0.5.2: dedup stale + dual-dial sessions in addPeer / inbound-connection

[sym-bot]

Summary

Three failure modes collapsed into the same bug: the prior dedup logic in inbound-connection and _createPeer short-circuited the moment a same-source transport key was present in peer.transports, regardless of whether that prior was actually alive or what direction it was in.

1. Stale prior — the previous transport's _closed flag is set but its close handler hasn't fired yet. Apple's Network framework doesn't always deliver FIN promptly when a peer process exits abruptly (especially on same-host LAN connections). Any reconnect attempt was permanently rejected until the OS reaped the dead entry.

2. Same-direction duplicate — listener fires newConnectionHandler twice for the same advertised service (TCP retry, multipath race, repeated Bonjour resolution). Silently replacing the established healthy inbound with the duplicate tears down the wire pair on the remote side → peer-left storm.

3. Dual-dial collision — both peers Bonjour-discover each other within ~50ms and both initiate outbound TCP. The unconditional reject killed one side's view of the connection, leaving asymmetric peer state.

Field evidence

Observed on macOS: Mac MeloMove (Catalyst, sym-swift v0.3.80) and claude-code-mac (Node, this SDK) on the same Mac would never maintain a peer relationship. claude-code-mac silently rejected Mac MeloMove's inbound dial via the transport.close(); return; short-circuit at lib/node.js:512 (pre-fix). iPhone↔claude-code-mac across the LAN worked because the timing windows differ — claude-code-mac's outbound to iPhone landed first as iPhone's inbound, no dedup conflict.

Mac MeloMove log:

[SYM] session: connection ready (outbound=true)
[SYM] session: disconnected: Connection closed     ← claude-code-mac closed it
[C1 019d59a1-...] is already cancelled, ignoring cancel

Fix

In both inbound-connection handler and _createPeer:

• Detect stale prior (_closed=true) and treat as no prior.
• For same-direction duplicate: keep prior, drop new (no wire-pair teardown on the remote).
• For dual-dial: nodeId-based deterministic tie-break (lower nodeId acts as client, keeps outbound; higher keeps inbound). Both peers independently compute the same physical-socket winner without exchanging coordination frames.

This mirrors the @sym-bot/sym-swift v0.3.80 fix that landed earlier today, so cross-runtime peers now agree on the same dedup convention.

Tests

150/150 existing unit tests pass — no regressions in transport priority, peer lifecycle, multi-transport, or any other path.

Test plan

• All existing unit tests pass (npm test)
• Verify on Mac MeloMove ↔ claude-code-mac (same host) — connection establishes and stays connected; claude-code-mac shows up in Mac MeloMove's PEERS list.

🤖 Generated with Claude Code