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Date:   Wed, 29 May 2019 20:20:05 -0300
From:   Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
To:     Jonathan Corbet <corbet@lwn.net>
Cc:     Linux Doc Mailing List <linux-doc@vger.kernel.org>,
        Mauro Carvalho Chehab <mchehab@infradead.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/5] docs: by default, build docs a lot faster with
 Sphinx >= 1.7
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Em Wed, 29 May 2019 17:02:02 -0600
Jonathan Corbet <corbet@lwn.net> escreveu:

> On Mon, 27 May 2019 08:07:40 -0300
> Mauro Carvalho Chehab <mchehab+samsung@kernel.org> wrote:
> 
> > Since Sphinx version 1.7, it is possible to use "-jauto" in
> > order to speedup documentation builds. On older versions,
> > while -j was already supported, one would need to set the
> > number of threads manually.
> > 
> > So, if SPHINXOPTS is not provided, add -jauto, in order to
> > speed up the build. That makes it *a lot* times faster than
> > without -j.
> > 
> > If one really wants to slow things down, it can just use:
> > 
> > 	make SPHINXOPTS=-j1 htmldocs
> > 
> > Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
> > ---
> >  Documentation/Makefile | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/Documentation/Makefile b/Documentation/Makefile
> > index 380e24053d6f..794233d05789 100644
> > --- a/Documentation/Makefile
> > +++ b/Documentation/Makefile
> > @@ -28,6 +28,8 @@ ifeq ($(HAVE_SPHINX),0)
> >  
> >  else # HAVE_SPHINX
> >  
> > +SPHINXOPTS = $(shell perl -e 'open IN,"sphinx-build --version |"; while (<IN>) { if (m/([\d\.]+)/) { print "-jauto" if ($$1 >= "1.7") } ;} close IN')
> > +  
> 
> So this totally fails to work for me with any version of sphinx, and I'm
> not enough of a Perl person to figure it out.  Sometimes I'll see the
> sphinx-build output, i.e.:
> 
>     sphinx-build 1.8.4
> 
> and sometimes (like with 2.0) I don't, but I never get -jauto regardless.

Hmm... with 2.0.0 --version prints the version.

	$ sphinx-build --version
	sphinx-build 2.0.0

Afaikt, only too old versions will output it with a different format:


	$ sphinx-build --version
	Sphinx (sphinx-build) 1.2


> Not sure what's going on here?

Do you have SPHINXOPTS already set on your environment? If so, Makefile
will not override the existing environment.

Here, if I call it by hand (replacing $$1 by $1), it does the right
thing. For example:

1.8.4:

	$ sphinx-build --version
	sphinx-build 1.8.4
	$ perl -e 'open IN,"sphinx-build --version |"; while (<IN>) { if (m/([\d\.]+)/) { print "-jauto\n" if ($1 >= "1.7") } ;} close IN'
	-jauto

2.0.0:
	$ sphinx-build --version
	sphinx-build 2.0.0
	(sphinx_2.0) $ perl -e 'open IN,"sphinx-build --version |"; while (<IN>) { if (m/([\d\.]+)/) { print "-jauto\n" if ($1 >= "1.7") } ;} close IN'
-jauto


Thanks,
Mauro