[BUG] Endpoint with query schema crashes when paginated and from __future__ import annotations import included

[jjnesbitt]

Apologies for the lengthy title.

Describe the bug
I get the following error on application start:

NameError: name 'MySchema' is not defined

If the following conditions are met:

1. An endpoint function is defined with the paginate decorator
2. There is an argument to the function that is a user defined query param schema (Query[MySchema])
3. The from __future__ import annotations import is present in the file

If any of these three things are excluded, the bug does not occur.

Versions (please complete the following information):

• Python versions tested: 3.11, 3.12, 3.13
• Django version: 5.1.6
• Django-Ninja version: 1.3.0
• Pydantic version: 2.10.6

Here is an MRE:

from __future__ import annotations

from ninja import NinjaAPI, Query, Schema
from ninja.pagination import PageNumberPagination, paginate


class MySchema(Schema):
    foo: str


api = NinjaAPI()


@api.get("/endpoint_path", response=list[int])
@paginate(PageNumberPagination)
def atpath(
    request,
    params: Query[MySchema],
):
    return []

[jjnesbitt]

This seems similar to #1357, but I don't think these are duplicate issues.

[vitalik]

Hi @jjnesbitt

there is some dark magic with evaulate forward refs in pydantic that I do not fully understand - but for now you can try this branch #1425 (1424-evaluate-forward-ref)

[jjnesbitt]

Hi @vitalik, has this been fixed via #1425?

[benf710]

I'm still able to reproduce this error with Django Ninja 1.4.1. I was able to work around this issue by overriding globals using a custom @paginate decorator:

def repair_wrapped_globalns(
    f: Callable[..., Any],
    globalns: dict[str, Any] | None = None,
    module: str | None = None,
):
    """Use this to generate a new function with an updated global namespace.

    Credit: https://stackoverflow.com/a/49077211
    """

    if globalns is None:
        globalns = f.__globals__

    g = types.FunctionType(
        f.__code__,
        globalns,
        name=f.__name__,
        argdefs=f.__defaults__,
        closure=f.__closure__,
    )

    g = functools.update_wrapper(g, f)

    if module is not None:
        g.__module__ = module

    g.__kwdefaults__ = copy.copy(f.__kwdefaults__)  # pyright: ignore[reportAttributeAccessIssue]

    return g


def paginate(func_or_pgn_class: Any = NOT_SET, **paginator_params: DictStrAny) -> Callable[..., Any]:
    """Custom `@paginate` decorator because, in brief, the current version of Django Ninja doesn't handle
    globals correctly when resolving type signatures.

    NOTE: The ninja.conf import has to be within this function for `import_string(settings.PAGINATION_CLASS)`
    to work correctly.
    """

    from ninja.conf import settings

    isfunction = inspect.isfunction(func_or_pgn_class)
    isnotset = func_or_pgn_class == NOT_SET

    pagination_class: type[PaginationBase] = import_string(settings.PAGINATION_CLASS)

    # ! This condition is where the source code has been modified.
    if isfunction:
        ret = _inject_pagination(func_or_pgn_class, pagination_class)
        ret = repair_wrapped_globalns(ret, func_or_pgn_class.__globals__, func_or_pgn_class.__name__)
        return ret

    if not isnotset:
        pagination_class = func_or_pgn_class

    def wrapper(func: Callable[..., Any]) -> Any:
        return _inject_pagination(func, pagination_class, **paginator_params)

    return wrapper