fix(session): prevent race condition during connection cleanup

alissonlauffer · alissonlauffer · commit edb10c602769 · 2026-03-22T14:31:56.000-03:00
Reorder the stop() method to cancel recv_task BEFORE closing the
connection. Previously, closing the connection first would set asyncio
transport callbacks to None while recv_worker() might still be reading,
causing 'TypeError: NoneType object is not callable' in
_SelectorSocketTransport._read_ready().
diff --git a/hydrogram/session/session.py b/hydrogram/session/session.py
@@ -183,9 +183,9 @@ async def stop(self):
 
         self.ping_task_event.clear()
 
-        if self.connection:
-            await self.connection.close()
-
+        # Cancel recv_task first to avoid race condition with connection close
+        # If connection closes before recv_task finishes, asyncio transport callbacks
+        # can become None while still being invoked, causing TypeError
         if self.recv_task and not self.recv_task.done():
             self.recv_task.cancel()
 
@@ -194,6 +194,9 @@ async def stop(self):
 
             self.recv_task = None
 
+        if self.connection:
+            await self.connection.close()
+
         if not self.is_media and callable(self.client.disconnect_handler):
             try:
                 await self.client.disconnect_handler(self.client)
