Description:
------------
Array with first element null is true

Test script:
---------------
$arr = [ 0 => null];
if ($arr) {
    echo 'is true';
} else {
    echo 'is false';
}

//TEST 2 
$arr = explode(',', null);
if ($arr) {
    echo 'is true';
} else {
    echo 'is false';
}

Expected result:
----------------
is false

Actual result:
--------------
is true