Asked for directly: "same account, same device already in the party"
should never need a confirmation, "same account, a genuinely different
device" should ask before disconnecting it instead of silently
overwriting. There was no concept of "device" at all before this -
party.members is keyed by userId only.
- client/src/deviceId.ts (new): a UUID kept in localStorage (not
sessionStorage) - that's what makes "device" mean "browser", not
"tab". Falls back to an in-memory id if storage is unavailable.
- server/src/types.ts, client/src/api/party.ts: "join" now carries
{partyId, deviceId, force?} instead of just {partyId}; new
PartyMember.deviceId and "deviceConflict" server->client event (sent
only to the joining socket, never broadcast).
- server/src/realtime/SocketGateway.ts: the "join" handler now tells
three cases apart - no existing connection or the same deviceId
reconnecting (attach silently, booting any stale connection for that
same device first), a different deviceId with no force (emit
deviceConflict and stop - the socket stays connected but inert), or
force:true (the confirmed takeover - boot the old connection, take
the slot).
- server/src/services/PartyService.ts: join() is now idempotent -
returns the existing member instead of always building a fresh one.
This was itself a real bug independent of the guard below: the REST
"Rejoindre" route calls this every time regardless of membership, so
a re-click/reload/retry used to silently reset connection/isPaused/
deviceId.
- server/src/realtime/SocketGateway.ts: "leave"/"disconnect" now also
check party.members.get(userId)?.connection === socket before acting
- generalizes the earlier stale-connection crash fix to the new
reality where a member can have more than one connection attempt in
flight (the superseded one's own eventual "disconnect" must not be
read as a real leave).
- client/src/views/player/Player.ts, client/src/musicBar/MusicBar.ts:
onDeviceConflict wired to a plain confirm() - yes calls the new
PartyConnection.confirmDeviceTakeover() (re-sends "join" with
force:true), no backs out (navigate home for video, leaveMusicParty
for music).
- Deliberately does NOT change the home page's live party list itself
(still just "Rejoindre" either way) - LobbyPartyDto is one snapshot
shared by the whole "lobby" room with no per-viewer membership info,
and giving it that is a real protocol change on its own. For video
the conflict check above already is the meaningful moment (you can't
be looking at the home page from inside your own party on the same
tab - the player is a full-screen takeover), so this doesn't cost
the feature much: Rejoindre reaches the check immediately, same
device reconnects silently, a different device asks first. See
docs/architecture.md for the fuller reasoning.
- server/test/socketGateway.test.ts, server/test/partyService.test.ts:
new tests for the conflict/takeover/reconnect paths and join()'s
idempotency; the earlier stale-connection crash regression test
updated to reach the same shared-slot shape through a real device
takeover instead of a raw PartyService.join() call (which no longer
reproduces it now that join() is idempotent).
Verified: full typecheck+test+build on both projects (39/39 server
tests passing); confirmed the "leave"/"disconnect" guard is load-
bearing by temporarily reverting it and watching the new takeover test
fail, then restoring it; deviceId.ts's localStorage persistence
checked against the real compiled bundle in a real browser (survives
a reload, stable across calls).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>