Question

I encountered a peculiar difference in xslt behavior when the root element has a default namespace attribute as opposed to when it does not.
I am wondering why this difference occurs.

The XML input is

<root>
    <content>xxx</content>
</root>

When the following transformation is applied

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:output method="xml" indent="yes"/>

    <xsl:template match="/">
        <root>
            <xsl:apply-templates/>
        </root>
    </xsl:template>

    <xsl:template match="content">
        <w>x</w>
    </xsl:template>

</xsl:stylesheet>

the result is the expected

<?xml version="1.0" encoding="UTF-8"?>
<root>
    <w>x</w>
</root>

But when the same transformation is applied to

<root xmlns="http://test.com">
    <content>xxx</content>
</root>

the result is different and based on the application of just default templates (which effectively output the text node value ‘xxx’):

<?xml version="1.0" encoding="UTF-8"?>
<root>xxx</root>

Addition

When this is the expected behavior in this case, then what match attribute value is needed to match the content element in the second case?

Answer 1

so what exactly is your question? If you’re simply looking for an explanation, following is a brief one. What you’re observing is the proper behavior according to the specification. When you put a namespace on something, the parser essentially treats it as a different element entirely (than an element of the same name but no namespace). Therefore, in the second situation, when you say <xsl:template match="content">, it doesn’t match the <content> element in the XML file because it falls under the http://test.com namespace (by way of the namespace declaration on its parent). Therefore, the default templates take over.