Cannot read property 'length' of undefined

[lukasz-karolewski]

VS Code version

1.63.1

Extension version

2021.12.1559732655

OS type

Windows

OS version

windows 11 fully updated, running wsl 2 on ubuntu 20.10, running remote container extension using python image

Python distribution

python.org

Python version

3.9.9

Language server

Pylance

Expected behaviour

ideally python extension doesn't crash, and it worked before

Actual behaviour

[renderer1] [error] Cannot read property 'length' of undefined: TypeError: Cannot read property 'length' of undefined
at /root/.vscode-server/extensions/ms-python.python-2021.12.1559732655/out/client/extension.js:67:257359
at p (/root/.vscode-server/extensions/ms-python.python-2021.12.1559732655/out/client/extension.js:67:262355)
at async z.provideCompletionItems (/root/.vscode-server/bin/fe719cd3e5825bf14e14182fddeb88ee8daf044f/out/vs/server/remoteExtensionHostProcess.js:95:101516)

Steps to reproduce

is triggered by code suggestions with any python code and then it crashes the extension.

in a new window, new file type from datetime import and trigger code suggestion, no suggestions are show and extension is crashed

Also found this microsoft/vscode#110467 but i don't have two versions installed at the same time, and I've checked inside the container too.

Logs

[Info - 7:21:53 AM] Pylance language server 2021.12.2 (pyright 211ebe44) starting
[Info - 7:21:53 AM] Server root directory: /root/.vscode-server/extensions/ms-python.vscode-pylance-2021.12.2/dist
[Info - 7:21:53 AM] No configuration file found.
[Info - 7:21:53 AM] No pyproject.toml file found.
[Info - 7:21:53 AM] Setting pythonPath for service "workspace": "/usr/local/bin/python"
[Warn - 7:21:53 AM] stubPath /workspace/typings is not a valid directory.
[Info - 7:21:53 AM] Assuming Python version 3.9
[Info - 7:21:53 AM] Assuming Python platform Linux
[Warn - 7:21:53 AM] Exception received when installing file system watcher: TypeError [ERR_FEATURE_UNAVAILABLE_ON_PLATFORM]: The feature watch recursively is unavailable on the current platform, which is being used to run Node.js
[Warn - 7:21:53 AM] Exception received when installing file system watcher: TypeError [ERR_FEATURE_UNAVAILABLE_ON_PLATFORM]: The feature watch recursively is unavailable on the current platform, which is being used to run Node.js
[Warn - 7:21:53 AM] Exception received when installing file system watcher: TypeError [ERR_FEATURE_UNAVAILABLE_ON_PLATFORM]: The feature watch recursively is unavailable on the current platform, which is being used to run Node.js
[Info - 7:21:53 AM] Searching for source files
[Info - 7:21:53 AM] Found 220 source files
[Info - 7:21:53 AM] Background analysis(1) root directory: /root/.vscode-server/extensions/ms-python.vscode-pylance-2021.12.2/dist
[Info - 7:21:53 AM] Background analysis(1) started

Code of Conduct

• I agree to follow this project's Code of Conduct

[kimadeline]

Hi @lukasz-karolewski, thank you for reaching out.

Which Python container image are you using?

ideally python extension doesn't crash, and it worked before

What is the last version of the Python extension where that was working (no crash)?

[alextkatch]

I'm seeing the same issue on a new clean install, with both stable and insiders builds.

VS Code version: 1.64.0-insider
Extension version: v2021.12.1559732655 (Python), v2021.12.2 (Pylance)
OS type: Windows 11
OS version: 10.0.22000.376
Python distribution: python.org
Python version: 3.10.1

Expected: extension to load successfully on a simple file
Actual:

Code suggestions don't work. Extension host logs contain:

[2021-12-16 21:40:25.290] [exthost] [error] [ms-python.python] provider FAILED
[2021-12-16 21:40:25.290] [exthost] [error] TypeError: Cannot read property 'length' of undefined
	at c:\Users\alext\.vscode-insiders\extensions\ms-python.python-2021.12.1559732655\out\client\extension.js:67:257359
	at p (c:\Users\alext\.vscode-insiders\extensions\ms-python.python-2021.12.1559732655\out\client\extension.js:67:262355)
	at async W.provideCompletionItems (c:\Users\alext\AppData\Local\Programs\Microsoft VS Code Insiders\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:95:101474)

Steps to repro:

• Remove all VS code files
• Install VS code
• Install Python extension
• Open simple python file, like print("hello")
• On a new line type path.

Logs:

Experiment 'pythonaacf' is active
Experiment 'pythonTensorboardExperiment' is active
Experiment 'PythonPyTorchProfiler' is active
Experiment 'pythonDeprecatePythonPath' is active
> conda info --json
> C:\Python310\python.exe ~\.vscode-insiders\extensions\ms-python.python-2021.12.1559732655\pythonFiles\interpreterInfo.py
> c:\code\python\crash-course\.venv\Scripts\python.exe ~\.vscode-insiders\extensions\ms-python.python-2021.12.1559732655\pythonFiles\interpreterInfo.py
> conda --version
Python interpreter path: .\.venv\Scripts\python.exe
> "c:/code/python/crash-course/.venv/Scripts/activate.bat && echo 'e8b39361-0157-4923-80e1-22d70d46dee6' && python c:/Users/alext/.vscode-insiders/extensions/ms-python.python-2021.12.1559732655/pythonFiles/printEnvVariables.py"
Starting Pylance language server.

[lukasz-karolewski]

@kimadeline i'm using python:3.10,but as Alex pointed out it happens on a new clean install on local files please see above comment

[lukasz-karolewski]

@kimadeline bug has been introduced in v2021.11.1422169775, v2021.10.1365161279 works as expected

[DonJayamanne]

@kimadeline I've submitted a PR for this #18211