XSLT Document function returns empty result on Maven POM

Greetings!

I want to extract some properties from different Maven POMs in a XSLT via the document function. The script itself works fine but the document function returns an empty result for the POM as long as I have the xmlns="http://maven.apache.org/POM/4.0.0" in the project tag. If I remove it, everything works fine.

Any idea how the make this work while leaving the xmlns attribute where it belongs or why this doesn't work with the attribute in place?

Here comes the relevant portion of my XSLT:

<xsl:template match="abcs">
 <xsl:variable name="artifactCoordinate" select="abc"/>
   <xsl:choose>
        <xsl:when test="document(concat($artifactCoordinate,'-pom.xml'))">
         <abc>
          <ID><xsl:value-of select="$artifactCoordinate"/></ID>
    <xsl:copy-of select="document(concat($artifactCoordinate,'-pom.xml'))/project/properties"/>
   </abc>
         </xsl:when>
            <xsl:otherwise>
       <xsl:message terminate="yes">
           Transformation failed: POM "<xsl:value-of select="concat($artifactCoordinate,'-pom.xml')"/>" doesn't exist. 
       </xsl:message>
      </xsl:otherwise> 

</xsl:choose>

And, for completeness, a POM extract with the "bad" attribute:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<!-- ... -->
<properties>
    <proalpha.version>[5.2a]</proalpha.version>
    <proalpha.openedge.version>[10.1B]</proalpha.openedge.version>
    <proalpha.optimierer.version>[1.1]</proalpha.optimierer.version>
    <proalpha.sonic.version>[7.6.1]</proalpha.sonic.version>
</properties>
 </project>

Solution

Your problem is that the POM extract uses default namespace. This means that the elements, although unprefixed, are in the "http://maven.apache.org/POM/4.0.0" -- not in the "no namespace".

However, in this XPath expression, in the XSLT code:

document(concat($artifactCoordinate,'-pom.xml'))/project/properties

the names project and properties are unprefixed. XPath always treats unprefixed names as belonging to "no namespace". Hence, no such elements are found and no node is selected.

Solution: Add a namespace definition to your <xsl:stylesheet>, lets say:

  xmlns:p="http://maven.apache.org/POM/4.0.0"

Then rewrite element names in any expressions referencing POM nodes from someElement to p:someElement. For example:

document(concat($artifactCoordinate,'-pom.xml'))/p:project/p:properties