FHIR Chat · Extension content in Snapshot?

Stream: implementers

Topic: Extension content in Snapshot?

Ardon Toonstra (Dec 06 2021 at 09:11):

Should the content of extensions be included in the snapshot of the host profile?

Patrick Werner (Dec 06 2021 at 10:06):

I would expect them to contain the extension content.

Ardon Toonstra (Dec 06 2021 at 10:56):

It seems that the snapshot generators of JAVA and .NET only include the root concept details into the host profiles snapshot. It leaves out the .value[x] constraints like a binding. (Checked the JAVA stuff by looking at the snapshots of the US Core IG)

Makes me wonder about this part of the spec: "a StructureDefinition can also carry a "snapshot" - a fully calculated form of the structure that is not dependent on any other structure." https://hl7.org/FHIR/profiling.html#snapshot

Grahame Grieve (Dec 06 2021 at 11:07):

where what? Can you give an example?

Ardon Toonstra (Dec 06 2021 at 11:47):

us-core-patient profile includes the us-core-birthsex extension like this in the diff:

    <element id="Patient.extension:birthsex">
      <path value="Patient.extension"/>
      <sliceName value="birthsex"/>
      <min value="0"/>
      <max value="1"/>
      <type>
        <code value="Extension"/>
        <profile value="http://hl7.org/fhir/us/core/StructureDefinition/us-core-birthsex"/>
      </type>
      <mustSupport value="false"/>
      <mapping>
        <identity value="argonaut-dq-dstu2"/>
        <map value="Patient.extension"/>
      </mapping>
    </element>

Resulting in this snapshot:

 <element id="Patient.extension:birthsex">
      <path value="Patient.extension"/>
      <sliceName value="birthsex"/>
      <short value="Extension"/>
      <definition value="A code classifying the person&#39;s sex assigned at birth  as specified by the [Office of the National Coordinator for Health IT (ONC)](https://www.healthit.gov/newsroom/about-onc)."/>
      <comment value="The codes required are intended to present birth sex (i.e., the sex recorded on the patient&#x2019;s birth certificate) and not gender identity or reassigned sex."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="DomainResource.extension"/>
        <min value="0"/>
        <max value="*"/>
      </base>
      <type>
        <code value="Extension"/>
        <profile value="http://hl7.org/fhir/us/core/StructureDefinition/us-core-birthsex"/>
      </type>
      <condition value="ele-1"/>
      <constraint>
        <key value="ele-1"/>
        <severity value="error"/>
        <human value="All FHIR elements must have a @value or children"/>
        <expression value="hasValue() or (children().count() &gt; id.count())"/>
        <xpath value="@value|f:*|h:div"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/>
      </constraint>
      <constraint>
        <key value="ext-1"/>
        <severity value="error"/>
        <human value="Must have either extensions or value[x], not both"/>
        <expression value="extension.exists() != value.exists()"/>
        <xpath value="exists(f:extension)!=exists(f:*[starts-with(local-name(.), &#39;value&#39;)])"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Extension"/>
      </constraint>
      <mustSupport value="false"/>
      <isModifier value="false"/>
      <mapping>
        <identity value="rim"/>
        <map value="player[classCode=PSN|ANM and determinerCode=INSTANCE]/administrativeGender"/>
      </mapping>
      <mapping>
        <identity value="iso11179"/>
        <map value=".patient.administrativeGenderCode"/>
      </mapping>
      <mapping>
        <identity value="argonaut-dq-dstu2"/>
        <map value="Patient.extension"/>
      </mapping>
    </element>

I would expect that also the following would be included in the snapshot:

   <element id="Extension.url">
      <path value="Extension.url"/>
      <fixedUri value="http://hl7.org/fhir/us/core/StructureDefinition/us-core-birthsex"/>
    </element>
    <element id="Extension.valueCode">
      <path value="Extension.valueCode"/>
      <min value="1"/>
      <max value="1"/>
      <type>
        <code value="code"/>
      </type>
      <binding>
        <strength value="required"/>
        <description value="Code for sex assigned at birth"/>
        <valueSet value="http://hl7.org/fhir/us/core/ValueSet/birthsex"/>
      </binding>
    </element>