Handle paginated SMART/SMARTCAM child responses that omit list fields to avoid StopIteration and KeyError crashes on Tapo H500, and add regression coverage for the no-list pagination shape.

Summary

• Fix SmartProtocol._handle_response_lists to safely handle paginated responses that include start_index and sum but do not include any list-typed fields.
• Prevent StopIteration (from next(iter(...))) which surfaces as RuntimeError: coroutine raised StopIteration in async flows.
• Add regression test test_handle_response_lists_no_list_fields in tests/protocols/test_smartprotocol.py.

Why

Some devices (observed with Tapo H500) can return a paginated response shape where no list key is present. Current code assumes at least one list field exists and raises at runtime. This causes repeated update failures during negotiation/discovery.

Changes

• In kasa/protocols/smartprotocol.py:
  • Replace implicit next(iter([...])) assumption with:
    • collect list_keys
    • if empty: log a warning and return without attempting additional pages
    • otherwise proceed with the first list key
• In tests/protocols/test_smartprotocol.py:
  • Add a regression test covering start_index/sum + non-list payload shape.

Test Plan

• Run targeted regression test:
  • python -m pytest -o addopts='' tests/protocols/test_smartprotocol.py::test_handle_response_lists_no_list_fields -q --tb=short
• Verify existing list pagination behavior remains unchanged via existing tests around list handling.
• Local functional validation against environment reproducing H500 negotiation path (no StopIteration / runtime crash in this path).

Notes

• First change resulted in a traceback still showing up:
  2026-05-06 07:21:49.180 Thread-10 (run_forever) udi_interface ERROR Controller:update_dev: Failed to update 'child_component_list': <DeviceType.Hub at 192.168.1.150 - Tapo_H500_06D8 (H50
  0)>
  Traceback (most recent call last):
  File "/usr/home/admin/dev/pg3/plugins/udi-poly-kasa/nodes/Controller.py", line 207, in update_dev
  await dev.update()
  File "/usr/home/admin/dev/pg3/plugins/udi-poly-kasa/kasa/smart/smartdevice.py", line 279, in update
  children_changed = await self._update_children_info()
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/home/admin/dev/pg3/plugins/udi-poly-kasa/kasa/smartcam/smartcamdevice.py", line 114, in _update_children_info
  changed = await self._create_delete_children(
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/home/admin/dev/pg3/plugins/udi-poly-kasa/kasa/smart/smartdevice.py", line 114, in _create_delete_children
  for child in child_device_components_resp["child_component_list"]
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^
  KeyError: 'child_component_list'

• After plugin restart, logs confirmed:

  • RuntimeError: coroutine raised StopIteration no longer appears.
  • New warning path is active repeatedly:
    • smartprotocol:_handle_response_lists ... no list fields in result ... skipping additional list pages
  • Remaining H500 failure is KeyError: 'child_component_list' in
    kasa/smart/smartdevice.py::_create_delete_children.

• Follow-up fix applied in kasa/smart/smartdevice.py:

  • Guard child_device_components_resp.get("child_component_list") and
    child_device_resp.get("child_device_list").
  • If either is missing or not a list, log a warning and treat as empty list.
  • Build smart_children_components only from dict entries containing device_id.
  • This prevents crashes when H500 child component payload is incomplete while
    preserving behavior for normal payloads.

• This change is intentionally narrow and defensive: it only alters behavior when no list-typed fields exist in a response that otherwise looks paginated.

• Existing behavior for normal paginated list responses is unchanged.