start_drain_thread and start_session_channel_reaper checked is_alive()
and then created + started the daemon thread without holding a lock, a
check-then-act race: two concurrent callers could both see "not alive"
and each spawn a thread. The loser's thread was never stored in the
module global and ran forever, un-joinable by the matching stop_*. Both
check-then-start sequences now run under a dedicated
_THREAD_LIFECYCLE_LOCK (kept separate from the purpose-bound
SESSION_CHANNELS_LOCK / _EMIT_COALESCE_LOCK), so exactly one thread is
ever created.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
BG_TASK_COMPLETE_EVENTS_SEEN gained a session_id -> set[process_id] entry the
first time a bg task completed for a session and was never deleted anywhere, so
it grew unbounded for the server lifetime.
The entry is created in _process_one for EVERY completion, whether or not any
SSE channel/tab exists, so pruning it only when the SessionChannel is reaped
would miss the dominant headless case (task fires, tab closed or never opened —
no channel to collect). Instead the reaper now sweeps the map by DELIVERY: once
a completion is drained (its session_id removed from PENDING_BG_TASK_COMPLETIONS)
the short _move_to_finished dedup window is closed and the entry is swept, every
tick, regardless of any channel. The registry's per-process_id
_completion_consumed gate remains the primary idempotency backstop, so sweeping a
delivered session's set can never resurrect an already-delivered completion.
Session deletion also prunes the entry (new forget_bg_task_completion_dedup),
covering a session deleted while a completion is still pending (which the
delivery-gated sweep deliberately retains).
Refs #4633
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
A visible tab can permanently miss a server-initiated turn (self-wake /
cron / restart hook) when its per-session SSE is momentarily down at the
emit instant. server_turn_started is a fire-and-forget broadcast with no
replay buffer; if the turn also finishes before the tab reconnects, the
on-subscribe self-heal finds no live run in ACTIVE_RUNS and replays
nothing, so the transcript stays stale until a hard refresh.
Extend the self-heal: the (re)subscribing tab reports its last-known
message_count (?known_count); when there is no live run to replay, the
handler compares the persisted count and, if the server is ahead, emits a
lightweight session-updated frame. The frontend syncs incrementally via
the #5189 keepStaleUntilLoaded swap-in-place loadSession path (no
clear+refetch, so the #5177/#5189 blank-gap jump is not reintroduced).
Idle-only and pane-scoped; emits only when the server is strictly ahead.
format_wakeup_prompt() in api/background_process.py returned None for any event
type other than 'completion'/watch_*, so async_delegation events (produced when
a background delegate_task subagent finishes) were silently dropped — the
subagent showed as perpetually 'running' and its consolidated result never
re-entered the parent conversation.
Add an async_delegation branch that delegates to the agent-side
tools.process_registry.format_process_notification (which already knows the
async_delegation shape), so the subagent result is rendered into the wakeup
prompt and re-enters chat. Scoped to async_delegation specifically (not all
unknown types) so genuinely-unrecognized events are still skipped — preserving
the existing skip-unknown-event contract.
Reported + root-caused by @mydelren.
Co-authored-by: mydelren <mydelren@users.noreply.github.com>
* stage bg_task trio combined (#2979 superset) on master for deep review
* fix(bg_task): unsubscribe SessionChannel on header-write failure (Codex deep-review catch) + regression test
* test: realign on-subscribe-recovery anchor to subscribe_to_session_channel after leak fix
* CHANGELOG: bg_task trio as v0.51.340 LD (HELD pending independent review)
* bg_task trio: apply 3 independent-review (greptile) fixes
1. start_session_turn now threads the session PROFILE model defaults
(_read_profile_model_config) into the wakeup model-resolve, so a brand-new
session with an empty model falls back to the profile default not global
DEFAULT_MODEL. Updated the white-box spy test signature accordingly.
2. /api/session/stream omits the Connection header (HTTP/1.1 keep-alive
default) to match the #3103 long-lived-SSE pattern.
3. Reaper now prunes _LAST_EMIT_TS for collected sessions so the coalesce
timestamp map can't grow one permanent entry per session forever.
nesquena APPROVED the PR; these are the 3 non-blocking greptile suggestions.
* test: realign _start_session_turn adapter stub lambda to new profile-defaults signature
ai-ag2026