(Prefetch("images", ProductImage.objects.filter(enabled=True), to_attr="prefetched_enabled_images")) and now accessing product.enabled_images won't hit the database, but I think it's uglier.