explain why version cannot be retrieved when Requires-Python is not satisfied

[ronaudinho]

resolves #9615.

since logs for links skipped when Requires-Python is not satisfied are suppressed anyway, I decided to utilize those. the resulting error message changed a bit from my comment in the mentioned issue.

[xavfernandez]

Hello, could you paste the updated output from this PR ?

[sbidoul]

@xavfernandez this is how it looks like

[sbidoul]

From the example above I find the displayed message somewhat confusing. The first message says "Could not find a version..." and second says "Found versions that...". But strictly speaking, both are lists of versions that were found. They were ignored for different reasons.

Would it make sense to display the second message (with the list of skipped versions) first, and phrase it with something such as Ignored the following versions that require a different python version: ...) ?

[sbidoul]

@ronaudinho do you think you could do the requested change in the next day or so ? So this can go in 21.1.

[uranusjr]

@ronaudinho Ping on this since we’ll be working on the 21.2 release soon. This can be included if you could address the comment above and rebase the commit against latest main.

[pradyunsg]

@ronaudinho Would it be possible for you to update this PR?

[ronaudinho]

@uranusjr @pradyunsg sorry for the lack of reply, I'll update the PR with @sbidoul 's suggestion in a day or two.

[uranusjr]

We should probably do a refactoring to make the "Requires-Python" in reason check more structured, but this change is a good enhancement as-is.

[uranusjr]

p.s. I merged main to resolve conflicts, so if anyone plans to push more changes, please pull first.

[pradyunsg]

Thanks @ronaudinho for this, and everyone else for the discussion + work on this! ^.^