PyEnv + Poetry: Poetry does not use correct Python versions

• 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: macOS 12.01

• Poetry version: 1.1.13

Issue

I find it extremely challenging, i.e. impossible, to get poetry to use the correct Python version. I am using PyEnv to manage Python.

which python
/Users/XXX/.pyenv/shims/python

pyenv versions
  system
* 3.8.12 (set by /Users/XXX/projectA/.python-version)
  3.9.7

python -V
Python 3.8.12

BUT within projectA:

poetry shell

python -V
Python 3.10.2

Even though:

[tool.poetry]
name = "ABC"
version = "0.1.0"
description = ""
authors = ["XXX"]

[tool.poetry.dependencies]
python = "3.8.12"

[tool.poetry.dev-dependencies]

[build-system]
requires = ["poetry-core>=1.0.0"]
build-backend = "poetry.core.masonry.api"

I have zero clue what I am doing wrong. Reading a couple of online resources did not help my understanding much. However obvious this is for core users, it is extremely frustrating and counterintuitive for me.

How to set this up correctly?

See also:

• https://blog.karnwong.me/python-venv-management/
• https://lifesaver.codes/answer/poetry-using-the-wrong-python-version-not-related-to-pyenv-655

[finswimmer]

Creating a venv with the current active Python on poetry install had only ever worked, when Poetry was installed via the get-poetry.py script. This was a side effect of the fact, that Poetry itself runs then with currently active Python version.

When Poetry was installed in any other way (install-poetry.py, pip, pipx) it will use the Python that was used during the installation, because Poetry now runs in its own environment and have no idea about your current active Python.

One can point Poetry to a specific Python binary that should be used to create the venv, by running poetry env use /path/to/python once per project before the venv creation. In case of pyenv this can look like this:

pyenv shell 3.8.12
poetry env use python3.8
poetry install

You can not use python as an argument for poetry env use here, because its forwarded to the underlying virtualenv which understand it as the system python and not the currently activated python.

With the next alpha release there will be an option experimental option virtualenvs.prefer-active-python (See https://github.com/python-poetry/poetry/pull/4852). Setting this to true, one should be able to switch to the desired Python version by pyenv before the venv creation and Poetry will than pick it up - regardless of the installation method.

fin swimmer

[thoughtfuldata]

@finswimmer Your solution doesnt work with a windows computer. I am using pyenv-win and even when I successfully create a shell it still installs the previous python version. I am attempting to go from python 3.9.6 to 3.9.11

These are my steps:

1. pyenv shell 3.9.11
2. poetry env use python ( i do check that python points to the 3.9.11)
3. poetry install

poetry installs 3.9.6 instead of 3.9.11

I am using poetry version 1.1.12( I just realized I have an issue with updating to 1.1.13), Windows 11, Pyenv-win 2.64.11