In the old version picker used back in 3.5 [1], the function patch_url was patching using the following regex:

    var url_re = /\.org\/(\d|py3k|dev|((release\/)?\d\.\d[\w\d\.]*))\//,

which does not expects a language tag.

This means, for example, that being on https://docs.python.org/fr/3.5/library/__main__.html and switching to 3.6 will fail (but the reverse will succeed as the implementation of the switcher in 3.6 understands the language tag).

I see two potential fixes:

- Fix in the 3.5 branch which is not allowed as the branch is in "security only" mode.
- Add a rule, nginx-side, to fix the misconstructed URLS (looking like /3.6/fr/3.5/library/...) redirectin g them to the right place.

Other ideas and feedback welcome.


[1]: https://docs.python.org/fr/3.5/_static/version_switch.js

3rd possibility, docsbuild-scripts could also apply a patch during the doc compilation.

> Fix in the 3.5 branch which is not allowed as the branch is in "security only" mode.

I think you could appeal to the 3.5 Release Manager that this should go in.  Since the 3.5 docs are only rebuilt manually these days (I think), in the worst case the current 3.5 on-line docs would not reflect the change until the next 3.5.x security release.

Hi Larry, bringing you in, I'd like your word on this.

Doc fixes are generally okay in security-fixes-only branches.  Obviously I'd want to review it before it went in; it sounds like a simple change (one line change to an RE?), so you can send me a PR or just post it here if you want a pre-review.

New changeset 1b141b9553424971639bde281feb1d4e4e586dbe by larryhastings (Julien Palard) in branch '3.5':
Doc: Backport language switcher (bpo-33700, bpo-31045) (#8048)
https://github.com/python/cpython/commit/1b141b9553424971639bde281feb1d4e4e586dbe