Prevent LHN from remounting after navigating away from Inbox by TMisiukiewicz · Pull Request #83887 · Expensify/App

TMisiukiewicz · 2026-03-02T14:06:14Z

Explanation of Change

When navigating away from the Inbox screen to another full-screen navigator (e.g. a report), the useCustomRootStackNavigatorState hook was only keeping the last full-screen route and the one immediately before it if it was an RHP. This caused ReportsSplitNavigator — which hosts the LHN — to get unmounted and remounted on every navigation away from Inbox.

The fix simplifies the slicing logic to always keep the last two routes in the stack (i.e. lastSplitIndex - 1), ensuring the previous full-screen navigator (like ReportsSplitNavigator containing the LHN with its potentially thousands of items) stays mounted.

Additionally, usePreloadFullScreenNavigators now skips preloading a tab's navigator if its full-screen route is already present in the regular navigation stack, avoiding duplicate mounting.

Fixed Issues

$ #80560
$ #83950
$ #77174
$ #77175
PROPOSAL:

Tests

Web only

Open the app
Navigate through bottom tabs a couple of times
Verify navigating is smooth

Verify that no errors appear in the JS console

Offline tests

N/A

QA Steps

Same as tests

Verify that no errors appear in the JS console

PR Author Checklist

Screenshots/Videos

Android: Native

Android: mWeb Chrome

iOS: Native

iOS: mWeb Safari

MacOS: Chrome / Safari

Screen.Recording.2026-03-03.at.08.30.33.mov

…ng-lhn

codecov · 2026-03-02T14:28:30Z

Codecov Report

❌ Looks like you've decreased code coverage for some files. Please write tests to increase, or at least maintain, the existing level of code coverage. See our documentation here for how to interpret this table.

Files with missing lines	Coverage Δ
...avigator/useCustomRootStackNavigatorState/index.ts	`0.00% <0.00%> (ø)`
...ion/AppNavigator/usePreloadFullScreenNavigators.ts	`14.28% <0.00%> (-0.64%)`	⬇️
... and 11 files with indirect coverage changes

src/libs/Navigation/AppNavigator/usePreloadFullScreenNavigators.ts

…ng-lhn

melvin-bot · 2026-03-03T07:35:22Z

@hungvu193 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 · 2026-03-03T07:43:43Z

src/libs/Navigation/AppNavigator/usePreloadFullScreenNavigators.ts

+                    const isRouteInStack = currentRoutes.some((r) => TAB_TO_FULLSCREEN[tabName].includes(r.name as FullScreenName));
+
+                    if (isRouteInStack) {
+                        continue;


Limit stack-based skip to mounted navigators

This new isRouteInStack gate treats any route present in navigation.getState().routes as already mounted, but on Android I checked src/libs/Navigation/AppNavigator/createRootStackNavigator/useCustomRootStackNavigatorState/index.android.ts and previous full-screen routes are still sliced out when the previous route is also full-screen. In flows like Inbox → Workspaces, Inbox stays in the route state but is unmounted, so this condition skips preloadTab and forces Inbox to cold-mount again when switching back, reintroducing the tab-switch performance regression for Android users.

Useful? React with 👍 / 👎.

The cold-mount behavior on Android is tied to useCustomRootStackNavigatorState slicing and is not introduced or worsened by this change

adhorodyski · 2026-03-03T09:45:12Z

src/libs/Navigation/AppNavigator/usePreloadFullScreenNavigators.ts

@@ -134,6 +134,7 @@ function usePreloadFullScreenNavigators() {
            }
            hasPreloadedRef.current = true;
            setTimeout(() => {


I know this is not related, but why is this timer not getting cleared on unmount?

…ng-lhn

This reverts commit a09a9fe.

This reverts commit 7664d46.

hungvu193 · 2026-03-03T14:46:31Z

Reviewer Checklist

I have verified the author checklist is complete (all boxes are checked off).
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- 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
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I verified tests pass on all platforms & I tested again on:
- Android: HybridApp
- Android: mWeb Chrome
- iOS: HybridApp
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- MacOS: Chrome / Safari
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- 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.
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If any new file was added I verified that:
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Screenshots/Videos

Android: HybridApp

Android: mWeb Chrome

iOS: HybridApp

iOS: mWeb Safari

MacOS: Chrome / Safari

Screen.Recording.2026-03-03.at.21.35.02.mov

Screen.Recording.2026-03-03.at.21.36.08.mov

JS00001

OSBotify · 2026-03-03T14:59:18Z

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

github-actions · 2026-03-03T15:00:21Z

🚧 @JS00001 has triggered a test Expensify/App build. You can view the workflow run here.

github-actions · 2026-03-03T15:04:51Z

🧪🧪 Use the links below to test this adhoc build on Android, iOS, and Web. Happy testing! 🧪🧪
Built from App PR #83887.

Android 🤖	iOS 🍎
https://ad-hoc-expensify-cash.s3.us-east-1.amazonaws.com/rock-artifacts/ad-hoc/rock-android-Adhoc-c90ee41-cd00326-531110118a42f3e9cebac0cc4a2096b292a43078/index.html	https://ad-hoc-expensify-cash.s3.us-east-1.amazonaws.com/rock-artifacts/ad-hoc/rock-ios-device-AdHoc-c90ee41-cd00326-4b9f42bb81f7ef29e3f1f12df41380b152fd6bc9/index.html

Web 🕸️
https://83887.pr-testing.expensify.com

👀 View the workflow run that generated this build 👀

luacmartins

Nice! This is a great improvement

OSBotify · 2026-03-04T18:37:06Z

🚀 Deployed to staging by https://github.com/JS00001 in version: 9.3.31-0 🚀

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

…rf/prevent-remounting-lhn" This reverts commit c90ee41, reversing changes made to 2e32c72.

OSBotify · 2026-03-06T03:49:47Z

🚀 Deployed to production by https://github.com/blimpich in version: 9.3.31-12 🚀

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

OSBotify · 2026-03-06T04:15:30Z

🚀 Deployed to staging by https://github.com/JS00001 in version: 9.3.32-0 🚀

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

OSBotify · 2026-03-06T22:44:43Z

🚀 Deployed to production by https://github.com/blimpich in version: 9.3.32-3 🚀

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

TMisiukiewicz added 2 commits March 2, 2026 14:58

prevent remounting LHN after navigating away from Inbox

c6f1325

Merge remote-tracking branch 'origin/main' into perf/prevent-remounti…

e71bcad

…ng-lhn

melvin-bot bot assigned TMisiukiewicz Mar 2, 2026

TMisiukiewicz changed the title ~~[No QA] Prevent LHN from remounting after navigating away from Inbox~~ Prevent LHN from remounting after navigating away from Inbox Mar 2, 2026

BartekObudzinski reviewed Mar 2, 2026

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src/libs/Navigation/AppNavigator/usePreloadFullScreenNavigators.ts Outdated Show resolved Hide resolved

JS00001 self-requested a review March 2, 2026 17:34

mountiny mentioned this pull request Mar 2, 2026

[Due for payment 2026-03-13] [Performance] Hide useCustomRootStackNavigatorState instead of removing it from the render tree #83950

Closed

TMisiukiewicz added 2 commits March 3, 2026 08:04

move navigation.getState().routes outside the loop

f8a01ee

Merge remote-tracking branch 'origin/main' into perf/prevent-remounti…

eb9c4e5

…ng-lhn

TMisiukiewicz marked this pull request as ready for review March 3, 2026 07:35

TMisiukiewicz requested review from a team as code owners March 3, 2026 07:35

melvin-bot bot requested review from hungvu193 and removed request for a team March 3, 2026 07:35

melvin-bot bot requested review from trjExpensify and removed request for a team March 3, 2026 07:35

chatgpt-codex-connector bot reviewed Mar 3, 2026

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adhorodyski reviewed Mar 3, 2026

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adhorodyski approved these changes Mar 3, 2026

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TMisiukiewicz added 6 commits March 3, 2026 11:50

keep preserved screens active on web

7664d46

Prevent pop-back to bottom of navigation stack

a09a9fe

Merge remote-tracking branch 'origin/main' into perf/prevent-remounti…

0815a80

…ng-lhn

Merge remote-tracking branch 'origin/main' into perf/prevent-remounti…

5e809e4

…ng-lhn

Revert "Prevent pop-back to bottom of navigation stack"

4512c8a

This reverts commit a09a9fe.

Revert "keep preserved screens active on web"

a699d01

This reverts commit 7664d46.

TMisiukiewicz mentioned this pull request Mar 3, 2026

[Tracking] Large customer account performance and UX support #80560

Open

JS00001 approved these changes Mar 3, 2026

View reviewed changes

hungvu193 approved these changes Mar 3, 2026

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melvin-bot bot requested a review from JS00001 March 3, 2026 14:48

JS00001 approved these changes Mar 3, 2026

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JS00001 merged commit c90ee41 into Expensify:main Mar 3, 2026
33 checks passed

luacmartins reviewed Mar 3, 2026

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WojtekBoman mentioned this pull request Mar 4, 2026

Remove Inbox from preloaded navigators to prevent CPU spike on web #84025

Merged

52 tasks

OSBotify mentioned this pull request Mar 4, 2026

Deploy Checklist: New Expensify 2026-03-04 #84164

Closed

TMisiukiewicz added a commit to callstack-internal/Expensify-App that referenced this pull request Mar 5, 2026

Revert "Merge pull request Expensify#83887 from callstack-internal/pe…

6ea500b

…rf/prevent-remounting-lhn" This reverts commit c90ee41, reversing changes made to 2e32c72.

TMisiukiewicz mentioned this pull request Mar 5, 2026

[CP Staging][No QA] Revert "Prevent LHN from remounting after navigating away from Inbox" #84249

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52 tasks

mkhutornyi mentioned this pull request Mar 5, 2026

Revert "Prevent LHN from remounting after navigating away from Inbox" #84287

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MelvinBot mentioned this pull request Mar 5, 2026

Accounting - Central pane shows Workspaces page when Accounting page is loading #84225

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7 tasks

This was referenced Mar 6, 2026

[Due for payment 2026-03-13] [Due for payment 2026-03-11] [Tracking][Metrics] Improve ManualNavigateToReports #77174

Open

[Metrics] Improve ManualNavigateToInboxTab #77175

Open

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TMisiukiewicz commented Mar 2, 2026 • edited by JS00001 Loading Uh oh! There was an error while loading. Please reload this page.

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