Support Python Launcher on Windows when using poetry env use and poetry env remove (#3520)

[sitd2813]

Pull Request Check List

Resolves: #issue-number-here

• Added tests for changed code.
• Updated documentation for changed code.

Fix #3520

I did not add any test because I'm not really familiar with PyTest and thus had no idea how to add Windows specific test. However, the code was built and tested on Windows 10 device and it proved to resolve #3520 without apparent errors.

EDIT

Added test to verify if EnvManager._execute_python_script works as expected.

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

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[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

[sitd2813]

Both tests currently failed due to ConnectionError. I have no idea why it occurred. It seems like there is an issue with the testing platform.

[Leonardofreua]

What do you think about creating a constant for the script "\"import sys; print('.'.join([str(s) for s in sys.version_info[:3]]))\""?

[sitd2813]

Thank you for reviewing my code. I added the constant for the script. Also, I made the execute_python_script a member function of EnvManager as it is only used inside it. It is now EnvManager._execute_python_script.

[Leonardofreua]

Great. Good catch.

[sitd2813]

Is there anything else I need to do? It seems that running more test require approval.

[Leonardofreua]

I think it needs more tests and one more reviewer.

[dalito]

As a fan of the launcher I have tested your PR with poetry-1.2.0a2 on Win10. It mostly works. 👍

Only when removing an env an error occurs. The env is removed nevertheless. The error is probably due to a "feature" in Win10. When you don't have python on path but enter "python", Win10 suggests to install Python from the Microsoft store. So testing for "python" gives an unexpected output. Maybe it is better to test for the presence of "pip"?

λ poetry env use python3.8
Creating virtualenv mared-NfQ5kqas-py3.8 in C:\Users\zzz\AppData\Local\pypoetry\Cache\virtualenvs
Using virtualenv: C:\Users\zzz\AppData\Local\pypoetry\Cache\virtualenvs\mared-NfQ5kqas-py3.8

λ poetry env remove python3.8

  CalledProcessError

  Command 'python -W ignore -' returned non-zero exit status 9009.

  at C:\dev\Python39\lib\subprocess.py:528 in run
       524│             # We don't call process.wait() as .__exit__ does that for us.
       525│             raise
       526│         retcode = process.poll()
       527│         if check and retcode:
    →  528│             raise CalledProcessError(retcode, process.args,
       529│                                      output=stdout, stderr=stderr)
       530│     return CompletedProcess(process.args, retcode, stdout, stderr)
       531│
       532│

The following error occurred when trying to handle this error:


  EnvCommandError

  Command python -W ignore - errored with the following return code 9009, and output:
  Python was not found but can be installed from the Microsoft Store: https://go.microsoft.com/fwlink?linkID=2082640input was : import sys

  if hasattr(sys, "real_prefix"):
      print(sys.real_prefix)
  elif hasattr(sys, "base_prefix"):
      print(sys.base_prefix)
  else:
      print(sys.prefix)


  at ~\_poetry\venv\lib\site-packages\poetry\utils\env.py:1285 in _run
      1281│                 output = subprocess.check_output(
      1282│                     cmd, stderr=subprocess.STDOUT, env=env, **kwargs
      1283│                 )
      1284│         except CalledProcessError as e:
    → 1285│             raise EnvCommandError(e, input=input_)
      1286│
      1287│         return decode(output)
      1288│
      1289│     def execute(self, bin: str, *args: str, **kwargs: Any) -> Optional[int]:

[sitd2813]

There are some issues that need discussions which are:

1. When I type poetry env use python3.9 or any similar command, should poetry prefer py -3.9 or python3.9 or python (3.9) given that all 3 commands exist in the system?
2. Due to how poetry detects the python executable in the system, py launcher detection will produce long unintuitive error messages.
3. As @dalito reported, it seems that Windows' python alias also causes problems.

I think a new issue elaborating the behavior should be created.

[neersighted]

The current consensus is that we should use pythonfinder instead of trying to write out this logic ourselves. Feel free to re-open this PR if you'd like to switch to that approach -- otherwise, @bmarroquin has expressed interest in PRing pythonfinder support.

[github-actions]

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