POC: Type-safe name canonicalization

[uranusjr]

This is a proof of concept for #7974.

I introduced a wrapper function pip._internal.utils.packaging.canonicalize_name() to return a new type CanonicalName, and tried that on FormatControl. Seems to work pretty well, it initially reported quite a few type errors, and I could convert the required hints quite easily by following the error messages.

[pradyunsg]

But pypa/packaging#292... :(

[uranusjr]

This is just a POC :)

We only need to change the imports (back) with your change merged in.

[pradyunsg]

Oh come on, why is RTD not reporting status now?

[McSinyx]

@pradyunsg, RTD builds fine, could be GitHub issue? On my personal repos there are times where Travis has the same problem (successful build but showed as pending on GH checks).

[pradyunsg]

Yea, it's probably a case of a GitHub outage overlapping with when the result was posted back. RTD's not a blocker for merging PRs though, so it's fine. :)

[BrownTruck]

Hello!

I am an automated bot and I have noticed that this pull request is not currently able to be merged. If you are able to either merge the master branch into this pull request or rebase this pull request against master then it will be eligible for code review and hopefully merging!

[pradyunsg]

FWIW, packaging 20.4 now has the relevant changes included. Whenever we re-vendor that, we'll have to addresss this issue (mostly).