Using app.add_css_stylesheet() in conf.py

[diego-plan9]

When attempting to build the documentation using latest sphinx (4.2.0) (related to an effort of packaging oauthenticator into Debian), an error is raised due to:

app.add_stylesheet('custom.css')

at conf.py.

It seems .add_stylesheet() has been technically deprecated since quite a while (1.8), although not really remove from sphinx until recently - while it might get reintroduced and supported until 6.0 (sphinx-doc/sphinx#9683), would it make sense to replace it with its .add_css_stylesheet() successor, for some future-proofing? Actually, I could not trace the referenced custom.css - not sure if an alternative would be to simply drop the line altogether.

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[consideRatio]

Absolutely, sounds very reasonable! Let's transition to add_css_stylesheet and make us require sphinx >=2 if we don't already do.

Actually, I could not trace the referenced custom.css - not sure if an alternative would be to simply drop the line altogether.

OH! Nice catch! Removing it or commenting it out seems like a good idea to me - better than retaining it with a reference that doesn't exist.

[tk0miya]

would it make sense to replace it with its .add_css_stylesheet() successor, for some future-proofing?

I think it's better to use the html_css_file configuration instead of the add_css_file() API (if you still need to install custom CSS).
https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-html_css_files