option to force xsd schema check for required field

[wangf1122]

This feature and extra param in the render-element function gives option for the sub schema to either force xsd check for required field or not.

[josegar74]

I would rename it to forceParentElementXsdSchemaCheck as the XSD is checked independently of this flag in https://github.com/geonetwork/core-geonetwork/pull/8294/files#diff-dd05931fe2e9562f24fd5ced36ad129469606fad5f2aac2cdc97da357e5d99bcR121

Another more radical it can be just rely on the labels.xml file condition element, but probably will be confusing. It seems more suitable to implement this in a new version, not for 4.4 or 4.2

<xsl:variable name="elementCondition" select="gn-fn-metadata:getLabel($schema, name(), 
     $labels, name(..),$isoType, $xpath)/condition" />

<xsl:variable name="isRequired" as="xs:boolean">
    <xsl:choose>
        <xsl:when test="$elementCondition = 'mandatory'">
            <xsl:value-of select="true()"/>
        </xsl:when>
        <xsl:otherwise>
            <xsl:value-of select="false()"/>
        </xsl:otherwise>
    </xsl:choose>
</xsl:variable>

[ianwallen]

What about using the element condition to and a new option called "optional" that would override the XSD?
Something like the following? If someone specify the condition as mandatory or optional then it could override the XSD.
It seems like this would be less radical and would cause less impact.

<xsl:variable name="elementCondition" select="gn-fn-metadata:getLabel($schema, name(),
$labels, name(..),$isoType, $xpath)/condition" />

<xsl:variable name="isRequired" as="xs:boolean">
    <xsl:choose>
        <xsl:when test="$elementCondition = 'mandatory'">
            <xsl:value-of select="true()"/>
        </xsl:when>
        <xsl:when test="$elementCondition = 'optional'">
            <xsl:value-of select="false()"/>
        </xsl:when>
        // If not defined then set it to empty value to use default from schema definition.
        <xsl:otherwise>
            <xsl:value-of select="''"/>
        </xsl:otherwise>
    </xsl:choose>
</xsl:variable>

Then we would just add the condition of optional?
<condition>optional</condition>