#5172 (render server-initiated turns in a hidden tab, shipped v0.51.743 via
#5218) has a non-blocking multi-pane edge flagged in review: when a
server-initiated turn arrives for a session that is NOT the active pane, the
hidden-tab status poll called _attachServerInitiatedStream() and could not tell
whether the attach actually happened. _attachServerInitiatedStream returned
undefined in all paths, so the poll had no signal — a stop-on-call would cancel
polling while the turn was never rendered, leaving it invisible until the next
user interaction.
Fix: _attachServerInitiatedStream now returns a bool — true when this tab is
responsible for rendering the stream (attached, or already attached to the same
sid/streamId), false when the attach was not consummated (sid not the current
pane, invalid input, or a thrown error). _startHiddenActiveStreamPoll captures
the bool and only calls _stopHiddenActiveStreamPoll() when true; on false it
keeps polling and re-tries on a later tick (e.g. once the user switches the pane
back to sid, or the turn finishes and status returns active_stream_id=null).
Tests in tests/test_hidden_tab_server_initiated_turn.py: assert all return paths
are explicit bool (no bare return), the non-current-pane path returns false, and
the poll gates _stopHiddenActiveStreamPoll on the attach result.
eabbe9a821
