[C++] SelectKUnstable can crash on empty inputs #51210

      if (num_rows == 0) {                                                                                                                                                                          
        return Status::OK();                                                                                                                                                                     
      }                                                                                                                                                                                               

  Result<std::shared_ptr<Array>> SelectKUnstable(const Datum& datum, ...) {                        
    ARROW_ASSIGN_OR_RAISE(Datum result,                                                            
                          CallFunction("select_k_unstable", {datum}, &options, ctx));               
    return result.make_array();
  }                                                                                                 

  std::shared_ptr<Array> Datum::make_array() const {                                                                                                                                                  
    DCHECK_EQ(Datum::ARRAY, this->kind());
    return MakeArray(std::get<std::shared_ptr<ArrayData>>(this->value));                                            
  }