This does not fix the issue where empty/null query parameters are not appended in pagination query strings.

I have submitted a form whose fields can be empty and the resulting query string is pretraga?grad=&broj_soba=&m2_od=&m2_do=&cena_od=&cena_do=.

Filter template (realestate\resources\views\components\listings\list\form.blade.php):

<form class="border border-secondary-subtle rounded-3 p-3 mb-3" action="{{ route('listing_search') }}" method="get" novalidate>
  <h3 class="fw-semibold mb-3">Pretraga</h3>

  <div class="row gy-3 mb-3">
    <div class="col-6 col-md-12">
      <div class="form-floating">
        <input class="form-control" type="text" id="city" name="grad" maxlength="255">
        <label for="city">Grad</label>
      </div>
    </div>

    <div class="col-6 col-md-12">
      <div class="form-floating">
        <input class="form-control" type="number" id="room_count" name="broj_soba" min="0">
        <label for="room_count">Broj soba</label>
      </div>
    </div>

    <div class="col-6 col-md-12">
      <div class="input-group">
        <div class="form-floating">
          <input class="form-control" type="number" id="m2_from" name="m2_od" min="0">
          <label for="m2_from">Površina od</label>
        </div>

        <div class="form-floating">
          <input class="form-control" type="number" id="m2_to" name="m2_do" min="0">
          <label for="m2_to">Površina do</label>
        </div>
      </div>
    </div>

    <div class="col-6 col-md-12">
      <div class="input-group">
        <div class="form-floating">
          <input class="form-control" type="number" id="price_from" name="cena_od" min="0">
          <label for="price_from">Cena od</label>
        </div>

        <div class="form-floating">
          <input class="form-control" type="number" id="price_to" name="cena_do" min="0">
          <label for="price_to">Cena do</label>
        </div>
      </div>
    </div>
  </div>

  <input class="btn btn-primary fw-semibold" type="submit" value="Pretražite">
</form>

search passes filtered listings to the view (realestate\app\Http\Controllers\ListingController.php):

public function search(Request $request)
{
    $order = $request->query("redosled", "");
    $listings = $this->listingServ->filter($request->query(), $order);
    // $listings = $this->appends($listings, $request->query());

    $data = $this->indexData($listings);
    return view("listings.listing_list", $data);
}

filter returns filtered listings page (realestate\app\Services\ListingService.php):

public function filter(array $data, string $order)
{
    // 1 Parametrized queries
    $query = Listing::query();
    $query = ListingFilters::filter($query, $data);
    return $this->orderPaginate($query, $order);
}

Functions that filters the listings (realestate\app\Services\ListingFilters.php):

private static function whereCity(Builder $query, array $data)
{
    $city = $data["grad"];

    // 1 Parametrized queries
    return !empty($city) ? $query->whereLike("city", "%{$city}%") : $query;
}

private static function whereRoomCount(Builder $query, array $data)
{
    $roomCount = $data["broj_soba"];

    // 1 Parametrized queries
    return !empty($roomCount) ? $query->where("room_count", "=", (int) $roomCount) : $query;
}

private static function whereArea(Builder $query, array $data)
{
    $area_from = $data["m2_od"];
    $area_to = $data["m2_do"];

    // 1 Parametrized queries
    if (!empty($area_from)) $query = $query->where("area", ">=", (int) $area_from);
    if (!empty($area_to)) $query = $query->where("area", "<=", (int) $area_to);
    return $query;
}

private static function wherePrice(Builder $query, array $data)
{
    $price_from = $data["cena_od"];
    $price_to = $data["cena_do"];

    // 1 Parametrized queries
    if (!empty($price_from)) $query = $query->where("price", ">=", (int) $price_from);
    if (!empty($price_to)) $query = $query->where("price", "<=", (int) $price_to);
    return $query;
}

public static function filter(Builder $query, array $data)
{
    $query = self::whereCity($query, $data);
    $query = self::whereRoomCount($query, $data);
    $query = self::whereArea($query, $data);
    $query = self::wherePrice($query, $data);
    return $query;
}

Pagination template (realestate\resources\views\components\pagination.blade.php):

@if ($listings->hasPages())
  <ul class="pagination mb-3">
    <li class="page-item {{ $listings->currentPage() === 1 ? 'disabled' : '' }}">
      <a class="page-link" href="{{ $listings->withQueryString()->previousPageUrl() ?? '' }}">Prethodna</a>
    </li>

    @if ($listings->currentPage() > 2)
      <li class="page-item">
        <a class="page-link" href="{{ $listings->withQueryString()->url(1) }}">1</a>
      </li>
    @endif

    @if ($listings->currentPage() > 1)
      <li class="page-item">
        <a class="page-link" href="{{ $listings->withQueryString()->previousPageUrl() }}">{{ $listings->currentPage() - 1 }}</a>
      </li>
    @endif

    <li class="page-item active">
      <a class="page-link" href="{{ $listings->withQueryString()->url($listings->currentPage()) }}">{{ $listings->currentPage() }}</a>
    </li>

    @if ($listings->currentPage() < $listings->lastPage())
      <li class="page-item">
        <a class="page-link" href="{{ $listings->withQueryString()->nextPageUrl() }}">{{ $listings->currentPage() + 1 }}</a>
      </li>
    @endif

    @if ($listings->currentPage() < $listings->lastPage() - 1)
      <li class="page-item">
        <a class="page-link" href="{{ $listings->withQueryString()->url($listings->lastPage()) }}">{{ $listings->lastPage() }}</a>
      </li>
    @endif

    <li class="page-item {{ $listings->currentPage() === $listings->lastPage() ? 'disabled' : '' }}">
      <a class="page-link" href="{{ $listings->withQueryString()->nextPageUrl() ?? '' }}">Sledeća</a>
    </li>
  </ul>
@endif

When I hover over pagination links after searching/filtering, their URLs do not include other query parameters.

What dd($request->query()) prints:

array:6 [▼ // app\Http\Controllers\ListingController.php:113
  "grad" => null
  "broj_soba" => null
  "m2_od" => null
  "m2_do" => null
  "cena_od" => null
  "cena_do" => null
]