Convert local scope to global scope or query by parent attribute - sql

Question

I want to retrieve all comments which belong to active posts.
I have a local scope on my Posts model looking like this.
public function scopePublic($query) {
return $query->whereHas('post', function ($q) {
$q->where('is_public', true);
});
}
Which works fine, but breaks with PHP message: PHP Fatal error: Allowed memory size of X bytes exhausted as soon as I want to convert it to a global scope like this:
static::addGlobalScope('is_public', function (Builder $builder) {
return $builder->whereHas('post', function ($q) {
$q->where('is_public', true);
});
});
My end goal is for all comment queries only to show public comments, unless I specifically ask not to.
I've been through quite a few solutions. I've tried joining the post on the comments, and I tried adding a sub-select to no luck.
$builder->addSelect(['is_public' => Post::select('is_private')
->whereColumn('id', 'comment.post_id')->limit(1)
]);
$builder->join('posts','posts.id','=','comments.post_id')
->where('comments.is_private', false);

Answer 1

Make a new class PublicScope
use Illuminate\Database\Eloquent\Scope;
class CommentPublicScope implements Scope
{
/**
* Apply the scope to a given Eloquent query builder.
*
* #param \Illuminate\Database\Eloquent\Builder $builder
* #param \Illuminate\Database\Eloquent\Model $model
* #return void
*/
public function apply(Builder $builder, Model $model)
{
$builder->whereHas('post', function ($q) {
$q->where('is_public', true);
});
}
}
Then you can add the global scope
Class Comment extends Model
{
protected static function boot()
{
parent::boot();
static::addGlobalScope(new CommentPublicScope);
}
}