Strawberry GraphQL @ 0.330.3

Released

This release fixes classmethod resolvers inherited by a subclass being called with the class that defined them as cls , instead of the subclass. For example, { dog { says } } now returns "Dog says woof" , and so does Dog.says() : 

from typing import ClassVar


import strawberry




@strawberry.type
class Animal:
    sound: ClassVar[str] = "..."


    @strawberry.field
    @classmethod
    def says(cls) -> str:
        return f"{cls.__name__} says {cls.sound}"




@strawberry.type
class Dog(Animal):
    sound: ClassVar[str] = "woof"

cls is now always the type using the field, both when resolving a query and when the resolver is called from Python. This includes types implementing an interface, subclasses of generic types, types created with merge_types , and fields reused in another type, like with create_type or with an Annotated alias used by several types. A classmethod resolver reused in another type therefore no longer sees the class attributes of the type that defined it.

To do this, each type gets its own copy of an inherited field with a classmethod resolver, so the field in Dog.__strawberry_definition__ is no longer the same object as the one in Animal.__strawberry_definition__ , or as the one that dataclasses.fields(Dog) returns, which stays bound to Animal . The copy is made with copy.copy , like the copies Strawberry already makes of the fields of generic types, so custom StrawberryField subclasses with their own state need to implement __copy__ to keep it.

It also fixes inherited staticmethod resolvers called on an instance of the subclass, like Dog().helper() , which raised a TypeError .

This release was contributed by @patrick91 in https://github.com/strawberry-graphql/strawberry/pull/4662