A consumer's clean-room verification of the 8.0.10 fix found relate() still
hanging their scripts. Root-causing the CLASS instead of the repro found two
mechanisms:
1. The 'beforeExit' auto-flush hook looped forever on any script that never
reaches close(): Node re-emits beforeExit after every event-loop drain, and
the async flush schedules new work — flush, drain, flush, forever. The
listener now self-deregisters BEFORE its one flush, so the next drain exits.
(Empirically: process.on('beforeExit', async () => await anything) alone
never exits — this was the deepest root of the whole hang class.)
2. Every background-maintenance interval is now unref'd at creation — graph
auto-flush, LSM compaction, metadata write-buffer flush, VFS cache
maintenance, PathResolver cache maintenance, statistics debounce (the
writer-lock heartbeat, flush watcher, and cache monitors already were).
Durability is owned by close() and the beforeExit flush, both deterministic;
a best-effort interval must never keep the host process alive.
Proof: the reported shape (add x2 + relate, filesystem) exits cleanly BOTH
with close() (~0.5 s) and with NO teardown at all — and in the no-teardown
case the beforeExit flush still lands the data (verified by reopen: both
nouns + the edge present). New per-op-class sweep test asserts no ref'd
timer survives close() for add / relate / graph find / metadata update /
vfs — turning this bug class off permanently instead of per-repro.
David Snelling
30eacbdfeb