Re: make pdfdocs fails with v4.9-rc3

[Mauro Carvalho Chehab <mchehab@infradead.org>]

Em Mon, 31 Oct 2016 15:04:42 -0700
Jim Davis <jim.epost@gmail.com> escreveu:

> On Mon, Oct 31, 2016 at 1:58 PM, Mauro Carvalho Chehab
> <mchehab@infradead.org> wrote:
> > Em Mon, 31 Oct 2016 14:17:59 -0600
> > Mauro Carvalho Chehab <mchehab@infradead.org> escreveu:
> >  
> >> Em Mon, 31 Oct 2016 13:15:24 -0600
> >> Jonathan Corbet <corbet@lwn.net> escreveu:
> >>  
> >> > On Mon, 31 Oct 2016 11:51:20 -0700
> >> > Jim Davis <jim.epost@gmail.com> wrote:
> >> >  
> >> > > Running make pdfdocs on a Ubuntu 16.04 system fails with
> >> > >
> >> > > Makefile:58: recipe for target 'media.pdf' failed
> >> > > make[2]: *** [media.pdf] Error 1
> >> > > Documentation/Makefile.sphinx:79: recipe for target 'pdfdocs' failed
> >> > > make[1]: *** [pdfdocs] Error 2
> >> > > Makefile:1442: recipe for target 'pdfdocs' failed
> >> > > make: *** [pdfdocs] Error 2
> >> > >
> >> > > It's not clear from the voluminous (>5MB) output from make pdfdocs
> >> > > exactly which stage is failing, and there are some pdf files produced
> >> > > in output/latex.  
> >> >
> >> > Hmm, so it does.  It comes down to this:
> >> >
> >> > ! LaTeX Error: \DUrole undefined.
> >> >
> >> > See the LaTeX manual or LaTeX Companion for explanation.
> >> > Type  H <return>  for immediate help.
> >> >  ...
> >> >
> >> > l.195 \renewcommand*{\DUrole}
> >> >                              [2]{ #2 }
> >> >
> >> > Where the offending command is in Documentation/media/index.rst.  Mauro,
> >> > got an idea for what's going on there?  
> >>
> >> Sphinx is really a poor solution when it comes to PDF output. In this
> >> specific case, this is meant to fix a problem with cross-references.
> >>
> >> What happens is that Sphinx 1.4.6 (and later?) define reference names without
> >> being properly escaped. So, for some references, it causes the PDF output
> >> to crash. That happens at one of the DVB header files, if I remember well.
> >>
> >> This commit restores the sphinx 1.2.x behavior:
> >>
> >>     commit e61a39baf74dddb6cd236147bd19b55c10188d78
> >>     Author: Mauro Carvalho Chehab <mchehab@s-opensource.com>
> >>     Date:   Sun Aug 21 15:14:57 2016 -0300
> >>
> >>     [media] index.rst: Fix LaTeX error in interactive mode on Sphinx 1.4.x
> >>
> >>     The Sphinx 1.4.x definition for \DUrole is:
> >>
> >>     \providecommand*{\DUrole}[2]{%
> >>       \ifcsname DUrole#1\endcsname%
> >>         \csname DUrole#1\endcsname{#2}%
> >>       \else% backwards compatibility: try \docutilsrole#1{#2}
> >>         \ifcsname docutilsrole#1\endcsname%
> >>           \csname docutilsrole#1\endcsname{#2}%
> >>         \else%
> >>           #2%
> >>         \fi%
> >>       \fi%
> >>     }
> >>
> >>     This is broken when it is used inside a \begin{alltt} block.
> >>     So, replace it by just "#2", as this won't cause troubles, and
> >>     it is one of the fallback methods for it.
> >>
> >>     Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
> >>
> >> At the time I tested, it worked fine, but maybe it is redefining the
> >> \DUrole too late.
> >>
> >> Maybe we could move it to LaTeX preamble instead. Please check if this
> >> untested patch fixes the issue.  
> >
> > Yes, this seems to be the case. The patch below should fix it.
> >
> > [PATCH] docs-rst: fix PDF build errors
> >
> > PDF build on Kernel 4.9-rc? returns an error. This is
> > because we're re-defining a command too late. Move
> > such redefinition to LaTeX preamble.
> >
> > Tested by building the documentation on interactive mode:
> >         make PDFLATEX=xelatex -C Documentation/output/./latex
> >
> > Fixes: e61a39baf74d ("[media] index.rst: Fix LaTeX error in interactive mode on Sphinx 1.4.x")
> >
> > Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
> >
> > diff --git a/Documentation/conf.py b/Documentation/conf.py
> > index d9bad21dd427..d9ebfeb431a9 100644
> > --- a/Documentation/conf.py
> > +++ b/Documentation/conf.py
> > @@ -329,6 +329,9 @@ latex_elements = {
> >         % To allow adjusting table sizes
> >         \\usepackage{adjustbox}
> >
> > +       % Fix reference escape troubles with Sphinx 1.4.x
> > +       \\renewcommand*{\\DUrole}[2]{ #2 }
> > +
> >       '''
> >  }
> >
> > diff --git a/Documentation/media/index.rst b/Documentation/media/index.rst
> > index e347a3e7bdef..7f8f0af620ce 100644
> > --- a/Documentation/media/index.rst
> > +++ b/Documentation/media/index.rst
> > @@ -1,11 +1,6 @@
> >  Linux Media Subsystem Documentation
> >  ===================================
> >
> > -.. Sphinx 1.4.x has a definition for DUrole that doesn't work on alltt blocks
> > -.. raw:: latex
> > -
> > -       \renewcommand*{\DUrole}[2]{ #2 }
> > -
> >  Contents:
> >
> >  .. toctree::
> >
> >
> >
> >
> > Cheers,
> > Mauro  
> 
> After applying the patch I'm seeing a similar error message
> 
> [...]
> Running Sphinx v1.3.1
> [...]

Ah! you're running version 1.3.1...

We should likely add some logic at conf.py to only enable this on
Sphinx 1.4.x...

Cheers,
Mauro