eZ\Publish\Core\Persistence\Legacy\Content\FieldHandler::updateCopiedField PHP Method

    protected function updateCopiedField(Field $field, Field $updateField, Field $originalField, Content $content)
    {
        $field->versionNo = $content->versionInfo->versionNo;
        $field->value = clone $updateField->value;
        $this->contentGateway->updateField($field, $this->mapper->convertToStorageValue($field));
        // If the storage handler returns true, it means that $field value has been modified
        // So we need to update it in order to store those modifications
        // Field converter is called once again via the Mapper
        if ($this->storageHandler->copyFieldData($content->versionInfo, $field, $originalField) === true) {
            $this->contentGateway->updateField($field, $this->mapper->convertToStorageValue($field));
        }
    }