[Bug]: #On(Phase::handle) turns Event::commit return value into collection

[tsterker]

What happened?

When registering an external event listener with #On(Phase::Handle) the respective Event's commit calls now return the original return value wrapped in a Collection.

How to reproduce the bug

See the example test below, which showcases how we don't get the expected Event::commit return value once we registered our listener. Also note the stray null element, which might somehow be the root cause of implicit wrapping into a collection?

<?php

namespace Tests\Feature;

use Illuminate\Foundation\Testing\RefreshDatabase;
use PHPUnit\Framework\Attributes\Test;
use Tests\TestCase;
use Thunk\Verbs\Attributes\Hooks\On;
use Thunk\Verbs\Event;
use Thunk\Verbs\Facades\Verbs;
use Thunk\Verbs\Lifecycle\Phase;

class ExampleVerbsListenerTest extends TestCase
{
    use RefreshDatabase;

    #[Test]
    public function handle_hook_turns_commit_response_into_collection(): void
    {
        // Get the commit return value before the event listener was registered
        $result = MyEvent::commit();
        $this->assertSame(MyEvent::COMMIT_RETURN_VALUE, $result);

        // Register the event listener
        Verbs::listen(ExampleVerbsListener::class);

        // 💥 See our assetion fail
        $result = MyEvent::commit();
        $this->assertSame(MyEvent::COMMIT_RETURN_VALUE, $result);
    }
}

class MyEvent extends Event
{
    public const COMMIT_RETURN_VALUE = 'Hello!';

    public function handle(): string
    {
        return self::COMMIT_RETURN_VALUE;
    }
}

class ExampleVerbsListener
{
    #[On(Phase::Handle)]
    public function handle(Event $event): void {}
}

Package Version

0.7.0

PHP Version

8.2.25

Laravel Version

10.48.29

Which operating systems does with happen with?

macOS

Notes

No response

[tsterker]

ℹ️ Update:

I created a PR with a failing test (so far) to illustrate the actual issue, which seems to only occur when using the generic Event base class as the type hint for the listener handle method: #218

Update(2025-05-27): The root cause has been identified and a proposed fix was pushed to the PR.

FYI @DanielCoulbourne