0037. Keep broadcast management local and canonical

Status: Accepted · 2026-08-14 · #265, #322, #323, #324 Governed by: 0000, 0019, 0025, 0028, 0036

TL;DR Smocket implements local fetchSockets, socketsJoin, and socketsLeave, and disconnectSockets, while deferring deprecated allSockets. Management selects canonical local Sockets; delivery adapters do not redefine the set.

Decision

Socket.IO 4.7.5 and 4.8.3 behaved alike. fetchSockets respected room union and exclusions and returned the existing local Socket objects. Bulk join and leave mutated the selected sockets synchronously. disconnectSockets(false) stayed in the selected namespace, while true closed every namespace Socket sharing a selected Socket's Manager. Every bulk method returned undefined. allSockets was deprecated and ignored exclusions in both versions.

Smocket implements fetchSockets, socketsJoin, socketsLeave, and both forms of disconnectSockets. It defers allSockets instead of adding a deprecated API whose compatibility requires preserving an exclusion quirk.

Accepted methods use the namespace roster and each Socket's actual rooms. Target rooms form an ordered, deduplicated union; exclusion rooms and the sender's id-room are then removed. A custom SmocketAdapter.socketsIn result may change event routing, and a DroppingAdapter may remove final event recipients, but neither changes management. Timeout, volatile, compression, tracing, and delivery scheduling flags are also ignored.

fetchSockets resolves existing local server Socket objects. Its public fetched-socket type carries the broadcast event map and socket-data generic while promising the stable Socket.IO subset: identity, handshake, rooms, data, emit, join, leave, and disconnect. There is no remote-Socket or serialization promise.

Bulk membership snapshots the selected Sockets, then delegates to their existing join or leave primitive. Mutating a room used for selection therefore still reaches every Socket in the original set, and each call returns undefined synchronously.

Bulk disconnect also snapshots selection. false delegates namespace-local teardown; true delegates Manager teardown from 0028, including unselected namespace siblings and pending admission. Existing lifecycle guards keep each affected Socket single-shot.

These operations are local-only. Redis adapters, clusters, remote Socket values, and multi-server coordination remain outside scope. Adding this newly covered Socket.IO surface is a minor release after v1 and a patch before v1 under 0019.

Alternatives rejected

• Implement allSockets. Deprecation plus its exclusion quirk adds liability without a capability fetchSockets cannot provide.
• Route management through the registered adapter. Smocket adapters are a narrower, transport-free delivery seam; making them own membership or lifecycle would reverse 0025.
• Apply deterministic drops to management. Decision 0036 limits drops to broadcast event delivery, not management selection.
• Return copied Socket views. The measured local result is the existing Socket object; copying would break identity and make mutations diverge.