Resolver Field On Input Error

Description

This error is thrown when a field of an input type has a resolver, for example the following code will throw this error:

import strawberry


@strawberry.input
class UserInput:
    name: str

    @strawberry.field
    def upper_name(self) -> str:
        return self.name.upper()

This happens because input types only hold the values sent by the client, so their fields can’t be resolved: the resolver would never run, and every request using the input would fail, as the field can’t be passed to the input type.

The same applies to fields inherited from an output type, like in class UserInput(User) , when User has fields with resolvers.

How to fix this error

You can fix this error by removing the resolver, or by moving the field to an output type:

import strawberry


@strawberry.input
class UserInput:
    name: str


@strawberry.type
class User:
    name: str

    @strawberry.field
    def upper_name(self) -> str:
        return self.name.upper()

When the field is inherited, move the fields to share to a base type without resolvers, and inherit from it in both types:

import strawberry


@strawberry.type
class UserBase:
    name: str


@strawberry.type
class User(UserBase):
    @strawberry.field
    def upper_name(self) -> str:
        return self.name.upper()


@strawberry.input
class UserInput(UserBase):
    pass

Pydantic inputs

strawberry.pydantic.input raises this error too, for fields with a resolver defined on the input model:

import pydantic
import strawberry


@strawberry.pydantic.input
class UserInput(pydantic.BaseModel):
    name: str

    @strawberry.pydantic.field
    def upper_name(self) -> str:
        return self.name.upper()

Fields with a resolver inherited from a base model, for example one shared with an output type, are ignored by Pydantic inputs, so they don’t raise this error:

import pydantic
import strawberry


class UserBase(pydantic.BaseModel):
    name: str

    @strawberry.pydantic.field
    def upper_name(self) -> str:
        return self.name.upper()


@strawberry.pydantic.type
class User(UserBase):
    pass


@strawberry.pydantic.input
class UserInput(UserBase):
    pass