name: str


class RecursiveItemViaSubmodel(BaseModel):
    sub_items1: list[RecursiveSubitemInSubmodel] = []
    name: str


RecursiveItem.model_rebuild()
RecursiveSubitemInSubmodel.model_rebuild()
RecursiveItemViaSubmodel.model_rebuild()


@app.get("/items/recursive", response_model=RecursiveItem)
def get_recursive():
    return {"name": "item", "sub_items": [{"name": "subitem", "sub_items": []}]}