fix(api): keep ListUpdate.clear in the SIP *_fields helpers

livekit-api/livekit/api/sip_service.py

@@ -57,6 +57,17 @@ def _as_sip_error(err: ServerError) -> ServerError:
     return err
 
 
+def _set_list_update(dst: ListUpdate, value: ListUpdate | list[str]) -> None:
+    """Copy a list argument of the *_fields helpers into the request's ListUpdate."""
+    # The server rejects an empty ListUpdate, failing the whole update, so an empty
+    # value ([] or ListUpdate()) leaves the field unset: the list is not changed.
+    if isinstance(value, ListUpdate):
+        if value.ByteSize():
+            dst.CopyFrom(value)  # keeps clear as well as set/add/remove
+    elif value:
+        dst.set.extend(value)
+
+
 class SipService(Service):
     """Client for LiveKit SIP Service API
 
@@ -193,26 +204,11 @@ async def update_inbound_trunk_fields(
             media=media,
         )
         if numbers is not None:
-            if isinstance(numbers, ListUpdate):
-                update.numbers.set.extend(numbers.set)
-                update.numbers.add.extend(numbers.add)
-                update.numbers.remove.extend(numbers.remove)
-            else:
-                update.numbers.set.extend(numbers)
+            _set_list_update(update.numbers, numbers)
         if allowed_addresses is not None:
-            if isinstance(allowed_addresses, ListUpdate):
-                update.allowed_addresses.set.extend(allowed_addresses.set)
-                update.allowed_addresses.add.extend(allowed_addresses.add)
-                update.allowed_addresses.remove.extend(allowed_addresses.remove)
-            else:
-                update.allowed_addresses.set.extend(allowed_addresses)
+            _set_list_update(update.allowed_addresses, allowed_addresses)
         if allowed_numbers is not None:
-            if isinstance(allowed_numbers, ListUpdate):
-                update.allowed_numbers.set.extend(allowed_numbers.set)
-                update.allowed_numbers.add.extend(allowed_numbers.add)
-                update.allowed_numbers.remove.extend(allowed_numbers.remove)
-            else:
-                update.allowed_numbers.set.extend(allowed_numbers)
+            _set_list_update(update.allowed_numbers, allowed_numbers)
 
         return await self._client.request(
             SVC,
@@ -376,12 +372,7 @@ async def update_outbound_trunk_fields(
             media=media,
         )
         if numbers is not None:
-            if isinstance(numbers, ListUpdate):
-                update.numbers.set.extend(numbers.set)
-                update.numbers.add.extend(numbers.add)
-                update.numbers.remove.extend(numbers.remove)
-            else:
-                update.numbers.set.extend(numbers)
+            _set_list_update(update.numbers, numbers)
 
         return await self._client.request(
             SVC,
@@ -652,12 +643,7 @@ async def update_dispatch_rule_fields(
             attributes=attributes,
         )
         if trunk_ids is not None:
-            if isinstance(trunk_ids, ListUpdate):
-                update.trunk_ids.set.extend(trunk_ids.set)
-                update.trunk_ids.add.extend(trunk_ids.add)
-                update.trunk_ids.remove.extend(trunk_ids.remove)
-            else:
-                update.trunk_ids.set.extend(trunk_ids)
+            _set_list_update(update.trunk_ids, trunk_ids)
 
         return await self._client.request(
             SVC,

tests/api/test_sip_list_update.py

@@ -0,0 +1,70 @@
+# Copyright 2026 LiveKit, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import asyncio
+from typing import Any, List, Optional, Union
+
+import pytest
+
+from livekit.api.sip_service import SipService
+from livekit.protocol.models import ListUpdate
+
+# (method, list argument, field of request.update)
+LIST_FIELDS = [
+    ("update_inbound_trunk_fields", "numbers", "numbers"),
+    ("update_inbound_trunk_fields", "allowed_addresses", "allowed_addresses"),
+    ("update_inbound_trunk_fields", "allowed_numbers", "allowed_numbers"),
+    ("update_outbound_trunk_fields", "numbers", "numbers"),
+    ("update_dispatch_rule_fields", "trunk_ids", "trunk_ids"),
+]
+
+
+def _sent_update(method: str, arg: str, value: Optional[Union[ListUpdate, List[str]]]) -> Any:
+    sent: List[Any] = []
+
+    async def request(
+        service: str, rpc: str, data: Any, headers: Any, response_class: Any, **kwargs: Any
+    ) -> Any:
+        sent.append(data)
+        return response_class()
+
+    svc = SipService(None, "https://example.livekit.cloud", "key", "secret")  # type: ignore[arg-type]
+    svc._client.request = request  # type: ignore[method-assign, assignment]
+    asyncio.run(getattr(svc, method)("ID_1", **{arg: value}))
+    return sent[0].update
+
+
+@pytest.mark.parametrize(("method", "arg", "field"), LIST_FIELDS)
+def test_list_update_clear_is_sent(method: str, arg: str, field: str) -> None:
+    update = _sent_update(method, arg, ListUpdate(clear=True))
+    assert getattr(update, field) == ListUpdate(clear=True)
+
+
+@pytest.mark.parametrize(("method", "arg", "field"), LIST_FIELDS)
+def test_list_and_list_update_values_are_still_sent(method: str, arg: str, field: str) -> None:
+    assert getattr(_sent_update(method, arg, ["a", "b"]), field) == ListUpdate(set=["a", "b"])
+    change = ListUpdate(add=["a"], remove=["b"])
+    assert getattr(_sent_update(method, arg, change), field) == change
+
+
+@pytest.mark.parametrize(("method", "arg", "field"), LIST_FIELDS)
+@pytest.mark.parametrize(
+    "value", [None, [], ListUpdate()], ids=["omitted", "empty-list", "empty-update"]
+)
+def test_omitted_or_empty_list_is_not_sent(
+    method: str, arg: str, field: str, value: Optional[Union[ListUpdate, List[str]]]
+) -> None:
+    # the server rejects an empty ListUpdate ("unsupported list update operation"),
+    # which would fail the whole update, including its other fields
+    assert not _sent_update(method, arg, value).HasField(field)