venv.create() fails when sys._base_executable is empty

[meeuw]

Bug report

venv.create() fails when sys._base_executable is empty.

This happens when Python cannot determine the base_executable when it's started without a full path and PATH is empty:

$ env -i python
Python 3.10.6 (main, Aug  2 2022, 00:00:00) [GCC 12.1.1 20220507 (Red Hat 12.1.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys ; print(sys._base_executable)

>>> 

$ env -i python -mvenv /tmp/dmtest
Unable to symlink '' to '/tmp/dmtest/bin/meeuw'
Error: [Errno 2] No such file or directory: ''

Your environment

• CPython versions tested on: 3.10.6
• Operating system and architecture: linux / x86_64

Would it be possible to raise an exception when sys._base_executable is empty with a sane error message?

Related to: python-poetry/install.python-poetry.org#43

[vsajip]

This isn't a bug in venv. If you do env -i python, then sys.executable is set to the empty string, so lots of things would break.

[meeuw]

I'm not so sure about that, the documentation describes that sys.executable can be empty:

If Python is unable to retrieve the real path to its executable, sys.executable will be an empty string or None.

I think it makes sense for venv to error out with a proper error message. For example start python using a full path or set a PATH where python can be found.