[Python-Dev] PEP-582 and multiple Python installations (original) (raw)

Chris Barker - NOAA Federal chris.barker at noaa.gov
Thu Apr 4 12:02:00 EDT 2019

I'd like to raise a potential edge case that might be a problem, and likely an increasingly common one: users with multiple installations of the same version of Python.

I would suggest that that use case is best addressed by a system that isolates the entire python environment, such as conda.

This is actually a common setup for Windows users who use WSL, Microsoft's Linux-on-Windows solution, as you could have both the Windows and Linux builds of a given Python version installed on the same machine.

Sure, but Isn’t the WSL subsystem pretty isolated already? Would native Windows and WSL users be running in the same dir?

That being said, I’m pretty skeptical of the PEP — I understand the motivation — I make a point of avoiding virtual environments in my intro classes, but at some point folks will need to learn them.

I’ve had students think that virtualenv was a part of (or required by) e.g. flask, because the tutorials include it in the setup.

But I think environments really need to be more distinct, not less, I’m quite concerned about mingling them in one place.

Maybe I’m reading it wrong, but it seems that this could create serious clashes with other “environment” systems, such as conda.

I suppose one could say: “don’t do that” — I.e. don’t create a pypackages dir if you are going to use conda — but many folks want the same source to be runnable in multiple “styles” of Python.

Also, I see a major benefit for teaching, but it does go a bit against my philosophy of not hiding important details from newbies — that is, don’t teach using an approach that is not suitable for production.

And newbies could be really confused by the fact that pip installs stuff differently depending on what dir they are in and what is in that dir.

The PEP is listed as a draft — anyone know what’s going on with it?

-CHB

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