Merge pull request 'fix empty but non-null date entries' (#630) from halfprice-fee into staging

Reviewed-on: #630

src/model/user.rs

@@ -362,10 +362,14 @@ ASKÖ Ruderverein Donau Linz", self.name),
         }
 
         let halfprice = if let Some(member_since_date) = &self.member_since_date {
-            let member_since_date =
-                NaiveDate::parse_from_str(member_since_date, "%Y-%m-%d").unwrap();
-            let halfprice_startdate = NaiveDate::from_ymd_opt(Local::now().year(), 7, 1).unwrap();
-            member_since_date >= halfprice_startdate
+            if let Ok(member_since_date) = NaiveDate::parse_from_str(member_since_date, "%Y-%m-%d")
+            {
+                let halfprice_startdate =
+                    NaiveDate::from_ymd_opt(Local::now().year(), 7, 1).unwrap();
+                member_since_date >= halfprice_startdate
+            } else {
+                false
+            }
         } else {
             false
         };