The subprocess-booting test suites hand-picked fixed ports in a cramped ~3955-4021 range, and
156-schedule-read-path deviated to a RANDOM port (3900 + rand%90) that overlapped those fixed
ports. Under CI load two servers could race on the same port, surfacing as flaky "no such table:
devices" / "FOREIGN KEY constraint failed" (a server answering a request against a half-migrated
or wrong DB). It's environmental — the suites pass locally and in isolation.
Fix: a shared test/helpers/free-port.js (bind :0 on loopback, read the OS-assigned port, release)
called in before() so every suite gets a guaranteed-unique ephemeral port — concurrent suites can
no longer collide, and no one has to hand-assign ports.
- Codemod converted 30 suites: const PORT = <fixed|random> -> let PORT (+ BASE) assigned via
`PORT = await freePort()` at the top of before().
- 3 hand-fixed (different structure): 148-eviction-storm (lowercase `base`), boot-health (no
before() — allocates PORT + a throwaway SEED_PORT inside the test, replacing the hardcoded
3894), totp-keyrotation (no before() — allocates at the test start before bootServer()).
No fixed 39xx/40xx ports remain. Full server suite 435/435; the 4 hand-touched suites pass in
isolation. Pure test-infra change — no app code touched.
Item 2: when the heartbeat checker marks a device offline it now also disconnects any socket
it still holds for it, so DB-offline can't diverge from socket-state into a silent half-open
(defensive — the live-socket guard already defers genuinely-live sockets).
Item 3: tighten half-open detection WITHOUT reintroducing the TV-WebKit decode-load risk the
30s pong-timeout was chosen for — lower only pingInterval 30s->15s (probe more often), KEEP
pingTimeout at 30s. Detection = interval+timeout = 45s (was 60s), and the client inherits
these via the handshake so BOTH ends detect a dead peer ~25% sooner. (Deliberately did NOT
drop pingTimeout to ~20s: MAXHUB is a video-playing TV-class device and the code comment
warns tighter timeouts cause spurious drops under decode load.)
Item 4: SO_KEEPALIVE on every accepted connection (lib/tcp-keepalive.js) so a half-open TCP
can't persist indefinitely at the OS layer, independent of the app ping.
Tests: server closes a non-ponging peer within ~pingInterval+pingTimeout while a ponging peer
survives; a device whose transport dies ends offline with its connection torn down; keepalive
applied to each accepted connection (and never breaks setup on error). Suite 328/328.
