Strawberry Base Before Model Error

Description

This error is thrown when a strawberry.pydantic type, input or interface extends a regular Strawberry type, input or interface before its Pydantic model, for example the following code will throw this error:

import pydantic
import strawberry


@strawberry.interface
class Node:
    id: strawberry.ID


@strawberry.pydantic.type
class Product(Node, pydantic.BaseModel):
    name: str  

Regular Strawberry types are dataclasses, so Node has its own __init__ . As Node comes before pydantic.BaseModel in Product ’s bases, its __init__ would replace Pydantic’s, and creating a Product would fail.

How to fix this error

You can fix this error by listing the Pydantic model first:

import pydantic
import strawberry


@strawberry.interface
class Node:
    id: strawberry.ID


@strawberry.pydantic.type
class Product(pydantic.BaseModel, Node):
    name: str