How to query and append a list of users emails linked with a manytomany relation to other Model

Question

First please take a look on the data structure. there are Three models

class Partner(models.Model):
    name = models.CharField(max_length=100, blank=True, null=True)
    group = models.OneToOneField(
        Group, on_delete=models.DO_NOTHING, blank=True, null=True)

class CustomUser(AbstractUser):
    email = models.EmailField(_('email address'), unique=True)
    partner = models.ManyToManyField(
        Partner, blank=True)

class Quote(models.Model):
    partner = models.ManyToManyField(
        Partner, blank=True, related_name='quote_partners')

There can be multiple partners inside the Quote and CustomUser partner field. I want to make a list of users email who are linked with Partner inside the partner field set in the quote model. This is how I'm doing;

    quote = Quote.objects.get(id=id)
    partners = quote.partner.all()
    for partner in partners:
        recipient_list = []
        for user in CustomUser.objects.filter(groups__partner=partner):
            recipient_list.append(user.email)

Currently quote object has 3 partners and collectively 4 users linked to these partners then there should be 4 emails in the the recipient_list, But this returning empty array []. Please highlight what I'm doing wrong and how to fix it.

Answer 1

You can .filter(…) ^[Django-doc] with:

CustomUser.objects.filter(groups__partner__quote_partners__id=id)

This looks for CustomUsers linked to a Group linked to a Partner linked to a Quote with the given id.

You can query with:

CustomUser.objects.filter(partner__quote_partners__id=id)

To look for CustomUsers that have a related Partner that has a related Quote with id as primary key.