Why is this job value empty?

Between the Mastering Laravel community and the Get Unstuck sessions I offer, I've gotten pretty good at helping people debug their code.

Let's walk through an example in today's tip and see what we can learn.

Consider this simple job and calling code:

class SomeSimpleJob implements ShouldQueue
{
    public function handle(SomeModel $model)
    {
        // job logic here
    }
}

// somewhere in a controller action
SomeSimpleJob::dispatch($someModelTheJobNeeds);

The developer was confused why inside his job's handle method, $model was a new, empty instance of SomeModel and not the one he passed in when dispatching.

Do you see the problem? Pause for a second and see if you can spot it. Take a look at Laravel's job documentation if needed. Read the code example in the docs and carefully compare it to this one.

The problem is that data passed into the job during dispatch is received by the job's constructor, not the handle method. We don't have a constructor method, so the model being passed in is just silently discarded.

So why do we have an empty, new model in our handle method? Laravel is injecting dependencies for us. This is useful when you want to inject a service, but when you try to inject a model, it just creates a new instance and passes it in.

This is a simple fix, and it's an easy mistake to make, but I like the exercise of walking through what happened, how it lines up with Laravel's functionality under the hood, and why it all makes sense.

Pausing for a moment and internalizing this will make us a stronger developer over time, even though it can be frustrating in the moment.

Here to help,

Joel

P.S. And the next time you're struggling alone, don't forget that the community and Get Unstuck sessions are here to help you out.