fix(rtc): avoid mutable default and accept None in LocalParticipant.publish_data

livekit-rtc/livekit/rtc/participant.py

@@ -23,7 +23,18 @@
 import os
 import mimetypes
 import weakref
-from typing import List, Union, Callable, Dict, Awaitable, Optional, Mapping, cast, TypeVar
+from typing import (
+    List,
+    Union,
+    Callable,
+    Dict,
+    Awaitable,
+    Optional,
+    Mapping,
+    cast,
+    TypeVar,
+    Sequence,
+)
 from abc import abstractmethod, ABC
 
 from ._ffi_client import FfiClient, FfiHandle
@@ -317,7 +328,7 @@ async def publish_data(
         payload: Union[bytes, str],
         *,
         reliable: bool = True,
-        destination_identities: List[str] = [],
+        destination_identities: Optional[Sequence[str]] = None,
         topic: str = "",
     ) -> None:
         """
@@ -326,7 +337,7 @@ async def publish_data(
         Args:
             payload (Union[bytes, str]): The data to publish.
             reliable (bool, optional): Whether to send reliably or not. Defaults to True.
-            destination_identities (List[str], optional): List of participant identities to send to. Defaults to [].
+            destination_identities (Optional[Sequence[str]], optional): Sequence of participant identities to send to. Defaults to None.
             topic (str, optional): The topic under which to publish the data. Defaults to "".
 
         Raises:
@@ -344,7 +355,8 @@ async def publish_data(
         req.publish_data.data_len = data_len
         req.publish_data.reliable = reliable
         req.publish_data.topic = topic
-        req.publish_data.destination_identities.extend(destination_identities)
+        if destination_identities:
+            req.publish_data.destination_identities.extend(destination_identities)
 
         queue = FfiClient.instance.queue.subscribe()
         try:

tests/rtc/test_participant_publish_data.py

@@ -0,0 +1,76 @@
+from __future__ import annotations
+
+import inspect
+import os
+import pytest
+
+from livekit import rtc
+from livekit.rtc import _ffi_client
+from livekit.rtc.participant import LocalParticipant
+from livekit.rtc._proto import ffi_pb2 as proto_ffi
+from livekit.rtc._proto import handle_pb2 as proto_handle
+from livekit.rtc._proto import participant_pb2 as proto_participant
+
+
+def _create_local_participant() -> LocalParticipant:
+    room = rtc.Room()
+    return LocalParticipant(
+        room._room_queue,
+        proto_participant.OwnedParticipant(
+            handle=proto_handle.FfiOwnedHandle(id=0),
+            info=proto_participant.ParticipantInfo(
+                sid="PA_TEST",
+                identity="tester",
+            ),
+        ),
+    )
+
+
+def test_publish_data_parameter_default_is_none() -> None:
+    sig = inspect.signature(LocalParticipant.publish_data)
+    param = sig.parameters["destination_identities"]
+    assert param.default is None
+
+
+@pytest.mark.asyncio
+async def test_publish_data_accepts_none_and_sequences(monkeypatch: pytest.MonkeyPatch) -> None:
+    lp = _create_local_participant()
+    captured_requests: list[proto_ffi.FfiRequest] = []
+
+    class _MockFfiClient:
+        def __init__(self) -> None:
+            self.queue: _ffi_client.FfiQueue[proto_ffi.FfiEvent] = _ffi_client.FfiQueue()
+            self._pid = os.getpid()
+
+        def request(self, req: proto_ffi.FfiRequest) -> proto_ffi.FfiResponse:
+            captured_requests.append(req)
+            resp = proto_ffi.FfiResponse()
+            resp.publish_data.async_id = 42
+
+            ev = proto_ffi.FfiEvent()
+            ev.publish_data.async_id = 42
+            self.queue.put(ev)
+            return resp
+
+    mock_client = _MockFfiClient()
+    monkeypatch.setattr(_ffi_client.FfiClient, "_instance", mock_client)
+
+    # 1. Default (omitted)
+    await lp.publish_data(b"msg1")
+    assert list(captured_requests[-1].publish_data.destination_identities) == []
+
+    # 2. Explicit None
+    await lp.publish_data(b"msg2", destination_identities=None)
+    assert list(captured_requests[-1].publish_data.destination_identities) == []
+
+    # 3. Explicit empty list
+    await lp.publish_data(b"msg3", destination_identities=[])
+    assert list(captured_requests[-1].publish_data.destination_identities) == []
+
+    # 4. List of identities
+    await lp.publish_data(b"msg4", destination_identities=["user1", "user2"])
+    assert list(captured_requests[-1].publish_data.destination_identities) == ["user1", "user2"]
+
+    # 5. Tuple of identities
+    await lp.publish_data(b"msg5", destination_identities=("user3", "user4"))
+    assert list(captured_requests[-1].publish_data.destination_identities) == ["user3", "user4"]