sys.executable and sys.path are wrong when running virtualenv python in subprocess on macOS

[rdbisme]

When launching the virtualenv python bynary from a subprocess from the system binary, the environment in which the subprocess call is running looks wrong: e.g. it returns the system python binary as sys.executable.
If the virtualenv is created using venv, things work as expected.

On Linux the bug is not present.

Python Details

Python 3.7.6 (default, Dec 22 2019, 01:09:06)
[Clang 11.0.0 (clang-1100.0.33.12)] on darwin

OS details

10.15.3 (but I could also reproduce on 10.14)

If I do (using the system python): python -m venv $WORKON_HOME/test-venv and then:

$> which python
/opt/local/bin/python
$>python
>>> import subprocess
>>> subprocess.check_output('/Users/rubendibattista/.envs/test-venv/bin/python -c "import sys; print(sys.executable)"', shell=True)
b'/Users/rubendibattista/.envs/test-venv/bin/python\n'

On the other hand, if I create a virtual env using virtualenv:

$> virtualenv $WORKON_HOME/test-virtualenv
Using base prefix '/opt/local/Library/Frameworks/Python.framework/Versions/3.7'
New python executable in /Users/rubendibattista/.envs/test-virtualenv/bin/python3.7
Also creating executable in /Users/rubendibattista/.envs/test-virtualenv/bin/python
Installing setuptools, pip, wheel...
done.

And then

$> $> which python
/opt/local/bin/python
$> python
>>> import subprocess
>>> subprocess.check_output('/Users/rubendibattista/.envs/test-virtualenv/bin/python -c "import sys; print(sys.executable)"', shell=True)
b'/opt/local/bin/python\n'

[gaborbernat]

Judging from the output of that virtualenv creation you're using the old legacy version of virtualenv (<16.7.9). That's no longer maintained. Please try the latest version 20.0.2 and report back if this is still an issue.

[asottile]

the output is due to framework builds which are particularly fickle, you'll likely need a workaround similar to this

[rdbisme]

I was using the version provided by Macports.

Upgrading virtualenv seems to fix the bug:

$> virtualenv --version
virtualenv 20.0.2 from /opt/local/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/virtualenv/__init__.py

virtualenv $WORKON_HOME/test-virtualenv
created virtual environment CPython3Posix(dest=/Users/rubendibattista/.envs/test-virtualenv, clear=False, global=False) with seeder FromAppData pip=latest setuptools=latest wheel=latest app_data_dir=/Users/rubendibattista/Library/Application Support/virtualenv/seed-v1 via=copy
$> python
>>> import subprocess
>>> subprocess.check_output('/Users/rubendibattista/.envs/test-virtualenv/bin/python -c "import sys; print(sys.executable)"', shell=True)
b'/Users/rubendibattista/.envs/test-virtualenv/bin/python\n'