Re: [xslt] An Invalid xpath expression xsl:template/@match node is ignored

[Nicolas Delaby <nicolas deliveryhero com>]

On 07/31/2012 07:28 PM, Nick Wellnhofer wrote:
> On 31/07/2012 17:46, Nicolas Delaby wrote:
> > Dear libxslt maintainers,
> > I discover that performing a transformation with a invalid xpath
> > expression in a template match attribute doesn't prevent the
> > transformation to perform and lead to compromise the transformation
> > logic.
> > Instead, I would expect to have a proper failure like `could not compile
> > match expression`
>
> The way I read it, this behavior doesn't violate the specification.
> Section 17 "Conformance" says:
>
> "A conforming XSLT processor must signal any errors except for those
> that this document specifically allows an XSLT processor not to signal.
> A conforming XSLT processor may but need not recover from any errors
> that it signals."
>
> libxslt does signal the error and tries to recover by ignoring the
> template.
Hi Nick,
Thanks for your answer
I see the point.

But if I change a bit my stylesheet to put the invalid xpath expression 
in a xsl:apply-templates/@select , it does try to continue the 
transformation.

[...]
<xsl:apply-templates select="sub_node1||sub_node2" />
[...]

$ xsltproc xpath-typo.xsl document.xml
XPath error : Invalid expression
sub_node1||sub_node2
          ^
compilation error: file xpath-typo.xsl line 6 element apply-templates
XSLT-apply-templates: could not compile select expression 
'sub_node1||sub_node2'
error: file xpath-typo.xsl line 10 element template
xsltCompilePattern : NULL pattern

Why it stops here ?
I guess the compiler can not recover from this error, so it doesn't have 
other choice than stopping. But may be there is another explanation ?

IMHO, I do not like this strategy to recover from errors automatically.

Apart from my personal opinion :), the only way to know if something 
goes wrong is to read stderr right ? Or is there is something more 
explicit ?

Thanks again,
Nicolas
--
Nicolas Delaby | IT Developer | IT Department

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