Provide a way to explicitly tell the extension to automatically pick interpreter from PATH

[jraygauthier]

Some context

Currently using nix to create versionable environments for my projects. I enter the environment (using nix-shell) and then launch code from inside this environment. The environment provides a python interpreter via the PATH environment variable. This python interpreter comes packed with all the python projects dependencies. The interpreter is located in the nix store: /nix/store/4qp2kldp8pn912gdsiawxkvyh6dajlpw-python3.5-python35-interpreter/bin/python. This path changes for any tiny change to the interpreter of its dependencies (including system dependencies of the python interpreter or any of the python dependencies which are also delivered by nix).

The problem

At some point in the past (before the extension being taken over by ms) specifying python.pythonPath = "python" was enough for nix env interpreter being picked by vscode. However, at some point it stopped working properly (selecting the python from the system or venv instead of PATH). After some search and experimentation, I discovered that specifying instead python.pythonPath": "${env:NIX_PYTHON_INTERPRETER}" was a workaround.

This is however a bit awkward and redundant as it forces me to define the NIX_PYTHON_INTERPRETER environment variable as part of the shellHook of each of my nix env.

Also, for most projects I work on, all developers use nix and as such we generally like to be explicit that for this particular project, we want vscode to automatically pick the python interpreter from PATH (as provided by the nix env). This is why we generally set ${env:NIX_PYTHON_INTERPRETER} in the project's .vscode/settings.json but would have instead preferred to only specify python.pythonPath = "python" or any other expression that tells vscode to take the interpreter from PATH.

As a sideline, if I understood well, I learn that this might no longer be possible to specify this settings as part of .vscode/settings.json nor workspace settings. See Queries about moving workspace pythonPath setting into VSCode storage · Issue #12313 · microsoft/vscode-python for some context.

Note that this issue is really about a way to reliable pick the interpreter from PATH and the possibility to be explicit about it and ideally that his can be specified on a per project basis, optionally version controlled.

[brettcannon]

Thank you for the suggestion! We have marked this issue as "needs decision" to make sure we have a conversation about your idea. We plan to leave this feature request open for at least a month to see how many 👍 votes the opening comment gets to help us make our decision.

[CatNofishing]

good suggestion

[luabud]

Thanks for the suggestion! We talked about it with the team and we have unfortunately decided we will not be moving forward with this idea. We think there isn't an enough widespread need for this to warrant the maintenance cost for the feature.

[simonrainerson]

Hello, at my workplace we are switching over to use nix for our development environments and we just discovered the same issue with using vscode. This feature would be very helpful so we can use different versions of python in different circumstances.