Parent class's __init__ docstring shown when child has a class docstring

[Prunoideae]

Environment data

• Language Server version : 2021.3.1
• OS and version: Windows 10 Pro Insider Preview Build 21313
• Python version (& distribution if applicable, e.g. Anaconda): 3.9.1 64-bit

Expected behaviour

class foo():
    '''
    Hello
    '''

    def __init__(self) -> None:
        pass

foo()

In this case Hello should be displayed when cursor is hovered on foo().

Actual behaviour

The very first doc of __init__ is displayed, other than the Hello, if we add '''Hello''' in the __init__'s spec then it will be displayed. And if we remove the __init__ definition, the class's docstring will be displayed.

This may cause inconvenience when reviewing large code blocks with objects, since docstrings are not directly displayed, and the case is inevitable even in packages like pandas because most code will not add same, or independent docstring for __init__, and it's repetitive if such a docstring is required other than a class's own docstring.

[judej]

Will investigate showing the most appropriate docstring. Thanks for the report.

[jakebailey]

The next release changes our docstring code to ignore object's docs for classes that aren't object itself. That will fix the above example:

... but won't fix something like this:

class A:
    """Class doc for A"""
    def __init__(self):
        """__init__ doc for A"""

class B(A):
    """Class doc for B"""

B()

As we search down the __init__ chain first, finding A.__init__ and using its doc, when we should probably be using B.__doc__.

Fixing this is a much more involved change.

[jakebailey]

This also begs the question of whether or not the class doc is the most appropriate doc in the above example; the method doc may have useful information on how to call it that the class doc would effectively hide. I'm thinking this issue was really only reported due to the 2021.3.0 fixing #550/#877, and previously 2020.9.6 added support for the builtin's docstrings (including object's pesky docs).

Perhaps the "right" solution is to call this fixed and see if anyone believes we should be showing B's doc in the example above later.

help shows both docs, since it's just listing everything, so that's not a useful comparison.

Help on class B in module __main__:

class B(A)
 |  Class doc for B
 |
 |  Method resolution order:
 |      B
 |      A
 |      builtins.object
 |
 |  Methods inherited from A:
 |
 |  __init__(self)
 |      __init__ doc for A

[jakebailey]

Yeah, I'm going to call this fixed for now. It seems like it's more consistent to not offer this doc if a parent __init__ has one.

[jakebailey]

This issue has been fixed in version 2021.9.1, which we've just released. You can find the changelog here: https://github.com/microsoft/pylance-release/blob/main/CHANGELOG.md#202191-8-september-2021

[leinaxd]

EDIT: NO BUG. very tricky

This Bug isn't fixed yet. isn't it?
i've also try with pytorch nn.Module, same bug for the same reason

Excellent test case by the way!

Oh, sorry... i understand why... now

• B() is calling an __init__ function
• B is the class

So it makes sense linting to __init__ when B() is called instead of class B