New submission from Micael Jarniac <mic...@jarniac.com>:
https://docs.python.org/3/library/dataclasses.html#post-init-processing https://github.com/python/cpython/blob/3.9/Doc/library/dataclasses.rst#post-init-processing In the example, a base class "Rectangle" is defined, and then a "Square" class inherits from it. On reading the example, it seems like the Square class is meant to be used like: >>> square = Square(5) Since the Square class seems to be supposed to be a "shortcut" to creating a Rectangle with equal sides. However, the Rectangle class has two required init arguments, and when Square inherits from it, those arguments are still required, so using Square like in the above example, with a single argument, results in an error: >>> square = Square(5) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: __init__() missing 2 required positional arguments: 'width' and 'side' To "properly" use the Square class, it'd need to be instantiated like so: >>> square = Square(0, 0, 5) >>> square Square(height=5, width=5, side=5) Which, in my opinion, is completely counter-intuitive, and basically invalidates this example. ---------- assignee: docs@python components: Documentation messages: 395427 nosy: MicaelJarniac, docs@python priority: normal severity: normal status: open title: Bad dataclass post-init example type: behavior versions: Python 3.8 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue44365> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
