Horrible schema names in fastapi

Reusing pyndantic models with usage of type generics can cause horrible schema names in the resulting openapi spec.

This will show in your openapi spec as a schema named ResponseList_MyResponse_MyMetaResponse_:

@router.get("/myroute")
async def myroute() -> ResponseList[MyResponse, MyMetaResponse]:
    return Responselist(data=MyResponse(), meta=MyMetaResponse())

A quick fix can be add a definition of a model that extends your reusable base model.

from pydantic import BaseModel

class ResponseList[Data, Meta](BaseModel):
    data: list[Data]
    meta: Meta

class MyResponse(BaseModel):    
    id: str

class MyMetaResponse(BaseModel):    
    copyright: str    

class MyListResponse(
    ResponseList[MyResponse, MyMetaResponse]
):
    pass


@router.get("/myroute")
async def myroute() -> MyListResponse:
    return MyListResponse(data=[MyResponse()], meta=MyMetaResponse())