Hi Andrew,

A precious observation; it appears there isn’t a single test case for that in the W3 test suite. We’ll fix it with the next release; until then, you can use head(id(...)).

Thank you, Christian

On Wed, Jul 24, 2024 at 6:14 PM Andrew Sales andrew@andrewsales.com wrote:

Hello,

If I understand the spec for this function[1] correctly, at most one element should be returned for a given ID value:

"If several elements have the same ID value, then E is the one that is first in document order." ("Rules", item 3)

BaseX behaves differently from e.g. Saxon in this respect. The query:

let $doc := document{<foo xml:id='a1'><bar xml:id='a1'/></foo>}

return ( 'Saxon-HE 11.6:', xslt:transform($doc, <xsl:stylesheet xmlns:xsl=" http://www.w3.org/1999/XSL/Transform" xmlns:xs="http://www.w3.org/2001/XMLSchema" exclude-result-prefixes="xs" version="3.0">

<xsl:template match="/">
    <xsl:sequence select="id('a1')"/>
</xsl:template>

</xsl:stylesheet>), 'BaseX 10.7:', $doc/id('a1') )

returns:

Saxon-HE 11.6: <foo xml:id="a1"><bar xml:id="a1"/></foo> BaseX 10.7: <foo xml:id="a1"><bar xml:id="a1"/></foo>

<bar xml:id="a1"/>

i.e. Saxon returns only the first in document order, whereas BaseX returns both of them.

Grateful for your thoughts, Andrew

[1] https://www.w3.org/TR/xpath-functions-31/#func-id