Fix crash

tournaments/models/tournament.py

@@ -690,17 +690,20 @@ class Tournament(models.Model):
 
         # all started matches have ended, possibly
         last_finished_match = self.last_finished_match()
-        # print(f'last_finished_match = {last_finished_match.name}')
-        round_root_index = last_finished_match.round.root_round().index
-        # print(f'round_index = {round_root_index}')
-        if round_root_index == 0:
-            return last_finished_match.round
-        else:
-            round = self.round_set.filter(parent=None,index=round_root_index-1).first()
-            if round:
-                return round
+        if last_finished_match:
+            # print(f'last_finished_match = {last_finished_match.name}')
+            round_root_index = last_finished_match.round.root_round().index
+            # print(f'round_index = {round_root_index}')
+            if round_root_index == 0:
+                return last_finished_match.round
             else:
-                return None
+                round = self.round_set.filter(parent=None,index=round_root_index-1).first()
+                if round:
+                    return round
+                else:
+                    return None
+        else:
+            return None
 
     def last_started_match(self):
         matches = [m for m in self.all_matches(False) if m.start_date]