Prevent object serialization in session

includes/model/ShiftsFilter.php

@@ -48,7 +48,7 @@ class ShiftsFilter
      * @param int[] $rooms
      * @param int[] $types
      */
-    public function __construct($user_shifts_admin, $rooms, $types)
+    public function __construct($user_shifts_admin = false, $rooms = [], $types = [])
     {
         $this->rooms = $rooms;
         $this->types = $types;
@@ -62,6 +62,34 @@ class ShiftsFilter
         }
     }
 
+    /**
+     * @return array
+     */
+    public function sessionExport()
+    {
+        return [
+            'userShiftsAdmin' => $this->userShiftsAdmin,
+            'filled'          => $this->filled,
+            'rooms'           => $this->rooms,
+            'types'           => $this->types,
+            'startTime'       => $this->startTime,
+            'endTime'         => $this->endTime,
+        ];
+    }
+
+    /**
+     * @param array $data
+     */
+    public function sessionImport($data)
+    {
+        $this->userShiftsAdmin = $data['userShiftsAdmin'];
+        $this->filled = $data['filled'];
+        $this->rooms = $data['rooms'];
+        $this->types = $data['types'];
+        $this->startTime = $data['startTime'];
+        $this->endTime = $data['endTime'];
+    }
+
     /**
      * @return int unix timestamp
      */

includes/pages/user_shifts.php

@@ -177,18 +177,19 @@ function view_user_shifts()
     $rooms = load_rooms();
     $types = load_types();
 
-    if (!$session->has('ShiftsFilter')) {
+    if (!$session->has('shifts-filter')) {
         $room_ids = [
             $rooms[0]['id']
         ];
         $type_ids = array_map('get_ids_from_array', $types);
         $shiftsFilter = new ShiftsFilter(in_array('user_shifts_admin', $privileges), $room_ids, $type_ids);
-        $session->set('ShiftsFilter', $shiftsFilter);
+        $session->set('shifts-filter', $shiftsFilter->sessionExport());
     }
 
-    /** @var ShiftsFilter $shiftsFilter */
-    $shiftsFilter = $session->get('ShiftsFilter');
+    $shiftsFilter = new ShiftsFilter();
+    $shiftsFilter->sessionImport($session->get('shifts-filter'));
     update_ShiftsFilter($shiftsFilter, in_array('user_shifts_admin', $privileges), $days);
+    $session->set('shifts-filter', $shiftsFilter->sessionExport());
 
     $shiftCalendarRenderer = shiftCalendarRendererByShiftFilter($shiftsFilter);