handle invalid slot states

app/objects/match.py

@@ -257,11 +257,10 @@ def __init__(
 
         self.tourney_clients: set[int] = set()  # player ids
 
+    # TODO: handle user not found in session situation.
     @property  # TODO: test cache speed
     def host(self) -> Player:
-        player = app.state.sessions.players.get(id=self.host_id)
-        assert player is not None
-        return player
+        return app.state.sessions.players.get(id=self.host_id) or app.state.sessions.bot
 
     @property
     def url(self) -> str:

app/objects/player.py

@@ -685,10 +685,12 @@ def leave_match(self) -> None:
                 # player was host, trasnfer to first occupied slot
                 for s in self.match.slots:
                     # add double check to ensure match player
-                    if s.player is not None and s.player.match is not None:
-                        self.match.host_id = s.player.id
-                        self.match.host.enqueue(app.packets.match_transfer_host())
-                        break
+                    if s.player is None or s.player.match is None:
+                        continue
+
+                    self.match.host_id = s.player.id
+                    self.match.host.enqueue(app.packets.match_transfer_host())
+                    break
 
             if self in self.match._refs:
                 self.match._refs.remove(self)