* spawn: kill process group + heartbeat subagent activity
two compounding bugs produced zombie agent runs that stalled until the
GitHub-Actions job-level timeout (observed on PR #622, run 25577068620).
1. SIGKILL hit the wrong process. node_modules/opencode-ai/bin/opencode
is a Node shim that spawnSyncs the native opencode-<plat>-<arch>
binary with stdio:"inherit". our spawn() ran without detached, so
child.kill("SIGKILL") killed only the shim. the native binary was
reparented to PID 1, kept holding our stdout pipe via inherited fds,
and child.on("close") never fired — leaving the agent promise
pending past the 5min outer safety-net timer ("agent still pending
5min after inner activity kill — forcing exit") and the grandchild
running until the runner timed out.
fix: SpawnOptions gains killGroup; when set, we spawn detached and
route all kill paths (timeout, activity timeout, ctrl-c) through
process.kill(-pid, signal). opencode + claude opt in.
2. inner activity timer false-fired during long task subagents.
opencode's `task` tool encapsulates subagent execution in-process —
subagent-internal events don't reach the parent NDJSON stream — so
the parent looked idle for the full subagent duration even when
real work was happening, and the 5min DEFAULT_ACTIVITY_TIMEOUT_MS
would fire mid-subagent.
fix: SpawnOptions gains externalActivitySource; the timer fires on
min(local stdout idle, external idle). opencode passes getIdleMs()
from the global activity tracker and runs a 30s heartbeat
(markActivity()) while at least one task dispatch is in flight.
action/utils/subprocess.test.ts covers both: a bash+sleep grandchild
that proves close fires <10s with killGroup, and externalActivitySource
keeping the timer armed during 8s of stdout silence.
* opencode: suspend activity timer instead of heartbeat during subagent runs
addresses review on prior commit: replace the 30s markActivity()
heartbeat with a boolean isPausedExternally predicate keyed off
opencode's existing taskDispatchByCallID + pendingTaskDispatches.
no fake activity, no race window between a 30s tick and a subagent
that finishes between ticks.
while the predicate returns true, spawn's activity check skips the
kill decision *and* advances lastActivityTime so a clean unpause
can't fire on a stale baseline. tests cover both the suspended case
(8s of stdout silence + activityTimeout=1s but paused → process
exits cleanly) and the resume case (paused for 500ms then unpaused
→ 30s sleep gets killed by activity timeout as normal).
Colin McDonnell
ca913c76ea