When config.patch triggers a SIGUSR1 restart, two in-memory message
buffers were silently wiped:
1. Per-channel inbound debounce buffers (closure-local Map + setTimeout)
2. Followup queues (global Map of pending session messages)
This caused inbound messages received during the debounce window to be
permanently lost on config-triggered gateway restarts.
Fix:
- Add a global registry of inbound debouncers so they can be flushed
collectively during restart. Each createInboundDebouncer() call now
auto-registers in a shared Symbol.for() map, with a new flushAll()
method that immediately processes all buffered items.
- Add flushAllInboundDebouncers() which iterates the global registry
and forces all debounce timers to fire immediately.
- Add waitForFollowupQueueDrain() which polls the FOLLOWUP_QUEUES map
until all queues finish processing (or timeout).
- Hook both into the SIGUSR1 restart flow in run-loop.ts: before
markGatewayDraining(), flush all debouncers first (pushing buffered
messages into the followup queues), then wait up to 5s for the
followup drain loops to process them.
The ordering is critical: flush debouncers → wait for followup drain →
then mark draining. This ensures messages that were mid-debounce get
delivered to sessions before the gateway reinitializes.
Tests:
- flushAllInboundDebouncers: flushes multiple registered debouncers,
returns count, deregisters after flush
- createInboundDebouncer.flushAll: flushes all keys in a single debouncer
- waitForFollowupQueueDrain: immediate return when empty, waits for
drain, returns not-drained on timeout, counts draining queues
- run-loop: SIGUSR1 calls flush before markGatewayDraining, skips
followup wait when no debouncers had buffered messages, logs warning
on followup drain timeout
