Bug: `return_dto` is silently ignored if return data type does not match DTO definition about litestar HOT 1 OPEN

This isn't a bug, as DTOs can be defined on layers, and it would be quite restrictive to only allow routes beneath a layer that has a dto defined, to only return that DTO supported type. For example:

class MyController(Controller):
    return_dto = SomeDTO[SomeType]

    @get("/{id:int}")
    def get_handler(self) -> SomeType: ...

    @get("/")
    def list_handler(self) -> list[SomeType]: ...

    @delete("/{id:int}")
    def delete_handler(self) -> None: ...

In that example, the delete handler not returning a model instance shouldn't force the user to have to define the dto individually on all of the other handlers.

I can perhaps see some utility to raising an error if a dto is defined directly on a handler as in your example, and that handler doesn't utilise it - but strictly speaking, having a dto available for a handler, but not required to be used is a design decision.

from litestar.