TYPO3 Core

the documentation for the new special-HMENU "categories" states that the id's of the selected categories should be accsessible as a getText/stdWrap with the field "_categories". see [[http://docs.typo3.org/typo3cms/TyposcriptReference/latest/ContentObjects/Hmenu/#hmenu-special-categories]]

however, this is not the case:
the "_categories" are set in collectPages() function of CategoryMenuUtility.php but they never make it to Typoscript.

we've tracked down the issue to the modifyDBRow(&$row, $table) function in:
typo3/sysext/core/Classes/Resource/Service/FrontendContentAdapterService.php
where the _categories entry gets removed form the array.

the modifyDBRow function is called in the start($data, $table = '') function in:
/typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php

here's the relevant snippet of ContentObjectRenderer.php ~#523:

public function start($data, $table = '') {
    global $TYPO3_CONF_VARS;
    var_dump($data); //_categories are set
    if (is_array($data) && !empty($data) && !empty($table)) {
        \TYPO3\CMS\Core\Resource\Service\FrontendContentAdapterService::modifyDBRow($data, $table);
    }
    $this->data = $data;
    var_dump($this->data); //_categories are MISSING