DjangoObjectType Generates Wrong Schema on Arrayfield

Description

Get wrong result for python manage.py graphql_schema. Here’s an example repo which can make it more clear: https://github.com/helloqiu/graphene_bug_example

If I define the model as followed:

from django.db import models
from django.contrib.postgres.fields import ArrayField


class Example(models.Model):
    simple_array = ArrayField(models.CharField(max_length=255))

and write the schema like this:

from graphene_django import DjangoObjectType
import graphene

from graphene_bug_example.models import Example as ExampleModel


class Example(DjangoObjectType):
    required_field = graphene.String(required=True)

    class Meta:
        model = ExampleModel


class Query(graphene.ObjectType):
    examples = graphene.List(Example)

schema = graphene.Schema(query=Query)

then run python manage.py graphql_schema, the String in simpleArray, which is an ArrayField, is nullable:

...
            {
              "name": "simpleArray",
              "description": "",
              "args": [],
              "type": {
                "kind": "NON_NULL",
                "name": null,
                "ofType": {
                  "kind": "LIST",
                  "name": null,
                  "ofType": {
                    "kind": "SCALAR",
                    "name": "String",
                    "ofType": null
                  }
                }
              },
              "isDeprecated": false,
              "deprecationReason": null
            },
...

Possible Solution

@convert_django_field.register(ArrayField)
def convert_postgres_array_to_list(field, registry=None):
    base_type = convert_django_field(field.base_field)
    if not isinstance(base_type, (List, NonNull)):
        base_type = type(base_type)
    return List(base_type, description=field.help_text, required=not field.null)

https://github.com/graphql-python/graphene-django/blob/master/graphene_django/converter.py#L212 I think we should restore required parameter after base_type = type(base_type). Something like this:

...
    if not isinstance(base_type, (List, NonNull)):
        base_type = type(base_type) if not base_type.kwargs['required'] else NonNull(type(base_type))
...

Maybe I will create a PR if this is verified as a bug by the maintainer.

[helloqiu]

Can’t wait to make a PR. 😃

[Archivec]

Same issue exists for DjangoFormMutation with postgres SimpleArrayField as a form field. The generated schema results in a string.

from django.contrib.postgres.forms import SimpleArrayField


class SampleForm(forms.Form):
    array_string = SimpleArrayField(forms.CharField(max_length=128))

class SampleMutation(DjangoFormMutation):
    output = String()
    
    @classmethod
    def perform_mutate(cls, form, info):
        ...

input SampleMutationInput {
    arrayString: String!
}

Solution

Similar to OP’s solution for model field, but instead uses graphene_django.forms.converter to register the form field.