Marklogic xdmp:node-insert-child adds empty xmlns

When I run the following code, I end up with an empty xmlns in the node that was added:

declare namespace myns = "http://hello.com/myns";

xdmp:node-insert-child(
    fn:doc($file)/myns:results,
    <event ts="{fn:current-dateTime()}">Removed</event>)

Result:

<?xml version="1.0" encoding="UTF-8"?>
<results xmlns="http://hello.com/myns">
    <event ts="2018-09-21T15:23:23">Created</event>
    <event ts="2018-09-21T15:23:28" xmlns="">Removed</event>
</results>

This causes a log of issues, any idea why this happens?

Solution

This is because the Created event is already in the http://hello.com/myns namespace. But the Removed event is not in any namespace, so that's why you're seeing xmlns="" in the XML, which designates it a no-namespace element.

If you want them all in the same namespace, you can prefix the event you are inserting or add a default namespace declaration:

<myns:event ts="...">
<event xmlns="http://hello.com/myns" ts="...">