Support Sphinx post-releases

[CreatingNull]

Fixes #1343, the way this string is being separated was not safe for Sphinx's pypi pre-release/post-release versions.

This includes current release 5.2.0.post0, but also applies to previous pypi beta releases such as 5.0.0b1

As the _ver_bugfix is not being used within templates, we can slice to only include major and minor components.
This avoids issues from the patch component being non-integer as well the len(sphinx_version.split('.')) being > 3.

[rkdarst]

From https://github.com/sphinx-doc/sphinx/issues
/10860#issuecomment-1257236167

RTD's theme should really use the version tuple attribute we provide, rather than somewhat clumsily introspecting the string version.

I guess that is sphinx.version_info, which simplifies the whole thing.

[rkdarst]

from sphinx/builders/html/__init__.py, in self.globalcontext is

            'sphinx_version': __display_version__,
            'sphinx_version_tuple': sphinx_version,

so I guess it is sphinx_version_tuple.

[rkdarst]

But that was only added in sphinx-doc/sphinx@426fdca, which was only added in 4.2 (2021-09-12), so we should definitely still parse the string for a few more years - at least, I would do more.

[AA-Turner]

From sphinx-doc/sphinx/issues /10860#issuecomment-1257236167

RTD's theme should really use the version tuple attribute we provide, rather than somewhat clumsily introspecting the string version.

I guess that is sphinx.version_info, which simplifies the whole thing.

Yes, sphinx.version_info was added in Sphinx 1.2 -- this is what I'd suggest passing into your Jinja templates.

A

[AA-Turner]

If you want to keep the logic in pure Jinja, you could gate the split/map operation on Sphinx versions prior to 4.2, and use the tuple from 4.2 onwards, I believe.

A

[CreatingNull]

I raised this PR as an option to resolve the short-term issue, this is no longer required as Sphinx released 5.2.1.
Closing this PR in favor of someone more familiar with this project / Sphinx extensions to resolve properly.

Personal opinion is we shouldn't be checking the version to determine how to check the version.

Agree with @AA-Turner on his first comment, and since sphinx.version_info is being used for version checks in the python source, it'd make sense to also complete checks within Jinja templates using the data originated from that same tuple.

[pelson]

FWIW I implemented a fix in #1345.