[BUG]: Wrong return type hint for Phalcon\Mvc\Model::average

[sergeyklay]

Current return type hint of the Phalcon\Mvc\Model::average implies that method must return a float value. But this method MAY return am Phalcon\Mvc\Model\ResultsetInterface instance for for when the GROUP condition is used:

cphalcon/phalcon/Mvc/Model.zep

Lines 702 to 705 in 45ee3a4

	public static function average(var parameters = null) -> float
	{
	return self::_groupResult("AVG", "average", parameters);
	}

For example:

use Phalcon\Di;
use Phalcon\Di\FactoryDefault;
use Phalcon\Db\Adapter\PdoFactory;
use Phalcon\Mvc\Model;

$options = ['dbname' => '/tmp/test.sqlite'];

Di::reset();

$container = new FactoryDefault();
Di::setDefault($container);

$container->setShared(
    'db',
    (new PdoFactory())->newInstance('sqlite', $options)
);

class Invoices extends Model {
    public $inv_id;
    public $inv_cst_id;
    public $inv_status_flag;
    public $inv_title;
    public $inv_total;
    public $inv_created_at;

    public function initialize()
    {
        $this->setSource('co_invoices');
    }
}

// All is OK
var_dump(Invoices::average(['column' => 'inv_id'])); 

// Fatal Error
var_dump(Invoices::average(         
    [
        'column' => 'inv_id',
        'group' => 'inv_cst_id'
    ]
));

This leads to a fatal error:

PHP Fatal error:
Return value of Phalcon\Mvc\Model::average()
must be of the type float, object returned

[sergeyklay]

Fixed in 4.0.x branch