fix(voice): Avoid possible race condition.

src/tracking/voice/session.py

@@ -73,11 +73,14 @@ class VoiceSession:
         'start_task', 'expiry_task',
         'data', 'state', 'hourly_rate',
         '_tag', '_start_time',
+        'lock',
         '__weakref__'
     )
 
     _sessions_ = defaultdict(lambda: WeakCache(TTLCache(5000, ttl=60*60)))  # Registry mapping
-    _active_sessions_ = defaultdict(dict)  # Maintains strong references to active sessions
+
+    # Maintains strong references to active sessions
+    _active_sessions_: dict[int, dict[int, 'VoiceSession']] = defaultdict(dict) 
 
     def __init__(self, bot: LionBot, guildid: int, userid: int, data=None):
         self.bot = bot
@@ -96,6 +99,10 @@ class VoiceSession:
         self._tag = None
         self._start_time = None
 
+        # Member session lock
+        # Ensures state changes are atomic and serialised
+        self.lock = asyncio.Lock()
+
     def cancel(self):
         if self.start_task is not None:
             self.start_task.cancel()
@@ -166,6 +173,7 @@ class VoiceSession:
         return self
 
     async def set_tag(self, new_tag):
+        async with self.lock:
             if self.activity is SessionState.INACTIVE:
                 raise ValueError("Cannot set tag on an inactive voice session.")
             self._tag = new_tag
@@ -194,7 +202,8 @@ class VoiceSession:
         """
         await asyncio.sleep(delay)
 
-        logger.debug(
+        async with self.lock:
+            logger.info(
                 f"Starting voice session for member <uid:{self.userid}> in guild <gid:{self.guildid}> "
                 f"and channel <cid:{self.state.channelid}>."
             )
@@ -275,6 +284,7 @@ class VoiceSession:
         """
         Close the session, or cancel the pending session. Idempotent.
         """
+        async with self.lock:
             if self.activity is SessionState.ONGOING:
                 # End the ongoing session
                 now = utc_now()
@@ -302,6 +312,8 @@ class VoiceSession:
             self.data = None
             self.state = None
             self.hourly_rate = None
+            self._tag = None
+            self._start_time = None
 
             # Always release strong reference to session (to allow garbage collection)
             self._active_sessions_[self.guildid].pop(self.userid)