Tests hang if subprocess spawned but not killed

[JamesHutchison]

Type: Bug

Behaviour

Expected vs. Actual

Expected:
When all tests complete, the test runner acts like everything is good (legacy behavior).

Actual:
When running tests, even if all tests complete, the test GUI will continue to show a spinner and block running new tests if a test leaves a process running.

Steps to reproduce:

1. Have a test spawn a subprocess, but don't kill it.
2. Alternatively, use pytest-hot-reloading, which is the library where I encountered this issue. It has the argument --daemon-start-if-needed which starts the pytest daemon automatically when running a test.

The library has a codespace already configured: https://github.com/JamesHutchison/pytest-hot-reloading

Diagnostic data

• Python version (& distribution if applicable, e.g. Anaconda): 3.10.12
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Poetry
• Value of the python.languageServer setting: Default

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

XXX

User Settings

languageServer: "Pylance"

testing
• pytestArgs: "<placeholder>"
• pytestEnabled: true

Extension version: 2023.20.0
VS Code version: Code 1.84.2 (1a5daa3a0231a0fbba4f14db7ec463cf99d7768e, 2023-11-09T10:51:52.184Z)
OS version: Windows_NT x64 10.0.19045
Modes:
Remote OS version: Linux x64 6.2.0-1016-azure
Remote OS version: Linux x64 6.2.0-1016-azure

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz (8 x 2808)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: enabled_on direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled
Load (avg)	undefined
Memory (System)	15.89GB (4.65GB free)
Process Argv	--crash-reporter-id ae591a24-d374-4309-8087-11db7f271645
Screen Reader	no
VM	0%

Item	Value
Remote	Codespaces: orange giggle
OS	Linux x64 6.2.0-1016-azure
CPUs	AMD EPYC 7763 64-Core Processor (2 x 3035)
Memory (System)	7.74GB (5.57GB free)
VM	0%

Item	Value
Remote	Codespaces: fluffy capybara
OS	Linux x64 6.2.0-1016-azure
CPUs	AMD EPYC 7763 64-Core Processor (2 x 3242)
Memory (System)	7.74GB (3.89GB free)
VM	0%

A/B Experiments

vsliv368cf:30146710
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pythonptprofiler:30281270
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bridge0708:30335490
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vsaa593:30376534
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py29gd2263:30899288
vsclangdf:30486550
c4g48928:30535728
dsvsc012cf:30540253
pynewext54:30695312
azure-dev_surveyone:30548225
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pythonfmttext:30731395
fixshowwlkth:30771522
showindicator:30805244
pythongtdpath:30769146
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pythonnosmt12:30797651
pythonidxpt:30866567
pythonnoceb:30805159
asynctok:30898717
dsvsc013:30795093
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pythontestfixt:30902429
pyreplss1:30897532
pythonmypyd1:30879173
pythoncet0:30885854
h48ei257:30885898
pythontbext0:30879054
accentitlementsc:30887149
dsvsc016:30899300
dsvsc017:30899301
dsvsc018:30899302
aa_t_chat:30882232

[JamesHutchison]

See also:
JamesHutchison/pytest-hot-reloading#50

[eleanorjboyd]

Thank you for the issue! I will investigate.

One question, if you kill the subprocess does the test runner complete or does this happen either way?

[JamesHutchison]

Running on a debian codespace, I have to kill all subprocesses to get it to complete.

[JamesHutchison]

LMK if creating a branch from which you could create a codespace to reproduce the issue would be helpful.