Test Results named pipe error: Maximum call stack size exceeded #25366
Description
Type: Bug
Behaviour
The results of the test run aren't rendered in the UI (pass/fail icons an test IDs), VSCode seems to briefly hang and then it seems like extensions are restarted (syntax highlighting disappears and then comes back). This error is found in the logs:
2025-08-07 14:20:29.861 [error] Test Results named pipe /var/folders/8b/15h_47_d0_b3fq29xjvzjzgm0000gn/T/python-test-results-5bd6f7564d7c758da59c error: RangeError: Maximum call stack size exceeded
at /Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:951278
at Object.forEach (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:107:6251)
at t.PythonResultResolver._resolveExecution (/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:951229)
at t.PythonResultResolver.resolveExecution (/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:950352)
at /Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:993090
at b.callback (/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:963870)
at Object.thunk (/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:2016459)
2025-08-07 14:20:32.361 [info] Test Result named pipe /var/folders/8b/15h_47_d0_b3fq29xjvzjzgm0000gn/T/python-test-results-5bd6f7564d7c758da59c cancelled
Steps to reproduce:
I've been selectively running a group of 5-6 tests by clicking on the test function name (it's parameterized) in the Test Explorer and then re-running the same set of tests by interacting with the most recent test run from the Test Results output panel.
Diagnostic data
Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)
2025-08-07 14:20:15.090 [info] > . ~/Documents/dev/datachat/dcquery/.venv/bin/activate && echo 'e8b39361-0157-4923-80e1-22d70d46dee6' && python ~/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/python_files/printEnvVariables.py
2025-08-07 14:20:15.091 [info] shell: bash
2025-08-07 14:20:15.167 [warning] Unknown command line option passed into args parser for tests '--verify-query'. Please report on https://github.com/Microsoft/vscode-python/issues/new
2025-08-07 14:20:15.167 [warning] Unknown command line option passed into args parser for tests '--force-regen'. Please report on https://github.com/Microsoft/vscode-python/issues/new
2025-08-07 14:20:15.167 [info] arg: --rootdir already exists in args, not adding.
2025-08-07 14:20:15.167 [info] Attempting to use temp directory for test ids file, file name: test-ids-ccfaccbca148d9c2dd65.txt
2025-08-07 14:20:15.168 [info] Environment variables set for pytest execution: PYTHONPATH=/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/python_files, TEST_RUN_PIPE=/var/folders/8b/15h_47_d0_b3fq29xjvzjzgm0000gn/T/python-test-results-5c31ea7fe20997a16542, RUN_TEST_IDS_PIPE=/var/folders/8b/15h_47_d0_b3fq29xjvzjzgm0000gn/T/test-ids-ccfaccbca148d9c2dd65.txt
2025-08-07 14:20:15.169 [info] Running pytest with arguments: /Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/python_files/vscode_pytest/run_pytest_script.py --runxfail --verify-query --force-regen --rootdir=/Users/tyler/Documents/dev/datachat/dcquery for workspace /Users/tyler/Documents/dev/datachat/dcquery
2025-08-07 14:20:15.169 [info] > ~/Documents/dev/datachat/dcquery/.venv/bin/python ~/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/python_files/vscode_pytest/run_pytest_script.py --runxfail --verify-query --force-regen --rootdir=~/Documents/dev/datachat/dcquery
2025-08-07 14:20:15.169 [info] cwd: ~/Documents/dev/datachat/dcquery
2025-08-07 14:20:18.244 [error] Test Results named pipe /var/folders/8b/15h_47_d0_b3fq29xjvzjzgm0000gn/T/python-test-results-5c31ea7fe20997a16542 error: RangeError: Maximum call stack size exceeded
at /Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:951278
at Object.forEach (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:107:6251)
at t.PythonResultResolver._resolveExecution (/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:951229)
at t.PythonResultResolver.resolveExecution (/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:950352)
at /Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:993090
at b.callback (/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:963870)
at Object.thunk (/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:2016459)
2025-08-07 14:20:19.007 [info] Test Result named pipe /var/folders/8b/15h_47_d0_b3fq29xjvzjzgm0000gn/T/python-test-results-5c31ea7fe20997a16542 cancelled
2025-08-07 14:20:24.195 [warning] Unknown command line option passed into args parser for tests '--verify-query'. Please report on https://github.com/Microsoft/vscode-python/issues/new
2025-08-07 14:20:24.195 [warning] Unknown command line option passed into args parser for tests '--force-regen'. Please report on https://github.com/Microsoft/vscode-python/issues/new
2025-08-07 14:20:24.195 [info] arg: --rootdir already exists in args, not adding.
2025-08-07 14:20:24.195 [info] Attempting to use temp directory for test ids file, file name: test-ids-727609ad531400dcc210.txt
2025-08-07 14:20:24.196 [info] Environment variables set for pytest execution: PYTHONPATH=/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/python_files, TEST_RUN_PIPE=/var/folders/8b/15h_47_d0_b3fq29xjvzjzgm0000gn/T/python-test-results-5bd6f7564d7c758da59c, RUN_TEST_IDS_PIPE=/var/folders/8b/15h_47_d0_b3fq29xjvzjzgm0000gn/T/test-ids-727609ad531400dcc210.txt
2025-08-07 14:20:24.196 [info] Running DEBUG pytest with arguments: --runxfail,--verify-query,--force-regen,--rootdir=/Users/tyler/Documents/dev/datachat/dcquery,--capture=no for workspace /Users/tyler/Documents/dev/datachat/dcquery
2025-08-07 14:20:24.196 [info] Using configuration in workspace
2025-08-07 14:20:29.861 [error] Test Results named pipe /var/folders/8b/15h_47_d0_b3fq29xjvzjzgm0000gn/T/python-test-results-5bd6f7564d7c758da59c error: RangeError: Maximum call stack size exceeded
at /Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:951278
at Object.forEach (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:107:6251)
at t.PythonResultResolver._resolveExecution (/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:951229)
at t.PythonResultResolver.resolveExecution (/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:950352)
at /Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:993090
at b.callback (/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:963870)
at Object.thunk (/Users/tyler/.vscode/extensions/ms-python.python-2025.10.1-darwin-arm64/out/client/extension.js:2:2016459)
2025-08-07 14:20:32.361 [info] Test Result named pipe /var/folders/8b/15h_47_d0_b3fq29xjvzjzgm0000gn/T/python-test-results-5bd6f7564d7c758da59c cancelled
Extension version: 2025.10.1
VS Code version: Code 1.103.0 (Universal) (e3550cfac4b63ca4eafca7b601f0d2885817fd1f, 2025-08-06T21:40:10.271Z)
OS version: Darwin arm64 24.5.0
Modes:
- Python version (& distribution if applicable, e.g. Anaconda): 3.13.4
- Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): System
- Value of the
python.languageServersetting: Pylance
User Settings
Multiroot scenario, following user settings may not apply:
envFile: "<placeholder>"
languageServer: "Pylance"
testing
• pytestArgs: "<placeholder>"
• autoTestDiscoverOnSavePattern: "<placeholder>"
Installed Extensions
| Extension Name | Extension Id | Version |
|---|---|---|
| better-comments | aar | 3.0.2 |
| Bookmarks | ale | 13.5.0 |
| code-spell-checker | str | 4.0.47 |
| copilot | Git | 1.350.0 |
| copilot-chat | Git | 0.30.0 |
| debugpy | ms- | 2025.10.0 |
| docker | doc | 0.14.0 |
| dotenv | mik | 1.0.1 |
| even-better-toml | tam | 0.21.2 |
| github-markdown-preview | bie | 0.3.0 |
| gitlens | eam | 17.3.3 |
| go | gol | 0.48.0 |
| ini-for-vscode | Dav | 0.0.4 |
| javascript-docstrings | Mas | 1.1.1 |
| js-debug | ms- | 1.102.0 |
| js-debug-companion | ms- | 1.1.3 |
| just | ske | 2.0.0 |
| markdown-checkbox | bie | 0.4.0 |
| markdown-emoji | bie | 0.3.1 |
| markdown-footnotes | bie | 0.1.1 |
| markdown-mermaid | bie | 1.28.0 |
| markdown-preview-github-styles | bie | 2.2.0 |
| markdown-yaml-preamble | bie | 0.1.0 |
| npm-intellisense | chr | 1.4.5 |
| postman-for-vscode | Pos | 1.15.0 |
| prettier-vscode | esb | 11.0.0 |
| python | ms- | 2025.10.1 |
| rainbow-csv | mec | 3.20.0 |
| ruff | cha | 2025.24.0 |
| scalene | Eme | 0.0.10 |
| shellcheck | tim | 0.38.2 |
| sqltools | mtx | 0.28.4 |
| sqltools-driver-mssql | mtx | 0.4.6 |
| sqltools-driver-mysql | mtx | 0.6.4 |
| sqltools-driver-pg | mtx | 0.5.5 |
| sqltools-driver-redshift | kj | 0.0.4 |
| vscode-commitizen | Kni | 1.1.0 |
| vscode-containers | ms- | 2.1.0 |
| vscode-eslint | dba | 3.0.16 |
| vscode-js-profile-flame | ms- | 1.0.9 |
| vscode-js-profile-table | ms- | 1.0.10 |
| vscode-kubernetes-tools | ms- | 1.3.25 |
| vscode-language-babel | mgm | 0.0.40 |
| vscode-markdownlint | Dav | 0.60.0 |
| vscode-nginx | wil | 0.7.2 |
| vscode-pull-request-github | Git | 0.114.3 |
| vscode-pylance | ms- | 2025.7.1 |
| vscode-python-envs | ms- | 1.2.0 |
| vscode-scss-formatter | sib | 3.0.0 |
| vscode-speech | ms- | 0.16.0 |
| vscode-yaml | red | 1.18.0 |
System Info
| Item | Value |
|---|---|
| CPUs | Apple M1 Max (10 x 2400) |
| GPU Status | 2d_canvas: enabled 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 skia_graphite: enabled_on trees_in_viz: disabled_off video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off |
| Load (avg) | 2, 3, 4 |
| Memory (System) | 32.00GB (0.08GB free) |
| Process Argv | --crash-reporter-id 9c8b74e5-efe2-4756-b68a-91b9fde0fa03 |
| Screen Reader | no |
| VM | 0% |
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