pipe connection error when using pytest-django and pytest-xdist

[piotr-kubiak]

Type: Bug

Behaviour

I have the following setup:
pyproject.toml:

[tool.poetry]
name = "django-vscode-pytest"
version = "0.1.0"
description = ""
authors = "Piotr Kubiak"
readme = "README.md"

[build-system]
requires = ["poetry-core"]
build-backend = "poetry.core.masonry.api"

[tool.poetry.dependencies]
python = "^3.11"
pytest = "^8.3.2"
pytest-xdist = "^3.6.1"
pytest-django = "^4.9.0"

test_Foo.py:

import pytest

@pytest.mark.django_db
def test_pass():
    assert True

I have also enabled the pythonTestAdapter experiment.
When I run this test (using the Testing panel), I get the result:

Received JSON data in run script
Running pytest with args: ['-p', 'vscode_pytest', '--rootdir=h:\\python\\django-vscode-pytest', 'h:\\python\\django-vscode-pytest\\test_Foo.py::test_pass']
============================= test session starts =============================
platform win32 -- Python 3.11.7, pytest-8.3.2, pluggy-1.5.0
rootdir: h:\python\django-vscode-pytest
configfile: pyproject.toml
plugins: django-4.9.0, xdist-3.6.1
collected 1 item

test_Foo.py s                                                            [100%]

============================= 1 skipped in 0.03s ==============================
Finished running tests!

The test is skipped (that is expected, I removed Django to create minimal example, and pytest-django skips tests that require Django).
Next, I add the -n 4 option to pytest:

[tool.pytest.ini_options]
addopts = [
    "-n 4",
]

Now, when I run the test exactly as before, the test fails unexpetedly with error vscode_pytest.VSCodePytestError: Error attempting to connect to extension named pipe.

Steps to reproduce:

As above.

Diagnostic data

Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)

Received JSON data in run script
Running pytest with args: ['-p', 'vscode_pytest', '--rootdir=h:\\python\\django-vscode-pytest', 'h:\\python\\django-vscode-pytest\\test_Foo.py::test_pass']
============================= test session starts =============================
platform win32 -- Python 3.11.7, pytest-8.3.2, pluggy-1.5.0
rootdir: h:\python\django-vscode-pytest
configfile: pyproject.toml
plugins: django-4.9.0, xdist-3.6.1
created: 4/4 workers
4 workers [1 item]

s                                                                        [100%]Error attempting to connect to extension named pipe \\.\pipe\python-test-results-475b03408672b927dda0-sock[vscode-pytest]: [Errno 2] No such file or directory: '\\\\.\\pipe\\python-test-results-475b03408672b927dda0-sock'
If you are on a Windows machine, this error may be occurring if any of your tests clear environment variables as they are required to communicate with the extension. Please reference https://docs.pytest.org/en/stable/how-to/monkeypatch.html#monkeypatching-environment-variablesfor the correct way to clear environment variables during testing.

Traceback (most recent call last):
  File "c:\Users\Piotr\.vscode\extensions\ms-python.python-2024.12.2-win32-x64\python_files\vscode_pytest\__init__.py", line 857, in send_post_request
    __writer.connect()
  File "c:\Users\Piotr\.vscode\extensions\ms-python.python-2024.12.2-win32-x64\python_files\testing_tools\socket_manager.py", line 24, in connect
    self._writer = open(self.name, "w", encoding="utf-8")  # noqa: SIM115, PTH123
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: '\\\\.\\pipe\\python-test-results-475b03408672b927dda0-sock'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "c:\Users\Piotr\.vscode\extensions\ms-python.python-2024.12.2-win32-x64\python_files\vscode_pytest\run_pytest_script.py", line 73, in <module>
    pytest.main(arg_array)
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\_pytest\config\__init__.py", line 175, in main
    ret: ExitCode | int = config.hook.pytest_cmdline_main(config=config)
                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\pluggy\_hooks.py", line 513, in __call__
    return self._hookexec(self.name, self._hookimpls.copy(), kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\pluggy\_manager.py", line 120, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\pluggy\_callers.py", line 139, in _multicall
    raise exception.with_traceback(exception.__traceback__)
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\pluggy\_callers.py", line 103, in _multicall
    res = hook_impl.function(*args)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\_pytest\main.py", line 330, in pytest_cmdline_main
    return wrap_session(config, _main)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\_pytest\main.py", line 318, in wrap_session
    config.hook.pytest_sessionfinish(
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\pluggy\_hooks.py", line 513, in __call__
    return self._hookexec(self.name, self._hookimpls.copy(), kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\pluggy\_manager.py", line 120, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\pluggy\_callers.py", line 139, in _multicall
    raise exception.with_traceback(exception.__traceback__)
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\pluggy\_callers.py", line 122, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\_pytest\logging.py", line 870, in pytest_sessionfinish
    return (yield)
            ^^^^^
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\pluggy\_callers.py", line 122, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\_pytest\terminal.py", line 893, in pytest_sessionfinish
    result = yield
             ^^^^^
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\pluggy\_callers.py", line 122, in _multicall
    teardown.throw(exception)  # type: ignore[union-attr]
    ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\_pytest\warnings.py", line 141, in pytest_sessionfinish
    return (yield)
            ^^^^^
  File "h:\python\django-vscode-pytest\.venv\Lib\site-packages\pluggy\_callers.py", line 103, in _multicall
    res = hook_impl.function(*args)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\Piotr\.vscode\extensions\ms-python.python-2024.12.2-win32-x64\python_files\vscode_pytest\__init__.py", line 425, in pytest_sessionfinish
    send_post_request(payload)
  File "c:\Users\Piotr\.vscode\extensions\ms-python.python-2024.12.2-win32-x64\python_files\vscode_pytest\__init__.py", line 868, in send_post_request
    raise VSCodePytestError(error_msg) from error
vscode_pytest.VSCodePytestError: Error attempting to connect to extension named pipe \\.\pipe\python-test-results-475b03408672b927dda0-sock[vscode-pytest]: [Errno 2] No such file or directory: '\\\\.\\pipe\\python-test-results-475b03408672b927dda0-sock'
Finished running tests!

Extension version: 2024.12.2
VS Code version: Code 1.92.2 (fee1edb8d6d72a0ddff41e5f71a671c23ed924b9, 2024-08-14T17:29:30.058Z)
OS version: Windows_NT x64 10.0.22631
Modes:

• Python version (& distribution if applicable, e.g. Anaconda): 3.11.7
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Poetry
• Value of the python.languageServer setting: Default

User Settings

languageServer: "Pylance"

testing
• pytestEnabled: true

experiments
• optInto: ["pythonTestAdapter"]

Installed Extensions

Extension Name	Extension Id	Version
JavaScript Debugger	ms-vscode.js-debug	1.92.0
JavaScript Debugger Companion Extension	ms-vscode.js-debug-companion	1.1.3
Pylance	ms-python.vscode-pylance	2024.8.2
Python	ms-python.python	2024.12.3
Python Debugger	ms-python.debugpy	2024.10.0
Table Visualizer for JavaScript Profiles	ms-vscode.vscode-js-profile-table	1.0.9

[eleanorjboyd]

i will give this a try myself - I am not sure if the problem is multiple connections coming from the multiple runners or an ongoing issue we have seen with named pipes that we are switching off of shortly. I will let you know, thanks!

[github-actions]

Because we have not heard back with the information we requested, we are closing this issue for now. If you are able to provide the info later on, then we will be happy to re-open this issue to pick up where we left off.

Happy Coding!

[piotr-kubiak]

@karthiknadig @eleanorjboyd
Why this issue was closed?
I am not aware of any request for more information.

[karthiknadig]

This got accidentally closed due to info-needed flag. Reopening this.

[piotr-kubiak]

@karthiknadig If there is anything I can help with, I am more than happy to do so.