Graphene-django: AttributeError: 'NoneType' object has no attribute '_meta'

[aliev]

I have simple graphene based django project: https://github.com/aliev/graphene-django-bug

For some reason when I'm trying to run server or make migrations I have an exception:

AttributeError: 'NoneType' object has no attribute '_meta'

I'm using model forms and DjangoModelFormMutation

[tpict]

I'm having the same issue with the rest framework SerializerMutation

[ceelian]

same here, can't figure it out why this is happening.

[ceelian]

In my case the error originated from defining the SerializerMutation class before the Type class which I needed in the SerializerMutation. After moving all schema types above the mutations it worked.

[GitRon]

@ceelian How did you do it? I use separate files for types, queries etc.

Sound similar to my issue: https://github.com/graphql-python/graphene-django/issues/602

[PeterDekkers]

@phalt this bug is still current AFAIK. Not sure why this has been closed? To confirm, when putting mutations into a Python file separate from the type definitions I need to import all the types related to the mutations at the top of the file. Even though I don't use them. Otherwise AttributeError: 'NoneType' object has no attribute '_meta' is raised when running unit tests.

  File "/django-project/api/schema.py", line 42, in <module>
    schema = graphene.Schema(query=Query, mutation=Mutation)
  File "/usr/local/lib/python3.6/site-packages/graphene/types/schema.py", line 62, in __init__
    self.build_typemap()
  File "/usr/local/lib/python3.6/site-packages/graphene/types/schema.py", line 126, in build_typemap
    initial_types, auto_camelcase=self.auto_camelcase, schema=self
  File "/usr/local/lib/python3.6/site-packages/graphene/types/typemap.py", line 80, in __init__
    super(TypeMap, self).__init__(types)
  File "/usr/local/lib/python3.6/site-packages/graphql/type/typemap.py", line 28, in __init__
    self.update(reduce(self.reducer, types, OrderedDict()))  # type: ignore
  File "/usr/local/lib/python3.6/site-packages/graphene/types/typemap.py", line 88, in reducer
    return self.graphene_reducer(map, type)
  File "/usr/local/lib/python3.6/site-packages/graphene/types/typemap.py", line 117, in graphene_reducer
    return GraphQLTypeMap.reducer(map, internal_type)
  File "/usr/local/lib/python3.6/site-packages/graphql/type/typemap.py", line 106, in reducer
    field_map = type.fields
  File "/usr/local/lib/python3.6/site-packages/graphql/pyutils/cached_property.py", line 22, in __get__
    value = obj.__dict__[self.func.__name__] = self.func(obj)
  File "/usr/local/lib/python3.6/site-packages/graphql/type/definition.py", line 221, in fields
    return define_field_map(self, self._fields)
  File "/usr/local/lib/python3.6/site-packages/graphql/type/definition.py", line 235, in define_field_map
    field_map = field_map()
  File "/usr/local/lib/python3.6/site-packages/graphene/types/typemap.py", line 274, in construct_fields_for_type
    map = self.reducer(map, field.type)
  File "/usr/local/lib/python3.6/site-packages/graphene/types/typemap.py", line 88, in reducer
    return self.graphene_reducer(map, type)
  File "/usr/local/lib/python3.6/site-packages/graphene/types/typemap.py", line 117, in graphene_reducer
    return GraphQLTypeMap.reducer(map, internal_type)
  File "/usr/local/lib/python3.6/site-packages/graphql/type/typemap.py", line 106, in reducer
    field_map = type.fields
  File "/usr/local/lib/python3.6/site-packages/graphql/pyutils/cached_property.py", line 22, in __get__
    value = obj.__dict__[self.func.__name__] = self.func(obj)
  File "/usr/local/lib/python3.6/site-packages/graphql/type/definition.py", line 221, in fields
    return define_field_map(self, self._fields)
  File "/usr/local/lib/python3.6/site-packages/graphql/type/definition.py", line 235, in define_field_map
    field_map = field_map()
  File "/usr/local/lib/python3.6/site-packages/graphene/types/typemap.py", line 275, in construct_fields_for_type
    field_type = self.get_field_type(map, field.type)
  File "/usr/local/lib/python3.6/site-packages/graphene/types/typemap.py", line 333, in get_field_type
    return GraphQLList(self.get_field_type(map, type.of_type))
  File "/usr/local/lib/python3.6/site-packages/graphene/types/typemap.py", line 336, in get_field_type
    return map.get(type._meta.name)
AttributeError: 'NoneType' object has no attribute '_meta'

[PeterDekkers]

I've narrowed it down to that I need to import _only_ those types that have a relation (ForeignKey or OneToOne) to another type. Would you like me to provide a simple example to reproduce the issue, would that help?

[rafaph]

Same problem here, it happens when I define types in separate files.

[allen-munsch]

In my particular case I was missing some object type definitions.

By adding a print statement to construct_fields_for_type in class TypeMap:

nano +276 site-packages/graphene/types/typemap.py

    def construct_fields_for_type(self, map, type, is_input_type=False):
        fields = OrderedDict()
        for name, field in type._meta.fields.items():
            print(name) # added print statement here

I was able to determine which foreignkey fields were missing a type definition:

Not completely defined:

class SomethingWithForeignKeyNode(DjangoObjectType):
      class Meta:
           model = SomethingWithForeignKey

Added:

class SomeForeignKeyNode(DjangoObjectType):
    class Meta:
        model = SomeForeignKeyModel
        interfaces = (relay.Node,)
        filter_fields = []

[ghost]

(venv) E:\project\Ecommerce\Unboxxen\backend>python manage.py runserver 127.0.0.1:7000
Watching for file changes with StatReloader
INFO [2020-03-05 17:38:22,724] django.utils.autoreload: Watching for file changes with StatReloader
Performing system checks...

System check identified no issues (0 silenced).
March 05, 2020 - 17:38:22
Django version 3.0.3, using settings 'unboxxen.settings.local'
Starting development server at http://127.0.0.1:7000/
Quit the server with CTRL-BREAK.
Internal Server Error: /api/v1/users/
Traceback (most recent call last):
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\django\core\handlers\exception.py", line 34, in inner
response = get_response(request)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\django\core\handlers\base.py", line 115, in _get_response
response = self.process_exception_by_middleware(e, request)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\django\core\handlers\base.py", line 113, in _get_response
response = wrapped_callback(request, callback_args, *callback_kwargs)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\django\views\decorators\csrf.py", line 54, in wrapped_view
return view_func(args, *kwargs)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\django\views\generic\base.py", line 71, in view
return self.dispatch(request, args, *kwargs)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\views.py", line 505, in dispatch
response = self.handle_exception(exc)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\views.py", line 465, in handle_exception
self.raise_uncaught_exception(exc)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\views.py", line 476, in raise_uncaught_exception
raise exc
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\views.py", line 502, in dispatch
response = handler(request, args, *kwargs)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\generics.py", line 190, in post
return self.create(request, args, *kwargs)
File "E:\project\Ecommerce\Unboxxen\backendusers\views.py", line 16, in create
serializer.is_valid(raise_exception=True)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\serializers.py", line 234, in is_valid
self._validated_data = self.run_validation(self.initial_data)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\serializers.py", line 433, in run_validation
value = self.to_internal_value(data)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\serializers.py", line 486, in to_internal_value
for field in fields:
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\serializers.py", line 369, in _writable_fields
for field in self.fields.values():
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\django\utils\functional.py", line 48, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\serializers.py", line 363, in fields
for key, value in self.get_fields().items():
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\serializers.py", line 1037, in get_fields
info = model_meta.get_field_info(model)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\utils\model_meta.py", line 39, in get_field_info
forward_relations = _get_forward_relationships(opts)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\utils\model_meta.py", line 96, in _get_forward_relationships
not field.remote_field.through._meta.auto_created
AttributeError: 'NoneType' object has no attribute '_meta'
ERROR [2020-03-05 17:39:38,042] django.request: Internal Server Error: /api/v1/users/
Traceback (most recent call last):
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\django\core\handlers\exception.py", line 34, in inner
response = get_response(request)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\django\core\handlers\base.py", line 115, in _get_response
response = self.process_exception_by_middleware(e, request)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\django\core\handlers\base.py", line 113, in _get_response
response = wrapped_callback(request, callback_args, *callback_kwargs)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\django\views\decorators\csrf.py", line 54, in wrapped_view
return view_func(args, *kwargs)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\django\views\generic\base.py", line 71, in view
return self.dispatch(request, args, *kwargs)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\views.py", line 505, in dispatch
response = self.handle_exception(exc)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\views.py", line 465, in handle_exception
self.raise_uncaught_exception(exc)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\views.py", line 476, in raise_uncaught_exception
raise exc
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\views.py", line 502, in dispatch
response = handler(request, args, *kwargs)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\generics.py", line 190, in post
return self.create(request, args, *kwargs)
File "E:\project\Ecommerce\Unboxxen\backendusers\views.py", line 16, in create
serializer.is_valid(raise_exception=True)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\serializers.py", line 234, in is_valid
self._validated_data = self.run_validation(self.initial_data)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\serializers.py", line 433, in run_validation
value = self.to_internal_value(data)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\serializers.py", line 486, in to_internal_value
for field in fields:
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\serializers.py", line 369, in _writable_fields
for field in self.fields.values():
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\django\utils\functional.py", line 48, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\serializers.py", line 363, in fields
for key, value in self.get_fields().items():
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\serializers.py", line 1037, in get_fields
info = model_meta.get_field_info(model)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\utils\model_meta.py", line 39, in get_field_info
forward_relations = _get_forward_relationships(opts)
File "E:\project\Ecommerce\Unboxxen\venv\lib\site-packages\rest_framework\utils\model_meta.py", line 96, in _get_forward_relationships
not field.remote_field.through._meta.auto_created
AttributeError: 'NoneType' object has no attribute '_meta'
[05/Mar/2020 17:39:38] "POST /api/v1/users/ HTTP/1.1" 500 24231

Help me

[nrgx]

I've got the same error after splitting code base for queries, mutations and serializers. I was writing all into one module schema.py and it was under boilerplate code avalanche just for 5 models -> 5 query classes + 5 mutation classes and 5 serializer classes into mutation meta classes. I reset previous commits and it works just fine. I did this because returning this boilerplate code back manually caused the same error with _meta.
```

schema.py

import graphene
from graphene import relay
from graphene_django import DjangoObjectType, DjangoConnectionField
from graphene_django.rest_framework.mutation import SerializerMutation
from rest_framework.serializers import ModelSerializer
from .models import *

class CategoryNode(DjangoObjectType):
class Meta:
model = Category
interfaces = (relay.Node,)

class CategoryMutation(SerializerMutation):
class Meta:
class CategorySerializer(ModelSerializer):
class Meta:
model = Category
fields = '__all__'

    serializer_class = CategorySerializer

...

class Query:
categories = DjangoConnectionField(CategoryNode)
editions = DjangoConnectionField(EditionNode)
resources = DjangoConnectionField(ResourceNode)
reviews = DjangoConnectionField(ReviewNode)

category = graphene.relay.Node.Field(CategoryNode)
edition = graphene.relay.Node.Field(EditionNode)
resource = graphene.relay.Node.Field(ResourceNode)
review = graphene.relay.Node.Field(ReviewNode)

class Mutation:
category = CategoryMutation.Field()
edition = EditionMutation.Field()
resource = ReviewMutation.Field()
review = ReviewMutation.Field()

```
Idk but this seems legit for graphene_django

[nrgx]

Mmm no, I've mistaken. code split is legit. It's because SerializerMutation doesn't support nested serializers, like this:

class EmployeeMutation(SerializerMutation):
    class Meta:
        class EmployeeSerializer(ModelSerializer):
            member = OrganizationMemberSerializer(required=True)

            class Meta:
                model = Employee
                fields = '__all__'

        serializer_class = EmployeeSerializer

commenting out line with member = OrganizationMemberSerializer(required=True) and other nested writable serializers does not raise AttributeError: 'NoneType' object has no attribute '_meta'.

DRF's ModelSerializer allows writable nested serializers I want same in graphene_django

EDIT

Add node (or type whatever you called it) for nested serializer

class OrganizationMemberNode(DjangoObjectType):
    class Meta:
        model = OrganizationMember
        interfaces = (relay.Node,)


class EmployeeMutation(SerializerMutation):
    class Meta:
        class EmployeeSerializer(ModelSerializer):
            member = OrganizationMemberSerializer(required=True)

            class Meta:
                model = Employee
                fields = '__all__'

        serializer_class = EmployeeSerializer