iOS client inbox is not in sync with web client.

[m-natarajan]

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Version Number:
Reproducible in staging?: Needs reproduction
Reproducible in production?: Needs reproduction
If this was caught during regression testing, add the test name, ID and link from TestRail:
Email or phone of affected tester (no customers):
Logs: https://stackoverflow.com/c/expensify/questions/4856
Expensify/Expensify Issue URL:
Issue reported by: @muttmuure
Slack conversation: https://expensify.slack.com/archives/C05LX9D6E07/p1719833472233469

Action Performed:

1. Log to iOS and web with high traffic account
2. In iOS approve or pay any iou
3. Send a message as user B to A and read the message in iOS

Expected Result:

Both iOS and Web client are updated in real time when reading the message or approving a report

Actual Result:

iOS not synching with web

Workaround:

unknown

Platforms:

Which of our officially supported platforms is this issue occurring on?

• Android: Native
• Android: mWeb Chrome
• iOS: Native
• iOS: mWeb Safari
• MacOS: Chrome / Safari
• MacOS: Desktop

Screenshots/Videos

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[melvin-bot]

Current assignee @muttmuure is eligible for the Bug assigner, not assigning anyone new.

[melvin-bot]

Triggered auto assignment to @lakchote (AutoAssignerNewDotQuality)

[m-natarajan]

#44683

[lakchote]

Unable to reproduce, I've posted details on reproduction steps here. Tests done on new staging version deployed yesterday.

[lakchote]

Asked for a way to reliably reproduce it here, as I haven't been able to.

[lakchote]

@muttmuure do you still encounter the problem or not?

[muttmuure]

Yes, unfortunately I don't think we've fixed the root cause of this

[lakchote]

Asked for external expert help here, to speed up the resolution.

[lakchote]

@jnowakow will help on this one.

[muttmuure]

@jnowakow can you comment on the issue and I'll assign you?

[jnowakow]

Hello, sorry for late response. You can assign me to this one :)

[SzymczakJ]

Since Jan has some other work to finish, I will be taking over this issue, can you reassing it to me?

[muttmuure]

done

[SzymczakJ]

I can't reproduce this issue(even on high traffic account and with lots of messages unread), is this something that happens every time on your account, or maybe this bug happens after some time, or maybe it seems random and happens only from time to time?

[lakchote]

I can't reproduce this issue(even on high traffic account and with lots of messages unread), is this something that happens every time on your account, or maybe this bug happens after some time, or maybe it seems random and happens only from time to time?

That's the tricky part, I wasn't able to reproduce either.

From what @muttmuure told me, it doesn't happen every time which complicates the reproduction steps.

[muttmuure]

I think that what might be happening is that on poor connections Ping and ReconnectApp are causing the sequential queue to break/flush and we're dropping updates when the connection is live again. This means that your mobile app will have a list of chats that were meant to be updated but were not.

There is a PR to fix this: #44269

Let's see if fixing Ping and ReconnectApp fixes this, if it doesn't then we'll need to consider why getting the Onyx updates is failing

[SzymczakJ]

Tried to reproduce for about 2 hours and failed to do so. I'll try once more when #44269 fails to fix this issue. Is it okay with you?

[muttmuure]

I wonder if we can reproduce this with these steps

Receive messages to iOS

Go offline on iOS

Create a queue of 11 failed Pings/ReconnectApp back to back using network throttling

Queue a successful Ping/ReconnectApp

Mark the message as read on web (maybe we should try this during the failing network requests on mobile too?)

See if the status syncs over

[SzymczakJ]

I'll try these steps as a first thing on Monday, because today all of SWM is leaving for a integration trip and I'm working shorter hours 😃

[lakchote]

@SzymczakJ will test this morning if the reproduction steps above are working or not.

PR that possibly fix this is still open.

[SzymczakJ]

Tried these reproduction steps and everything seems to work fine.
Clamped sequential queue with 13 failed ReconnectApp requests, then went back to online on iOS and read the message on web.
App flushed the sequential queue and when queue length became 0 iOS synced successfully with web.
Maybe let's wait for that PR that Lucien mentioned? WDYT?

[muttmuure]

Can we try reading the message during the series of failed ReconnectApp requests?

[SzymczakJ]

I've read the message when iOS was going over all the stacked ReconnectApp requests. Initially the message wasn't shown as read on iOS, only after the App made a successful ReconnectApp request the message got updated and became "read".
The message finally got it's status updated so I think this is a correct behaviour

[muttmuure]

OK, so it's something else then - thanks for looking.

[melvin-bot]

@lakchote @muttmuure @SzymczakJ this issue was created 2 weeks ago. Are we close to a solution? Let's make sure we're treating this as a top priority. Don't hesitate to create a thread in #expensify-open-source to align faster in real time. Thanks!

[lakchote]

We're not close to a solution since we can't reproduce the bug reliably.

Other cases of a sync problem happening:

• https://expensify.slack.com/archives/C05LX9D6E07/p1721229329178199
• https://expensify.slack.com/archives/C05LX9D6E07/p1721229329178199 (reverse case here - it's Web not in sync with iOS)

@SzymczakJ were you able to reproduce it at least once or not?

Asked in #expensify-open-source if someone has encountered the same problem already or not, to see if we can deduce the steps to reproduce the bug.

[muttmuure]

I'm concerned that this still happens, but without reproduction steps it's hard to know how to proceed

[muttmuure]

I think that this is caused by the Clear Cache and Restart tool in the Troubleshoot menu.

If you use that tool, your updated LHN is not synced across devices (which makes sense) and so it seems like they are out of sync (but that has been forced)