Select pyenv environment based on folder .python-version file

[dan-blanchard]

Environment data

• VS Code version: 1.21.1
• Extension version (available under the Extensions sidebar): 2018.2.1
• OS and version: macOS 10.13.3
• Python version (& distribution if applicable, e.g. Anaconda): Python 3.6.4
• Type of virtual environment used (N/A | venv | virtualenv | conda | ...): pyenv
• Relevant/affected Python packages and their versions: pyenv 1.2.1

Actual behavior

You have to manually select the pyenv interpreter for each workspace folder.

Expected behavior

It should detect the workspace pyenv interpreter based on the .python-version file present in the workspace folder root.

For example, every folder I have added to my workspace has a .python-version file that pyenv creates when you run pyenv local NAME_OF_VENV in that folder. The file contains a single string which is the name of the folder/symlink in ~/.pyenv/versions/ that should be used.

[brettcannon]

https://github.com/pyenv/pyenv#choosing-the-python-version has the specification on how pyenv chooses an interpreter by default. I think detecting the file and using it as appropriate seems like a sensible enhancement (maybe even the file traversal to the parent directory, but not as sure on that one).

[neverfox]

@brettcannon I'm not sure if it's possible but you should be able to let pyenv do the heavy lifting if you use the shims it provides as the interpreter, as long as its run in a context (i.e. directory) aware way.