Poetry using the wrong Python version (not related to pyenv)

[zmitchell]

• I have searched the issues of this repo and believe that this is not a duplicate.
• I have searched the documentation and believe that my question is not covered.

Question

I'm having an issue adding a package to a project because poetry is picking up on the wrong Python version. I'm pretty confident that something has gone awry in my system, but I'm doing my best to salvage the situation and not have to go through the whole process of installing Raspbian from scratch on this Raspberry Pi. I installed poetry using the recommended method (curl ...). Can you point me in the right direction? As mentioned in the title, I'm not using pyenv. All of the relevant issues I found were related to pyenv, so I'm not really sure how to get poetry to use the correct Python.

Here are some terminal outputs to help you diagnose the issue:

pi@widget:temp_logger$ python --version
Python 3.5.3
pi@widget:temp_logger!$ sudo python --version
Python 2.7.13
pi@widget:temp_logger$ poetry --version
Poetry 0.12.9
pi@widget:temp_logger$ poetry debug:info

Poetry
======

 * Version: 0.12.9
 * Python:  2.7.13


Virtualenv
==========

 * Python:         2.7.13
 * Implementation: CPython
 * Path:           NA


System
======

 * Platform: linux2
 * OS:       posix
 * Python:   /usr


pi@widget:temp_logger$ poetry add adafruit-blinka

[RuntimeError]
The current Python version (2.7.13) is not supported by the project (^3.5)
Please activate a compatible Python version.

add [-D|--dev] [--git GIT] [--path PATH] [-E|--extras EXTRAS] [--optional] [--python PYTHON] [--platform PLATFORM] [--allow-prereleases] [--dry-run] [--] <name> (<name>)...

[sdispater]

As you can see in debug:info, Poetry picks up Python 2.7.13 and not Python 3.5.3. What is the output of which python? Does it point to your 2.7.13 Python or 3.5.3?

[zmitchell]

Ah, here we go. It turns out python was aliased to python3, and doing which python uncovered that. Now python --version returns 2.7.13, and which python returns /usr/bin/python. So how do I get poetry to use Python 3 instead?

[buriy]

@sdispater the issue is even worse.

Poetry starting with 0.12.5 stopped working with the python version from the virtualenv, only checks system version of Python.
Version 0.12.4 is the last version that worked propertly.

After this command $ sudo pip3 install poetry it shows:

$ poetry update
[RuntimeError]                                                
The current Python version (3.6.7) is not supported by the project (~2.7)  
Please activate a compatible Python version.                               

$ poetry debug:info

Poetry
======

 * Version: 0.12.9
 * Python:  3.6.7


Virtualenv
==========

 * Python:         2.7.15
 * Implementation: CPython
 * Path:           /Projects/myproject/.venv
 * Valid:          True


System
======

 * Platform: linux
 * OS:       posix
 * Python:   /usr

If you would install it with sudo pip2 install poetry, it will work with python 2.7 projects, but won't work with python 3.6 projects.
I don't use "source .venv/bin/activate" and I shouldn't be forced to.

[sdispater]

@buriy Commit 94304e9 should fix your issue.

It will land in the next bugfix release.

[buriy]

@sdispater Thanks, then these are different issues with the one from topic starter.
Sorry for hijacking thread.

[buriy]

@zmitchell Then, If I got it right, try reinstalling poetry. If installed with python2, it's bound to using python2 unless you use pyenv or virtualenv.

[zmitchell]

I reinstalled with Python 3 using curl ... | python3 and it still only picks up 2.7.

[jtbeach]

@zmitchell In 0.12.x, poetry is not bound to the interpreter version you curl the installer script through during installation -- so it doesn't matter which one you install it with with.

If python points to python2 and your project needs python3, you have 2 choices:

1. (preferable) Use pyenv and run pyenv local 3.7.0 or whatever your project wants in the root folder of your project. If you have your pyenv shims setup correctly in your shell startup files, python will now execute Python 3.7.0 whenever python runs from that folder or its subfolders, regardless of what python points to globally.

2. Manually create a virtualenv with Python 3 and activate it prior to running poetry commands. You can use direnv or similar to make that a little more automated, but I still prefer using pyenv -- once you get used to it, it's great

[buriy]

@jtbeach

2. Manually create a virtualenv with Python 3 and activate it prior to running poetry commands. You can use direnv or similar to make that a little more automated, but I still prefer using pyenv -- once you get used to it, it's great

Plese note that this option for the local .venv folder is broken in version 0.12.5 and will be fixed in version 0.12.10, which is not yet published (I rechecked it's not fixed in 0.12.9).

[sdispater]

@zmitchell For now, your best bet is to use pyenv (which is the easiest way to manager different Python versions if you are not on Windows) until #621 is implemented (work in progress here https://github.com/sdispater/poetry/tree/env-command)

[sdispater]

@buriy Release 0.12.10 is out! 

[buriy]

@sdispater thanks a lot!
Option 2 mentioned by @jtbeach works again.

[asodeur]

Not sure if this is the original issue or a new Windows related issue (seeing this on 0.12.10 and 1.0.0a1).

SystemEnv.run("python", ...) will always use the primary system interpreter on Windows even if poetry is running on another one not installed in a virtual env. This is because SystemEnv._bin("python") is looking for python.exe in SystemEnv._bin_dir which on Windows is <Python root>/Scripts, however the interpreter is there for virtual envs only. for standard Python installations the interpreter is <Python root>/python.exe.

Running poetry from inside a virtual env, ie option 2 above works fine.