On Wed, Sep 03, 2025 at 04:57:15PM +0200, Mauro Carvalho Chehab wrote: > On Wed, Sep 03, 2025 at 12:54:04PM +0200, Johannes Berg wrote: > > On Wed, 2025-09-03 at 12:45 +0200, Johannes Berg wrote: > > > > > > I don't follow. If this setup breaks the build then that's good, I'll > > > fix the env. If the build does magic inside and sort of ignores $PATH, > > > that's bad. > > > > Or maybe it's not ignoring $PATH, but rather picking the "best" > > python3.xy binary from $PATH - still that's annoying because you'd have > > to control which ones are there and/or know which ones it might pick. > > > > Far more predictable and usable to just use "python3" and print a > > message saying you might want to use a better version if you think it's > > too slow. > > There are actually 3 different issues that depend on python version: > > 1. sphinx-pre-install: > > This used to be a Perl script. The goal is to check if sphinx-build > is installed and works, and identify missing dependencies. > > The problem is: if one installs python3xx-Sphinx, instead of > python3-Sphinx, the script will fail, except if it first switches > to python3.xx; > > 2. sphinx-build logic inside makefile, required for doc-specific targets: > > - If python < 3.7, doc builds fail; > - If python3xx-Sphinx is installed, build only works if started using > the right python3.xx exec > > 3. kernel-doc via command line. Python >=3.6 and <= 3.11 works. It is > just 60% slower. > > For (3), I agree with you: let it run at the slow way, printing a warning; > eventually suggesting a newer version and, as Jon suggested, added a > command line like --newest-python that could optionally pick the fastest > version. > > Now, for (1) and (2), it should be possible to allow building docs even > if the distro requires Python < 3.7, providing extra packages for newer > Python, as almost all distros do. See, several distros require python > on their minimal install images, because it can be using during package > install. Removing the default python replacing by a new version may break > the system, as the newer version may not be backward-compatible. > > So, what distros do, instead, to ensure backward-compatibility is to > provide multpile Python versions (together with python libraries). > > The htmldocs/pdfdocs/... targets must support it somehow. > > The best alternative seems to check if: > > - python version is bellow the minimal supported version; > - there is a newer python binary at PATH; > - check if sphinx-build runs with the newest version. > > If all those 3 conditions are met, build docs with a version that works, > printing a message to tell the user what Python binary was used. This should fail. If you really insist you could print a message telling the user there's another Python version on their system that may work, but selecting it automatically isn't a good idea. -- Regards, Laurent Pinchart
