php - is_null function not working properly in my if statement -

i have if statement detects if user logged in , belongs division. quite simple.

there permissions.php class, returns user object if logged in or null.

protected $user = null; ... public static function instance() {   if(!self::$instance) {     self::$instance = new permissions();   }   return self::$instance; } ... public function get_user() {   return $this->user; } 

there user.php class, has functions return division in:

public function is_manager() {   return $this->is_manager; } 

so should able following:

if(permissions::instance()->get_user()->is_manager()) 

but of course might throw warning null objects, thought following:

if( ( ! is_null( permissions::instance()->get_user() ) ) &&     ( permissions::instance()->get_user()->is_manager() )) 

which should check null , if not, should evaluate other half of if statement, php reason, evaluates of , still complains null object (when user not logged in).

so broke if statement nested if statement, , php still complained null object, led me believe is_null method wasn't working expected.

this worked in end:

if (permissions::instance()->get_user() != null) {   if(permissions::instance()->get_user()->is_manager()){     ...   } } 

my question is, why did code is_null function not work?

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upon further testing, of great comments, turns out get_user() wasn't returning null, (bool)false (from var_dump). why strange behaviour exhibited? class sets null @ top , function returns variable false?

because != not check type (null type) , get_user() returned empty string or false (see php type comparison table).

check output of:

var_dump(permissions::instance()->get_user());