feat: improve currency rate fallback logic #7606

Prithpal-Sooriya · 2026-01-12T22:17:59Z

Explanation

Modifies CurrencyRateController to better handle fallback currency rates

improved success/error handling (will now try both exchange-rates endpoint then spot prices endpoint for failed networks).

Also decoupled the complex currency fetching logic into separate methods for the main exchange rates fetch vs spot prices fetch.

Oh and also resolve ESLint issues (agent led this)

https://consensys.zoom.us/clips/share/GCgPlIVRRtejh3f0Wgyhmg

References

https://consensyssoftware.atlassian.net/browse/ASSETS-2269
MetaMask/metamask-extension#39194

Checklist

I've updated the test suite for new or updated code as appropriate (Added 5 new tests for partial success/fallback scenarios and updated 2 existing tests to reflect new behavior).
I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate (JSDoc added for new private helper methods).
I've communicated my changes to consumers by updating changelogs for packages I've changed
I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

Note

Improves reliability and structure of exchange rate fetching in CurrencyRateController.

Introduces per-currency fallback: fetch from Price API first, then only failed currencies fall back to token prices; preserves successful results even if fallback fails
Sets explicit null state for currencies missing network config or when Price API returns falsy values; uses helper #createNullRatesForCurrencies
Extracts helpers #fetchRatesFromPriceApi and #fetchRatesFromTokenPricesService; adds FetchRatesResult type; converts fields to private # members
Updates tests: adjusts existing expectations and adds a suite for partial success/fallback scenarios (mixed success, no-fallback-needed, mixed failures)
Updates package CHANGELOG to document the refactor and behavior changes

^{Written by Cursor Bugbot for commit bdec20c. This will update automatically on new commits. Configure here.}

- Refactor #fetchExchangeRatesWithFallback into smaller helper methods: - #fetchRatesFromPriceApi: handles primary Price API call - #fetchRatesFromTokenPricesService: handles fallback fetching - #createNullRatesForCurrencies: creates null entries for failed currencies - Rename private members to use hash syntax (fixing lint errors) - Add partial success handling: when some currencies succeed and others fail, only failed currencies trigger fallback - Add comprehensive tests for partial success scenarios - Update existing tests to match new expected behavior

cursor · 2026-01-12T22:18:00Z

Cursor Agent can help with this pull request. Just @cursor in comments and I'll start working on changes in this branch.
_{Learn more about Cursor Agents}

packages/assets-controllers/src/CurrencyRateController.ts

Removed unused suppressions after refactoring: - no-negated-condition: no longer needed - no-restricted-syntax: no longer needed - @typescript-eslint/explicit-function-return-type: reduced count from 3 to 1

packages/assets-controllers/src/CurrencyRateController.ts

…nd failedCurrencies - Updated #fetchRatesFromTokenPricesService to return { rates, failedCurrencies } similar to #fetchRatesFromPriceApi for consistency - Removed null currency creation from fallback method - failures now add to failedCurrencies instead of creating null rates inline - Step 4 now takes the final list of failed currencies from step 3 to build null rates, simplifying the logic - Simplified #createNullRatesForCurrencies to only take currencies array - Renamed PriceApiResult type to FetchRatesResult for broader applicability

packages/assets-controllers/src/CurrencyRateController.ts

- Wrapped the entire method body in try-catch so it never throws - On any unexpected error, returns all currencies as failed - Updated JSDoc to document that the method is designed to never throw - This allows #fetchExchangeRatesWithFallback to use const instead of let and removes the external try-catch, simplifying the orchestration logic

Co-authored-by: prithpal.sooriya <prithpal.sooriya@consensys.net>

eslint-suppressions.json

Prithpal-Sooriya · 2026-01-13T17:59:30Z

@cursor READ THESE MEMORY FILES:

https://raw.githubusercontent.com/Prithpal-Sooriya/Cloud-Agent-Memory/refs/heads/main/Memory.md

Can you resolve get latest from main and resolve merge conflicts.

cursor · 2026-01-13T17:59:43Z

Done! I've merged the latest from main and resolved the merge conflict.

Summary

Conflict resolved in: packages/assets-controllers/CHANGELOG.md

The conflict was between:

Main branch: New dependency bumps (transaction-controller to ^62.9.1, network-controller to ^28.0.0, accounts-controller to ^35.0.1, polling-controller to ^16.0.1) and Plasma mapping update
This branch: CurrencyRateController refactor entry

Resolution: Combined both by keeping all entries from main and adding our CurrencyRateController entry at the end of the ### Changed section.

All 40 tests pass ✅

_{Learn more about Cursor Agents}

Resolved merge conflict in CHANGELOG.md by combining: - Dependency bumps from main (transaction-controller, network-controller, accounts-controller, polling-controller) - Plasma mapping update from main - CurrencyRateController refactor entry from this branch

Prithpal-Sooriya · 2026-01-14T11:29:22Z

https://github.com/cursor READ THESE MEMORY FILES:

https://raw.githubusercontent.com/Prithpal-Sooriya/Cloud-Agent-Memory/refs/heads/main/Memory.md
Can you resolve get latest from main and resolve merge conflicts.

cursor · 2026-01-14T11:29:34Z

Done! Merged the latest from main and resolved the new conflict.

Summary

New commits from main:

feat: Add watchAsset origin metadata fallbacks (#7612)
feat: adds preferred provider to ramp controller state (#7617)
feat: update asset endpoints to include RWA data (#7548)

Conflict resolved in: packages/assets-controllers/CHANGELOG.md

Combined the new TokensController.watchAsset entry from main with our CurrencyRateController refactor entry.

All 40 tests pass ✅

Resolved merge conflict in CHANGELOG.md by combining: - TokensController.watchAsset metadata fallbacks from main (#7612) - CurrencyRateController refactor entry from this branch (#7606)

Prithpal-Sooriya and others added 2 commits January 12, 2026 21:49

Cursor: Apply local changes for cloud agent

8739076