[11.x] Replace while loop with array_walk

[seriquynh]

Inside Foundation\Application and Support\ServiceProvider classes, there is code that executes callbacks sequentially like this:

protected function fireAppCallbacks(array &$callbacks)
{
    $index = 0;

    while ($index < count($callbacks)) { // count function is called on every callback.
        $callbacks[$index]($this);

        $index++;
    }
}

The while loop can be replaced with array_walk like code below. Then, no need to initialize and increase $index variable, unnecessary count calls are removed.

protected function fireAppCallbacks(array &$callbacks)
{
    array_walk(
        $callbacks, fn($callback) => $callback($this)
    );
}

Plus: I add tests to ensure booting/booted callbacks are executed sequentially.

[dennisprudlo]

Isn't it possible that one of those callbacks will add more callbacks to the list? And if so, does array_walk consider this?

[henzeb]

Isn't it possible that one of those callbacks will add more callbacks to the list? And if so, does array_walk consider this?

Just so you know: yes it does. But a while loop is slightly bit faster...

[seriquynh]

@dennisprudlo I think we can use array_map but do nothing with it's returned result.

@henzeb If while loop is still used this case, we shouldn't call count function inside condition section "while ($index < count($callbacks))", should we?

For me, Laravel code is unpredictable, decisions are sometimes randomly accepted, a bit inconsistent.