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#[Override] attribute in trait does not check for parent class implementations #12189
Description
Description
When adding the #[Override] attribute to a trait method, then use-ing it in a class, a runtime error is triggered even if a parent class defines a matching method. This does not happen when an interface with matching signature is encountered.
The following excerpt from the rfc made me expect this would work:
Methods from a used trait behave as if the method definition was copied and pasted into the target class. Specifically the #[\Override] attribute on a trait method requires the existence of a matching method in a parent class or implemented interface.
The following code:
<?php
class A {
public function foo(): void {}
}
interface I {
public function foo(): void;
}
trait T {
#[\Override]
public function foo(): void {
echo 'foo';
}
}
// Works fine
class B implements I {
use T;
}
// Works fine ("copied and pasted into the target class")
class C extends A {
#[\Override]
public function foo(): void {
echo 'foo';
}
}
// Does not work
class D extends A {
use T;
}Resulted in this output:
PHP Fatal error: D::foo() has #[\Override] attribute, but no matching parent method exists in mwe.php on line 13
PHP Stack trace:
PHP 1. {main}() mwe.php:0
Fatal error: D::foo() has #[\Override] attribute, but no matching parent method exists in mwe.php on line 13
Call Stack:
0.0002 364504 1. {main}() mwe.php:0
But I expected no output instead.
PHP Version
8.3.0RC1
Operating System
Windows 11 / Ubuntu 23.10 with WSL
Reacted by Michael Voříšek and Thanh Trần
Activity
ndossche commentedon Sep 12, 2023
Seems to be because of the flag removal code:
The second condition doesn't trigger because the method doesn't belong to the class, it belongs to the trait. However, getting rid of the condition is a bad idea because it may load to modification inside shm as the trait is shared.
And duplicating the function seems like a very ugly solution.
TimWolla commentedon Sep 12, 2023
Without looking yet into this again (I fear it's above my pay-grade based on your description), I wonder why it works fine for interfaces then 🤔
Looking at the tests, it appears this issue found the only case that is not covered by the tests 😔
Fix #[Override] on traits overriding a parent method without a matchi…
Merge branch 'PHP-8.3' into phpgh-12189
Fix #[Override] on traits overriding a parent method without a matchi…
jnoordsij commentedon Sep 15, 2023
@TimWolla thanks for fixing!
TimWolla commentedon Sep 15, 2023
@jnoordsij Thank you for testing the release candidates and also for finding the bug 😃