Broadcast disconnects; update fake client

Implement server-side disconnect lifecycle and update client handling. Added disconnect_client and broadcast_disconnect in server.py to remove clients, close sockets, and notify remaining clients with a disconnect packet; broadcast_transform now uses disconnect_client for failed recipients and logs delivery counts. Updated fake_client.py to handle disconnect packets, remove remote players from its in-memory table, and improve logging. Documentation (docs/dev-log.md and server/README.md) updated to record the change and next steps.

docs/dev-log.md

@@ -417,3 +417,36 @@ Player position: X=2048.00, Y=2048.00, Z=0.00, AngleZ=0.00
 
 - Add disconnect packets when a client leaves.
 - Have fake clients remove remote players when disconnect packets are received.
+
+## 2026-05-31
+
+### What Changed
+
+- Added server-side disconnect packet broadcasting.
+- Updated the fake client to handle disconnect packets.
+- Fake client now removes disconnected remote players from its remote player state table.
+- Tested disconnect lifecycle using the Fallout 4 plugin and fake client.
+
+### What Worked
+
+- Server detected the Fallout 4 plugin disconnecting.
+- Server removed the disconnected client.
+- Server broadcast a disconnect packet to remaining clients.
+- Fake client received the disconnect packet.
+- Fake client removed remote player 2 from its state table.
+- Fake client correctly reported that no remote players were currently tracked.
+
+### What Broke
+
+- Nothing recorded.
+
+### Notes
+
+- The fake client reported `WinError 10054` after the server was stopped manually. This is expected during shutdown and is not a protocol issue.
+- The basic networking lifecycle now works: connect, welcome, transform, disconnect, cleanup.
+
+### Next Steps
+
+- Add protocol documentation for welcome, transform, and disconnect packets.
+- Begin planning a Fallout 4 plugin receive loop.
+- Store remote player state inside the plugin, without spawning actors yet.

server/README.md

@@ -51,6 +51,10 @@ Expected result:
 - `fake_client.py` receives and prints the broadcast transform packets.
 - `fake_client.py` stores the latest remote player state for each `playerId`
   in memory and prints a readable state summary after each transform update.
+- When a client disconnects, the server removes that client and broadcasts a
+  `disconnect` packet with the departed `playerId` to the remaining clients.
+- `fake_client.py` removes disconnected players from its in-memory
+  `remote_players` table and prints the remaining tracked players.
 
 The fake client exists so broadcast behavior can be tested before coordinating a
 second Fallout 4/F4SE instance. It stores remote player transform state only; it

server/fake_client.py

@@ -86,7 +86,7 @@ def print_remote_player(player: dict[str, Any]) -> None:
 
 def print_remote_players() -> None:
     if not remote_players:
-        log("Known remote players: none")
+        log("No remote players currently tracked.")
         return
 
     log("Known remote players:")
@@ -115,10 +115,10 @@ def handle_disconnect_packet(packet: dict[str, Any]) -> None:
 
     removed_player = remote_players.pop(player_id, None)
     if removed_player is None:
-        log(f"Disconnect packet for unknown remote player {player_id}")
+        log(f"Received disconnect for unknown remote player {player_id}.")
         return
 
-    log(f"Removed remote player {player_id}")
+    log(f"Removed remote player {player_id} after disconnect.")
     print_remote_players()
 
 
@@ -132,7 +132,6 @@ def handle_packet(packet: dict[str, Any]) -> None:
     elif packet_type == "disconnect":
         handle_disconnect_packet(packet)
     else:
-        # TODO: Remove remote players when the server broadcasts disconnect packets.
         log(f"Received packet: {packet}")
 
 

server/server.py

@@ -45,9 +45,9 @@ def assign_client(connection: socket.socket, address: tuple[str, int]) -> Client
     return client
 
 
-def remove_client(client: Client) -> None:
+def remove_client(client: Client) -> bool:
     with clients_lock:
-        clients.pop(client.connection, None)
+        return clients.pop(client.connection, None) is not None
 
 
 def send_packet(connection: socket.socket, packet: dict[str, Any]) -> None:
@@ -55,6 +55,19 @@ def send_packet(connection: socket.socket, packet: dict[str, Any]) -> None:
     connection.sendall(encoded)
 
 
+def disconnect_client(client: Client) -> None:
+    if not remove_client(client):
+        return
+
+    try:
+        client.connection.close()
+    except OSError:
+        pass
+
+    log(f"Client disconnected: {client.label} (player {client.player_id})")
+    broadcast_disconnect(client)
+
+
 def handle_client(connection: socket.socket, address: tuple[str, int]) -> None:
     client = assign_client(connection, address)
     log(f"Client connected: {client.label} (player {client.player_id})")
@@ -86,8 +99,7 @@ def handle_client(connection: socket.socket, address: tuple[str, int]) -> None:
         except OSError as error:
             log(f"Client connection error: {client.label} (player {client.player_id}): {error}")
         finally:
-            remove_client(client)
-            log(f"Client disconnected: {client.label} (player {client.player_id})")
+            disconnect_client(client)
 
 
 def handle_line(client: Client, line: str) -> None:
@@ -128,15 +140,37 @@ def broadcast_transform(sender: Client, packet: dict[str, Any]) -> None:
             failed_recipients.append(recipient)
 
     for recipient in failed_recipients:
-        remove_client(recipient)
-        try:
-            recipient.connection.close()
-        except OSError:
-            pass
+        disconnect_client(recipient)
 
     log(f"Broadcast transform from player {sender.player_id} to {len(recipients) - len(failed_recipients)} other client(s)")
 
 
+def broadcast_disconnect(disconnected_client: Client) -> None:
+    packet = {
+        "type": "disconnect",
+        "playerId": disconnected_client.player_id,
+        "serverTime": time.time(),
+    }
+
+    with clients_lock:
+        recipients = list(clients.values())
+
+    failed_recipients: list[Client] = []
+    for recipient in recipients:
+        try:
+            send_packet(recipient.connection, packet)
+        except OSError:
+            failed_recipients.append(recipient)
+
+    for recipient in failed_recipients:
+        disconnect_client(recipient)
+
+    log(
+        f"Broadcast disconnect for player {disconnected_client.player_id} "
+        f"to {len(recipients) - len(failed_recipients)} other client(s)"
+    )
+
+
 def print_packet(client: Client, packet: dict[str, Any]) -> None:
     if packet.get("type") != "transform":
         log(f"Packet from {client.label}: {packet}")