Problem vendoring subprocess32 in Ubuntu

• 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).

• Ubuntu 16.04/18.04:

Issue

I’m building a Dockerfile and am seeing a RuntimeWarning after running any poetry command that works with the venv. Since I’m using poetry to run a web server (gunicorn), I’m worried that this could have a negative impact on app performance. I haven’t seen this before, so it appears to have been introduced recently?

The warning:

/root/.poetry/lib/poetry/_vendor/py2.7/subprocess32.py:149: RuntimeWarning: The _posixsubprocess module is not being used. Child process reliability may suffer if your program uses threads.
  "program uses threads.", RuntimeWarning)

I installed poetry using the get-poetry.py script, and have even updated to the latest version. Here is the Dockerfile that I’m using, and the relevant output:

FROM ubuntu:16.04
RUN apt-get update && apt-get install -y \
    software-properties-common \
    curl \
    htop \
    python \
    python-dev \
    wget
RUN curl -sSL https://raw.githubusercontent.com/sdispater/poetry/master/get-poetry.py | python
ENV PATH=$PATH:/root/.poetry/bin
RUN poetry self:update --preview
RUN poetry version

And the output for the final command…

$: poetry version
/root/.poetry/lib/poetry/_vendor/py2.7/subprocess32.py:149: RuntimeWarning: The _posixsubprocess module is not being used. Child process reliability may suffer if your program uses threads.
  "program uses threads.", RuntimeWarning)

[ImportError]
No module named pkg_resources

[marcelomendes]

I’m having same issue, Debian current, Python 3.7.4

Editing ~/.poetry/bin/poetry and changing “/usr/bin/env python” to “/usr/bin/env python3” fix it, but this will be probably overridden after next self:update

[camilonova]

Shouldn’t we use? #!/usr/bin/env python3

I don’t know if we should use a fallback version to python2 but seems reasonable to support python3 only.