UnionType by design only allows object types as possible_types. The graphql spec places no such limit on unions:
Note that members of a union type need to be concrete object types; you can't create a union type out of interfaces or other unions.
http://graphql.org/learn/schema/#union-types
It's clear that it's only meant to outlaw those types and other types that can't have a value that is solely of that type.
UnionType by design only allows object types as possible_types. The graphql spec places no such limit on unions:
http://graphql.org/learn/schema/#union-types
It's clear that it's only meant to outlaw those types and other types that can't have a value that is solely of that type.