0013. Reconnecting yields a fresh socket, not the old one

Status: Accepted · 2026-07-28 · #67

TL;DR client.connect() after a disconnect produces a new server socket with a new id and no previous room membership; calling connect() while already connected is a no-op. This matches real socket.io.

Decision

Reconnecting a client with client.connect() pairs it with a brand-new server socket that has a new id and none of the socket's previous room memberships. It does not revive the old socket or restore old rooms. Calling connect() on an already-connected client does nothing, matching real socket.io-client.

This was verified against real socket.io: a reconnect there is a new session, not a resumed one, so the fresh id and empty rooms are the reference behaviour rather than a simplification smocket chose.

Related and observable: on disconnect the socket's rooms set is emptied in place, not replaced with a new set. A caller holding a reference to that set sees it become empty, which the contract pins as observable, so the in-place clear is a decision and not an implementation detail free to change.

Alternatives rejected

• Reuse the previous socket and id on reconnect. Convenient, but real socket.io issues a new session, and reusing the id would make smocket disagree with the reference on the very thing a reconnect test checks.
• Auto-rejoin the previous rooms. A client may want that, but socket.io does not do it automatically, so membership after reconnect starts empty.