Source code for server.utils

from __future__ import annotations

import inspect
import importlib

from typing import overload, Any, TypeVar



_T = TypeVar('_T')



@overload


def load_class(cls: type[_T]) -> type[_T]: ...

@overload
def load_class(cls: str) -> type[Any] | None: ...


def load_class(cls: type[Any] | str) -> type[Any] | None:
    """ Loads the given class from string (unless alrady a class). """

    if inspect.isclass(cls):
        return cls

    module_name, _, class_name = cls.rpartition('.')
    module = importlib.import_module(module_name)

    # FIXME: Why are we supplying a default return, when import_module
    #        already could fail? It seems better to always raise an
    #        exception when the class doesn't exist... It might also be
    #        worth to use __import__ so we get the same error we would
    #        get if we tried to do `from module_name import class_name`
    return getattr(module, class_name, None)


# HACK: Fix module name lookup for some namespace packages


def patch_morepath() -> None:
    import morepath.autosetup
    if hasattr(morepath.autosetup, '_onegov_patch'):
        return

    _get_module_name = morepath.autosetup.get_module_name  # type: ignore[attr-defined]

    def get_module_name(distribution: object) -> str:
        name = _get_module_name(distribution)
        if name.startswith('more_'):
            return 'more.' + name[5:]
        return name

    morepath.autosetup.get_module_name = get_module_name  # type: ignore[attr-defined]
    morepath.autosetup._onegov_patch = True  # type: ignore[attr-defined]