Drop the now-unused shell_socket argument to ShellChannelThread

The thread only held the socket to hand on to SubshellManager, which no
longer takes it: the reply goes out through the shell ZMQStream. Nothing
read the attribute, so both the parameter and the field go.

Author: BoykoNeov

ipykernel/kernelapp.py

@@ -412,11 +412,7 @@ def init_control(self, context):
             self.control_socket.router_handover = 1
 
         self.control_thread = ControlThread(daemon=True)
-        self.shell_channel_thread = ShellChannelThread(
-            context,
-            self.shell_socket,
-            daemon=True,
-        )
+        self.shell_channel_thread = ShellChannelThread(context, daemon=True)
 
     def init_iopub(self, context):
         """Initialize the iopub channel."""

ipykernel/shellchannel.py

@@ -22,16 +22,12 @@ class ShellChannelThread(BaseThread):
     def __init__(
         self,
         context: zmq.Context[Any],
-        shell_socket: zmq.Socket[Any],
         **kwargs,
     ):
         """Initialize the thread."""
         super().__init__(name=SHELL_CHANNEL_THREAD_NAME, **kwargs)
         self._manager: SubshellManager | None = None
         self._zmq_context = context  # Avoid use of self._context
-        # No longer passed on to SubshellManager, which now sends on the shell channel
-        # through the stream and never touches the socket. Nothing else reads this.
-        self._shell_socket = shell_socket
         # Set by kernelapp.init_kernel after it builds the shell ZMQStream, since this
         # thread is created before the stream exists.
         self.shell_stream: ZMQStream | None = None