make ipython works with different python versions cleanly

[laoshaw]

on Linux if I do:

pip3.10 install --user ipython
pip3.11 install --user ipython

They both use the same ipython file at $HOME/.local/bin/ipython, I would expect there are both ipython3.10 and ipython3.11 created so I can specify which python version my ipython is supposed to work with. The default ipython can be whatever the default Python is in the system(in my case it is 3.10 on ubuntu 22.04)

I can create them manually of course, it could be nice if this is created automatically when I have multiple pythons to work with their own ipythons though.

[bollwyvl]

Yeah we tried this, and rolled it back. This is pretty much not going to work with pip-installed artifacts without ipython building a huge matrix of wheels, or building special ipython-python-major-version-entry-point packages Indeed, this is what we had to do on conda-forge to support that feature. Luckily all of that has been rolled back, as well. If you wish to maintain these packages on pypi, go right ahead! More broadly: doing --user installs of binary wheels (or things that depend on them) all but guarantee _something_ will break in the future, due to entirely unmanaged dependencies, and generally can't be recommended for ipython/jupyter tools.

[laoshaw]

so what should we do then, must use virtualenv/venv/pipenv/pipx to handle multiple pythons and ipythons in their sandboxes? and avoid pip-version install --user? I did notice pip3.10|pip3.11 install --user separates their packages nicely already, it's where the $HOME/.local/bin is not working cleanly.

[bollwyvl]

Yes, for each portable, reproducible, interactive computing line of inquiry, it doesn't seem too controversial to recommend maintaining a source-of-truth file for a package manager of choice which can create isolated environments. If a system package manager offers everything required, then that's likely the most robust, but if they all did everything, this wouldn't be an issue. The resolution of $PATH is a case in point, tidily handled by virtual environments, to a certain extent: whatever is in the managed environment "wins," and the lower level system provides what is not managed... Or not. Any any rate, please see the web of issues hanging of the most recent PR for more context #13880, and probably don't hold your breath for this being implemented or reviewed of PRd.