Bug #73872 [Opn->Csd]: Static method variable state depends on file include

Edit report at https://bugs.php.net/bug.php?id=73872&edit=1 ID: 73872 Updated by: nikic@php.net Reported by: sc at shpock dot com Summary: Static method variable state depends on file include -Status: Open +Status: Closed Type: Bug Package: Class/Object related Operating System: Linux PHP Version: 7.0.14 -Assigned To: +Assigned To: nikic Block user comment: N Private report: N New Comment: This issue has been fixed in PHP 8.1 with https://github.com/php/php-src/commit/5d160e309ed207e618d49029e51c9c2dc2c5e61c. The reason why the include makes a difference is that without the include, the CihldClass is early bound, which means that it is actually registered before the call to $parent->getSomething(). After the aforementioned fix, the call to getSomething() no longer influences the behavior. Previous Comments: ------------------------------------------------------------------------ [2017-01-05 13:34:18] sc at shpock dot com Description: ------------ Setup: a parent class which defines a static variable in a method. The static variable is initialized with NULL and set to some value on the first method call. Then, a child class calls the same (inherited) method. If the child class definition is in the same file as the parent class definition, this works as expected. However, if the child class definition is loaded from a separate file and this file is loaded after(!) the first call to the method which sets the static variable, the static variable seems to be "shared" between both classes. I'm really curious about an explanation in case this is not a bug because i would like to understand the concept. Thank you! Test script: --------------- class ParentClass { protected $something = 'parent'; public function getSomething() { static $cache; return $cache !== null ? $cache : $cache = $this->something; } } $parent = new ParentClass(); var_dump($parent->getSomething()); // expected: 'parent'; returned: 'parent' include 'child.php'; # content of child.php: //class ChildClass extends ParentClass //{ // protected $something = 'child'; //} $child = new ChildClass(); var_dump($child->getSomething()); // expected 'child'; returned 'parent' ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=73872&edit=1