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Static properties in traits don't override static properties from parent class #10935
Description
Description
The following code:
<?php
class A
{
protected static $instance = null;
public static function getInstance(...$args)
{
if(!isset(self::$instance)){
self::$instance = new static(...$args);
}
return self::$instance;
}
public function getB()
{
return B::class::getInstance();
}
}
class B extends A
{
protected static $instance = null;
public static function getInstance(...$args)
{
if(!isset(self::$instance)){
self::$instance = new static(...$args);
}
return self::$instance;
}
}
var_dump(A::getInstance()->getB()); // BResulted in this output:
<?php
trait Singleton
{
protected static $instance = null;
public static function getInstance(...$args)
{
if(!isset(self::$instance)){
self::$instance = new static(...$args);
}
return self::$instance;
}
}
class A
{
use Singleton;
public function getB()
{
return B::class::getInstance();
}
}
class B extends A
{
use Singleton;
}
var_dump(A::getInstance()->getB()); // A
But I expected this output instead:
var_dump(A::getInstance()->getB()); // B
PHP Version
PHP 8.2.3
Operating System
mac 13.0.1
Activity
iluuu1994 commentedon Mar 25, 2023
Simplified example:
https://3v4l.org/Dll1m
https://3v4l.org/SClLn
The RFC is super old, there's no mention on how this is supposed to behave. The docs aren't telling either. It's reasonable to expect the same behavior as the case without traits.
[-]trait代码复用机制问题[/-][+]Static properties in traits don't override static properties from parent class[/+]Add separate static property through trait if parent already declares it