Speedup `os.path`

[nineteendo]

Feature or enhancement

Proposal:

There are (still) some minor optimisations possible in os.path, including some fast returns.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-117349: Speedup os.path #117610

[barneygale]

Duplicate of #117349, please don't do this. The bug tracker is not your personal to-do list.

[nineteendo]

Most PRs will require an issue number. Trivial changes, like fixing a typo, do not need an issue.

Must I link to the closed issue then? This PR is about further changes.

[barneygale]

If you think the previous issue was closed prematurely then you can leave a comment there asking for it to be re-opened.

Please take a look at other issues on the bug tracker to get an idea of what's in and out of scope. We don't generally allow issues like "micro-optimise this entire module" - they're too broad and not useful enough to other developers.

[nineteendo]

If you think the previous issue was closed prematurely then you can leave a comment there asking for it to be re-opened.

Not prematurely, I just found new optimisations.

We don't generally allow issues like "micro-optimise this entire module"

There is a particularly inefficient loop in ntpath: #117610 (comment)
Can I add some other optimisations alongside it?