perf: precompute RBR transaction set in MoneyRequestReportTransactionList

[TMisiukiewicz]

Explanation of Change

Opening a money request report with many transactions was spending ~2s inside compareByRBR on iOS for 1.6k transactions. The root cause: the sort comparator called transactionHasRBR(a) and transactionHasRBR(b) for every pair the sort visited — each call walks the reportActions record via .some, making the total cost O(n log n · R) where R is the number of report actions per transaction.

Fix: before sorting, do a single O(n) pass over transactions and build a Set of every RBR-flagged transaction. The comparator then becomes two Set.has lookups — O(1) per pair. Total RBR classification cost drops from O(n log n · R) to O(n · R), and the Set is only computed when the default sort (Date/ASC) is active.

ManualOpenReport for the report with 1.6k transactions on iOS: 7s -> 5.1s

Fixed Issues

$ #91714
PROPOSAL:

Tests

1. Create new report
2. Add two expenses to the report and force the second one of them to have a violation
3. Go to Spend -> Reports
4. Open the created report
5. Verify you have the default sort (Date/ASC) set
6. Verify the RBR-flagged transaction appear at the top
7. Change sort to Total and confirm the RBR pre-sort is gone
8. Switch back to Date/ASC and verify RBR-flagged item is back on the top

• 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

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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
...stReportView/MoneyRequestReportTransactionList.tsx	0.31% <0.00%> (-0.02%)	⬇️
... and 9 files with indirect coverage changes

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[aimane-chnaif]

Lint failing

[MelvinBot]

Code Review: Looks good. The optimization is sound and behaviorally equivalent to the old approach.

Review details

Correctness: The old compareByRBR returns 0 when both transactions share the same RBR status, then the caller falls through to compareValues. The new Set-based check does exactly the same — it only returns -1/1 when aHasRBR !== bHasRBR, otherwise falls through. Sort order is identical.

Performance: Old code called transactionHasRBR ~2×N×log(N) times (twice per sort comparison). New code calls it exactly N times in the precompute step, then uses O(1) Set.has during sort. Meaningful win for large transaction lists.

useMemo deps: Both memos have correct and complete dependency arrays. rbrTransactionIDs captures all upstream values, so sortedTransactions correctly replaces the old direct deps with just rbrTransactionIDs.

Null guard: rbrTransactionIDs returns null when !isDefaultSort || !allTransactionViolations, matching the old if (isDefaultSort && allTransactionViolations) guard.

No dead code: compareByRBR is still used in MoneyRequestReportPreviewContent.tsx.

Note on ESLint failure: The lint error is in tests/unit/Search/SearchQueryUtilsTest.ts:20 (getKeywordQueryWithCurrentSearchContext unused) — unrelated to this PR.

[trjExpensify]

PR doesn’t need product input as a performance PR. Unassigning and unsubscribing myself.

[MelvinBot]

No regressions found. The change is functionally equivalent to the original compareByRBR behavior.

Investigation details

Sort behavior preserved: compareByRBR (source) has no secondary sorting logic — it simply calls transactionHasRBR on both transactions and returns -1, 1, or 0 based on whether they differ in RBR status. The new Set.has() approach replicates this exactly: if (aHasRBR !== bHasRBR) return aHasRBR ? -1 : 1, then falls through to compareValues — same as the old 0 return.

transactionHasRBR call is correct: The PR's call passes (transaction, violations, login, accountID, report, policy, reportActionsMap) which matches the function signature exactly, including the optional reportActions parameter.

compareByRBR still needed elsewhere: It's still imported in MoneyRequestReportPreviewContent.tsx, so the export from TransactionPreviewUtils.ts correctly remains. The PR only removes the import from MoneyRequestReportTransactionList.tsx.

No test changes needed: Existing tests for compareByRBR and transactionHasRBR in TransactionPreviewUtils.test.ts remain valid since those functions are unchanged.

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Thank you

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

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[OSBotify]

🚀 Deployed to staging by https://github.com/mountiny in version: 9.3.84-0 🚀

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

Bundle Size Analysis (Sentry):

• Android
• iOS

[MelvinBot]

No help site changes are required for this PR.

This is a performance optimization that precomputes RBR-flagged transaction IDs into a Set before sorting, replacing per-comparison transactionHasRBR calls with O(1) Set.has lookups. There are no new features, UI changes, or user-facing behavior changes that would affect documentation.

@TMisiukiewicz, please review the linked help site PR and confirm it reflects the current behavior. Then mark the linked help site PR Ready for review

[jponikarchuk]

This PR failing because of the issue #91935
This issue is reproducible in: All platforms

[OSBotify]

🚀 Deployed to staging by https://github.com/mountiny in version: 9.3.86-0 🚀

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

Bundle Size Analysis (Sentry):

• Android
• iOS

[MelvinBot]

I reviewed the changes in this PR. This is a performance optimization only — it precomputes a Set of RBR-flagged transaction IDs before sorting instead of recalculating RBR status inside the sort comparator for every pair comparison.

No help site changes are required. There are no user-facing behavior changes, no new features, no UI modifications, and no terminology updates — just an internal optimization to reduce sort cost from O(n log n · R) to O(n · R).

@TMisiukiewicz, please review the linked help site PR and confirm it reflects the current behavior. Then mark the linked help site PR Ready for review

[OSBotify]

🚀 Deployed to staging by https://github.com/mountiny in version: 9.3.88-0 🚀

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

Bundle Size Analysis (Sentry):

• Android
• iOS

[MelvinBot]

No help site changes are required for this PR.

This is a performance optimization that precomputes a Set of RBR-flagged transaction IDs before sorting, replacing repeated per-comparison calls with O(1) Set.has lookups. The change is entirely internal to MoneyRequestReportTransactionList.tsx — no user-facing behavior, UI, feature names, or workflows are affected.

@TMisiukiewicz, please review the linked help site PR and confirm it reflects the current behavior. Then mark the linked help site PR Ready for review

[OSBotify]

🚀 Deployed to production by https://github.com/mountiny in version: 9.3.88-2 🚀

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