Fix support for folders in python.pythonPath setting

[meakbiyik]

Environment data

• VS Code version: 1.54.3
• Extension version (available under the Extensions sidebar): v2021.3.680753044
• OS and version: Windows 10.0.19041
• Python version (& distribution if applicable, e.g. Anaconda): 3.8.6
• Type of virtual environment used (N/A | venv | virtualenv | conda | ...): venv (via poetry)
• Value of the python.languageServer setting: Pylance

Expected behaviour

For "python.pythonPath": "${workspaceFolder}/.venv" workspace setting, extension is expected to find the virtualenv in the given directory.

Actual behaviour

The extension is unable to find the virtual env with the latest update (rolling back to the previous version works fine).

Steps to reproduce:

1. Create a virtualenv in the workspace possibly using poetry, and point to the workspace with ${workspaceFolder}/{workspace_name}

IMPORTANT NOTE: ".venv\\Scripts\\python.exe" works fine, but "${workspaceFolder}\\.venv", "${workspaceFolder}/.venv" does not. All of them works in the previous version.

Possibly related to #15781 but I do not have the error described in that issue in the output below.

Logs

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

User belongs to experiment group 'pythonaa'
User belongs to experiment group 'pythonJoinMailingListVar2'
User belongs to experiment group 'pythonJediLSP'
User belongs to experiment group 'pythonSendEntireLineToREPL'
User belongs to experiment group 'pythonNotDisplayLinterPrompt'
User belongs to experiment group 'pythonDiscoveryModuleWithoutWatcher'
User belongs to experiment group 'pythonFindInterpreter'
User belongs to experiment group 'ShowExtensionSurveyPrompt - enabled'
User belongs to experiment group 'CollectLSRequestTiming - control'
> c:\Users\erena\OneDrive\Desktop\SNLab\soccerbars/.venv c:\Users\erena\.vscode\extensions\ms-python.python-2021.3.680753044\pythonFiles\pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> c:\Users\erena\OneDrive\Desktop\SNLab\soccerbars/.venv c:\Users\erena\.vscode\extensions\ms-python.python-2021.3.680753044\pythonFiles\pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> c:\Users\erena\OneDrive\Desktop\SNLab\soccerbars/.venv c:\Users\erena\.vscode\extensions\ms-python.python-2021.3.680753044\pythonFiles\pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> c:\Users\erena\OneDrive\Desktop\SNLab\soccerbars/.venv c:\Users\erena\.vscode\extensions\ms-python.python-2021.3.680753044\pythonFiles\pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
Starting Pylance language server.
> c:\Users\erena\OneDrive\Desktop\SNLab\soccerbars/.venv c:\Users\erena\.vscode\extensions\ms-python.python-2021.3.680753044\pythonFiles\pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> c:\Users\erena\OneDrive\Desktop\SNLab\soccerbars/.venv c:\Users\erena\.vscode\extensions\ms-python.python-2021.3.680753044\pythonFiles\pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> c:\Users\erena\OneDrive\Desktop\SNLab\soccerbars/.venv c:\Users\erena\.vscode\extensions\ms-python.python-2021.3.680753044\pythonFiles\pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> c:\Users\erena\OneDrive\Desktop\SNLab\soccerbars/.venv c:\Users\erena\.vscode\extensions\ms-python.python-2021.3.680753044\pythonFiles\pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> c:\Users\erena\OneDrive\Desktop\SNLab\soccerbars/.venv c:\Users\erena\.vscode\extensions\ms-python.python-2021.3.680753044\pythonFiles\pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> c:\Users\erena\OneDrive\Desktop\SNLab\soccerbars/.venv c:\Users\erena\.vscode\extensions\ms-python.python-2021.3.680753044\pythonFiles\pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
Error 2021-03-25 12:24:27: Diagnostic Code: InvalidPythonInterpreterDiagnostic, Message: No Python interpreter is selected. You need to select a Python interpreter to enable features such as IntelliSense, linting, and debugging.
Diagnostic Code: InvalidPythonInterpreterDiagnostic, Message: No Python interpreter is selected. You need to select a Python interpreter to enable features such as IntelliSense, linting, and debugging.

[Mills-2]

On MacOS downgrading from 1.54.3 to 1.54.2 did not work for me. When I select the interpreter path through vscode to be in my venv path pythonPath is instead changed to an Xcode path. This is very unexpected to me.

Edit: if you have this issue simply performing a restart seemed to clear this issue after the downgrade. I still have the unexpected behavior however.

[angelitoTalens]

From #15781

it seems the detection of interpreter happen in a different shell and not using my venv.
weird thing is I can run unittest without the python interpreter detected since my pythonPath is set. So that means the unittest runs on my venv

Workaround:
the detection seems to work only if I populate my {$workspaceFolder}/.env file with the required LD_LIBRARY_PATH

[karrtikr]

Thanks for the bug report! We just wanted to quickly acknowledge we received it and we will triage this as soon as we can.

[karrtikr]

@meakbiyik The bug was introduced with #15726, but we plan to move away from supporting interpreter paths that way now, python.pythonPath can now only point to the binary itself (python.exe/python). We have multiple reasons for that:

• Inferring the actual python path using just the environment folder name required us to search for python executables within the directory itself by guessing which of

  vscode-python/src/client/common/configSettings.ts

  Lines 732 to 741 in c91b414

  	'python',
  	'python4',
  	'python3.6',
  	'python3.5',
  	'python3',
  	'python2.7',
  	'python2',
  	'python3.7',
  	'python3.8',
  	'python3.9',

  
  could be, and then verify whether it's a valid executable, which is observed to cause high CPU loads.
• We're likely deprecating the setting itself due to reasons mentioned in Details on the A/B experiment removing python.pythonPath support #12313. So sharing settings that way won't be possible.

You can try to workaround this using #12313 (comment).

[karrtikr]

I can temporarily fix this with #15806, but do note that we eventually plan to remove the support with #12313 🙂