Pipenv not finding pyenv versions with PYENV_HOME set

[zymergen-luke]

Issue description

Previously we could use a version of python installed via pyenv simply by setting the PYENV_HOME environment variable.

I started noticing this morning that builds were failing because pipenv was using the wrong version:

export PYENV_ROOT="~/.pyenv"
export PIPENV_VENV_IN_PROJECT="1"
$ pipenv install --dev
Warning: Your Pipfile requires python_version 3.7.0, but you are using 2.7.12 (/data/j/w/d/.venv/bin/python).
  $ pipenv --rm and rebuilding the virtual environment may resolve the issue.
  $ pipenv check will surely fail.

It is then running inside python2 (and crashing as such).

The version is successfully installed and can be found using the shims.

$ ${PYENV_ROOT}/bin/pyenv versions
* system (set by /data/jenkins/.pyenv/version)
  2.7.12
  3.6.4
  3.7.0

$ PYENV_VERSION=3.7.0 ${PYENV_ROOT}/shims/python --version
Python 3.7.0

Expected result

Pipenv should find the version installed by pyenv without any additional environment parameters

Actual result

Pipenv did not find the pyenv installed with the PYENV_ROOT environment variable set.

We were able to work around the issue by adding pyenv to PATH explicitly:

$ PATH="${PYENV_ROOT}/bin:${PATH}" pipenv install --dev
Installing dependencies from Pipfile.lock (104e24)…
  🐍   ▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉ 46/46 — 00:00:31
To activate this project's virtualenv, run pipenv shell.
Alternatively, run a command inside the virtualenv with pipenv run.

This was not previously required, however, and the documentation still claims that PYENV_ROOT is all that is needed.

Steps to replicate

1. Start with a blank environment that does not have pyenv added to PATH (or any PYENV_* environment variables)
2. Set PYENV_ROOT: export PYENV_ROOT="~/.pyenv"
3. Install python via pyenv: ${PYENV_ROOT}/bin/pyenv update && ${PYENV_ROOT}/bin/pyenv install 3.7.0
4. Run pipenv install on a Pipfile containing a 3.7.0 requirements:

[requires]
python_version = "3.7.0"

Notice that it warns that 3.7.0 was not found and will use the system python instead.

---

$ pipenv --support
<details><summary>$ pipenv --support</summary>

Pipenv version: `'2018.10.13'`

Pipenv location: `'/usr/local/lib/python2.7/dist-packages/pipenv'`

Python location: `'/usr/bin/python'`

Python installations found:

Traceback (most recent call last):
  File "/usr/local/bin/pipenv", line 11, in <module>
    sys.exit(cli())
  File "/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py", line 1114, in invoke
    return Command.invoke(self, ctx)
  File "/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/decorators.py", line 64, in new_func
    return ctx.invoke(f, obj, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/pipenv/vendor/click/decorators.py", line 17, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/pipenv/cli/command.py", line 142, in cli
    get_pipenv_diagnostics()
  File "/usr/local/lib/python2.7/dist-packages/pipenv/help.py", line 33, in get_pipenv_diagnostics
    python_paths = finder.find_all_python_versions()
  File "/usr/local/lib/python2.7/dist-packages/pipenv/vendor/pythonfinder/pythonfinder.py", line 112, in find_all_python_versions
    major=major, minor=minor, patch=patch, pre=pre, dev=dev, arch=arch
  File "/usr/local/lib/python2.7/dist-packages/pipenv/vendor/pythonfinder/models/path.py", line 222, in find_all_python_versions
    return [c for c in sorted(path_filter, key=version_sort, reverse=True)]
AttributeError: 'list' object has no attribute 'as_python'

[j-martin]

I am also experiencing the same issue with:

pyenv 1.2.8
pipenv, version 2018.10.13
macOS Mojave

Specifying the version explicitly with pipenv solved my issue

pipenv install --python ~/.pyenv/versions/3.5.6/bin/python

[techalchemy]

This is fixed in master, closing for now

[zymergen-luke]

@techalchemy Is there a PR or commit we could reference?

[zou000]

I met a similar problem but then I found this FAQ which solved my problem.
https://pipenv.readthedocs.io/en/latest/diagnose/#pipenv-does-not-respect-pyenvs-global-and-local-python-versions