poetry run raises FileNotFoundError without any more information (workaround found)

• 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: docker alpine:3.13
• Poetry version: 1.1.4
• Link of a Gist with the contents of your pyproject.toml file: vanilla project from poetry init with a main.py and the following scripts section:

[tool.poetry.scripts]
main = "main:main"

Issue

Using the following Dockerfile as base image on our build pipeline.

FROM alpine:3.13
RUN apk add --update --no-cache python3 python3-dev py3-pip py3-pandas py3-numpy-dev hdf5-dev
RUN pip install poetry
RUN poetry config virtualenvs.create false

poetry run main crashes with the following error:

/workdir # poetry init
/workdir # poetry run -vvv main

  FileNotFoundError

  [Errno 2] No such file or directory

  at /usr/lib/python3.8/os.py:601 in _execvpe
       597│         path_list = map(fsencode, path_list)
       598│     for dir in path_list:
       599│         fullname = path.join(dir, file)
       600│         try:
    →  601│             exec_func(fullname, *argrest)
       602│         except (FileNotFoundError, NotADirectoryError) as e:
       603│             last_exc = e
       604│         except OSError as e:
       605│             last_exc = e

Note that enabling or disabling virtualenvs.create has the same effect.

Long story short, I've been able to work around the issue and hope this might help others. Here is what did the trick:

/workdir # ln -s /usr/bin/python3 /usr/bin/python

It seems that poetry run is expecting python to be found in the PATH (https://github.com/python-poetry/poetry/blob/master/poetry/console/commands/run.py#L40) on contrary to poetry which is directly using python3:

/workdir # head -1 /usr/bin/poetry
#!/usr/bin/python3

Start with poetry/console/commands/run.py and reproduce the command in the Alpine 3.13 Docker environment described in the issue. Check how poetry run resolves the configured script when only python3 is available, and use the existing traceback and workaround to define the expected behavior or error message.