use python3 by default to install poetry

[jgirardet]

Python3 should be default.

nobody on linux may execute this whithout sudo due to permission.

[digitalresistor]

There is a PEP specific to this issue: https://www.python.org/dev/peps/pep-0394/ and it recommends that python continue to link to python2, whereas python3 should link to the latest version of Python 3 installed on a system.

This change will hurt users, whereas using python3 it will do the right thing most of the time.

[jgirardet]

Hello,
maybe @bertjwregeer i'm not sure to all understand you said.
My mind is : everyone is leaving python2 so poetry should recommand python3. maybe my PR is not the good way to do it.
Maybe I'm wrong but I believe that on every system where python3 is system standard, there are both python and python3.

[digitalresistor]

Ah, I misread the PR. Sorry!

[osteele]

This introduces two changes: python -> python3; and the introduction of sudo -H.

On my machine (macOS with homebrew-installed python@2 and python3), using this with just the python3 change had the desired affect: it created a python3 virtual environment such that both
poetry run which python and poetry run which python3 refer to a Python in the appropriatevirtualenv, and both poetry run python --version and poetry run python3 --version display Python 3.6.5.

So yay for that! (I'd been trying to figure out how to use Poetry for Python 3 development, and was surprised that putting python = ">=3.0" in pyproject.toml didn't work. This PR saved me.)

I suspect, based on prior experience with sudo and homebrew, that if I'd run it with the sudo, I would have mixed up some ownerships in /usr/local/ in a way that could cause trouble downstream.

Maybe the sudo -H part of this change can either simply be removed, or moved to a different PR since if it's necessary at all, its has different compatibility issues and may be solving a different issue.

[osteele]

The change from python -> python3 works for me. I'm skeptical of adding sudo -H, and didn't need it. I left a longer comment on the line change. (Also, thanks for doing this. Finding this PR got me unblocked on trying out Poetry.)

[sdispater]

While the change for python3 seems good to me, I am not comfortable recommending sudo. Generally, I don't think it's a good idea to install tools like poetry for the root user.

[jgirardet]

ok but there still is a problem with the recommanded way to install poetry :
curl -sSL https://raw.githubusercontent.com/sdispater/poetry/master/get-poetry.py | python3
will alway fail on a standard linux distro due to permission :

jimmy@jimmyMint ~ $ curl -sSL https://raw.githubusercontent.com/sdispater/poetry/master/get-poetry.py | python3
Retrieving metadata

Installing version: 0.10.3
  - Getting dependencies
  - Vendorizing dependencies
  - Installing poetry
An error has occured: Command '('/usr/bin/python3', '-m', 'pip', 'install', '--upgrade', '--no-deps', '/tmp/poetry-installer-rr8vh6e7/poetry-0.10.3-py2.py3-none-any.whl')' returned non-zero exit status 1
Processing /tmp/poetry-installer-rr8vh6e7/poetry-0.10.3-py2.py3-none-any.whl
Installing collected packages: poetry
Could not install packages due to an EnvironmentError: [Errno 13] Permission non accordée: '/usr/local/lib/python3.5/dist-packages/__pycache__/toml.cpython-35.pyc'
Consider using the `--user` option or check the permissions.

[cauebs]

I agree with @sdispater and personally prefer the solution proposed by #146

[cauebs]

Is there a strong enough reason to recommend Python 3 explicitly? Don't get me wrong, I'm 100% pro-Python3, but Poetry supports 2.7 just as well.

[jgirardet]

actually I don't know if this PR is a good thing. it stays complicated to install even with the --user of #146

@sdispater why not just use pipsi. it works very good with poetry and install is only pipsi install poetry and thats it.

[cauebs]

What is the problem in installing with --user?

For me, if poetry is installed through pipsi, it doesn't work properly. Also, I personally think poetry should provide pipsi's functionality, as suggested in #149.

[jgirardet]

I just think that installing an app via a script is something painfull.
What doesn't work by you with pipsi ?

[cauebs]

Let's assume that I installed poetry through pipsi. If I create a new project and let poetry create the virtualenv, pip is not linked in .venv/bin and every install will fail with "permission denied" because system-wide pip will be used.

(this was reported in #169, but back then I was really confused, hahah)

[jgirardet]

you are right. I did not see it because I only use poetry with pyenv.
But not sure is it pipsi's fault. maybe poetry which should use the pip of the created virtualenv.

[cauebs]

That's the thing: the created virtualenv has no pip.

[sdispater]

Closing since the new installer is now more flexible.

[github-actions]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.