note 124383 added to language.references.pass

Within a class, passing array elements by reference which don't exist are added to the array as null. Compared to a normal function, this changes the behavior of the function from throwing an error to creating a new (null) entry in the referenced array with a new key. <?php class foo { public $arr = ['a' => 'apple', 'b' => 'banana']; public function normalFunction($key) { return $this->arr[$key]; } public function &referenceReturningFunction($key) { return $this->arr[$key]; } } $bar = new foo(); $var = $bar->normalFunction('beer'); //Notice Error. Undefined index beer $var = &$bar->referenceReturningFunction('beer'); // No error. The value of $bar is now null var_dump($bar->arr); /** [ "a" => "apple", "b" => "banana", "beer" => null, ], */ ?> This is in no way a "bug" - the framework is performing as designed, but it took careful thought to figure out what was going on. PHP7.3 ---- Server IP: 208.43.231.9 Probable Submitter: 82.199.157.54 (proxied: 23.125.164.160) ---- Manual Page -- http://php.net/manual/en/language.references.pass.php Edit -- https://master.php.net/note/edit/124383 Del: integrated -- https://master.php.net/note/delete/124383/integrated Del: useless -- https://master.php.net/note/delete/124383/useless Del: bad code -- https://master.php.net/note/delete/124383/bad+code Del: spam -- https://master.php.net/note/delete/124383/spam Del: non-english -- https://master.php.net/note/delete/124383/non-english Del: in docs -- https://master.php.net/note/delete/124383/in+docs Del: other reasons-- https://master.php.net/note/delete/124383 Reject -- https://master.php.net/note/reject/124383 Search -- https://master.php.net/manage/user-notes.php