Can't make a union of `gql.Connection | OperationMessage` (part 2)

[pomidoroshev]

Can't make a union of `gql.Connection | OperationMessage` (part 2)

[pomidoroshev]

I tried a naive fix with a test, and it turned out that there's another problem: StrawberryUnion can't match the types strawberry.types.types.Connection and FruitConnection and raises UnallowedReturnTypeForUnion:

  File "<...>/site-packages/strawberry/union.py", line 201, in _resolve_union_type
    raise UnallowedReturnTypeForUnion(
strawberry.exceptions.UnallowedReturnTypeForUnion: The type "<class 'strawberry.types.types.Connection'>" of the field "fruitsOrError" is not in the list of the types of the union: "['FruitConnection', 'OperationMessage']"

Github action log: https://github.com/pomidoroshev/strawberry-django-plus/actions/runs/5179448035/jobs/9332339724#step:7:952

[bellini666]

@pomidoroshev hrm, I overlooked that =P

You probably need to resolve the union the same way as in the other function above it. It is not great doing that twice, but I think it is not a major issue, specially because this PR should soon be merged and the way of resolving this will be greatly simplified.

Feel free to try to send a PR for that. Otherwise I will try to fix that tomorrow :)

[pomidoroshev]

@bellini666

You probably need to resolve the union the same way as in the other function above it.

Yep, I did that, just copy-pasted your solution pomidoroshev@7c21431#diff-bf0a824c6ab1aff4a9b72c271bc38ebeae4db3b82f27073eccfc2db59d34f534R1078-R1089

The problem happens afterwards, when the nodes are resolved, and Strawberry checks the actual returned types against the types inside the union. The union contains FruitConnection, the returned value is strawberry.types.types.Connection, and it causes UnallowedReturnTypeForUnion

[pomidoroshev]

I submitted a PR to illustrate the problem of UnallowedReturnTypeForUnion #226

[bellini666]

Hey @pomidoroshev ,

There's indeed something strange happening here..

Having said that, the relay PR got merged yesterday on strawberry and I'll try to refactor strawberrry-django-plus to use it this weekend. If everything goes accordingly to the plan, this issue will be solved as well.

[bellini666]

@pomidoroshev I just released the new version which uses the official integration. Could you check if it solves your issue?

[pomidoroshev]

@bellini666 Unfortunately, no. I haven't fixed the test in the related PR yet, but I tried on my own project.

The following code works fine:

from strawberry import relay
from strawberry_django_plus import gql
from strawberry_django_plus.permissions import IsAuthenticated
from strawberry_django_plus.types import OperationMessage

@gql.django.type(Profile)
class ProfileType(relay.Node):
    first_name: str
    last_name: str
    # ...

@gql.type
class ProfilesQuery:
    all_profiles: relay.ListConnection[ProfileType] = gql.django.connection(
        directives=[IsAuthenticated()]
    )

But if I add | OperationMessage, it raises TypeError: Query fields cannot be resolved.:

@gql.type
class ProfilesQuery:
    all_profiles: relay.ListConnection[ProfileType] | OperationMessage = gql.django.connection(
        directives=[IsAuthenticated()]
    )

Stack trace

    @cached_property
    def fields(self) -> GraphQLFieldMap:
        """Get provided fields, wrapping them as GraphQLFields if needed."""
        try:
>           fields = resolve_thunk(self._fields)

/<...>/python3.11/site-packages/graphql/type/definition.py:808: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

thunk = <function GraphQLCoreConverter.from_object.<locals>.<lambda> at 0x105e14c20>

    def resolve_thunk(thunk: Thunk[T]) -> T:
        """Resolve the given thunk.
    
        Used while defining GraphQL types to allow for circular references in otherwise
        immutable type definitions.
        """
>       return thunk() if callable(thunk) else thunk

/<...>/python3.11/site-packages/graphql/type/definition.py:300: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

>       fields=lambda: self.get_graphql_fields(object_type),
        interfaces=list(map(self.from_interface, object_type.interfaces)),
        description=object_type.description,
        is_type_of=_get_is_type_of(),
        extensions={
            GraphQLCoreConverter.DEFINITION_BACKREF: object_type,
        },
    )

/<...>/python3.11/site-packages/strawberry/schema/schema_converter.py:438: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <strawberry.schema.schema_converter.GraphQLCoreConverter object at 0x1059c94d0>
type_definition = TypeDefinition(name='Query', is_input=False, is_interface=False, origin=<class 'myproject.core.graphql.schema.Query'>, ...,hash=None,compare=True,metadata=mappingproxy({}),kw_only=True,_field_type=_FIELD)], concrete_of=None, type_var_map={})

    def get_graphql_fields(
        self, type_definition: TypeDefinition
    ) -> Dict[str, GraphQLField]:
>       return self._get_thunk_mapping(
            type_definition=type_definition,
            name_converter=self.config.name_converter.from_field,
            field_converter=self.from_field,
        )

/<...>/python3.11/site-packages/strawberry/schema/schema_converter.py:327: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

type_definition = TypeDefinition(name='Query', is_input=False, is_interface=False, origin=<class 'myproject.core.graphql.schema.Query'>, ...,hash=None,compare=True,metadata=mappingproxy({}),kw_only=True,_field_type=_FIELD)], concrete_of=None, type_var_map={})
name_converter = <bound method NameConverter.from_field of <strawberry.schema.name_converter.NameConverter object at 0x1059ca650>>
field_converter = <bound method GraphQLCoreConverter.from_field of <strawberry.schema.schema_converter.GraphQLCoreConverter object at 0x1059c94d0>>

    @staticmethod
    def _get_thunk_mapping(
        type_definition: TypeDefinition,
        name_converter: Callable[[StrawberryField], str],
        field_converter: Callable[[StrawberryField], FieldType],
    ) -> Dict[str, FieldType]:
        """Create a GraphQL core `ThunkMapping` mapping of field names to field types.
    
        This method filters out remaining `strawberry.Private` annotated fields that
        could not be filtered during the initialization of a `TypeDefinition` due to
        postponed type-hint evaluation (PEP-563). Performing this filtering now (at
        schema conversion time) ensures that all types to be included in the schema
        should have already been resolved.
    
        Raises:
            TypeError: If the type of a field in ``fields`` is `UNRESOLVED`
        """
        thunk_mapping = {}
    
        for field in type_definition.fields:
            if field.type is UNRESOLVED:
                raise UnresolvedFieldTypeError(type_definition, field)
    
            if not is_private(field.type):
>               thunk_mapping[name_converter(field)] = field_converter(field)

/<...>/python3.11/site-packages/strawberry/schema/schema_converter.py:320: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <strawberry.schema.schema_converter.GraphQLCoreConverter object at 0x1059c94d0>
field = Field(name='all_profiles',type=<strawberry.union.StrawberryUnion object at 0x1061bf290>,default=<dataclasses._MISSING_...t at 0x101617bd0>,init=True,repr=True,hash=None,compare=True,metadata=mappingproxy({}),kw_only=True,_field_type=_FIELD)

    def from_field(self, field: StrawberryField) -> GraphQLField:
        # self.from_resolver needs to be called before accessing field.type because
        # in there a field extension might want to change the type during its apply
>       resolver = self.from_resolver(field)

/<...>/python3.11/site-packages/strawberry/schema/schema_converter.py:250: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <strawberry.schema.schema_converter.GraphQLCoreConverter object at 0x1059c94d0>
field = Field(name='all_profiles',type=<strawberry.union.StrawberryUnion object at 0x10622c810>,default=<dataclasses._MISSING_...t at 0x101617bd0>,init=True,repr=True,hash=None,compare=True,metadata=mappingproxy({}),kw_only=True,_field_type=_FIELD)

    def from_resolver(
        self, field: StrawberryField
    ) -> Callable:  # TODO: Take StrawberryResolver
        field.default_resolver = self.config.default_resolver
    
        if field.is_basic_field:
    
            def _get_basic_result(_source: Any, *args: str, **kwargs: Any):
                # Call `get_result` without an info object or any args or
                # kwargs because this is a basic field with no resolver.
                return field.get_result(_source, info=None, args=[], kwargs={})
    
            _get_basic_result._is_default = True  # type: ignore
    
            return _get_basic_result
    
        def _get_arguments(
            source: Any,
            info: Info,
            kwargs: Any,
        ) -> Tuple[List[Any], Dict[str, Any]]:
            # TODO: An extension might have changed the resolver arguments,
            # but we need them here since we are calling it.
            # This is a bit of a hack, but it's the easiest way to get the arguments
            # This happens in mutation.InputMutationExtension
            field_arguments = field.arguments[:]
            if field.base_resolver:
                existing = {arg.python_name for arg in field_arguments}
                field_arguments.extend(
                    [
                        arg
                        for arg in field.base_resolver.arguments
                        if arg.python_name not in existing
                    ]
                )
    
            kwargs = convert_arguments(
                kwargs,
                field_arguments,
                scalar_registry=self.scalar_registry,
                config=self.config,
            )
    
            # the following code allows to omit info and root arguments
            # by inspecting the original resolver arguments,
            # if it asks for self, the source will be passed as first argument
            # if it asks for root, the source it will be passed as kwarg
            # if it asks for info, the info will be passed as kwarg
    
            args = []
    
            if field.base_resolver:
                if field.base_resolver.self_parameter:
                    args.append(source)
    
                root_parameter = field.base_resolver.root_parameter
                if root_parameter:
                    kwargs[root_parameter.name] = source
    
                info_parameter = field.base_resolver.info_parameter
                if info_parameter:
                    kwargs[info_parameter.name] = info
    
            return args, kwargs
    
        def _check_permissions(source: Any, info: Info, kwargs: Any):
            """
            Checks if the permission should be accepted and
            raises an exception if not
            """
            for permission_class in field.permission_classes:
                permission = permission_class()
    
                if not permission.has_permission(source, info, **kwargs):
                    message = getattr(permission, "message", None)
                    raise PermissionError(message)
    
        async def _check_permissions_async(source: Any, info: Info, kwargs: Any):
            for permission_class in field.permission_classes:
                permission = permission_class()
                has_permission: bool
    
                has_permission = await await_maybe(
                    permission.has_permission(source, info, **kwargs)
                )
    
                if not has_permission:
                    message = getattr(permission, "message", None)
                    raise PermissionError(message)
    
        def _strawberry_info_from_graphql(info: GraphQLResolveInfo) -> Info:
            return Info(
                _raw_info=info,
                _field=field,
            )
    
        def _get_result(
            _source: Any,
            info: Info,
            field_args: List[Any],
            field_kwargs: Dict[str, Any],
        ):
            return field.get_result(
                _source, info=info, args=field_args, kwargs=field_kwargs
            )
    
        def wrap_field_extensions() -> Callable[..., Any]:
            """Wrap the provided field resolver with the middleware."""
    
            for extension in field.extensions:
                extension.apply(field)
    
            extension_functions = build_field_extension_resolvers(field)
    
            def extension_resolver(
                _source: Any,
                info: Info,
                **kwargs: Any,
            ):
                # parse field arguments into Strawberry input types and convert
                # field names to Python equivalents
                field_args, field_kwargs = _get_arguments(
                    source=_source, info=info, kwargs=kwargs
                )
    
                resolver_requested_info = False
                if "info" in field_kwargs:
                    resolver_requested_info = True
                    # remove info from field_kwargs because we're passing it
                    # explicitly to the extensions
                    field_kwargs.pop("info")
    
                # `_get_result` expects `field_args` and `field_kwargs` as
                # separate arguments so we have to wrap the function so that we
                # can pass them in
                def wrapped_get_result(_source: Any, info: Info, **kwargs: Any):
                    # if the resolver function requested the info object info
                    # then put it back in the kwargs dictionary
                    if resolver_requested_info:
                        kwargs["info"] = info
    
                    return _get_result(
                        _source, info, field_args=field_args, field_kwargs=kwargs
                    )
    
                # combine all the extension resolvers
                return reduce(
                    lambda chained_fn, next_fn: partial(next_fn, chained_fn),
                    extension_functions,
                    wrapped_get_result,
                )(_source, info, **field_kwargs)
    
            return extension_resolver
    
>       _get_result_with_extensions = wrap_field_extensions()

/<...>/python3.11/site-packages/strawberry/schema/schema_converter.py:607: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

    def wrap_field_extensions() -> Callable[..., Any]:
        """Wrap the provided field resolver with the middleware."""
    
        for extension in field.extensions:
>           extension.apply(field)

/<...>/python3.11/site-packages/strawberry/schema/schema_converter.py:563: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <strawberry_django_plus.field.StrawberryDjangoConnectionExtension object at 0x1058da8d0>
field = Field(name='all_profiles',type=<strawberry.union.StrawberryUnion object at 0x10622cad0>,default=<dataclasses._MISSING_...t at 0x101617bd0>,init=True,repr=True,hash=None,compare=True,metadata=mappingproxy({}),kw_only=True,_field_type=_FIELD)

    def apply(self, field: StrawberryDjangoField) -> None:
        # NOTE: Because we have a base_resolver defined, our parents will not add
        # order/filters resolvers in here, so we need to add them by hand (unless they
        # are somewhat in there). We are not adding pagination because it doesn't make
        # sense together with a Connection
>       args_names = {a.python_name for a in field.arguments}

/<...>/python3.11/site-packages/strawberry_django_plus/field.py:345: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = Field(name='all_profiles',type=<strawberry.union.StrawberryUnion object at 0x10622cf50>,default=<dataclasses._MISSING_...t at 0x101617bd0>,init=True,repr=True,hash=None,compare=True,metadata=mappingproxy({}),kw_only=True,_field_type=_FIELD)

    @property
    def arguments(self) -> List[StrawberryArgument]:
>       args = super().arguments

/<...>/python3.11/site-packages/strawberry_django_plus/field.py:99: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = Field(name='all_profiles',type=<strawberry.union.StrawberryUnion object at 0x10650d5d0>,default=<dataclasses._MISSING_...t at 0x101617bd0>,init=True,repr=True,hash=None,compare=True,metadata=mappingproxy({}),kw_only=True,_field_type=_FIELD)

    @property
    def arguments(self) -> List[StrawberryArgument]:
        arguments = []
        if not self.base_resolver:
            pagination = self.get_pagination()
            if pagination and pagination is not UNSET:
                arguments.append(argument("pagination", OffsetPaginationInput))
>       return super().arguments + arguments

/<...>/python3.11/site-packages/strawberry_django/pagination.py:40: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = Field(name='all_profiles',type=<strawberry.union.StrawberryUnion object at 0x10650da90>,default=<dataclasses._MISSING_...t at 0x101617bd0>,init=True,repr=True,hash=None,compare=True,metadata=mappingproxy({}),kw_only=True,_field_type=_FIELD)

    @property
    def arguments(self) -> List[StrawberryArgument]:
        arguments = []
        if not self.base_resolver:
>           order = self.get_order()

/<...>/python3.11/site-packages/strawberry_django/ordering.py:69: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = Field(name='all_profiles',type=<strawberry.union.StrawberryUnion object at 0x1065e1cd0>,default=<dataclasses._MISSING_...t at 0x101617bd0>,init=True,repr=True,hash=None,compare=True,metadata=mappingproxy({}),kw_only=True,_field_type=_FIELD)

    def get_order(self) -> Optional[Type]:
        # FIXME: This should be done on strawberry-graphql-django
        order = super().get_order()
        if order in (None, UNSET):
>           t_origin = self.type_origin

/<...>/python3.11/site-packages/strawberry_django_plus/field.py:154: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <functools.cached_property object at 0x1045b9f90>
instance = Field(name='all_profiles',type=<strawberry.union.StrawberryUnion object at 0x1065e1ed0>,default=<dataclasses._MISSING_...t at 0x101617bd0>,init=True,repr=True,hash=None,compare=True,metadata=mappingproxy({}),kw_only=True,_field_type=_FIELD)
owner = <class 'strawberry_django_plus.field.StrawberryDjangoField'>

    def __get__(self, instance, owner=None):
        if instance is None:
            return self
        if self.attrname is None:
            raise TypeError(
                "Cannot use cached_property instance without calling __set_name__ on it.")
        try:
            cache = instance.__dict__
        except AttributeError:  # not all objects have __dict__ (e.g. class defines slots)
            msg = (
                f"No '__dict__' attribute on {type(instance).__name__!r} "
                f"instance to cache {self.attrname!r} property."
            )
            raise TypeError(msg) from None
        val = cache.get(self.attrname, _NOT_FOUND)
        if val is _NOT_FOUND:
            with self.lock:
                # check if another thread filled cache while we awaited lock
                val = cache.get(self.attrname, _NOT_FOUND)
                if val is _NOT_FOUND:
>                   val = self.func(instance)

/<...>/lib/python3.11/functools.py:1001: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = Field(name='all_profiles',type=<strawberry.union.StrawberryUnion object at 0x1065e1dd0>,default=<dataclasses._MISSING_...t at 0x101617bd0>,init=True,repr=True,hash=None,compare=True,metadata=mappingproxy({}),kw_only=True,_field_type=_FIELD)

    @cached_property
    def type_origin(self) -> Type:
        origin = self.type
    
        tdef = cast(Optional[TypeDefinition], getattr(origin, "_type_definition", None))
        if tdef and tdef.concrete_of and issubclass(tdef.concrete_of.origin, relay.Connection):
            origin = tdef.type_var_map[relay.NodeType]  # type: ignore
            if isinstance(origin, LazyType):
                origin = origin.resolve_type()
    
        while isinstance(origin, StrawberryContainer):
            origin = origin.of_type
    
        if isinstance(origin, StrawberryUnion):
            olist = []
            for t in origin.types:
                while isinstance(t, StrawberryContainer):
                    t = t.of_type  # noqa: PLW2901
    
                if hasattr(t, "_django_type"):
                    olist.append(t)
    
>           assert len(olist) == 1
E           AssertionError

/<...>/python3.11/site-packages/strawberry_django_plus/field.py:192: AssertionError

The above exception was the direct cause of the following exception:

    @pytest.fixture()
    def graphql_url():
>       return reverse("graphql")

../../../../pytest_plugins/graphql.py:8: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
/<...>/python3.11/site-packages/django/urls/base.py:88: in reverse
    return resolver._reverse_with_prefix(view, prefix, *args, **kwargs)
/<...>/python3.11/site-packages/django/urls/resolvers.py:746: in _reverse_with_prefix
    self._populate()
/<...>/python3.11/site-packages/django/urls/resolvers.py:543: in _populate
    for url_pattern in reversed(self.url_patterns):
/<...>/python3.11/site-packages/django/utils/functional.py:57: in __get__
    res = instance.__dict__[self.name] = self.func(instance)
/<...>/python3.11/site-packages/django/urls/resolvers.py:715: in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
/<...>/python3.11/site-packages/django/utils/functional.py:57: in __get__
    res = instance.__dict__[self.name] = self.func(instance)
/<...>/python3.11/site-packages/django/urls/resolvers.py:708: in urlconf_module
    return import_module(self.urlconf_name)
/<...>/lib/python3.11/importlib/__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
../../../../urls.py:6: in <module>
    from myproject.core.graphql.schema import schema
../../../graphql/schema.py:39: in <module>
    schema = Schema(
/<...>/python3.11/site-packages/strawberry/schema/schema.py:140: in __init__
    self._schema = GraphQLSchema(
/<...>/python3.11/site-packages/graphql/type/schema.py:224: in __init__
    collect_referenced_types(query)
/<...>/python3.11/site-packages/graphql/type/schema.py:432: in collect_referenced_types
    for field in named_type.fields.values():
/<...>/lib/python3.11/functools.py:1001: in __get__
    val = self.func(instance)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <GraphQLObjectType 'Query'>

    @cached_property
    def fields(self) -> GraphQLFieldMap:
        """Get provided fields, wrapping them as GraphQLFields if needed."""
        try:
            fields = resolve_thunk(self._fields)
        except Exception as error:
            cls = GraphQLError if isinstance(error, GraphQLError) else TypeError
>           raise cls(f"{self.name} fields cannot be resolved. {error}") from error
E           TypeError: Query fields cannot be resolved.

/<...>/python3.11/site-packages/graphql/type/definition.py:811: TypeError

[pomidoroshev]

Since the relay mode is a native Strawberry feature, I tested it there and submitted an issue as well strawberry-graphql/strawberry#2893

[bellini666]

@pomidoroshev was actually going to comment that here :)

Let's continue this discussion there