Re: DOCBOOK-APPS: Problem using profiling stylesheets with xsltproc

[Bob Stayton <bobs@caldera.com>]

On Sat, Nov 30, 2002 at 08:25:11PM -0600, John Himpel wrote:
> Hi,
> 
> When I use the following command:
> 
> xsltproc  \
>   --catalogs \
>   --nonet \
>   --xinclude \
>   --output ./html/${1}.html \
>   --stringparam profile.condition FullRel \
>  file:///usr/share/sgml/docbook/xsl-stylesheets/html/profile-docbook.xsl
> \
>   ${1}.xml   
> 
> on the following file:
> 
> <?xml version='1.0' encoding='utf-8' ?>
> <!DOCTYPE article PUBLIC '-//OASIS//DTD DocBook XML V4.2//EN'
>                         
> 'http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd' >
> 
> <article>
>   <title>Title</title>
>   <section condition="FullRel">
>     <title>FullRel</title>
>     <para>FullRel para</para>
>   </section>
>   <section condition="UpdateRel">
>     <title>UpdateRel</title>
>     <para>UpdateRel para</para>
>   </section>
> </article>
> 
> I get the following output:
> 
> runtime error: file
> file:///usr/share/sgml/docbook/xsl-stylesheets/html/profile-docbook.xsl
> line 219 element apply-templates
> xsltApplyOneTemplate: loop found ???
> try increasing xsltMaxDepth (--maxdepth)
> Templates:
> #0 name * name head.keywords.content 
> #1 name * name head.keywords.content 
> #2 name * name head.keywords.content 
> #3 name * name head.keywords.content 
> #4 name * name head.keywords.content 
> #5 name * name head.keywords.content 
> #6 name * name head.keywords.content 
> #7 name * name head.keywords.content 
> #8 name * name head.keywords.content 
> #9 name * name head.keywords.content 
> #10 name * name head.keywords.content 
> #11 name * name head.keywords.content 
> #12 name * name head.keywords.content 
> #13 name * name head.keywords.content 
> #14 name * name head.keywords.content 
> Variables:
> 
> Using the following versions:
> LIBXML2 2.4.23 (libxml2-2.4.23-1 from RedHat)
> LIBXSLT 1.0.19 (libxslt-1.0.19-1 from RedHat)
> DTD 4.2.1 (docbook-dtds-1.0.14 from RedHat)
> XSL Stylesheets 1.57.0 (docbook-style-xsl-1.57.0-2 from RedHat)
> 
> 
> I don't know if:
> a) I'm doing something wrong
> b) The stylesheets have a problem
> c) XSLTPROC has a problem

You aren't doing anything wrong.  But you can work around
it by setting the stylesheet parameter inherit.keywords to
zero.

I think it is a bug in xsltproc.
The problem is that in the template named
"head.keywords.content", there is a recursive
call to the same template.

  <xsl:if test="$inherit.keywords != 0 and parent::*">
    <xsl:apply-templates select="parent::*" mode="head.keywords.content"/>
  </xsl:if>

In profile-docbook.xsl, this recursive template goes into
an infinite loop.  The same template is in docbook.xsl, and
it does not go into an infinite loop.  Nor does Saxon go
into an infinite loop when processing with
profile-docbook.xsl.

The loop should stop when it reaches the root node.
xsltproc keeps going with <article>, somehow thinking
the parent of article is article.

Since this doesn't occur with the same template in
docbook.xsl, it would appear that the difference is that
profile-docbook.xsl is operating on a exslt nodeset. But I
can't explain it any further than that.

Bob Stayton                                 400 Encinal Street
Publications Architect                      Santa Cruz, CA  95060
Technical Publications                      voice: (831) 427-7796
The SCO Group                               fax:   (831) 429-1887
                                            email: bobs@sco.com