`mock.patch(..., autospec=True)` on a `functools.partialmethod` attribute produces a completely uncallable mock

Bug report

Bug description:

Autospeccing a class attribute that is a functools.partialmethod (either via mock.patch.object(cls, name, autospec=True) or mock.create_autospec(cls, ...) combined with a direct
mock.patch.object on that one attribute) produces a unittest.mock.NonCallableMagicMock. Calling it then raises TypeError: 'NonCallableMagicMock' object is not callable, even though the real attribute is perfectly callable (instance.method(...) works fine on the un-mocked class).

import functools
from unittest import mock

class Client:
    def _send_request(self, method, url):
        return method, url

    _send_post_request = functools.partialmethod(_send_request, "POST")

with mock.patch.object(Client, "_send_post_request", autospec=True) as m:
    print(type(m))  # <class 'unittest.mock.NonCallableMagicMock'>
    client = Client()
    client._send_post_request("https://example.com")
    # TypeError: 'NonCallableMagicMock' object is not callable

Root cause:

_patch.get_original() (Lib/unittest/mock.py) reads the attribute via target.__dict__[name] first, deliberately bypassing the descriptor protocol (this is needed to support patching descriptors like @property correctly). For a functools.partialmethod attribute, this yields the
raw partialmethod instance rather than the bound-callable object that getattr(instance, name) would produce.

functools.partialmethod objects are not themselves callable (they have no __call__; only __get__, since they are non-data descriptors meant to be resolved through attribute access):

>>> import functools, inspect
>>> p = functools.partialmethod(lambda self, a: None, 1)
>>> callable(p)
False
>>> inspect.signature(p)
Traceback (most recent call last):
  ...
TypeError: functools.partialmethod(<function <lambda> at 0x...>, 1, ) is not a callable object

CPython versions tested on:

3.12, but tested on main as well.

Operating systems tested on:

Linux

Linked PRs

• gh-153582

Issue xác định Lib/unittest/mock.py và _patch.get_original(); trước tiên hãy chạy bản tái hiện partialmethod và lần theo cách autospec xử lý descriptor thô. Hoàn tất nghĩa là việc patch thuộc tính với autospec tạo ra một mock có thể gọi được và lời gọi client được hiển thị không còn gây ra TypeError, kèm theo coverage hồi quy cho trường hợp này.