Development Update — May 13

The day after the v1.3.53 ship: most of the work is on the chat-app’s subscriber-liveness model. Four flags collapse into one, and a watchdog plus a fan-out fix shake out the remaining false negatives on subscriber_alive.

Skywire: Skychat/Group — Unified Liveness Signal

PR #2537 is the cleanup: four separate liveness fields collapse into a single lastInboundNs (atomic int64, set on every observable inbound event). The old fields were:

• Session.subAlive bool — toggled on Connect / Close
• Session.lastHeartbeatNs — heartbeat-only signal
• Record.LastMessageAt — chat-only, persisted
• Record.Status — configuration state pulling double duty as health

They kept disagreeing. Each pair-wise disagreement got its own fix (PRs #2530–#2534 in this same arc) and the holistic answer was a single timestamp that’s computed from events instead of stored in multiple places.

Post-refactor:

• IsSubscriberAlive() is a pure function of lastInboundNs and a closed flag.
• detectStaleAndReconnect is the recovery driver — kicks reconnect on stale sessions.
• Persisted LastMessageAt survives only as a crash-recovery seed.

Skywire: Skychat/Group — Owner Heartbeat Watchdog

2531 feat(skychat/group): owner heartbeat watchdog for fast stale-sub detection — without a heartbeat, a member’s subscriber would stay “fresh” indefinitely between chat messages on a quiet group. The owner emits a __skychat_group_heartbeat__ marker on a 30-second cadence; subscribers observe it as a normal inbound (bumping lastInboundNs) but filter it out before fan-out to the user-visible inbox.

Result: a quiet group’s subscriber_alive stays accurate (~3× heartbeat interval staleness window), without polluting the chat history with heartbeat noise.

Skywire: Skychat/Group — Heartbeat / Delivery / Stale-Active Followups

Four small but load-bearing fixes:

• 2530 fix(skychat): /status groups visibility + stale-active demotion + inbox MarkMessage — /status was hiding groups with status=stale, and Status=Active survived even when liveness was clearly dead. Demote to stale on the next tick when IsSubscriberAlive returns false.
• 2532 fix(skychat/group): re-assert subAlive on every delivered message — required because the unified signal collapse was still in flight and the old subAlive flag could drift.
• 2534 fix(skychat/group): flip subAlive on heartbeat observation too — the heartbeat path was bypassing the alive-flip because it routed through a different fan-out branch.
• 2538 fix(cxo/node): bounded sendMsg + fan-out broadcastRoot — closes F11b — a CXO-layer fix that fed into this work. The publisher’s broadcast path was unbounded; a slow consumer could backpressure the publisher’s send loop and stall heartbeat publishing. Bounded send queues + drop-on-full semantics prevent the cascade.

Skywire: Skywire-Autoconfig — Persistent skywire.conf Edits

2536 feat(skywire-autoconfig): persistent skywire.conf edits + cleanup vestigial knobs — autoconfig used to regenerate /etc/skywire.conf on every run, blowing away operator-edited knobs. Now autoconfig parses the existing file, applies its computed updates, and writes back without touching unrelated fields. Also drops a handful of long-dead knobs (USE_KADEMLIA, DHT_PORT, etc.) that nothing reads anymore.

Skywire: CLI/Config — LANDMSG Defaults

2535 feat(cli/config): LANDMSG defaults to ISHYPERVISOR + add LANDMSGPORT — LANDMSG (the local-address DMSG port for the visor’s own dmsg-server-side accept) had no default; visors that needed it had to set it explicitly. Now it defaults on when the visor is a hypervisor (the only common case where the local-address dmsg matters). The new LANDMSGPORT knob lets operators choose a port; defaults to a derived value.

Skywire: Misc

• 2562 fix(visor/cat): release dialCtx synchronously after dial, not via defer — the deferred release was holding the context past the function return, leaking until GC.
• 2563 fix(cli/config): seed conf-service PK in dmsg entry cache before fetch — a chicken-and-egg where the dmsg cache fetch required the entry it was trying to seed.
• 2564 perf(stats/cxo): batch sample writes into a single Publisher mutex acquire — same mutex contention pattern as PR #2495, applied to the stats sampler.
• 2565 fix(cli/proxy): honor ctrl+c during --verbose startup; accept positional <pk>.
• 2566 perf(cxo): coalesce publisher tree-walk writes into one bbolt tx. The tree-walk used to issue one bbolt transaction per leaf; coalescing into a single tx per walk drops fsync overhead substantially on busy publishers.
• 2567 perf(transport): centralize per-transport tickers in Manager — instead of every transport spinning its own ticker goroutines, the manager runs one ticker for the whole set.
• 2568/6e256fd4e fix(skychat/sse): replay buffer + 0-subscriber drop visibility — the SSE hub was dropping messages when no subscribers were connected, with no counter visibility. Now the drops feed /status.sse_drop_count.
• 2569 feat(dmsgpty-host): TCP-only / shared-SK / socket-activation for sshd-style daemon — standalone dmsgpty-host gains the ergonomics of a real sshd: socket-activated under systemd, can use shared identity keys, and can serve a TCP listener directly (no dmsg needed) for trusted local-network use cases.