Config Transform, Unrecognized XML Namespace After Transformation

Question

One of our config files is being transformed oddly.

Base Config

<?xml version="1.0"?>
<configuration >

</configuration>

Release Config (as it is in the project, truncated for brevity)

<?xml version="1.0"?>
<configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform" xmlns:role="http://www.sitecore.net/xmlconfig/role/" xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore xdt:Transform="Insert">
    <contentSearch>
      <configuration>
        <indexes>
          <index id="sitecore_web_index">
            <param desc="core" patch:instead="param[@desc='core']">#{IndexEnvironment}#_web_index</param>
          </index>
        </indexes>
        <indexes role:require="Standalone or ContentManagement">
          <index id="sitecore_master_index">
            <param desc="core" patch:instead="param[@desc='core']">#{IndexEnvironment}#_master_index</param>
          </index>

After a build is run, the output of the final config looks very strange:

Post build

<?xml version="1.0"?>
<configuration>
    <sitecore>
        <contentSearch>
            <configuration>
                <indexes>
                    <index id="sitecore_web_index">
                        <param desc="core" d7p1:instead="param[@desc='core']" xmlns:d7p1="http://www.sitecore.net/xmlconfig/">ASHQA_web_index</param>
                    </index>
                </indexes>
                <indexes d5p1:require="Standalone or ContentManagement" xmlns:d5p1="http://www.sitecore.net/xmlconfig/role/">
                    <index id="sitecore_master_index">
                        <param desc="core" d7p1:instead="param[@desc='core']" xmlns:d7p1="http://www.sitecore.net/xmlconfig/">ASHQA_master_index</param>
                    </index>

Notice how the patch and role definitions are changed to d7p1 and d5p1 respectively.

While this is valid XML, it is causing issues in our application which parses the XML and looks for the proper terms of patch and role.

Answer 1

TL;DR

Any namespaces required in a transformed config, need to be defined in the base config.

Base Config Updates

<?xml version="1.0"?>
<configuration xmlns:role="http://www.sitecore.net/xmlconfig/role/" xmlns:patch="http://www.sitecore.net/xmlconfig/">

</configuration>

Even though the base config does not rely on these namespaces, they do not carry over properly if they are not included. This also cleans up the output of the resulting config as expected:

<?xml version="1.0"?>
<configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform" xmlns:role="http://www.sitecore.net/xmlconfig/role/" xmlns:patch="http://www.sitecore.net/xmlconfig/">
    <sitecore>
        <contentSearch>
            <configuration>
                <indexes>
                    <index id="sitecore_web_index">
                        <param desc="core" patch:instead="param[@desc='core']">#{IndexEnvironment}#_web_index</param>
                    </index>
                </indexes>
                <indexes role:require="Standalone or ContentManagement">
                    <index id="sitecore_master_index">
                        <param desc="core" patch:instead="param[@desc='core']">#{IndexEnvironment}#_master_index</param>
                    </index>