lib/Query/Common/SortClauseVisitor/Field.php
protected function getSortFieldName(
        SortClause $sortClause,
        $contentTypeIdentifier,
        $fieldDefinitionIdentifier
    ) {
        return $this->fieldNameResolver->getSortFieldName(
            $sortClause,
            $contentTypeIdentifier,
            $fieldDefinitionIdentifier
        );
    }
protected function getSortFieldName(
        SortClause $sortClause,
        $contentTypeIdentifier,
        $fieldDefinitionIdentifier
    ) {
        return $this->fieldNameResolver->getSortFieldName(
            $sortClause,
            $contentTypeIdentifier,
            $fieldDefinitionIdentifier
        );
    }
Get sort field name.

@param \eZ\Publish\API\Repository\Values\Content\Query\SortClause $sortClause
@param string $contentTypeIdentifier
@param string $fieldDefinitionIdentifier

@return array