Db::selectOne() should return null if result is empty

includes/model/Shifts_model.php

@@ -182,7 +182,7 @@ function NeededAngeltypes_by_ShiftsFilter(ShiftsFilter $shiftsFilter)
 /**
  * @param array $shift
  * @param array $angeltype
- * @return array
+ * @return array|null
  */
 function NeededAngeltype_by_Shift_and_Angeltype($shift, $angeltype)
 {

includes/pages/user_myshifts.php

@@ -71,7 +71,7 @@ function user_myshifts()
                 $shifts_user['UID'],
             ]
         );
-        if (count($shift) > 0) {
+        if (!empty($shift)) {
             $freeloaded = $shift['freeloaded'];
             $freeload_comment = $shift['freeload_comment'];
 

src/Database/Db.php

@@ -45,14 +45,19 @@ class Db
      *
      * @param string $query
      * @param array  $bindings
-     * @return array
+     * @return array|null
      */
     public static function selectOne($query, array $bindings = [])
     {
         $result = self::connection()->selectOne($query, $bindings);
 
         // @TODO: remove typecast
-        return (array)$result;
+        $result = (array)$result;
+        if (empty($result)) {
+            return null;
+        }
+
+        return $result;
     }
 
     /**