XSLT processing error: global variables not seen in predicates

[Yuri Baranov]

Binary package hint: libxslt1.1

It seems that xslt processing engine could not see global variables inside xsl predicates' conditions.
(See attached file xsltprocbug1.xsl)

Running
$xsltproc xsltprocbug1.xsl xsltprocbug1.xsl
gives the following output:
-----cut-----
XPath error : Undefined variable
compilation error: file xsltprocbug1.xsl line 4 element template
Failed to compile predicate
-----cut-----

Line 4 just references a global variable, defined earlier inside a predicate
4: <xsl:template match="*[.=$hello]">

Similar behavior occurs when I am using libxslt from my own application.

NB: When using global variable outside the predicate, like in <xsl:value-of select="$hello" />, the processor gives no complaints.

Other XSLT processors,e.g. xalan do process this example template without reporting any errors.

ProblemType: Bug
Architecture: i386
DistroRelease: Ubuntu 9.04
Package: libxslt1.1 1.1.24-2ubuntu2
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: libxslt
Uname: Linux 2.6.28-11-generic i686

[Jurjen Oskam (jurjeno)]

According to http://bugzilla.gnome.org/show_bug.cgi?id=303289 the behaviour you see is correct, because the standard doesn't allow for variables in the match attribute.

(Note that I'm an xml/xslt newbie, and I may very well be wrong. The description of the bug is awfully similar though.)

[Yuri Baranov (baranov)]

Thank you, Jurjen!
This is quite an unituitive feature of XSLT - forbidding any variable reference in match attribute.
I should have looked up the specification myself, sorry!

Obviously, xalan & some other processors silently extend the specification, while xsltproc/libxslt sticks to it.

It would be nice, if xslt could emit a more user-friendly message, though. Something like
'variable references are prohibited in match attributes' rather than 'undefined varibale',
which leads to misunderstanding.