[Due for payment 2026-07-03] Distance - Date change system message does not appear when it involves rate change

@c3024

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Version Number: 9.4.19-1
Reproducible in staging?: Yes
Reproducible in production?: N/A - new feature, doesn't exist in prod
If this was caught during regression testing, add the test name, ID and link from BrowserStack: #93755
Email or phone of affected tester (no customers): applausetester+ssndjois2jd1@applause.expensifail.com
Issue reported by: Applause Internal Team
Bug source: Exploratory - Significant User Experience Deterioration
Device used: Mac 26.5 / Chrome
App Component: Money Requests

Action Performed:

Precondition:

Log in with Expensifail account.
Enable Distance rates.
Create the following distance rates:
Rate A: $0.70/mi, valid Jan 1 2025 - Dec 31 2025
Rate B: $0.50/mi, valid Jan 1 2026 - Dec 31 2026

Go to staging.new.expensify.com.
Go to workspace chat.
Create a distance expense with date from 2025.
Open the expense.
Click Date.
Change the date to 2026.

Expected Result:

Date change system message will appear in the expense.

Actual Result:

Date change system message does not appear in the expense when it involves rate change.

Workaround:

Unknown

Platforms:

Screenshots/Videos

Bug7190190_1782333604117.9.mp4

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Applause Internal Information
Exported by: Mita Rachim
Bug ID: 7190190

Issue Owner

Current Issue Owner: @c3024

While Applause doesn't embed attachments for this bug, here are the links for quick view:
https://platform.applause.com/services/links/v1/external/1b1b109cfc6e57ddd57f8d857731ee8bae5d0ead8b7eaa17618c7af7341120da

You have been assigned to this deploy blocker because you recently merged this PR: #93755

💬 A slack conversation has been started in #expensify-open-source

👋 Friendly reminder that deploy blockers are time-sensitive ⏱ issues! Check out the open `StagingDeployCash` deploy checklist to see the list of PRs included in this release, then work quickly to do one of the following:

Identify the pull request that introduced this issue and revert it.
Find someone who can quickly fix the issue.
Fix the issue yourself.

Proposal

What is the root cause of that problem?

When a date edit also moves the expense into a different mileage rate window, PR #93755 routes the edit through updateMoneyRequestDistanceRate and bundles both changes into a single transactionChanges object (created + customUnitRateID) — see UpdateMoneyRequest.ts. The resulting modified-expense report action therefore carries oldCreated/created and oldAmount/amount/oldMerchant/merchant.

The system message text is built by getForReportAction in ModifiedExpenseMessage.ts. Because the merchant is in distance format (contains @), it hits the early return getForDistanceRequest(...) at ModifiedExpenseMessage.ts:293-295. That early return means execution never reaches the date fragment block at ModifiedExpenseMessage.ts:329-332, so the "changed the date" part of the message is silently dropped. Only the rate/distance change is shown.

This is why the date change message appears for a plain date edit but disappears whenever the edit also triggers a rate change.

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

In getForReportAction, when the action is a distance edit that also has a created change (oldCreated + created present), do not return early with only the distance message. Instead, build the date fragment as well and combine it with the distance/rate fragment so both changes are reflected in one system message (e.g. "changed the date to … and the rate to …").

Concretely, compute the distance-request message string and the date fragment, then merge them through the existing setFragments/changeFragments joining logic rather than returning immediately at line 294. The plain date-only and rate-only paths should remain unchanged.

What alternative solutions did you explore? (Optional)

Keep the date and rate edits as two separate report actions (revert the bundling from Recalculate mileage rate when editing distance expense date #93755) so each renders its own message — larger behavioral change and likely undesirable.
Have getForDistanceRequest itself accept and append the date change — keeps the change localized but couples date formatting into the distance helper.

Confidence & evidence

Confidence: High. The symptom ("date change message missing only when rate also changes") is fully explained by the early return at ModifiedExpenseMessage.ts:294, which structurally bypasses the date fragment builder. The bundling of created + customUnitRateID into one transaction change was introduced by the flagged PR #93755, which is why this is a new deploy blocker. The rendering path is deterministic from the action's originalMessage, so this drops the date regardless of whether the message comes from the optimistic update or the server response.

Not yet verified at runtime / in logs — analysis is from code only.

Next Steps for Contributor+ team:
To accept: @MelvinBot implement [this](https://github.com/Expensify/App/issues/94520) to create a draft PR.
To refine: @MelvinBot <your feedback>
To reject: Explain why you are rejecting Melvin's proposal.

I don't think this needs to be a blocker because the feature is still under a beta.

@c3024

@c3024 Uh oh! This issue is overdue by 2 days. Don't forget to update your issues!

BugZero Checklist:

[Contributor] The offending PR and associated issue have been commented on, pointing out the bug it caused and why, so the author and reviewers can learn from the mistake.

Link to the comment on the PR: Recalculate mileage rate when editing distance expense date #93755 (comment)
Link to the comment on the Issue: [Due for payment 2026-07-02] [DB MileageRate] App: Support date-aware mileage rate recalculation when editing distance request date #89836 (comment)
[Contributor] If the regression was CRITICAL (e.g. interrupts a core flow) A discussion in #expensify-open-source has been started about whether any other steps should be taken (e.g. updating the PR review checklist) in order to catch this type of bug sooner.

Link to discussion: N/A — not critical. This is not a regression. The distance rates feature is new. It is behind a beta and this only affects the system-message text (not a core flow), so no Slack discussion was needed.
[Contributor] If it was decided to create a regression test for the bug, please propose the regression test steps using the template below to ensure the same bug will not reach production again.
[BugZero Assignee] Create a GH issue for creating/updating the regression test once above steps have been agreed upon.

Link to issue: https://github.com/Expensify/Expensify/issues/657644

Regression Test Proposal

Precondition:

Enable Distance rates on a workspace and create two date-bound mileage rates, e.g. Rate A: $0.70/mi valid Jan 1 2025 – Dec 31 2025, and Rate B: $0.50/mi valid Jan 1 2026 – Dec 31 2026.
Create a workspace distance expense with a date in 2025 (so it uses Rate A).

Test:

Open the workspace distance expense.
Tap Date and change the date to a day in 2026 (so the applicable rate switches to Rate B), then save.
Open the expense's chat/thread.
Verify a system message appears that reports BOTH changes — the rate change and the date change (e.g. "changed the rate to ... (previously ...), which updated the amount to ... (previously ...)" followed by "changed the date to 2026-... (previously 2025-...)").
Tap Date again and change it to another day within the same 2026 window (so the rate does NOT change), then save.
Verify the system message reports the date change ("changed the date to ... (previously ...)").

Do we agree 👍 or 👎

Zapier Logs

Run ID: 00040eee-d30c-a256-768a-85e804a9ee94

@c3024

@c3024 Whoops! This issue is 2 days overdue. Let's get this updated quick!

@c3024

@c3024 Uh oh! This issue is overdue by 2 days. Don't forget to update your issues!

No payment is due here. This issue is open only to add the regression test.

@c3024

@c3024 Uh oh! This issue is overdue by 2 days. Don't forget to update your issues!

@mallenexpensify

@mallenexpensify there is no payment due here but we have a regression test to add.

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[Due for payment 2026-07-03] Distance - Date change system message does not appear when it involves rate change #94520

Action Performed:

Expected Result:

Actual Result:

Workaround:

Platforms:

Screenshots/Videos

Proposal

What is the root cause of that problem?

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

What alternative solutions did you explore? (Optional)

15 remaining items

BugZero Checklist:

Regression Test Proposal

Precondition:

Test:

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[Due for payment 2026-07-03] Distance - Date change system message does not appear when it involves rate change #94520

Description

Action Performed:

Expected Result:

Actual Result:

Workaround:

Platforms:

Screenshots/Videos

Activity

applause-bot commented on Jun 24, 2026

melvin-bot commented on Jun 24, 2026

melvin-bot commented on Jun 24, 2026

github-actions commented on Jun 24, 2026

MelvinBot commented on Jun 24, 2026

Proposal

What is the root cause of that problem?

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

What alternative solutions did you explore? (Optional)

neil-marcellini commented on Jun 24, 2026

15 remaining items

melvin-bot commented on Jun 29, 2026

c3024 commented on Jun 30, 2026

BugZero Checklist:

Regression Test Proposal

Precondition:

Test:

melvin-bot commented on Jul 3, 2026

melvin-bot commented on Jul 4, 2026

c3024 commented on Jul 4, 2026

melvin-bot commented on Jul 7, 2026

c3024 commented on Jul 8, 2026

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