I had a method:

public function getAllVariants(): HasMany
{
    return $this->hasMany(ProductVariant::class, 'product_id', 'id')->with(['product', 'attribute_values', 'image', 'description']);
}

I tried modifying it:

public function getAllVariants(): HasMany
{
        $allVariants = $this->hasMany(ProductVariant::class, 'product_id', 'id')->with(['product', 'attribute_values', 'image', 'description']);
    
    if ($allVariants->count() === 0) {
        
       $variantByCode = ProductVariant::where('code', $this->code)->first();

        if (!$variantByCode) {
            
            $variants = $this->hasMany(ProductVariant::class, 'product_id', 'id')->where('id', '=', 0); 
        }

        // Retrieve variants related to the product
        $allVariants = ProductVariant::where('product_id', $variantByCode->product_id)
            ->with(['product', 'attribute_values', 'image', 'description']);
    }

    return $allVariants;
}

This modification is needed to connect product variants with each other. To do this, I changed the product_id query. And I started getting an error:

Blockquote Return value must be of type IlluminateDatabaseEloquentRelationsHasMany, IlluminateDatabaseEloquentBuilder returned

I also want to note that in the future this code will be used as:

$variants = $this->getAllVariants
       ->each(fn(ProductVariant $variant) => $variant->setRelation('product', $this))
       ->sortBy('position');

How can I fix the error?