Req #77537 [Com]: Unexpected behavior, when using static in constructor

Edit report at https://bugs.php.net/bug.php?id=77537&edit=1 ID: 77537 Comment by: dirk dot gerigk at atraveo dot com Reported by: dirk dot gerigk at atraveo dot com Summary: Unexpected behavior, when using static in constructor Status: Re-Opened Type: Feature/Change Request Package: Class/Object related Operating System: Windows 10 PHP Version: 7.2.14 Block user comment: N Private report: N New Comment: I have tested in another way class A { public function test(){ static $test = 0; print (++$test); } public function __construct(){ $this->test(); } } class B extends A { public function __construct(){ parent::__construct(); } } class C extends A {} $a = new A; $a->__construct(); $b = new B; $b->__construct(); $c = new C; $c->__construct(); and the result is 121212 So, for now i will keep in mind: * dont mess with the constuctor of a class * do not use static variables in a constructor Thanks for the time and work Previous Comments: ------------------------------------------------------------------------ [2021-02-18 16:02:33] nikic@php.net Oh, I missed that "new C" and "$c->__construct()" produce different results. Agree that this doesn't seem right. ------------------------------------------------------------------------ [2021-02-18 15:50:42] dirk dot gerigk at atraveo dot com Hi, what i dont get is the different behavior of the twice call $c = new C; $c->__construct(); the first line calles A::__construct and shows 5 the second lines calls then the method with a separate static and shows 1 So this statement is not valid here: "if the method is inherited, then it also gets separate static variables" If this statement is right, then the two calls have to have 1 and 2 as result, no 5 and 1, or? Normaly u dont call $c->__construct() on an existing object, but why is direct call of __construct so different? But thanks, for the reply. ------------------------------------------------------------------------ [2021-02-18 11:01:26] nikic@php.net In PHP, static variables are bound to a specific method -- if the method is inherited, then it also gets separate static variables. This means that C::__construct() has static variables independent of A::__construct(). I'm going to close this as a duplicate of bug #74198, because the behavior of static variables in methods and their interaction with inheritance is currently not documented. ------------------------------------------------------------------------ [2019-01-29 09:11:40] dirk dot gerigk at atraveo dot com Description: ------------ Unexpected behavior in extended class, when using static variable in constructor and call the method directly I was testing the concept of immutable classes and was coming to an point where i called the __construct method directly. I injected an static $var in the method and found that unexpected behavior. I seems that the C class that not defines an constructor once call the constructor with the previews incremented static var, but the direct call of the method gets an fresh static var. I think it is not normal to call the constructor directly as method, but when it is it should have same result as the class B. The call of $c->__construct(); should get 6 not 1. Or there any explanation to this? Test script: --------------- class A { public function __construct(){ static $test = 0; print (++$test); } } class B extends A { public function __construct(){ parent::__construct(); } } class C extends A {} $a = new A; $a->__construct(); $b = new B; $b->__construct(); $c = new C; $c->__construct(); Expected result: ---------------- 123456 Actual result: -------------- 123451 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=77537&edit=1