Re: [PATCH v2] docs: sphinx-pre-install: warn about unsupported Docutils versions

[Masaharu Noguchi <nogunix@gmail.com>]

Hi Akira,

On Tue, 15 Sep 2026 16:52:03 +0900, Akira Yokosawa wrote:
> I think this can annoy people who only care HTML docs.
>
> Why not do this check after the PDF doc builds have actually failed.
>
> That is what sphinx-build-wrapper is doing with LatexFontChecker().check()
> (see line 557 of tools/docs/sphinx-build-wrapper)

You are right, and that is a better place for it.  v3 follows it: the
check moves into tools/lib/python/kdoc/docutils_version.py, shaped like
latex_fonts.py, and sphinx-build-wrapper calls it from the same two
build_failed branches, next to LatexFontChecker.  sphinx-pre-install is
left untouched.

Measured on a broken pair: htmldocs now prints nothing new and still
exits 0, and the message appears only when pdfdocs has actually failed,
just above the error.  A working pair stays quiet in both.

Thank you for pointing at Ubuntu 26.04 LTS; that turned out to be the
strongest case for having this at all, so I checked it.  It has Sphinx
8.2.3 with Docutils 0.22.4, and its python3-sphinx depends on
"python3-docutils (>= 0.20)" with no upper bound at all, where Fedora 44
arrives at the same pair by patching the "<0.22" that Sphinx declares.
Both fail the same way here:

	              core-api            admin-guide
	---------------------------------------------------------
	Ubuntu 26.04  FAILS 26x Dim       FAILS capacity, 13 p
	Fedora 44     FAILS 26x Dim       FAILS capacity, 13 p

An LTS makes this a good deal less transient than Fedora 44 alone.

v3 follows shortly.

Thanks,
Masaharu