Optional federated type

When I want to return a type that has required fields or None unexpected error is thrown

Here https://github.com/mirumee/ariadne/blob/0.12.0/tests/federation/test_schema.py#L431-L469 you have a test that works correctly. However, when you’ll change type fields to the required test will fail with error:

[GraphQLError('Cannot return null for non-nullable field Product.name.', locations=[SourceLocation(line=6, column=25)], path=['_entities', 0, 'name'])]

Test to reproduce:

def test_federated_schema_execute_reference_resolver_that_returns_none():
    type_defs = """
        type Query {
            rootField: String
        }
        type Product @key(fields: "upc") {
            upc: Int!
            name: String!
        }
    """

    product = FederatedObjectType("Product")

    @product.reference_resolver()
    def product_reference_resolver(_obj, _info, reference):
        assert reference["upc"] == 1
        # return None

    schema = make_federated_schema(type_defs, product)

    result = graphql_sync(
        schema,
        """
            query GetEntities($representations: [_Any!]!) {
                _entities(representations: $representations) {
                    ... on Product {
                        __typename
                        name
                    }
                }
            }
        """,
        variable_values={"representations": [{"__typename": "Product", "upc": 1,},],},
    )

    assert result.errors is None
    assert result.data["_entities"][0]["__typename"] == "Product"
    assert result.data["_entities"][0]["name"] is None

[rafalp]

@kamilglod it was released 4.5 hours ago, enjoy!

[kamilglod]

Indeed, master branch version works correctly! 😃 When you’re planning to release 0.13?