Using multiprocessing -> TypeError: Cannot read properties of null (reading 'testsuites')

[MalteBecker]

Environment data

• debugpy version: 1.8.1
• OS and version: Win10 22H2
• Python version (& distribution if applicable, e.g. Anaconda): 3.9.18, pytest 7.4.3
• Using VS Code or Visual Studio: VSCode

Actual behavior

I get the Error TypeError: Cannot read properties of null (reading 'testsuites') when using the debug option in the test explorer and using the multiprocessing module. If I just execute the test, I don´t get the error.

Expected behavior

No error

Steps to reproduce:

1. Use this script:

import time
from multiprocessing import Pool

VALUES = [1, 2, 3, 4]


def do_something(bla: int):
    time.sleep(bla)


def test_multi():
    with Pool() as pool:
        pool.map(do_something, VALUES)


def test_for():
    for val in VALUES:
        do_something(val)

2. Configure pytest to find the tests.
3. Debug the "multi" test with the test explorer
   => Get the error TypeError: Cannot read properties of null (reading 'testsuites') in the "TEST RESULTS" tab.

[int19h]

This sounds like a TypeScript exception, so I think this is coming from test explorer code. Could you file it on https://github.com/microsoft/vscode-python?

[MalteBecker]

This sounds like a TypeScript exception, so I think this is coming from test explorer code. Could you file it on https://github.com/microsoft/vscode-python?

Thank you. I created the same issue there: microsoft/vscode-python#23064

[gramster]

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