Re: [docbook-apps] WARNING: cannot add @xml:base to node set root element. Relative paths may not work.

["Bob Stayton" <bobs@sagehill.net>]

I don't think Saxon itself supports XIncludes.  Saxon uses the Xerces parser 
with the XInclude function turned on:

http://www.saxonica.com/documentation/sourcedocs/controlling-parsing.html

The XInclude spec says that xml:base attributes must be relative to the 
closest ancestor xml:base. I'm pretty sure that is how Saxon 6 behaves.  If 
Saxon9 is generating xml:base attributes always relative to the top level, 
then that is not what the XInclude spec says, nor what the DocBook 
stylesheet expects.

Bob Stayton
Sagehill Enterprises
bobs@sagehill.net

--------------------------------------------------
From: "Alexey Neyman" <stilor@att.net>
Sent: Tuesday, May 14, 2013 10:25 AM
To: <docbook-apps@lists.oasis-open.org>
Cc: "Bob Stayton" <bobs@sagehill.net>; "Lars Vogel" <lars.vogel@gmail.com>
Subject: Re: [docbook-apps] WARNING: cannot add @xml:base to node set root 
element. Relative paths may not work.

> Hi Lars, Bob,
>
> Just one point: xsltproc does xml:base fixup on nodesets included through
> XInclude, so inside the document there are xml:base elements added 
> properly.
> However, Bob's point still stands: if the top-level document is in 
> non-current
> directory, it will break the external references.
>
> Speaking of Saxon, I am not sure if it does xml:base fixup properly on
> XIncluded modular documents from different directories. Originally, I was
> investigating a bug in libxml2 regarding xml:base fixup (pushed to master,
> will be in the next release), but I also tried Saxon. Here is a link to 
> the
> thread on libxml2 mailing list (which has a small test case attached):
>
>  https://mail.gnome.org/archives/xml/2013-April/msg00024.html
>
> In brief, Saxon seems to emit xml:base relative to top-level document 
> rather
> than to the most recent point of inclusion. DocBook stylesheets (at least,
> 1.78.0 that I used) assume the location relative to the base of the 
> including
> nodeset. xsltproc conforms to the expectations of DocBook stylesheets, and 
> as
> far as I understand, to the XInclude specification.
>
> Regards,
> Alexey.
>
> On Tuesday, May 14, 2013 09:01:37 am Bob Stayton wrote:
> > Hi Lars,
> > You should get that message only when two conditions are met:
> >
> > 1.  You are processing a DocBook 5 document with the non-namespaced
> > stylesheets. or
> >     You are single-step profiling by using profile-docbook.xsl (probably
> > your case).
> >
> > and
> >
> > 2.  You are using xsltproc (which lacks an extension function to get the
> > name of the current directory).
> >
> > With either condition in (1), the document is preprocessed into an 
> > internal
> > nodeset (a nodeset held in memory) before being processed by the
> > stylesheets.  The internal nodeset loses all contact with the filesystem
> > where the files originated, so the preprocessing template tries to add
> > relative directory references into the internal nodeset by adding 
> > xml:base
> > attributes to preserve the relative locations.  It uses an extension
> > function to get the original base directory of the document, but xsltproc
> > does not have a function to fetch that information, while Saxon and Xalan
> > do.
> >
> > So if you use modular doc and the modules are in various directories, 
> > that
> > directory structure  information gets lost in the internal subset.  If
> > your documents don't need such xml:base attributes, then it has no effect
> > on your output.
> >
> > You can avoid it by either using Saxon, or by using two-step profiling.
> >
> > Bob Stayton
> > Sagehill Enterprises
> > bobs@sagehill.net
> >
> >
> > From: Lars Vogel
> > Sent: Tuesday, May 14, 2013 7:13 AM
> > To: DocBook Apps
> > Subject: [docbook-apps] WARNING: cannot add @xml:base to node set root
> > element. Relative paths may not work.
> >
> >
> > Hello,
> >
> >
> > since a while I get the following warning during the transformation with
> > the docbook distribution:
> >
> >
> > WARNING: cannot add @xml:base to node set root element.  Relative paths 
> > may
> > not work.
> >
> >
> >
> > I'm not sure what triggers this warning, a Google search resulted in 
> > hints
> > about Docbook V5.0 but I'm still using Docbook 4.5.
> >
> >
> > I'm currently using the docbook-xsl-1.77.1 distribution and I think (but
> > I'm not sure) that I have this warning since I upgraded from 1.76. The
> > output looks ok to me, but this warning does not create a warm fussy
> > feeling. ;-)
> >
> >
> > Any hint how to get rid of this warning?
> >
> >
> >
> > Best regards, Lars