Expense - Error when paying expense with negative amount

[lanitochka17]

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Version Number: 9.0.87-0
Reproducible in staging?: Y
Reproducible in production?: Y
If this was caught on HybridApp, is this reproducible on New Expensify Standalone?: N/A
If this was caught during regression testing, add the test name, ID and link from TestRail: N/A
Email or phone of affected tester (no customers): applausetester+100106kh@applause.expensifail.com
**Issue reported by:*Applause - Internal Team
Component: Money Requests

Action Performed:

Precondition:

• Workspace has per diem rates.
• At least one subrate has negative amount.

1. Go to staging.new.expensify.com
2. Go to workspace chat
3. Submit a per diem expense with negative subrate
4. Go to expense report
5. Click Pay elsewhere

Expected Result:

The expense can be paid without issue (we can pay negative amount on Old Dot)

Actual Result:

Error shows up when paying expense with negative amount

Workaround:

Unknown

Platforms:

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

• Android: Standalone
• Android: HybridApp
• Android: mWeb Chrome
• iOS: Standalone
• iOS: HybridApp
• iOS: mWeb Safari
• MacOS: Chrome / Safari
• MacOS: Desktop

Screenshots/Videos

Add any screenshot/video evidence

Bug6717074_1737143663523.20250118_035139.mp4

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[melvin-bot]

Triggered auto assignment to @muttmuure (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.

[bernhardoj]

🚨 Edited by proposal-police: This proposal was edited at 2025-01-18 04:36:58 UTC.

Proposal

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

Error when paying report with negative amount.

What is the root cause of that problem?

When we pay the expense report, the amount param passed to the API is positive instead of negative. If we look at the expense report object, the total is indeed positive. But when we pay it, we should convert it to negative.

Normally, the expense report will have a negative total and we negate it before displaying it. That's why the pay button shows a negative amount.

However, when paying the report, we use abs value. So, the total stays positive.

App/src/libs/actions/IOU.ts

Line 7652 in 64ed6a5

amount: Math.abs(total),

This was added in #36904. On one of the commit of the PR, we already negate the amount.

Then, the PR has conflict and at the end, abs is used.

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

We should negate the total when it's an expense report, like it was done here.

App/src/libs/actions/IOU.ts

Lines 7433 to 7440 in 64ed6a5

	let total = (iouReport?.total ?? 0) - (iouReport?.nonReimbursableTotal ?? 0);
	if (hasHeldExpensesReportUtils(iouReport?.reportID ?? '') && !full && !!iouReport?.unheldTotal) {
	total = iouReport.unheldTotal - (iouReport?.unheldNonReimbursableTotal ?? 0);
	}
	const optimisticIOUReportAction = buildOptimisticIOUReportAction(
	CONST.IOU.REPORT_ACTION_TYPE.PAY,
	isExpenseReport(iouReport) ? -total : total,

let total = (iouReport?.total ?? 0) - (iouReport?.nonReimbursableTotal ?? 0);
if (hasHeldExpensesReportUtils(iouReport?.reportID ?? '') && !full && !!iouReport?.unheldTotal) {
    total = iouReport.unheldTotal - (iouReport?.unheldNonReimbursableTotal ?? 0);
}
// or we can use abs for non expense report
total = isExpenseReport(iouReport) ? -total : total;

const optimisticIOUReportAction = buildOptimisticIOUReportAction(
    CONST.IOU.REPORT_ACTION_TYPE.PAY,
    total,

Then remove the abs from here.

App/src/libs/actions/IOU.ts

Line 7652 in 64ed6a5

amount: Math.abs(total),

But we still have 1 issue left, that is the paid system message still shows the amount in positive. To fix it, we need to apply the same logic here.

App/src/libs/ReportUtils.ts

Line 7796 in 64ed6a5

const formattedAmount = convertToDisplayString(Math.abs(amount), currency) ?? '';

What specific scenarios should we cover in automated tests to prevent reintroducing this issue in the future?

We can specifically test getPayMoneyRequestParams to make sure it returns the correct total depending on the report type and the current total value.

[melvin-bot]

@muttmuure Whoops! This issue is 2 days overdue. Let's get this updated quick!

[muttmuure]

I'm confused, in what circumstances would you pay an expense with a negative amount?

[muttmuure]

Asking about this here: https://expensify.slack.com/archives/C06ML6X0W9L/p1737727597109679

[muttmuure]

We think this scenario would not happen, so I'm going to close it out in favor of focusing on other issues.