Bug: [New Expensify] Unread message shows as bold in the LHN but green line does not appear reported by @gadhiyamanan

[kavimuru]

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Action Performed:

1. Send a message when receiver is not logged in
2. log into the receiver account
3. Check the message

Expected Result:

Both in the LHN and in the chat shows New message indicator

Actual Result:

No new message indicator inside the chat, only in the LHN it shows as bold as new message indicator

Workaround:

Unknown

Platform:

Where is this issue occurring?

• Web
• iOS
• Android
• Desktop App
• Mobile Web

Version Number: 1.2.12-3
Reproducible in staging?: y
Reproducible in production?: y
Email or phone of affected tester (no customers):
Logs: https://stackoverflow.com/c/expensify/questions/4856
Notes/Photos/Videos:
https://user-images.githubusercontent.com/43996225/195195728-9396a493-a85d-48b3-90ba-b8dc7d876f2b.mp4
https://user-images.githubusercontent.com/43996225/195195752-26184b12-3057-40dc-bac5-e3e67d76a1ff.mov
Expensify/Expensify Issue URL:
Issue reported by: @gadhiyamanan
Slack conversation: https://expensify.slack.com/archives/C01GTK53T8Q/p1665479496661839

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[melvin-bot]

Triggered auto assignment to @slafortune (AutoAssignerTriage), see https://stackoverflow.com/c/expensify/questions/4749 for more details.

[slafortune]

Reproduced on slafortune@expenisfy.com
New Expensify
Version 1.2.13-3 (1.2.13-3)
Desktop App

While the message is bolded indicating a new message was sent - the unread message does not show the “NEW” green line above the unread message.

I was not logged into New Expensify when the message was sent -
Notice the name is bolded and has no green line and New -

I was logged into New Expensify but not my active window when the message was sent -
Notice the Green line and New and the Name not bolded - I was not logged out of New Expensify

[slafortune]

Also - similar issue is reported here -#10736

[melvin-bot]

Triggered auto assignment to @marcaaron (Engineering), see https://stackoverflow.com/c/expensify/questions/4319 for more details.

[marcaaron]

This is a pretty frustrating one. Gonna take it internal so we can design and fix it properly, but here's why it happens:

• We are using componentDidUpdate() to detect that a "new action has arrived" by looking at the last action and comparing it to the latest here:

App/src/pages/home/report/ReportActionsView.js

Lines 179 to 180 in d0f0dd5

	const didNewReportActionAppear = previousLastSequenceNumber !== currentLastSequenceNumber;
	if (didNewReportActionAppear) {

• We then update the newMarkerSequenceNumber to 0 because we are scrolled to the bottom of the chat

That is the correct behavior when you are already looking at the chat. But doesn't really work as expected when you:

• visit a chat
• fetch more recent actions
• component updates and processes a "new action" as if it has just arrived in realtime

Said another way, we are making a really bad assumption that a "new action appeared" when we only look at the componentDidUpdate() data changing. A general solution here would be to only allow the componentDidUpdate() logic to run when a "new" report action actually appears and not just some are loaded from the server when the component mounts. But I think in that case we're better off just moving it all out of the component entirely to avoid any confusion.