Filtering by Single Parent ID Also Returns Grandchildren

Problem/Motivation

Not sure if this is the expected behavior, but when filtering by a single parent id, it will return children and grandchildren.

Steps to reproduce

Example menu

• Menu Item 1
  • Menu Item 2
  • Menu Item 3
  • Menu Item 4
    • Menu Item 5

Filtering example

?filter[parent]=menu_link_content:menu-item-1

This will return 4 results, including “Menu Item 5”, which is not a direct child of “Menu Item 1”, but a grandchild. My expectation was that if you’re filtering by a single parent id, it would only return direct children, not grandchildren ?

You can work around this by also adding a max_depth of 1 to force only getting direct children:

?filter[parent]=menu_link_content:menu-item-1&filter[max_depth]=1

Proposed resolution

Should the default behavior be a max depth of 1 when filtering by a single parent id ? If the logic is give me all menu items where parent id = menu_link_content:menu-item-1, I wouldn't expect grandchild menu items to also be included. This default could be added, if we made the following change to applyFiltersToParams

if (!empty($filter['parent'])) {
  $parameters->setRoot($filter['parent']);
  $parameters->setMaxDepth(1);
  $parameters->excludeRoot();
}