Wrong withCount with hasManyThrough() relations

[mkuzmych]

• Laravel Version: 5.7.9
• PHP Version: 7.1.6
• Database Driver & Version: mysql 5.6.25

Description:

Wrong withCount with hasManyThrough() relations

Steps To Reproduce:

Relations

I have relations with parent_id on table categories:
categories
id - integer
categories
id - integer
parent_id - integer
products
id - integer
category_id - integer

Model

class Category extends Model {
    public function products()
    {
        return $this->hasMany('App\Product');
    }
    public function sub_products()
    {
        return $this->hasManyThrough('App\Product','App\Category','parent_id','category_id','id','id');
    }
}

Problem

I make request:

Category::where('id','=',9)->with('sub_products')->withCount('sub_products')->get();

Request return sub_products items, but count return always 0! Thanks!

[staudenmeir]

I can reproduce this. It also affects Category::has('sub_products') queries.

[mkuzmych]

Yes, with has I reproduce this too, and have problem.