[cp staging] fix(iOS): keep ScrollAnchor mounted to prevent scroll reset when MVCP toggles by sosek108 · Pull Request #88923 · Expensify/App

sosek108 · 2026-04-27T11:46:23Z

Explanation of Change

Adds FlashList patch 007 that keeps ScrollAnchor always mounted when the maintainVisibleContentPosition (MVCP) prop is defined, regardless of the disabled flag on that prop.

Root cause: When maintainVisibleContentPosition.disabled toggled from true to false (e.g. when a user scrolls up in a permalinked report), the ScrollAnchor component unmounted. On the native Fabric side, this caused _firstVisibleView's weak reference to become nil. On remount, _prevFirstVisibleFrame held a stale origin of 1,000,000 + X, so the computed deltaY = -(1,000,000 + X) produced a massive upward scroll jump, resetting the list to the top.

Fix: Keep ScrollAnchor always mounted when the MVCP prop is present. JS-level scrollBy corrections remain gated by shouldMaintainVisibleContentPosition(), so the anchor stays visually inert when MVCP is logically off — only the native view lifecycle changes.

Fixed Issues

$ #88238
$ #88955
$ #89052
PROPOSAL:

Tests

Scenario 1
Prequisities: have a chat between user A and user B

From user B send a lot of messages to user A
Send an IOU money request from B to A
Send another couple of messages
a. The idea is there is scrolling possible and money request is in between
User A: log in on iOS device
Go to chat with User B
Scroll mutliple times UP and DOWN
Verify scrolling is smooth

Scenario 2

Launch Expensify app.
Go to empty chat.
Send three images.
Tap on the composer.
Swipe all the way to the top quickly.

Scenario 3
Preconditions:
a. Set Submissions to Instantly
b. Disable Approvals and Payments
Steps:

Go to workspace chat
Create two non-reimbursable expenses
Retract each report (open report > More > Retract)
Go to Spend > Expenses
Bulk select both expenses
Click dropdown button > Duplicate expenses
Go back to workspace chat
Try to scroll the workspace chat

Offline tests

N/A

QA Steps

Same as tests

PR Author Checklist

Screenshots/Videos

Android: Native

Nagranie.z.ekranu.2026-04-27.o.14.11.05.mov

Android: mWeb Chrome

iOS: Native

ios_after.mov

iOS: mWeb Safari

MacOS: Chrome / Safari

Nagranie.z.ekranu.2026-04-27.o.14.12.28.mov

… toggles

github-actions · 2026-04-27T11:46:31Z

⚠️ This PR is possibly changing native code and/or updating libraries, it may cause problems with HybridApp. Please check if any patch updates are required in the HybridApp repo and run an AdHoc build to verify that HybridApp will not break. Ask Contributor Plus for help if you are not sure how to handle this. ⚠️

sosek108 · 2026-04-27T12:01:06Z

Before:

ios_before.mov

sosek108 · 2026-04-27T12:01:20Z

After:

ios_after.mov

melvin-bot · 2026-04-27T12:14:33Z

@ShridharGoel 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]

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chatgpt-codex-connector · 2026-04-27T12:25:29Z

+    if (maintainVisibleContentPosition != null) {
+       return {
+-        ...maintainVisibleContentPosition,
+         minIndexForVisible: 0,


Preserve MVCP options when building internal config

The new maintainVisibleContentPositionInternal object drops ...maintainVisibleContentPosition, so all caller-provided fields except minIndexForVisible are discarded. This means options like disabled and autoscrollToTopThreshold are no longer forwarded to the internal MVCP prop, which changes behavior for existing call sites that intentionally pass maintainVisibleContentPosition={{disabled: ...}} (for example in selection/search lists) and can cause unexpected scroll pinning/jumps when list data updates. The anchor-lifetime fix can be kept while still preserving non-overridden MVCP fields.

Useful? React with 👍 / 👎.

…leContentPosition

…ainVisibleContentPosition" This reverts commit ebd5a65.

…leContentPosition

ShridharGoel · 2026-04-28T12:18:52Z

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
- I verified the steps for Staging and/or Production testing are in the QA steps section
- 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
I verified that the composer does not automatically focus or open the keyboard on mobile unless explicitly intended. This includes checking that returning the app from the background does not unexpectedly open the keyboard.
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
I verified there are no new alerts related to the canBeMissing param for useOnyx
I verified proper code patterns were followed (see Reviewing the code)
- I verified that any callback methods that were added or modified are named for what the method does and never what callback they handle (i.e. toggleReport and not onIconClick).
- I verified that comments were added to code that is not self explanatory
- I verified that any new or modified comments were clear, correct English, and explained "why" the code was doing something instead of only explaining "what" the code was doing.
- I verified any copy / text shown in the product is localized by adding it to src/languages/* files and using the translation method
- I verified all numbers, amounts, dates and phone numbers shown in the product are using the localization methods
- I verified any copy / text that was added to the app is grammatically correct in English. It adheres to proper capitalization guidelines (note: only the first word of header/labels should be capitalized), and is either coming verbatim from figma or has been approved by marketing (in order to get marketing approval, ask the Bug Zero team member to add the Waiting for copy label to the issue)
- I verified proper file naming conventions were followed for any new files or renamed files. All non-platform specific files are named after what they export and are not named "index.js". All platform-specific files are named for the platform the code supports as outlined in the README.
- I verified the JSDocs style guidelines (in STYLE.md) were followed
If a new code pattern is added I verified it was agreed to be used by multiple Expensify engineers
I verified that this PR follows the guidelines as stated in the Review Guidelines
I verified other components that can be impacted by these changes have been tested, and I retested again (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar have been tested & I retested again)
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I verified any variables that can be defined as constants (ie. in CONST.ts or at the top of the file that uses the constant) are defined as such
If a new component is created I verified that:
- A similar component doesn't exist in the codebase
- All props are defined accurately and each prop has a /** comment above it */
- The file is named correctly
- The component has a clear name that is non-ambiguous and the purpose of the component can be inferred from the name alone
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If any new file was added I verified that:
- The file has a description of what it does and/or why is needed at the top of the file if the code is not self explanatory
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- A similar style doesn't already exist
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If the PR modifies code that runs when editing or sending messages, I tested and verified there is no unexpected behavior for all supported markdown - URLs, single line code, code blocks, quotes, headings, bold, strikethrough, and italic.
If the PR modifies a generic component, I tested and verified that those changes do not break usages of that component in the rest of the App (i.e. if a shared library or component like Avatar is modified, I verified that Avatar is working as expected in all cases)
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- I verified that all the inputs inside a form are aligned with each other.
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If a new page is added, I verified it's using the ScrollView component to make it scrollable when more elements are added to the page.
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Screenshots/Videos

Android: HybridApp

Android: mWeb Chrome

iOS: HybridApp

Screen.Recording.2026-04-28.at.6.12.52.PM.mov

iOS: mWeb Safari

MacOS: Chrome / Safari

…or-mounted fix(iOS): keep ScrollAnchor mounted to prevent scroll reset when MVCP toggles (cherry picked from commit c79b2d0) (cherry-picked to staging by arosiclair)

OSBotify · 2026-04-28T15:18:43Z

✋ This PR was not deployed to staging yet because QA is ongoing. It will be automatically deployed to staging after the next production release.

OSBotify · 2026-04-28T16:11:55Z

🚀 Cherry-picked to staging by https://github.com/arosiclair in version: 9.3.64-9 🚀

platform	result
🕸 web 🕸	success ✅
🤖 android 🤖	success ✅
🍎 iOS 🍎	success ✅

Bundle Size Analysis (Sentry):

Android
iOS

github-actions · 2026-04-28T16:58:01Z

🚧 @arosiclair has triggered a test Expensify/App build. You can view the workflow run here.

OSBotify · 2026-04-28T17:09:05Z

🚀 Cherry-picked to staging by https://github.com/arosiclair in version: 9.3.64-10 🚀

platform	result
🕸 web 🕸	success ✅
🤖 android 🤖	failure ❌
🍎 iOS 🍎	success ✅

Bundle Size Analysis (Sentry):

Android
iOS

github-actions · 2026-04-28T17:10:28Z

🧪🧪 Use the links below to test this adhoc build on Android, iOS, and Web. Happy testing! 🧪🧪
Built from App PR #88923.

Android 🤖	iOS 🍎
https://ad-hoc-expensify-cash.s3.us-east-1.amazonaws.com/rock-artifacts/ad-hoc/rock-android-Adhoc-c79b2d0-76d1aa4-3f9143331fbc1fa15a2789c87a82c0d56989e1dd/index.html	https://ad-hoc-expensify-cash.s3.us-east-1.amazonaws.com/rock-artifacts/ad-hoc/rock-ios-device-AdHoc-c79b2d0-76d1aa4-01dadcae62c686a0e744e0376a6d7f6386a942a2/index.html

Web 🕸️
https://88923.pr-testing.expensify.com

👀 View the workflow run that generated this build 👀

fix(iOS): keep ScrollAnchor mounted to prevent scroll reset when MVCP…

2aa4756

… toggles

melvin-bot Bot assigned sosek108 Apr 27, 2026

fix patch file format: blank context lines need leading space

159c902

sosek108 marked this pull request as ready for review April 27, 2026 12:14

sosek108 requested a review from a team as a code owner April 27, 2026 12:14

melvin-bot Bot requested review from ShridharGoel and removed request for a team April 27, 2026 12:14

chatgpt-codex-connector Bot reviewed Apr 27, 2026

View reviewed changes

mountiny self-requested a review April 27, 2026 12:40

sosek108 added 3 commits April 27, 2026 17:04

fix patch 007: preserve MVCP spread when removing shouldMaintainVisib…

ebd5a65

…leContentPosition

Revert "fix patch 007: preserve MVCP spread when removing shouldMaint…

d594936

…ainVisibleContentPosition" This reverts commit ebd5a65.

fix patch 007: preserve MVCP spread when removing shouldMaintainVisib…

1810dd5

…leContentPosition

sosek108 mentioned this pull request Apr 28, 2026

iOS - Chat - Report turns blank when swiping up #88955

Closed

7 tasks

situchan mentioned this pull request Apr 28, 2026

iOS - Chat - WS chat becomes blank when opening and scrolling after duplicate expenses #89052

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7 tasks

ShridharGoel approved these changes Apr 28, 2026

View reviewed changes

melvin-bot Bot requested a review from JS00001 April 28, 2026 12:43

JS00001 approved these changes Apr 28, 2026

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arosiclair approved these changes Apr 28, 2026

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arosiclair merged commit c79b2d0 into Expensify:main Apr 28, 2026
37 checks passed

JS00001 changed the title ~~fix(iOS): keep ScrollAnchor mounted to prevent scroll reset when MVCP toggles~~ [cp staging] fix(iOS): keep ScrollAnchor mounted to prevent scroll reset when MVCP toggles Apr 28, 2026

OSBotify added the CP Staging marks PRs that have been CP'd to staging label Apr 28, 2026

OSBotify mentioned this pull request Apr 28, 2026

Deploy Checklist: New Expensify 2026-04-23 #88633

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JS00001 mentioned this pull request Apr 29, 2026

iOS - Spend - Blank space appears above list after entering selection mode #89191

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7 tasks

situchan mentioned this pull request Apr 29, 2026

Revert "[cp staging] fix(iOS): keep ScrollAnchor mounted to prevent scroll reset when MVCP toggles" #89211

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arosiclair mentioned this pull request Apr 29, 2026

PR checklist #89226

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[cp staging] fix(iOS): keep ScrollAnchor mounted to prevent scroll reset when MVCP toggles#88923

[cp staging] fix(iOS): keep ScrollAnchor mounted to prevent scroll reset when MVCP toggles#88923
arosiclair merged 5 commits intoExpensify:mainfrom
callstack-internal:fix/keep-scrollanchor-mounted

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