Description

Fixes two issues that prevented non-EVM (Solana) tokens from working in the Buy flow and caused unnecessary friction when switching between tokens:

1. Case-sensitive assetId mismatch for non-EVM tokens

useRampsPaymentMethods was blanket-lowercasing selectedToken.assetId before passing it to /payments, and BuildQuote was forwarding the raw controller-state assetId into /quotes. The blanket lowercase was originally added in #28399 to normalize EVM EIP-55 checksummed hex addresses (which the server stores lowercase), but it mangles CAIP-19 references from namespaces where case is significant — notably Solana (base58 mint addresses). With a lowercased mint, the server's strict-equality crypto filter in RegionsV2Service returned zero matches and short-circuited to payments: [], so every Solana token appeared to have no payment methods.

This PR introduces normalizeAssetIdForApi which only lowercases when the CAIP-19 namespace is eip155:, preserving case for non-EVM namespaces (solana, bip122, …). It's wired into both useRampsPaymentMethods and BuildQuote's quoteFetchParams, so the EVM normalization from #28399 still applies while non-EVM asset IDs pass through verbatim. Wiring /quotes symmetrically also closes a latent version of the same EVM bug on the quotes endpoint that #28399 only patched for /payments.

2. "Token Not Available" modal blocked manual-provider users from switching tokens

When the selected token wasn't supported by the current provider, the BuildQuote auto-switch effect was gated on providerAutoSelected — it only silently switched to a supporting provider if the current provider had been system-picked. A user who had manually chosen (e.g.) Transak and then navigated back to token selection and picked a Solana token got the "Token Not Available" modal even when another provider (e.g. Coinbase) supported the token.

The gate is removed. The auto-switch effect now runs whenever isTokenUnavailable fires and the modal only appears when no provider supports the token. Manual provider picks remain sticky for any token the provider can actually serve, because the effect still early-returns when !isTokenUnavailable.

Changelog

CHANGELOG entry: Fixed empty payment methods and false "Token Not Available" modal for Solana and other non-EVM tokens in the Buy flow; a manually-selected provider now silently switches to a supporting provider when the selected token isn't supported, instead of blocking the user with the unavailability modal.

Related issues

Fixes: TRAM-3463

Manual testing steps

Feature: Buy flow supports non-EVM tokens and auto-switches providers

  Scenario: User buys a Solana token whose mint has mixed-case base58
    Given the user is in a region that supports Solana tokens (e.g. us-tx)
    And the user is on the BuildQuote screen

    When the user opens token selection and picks dogwifhat (WIF)
    Then the BuildQuote screen loads payment methods successfully
    And the "Token Not Available" modal does not appear

  Scenario: Manually-selected provider stays when it supports the token
    Given the user has manually selected Transak in the provider picker
    And the currently selected token is USDC on Ethereum

    When the user navigates away and comes back to BuildQuote
    Then Transak remains selected
    And payment methods load normally

  Scenario: Manually-selected provider silently switches when it cannot serve the token
    Given the user has manually selected Transak in the provider picker
    And Transak supports the current token
    And Coinbase is also available in the region and supports Solana WIF

    When the user opens token selection and picks Solana WIF
    Then the provider silently switches from Transak to Coinbase
    And payment methods for Coinbase load on the BuildQuote screen
    And the "Token Not Available" modal does not appear

  Scenario: Modal still appears when no provider supports the token
    Given the user is on BuildQuote with any provider selected
    And no available provider supports the chosen token

    When payment methods settle with an empty result
    Then the "Token Not Available" modal appears after the 600ms debounce
    And the user can tap "Change token" or "Change provider"

  Scenario: EVM checksummed assetId still resolves correctly (regression guard)
    Given the user is in us-tx with Transak selected
    And the controller emits USDC as an EIP-55 checksummed assetId

    When the user lands on BuildQuote with USDC selected
    Then payment methods load and the /payments request carries the assetId in lowercase hex
    And the "Token Not Available" modal does not appear

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Mobile Coding Standards.
• I've completed the PR template to the best of my ability
• I've included tests if applicable
• I've documented my code using JSDoc format if applicable
• I've applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Performance checks (if applicable)

• I've tested on Android
  • Ideally on a mid-range device; emulator is acceptable
• I've tested with a power user scenario
  • Use these power-user SRPs to import wallets with many accounts and tokens
• I've instrumented key operations with Sentry traces for production performance metrics
  • See trace() for usage and addToken for an example

For performance guidelines and tooling, see the Performance Guide.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.