Annotations on "next generation" attrs classes not supported by autodoc

[jwodder]

Describe the bug

Version 20.1.0 of attrs introduced a new "next generation" API that uses attr.define and attr.field instead of attr.s and attr.ib. Unfortunately, autodoc does not treat this new API the same way as the old one; in particular, type annotations on attributes are not shown when using the new API.

How to Reproduce

$ git clone https://github.com/jwodder/sphinx-attrs-bug-20211018
$ cd sphinx-attrs-bug-20211018
$ tox -e docs
$ open docs/_build/html/index.html

Open docs/_build/html/index.html in a browser and observe that the @attr.s-using class has its attributes' type annotations shown, while the @attr.define-using one does not. Conversely, the @attr.define class has a constructor signature shown, while the @attr.s one does not.

Expected behavior

The rendered documentation for the @attr.s class and the @attr.define class should be the same, particularly in that the attributes of the @attr.define class should have their type annotations shown.

Your project

https://github.com/jwodder/sphinx-attrs-bug-20211018

Screenshots

OS

macOS

Python version

3.9.7

Sphinx version

4.2.0

Sphinx extensions

sphinx.ext.autodoc

Extra tools

No response

Additional context

No response

[tk0miya]

Note: It seems @attr.define uses __slots__ to generate attributes:

root@91e94d32e5d8:/sphinx-attrs-bug-20211018/docs# python
Python 3.9.7 (default, Sep  3 2021, 02:02:37)
[GCC 10.2.1 20210110] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sphinx_attrs
>>> sphinx_attrs.Foo.__slots__
('bar', 'baz', 'quux', '__weakref__')