daemon: removed unused variable in sdt code and update to avoid deadlock when deleting nodes due to sdt trying to leverage the same lock on reconnect

daemon/core/emulator/session.py

@@ -1129,13 +1129,16 @@ class Session:
         """
         Clear the nodes dictionary, and call shutdown for each node.
         """
+        nodes_ids = []
         with self.nodes_lock:
             funcs = []
             while self.nodes:
                 _, node = self.nodes.popitem()
-                self.sdt.delete_node(node.id)
+                nodes_ids.append(node.id)
                 funcs.append((node.shutdown, [], {}))
             utils.threadpool(funcs)
+        for node_id in nodes_ids:
+            self.sdt.delete_node(node_id)
 
     def write_nodes(self) -> None:
         """

daemon/core/plugins/sdt.py

@@ -4,7 +4,6 @@ sdt.py: Scripted Display Tool (SDT3D) helper
 
 import logging
 import socket
-import threading
 from typing import IO, TYPE_CHECKING, Dict, Optional, Set, Tuple
 from urllib.parse import urlparse
 
@@ -65,7 +64,6 @@ class Sdt:
         :param session: session this manager is tied to
         """
         self.session: "Session" = session
-        self.lock: threading.Lock = threading.Lock()
         self.sock: Optional[IO] = None
         self.connected: bool = False
         self.url: str = self.DEFAULT_SDT_URL