+/**
+ * Handle source_contact_name as a sort parameter.
+ *
+ * This is passed from the activity selector - e.g search results or contact tab.
+ *
+ * It's a non-standard handling but this api already handles variations on handling source_contact
+ * as a filter & as a field so it's in keeping with that. Source contact has a one-one relationship
+ * with activity table.
+ *
+ * Test coverage in CRM_Activity_BAO_ActivtiyTest::testGetActivitiesforContactSummaryWithSortOptions
+ *
+ * @param array $params
+ * @param array $options
+ * @param CRM_Utils_SQL_Select $sql
+ */
+function _civicrm_activity_get_handleSourceContactNameOrderBy(&$params, &$options, $sql) {
+ $sourceContactID = CRM_Core_PseudoConstant::getKey('CRM_Activity_BAO_ActivityContact', 'record_type_id', 'Activity Source');
+ if (!empty($options['sort'])
+ && in_array($options['sort'], [
+ 'source_contact_name',
+ 'source_contact_name desc',
+ 'source_contact_name asc',
+ ])) {
+ $order = substr($options['sort'], -4) === 'desc' ? 'desc' : 'asc';
+ $sql->join(
+ 'source_contact',
+ "LEFT JOIN
+ civicrm_activity_contact ac ON (ac.activity_id = a.id AND record_type_id = #sourceContactID)
+ LEFT JOIN civicrm_contact c ON c.id = ac.contact_id",
+ ['sourceContactID' => $sourceContactID]
+ );
+ $sql->orderBy("c.display_name $order");
+ unset($options['sort'], $params['options']['sort']);
+ }
+}
+