Yii2: bug with ArrayHelper::filter($array, $filters)

[rikcage]

Hi i found a bug in
public static function filter ($ array, $ filters)
yii2 / framework / helpers / BaseArrayHelper.php file
line 947 if ($ filter [0] === '!')
if $ filters is one dimensional array i see

PHP Notice - yii \ base \ ErrorException

Trying to access array offset on value of type int
1.in /var/www/test_dev/vendor/yiisoft/yii2/helpers/BaseArrayHelper.phpat line 947

 * @return array Filtered array
 * @since 2.0.9
 * /
public static function filter ($ array, $ filters)
{
    $ result = [];
    $ excludeFilters = [];

    foreach ($ filters as $ filter) {
        if ($ filter [0] === '!') {
            $ excludeFilters [] = substr ($ filter, 1);
            continue;
        }

        $ nodeValue = $ array; // set $ array as root node
        $ keys = explode ('.', $ filter);
        foreach ($ keys as $ key) {
            if (! array_key_exists ($ key, $ nodeValue)) {
                continue 2; // Jump to next filter

In older versions it worked like this
$ array:

Array
(
    [0] => #
    [1] => Action Column
    [2] => User
    [3] => Subject
    [4] => Is Active
    [5] => Created At
    [6] => Updated At
)

$ filters:

Array
(
    [0] => 0
    [1] => 1
    [2] => 3
    [3] => 2
    [4] => 6
    [5] => 5
)

$ result:

Array
(
    [0] => #
    [1] => Action Column
    [3] => Subject
    [2] => User
    [6] => Updated At
    [5] => Created At
    [4] => Is Active
)

It was possible to use ArrayHelper :: filter to display the array in the desired order.
I fixed it like this

- 947 if ($ filter [0] === '!') {
+ 947 if (is_array ($ filter) && $ filter [0] === '!') {

Maybe it should be included this in the repository?

Additional info

| Q | A
| ---------------- | ---
| Yii version | 2.0.39.2
| PHP version | 7.4.3
| Operating system | Ubuntu 20.04

[samdark]

@rikcage do you have time for a pull request with a unit test and the fix?

[zavg]

It seems that @rikcage uses integer values in the filters argument, but they are expected to be strings.

[bizley]

I think this is a misunderstanding of the cause of this error. $filters must be a flat array (and it should be checked BTW). The problem here is the same as in #18426 - the check for the first character being exclamation mark is done accessing the string as an array.

[bizley]

I'll fix this together with all other places having similar solution.

[zavg]

@bizley But the notice from bug report says 'Trying to access array offset on value of type int', and the flat array of integers is passed as an argument.

[bizley]

Hmm, right. The change introduced in https://github.com/yiisoft/yii2/commit/b794d76056ac2fe7426018f5400e9921a4952a55#diff-e6a3dd2628f9c50a496966ef3ba411cae921504c003153c65d723292ed1a3a2c rendered using integer keys here impossible. I'll try to re-enable it.