Remove XML hierarchy elements with the same name using XSLT?

Question

An XML response I am getting has the same named elements next to each other in the response which is causing me issues, I need to remove this recurring element using XSLT 1.0. The element in question in the response is <RoundIncidents> . I have had a look through other questions but can't find what I need to transform the response to the correct format.

XML Response with Recurring Element

<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   <soap:Body>
      <GetSiteIncidentsResponse xmlns="http://webservices.whitespacews.com/">
         <GetSiteIncidentsResult>
            <ErrorCode>0</ErrorCode>
            <ErrorDescription>Success</ErrorDescription>
            <SuccessFlag>true</SuccessFlag>
            <RoundIncidents>
               <RoundIncidents>
                  <ExtensionData />
                  <AccountSiteID>0</AccountSiteID>
                  <RoundIncidentID>8</RoundIncidentID>
                  <RoundRoundAreaServiceScheduleID>157</RoundRoundAreaServiceScheduleID>
                  <RoundCode>REC1</RoundCode>
                  <ScheduleName>MonFort2</ScheduleName>
                  <ServiceName>Recycling Collection Service</ServiceName>
                  <RoundAreaName>REC1 - MonFort2</RoundAreaName>
                  <RoundIncidentDate>2019-04-08T16:12:10</RoundIncidentDate>
                  <RoundIncidentNotes>Road Closed</RoundIncidentNotes>
                  <RoundIncidentCreatedByID>129</RoundIncidentCreatedByID>
                  <RoundIncidentCreatedDate>2019-04-08T16:12:26.493</RoundIncidentCreatedDate>
               </RoundIncidents>
            </RoundIncidents>
         </GetSiteIncidentsResult>
      </GetSiteIncidentsResponse>
   </soap:Body>
</soap:Envelope>

Desired Outcome following XSLT Transformation

<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   <soap:Body>
      <GetSiteIncidentsResponse xmlns="http://webservices.whitespacews.com/">
         <GetSiteIncidentsResult>
            <ErrorCode>0</ErrorCode>
            <ErrorDescription>Success</ErrorDescription>
            <SuccessFlag>true</SuccessFlag>            
               <RoundIncidents>
                  <ExtensionData />
                  <AccountSiteID>0</AccountSiteID>
                  <RoundIncidentID>8</RoundIncidentID>
                  <RoundRoundAreaServiceScheduleID>157</RoundRoundAreaServiceScheduleID>
                  <RoundCode>REC1</RoundCode>
                  <ScheduleName>MonFort2</ScheduleName>
                  <ServiceName>Recycling Collection Service</ServiceName>
                  <RoundAreaName>REC1 - MonFort2</RoundAreaName>
                  <RoundIncidentDate>2019-04-08T16:12:10</RoundIncidentDate>
                  <RoundIncidentNotes>Road Closed</RoundIncidentNotes>
                  <RoundIncidentCreatedByID>129</RoundIncidentCreatedByID>
                  <RoundIncidentCreatedDate>2019-04-08T16:12:26.493</RoundIncidentCreatedDate>
               </RoundIncidents>            
         </GetSiteIncidentsResult>
      </GetSiteIncidentsResponse>
   </soap:Body>
</soap:Envelope>

kjhughes kjhughes · Accepted Answer · 2019-04-11T14:12:30

Removing Child

Add a template to the identity transform that matches child elements where the parent and child have the same QName, and the child is bypassed:

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

  <xsl:template match="@*|node()">
    <xsl:copy>
      <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
  </xsl:template>

  <xsl:template match="*[name() = name(..)]">
    <xsl:apply-templates select="node()"/>
  </xsl:template>

</xsl:stylesheet>

Demo on Martin Honnen's handy XSLT Fiddle.

Note that the above lexically compares QNames, which may include namespace prefixes. To compare names properly (semantically), check the namespace URIs:

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

  <xsl:template match="@*|node()">
    <xsl:copy>
      <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
  </xsl:template>

  <xsl:template match="*[    local-name() = local-name(..) 
                         and namespace-uri() = namespace-uri(..)]">
    <xsl:apply-templates select="node()"/>
  </xsl:template>

</xsl:stylesheet>

Updated demo.

Removing Parent

Per OP's updated request, here's how to remove the parent element when there's a child element named the same. In choosing which approach to take, consider that in general a child can only have one parent, but a parent can have multiple children.

Simple QName check:

<xsl:template match="*[*[name() = name(..)]]">
  <xsl:apply-templates select="node()"/>
</xsl:template>

Full Namespace URI check:

<xsl:template match="*[*[    local-name() = local-name(..) 
                         and namespace-uri() = namespace-uri(..)]]">
  <xsl:apply-templates select="node()"/>
</xsl:template>

Credit: Thanks to @Alejandro and @michael.hor257k for helpful corrections and improvements.