Cannot use typed properties in queued listeners

[golonix]

• Telescope Version: v2.1
• Laravel Version: 6.6.0
• PHP Version: 7.4.0
• Database Driver & Version: irrelevant

Description:

When using a queued listener, it is impossible to have typed properties declared in that listener's class.

class SomeListener implements ShouldQueue
{
    use InteractsWithQueue;

    /**
     * @var SubscriptionService
     */
    private SubscriptionService $subscriptionService;

    /**
     * @param SubscriptionService $subscriptionService
     */
    public function __construct(SubscriptionService $subscriptionService)
    {
        $this->subscriptionService = $subscriptionService;
    }

    public function handle(...)
    {
    }
}

When Telescope is enabled code above will produce an error:

Typed property App\Listeners\SomeListener::$subscriptionService must not be accessed before initialization

Steps To Reproduce:

Create any queued listener and enable Telescope.

Issue is caused by ExtractTags::modelsFor() method:

    protected static function modelsFor(array $targets)
    {
        $models = [];

        foreach ($targets as $target) {
            $models[] = collect((new ReflectionClass($target))->getProperties())->map(function ($property) use ($target) {
                $property->setAccessible(true);

                $value = $property->getValue($target); // <-- This throws error

                if ($value instanceof Model) {
                    return [$value];
                } elseif ($value instanceof EloquentCollection) {
                    return $value->flatten();
                }
            })->collapse()->filter()->all();
        }

        return collect(Arr::collapse($models))->unique();
    }

There are possible workarounds:

• do not use typed properties
• always initiate typed property (defacto allow nullable values and set null as default).

IMHO developer should not be forced to either not use typed properties or allow null values in properties.

I've got very simple fix for that, but not sure if that is sufficient (probably not). Simply, there should be check if a property has been initialized before it can be accessed (https://wiki.php.net/rfc/typed_properties_v2#reflection):

    protected static function modelsFor(array $targets)
    {
        $models = [];

        foreach ($targets as $target) {
            $models[] = collect((new ReflectionClass($target))->getProperties())->map(function ($property) use ($target) {
                $property->setAccessible(true);

                // Check if property is initialized (for PHP >= 7.4.0)
                if (PHP_VERSION_ID >= 70400 && is_object($target) && !$property->isInitialized($target)) {
                    return ;
                }

                $value = $property->getValue($target);

                if ($value instanceof Model) {
                    return [$value];
                } elseif ($value instanceof EloquentCollection) {
                    return $value->flatten();
                }
            })->collapse()->filter()->all();
        }

        return collect(Arr::collapse($models))->unique();
    }

If proposed solution is acceptable, I can create MR for that.

[driesvints]

We already solved typed properties in laravel/framework with this PR: laravel/framework#30605

Maybe some ideas from it can be reused here.

[vigneshgurusamy]

@driesvints Any update on this issue?

[driesvints]

Ping @themsaid

[mengidd]

Any update on this? 🙂

[lucasmichot]

I've made a PR for that - see #879

[driesvints]

This was fixed and will be in the next release. Thanks @lucasmichot.