Pyright hanging a vscode process when analyzing requests library

[microcoder]

Describe the bug
Pyright hanging a vscode process when openned at vscode the requests library

To Reproduce
Create a new python file and import the requests library:

import requests

Then click CTRL + Left mouse click to open the requests library. After then a vscode process hangup.

[erictraut]

Thanks for the bug report. Which version of the Pyright extension are you running? There was a bug in 1.0.15 that could explain this. It's fixed in 1.0.16. I'm not able to repro the problem with the latest version.

[microcoder]

@erictraut I am use last version of Pyright 1.0.16 and VS Code last version - 1.33.1

When i opening the requests:

Pyright uses 100% a core of CPU and do not stopped:

[erictraut]

Ah, I was opening the stub file, and you were opening the implementation file. I'm now able to repro the problem. I'll dig into it and work on a fix.

[microcoder]

@erictraut Thank You!

[erictraut]

The bug is triggered by code in the requests module that performs the following:

for v in vs
   if <condition>
      v = [v]

This causes pyright to infer the type of v to be either X or List[X]. As it analyzes the loop, it adds more variants (List[List[X]], List[List[List[X]]], etc.). This results in an infinite loop.

I've added a partial fix that prevents infinite recursion in this particular case, but I'd like to find a more general fix. I'm going to leave this bug open until I've fully fixed the problem.

[erictraut]

I've fixed the underlying root cause of the problem in 1.0.24