Abort in-flight FFI connect on disconnect so a cancelled handshake cannot panic the host

.changeset/abort_in_flight_ffi_connect.md

@@ -0,0 +1,15 @@
+---
+livekit-ffi: patch
+---
+
+# Abort in-flight FFI connect on disconnect
+
+Cancelling `room.connect()` from a language binding left `Room::connect` running,
+and a later ReadyFor timeout sent Panic into the host (python-sdks#785). Connect
+now allocates an abortable handle immediately; DisconnectRequest cancels the
+handshake, joins the connect task, and `close()`s any Room that already
+completed (rust-sdks#1334: dropping a completed Room without close keeps
+`engine_task`/`room_task` alive). Abort before `Room::connect` returns Ok does
+not enter `SessionInner::close`; that leftover stays in `livekit/`. ReadyFor on
+that early handle is accepted during handshake. Missed ReadyFor fails that room
+instead of panicking the process.

livekit-ffi-node-bindings/proto/room_pb.d.ts

@@ -308,6 +308,18 @@ export declare class ConnectResponse extends Message<ConnectResponse> {
    */
   asyncId?: bigint;
 
+  /**
+   * Allocated as soon as ConnectRequest is received, before Room::connect
+   * finishes. DisconnectRequest with this handle aborts the in-flight
+   * handshake and close()s any Room that already completed (rust-sdks#1334:
+   * dropping a completed Room without close leaks ICE sockets). Old clients
+   * ignore this proto2 optional field. A missed ReadyFor handshake must fail
+   * this room only, never Panic the host (python-sdks#785).
+   *
+   * @generated from field: optional uint64 room_handle = 2;
+   */
+  roomHandle?: bigint;
+
   constructor(data?: PartialMessage<ConnectResponse>);
 
   static readonly runtime: typeof proto2;

livekit-ffi-node-bindings/proto/room_pb.js

@@ -164,6 +164,7 @@ const ConnectResponse = /*@__PURE__*/ proto2.makeMessageType(
   "livekit.proto.ConnectResponse",
   () => [
     { no: 1, name: "async_id", kind: "scalar", T: 4 /* ScalarType.UINT64 */, req: true },
+    { no: 2, name: "room_handle", kind: "scalar", T: 4 /* ScalarType.UINT64 */, opt: true },
   ],
 );
 

livekit-ffi/protocol/room.proto

@@ -35,6 +35,13 @@ message ConnectRequest {
 }
 message ConnectResponse {
   required uint64 async_id = 1;
+  // Allocated as soon as ConnectRequest is received, before Room::connect
+  // finishes. DisconnectRequest with this handle aborts the in-flight
+  // handshake and close()s any Room that already completed (rust-sdks#1334:
+  // dropping a completed Room without close leaks ICE sockets). Old clients
+  // ignore this proto2 optional field. A missed ReadyFor handshake must fail
+  // this room only, never Panic the host (python-sdks#785).
+  optional uint64 room_handle = 2;
 }
 message ConnectCallback {
   message ParticipantWithTracks {