[5.2] Correctly load nested relationships for polymorphic relations

[phroggyy]

Firstly, this fixes a bug that was created by #13724 whereby eager loads through protected $with would be ignored for polymorphic relations.

When writing tests for the fix, it was discovered that nested relationships are in fact never loaded for polymorphic relations. So that works too now.

This means you can now have something like

class Like extends Model
{
    protected $with = [‘likeable.owner’];

    public function likeable()
    {
        return $this->morphTo();
    }
}

class Post extends Model
{
    public function owner()
    {
        return $this->belongsTo(User::class);
    }
}

[markvaneijk]

Great work, thanks!

[joshbodine21]

Was this not merged into 5.3?

[GrahamCampbell]

It was?

[joshbodine21]

I will need to dig deeper then. It was working great in 5.2.34 and I just upgrade to 5.3 and it no longer seems to work.

[joshbodine21]

I still can't get this to work after upgrading to 5.3. After downgrading, the same code works fine again. Looks like 5.3 still has an issue.

[almas1992]

How can I use whereHas() method ?
like this.....

Like::whereHas('likeable', function ($query) {
			$query->where('id', 0);
		})->get();

[sebastiaanluca]

If the likeable morph model could consist of a post, comment, and a third user model, and only post has the owner relation, what should be the result when trying to load owner on all likeables?

Currently this would throw an exception:

Call to undefined relationship [owner] on model (comment and user)

My goal would be to have something like this in the parent model:

 protected $with = [
    'likeable.owner',
    'likeable.other',
];

Where it would load the owner relation for the post and other for whichever likeable model implements it, ignoring relations that don't exist on morphed models.

[saqueib]

@joshbodine21 did you manage to get it working, I am using Laravel 5.4.36 and not able to load nested relation. I have tried

protected $with = [
    'subject.attachments'
];

and tried directly calling it from query builder

Activity::with('subject.attachments', 'causer')->latest()->get()

Here is an issue which I opened spatie/laravel-activitylog#281
@GrahamCampbell @freekmurze @phroggyy please help on this.

[skcin7]

I'm currently facing the same issue that @saqueib is having. I'm on Laravel 5.5.26.