[BUG] Inaccurate error message in reserveSeatFor when an IPC timeout occurs

[eugene-egorov]

We intermittently see a “room is already full” error in production. We don’t explicitly lock the maxClients value, so I suspect the actual cause is an IPC timeout (likely related to #876 ). The problem is that reserveSeatFor throws the same “room is already full” error in both cases, so we can’t distinguish between them and adjust client behaviour accordingly.

colyseus/packages/core/src/MatchMaker.ts

Line 739 in 7a8326d

throw new SeatReservationError(`${room.roomId} is already full.`);

[endel]

Hi @eugene-egorov, thank you for reporting - I'm trying to isolate this issue locally - any tips how we could try to reproduce it?

Is .joinOrCreate() calls that are causing this? Which version of @colyseus/core are you currently using?

[eugene-egorov]

@endel I’m currently facing this issue with the joinById call in 0.15, and I believe it occurs in 0.16 as well—the IPC logic there is mostly the same.

To reproduce, I built a small chaos proxy in front of Redis; the proxy can time out and drop messages in pub/sub.

I can publish the repro later.