Schema incorrectly typing ManyToMany field

Hi,

I’m new to graphene (and django, really) but have come across a stumbling block.

I have the following django models:

class Person(models.Model):
    name = models.CharField(max_length=100, blank=False)

class Booking(models.Model):
    people = models.ManyToManyField(Person, related_name="bookings", blank=False)

One person has many bookings; one booking has many people.

Then I have the following object types in my graphene schema:

class PersonType(DjangoObjectType):
    class Meta:
        model = Person

class BookingType(DjangoObjectType):
    class Meta:
        model = Booking

class Query(graphene.AbstractType):
    all_people = graphene.List(PeopleType)
    all_bookings = graphene.List(BookingType)

    def resolve_all_people(self, *args, **kwargs):
        return Person.objects.all()

    def resolve_all_bookings(self, *args, **kwargs):
        return Booking.objects.all()

everything else is boilerplate from the graphene/django getting started tutorials.

When I make my query with graphiql:

{
  allBookings {
    people {
      id
    }
  }
}

I get the following error:

{
  "errors": [
    {
      "message": "Expected value of type \"BookingType\" but got: Person.",
      "locations": [
        {
          "line": 3,
          "column": 5
        }
      ]
    }
  ],
  "data": {
    "allBookings": [
      {
        "people": [
          null
        ]
      }
    ]
  }
}

Any ideas what i’m doing wrong? all my other foreign key (one-to-many) relations work fine out of the box. Also; if I query for a person’s bookings then it works fine too. Just when I query for a booking’s people do I get the error.

[grimborg]

Adding a resolver for the m2m field may be a simpler workaround.

class BookingType(DjangoObjectType):
    people = graphene.List(PersonType)

    @graphene.resolve_only_args
    def resolve_people(self):
        return self.people.all()

    class Meta:
        model = Booking

[LegoStormtroopr]

I don’t think you are doing anything wrong. I came up against a similar issue, however I was using a through model. Take this terribly contrived example:

class Person(models.Model):
    name = models.CharField(max_length=100, blank=False)

class BookingPersonRelation(models.Model)
    person = models.ForeignKey('Person')
    booking = models.ForeignKey('Booking')

class Booking(models.Model):
    people = models.ManyToManyField(Person, through=BookingPersonRelation, related_name="bookings")

I got the resolution to work, only once the intermediate model had a type

class BookingPersonRelationType(DjangoObjectType):
    class Meta:
        model = BookingPersonRelationType

Long term, I’m not sure what the resolution is - but if you can figure out how to get the generated ManyToMany model, you can probably create a type over that. I just started using this, but will no doubt run into the same problem and will come back with more info.