Why mixing python3 versions?

[alanwilter]

I use python3 and the one that brew points is v3.9.9.

All seemed to be happy until I wanted to use ipython, which installs python 3.10!!!.

Why that? I found out to my displeasure surprise that there are other apps using this python 3.10: pipx and thefuck. Those one I don't care but ipython???

I'll illustrate with an exemple:

brew install ipython
brew install open-babel

Start ipython and try:

import openbabel
ModuleNotFoundError: No module named 'openbabel'

But, with python3 it will work.

Bottomline, ipython need to use the same python3 shipped by default with brew. If this is not at least an inconsistency, to not say a bug, then what's the logic behind it?

Is there an alternative to force ipython from brew to use same python 3.9.9?

And yes, I know and I did: brew uninstall ipython and /usr/local/bin/python3 -m pip install ipython.
However, what's the point then that instead of simply running bubu I have to remember to to run pip install ipython -U as well?

Or, is it anyhow related to Homebrew/homebrew-core#76621?

[carlocab]

We're in the process of migrating all formulae to depend on Python 3.10. There are a lot of those, so it takes some time. You're welcome to help out if you wish.

[alanwilter]

Well, I can help, definitely! What do I need to do?

[suletm]

It's been a while since the last follow-up on this thread. It's unclear if the help is still needed or not. It would be less-disruptive to finish the migration and only then make the switch of the ipython version to use 3.10, would not it ? The issue is still there with Homebrew 3.5.4.

[alebcay]

Hi @suletm, more details are tracked on Homebrew/homebrew-core#87075. You can view all pull requests that have been opened regarding moving to Python 3.10 with https://github.com/Homebrew/homebrew-core/pulls?q=is%3Apr+sort%3Aupdated-desc+label%3Apython-3.10-migration+.

At the time of writing, there have been 481 pull requests with that label, so I would hardly consider such a change "less disruptive". Part of the migration effort has also involved splitting several Python-dependent formulae (each of which has many dependents) into smaller formulae - glib (migration effort at Homebrew/homebrew-core#103916) and python-tabulate (migration effort at Homebrew/homebrew-core#99064) to make the migration less painful.