Poetry installation fails. Windows 10, python39

• I am on the latest Poetry version.
• I have searched the issues of this repo and believe that this is not a duplicate.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: Windows 10 Education edition
• Poetry version: 1.1.4
• Link of a [Gist] with the contents of your pyproject.toml file: N/A
• Python version: 3.9

Issue

Poetry install fails on windows 10, both recommended installation (powershell) and Pip installation fail. Both methods have been tried in user and admin powershell consoles. My $PATH is correct.

PS C:\Users\me\workspace> (Invoke-WebRequest -Uri https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py -UseBasicParsing).Content | python -
Retrieving Poetry metadata

Welcome to Poetry!
... ... ... omitted
Installing version: 1.1.4
  - Downloading poetry-1.1.4-win32.tar.gz (38.82MB)
Traceback (most recent call last):
  File "<stdin>", line 1086, in <module>
  File "<stdin>", line 1082, in main
  File "<stdin>", line 362, in run
  File "<stdin>", line 529, in install
  File "<stdin>", line 676, in make_bin
  File "<stdin>", line 665, in _which_python
RuntimeError: No python executable found in shell environment. Tried: ['python', 'python3', 'py.exe -3', 'py.exe -2']
PS C:\Users\me\workspace> python --version
Python 3.9.0

PS C:\Users\me\workspace> pip install poetry --no-cache
... ... ... omitted
Installing collected packages: tomlkit, pylev, pastel, clikit, cleo, msgpack, lockfile, cachecontrol, poetry-core, cachy, filelock, appdirs, distlib, virtualenv, shellingham, webencodings, html5lib, pkginfo, poetry
    Running setup.py install for msgpack ... done
  WARNING: Failed to write executable - trying to use .deleteme logic
ERROR: Could not install packages due to an EnvironmentError: [WinError 2] The system cannot find the file specified: 'c:\\python39\\Scripts\\doesitcache.exe' -> 'c:\\python39\\Scripts\\doesitcache.exe.deleteme'

The powershell installation method tells me that it is unable to find my python executable, but it is certainly in my global PATH. Using the Pip installation method will result in it being unable to find an exe in “python39/scripts”. Running the pip installation again it tells me it can’t find a different exe before installation terminates. Indeed, these executables are not in that directory.

These installation methods will place a .poetry directory skeleton in my home, but will not place an executable for poetry in .poetry/bin

[eapetitfils]

I fixed the issue properly on my side, this was not a poetry problem, but rather an old installation of Anaconda not properly cleaned up.

Basically, whenever I was starting a command prompt in Windows, there was a message The system cannot find the path specified.. I was not alarmed as everything else was working. However, it does change the exit status to 1 instead of 0 when calling something with subprocess if using shell=True. You can reproduce the same error directly in the command prompt by doing:

cmd.exe /c "python --version"
echo %errorlevel%

The way I fixed it is described on StackOverflow: Open regedit.exe, navigate to Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Command Processor and make sure the value of the Autorun key exists. If not, clear the value. In my case, I had an entry for an Anaconda batch file that did not exist anymore.

While this error is not related to Poetry, maybe it would be interested to document it if the root cause is similar for other people.

[neersighted]

python-poetry/install.python-poetry.org#46