Using whereHas() with HasManyThrough Relationships

I’ve discovered an issue with Eloquent in which using the whereHas() method with a HasManyThrough relationship returns the wrong results.

For instance, if I have the following model structure:

Business
  - hasMany Lead
  - hasManyThrough Purchase (through Lead)
Lead
  - belongsTo Business
  - hasOne Purchase
Purchase
  - belongsTo Lead

the following code will yield unexpected results:

$businesses = Business::whereHas('purchases', function($query)
{
    $query->where( // insert where clause here );
})->get();

I’ve sent a pull request to fix the issue but it needs to be discussed, so for now you can do use nested whereHas() calls like so:

$businesses = Business::whereHas('leads', function($query)
{
    $query->whereHas('purchase', function($query)
    {
        $query->where( // insert where clause here );
    });
})
->get();