Reconnect sync does not refresh open thread and infinite message lists on DDP-only reconnects

[VanshajPoonia]

Description

Reconnect message synchronization reconciles the main message list but not the thread panel or the infinite message list queries. After a reconnect where a message was edited or deleted while the client was offline, an already open thread or list can keep showing the stale version until that view is reopened.

Where it comes from

useLoadMissedMessages reconciles the Messages store when the connected state goes from false to true. The main room message list reads from that store, so it updates correctly.

The thread panel (useThreadMessagesQuery) and the infinite message lists (useInfiniteMessageQueryUpdates, used by discussions, the threads list and omnichannel history) keep their own React Query caches that are only fed by live room-messages and notify-room/deleteMessage / deleteMessageBulk stream events. Those streams do not replay what was missed while offline.

React Query's refetchOnReconnect default does refresh these caches, but only when its online manager fires, which is driven by the browser navigator.onLine offline/online events (see apps/meteor/client/lib/queryClient.ts, which keeps the default). So a plain network drop is covered.

When it is visible

It shows up on a DDP socket reconnect that does not come with a browser online event, for example a server restart, a proxy blip, or laptop sleep/wake where the socket dropped but the OS still reported online, while a thread or list was open the whole time.

Steps to reproduce

1. Open a thread in a room
2. Keep the client running but drop only the DDP connection (for example restart the server) so the browser never fires an offline event
3. From another user, edit or delete a message inside that thread while the first client is disconnected
4. Let the first client reconnect
5. The main message list is correct, but the open thread still shows the old content until it is closed and reopened

Suggested direction

Reconcile the affected React Query caches on the same reconnect edge, so threads, discussions, the threads list and omnichannel history are refreshed together rather than each relying on the browser online signal. Worth deciding how broad the invalidation should be to avoid refetching every open list on every reconnect.

References

• Reconnect sync migration to GET /v1/chat.syncMessages: Performance/Refactoring: Migrate reconnect message synchronization from DDP loadMissedMessages to REST syncMessages with index optimizations #41079
• The ddp-removal TODO that moved reconnect off loadMissedMessages: (ddp-removal): this should move to /v1/chat.syncMessages so reconnect #41000
• Reconnect sync and store reconciliation: apps/meteor/client/views/root/hooks/useLoadMissedMessages.ts
• Thread panel cache fed only by streams: apps/meteor/client/views/room/contextualBar/Threads/hooks/useThreadMessagesQuery.ts
• Infinite list caches fed only by streams: apps/meteor/client/hooks/useInfiniteMessageQueryUpdates.ts
• Query client defaults (refetchOnReconnect left at default): apps/meteor/client/lib/queryClient.ts

[coderabbitai]

🔗 Related PRs

#40616 - regression: restore reactive ConnectionStatusBar updates during reconnection [merged]
#40954 - chore: reduce room opening latency in message history load [merged]
#40956 - fix: thread panel not scrolling to bottom after sending a reply [merged]
#40981 - chore: undo loadMissedMessages deprecation from #40711 [merged]
#40991 - fix: retry transient errors when opening a room [merged]

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[dikshabj]

Hi! I've been looking into this issue and traced the reconnect flow.

From what I understand, useLoadMissedMessages reconciles the main message store after reconnect, but the React Query caches used by the open thread and infinite message lists don't appear to be refreshed, which matches the behavior described in the issue.

My current thought is to invalidate/refetch the affected React Query caches on the reconnect path (instead of relying only on the browser's online event), while keeping the scope limited to avoid unnecessary refetches. I'm still verifying the best place to do this.

If this direction sounds reasonable and no one is already working on it, I'd be happy to work on it.

[VanshajPoonia]

@dikshabj I already opened a PR, would you mind contributing to the same PR?

[dikshabj]

@VanshajPoonia Sure, I'd be happy to contribute!

I was looking into the React Query cache reconciliation mentioned in #41190. I'll go through your PR and see where I can help. If there's a specific part you'd like me to work on, let me know.