Explain why version cannot be retrieved due to python-requires

[Colin-b]

What's the problem this feature will solve?

I am trying to install a specific version of a package (ipython==7.20.0 in this case). However my version of python is 3.6 and the python-requires of this version is 3.7 at the latest. Leading to pip displaying this upon install request:

ERROR: Could not find a version that satisfies the requirement ipython==7.20.0
ERROR: No matching distribution found for ipython==7.20.0

Describe the solution you'd like

I would like for pip to display that even if this version exists, it cannot be installed as it is incompatible with my python version.

A message like the following would be neat:

ERROR: Could not find a version that satisfies the requirement ipython==7.20.0
ERROR: ipython==7.20.0 was found, however it cannot be installed as your python version (3.6.X) is incompatible with the requirements of this distribution (>=3.7).

Now that more and more python modules are dropping support for python 3.6 (pandas, numpy, werkzeug from the top of my head) while python 3.6 is still heavily used, I am fairly certain the number of users facing this rejection is high.

The message is not clear enough to understand in one go what the issue was and forces the developer in question to investigate. While pip already did the investigation, but did not shared the reason.

It's maybe a long shot but it would be even better if the message could provide the latest compatible version for such project (if any).

Thanks for your time

[uranusjr]

Sounds reasonable, but the implementation would be much less straightforward than it would seem at first glance. Python package distribution is file-based, not version-based, so it does not actually make sense to say “ipython==7.20.0 was found but cannot be installed due to Requires-Python” because different files for the specified version may have different specifiers. The logic to come up with a comprehensive message may not be too difficult, but will be tedious and require time. I would welcome anyone interested to try their hands on this; it’d be a fun excersise to walk you through some interesting aspects of Python packaging.

[ronaudinho]

I guess something like this would do?

[Colin-b]

I guess something like this would do?

Yes it would!