0

I'm using an observer class in my laravel project and it's throwing a mysterious error. The trace is below. It appears after some searching that in the /vendor/laravel/framework/src/Illuminate/Events/Dispatcher.php(237) class, the dispatch method attempts to run the listener on a null payload which I believe is the model instance passed to the listener. The model event I'm using is the "saving" event but the controller action being called is only performing a select query and it's not making any changes so I would not expect this event to be thrown.

I have confirmed that by not registering the observer in a service provider, the error ceases to exist, however when I register the observer and comment out any methods in the observer class, it still occurs.

Is this a laravel bug?

I included:

  • controller action
  • Dispatcher class
  • exception trace

** edit **

  • service provider boot method

Controller Action:

    /**
     * Display a listing of the resource.
     *
     * @param App\Models\Crop $crop
     * @return \Illuminate\Http\Response
     */
    public function index(Request $request)
    {
        $crop = null;
        if ($request->filled('crop_id')) {
            $crop = Crop::find($request->query('crop_id'));
            $chyps = $crop->harvest_year_pubs->withoutGlobalScopes();
        } else {
            $chyps = CropHarvestYearPublication::orderBy('crop_id');
        }

        if ($request->filled('sort_by')) {
            if ($request->query('sort_order') === 'desc') {
                $chyps->sortByDesc($request->query('sort_by'));
            } else {
                $chyps->sortBy($request->query('sort_by'));
            }
        }

        return view('admin.data.chyp.index', [
            'chyps' => $chyps->paginate(15),
            'crop'  => $crop,
            'crops' => Crop::withoutGlobalScopes()->get(),
            'sort_by' => $request->query('sort_by'),
            'sort_order' => $request->query('sort_order')
        ]);
    }

/vendor/laravel/framework/src/Illuminate/Events/Dispatcher.php line 237 is where the error occurs:

   /**
     * Fire an event and call the listeners.
     *
     * @param  string|object  $event
     * @param  mixed  $payload
     * @param  bool  $halt
     * @return array|null
     */
    public function dispatch($event, $payload = [], $halt = false)
    {
        // When the given "event" is actually an object we will assume it is an event
        // object and use the class as the event name and this event itself as the
        // payload to the handler, which makes object based events quite simple.
        [$event, $payload] = $this->parseEventAndPayload(
            $event, $payload
        );

        if ($this->shouldBroadcast($payload)) {
            $this->broadcastEvent($payload[0]);
        }

        $responses = [];

        foreach ($this->getListeners($event) as $listener) {
            $response = $listener($event, $payload); // LINE 237 - where the error is thrown

            // If a response is returned from the listener and event halting is enabled
            // we will just return this response, and not call the rest of the event
            // listeners. Otherwise we will add the response on the response list.
            if ($halt && ! is_null($response)) {
                return $response;
            }

            // If a boolean false is returned from a listener, we will stop propagating
            // the event to any further listeners down in the chain, else we keep on
            // looping through the listeners and firing every one in our sequence.
            if ($response === false) {
                break;
            }

            $responses[] = $response;
        }

        return $halt ? null : $responses;
    }

The Exception Trace:

[2021-02-17 14:33:44] testing.ERROR: Function name must be a string {"userId":1,"exception":"[object] (Error(code: 0): Function name must be a string at /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Events/Dispatcher.php:392)
[stacktrace]
#0 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Events/Dispatcher.php(237): Illuminate\\Events\\Dispatcher->Illuminate\\Events\\{closure}('eloquent.retrie...', Array)
#1 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Concerns/HasEvents.php(189): Illuminate\\Events\\Dispatcher->dispatch('eloquent.retrie...', Array)
#2 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Model.php(434): Illuminate\\Database\\Eloquent\\Model->fireModelEvent('retrieved', false)
#3 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Builder.php(345): Illuminate\\Database\\Eloquent\\Model->newFromBuilder(Object(stdClass))
#4 [internal function]: Illuminate\\Database\\Eloquent\\Builder->Illuminate\\Database\\Eloquent\\{closure}(Object(stdClass))
#5 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Builder.php(344): array_map(Object(Closure), Array)
#6 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Support/Traits/ForwardsCalls.php(23): Illuminate\\Database\\Eloquent\\Builder->hydrate(Array)
#7 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Model.php(1885): Illuminate\\Database\\Eloquent\\Model->forwardCallTo(Object(Illuminate\\Database\\Eloquent\\Builder), 'hydrate', Array)
#8 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Builder.php(588): Illuminate\\Database\\Eloquent\\Model->__call('hydrate', Array)
#9 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Builder.php(572): Illuminate\\Database\\Eloquent\\Builder->getModels(Array)
#10 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Builder.php(772): Illuminate\\Database\\Eloquent\\Builder->get(Array)
#11 /Users/apages/code/variety-testing/app/Http/Controllers/Admin/CropHarvestYearPublicationController.php(38): Illuminate\\Database\\Eloquent\\Builder->paginate(15)
#12 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Routing/Controller.php(54): App\\Http\\Controllers\\Admin\\CropHarvestYearPublicationController->index(Object(Illuminate\\Http\\Request))
#13 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Routing/ControllerDispatcher.php(45): Illuminate\\Routing\\Controller->callAction('index', Array)
#14 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Routing/Route.php(254): Illuminate\\Routing\\ControllerDispatcher->dispatch(Object(Illuminate\\Routing\\Route), Object(App\\Http\\Controllers\\Admin\\CropHarvestYearPublicationController), 'index')
#15 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Routing/Route.php(197): Illuminate\\Routing\\Route->runController()
#16 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Routing/Router.php(693): Illuminate\\Routing\\Route->run()
#17 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(128): Illuminate\\Routing\\Router->Illuminate\\Routing\\{closure}(Object(Illuminate\\Http\\Request))
#18 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Routing/Middleware/SubstituteBindings.php(50): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#19 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): Illuminate\\Routing\\Middleware\\SubstituteBindings->handle(Object(Illuminate\\Http\\Request), Object(Closure))
#20 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/VerifyCsrfToken.php(78): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#21 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): Illuminate\\Foundation\\Http\\Middleware\\VerifyCsrfToken->handle(Object(Illuminate\\Http\\Request), Object(Closure))
#22 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/View/Middleware/ShareErrorsFromSession.php(49): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#23 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): Illuminate\\View\\Middleware\\ShareErrorsFromSession->handle(Object(Illuminate\\Http\\Request), Object(Closure))
#24 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Session/Middleware/StartSession.php(121): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#25 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Session/Middleware/StartSession.php(63): Illuminate\\Session\\Middleware\\StartSession->handleStatefulRequest(Object(Illuminate\\Http\\Request), Object(Illuminate\\Session\\Store), Object(Closure))
#26 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): Illuminate\\Session\\Middleware\\StartSession->handle(Object(Illuminate\\Http\\Request), Object(Closure))
#27 /Users/apages/code/variety-testing/app/Http/Middleware/CASAuth.php(46): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#28 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): App\\Http\\Middleware\\CASAuth->handle(Object(Illuminate\\Http\\Request), Object(Closure), 'admin')
#29 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/AddQueuedCookiesToResponse.php(37): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#30 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): Illuminate\\Cookie\\Middleware\\AddQueuedCookiesToResponse->handle(Object(Illuminate\\Http\\Request), Object(Closure))
#31 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/EncryptCookies.php(67): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#32 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): Illuminate\\Cookie\\Middleware\\EncryptCookies->handle(Object(Illuminate\\Http\\Request), Object(Closure))
#33 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(103): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#34 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Routing/Router.php(695): Illuminate\\Pipeline\\Pipeline->then(Object(Closure))
#35 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Routing/Router.php(670): Illuminate\\Routing\\Router->runRouteWithinStack(Object(Illuminate\\Routing\\Route), Object(Illuminate\\Http\\Request))
#36 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Routing/Router.php(636): Illuminate\\Routing\\Router->runRoute(Object(Illuminate\\Http\\Request), Object(Illuminate\\Routing\\Route))
#37 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Routing/Router.php(625): Illuminate\\Routing\\Router->dispatchToRoute(Object(Illuminate\\Http\\Request))
#38 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(166): Illuminate\\Routing\\Router->dispatch(Object(Illuminate\\Http\\Request))
#39 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(128): Illuminate\\Foundation\\Http\\Kernel->Illuminate\\Foundation\\Http\\{closure}(Object(Illuminate\\Http\\Request))
#40 /Users/apages/code/variety-testing/vendor/barryvdh/laravel-debugbar/src/Middleware/InjectDebugbar.php(60): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#41 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): Barryvdh\\Debugbar\\Middleware\\InjectDebugbar->handle(Object(Illuminate\\Http\\Request), Object(Closure))
#42 /Users/apages/code/variety-testing/vendor/fideloper/proxy/src/TrustProxies.php(57): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#43 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): Fideloper\\Proxy\\TrustProxies->handle(Object(Illuminate\\Http\\Request), Object(Closure))
#44 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/TransformsRequest.php(21): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#45 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): Illuminate\\Foundation\\Http\\Middleware\\TransformsRequest->handle(Object(Illuminate\\Http\\Request), Object(Closure))
#46 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/TransformsRequest.php(21): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#47 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): Illuminate\\Foundation\\Http\\Middleware\\TransformsRequest->handle(Object(Illuminate\\Http\\Request), Object(Closure))
#48 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/ValidatePostSize.php(27): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#49 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): Illuminate\\Foundation\\Http\\Middleware\\ValidatePostSize->handle(Object(Illuminate\\Http\\Request), Object(Closure))
#50 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/PreventRequestsDuringMaintenance.php(86): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#51 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): Illuminate\\Foundation\\Http\\Middleware\\PreventRequestsDuringMaintenance->handle(Object(Illuminate\\Http\\Request), Object(Closure))
#52 /Users/apages/code/variety-testing/vendor/fruitcake/laravel-cors/src/HandleCors.php(37): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#53 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(167): Fruitcake\\Cors\\HandleCors->handle(Object(Illuminate\\Http\\Request), Object(Closure))
#54 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(103): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}(Object(Illuminate\\Http\\Request))
#55 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(141): Illuminate\\Pipeline\\Pipeline->then(Object(Closure))
#56 /Users/apages/code/variety-testing/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(110): Illuminate\\Foundation\\Http\\Kernel->sendRequestThroughRouter(Object(Illuminate\\Http\\Request))
#57 /Users/apages/code/variety-testing/public/index.php(17): Illuminate\\Foundation\\Http\\Kernel->handle(Object(Illuminate\\Http\\Request))
#58 /Users/apages/code/variety-testing/server.php(21): require_once('/Users/apages/c...')
#59 {main}

Service provider boot method

    /**
     * Bootstrap services.
     *
     * @return void
     */
    public function boot()
    {
 
        CropHarvestYearPublication::observe(CropHarvestYearPublication::class);

    }
Improve this question
2
  • Check name spaces , also provide the files up the dependency graph i.e. your registration code in event service provider etc. Also as a side note are you generating using the cli? Commented Feb 18, 2021 at 16:34
  • I verified that the namespaces in the observer, model, service provider and controller classes are correct. I included the line in the service provider in the main section. And yes I generated the observer using the cli, but even when the observer class is empty, I still get the error. Commented Feb 18, 2021 at 17:40

1 Answer 1

Reset to default
0

based on your latest edit I see one problem, you are using same class names for your observer and model I would recommend you to alias either your model or your observer like so

Aliasing model

use App\Models\CropHarvestYearPublication as CropHarvestYearPublicationModel;
use App\Observers\CropHarvestYearPublication;

/**
 * Register any events for your application.
 *
 * @return void
 */
public function boot()
{
    CropHarvestYearPublicationModel::observe(CropHarvestYearPublication::class);
}

Aliasing observer

use App\Models\CropHarvestYearPublication;
use App\Observers\CropHarvestYearPublication as CropHarvestYearPublicationObserver;

/**
 * Register any events for your application.
 *
 * @return void
 */
public function boot()
{
    CropHarvestYearPublication::observe(CropHarvestYearPublicationObserver::class);
}

That's probably the reason for your error. Give it a try

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