Generic Union Types

[HopeBaron]

Feature Request Type

• [ ] Core functionality
• [ ] Alteration (enhancement/optimization) of existing feature(s)
• [x] New behavior

Description

It would be nice to be able to make a generic union type to allow Success | Failure union types currently this won't work:

@strawberry.type(model.Error, all_fields=True)
class ErrorType:
    pass


T = TypeVar("T")

Result = strawberry.union("Result", (T, ErrorType))

As noted by @Doctor#7942 on Discord (couldn't mention in the issue) it's possible to achieve desired results using Pydantic as follows:

from typing import TypeVar, Union


class Error:
    pass


T = TypeVar("T")

TOrError = Union[T, Error]

int_or_error: TOrError[int] = 42

A reproducible example made by @patrick91 on Strawberry Playground

Original discussion