Re: [TECH TOPIC] Kernel documentation - update and future directions

[Mauro Carvalho Chehab <mchehab+huawei@kernel.org>]

Em Wed, 03 Sep 2025 12:45:25 +0200
Johannes Berg <johannes@sipsolutions.net> escreveu:

> On Wed, 2025-09-03 at 12:42 +0200, Mauro Carvalho Chehab wrote:
> > > For example, use case we have: using nix-shell to lock down the software
> > > used to build, for reproducible builds and similar reasons. Without --
> > > pure, PATH may still contain (last!) software from the system itself,
> > > but it should basically never be used.  
> > 
> > if the PATH is mangled, you'll have a lot more problems than just
> > building docs as it will pick wrong exec files anyway.  
> 
> Err, no? To search a binary, directories in $PATH are meant to be
> searched in order of appearance. It's well-defined which one you pick
> for which, and this setup takes advantage of that (with a rather long
> $PATH) to control the binaries used for the build.

Yes. So? the logic does that.

> > In the particular case of docs, if you have, for instance, two different
> > python versions, one with sphinx and another one without it, it may pick
> > the wrong one, causing the build to fail. There's nothing the build system
> > can do to solve it. The proper fix would be to wrap the calling logic
> > to save the env before running under nix-shell, restoring env afterwards.  
> 
> 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.

The build logic does follow PATH. If python --version < 3.7, it will
seek, within PATH, for python > 3.6.

Thanks,
Mauro