Laravel 5 - Updating associated models using push() - php

Question

I am trying to do this:
$volunteer = Volunteer::with('user')->find($id);
$input = $updateVolunteerRequest->all();
$volunteer->fill($this->fillFields($input));
$volunteer->user->fill([
'email' => $input['email']
]);
$volunteer->push();
But push() method does not seem to work.
It throws the following error:
FatalErrorException in Model.php line 1463:
Call to a member function push() on a non-object
It worked in Laravel 4. Is there a new way of doing this in version 5? Or am I doing something wrong.
I checked $volunteer and it returns the model.

Answer 1

The push method loops through all of the loaded relationships on the model and calls push on them, as well. So, it isn't the push on the $volunteer that's failing, it is a push on a related model that is failing.
In Laravel 4, push has the following code:
foreach ($this->relations as $models)
{
foreach (Collection::make($models) as $model)
{
if ( ! $model->push()) return false;
}
}
In this code, if the relationship returned a NULL, there would be no error. Collection::make(NULL) returns an empty array, so the foreach would never execute. However, in Laravel 5, push has this code:
foreach ($this->relations as $models)
{
$models = is_array($models) ? $models : array($models);
foreach ($models as $model)
{
if ( ! $model->push()) return false;
}
}
In this case, if the relationship is null, there will be an error, since array(NULL) returns an array with one entry: the NULL value. So, the foreach loop will execute, and it will try to call push on the NULL value, resulting in your Call to a member function push() on a non-object error.
So, it looks like this is a bug in Laravel 5.
Edit
It looks like the push() method was updated because of an update made to the Collection object. I have submitted a pull request to correct the issue. You can check out the pull request here, which also contains links to reported issues and other background information.
Edit 2
My pull request was merged in, so you should be able to update your Laravel 5 to the newest version and the issue should be corrected.