Protected properties are not scoped according to their prototype

[bwoebi]

Description

The following code (https://3v4l.org/7Xf05#v8.4.10):

<?php

abstract class P {
    abstract protected $foo { get; }
}

class C1 extends P {
    protected $foo = 1;
}

class C2 extends P {
    protected $foo = 2;
    
    static function foo($c) { return $c->foo; }
}

var_dump(C2::foo(new C2));
var_dump(C2::foo(new C1));

Resulted in this output:

int(2)

Fatal error: Uncaught Error: Cannot access protected property C1::$foo in /in/7Xf05:14
Stack trace:
#0 /in/7Xf05(18): C2::foo(Object(C1))
#1 {main}
  thrown in /in/7Xf05 on line 14

But I expected this output instead:

int(2)
int(1)

Doing the same with methods works flawlessly (https://3v4l.org/iQo81#v8.4.10):

<?php

abstract class P {
    abstract protected function foo();
}

class C1 extends P {
    protected function foo() { return 1; }
}

class C2 extends P {
    protected function foo() { return 2; }
    
    static function doFoo($c) { return $c->foo(); }
}

var_dump(C2::doFoo(new C2));
var_dump(C2::doFoo(new C1));

results in the expected

int(2)
int(1)

PHP Version

PHP 8.4.10

Operating System

No response

[bwoebi]

@iluuu1994 This was very surprising - I just checked the RFC and it says that they work the same than abstract methods:

abstract properties may also be declared protected, just as with abstract methods

So I assume this is a bug in the implementation?

[iluuu1994]

It looks like this is not unique to hooks or abstract properties. https://3v4l.org/OJWLS#v8.4.10

[iluuu1994]

Ah I see @bwoebi already got the solution. 🙂 Using prop_info->prototype looks like the right approach to me.

[bwoebi]

@iluuu1994 Yeah, in the past there was not really a big point in repeating the property definition, so this was rather obscure and irrelevant. With property hooks you now can set protected abstract $prop { get; } on the parent class, so the child has to define it and then it breaks.

Added that as a test case to the PR as well.