[Due for payment 2025-11-12] [$250] API - Duplicate ReadNewestAction API call for new messages

[mitarachim]

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Version Number: v9.2.32-0
Reproducible in staging?: Yes
Reproducible in production?: Yes
If this was caught during regression testing, add the test name, ID and link from BrowserStack: https://test-management.browserstack.com/projects/2219752/test-runs/TR-1305/folder/13176688/52080502/955759034
Email or phone of affected tester (no customers): htad26+eriuiyui@gmail.com
Issue reported by: Applause Internal Team
Device used: Windows 10/Chrome
App Component: Other

Action Performed:

Preconditions
User A and User B already have a chat history

1. As User A, ensure the currently opened chat screen is not the chat report with User B
2. As User B, send a message to User A's chat report
3. As User A, wait until the message has been received
4. As user A, open the browser's Network tab > Filter the network traffic for the /ReadNewestAction
5. As User A, navigate to User B's chat report

Expected Result:

Only a single instance of the /ReadNewestAction API call is initiated for the chat report

Actual Result:

Duplicate instances of the /ReadNewestAction API call are initiated for the chat report

Workaround:

Unknown

Platforms:

• Android: App
• Android: mWeb Chrome
• iOS: App
• iOS: mWeb Safari
• iOS: mWeb Chrome
• Windows: Chrome
• MacOS: Chrome / Safari
• MacOS: Desktop

Screenshots/Videos

Bug6976526_1760614732363.2025-10-16_14_30_58.mp4

Upwork Automation - Do Not Edit

• Upwork Job URL: https://www.upwork.com/jobs/~021990497809920039578
• Upwork Job ID: 1990497809920039578
• Last Price Increase: 2025-11-17

Issue Owner

Current Issue Owner: @

[melvin-bot]

Triggered auto assignment to @garrettmknight (Bug), see https://stackoverflow.com/c/expensify/questions/14418 for more details. Please add this bug to a GH project, as outlined in the SO.

[dmkt9]

Proposal

Please re-state the problem that we are trying to solve in this issue.

Duplicate instances of the /ReadNewestAction API call are initiated for the chat report

What is the root cause of that problem?

readNewestAction is called sequentially in two useEffect blocks here:

App/src/pages/home/report/ReportActionsList.tsx

Lines 392 to 412 in 27845f8

	useEffect(() => {
	if (report.reportID !== prevReportID) {
	return;
	}
	if (isUnread(report, transactionThreadReport, isReportArchived) || (lastAction && isCurrentActionUnread(report, lastAction, sortedVisibleReportActions))) {
	// On desktop, when the notification center is displayed, isVisible will return false.
	// Currently, there's no programmatic way to dismiss the notification center panel.
	// To handle this, we use the 'referrer' parameter to check if the current navigation is triggered from a notification.
	const isFromNotification = route?.params?.referrer === CONST.REFERRER.NOTIFICATION;
	if ((isVisible || isFromNotification) && scrollingVerticalOffset.current < CONST.REPORT.ACTIONS.ACTION_VISIBLE_THRESHOLD) {
	readNewestAction(report.reportID);
	if (isFromNotification) {
	Navigation.setParams({referrer: undefined});
	}
	} else {
	readActionSkipped.current = true;
	}
	}
	// eslint-disable-next-line react-compiler/react-compiler, react-hooks/exhaustive-deps
	}, [report.lastVisibleActionCreated, transactionThreadReport?.lastVisibleActionCreated, report.reportID, isVisible]);

App/src/pages/home/report/ReportActionsList.tsx

Lines 610 to 648 in 27845f8

	useEffect(() => {
	if (report.reportID !== prevReportID) {
	return;
	}
	if (!isVisible || !isFocused) {
	if (!lastMessageTime.current) {
	lastMessageTime.current = lastAction?.created ?? '';
	}
	return;
	}
	// In case the user read new messages (after being inactive) with other device we should
	// show marker based on report.lastReadTime
	const newMessageTimeReference = lastMessageTime.current && report.lastReadTime && lastMessageTime.current > report.lastReadTime ? userActiveSince.current : report.lastReadTime;
	lastMessageTime.current = null;
	const isArchivedReport = isArchivedNonExpenseReport(report, isReportArchived);
	const hasNewMessagesInView = scrollingVerticalOffset.current < CONST.REPORT.ACTIONS.ACTION_VISIBLE_THRESHOLD;
	const hasUnreadReportAction = sortedVisibleReportActions.some(
	(reportAction) =>
	newMessageTimeReference &&
	newMessageTimeReference < reportAction.created &&
	(isReportPreviewAction(reportAction) ? reportAction.childLastActorAccountID : reportAction.actorAccountID) !== getCurrentUserAccountID(),
	);
	if (!isArchivedReport && (!hasNewMessagesInView || !hasUnreadReportAction)) {
	return;
	}
	readNewestAction(report.reportID);
	userActiveSince.current = DateUtils.getDBTime();
	// This effect logic to `mark as read` will only run when the report focused has new messages and the App visibility
	// is changed to visible(meaning user switched to app/web, while user was previously using different tab or application).
	// We will mark the report as read in the above case which marks the LHN report item as read while showing the new message
	// marker for the chat messages received while the user wasn't focused on the report or on another browser tab for web.
	// eslint-disable-next-line react-compiler/react-compiler, react-hooks/exhaustive-deps
	}, [isFocused, isVisible]);

Each useEffect serves a different purpose. One calls readNewestAction whenever there are unread messages, while the other triggers it when the ReportScreen is re-focused or when the app returns from the background to the foreground.

App/src/pages/home/report/ReportActionsList.tsx

Lines 643 to 646 in 27845f8

	// This effect logic to `mark as read` will only run when the report focused has new messages and the App visibility
	// is changed to visible(meaning user switched to app/web, while user was previously using different tab or application).
	// We will mark the report as read in the above case which marks the LHN report item as read while showing the new message
	// marker for the chat messages received while the user wasn't focused on the report or on another browser tab for web.

What changes do you think we should make in order to solve the problem?

There are two solutions:

Solution 1:
We can merge the two useEffect blocks by adding preIsVisible and preIsFocused to ensure the second effect’s behavior is preserved.

Solution 2:
We can create a ref to store the state that determines whether readNewestAction should be called in the second useEffect.
If readNewestAction has already been triggered in the first useEffect, the state will be set to false.
Then, it can be reset to true in the second useEffect.

Or more simply, we could use useDebounce for readNewestAction with a reasonable delay.

[melvin-bot]

Job added to Upwork: https://www.upwork.com/jobs/~021978915596703523565

[melvin-bot]

Triggered auto assignment to Contributor-plus team member for initial proposal review - @dukenv0307 (External)

[dukenv0307]

@dmkt9 I don't think your RCA is correct, that's fine to trigger readNewestAction many times, but in readNewestAction because we already used writeWithNoDuplicatesConflictAction which prevents the duplication. Can you please check again?

[dmkt9]

@dukenv0307 Yes. I just double-checked. We indeed used writeWithNoDuplicatesConflictAction, but because readNewestAction is inside callbacks of two different useEffects, and those callbacks are triggered separately and asynchronously, usually after the first callback, the whole request queue gets resolved successfully, so when the second callback gets triggered, the queue is already empty.

[ShridharGoel]

Proposal

Please re-state the problem that we are trying to solve in this issue.

Opening a chat report that just received a new message fires the /ReadNewestAction API twice, which shows up as duplicate network calls and adds unnecessary traffic.

What is the root cause of that problem?

When the report gains focus, the visibility effect in ReportActionsList calls readNewestAction even if the earlier logic already handled the unread state. There is no guard that checks whether the read was previously skipped, so the second effect retriggers the write request every time the report becomes visible.

App/src/pages/home/report/ReportActionsList.tsx

Lines 610 to 641 in 7165a14

	useEffect(() => {
	if (report.reportID !== prevReportID) {
	return;
	}
	if (!isVisible || !isFocused) {
	if (!lastMessageTime.current) {
	lastMessageTime.current = lastAction?.created ?? '';
	}
	return;
	}
	// In case the user read new messages (after being inactive) with other device we should
	// show marker based on report.lastReadTime
	const newMessageTimeReference = lastMessageTime.current && report.lastReadTime && lastMessageTime.current > report.lastReadTime ? userActiveSince.current : report.lastReadTime;
	lastMessageTime.current = null;
	const isArchivedReport = isArchivedNonExpenseReport(report, isReportArchived);
	const hasNewMessagesInView = scrollingVerticalOffset.current < CONST.REPORT.ACTIONS.ACTION_VISIBLE_THRESHOLD;
	const hasUnreadReportAction = sortedVisibleReportActions.some(
	(reportAction) =>
	newMessageTimeReference &&
	newMessageTimeReference < reportAction.created &&
	(isReportPreviewAction(reportAction) ? reportAction.childLastActorAccountID : reportAction.actorAccountID) !== getCurrentUserAccountID(),
	);
	if (!isArchivedReport && (!hasNewMessagesInView || !hasUnreadReportAction)) {
	return;
	}
	readNewestAction(report.reportID);
	userActiveSince.current = DateUtils.getDBTime();

What changes do you think we should make in order to solve the problem?

Add a guard that only lets the visibility effect call readNewestAction when readActionSkipped is true, and reset the flag after the call so the API runs once per unread batch.

useEffect(() => {
    // .... existing code

    // Existing
    if (!isVisible || !isFocused) {
        if (!lastMessageTime.current) {
            lastMessageTime.current = lastAction?.created ?? '';
        }
        return;
    }

    // New
    if (!readActionSkipped.current) {
        return;
    }

    // .... existing code

    readNewestAction(report.reportID);
    readActionSkipped.current = false; // New
    userActiveSince.current = DateUtils.getDBTime();
}, [isFocused, isVisible]);