decompose ReportActionsList: 4

[adhorodyski]

Explanation of Change

PR 4 of the ReportActionsList decomposition series (tracker #88320, blueprint PR #87506). PRs 1–3 merged: #88392, #89598, #91048.

Extracts the unread-marker scan logic and the mark-as-read trigger logic out of ReportActionsList.tsx into two new focused hooks.

Pipeline state after PR4. ReportActionsList now consumes: useUnreadMarker, useMarkAsRead, useReportActionsNewActionLiveTail, useReportUnreadMessageScrollTracking, useReportScrollManager, useScrollToEndOnNewMessageReceived, useReportIsArchived, useShouldShowComposerForActiveEditDraft, and others. Remaining: scroll hook (PR5), then PR6 collapses the View into a ReportActions orchestrator.

⚠️ Userspace behavior change

Extracting useUnreadMarker into a standalone, React Compiler–compliant hook required removing the path-dependent prevUnreadMarkerReportActionID state (it read a ref during render, which the compiler rejects in a new file). Dropping it changes one user-visible edge case:

• Before: the "NEW" marker could land on your own just-sent message in this corner — a marker was already shown above someone else's message, that message then became read, and the only remaining unread message was one you just sent yourself. The marker would move onto your own message.
• After: the marker never lands on your own new or just-confirmed message. In that corner it simply clears.

This is the only behavior difference. Everything else (marker placement for others' messages, offline-received messages, pagination anchoring, mark-as-read triggers) is unchanged. The change applies to both the chat report list and the money-request report list, since they share shouldDisplayNewMarkerOnReportAction. This matches the behavior in blueprint PR #87506.

Fixed Issues

$ #89765
PROPOSAL:

Tests

Two hooks (useUnreadMarker, useMarkAsRead) extracted from ReportActionsList.tsx. Aside from the unread-marker edge case documented above (marker no longer lands on your own just-sent message), behavior is unchanged. The plan exercises every behavior the extracted code owns plus the cross-report prevReportID (now module-level), and step L below verifies the edge case explicitly.

A. Unread marker — basic scan

1. Open a chat with 5+ unread messages from another user
2. Verify the red "NEW" marker appears above the first unread message
3. Scroll up past the marker, then back down — marker stays anchored to the same action
4. Mark a message as unread via context menu → marker jumps to that action

B. Unread marker — pagination anchor

1. Open a chat with 50+ unread messages (forces pagination)
2. Verify marker shows on the oldest unread in the first visible page
3. Scroll up to load an older page → marker stays on the original anchor (no stale id)
4. Receive a new message while paginated → marker stays put

C. Unread marker — incoming messages

1. Open a report fully caught up (no marker visible)
2. Scroll up past ACTION_VISIBLE_THRESHOLD
3. Have another user send a message → marker appears above the new message
4. Scroll to bottom → readNewestAction fires, marker clears

D. Unread marker — offline-received messages

1. Go offline
2. Have messages delivered while offline (toggle airplane mode / network)
3. Come back online → marker positioned at the earliest offline-received message

E. Mark as read — initial open

1. Open a report with unread messages while scrolled to bottom
2. Verify readNewestAction fires once on mount
3. Switch to another report and back → does NOT re-fire (initial-mount gate holds)

F. Mark as read — report switch (module-level prevReportID)

1. Open Report A with unread → marks read
2. Without unmounting, navigate to Report B (same ReportActionsList instance is reused)
3. Verify Report B's userActiveSince resets and no stale callbacks from A fire
4. Verify prevReportID === B before any mark-read runs

G. Mark as read — app visibility (web/desktop)

1. Open report with unread, scrolled to bottom, tab focused → marks read
2. Switch browser tab away
3. Receive a new message in background → does NOT mark read
4. Switch back to tab → app-visibility handler fires, marks read
5. readActionSkipped flips correctly when scrolled away from bottom

H. Mark as read — notification referrer (desktop)

1. Receive a push notification, click it → opens report with referrer=NOTIFICATION
2. Verify it marks read even if isVisible returns false (notification center open)
3. Verify the referrer param is cleared after marking read

I. Anonymous user

1. Open a shared report link without signing in
2. Verify no DeviceEventEmitter subscriptions for unreadAction_/readNewestAction_ are created
3. Verify no marker pushdown on incoming messages

J. lastReadTime lazy hydration

1. Sign in fresh — report.lastReadTime initially empty
2. Open the report before Onyx fully loads
3. When lastReadTime resolves, marker recomputes with the real timestamp (not empty string)

K. Floating message counter integration

1. Scroll up, receive new messages → counter shows
2. Tap counter → scrolls to bottom, readActionSkippedRef.current resets to false, readNewestAction is called

L. Unread marker — own-message edge case (behavior change)

1. Open a chat with one unread message from another user → "NEW" marker appears above it
2. Read that message (it falls below lastReadTime) so it is no longer unread
3. Without leaving, send a message yourself while the report still shows the marker context
4. Verify the "NEW" marker does not move onto your own just-sent message — it clears instead (this differs from pre-PR behavior, where the marker would land on your own message)

Regression sanity

• Run A–K on iOS native, Android native, mWeb, MacOS web — same chat with unread + offline mix

• React DevTools Profiler: per-message render count should match pre-PR (no extra commits from the hook split)

• 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

• 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 followed proper code patterns (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
    • If any non-english text was added/modified, I used JaimeGPT to get English > Spanish translation. I then posted it in #expensify-open-source and it was approved by an internal Expensify engineer. Link to Slack message:
  • 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 followed the guidelines as stated in the Review Guidelines
• 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)
• I verified all code is DRY (the PR doesn't include any logic written more than once, with the exception of tests)
• 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
• I verified that if a function's arguments changed that all usages have also been updated correctly
• 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
• If a new CSS style is added I verified that:
  • A similar style doesn't already exist
  • The style can't be created with an existing StyleUtils function (i.e. StyleUtils.getBackgroundAndBorderStyle(theme.componentBG))
• 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 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.
• 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

[adhorodyski]

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[codecov]

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
src/pages/inbox/report/ReportActionsList.tsx	70.27% <75.00%> (-6.07%)	⬇️
src/hooks/useMarkAsRead.ts	95.00% <95.00%> (ø)
src/hooks/useUnreadMarker.ts	94.54% <94.54%> (ø)
... and 30 files with indirect coverage changes