Rewrote the check for closed connections. The crucial part is now gua…

…rded but the lock is only acquired when connection list needs to be modified. This avoids unnecessary locking.

clients/rospy/src/rospy/topics.py

@@ -459,19 +459,15 @@ def cleanup_cb_wrapper(s):
             return True
 
     def check(self):
-        new_connections = self.connections[:]
-        removed_connection = False
-
-        for fd in self.connection_poll.error_iter():
-            to_remove = [x for x in new_connections if x.fileno() == fd]
-
-            for x in to_remove:
-                removed_connection = True
-                rospydebug("removing connection to %s, connection error detected"%(x.endpoint_id))
-                self._remove_connection(new_connections, x)
-
-        if removed_connection:
-            self.connections = new_connections
+        fds_to_remove = list(self.connection_poll.error_iter())
+        if fds_to_remove:
+            with self.c_lock:
+                new_connections = self.connections[:]
+                to_remove = [x for x in new_connections if x.fileno() in fds_to_remove]
+                for x in to_remove:
+                    rospydebug("removing connection to %s, connection error detected"%(x.endpoint_id))
+                    self._remove_connection(new_connections, x)
+                self.connections = new_connections
 
     def remove_connection(self, c):
         """