Some transformers create execution contexts that are not cleared after execution

• User impact:

  High
• Configuration:

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  <?xml version="1.0" encoding="UTF-8"?>
  <mule xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:http="http://www.mulesoft.org/schema/mule/http"
  xmlns:file="http://www.mulesoft.org/schema/mule/file"
  xmlns:script="http://www.mulesoft.org/schema/mule/scripting"
  xmlns:mulexml="http://www.mulesoft.org/schema/mule/xml"
  xsi:schemaLocation="
  http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/3.1/mule.xsd
  http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/3.1/mule-http.xsd
  http://www.mulesoft.org/schema/mule/file http://www.mulesoft.org/schema/mule/file/3.1/mule-file.xsd
  http://www.mulesoft.org/schema/mule/xml http://www.mulesoft.org/schema/mule/xml/3.1/mule-xml.xsd
  http://www.mulesoft.org/schema/mule/scripting http://www.mulesoft.org/schema/mule/scripting/3.1/mule-scripting.xsd">
  <file:connector name="X" autoDelete="true" streaming="false"/>
  <flow name="FSBME012RUD-main">
  <file:inbound-endpoint path="/tmp/test" pollingFrequency="1000"/>
  <object-to-string-transformer/>
  <script:transformer>
  <script:script engine="groovy">
  <script:text>
  operatorRecordIds = [:]
  operatorRecordCounts = [:]
  message.setSessionProperty("operatorRecordIds", operatorRecordIds)
  message.setSessionProperty("operatorRecordCounts", operatorRecordCounts)
  return payload
  </script:text>
  </script:script>
  </script:transformer>
  <mulexml:xslt-transformer name="xslt">
  <mulexml:xslt-text>
  <xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="xml"/>
  <xsl:param name="title"/>
  <xsl:param name="rating"/>
  <xsl:param name="payload"/>
  <xsl:template match="catalog">
  <xsl:element name="cd-listings">
  <xsl:attribute name="title">
  <xsl:value-of select="$title"/>
  </xsl:attribute>
  <xsl:attribute name="rating">
  <xsl:value-of select="$rating"/>
  </xsl:attribute>
  <xsl:value-of select="$payload"/>
  <xsl:apply-templates/>
  </xsl:element>
  </xsl:template>
  <xsl:template match="cd">
  <xsl:element name="cd-title">
  <xsl:value-of select="title"/>
  </xsl:element>
  </xsl:template>
  </xsl:stylesheet>
  </mulexml:xslt-text>
  <mulexml:context-property key="title" value="#[string:foo]"/>
  <mulexml:context-property key="rating" value="#[string:bar]"/>
  <mulexml:context-property key="payload" value="#[payload]"/>
  </mulexml:xslt-transformer>

  <file:outbound-endpoint path="/tmp/out"/>
  </flow>
  </mule>

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  <?xml version="1.0" encoding="UTF-8"?> <mule xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:http="http://www.mulesoft.org/schema/mule/http" xmlns:file="http://www.mulesoft.org/schema/mule/file" xmlns:script="http://www.mulesoft.org/schema/mule/scripting" xmlns:mulexml="http://www.mulesoft.org/schema/mule/xml" xsi:schemaLocation=" http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/3.1/mule.xsd http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/3.1/mule-http.xsd http://www.mulesoft.org/schema/mule/file http://www.mulesoft.org/schema/mule/file/3.1/mule-file.xsd http://www.mulesoft.org/schema/mule/xml http://www.mulesoft.org/schema/mule/xml/3.1/mule-xml.xsd http://www.mulesoft.org/schema/mule/scripting http://www.mulesoft.org/schema/mule/scripting/3.1/mule-scripting.xsd"> <file:connector name="X" autoDelete="true" streaming="false"/> <flow name="FSBME012RUD-main"> <file:inbound-endpoint path="/tmp/test" pollingFrequency="1000"/> <object-to-string-transformer/> <script:transformer> <script:script engine="groovy"> <script:text> operatorRecordIds = [:] operatorRecordCounts = [:] message.setSessionProperty("operatorRecordIds", operatorRecordIds) message.setSessionProperty("operatorRecordCounts", operatorRecordCounts) return payload </script:text> </script:script> </script:transformer> <mulexml:xslt-transformer name="xslt"> <mulexml:xslt-text> <xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output method="xml"/> <xsl:param name="title"/> <xsl:param name="rating"/> <xsl:param name="payload"/> <xsl:template match="catalog"> <xsl:element name="cd-listings"> <xsl:attribute name="title"> <xsl:value-of select="$title"/> </xsl:attribute> <xsl:attribute name="rating"> <xsl:value-of select="$rating"/> </xsl:attribute> <xsl:value-of select="$payload"/> <xsl:apply-templates/> </xsl:element> </xsl:template> <xsl:template match="cd"> <xsl:element name="cd-title"> <xsl:value-of select="title"/> </xsl:element> </xsl:template> </xsl:stylesheet> </mulexml:xslt-text> <mulexml:context-property key="title" value="#[string:foo]"/> <mulexml:context-property key="rating" value="#[string:bar]"/> <mulexml:context-property key="payload" value="#[payload]"/> </mulexml:xslt-transformer> <file:outbound-endpoint path="/tmp/out"/> </flow> </mule>
• Similar Issues:

  None

Some transformers (xslt and scripting being two of them) create execution contexts. These contexts are not cleared after the execution of the transformer, so information is kept in memory until the next message arrives.
Customers with a large number of transformers and large messages report that Mule creates objects that are never garbage collected after a message has been processed.
Steps to reproduce:
1) Run the attached configuration.
2) Connect a profiler
3) Copy the attached XML file in the "/tmp/test" folder
4) Force a garbage collection
5) Look for the retained size of GroovyScriptEngineImpl and XsltTransformer
(both objects still retain the message that has passed through)