The worker-thread watchdog from #856 didn't work in the real daemon — caught by
live-testing against a real serve --mcp. V8 isolates coordinate on global
safepoints, so a main thread wedged in a tight non-allocating loop (#850's
SourcePositionTableIterator::Advance) strands the watchdog worker before it can
SIGKILL.
A separate child process shares no isolate/heap with the parent, so the wedge
can't touch it; it kills via the kernel. Parent heartbeats to the child's stdin;
silence past the timeout -> SIGKILL; parent exit closes the pipe -> child exits.
Validated live (real daemon SIGKILLed in ~timeout); regression test covers the
non-allocating-wedge-under-heap-pressure case. API/install points/CHANGELOG
unchanged; the broken worker version was never released.
Belt-and-suspenders follow-up to #855. Any non-yielding sync loop on the main
thread wedges the event loop, and nothing running on that loop (timers, signal
handlers, PPID watchdog) can recover it — only another thread can.
A tiny worker thread (in the detached daemon + direct modes) watches a
shared-memory heartbeat the main thread bumps each event-loop turn; if it stops
advancing across enough consecutive checks (~CODEGRAPH_WATCHDOG_TIMEOUT_MS,
default 60s) the worker SIGKILLs the process so a fresh daemon starts on the next
connection. Counts consecutive stale checks (not wall-clock) so it's immune to
clock jumps / sleep; tuned never to fire on real work; opt out with
CODEGRAPH_NO_WATCHDOG=1.
Colby MchenryandGitHub