[jmusial]

Details

cache.merge now keeps the cached array when the incoming one is deep-equal, extending #765's reference stability to arrays. Resent, unchanged data becomes a no-op (#768's merged === existing), so subscribers aren't notified and useOnyx doesn't re-render.

• New shouldKeepEqualArrays merge option, on only in cache.merge.
• Arrays inside an object are compared only if nothing else in it changed (otherwise the object changes anyway), so ordinary merges keep their current cost.

Why: on Expensify/App cold start, SearchForTodos resends ~1,350 cached transaction violations (arrays), which made App recompute ~1,000 reports (381 ms).

Proposal on slack here

Perf (reassure): renders on a deep-equal collection merge 2 → 1; existing merge/update/init benchmarks within noise.

Related Issues

Expensify/App#104725

Linked E/App PR

Expensify/App#104984

Automated Tests

The change is convered by unit tests and perf tests. Details in the code.

Manual Tests

Tested on E/App.

Use an account with a few hundred expenses that have violations. Compare this PR's E/App build with main, 5 runs each, using the medians. Spans appear in the JS console as [Sentry][<span name>] Ending span (<N>ms).

Web (desktop and mobile browsers)

1. Open the Inbox and the browser console, filtered on Ending span.
2. Reload the page.
3. Note OnyxDerivedCompute_reportAttributes logged after the SearchForTodos request finished.
4. Open Spend and wait for the expenses to load.
5. Go back to Inbox. Note ManualNavigateToInboxTab.

Native (iOS and Android)

1. Open the Inbox and the JS logs, filtered on Ending span.
2. Force-quit the app, open it again, and wait after the Inbox shows.
3. Note OnyxDerivedCompute_reportAttributes logged after the SearchForTodos request finished.
4. Open Spend and wait for the expenses to load.
5. Go back to Inbox. Note ManualNavigateToInboxTab.

Author Checklist

• I linked the correct issue in the ### Related Issues section above
• I linked the corresponding Expensify/App PR in the ### Linked E/App PR section above, and verified this change against it (E/App CI passed and manual testing completed)
• I wrote clear testing steps that cover the changes made in this PR
  • I added steps for local testing in the Tests section
  • 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 / Chrome
  • iOS / native
  • iOS / 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 the left part of a conditional rendering a React component is a boolean and NOT a string, e.g. myBool && <MyComponent />.
  • 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 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.js 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 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
  • The only data being stored in the state is data necessary for rendering and nothing else
  • If we are not using the full Onyx data that we loaded, I've added the proper selector in order to ensure the component only re-renders when the data it is using changes
  • For Class Components, any internal methods passed to components event handlers are bound to this properly so there are no scoping issues (i.e. for onClick={this.submit} the method this.submit should be bound to this in the constructor)
  • Any internal methods bound to this are necessary to be bound (i.e. avoid this.submit = this.submit.bind(this); if this.submit is never passed to a component event handler like onClick)
  • All JSX used for rendering exists in the render method
  • The component has the minimum amount of code necessary for its purpose, and it is broken down into smaller components in order to separate concerns and functions
• 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 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 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.
• I have checked off every checkbox in the PR author checklist, including those that don't apply to this PR.

Screenshots/Videos

Android: Native

android-native-pr860.mp4

Android: mWeb Chrome

android-chrome-pr860.mp4

iOS: Native

ios-native-pr860.mp4

iOS: mWeb Safari

ios-safari-pr860.mp4

MacOS: Chrome / Safari

web-chrome-pr860.mp4

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-23T17:01:21.360347Z	7128aac	Draft marked ready

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[jmusial]

@blimpich opened it instead of draft, no review required yet. Sorry for noise

[jmusial]

I have read the CLA Document and I hereby sign the CLA

[fabioh8010]

@jmusial could you merge branch with main and provide the E/App PR used to test the changes in Linked E/App PR section?

[jmusial]

@jmusial could you merge branch with main and provide the E/App PR used to test the changes in Linked E/App PR section?

Updated, sorry for missing that part. One thing that after main merge here the E/App s pr is based on Expensify/App#103351

[blimpich]

Commits must have verified signatures.

@jmusial I'm unable to merge because of this. Can you fix this?

[jmusial]

Commits must have verified signatures.

@jmusial I'm unable to merge because of this. Can you fix this?

done

[os-botify]

🚀 Published to npm in 3.0.133 🎉