[$250] Distance Rate - Individual Distance rate in NewDot does not match the one in OldDot

[vincdargento]

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Version Number: 9.0.96-0
Reproducible in staging?: Yes
Reproducible in production?: Yes
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): N/A
Issue reported by: Applause Internal Team
Device used: Windows 10/ Chrome, Samsung Galaxy A12/Android 13
App Component: Money Requests

Action Performed:

Precondition: Log in to an account created with Track and Budget Expenses to have access to a Self DM

1. Navigate to OldDot (staging.expensify.com)
2. Go to Settings > Workspace > Individual > Expenses
3. In the Distance section, change the unit and the value into a different one
4. Navigate to NewDot (staging.new.expensify.com)
5. Go to a Self DM
6. Click the + icon > Create Expense
7. Enter locations and click Next
8. Scroll down a little to the Rate field

Expected Result:

Rate field shows the same value as the rate set in OldDot

Actual Result:

Rate field does not show the same value as the rate set in OldDot

Workaround:

Unknown

Platforms:

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

Screenshots/Videos

bug.mp4

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• Upwork Job URL: https://www.upwork.com/jobs/~021889675019214615866
• Upwork Job ID: 1889675019214615866
• Last Price Increase: 2025-02-26

Issue Owner

Current Issue Owner: @eh2077

[melvin-bot]

Triggered auto assignment to @slafortune (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.

[melvin-bot]

Job added to Upwork: https://www.upwork.com/jobs/~021889675019214615866

[melvin-bot]

Triggered auto assignment to Contributor-plus team member for initial proposal review - @eh2077 (External)

[FitseTLT]

@eh2077 Currently we use the default/CURRENCY_TO_DEFAULT_MILEAGE_RATE mileage rate for the currency (in this case the personal policy currency) when there is no policy linked to the report

App/src/libs/DistanceRequestUtils.ts

Lines 253 to 262 in f5cbaf2

	const currencyWithExistingRate = CONST.CURRENCY_TO_DEFAULT_MILEAGE_RATE[currency] ? currency : CONST.CURRENCY.USD;
	const mileageRate = CONST.CURRENCY_TO_DEFAULT_MILEAGE_RATE[currencyWithExistingRate];
	ensureRateDefined(mileageRate.rate);
	// Ensure the rate is updated when the currency changes, otherwise use the stored rate
	const rate = getCurrency(transaction) === currency ? transaction?.comment?.customUnit?.defaultP2PRate ?? mileageRate.rate : mileageRate.rate;
	return {
	...mileageRate,
	currency: currencyWithExistingRate,
	rate,

But in the OP what they are changing in OD is the personal policy rate so if we need to apply personal policy rate instead of the static CURRENCY_TO_DEFAULT_MILEAGE_RATE I will propose a solution but I think we need to make sure the change is intended internally 👍

[eh2077]

@FitseTLT Thanks for looking into this.

But in the OP what they are changing in OD is the personal policy rate so if we need to apply personal policy rate instead of the static CURRENCY_TO_DEFAULT_MILEAGE_RATE I will propose a solution but I think we need to make sure the change is intended internally 👍

The bug report is clear to me.

1. Navigate to OldDot (staging.expensify.com)
2. Go to Settings > Workspace > Individual > Expenses
3. In the Distance section, change the unit and the value into a different one
4. Navigate to NewDot (staging.new.expensify.com)
5. Go to a Self DM
6. Click the + icon > Create Expense
7. Enter locations and click Next
8. Scroll down a little to the Rate field

I think Workspace > Individual of OD is equal to the Self DM of ND, so individual distance rate change from OD should be reflected in ND.

@slafortune Am I right?

[OmarKoueifi]

Proposal

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

The distance rate in the new version of Expensify (NewDot) does not match the one in the old version (OldDot). This issue specifically affects individual expenses, where the incorrect mileage rate is applied, leading to inaccurate reimbursements.

What is the root cause of that problem?

• In DistanceRequestUtils.ts → getRate function, the policy being passed to getDefaultMileageRate is undefined.
  https://github.com/Expensify/App/blob/main/src/libs/DistanceRequestUtils.ts#L353-L380
• When policy is undefined, mileageRate falls back to calling getRateForP2P, which does not return the expected value.
• This results in an incorrect mileage rate being applied in individual expense calculations.

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

1. Pass the correct policy when calling getDefaultMileageRate:

• If policy is undefined, use the personal policy by calling getPersonalPolicy().
• Update the function call like this:

const defaultMileageRate = getDefaultMileageRate(policy ?? getPersonalPolicy());

2. Ensure mileageRate applies the correct logic:

• Modify the mileageRate assignment to handle cases where policy is undefined.
• Update the existing condition to ensure that when policy is undefined, we correctly fall back to customMileageRate.

const mileageRate = !!policy && isCustomUnitRateIDForP2P(transaction) 
    ? getRateForP2P(policyCurrency, transaction) 
    : customMileageRate;

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

• Test cases where policy is undefined to ensure getPersonalPolicy() is used as expected.
• Verify that mileageRate applies the correct logic when handling individual expenses.
• Ensure that default mileage rates match between OldDot and NewDot.
• Regression tests to confirm that mileage calculations remain accurate across different policy settings and workspaces.

What alternative solutions did you explore? (Optional)

Keeping the current logic but modifying getRateForP2P to handle missing policies. This was ruled out as it introduces unnecessary complexity and does not align with how default mileage rates should be determined.