"Arguments missing" for optional arguments

[onnoeberhard]

I noticed that when I use a function with optional arguments I get an error message for "missing arguments". In this case, I was using the subplots function from the matplotlib.pyplot module. The actual error message was: Arguments missing for parameters "nrows", "ncols".

The function signature (https://matplotlib.org/_modules/matplotlib/pyplot.html#subplots) defines default arguments for these parameters. However, it looks like the pyplot.pyi file contains only def subplots(nrows: int, ncols: int, ....

Environment data

• Language Server version: 2020.6.1
• OS and version: Windows (10.0.17763 Build 17763)
• Python version (& distribution if applicable, e.g. Anaconda): Anaconda Python 3.7.7

Expected behaviour

(no error)

Actual behaviour

(error)

[PrateekArya]

I got the same for using plt.hist() without "bins". Error message: Argument missing for parameter "bins"

[erictraut]

It sounds like your type stub file (pyplot.pyi) contains a bug. Where did you get that stub? I don't see it included in the matplotlib package, nor do I see it in typeshed. In any case, the correct fix here is to fix the bug in the type stub file.

[onnoeberhard]

The pyplot.pyi file is located here: ~/.vscode/extensions/ms-python.vscode-pylance-2020.6.1/server/bundled-stubs/matplotlib/pyplot.pyi. I don't know where it came from.

[PrateekArya]

I see the same issue with my type stub file.

Should I just modify this here?

[jakebailey]

You can modify this in the bundle if you wish, but I expect to fix this.

[jakebailey]

This issue has been fixed in version 2020.7.0, which we've just released. You can find the changelog here: https://github.com/microsoft/pylance-release/blob/master/CHANGELOG.md#202070-9-july-2020

[netanelbz123]

Same issue with ImageGrab.grab() from PIL

[jakebailey]

Can you file a new issue? That's not related to this old closed issue, and is a bug with a bundled stub we ship.