Bug report

Bug description:

fromdataclassesimportdataclassfromunittest.mockimportcreate_autospec@dataclassclassDescription:name:strmock=create_autospec(Description,instance=True)print(isinstance(mock,Description))

# 3.13.3True# 3.14.0b2False

Furthermore the resulting mock doesn't have attributes present on a dataclass instance, like__annotations__,__class__,__dataclass_fields__,__dataclass_params__.

print(dir(mock))print(dir(Description("Hello World"))

Likely related to#124429. /CC@sobolevn

CPython versions tested on:

3.14

Operating systems tested on:

macOS

Linked PRs

• gh-135368: Fix mocks on dataclass specs withinstance=True #135421
• [3.14] gh-135368: Fix mocks on dataclass specs withinstance=True (GH-135421) #135503