Found in the alpha load test: client-chosen pairing codes collide by birthday
paradox, the provisioning INSERT hit UNIQUE(devices.pairing_code), the SqliteError
threw out of the (synchronous) socket handler -> uncaughtException -> logFatalAndExit
-> the WHOLE server exited and every device dropped. The colliding flood crash-LOOPED
the container (2 restarts).
Two layers, same "one device can't take down the fleet" theme as #142/#143/#144:
1. Narrow (deviceSocket.js): wrap the device:register provisioning INSERT in
try/catch — a UNIQUE pairing_code collision (or ANY db error) rejects THAT
registration (device:auth-error -> client retries) instead of throwing.
currentDeviceId/authenticated now set only AFTER the row exists (no half-auth
socket on failure).
2. Broader (lib/safe-socket.js): protectSocket() overrides socket.on per connection
so any handler throw is caught, logged (event + id + stack), the socket told, and
DISCONNECTED — per-CONNECTION fail-fast, not whole-PROCESS. We don't keep serving a
connection from possibly-half-mutated state (honors the existing fail-fast intent),
we just contain it to "one device reconnects" (a non-event after beta5). Wired into
both the /device and /dashboard connection handlers; auto-covers future handlers.
Audited first: no handler throws as control flow, so blanket-wrapping is safe.
Tests (mutation-verified, fail without their fix):
- register-insert-crash.test.js: a pairing_code collision AND a general bind error
each reject-one-device with no uncaughtException; server keeps serving.
- socket-handler-isolation.test.js: a throwing handler disconnects only that socket;
the server + other sockets stay alive.
Full suite 243/243.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
