Fix commuter distance flicker after rate changes by fedirjh · Pull Request #98371 · Expensify/App

fedirjh · 2026-08-11T21:25:44Z

Explanation of Change

When a workspace distance unit changed, the optimistic rate update converted the transaction's already rounded quantity into the new unit. For example, an exact 10 km route stored as 6.21 miles became 9.99 km optimistically, then changed to 10 km when the server response arrived. This caused the Original and Removed commuter distances to flicker between different values.

This change derives the converted quantity from the transaction's exact routeDistanceMeters value when available. Older transactions without that field retain the existing quantity-conversion fallback. The commuter exclusion, amount, and merchant are therefore calculated from the same exact route distance as the server.

Fixed Issues

$ #98231
PROPOSAL:

Tests

Enable distance rates in a workspace and create a second distance rate.
Enable "Exclude a fixed distance per claim" in the workspace distance settings.
Create a map distance expense.
Change the workspace distance unit.
Open the expense and select another distance rate.
Verify the Original and Removed commuter distances immediately show the correct converted values without flickering.
Verify the final values remain unchanged after the server response arrives.

Automated validation:

bun run test -- --runInBand --watchman=false tests/unit/TransactionUtilsTest.ts
bun x eslint src/libs/TransactionUtils/index.ts tests/unit/TransactionUtilsTest.ts
bun run typecheck-tsgo reports only the two existing unrelated baseline errors.
Verify that no errors appear in the JS console

Offline tests

Complete steps 1–4 above, then go offline.
Open the expense and select another distance rate.
Verify the Original and Removed commuter distances immediately show the correct converted values without flickering.
Reconnect and verify the values remain unchanged after synchronization.

QA Steps

Same as Tests.

Verify that no errors appear in the JS console

PR Author Checklist

Screenshots/Videos

CleanShot.2026-08-11.at.22.29.32.mp4

Android: Native

Not tested yet.

Android: mWeb Chrome

Not tested yet.

iOS: Native

Not tested yet.

iOS: mWeb Safari

Not tested yet.

MacOS: Chrome / Safari

Not tested yet.

melvin-bot · 2026-08-11T21:31:52Z

@marufsharifi Please copy/paste the Reviewer Checklist from here into a new comment on this PR and complete it. If you have the K2 extension, you can simply click: [this button]

melvin-bot · 2026-08-11T21:31:58Z

@Gonals Please copy/paste the Reviewer Checklist from here into a new comment on this PR and complete it. If you have the K2 extension, you can simply click: [this button]

codecov · 2026-08-11T21:33:12Z

Codecov Report

✅ Changes either increased or maintained existing code coverage, great job!

Files with missing lines	Coverage Δ
src/libs/TransactionUtils/index.ts	`91.85% <100.00%> (+0.70%)`	⬆️
... and 10 files with indirect coverage changes

marufsharifi · 2026-08-11T21:37:24Z

Reviewer Checklist

I have verified the author checklist is complete (all boxes are checked off).
I verified the correct issue is linked in the ### Fixed Issues section above
I verified testing steps are clear and they cover the changes made in this PR
- I verified the steps for local testing are in the Tests section
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- I verified the steps cover any possible failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
- I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
I checked that screenshots or videos are included for tests on all platforms
I included screenshots or videos for tests on all platforms
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I verified tests pass on all platforms & I tested again on:
- Android: HybridApp
- Android: mWeb Chrome
- iOS: HybridApp
- iOS: mWeb Safari
- MacOS: Chrome / Safari
If there are any errors in the console that are unrelated to this PR, I either fixed them (preferred) or linked to where I reported them in Slack
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Screenshots/Videos

Android: HybridApp

Android: mWeb Chrome

iOS: HybridApp

iOS: mWeb Safari

MacOS: Chrome / Safari

Screen.Recording.2026-08-12.at.2.35.13.AM.mov

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marufsharifi · 2026-08-11T22:26:53Z

@fedirjh, could you please check the failed actions. thanks.

fedirjh · 2026-08-11T22:49:06Z

@marufsharifi This is ready.

marufsharifi · 2026-08-11T22:51:03Z

@MelvinBot Review

Co-authored-by: Maruf Sharifi <maruf.sharifi.work@gmail.com>

MelvinBot · 2026-08-11T22:59:23Z

Review

The logic change is sound — deriving the converted quantity from the exact routeDistanceMeters (with a rounding-tolerance guard for manual overrides) correctly eliminates the double-rounding flicker. But there's one blocking bug that's currently failing CI.

🔴 Dangling duplicate expression breaks `typecheck` (and `ESLint`/`Oxfmt`)

src/libs/TransactionUtils/index.ts:762-763

            Math.abs(quantity - DistanceRequestUtils.convertDistanceUnit(routeDistanceMeters, existingDistanceUnit)) > ROUNDING_TOLERANCE;
            Math.abs(quantity - DistanceRequestUtils.convertDistanceUnit(routeDistanceMeters, existingDistanceUnit)) > 0.01;   // ← leftover

The last commit (Apply suggestions from code review) extracted 0.01 into the ROUNDING_TOLERANCE constant but left the original line behind. Line 763 is now a standalone no-op expression statement (its result is discarded), and it lives outside the typeof narrowing that guards line 762 — so quantity/routeDistanceMeters are number | undefined there.

That single line is the cause of all three failing checks:

typecheck ❌ — TS18049: 'quantity' is possibly 'null' or 'undefined' and TS2345 at index.ts(763,...)
ESLint (pending) — will fail @typescript-eslint/no-unused-expressions
Oxfmt ❌ — diff on this file

Fix: delete line 763, then run npm run fmt:

        const hasManualDistanceOverride =
            typeof routeDistanceMeters === 'number' &&
            typeof quantity === 'number' &&
            !!existingDistanceUnit &&
            Math.abs(quantity - DistanceRequestUtils.convertDistanceUnit(routeDistanceMeters, existingDistanceUnit)) > ROUNDING_TOLERANCE;

Everything else looks good — Bun tests pass, the new manual-override and fallback-policy test cases are solid coverage, and the convertDistanceUnit(meters, unit) calls are used correctly.

Note on verification

I didn't run the UI flicker flow — the fix needs to compile clean first. Once line 763 is removed and CI is green, please re-verify the Original/Removed commuter distances no longer flicker per the test steps.

Next Steps: Reply with @MelvinBot implement this to have me push the one-line fix, or @MelvinBot <feedback> to refine.

marufsharifi

LGTM

fedirjh added 2 commits August 11, 2026 22:23

fix: use exact route distance on rate change

0d71025

test: cover exact commuter unit conversion

b65e71d

melvin-bot Bot assigned fedirjh Aug 11, 2026

fedirjh marked this pull request as ready for review August 11, 2026 21:31

fedirjh requested review from a team as code owners August 11, 2026 21:31

melvin-bot Bot requested review from garrettmknight and marufsharifi and removed request for a team and garrettmknight August 11, 2026 21:31

melvin-bot Bot requested review from a team and Gonals August 11, 2026 21:31

melvin-bot Bot removed the request for review from a team August 11, 2026 21:31

chatgpt-codex-connector Bot reviewed Aug 11, 2026

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Comment thread src/libs/TransactionUtils/index.ts Outdated

fedirjh added 4 commits August 11, 2026 23:13

fix: preserve manual distance on rate change

89de934

test: cover manual distance rate change

b1fc312

test: cover cross-policy rate conversion

22418b0

Merge branch 'Expensify:main' into fix/98231-commuter-rate-flicker

7634441

marufsharifi reviewed Aug 11, 2026

View reviewed changes

Comment thread src/libs/TransactionUtils/index.ts

Comment thread src/libs/TransactionUtils/index.ts Outdated

Comment thread tests/unit/TransactionUtilsTest.ts

chore: Apply suggestions from code review

7923c5a

Co-authored-by: Maruf Sharifi <maruf.sharifi.work@gmail.com>

fedirjh added 2 commits August 12, 2026 00:09

fix: reuse exact route distance guard

fcc513f

test: cover legacy distance conversion

3123fba

fedirjh requested a review from marufsharifi August 11, 2026 23:35

marufsharifi approved these changes Aug 11, 2026

View reviewed changes

Gonals approved these changes Aug 12, 2026

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Fix commuter distance flicker after rate changes - #98371

Fix commuter distance flicker after rate changes#98371
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Explanation of Change

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🔴 Dangling duplicate expression breaks typecheck (and ESLint/Oxfmt)

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🔴 Dangling duplicate expression breaks `typecheck` (and `ESLint`/`Oxfmt`)