recursive php function: trouble spotting the bug - php

Question

I have a family tree app in laravel, and I want to be able to show an outline view (start with a family from long ago, show its kids, show those kids' families, those families' kids, etc).
So I made this recursive get_descendants function:
public static function get_descendants(Family $family, $results_array, $counter)
{
// start new round with a different temp array, to keep track
$counter++;
$this_array = "array_$counter";
$$this_array = [];
array_push ($$this_array, $family->caption);
$kids = FamilyController::get_kids_of_family($family);
// if family has no kids, return 0;
if (!count($kids))
{
return 0;
}
else // add kids and check for their families
{
foreach ($kids as $kid) {
array_push ($$this_array, $kid->firstname);
// get families made by kid- for each one, call get_descendants
$families_made = FamilyController::get_families_person_made($kid);
foreach ($families_made as $new_family) {
array_push($$this_array, self::get_descendants($new_family, $$this_array, $counter));
}
};
// we've gone through the kids, add this round's array to the general results array
array_push ($results_array, $$this_array);
}
return $results_array;
}
I've confirmed with print statements that the looping through is correct, but there's a problem with the way I'm saving the results. I want to get something like this, where the top family shows once, with children and their families nested:
array:1 [▼
0 => array:4 [▼
0 => "Padme & Anakin"
1 => "Leia"
2 => array:3 [▼
0 => "Leia & Han"
1 => "Kylo Ren"
]
3 => "Luke"
]
]
but I'm getting this (with an extra repeat in the middle):
array:1 [▼
0 => array:4 [▼
0 => "Padme & Anakin"
1 => "Leia"
2 => array:3 [▼
0 => "Padme & Anakin"
1 => "Leia"
2 => array:3 [▼
0 => "Leia & Han"
1 => "Kylo Ren"
]
]
3 => "Luke"
]
]
Can anyone see where my mistake is?

Answer 1

Update: it turns out that it works if I get rid of that final results_array and just use the dynamic one the whole way, like this:
public static function get_descendants(Family $family, $results_array, $counter)
{
// start new round with a different temp array, to keep track
$counter++;
$this_array = "array_$counter";
$$this_array = [];
array_push ($$this_array, $family->caption);
$kids = FamilyController::get_kids_of_family($family);
// if family has no kids, return 0;
if (!count($kids))
{
return 0;
}
else // add kids and check for their families
{
foreach ($kids as $kid) {
array_push ($$this_array, $kid->first);
// get families made by kid- for each one, call get_descendants
$families_made = FamilyController::get_families_person_made($kid);
if (count($families_made))
{
foreach ($families_made as $new_family) {
array_push($$this_array, self::get_descendants($new_family, $$this_array, $counter));
}
}
};
}
return $$this_array;
}

Answer 2

Looks unnecessarily complex, with dynamic arrays, and you keep populating the same array, so that's why Luke appears in the wrong place.
A cleaner solution might be to be very specific about where people are in the array rather than using a dynamic array name. Just a suggestion -
public static function getDescendants(Family $family)
{
$family = [];
$family['name'] = $family->caption;
if ($kids = static::getKidsOfFamily($family)) {
foreach ($kids as $kid) {
$family['children'][] = $kid->firstname;
$subfamilies = static::getFamiliesPersonMade($kid);
foreach ($subfamilies as $subfamily) {
$family['subfamilies'][] = static::getDescendants($subfamily);
}
};
}
return $family;
}
would produce something like
array [
"name" => "Padme & Anakin"
"children" => array [
"Leia",
"Luke"
],
"subfamilies" => array [
array [
"name" => "Leia & Han"
"children" => array [
"Kylo Re"
]
]
]
]