TypeError: Cannot read property 'replace' of undefined when starting LS on Arch

Environment data

• VS Code version: 1.30.0
• Extension version (available under the Extensions sidebar): 2018.12.0
• OS and version: Arch Linux
• Python version (& distribution if applicable, e.g. Anaconda): 3.7.1
• Type of virtual environment used (N/A | venv | virtualenv | conda | …): N/A
• Relevant/affected Python packages and their versions: N/A

Expected behavior

Python extension loads with the language server running.

Actual behavior

The extension never finishes loading (“Python extension loading…” forever), and instead throws an exception from the code added in 66f8a27.

Steps to reproduce:

1. Start the extension with LS enabled on Arch.

Logs

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

Nothing is output.

Output from Console under the Developer Tools panel (toggle Developer Tools on under Help)

With the source map enabled:

  ERR Cannot read property 'replace' of undefined: TypeError: Cannot read property 'replace' of undefined
    at Object.SemVer [as parseVersion] (/home/jake/.vscode/extensions/ms-python.python-2018.12.0/src/client/common/utils/version.ts:12:1)
    at parseVersion (/home/jake/.vscode/extensions/ms-python.python-2018.12.0/src/client/common/platform/platformService.ts:142:1)
    at cb (/home/jake/.vscode/extensions/ms-python.python-2018.12.0/node_modules/getos/index.js:66:1)
    at cb (/home/jake/.vscode/extensions/ms-python.python-2018.12.0/node_modules/getos/index.js:125:51)
    at customLogic (/home/jake/.vscode/extensions/ms-python.python-2018.12.0/node_modules/getos/index.js:63:1)
    at FSReqWrap.readFileAfterClose [as oncomplete] (fs.js:511:3)

[jakebailey]

I’m really confused as to what you’re asking me for that’s different than what I provided. The stack trace I am describing is in my original issue. This is not some sort of big pop up from the editor. Pasted again:

  ERR Cannot read property 'replace' of undefined: TypeError: Cannot read property 'replace' of undefined
    at Object.SemVer [as parseVersion] (/home/jake/.vscode/extensions/ms-python.python-2018.12.0/src/client/common/utils/version.ts:12:1)
    at parseVersion (/home/jake/.vscode/extensions/ms-python.python-2018.12.0/src/client/common/platform/platformService.ts:142:1)
    at cb (/home/jake/.vscode/extensions/ms-python.python-2018.12.0/node_modules/getos/index.js:66:1)
    at cb (/home/jake/.vscode/extensions/ms-python.python-2018.12.0/node_modules/getos/index.js:125:51)
    at customLogic (/home/jake/.vscode/extensions/ms-python.python-2018.12.0/node_modules/getos/index.js:63:1)
    at FSReqWrap.readFileAfterClose [as oncomplete] (fs.js:511:3)

I can run my script by clicking the “play” button just fine, which tells me that an exception gets thrown when trying to start the LS, the future that indicates that the LS has started doesn’t complete, and the “extension loading” message doesn’t disappear.

[matejcik]

I’m seeing the same thing, commenting to clarify that this only happens when Jedi is disabled, i.e., when using Microsoft Python Language server. Jedi server loads fine. The same problem happens whether the LS is installed (by previous version of the python extension) or not.

(sorry for the noise if “LS” means the Microsoft language server by default)

My OS is Linux Mint 19 otherwise same version info, this doesn’t seem to depend on Python version (affects multiple 3.x environments with or without virtualenvs)