在foreach中使用kohana orm find_all（）的奇怪行为

I'm a bit irritated why the second Code throws an Exception and the first not. self::ID_FALLBACK is 1, There are 2 or more Rows in Sections with id 1, 2...; all with Sectiongroup_id = 1

There is one Row in Sectiongroup with id 1

This works without any Problems:

public static function getSections(){
    // select groups with sections
    foreach(ORM::factory('Sectiongroup')->find_all() as $grp){
        $s = $grp->sections->where('id', '>', self::ID_FALLBACK)->find_all()->as_array('id', 'name');
        count($s) && $sections[$grp->name] = $s;
    }
    return $sections;
}

Next throws: Cannot use object of type Model_Sectiongroup as array in Line count($s) && $section..

public static function getSections(){
    // select groups with sections
    $sections = ORM::factory('Sectiongroup');
    foreach($sections->find_all() as $grp){
        $s = $grp->sections->where('id', '>', self::ID_FALLBACK)->find_all()->as_array('id', 'name');
        count($s) && $sections[$grp->name] = $s;
    }
    return $sections;
}

Same error with 2 rows in Sectiongroup what should be an array now:

public static function getSections(){
    // select userdefined groups with sections
    $sections = ORM::factory('Sectiongroup');
    foreach($sections->find_all()->as_array() as $grp){
        $s = $grp->sections->where('id', '>', self::ID_FALLBACK)->find_all()->as_array('id', 'name');
        count($s) && $sections[$grp->name] = $s;
    }
    return $sections;
}

Whats that for a strange behavior?

In your first (working) example, you never explicitly define the $sections array, and when you first write $sections[$grp->name] = $s, PHP creates the $sections array for you.

On your last two examples, you explicitly declare $sections to the return value of ORM::factory(), more specifically, an object subclass of ORM with which you cannot use the array subscript ([]) notation with.