[MelvinBot]

Explanation of Change

Stops the iOS HybridApp crash LayoutManager is not initialized, window size is unavailable, thrown from FlashList's onScroll (Sentry APP-MHA).

Why it happens: Our FlashList patch 002 (skip layout when hidden) returns early when a list first measures at 0×0, so FlashList never creates its layoutManager. Upstream always creates it on the first layout. If a native scroll event arrives before the first real layout (for example, iOS adjusting the content inset with no user touch), FlashList's onScroll calls recordInteraction() → updateViewableItems(). That reads getWindowSize() before it checks whether the list has any viewability listeners, so even lists with no viewability callbacks (like Workspaces_List) throw.

What this changes: Patch 002 now also guards the scroll/viewability path it leaves without a layout manager:

1. ViewabilityManager.updateViewableItems returns early when there are no viewability listeners or !rvManager.hasLayout(), before calling getWindowSize().
2. RecyclerViewManager.recordInteraction returns early when !hasLayout(). hasInteracted stays unset until the list can measure anything, so viewabilityConfig.waitForInteraction still works on the next scroll.
3. RecyclerViewManager.computeItemViewability returns early when !hasLayout(). This covers lists with onViewableItemsChanged, which would otherwise throw from computeVisibleIndices() on the same event.

Lists that already have a layout behave exactly as before. The patch 002 entry in patches/@shopify/flash-list/details.md is updated.

Unit tests: tests/unit/FlashListTest.tsx adds two tests on RecyclerViewManager with no layout. Both fail on the unpatched code with the Sentry error, and pass with this change. The second test also checks that viewable items are still reported after the first layout, and that the early scroll does not count as the interaction for waitForInteraction.

AI tests run locally:

• npm test -- tests/unit/FlashListTest.tsx: pass (3/3). The 2 new tests fail without the fix.
• FlashList-dependent suites (TableTest, TableSelectionTest, BaseSelectionListTest, BaseSelectionListSectionsTest, SearchAutocompleteListTest, EmojiPickerMenuComponentTest, tests/unit/components/SelectionList): pass (12 suites, 188 tests).
• All 16 @shopify/flash-list patches apply in order on a clean @shopify/flash-list@2.3.2 with patch-package's apply logic, and the result matches the patched node_modules.
• npm run lint-changed, npm run typecheck, npm run spell-changed, npm run fmt (no changes), ./scripts/validatePatches.sh: pass.
• Not run locally: the full npm test suite and the Storybook smoke test. The crash is native iOS only and was not reproduced on a device.

Fixed Issues

$ #104502
PROPOSAL: #104502 (comment)

Tests

// TODO: The human co-author must fill out the tests you ran before marking this PR as "ready for review"
// Please describe what tests you performed that validates your changed worked.

• Verify that no errors appear in the JS console

Offline tests

QA Steps

// TODO: The human co-author must fill out the QA tests you ran before marking this PR as "ready for review".
// Please describe what QA needs to do to validate your changes and what areas do they need to test for regressions.

• Verify that no errors appear in the JS console

PR Author Checklist

• I linked the correct issue in the ### Fixed Issues section above
• I wrote clear testing steps that cover the changes made in this PR
  • I added steps for local testing in the Tests section
  • I added steps for the expected offline behavior in the Offline steps section
  • I added steps for Staging and/or Production testing in the QA steps section
  • I added steps to cover 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 tested this PR with a High Traffic account against the staging or production API to ensure there are no regressions (e.g. long loading states that impact usability).
• I included screenshots or videos for tests on all platforms
• I ran the tests on all platforms & verified they passed on:
  • Android: Native
  • Android: mWeb Chrome
  • iOS: Native
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
• I verified there are no console errors (if there's a console error not related to the PR, report it or open an issue for it to be fixed)
• I verified any copy / text that was added to the app 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)
• If a new code pattern is added I verified it was agreed to be used by multiple Expensify engineers
• I tested other components that can be impacted by my changes (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar are working as expected)
• If new assets were added or existing ones were modified, I verified that:
  • The assets are optimized and compressed (for SVG files, run npm run compress-svg)
  • The assets load correctly across all supported platforms.
• 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)
• If the PR modifies a component related to any of the existing Storybook stories, I tested and verified all stories for that component are still working as expected.
• If the PR modifies a component or page that can be accessed by a direct deeplink, I verified that the code functions as expected when the deeplink is used - from a logged in and logged out account.
• If the PR modifies the UI (e.g. new buttons, new UI components, changing the padding/spacing/sizing, moving components, etc) or modifies the form input styles:
  • I verified that all the inputs inside a form are aligned with each other.
  • I added Design label and/or tagged @Expensify/design so the design team can review the changes.
• If the PR adds or modifies the UI:
  • I asked an AI agent to review the changes for accessibility issues and addressed its findings.
  • I tested with a screen reader (VoiceOver on macOS) and verified all new/changed elements are reachable with a logical focus order.
  • I verified all new/changed elements have meaningful accessible names and roles.
  • I verified state changes are announced (e.g. checked/unchecked, expanded/collapsed, selected).
• I added unit tests for any new feature or bug fix in this PR to help automatically prevent regressions in this user flow.
• If the main branch was merged into this PR after a review, I tested again and verified the outcome was still expected according to the Test steps.

Screenshots/Videos

Android: Native

Android: mWeb Chrome

iOS: Native

iOS: mWeb Safari

MacOS: Chrome / Safari

[MelvinBot]

I created this PR from an upstream branch because linhvovan29546 doesn't have a fork of Expensify/App I can push to.

To take ownership of this branch and push updates, run:

git remote add upstream https://github.com/Expensify/App.git
git fetch upstream claude-flashListScrollBeforeLayout
git checkout -b claude-flashListScrollBeforeLayout upstream/claude-flashListScrollBeforeLayout
git push -u origin claude-flashListScrollBeforeLayout

Then you can close this PR and open a new one from your fork.