Description

rileyjohngibbs

opened on Mar 23, 2023

Issue body actions

Bug report

Using patch with autospec=True does not work when a method is decorated with @classmethod or @staticmethod. The resulting mock can be called with any arguments without raising a TypeError.

Example:

from unittest.mock import patch
import pytest

class Foo:
    def foo(self):
        pass
    @staticmethod
    def bar():
        pass
    @classmethod
    def baz(cls):
        pass

@pytest.mark.parametrize("method", ["foo", "bar", "baz"])
def test_foo(method: str):
    with patch.object(Foo, method, autospec=True):
        getattr(Foo(), method)(5)

The only subtest that fails is foo. The other two pass, even though they're clearly being called incorrectly.

If you prefer not to use pytest to demo/repro this:

with patch.object(Foo, "foo", autospec=True):
    try:
        Foo().foo(5)
    except TypeError:
        print("Correctly raises on foo")
    else:
        print("Incorrectly does not raise with foo")

with patch.object(Foo, "bar", autospec=True):
    try:
        Foo().bar(5)
    except TypeError:
        print("Correctly raises on bar")
    else:
        print("Incorrectly does not raise with bar")

with patch.object(Foo, "baz", autospec=True):
    try:
        Foo().baz(5)
    except TypeError:
        print("Correctly raises on baz")
    else:
        print("Incorrectly does not raise with baz")

This has output:

Correctly raises on foo
Incorrectly does not raise with bar
Incorrectly does not raise with baz

Your environment

• CPython versions tested on: 3.10, 3.11
• Operating system and architecture: macOS 12.6 with Apple M1 chip

Linked PRs

• gh-102978: Fix mock.patch function signatures for class and staticmethod decorators #103228
• [3.11] gh-102978: Fix mock.patch function signatures for class and staticmethod decorators (GH-103228) #103499

Activity

1. rileyjohngibbs

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Mar 23, 2023
2. arhadthedev

   added

   stdlibStandard Library Python modules in the Lib/ directoryStandard Library Python modules in the Lib/ directory

   on Apr 1, 2023
3. tomasr8 commented on Apr 3, 2023

   

   tomasr8

   on Apr 3, 2023

   Member

   More actions

   Looks like the signature is not set for @classmethod and @staticmethod. Adding a special case for them and using __func__ to get the correct signature I was able to get it to work. I'll see if I can contribute a PR that fixes this.

   Reacted by Riley Gibbs
4. cjw296

   added a commit that references this issue on Apr 13, 2023

   Merge branch 'main' into pythongh-102978

   1ec730f
5. cjw296

   closed this as completedon Apr 13, 2023
6. arhadthedev commented on Apr 13, 2023

   

   arhadthedev

   on Apr 13, 2023

   Member

   More actions

   @cjw296 Can this issue be considered completed? The child PR gh-103228 is neither merged nor backported yet.
7. miss-islington

   added a commit that references this issue on Apr 13, 2023

   pythongh-102978: Fix mock.patch function signatures for class and sta…

   64e3218
8. cjw296

   added a commit that references this issue on Apr 13, 2023

   gh-102978: Fix mock.patch function signatures for class and staticmet…

   59e0de4
9. carljm

   added a commit that references this issue on Apr 13, 2023

   Merge branch 'main' into superopt

   9384106
10. aisk

    added a commit that references this issue on Apr 18, 2023

    pythongh-102978: Fix mock.patch function signatures for class and sta…

    b00ae99
11. ambv

    added a commit that references this issue on May 22, 2023

    [3.11] gh-102978: Fix mock.patch function signatures for class and st…

    e95ca78
12. jscarfo11

    added 2 commits that reference this issue on Jan 13, 2025

    Fix 'raise_input_error' inline with the bugfix in python/cpython#102978

    c11feab

    Fix 'raise_input_error' inline with the bugfix in python/cpython#102978

    c7b2518
13. jhcole

    added 2 commits that reference this issue on Jan 22, 2025

    Fix 'raise_input_error' inline with the bugfix in python/cpython#102978

    cb17971

    Fix 'raise_input_error' inline with the bugfix in python/cpython#102978…

    956735b

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