feat: improve rpc data source (#8385)

## Explanation

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## References

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## Checklist

- [ ] I've updated the test suite for new or updated code as appropriate
- [ ] I've updated documentation (JSDoc, Markdown, etc.) for new or
updated code as appropriate
- [ ] I've communicated my changes to consumers by [updating changelogs
for packages I've
changed](https://github.com/MetaMask/core/tree/main/docs/processes/updating-changelogs.md)
- [ ] I've introduced [breaking
changes](https://github.com/MetaMask/core/tree/main/docs/processes/breaking-changes.md)
in this PR and have prepared draft pull requests for clients and
consumer packages to resolve them

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Changes token detection and RPC metadata behavior by replacing
`TokenListController:getState` with live Tokens API fetches (with
caching/fallback), which can affect detected tokens and metadata
availability when the API is slow or unavailable.
> 
> **Overview**
> **Token detection now pulls its token list from the Tokens API instead
of `TokenListController`.** `TokenDetector` takes a new
`TokensApiClient`, fetches `/v3/chains/{chain}/assets`, caches results
per chain, and falls back to stale cache on API errors (logging
failures).
> 
> `RpcDataSource` and `AssetsController` drop
`TokenListController:getState` from allowed actions and remove
token-list-based ERC-20 metadata fallbacks; unknown ERC-20s are omitted
from `assetsInfo` until downstream enrichment. Tests/fixtures are
updated accordingly, and a new `TokensApiClient` (plus unit tests) is
added and exported.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
9baa7da. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: salimtb

eslint-suppressions.json

@@ -174,9 +174,6 @@
     }
   },
   "packages/assets-controller/src/__fixtures__/MockAssetControllerMessenger.ts": {
-    "import-x/no-relative-packages": {
-      "count": 1
-    },
     "no-restricted-syntax": {
       "count": 4
     }
@@ -188,7 +185,7 @@
   },
   "packages/assets-controller/src/data-sources/RpcDataSource.ts": {
     "no-restricted-syntax": {
-      "count": 3
+      "count": 2
     }
   },
   "packages/assets-controller/src/data-sources/SnapDataSource.ts": {

packages/assets-controller/CHANGELOG.md

@@ -9,6 +9,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- `TokenDetector` now fetches the token list directly from the Tokens API (`/v3/chains/{chain}/assets`) via a new `TokensApiClient` instead of reading from `TokenListController:getState` ([#8385](https://github.com/MetaMask/core/pull/8385))
+  - `TokenDetectorMessenger` type has been removed; `TokenDetector` constructor now takes a `TokensApiClient` instance as its second argument
+  - `RpcDataSource` no longer requires `TokenListController:getState` — `GetTokenListState` has been removed from `RpcDataSourceAllowedActions` and `AssetsControllerAllowedActions`
+  - Unknown ERC-20 metadata is no longer looked up from the token list as a fallback in `RpcDataSource`; `TokenDataSource` handles enrichment downstream
 - Split `getAssets` fetch pipeline into a fast awaited path and a parallel fire-and-forget background path to reduce perceived latency on unlock and onboarding ([#8383](https://github.com/MetaMask/core/pull/8383))
   - Fast pipeline: AccountsApi + StakedBalance → Detection → Token + Price (awaited, committed to state immediately)
   - Background pipeline: Snap + RPC run in parallel → Detection → Token + Price when basic functionality is enabled; when disabled (RPC-only mode), Token + Price are omitted (fire-and-forget merge)

packages/assets-controller/src/AssetsController.test.ts

@@ -178,13 +178,6 @@ async function withController<ReturnValue>(
   ).registerActionHandler('NetworkController:getNetworkClientById', () => ({
     provider: {},
   }));
-  (
-    messenger as {
-      registerActionHandler: (a: string, h: () => unknown) => void;
-    }
-  ).registerActionHandler('TokenListController:getState', () => ({
-    tokensChainsCache: {},
-  }));
 
   if (clientControllerState !== undefined) {
     (
@@ -292,13 +285,6 @@ describe('AssetsController', () => {
       ).registerActionHandler('NetworkController:getNetworkClientById', () => ({
         provider: {},
       }));
-      (
-        messenger as {
-          registerActionHandler: (a: string, h: () => unknown) => void;
-        }
-      ).registerActionHandler('TokenListController:getState', () => ({
-        tokensChainsCache: {},
-      }));
 
       const controller = new AssetsController({
         messenger: messenger as unknown as AssetsControllerMessenger,
@@ -393,13 +379,6 @@ describe('AssetsController', () => {
       ).registerActionHandler('NetworkController:getNetworkClientById', () => ({
         provider: {},
       }));
-      (
-        messenger as {
-          registerActionHandler: (a: string, h: () => unknown) => void;
-        }
-      ).registerActionHandler('TokenListController:getState', () => ({
-        tokensChainsCache: {},
-      }));
 
       expect(
         () =>

packages/assets-controller/src/AssetsController.ts

@@ -2,7 +2,6 @@ import type {
   AccountTreeControllerGetAccountsFromSelectedAccountGroupAction,
   AccountTreeControllerSelectedAccountGroupChangeEvent,
 } from '@metamask/account-tree-controller';
-import type { GetTokenListState } from '@metamask/assets-controllers';
 import { BaseController } from '@metamask/base-controller';
 import type {
   ControllerGetStateAction,
@@ -267,7 +266,6 @@ type AllowedActions =
   // AssetsController
   | AccountTreeControllerGetAccountsFromSelectedAccountGroupAction
   // RpcDataSource
-  | GetTokenListState
   | NetworkControllerGetStateAction
   | NetworkControllerGetNetworkClientByIdAction
   // RpcDataSource, StakedBalanceDataSource

packages/assets-controller/src/__fixtures__/MockAssetControllerMessenger.ts

@@ -8,12 +8,12 @@ import {
   MockAnyNamespace,
 } from '@metamask/messenger';
 import { NetworkStatus } from '@metamask/network-controller';
-
 import {
   NetworkState,
   RpcEndpoint,
   RpcEndpointType,
-} from '../../../network-controller/src/NetworkController';
+} from '@metamask/network-controller/src/NetworkController';
+
 import {
   AssetsControllerMessenger,
   getDefaultAssetsControllerState,
@@ -53,7 +53,6 @@ export function createMockAssetControllerMessenger(): {
       'AccountTreeController:getAccountsFromSelectedAccountGroup',
       'AssetsController:getState',
       // RpcDataSource
-      'TokenListController:getState',
       'NetworkController:getState',
       'NetworkController:getNetworkClientById',
       // RpcDataSource, StakedBalanceDataSource
@@ -173,10 +172,6 @@ export function registerRpcDataSourceActions(
     getDefaultAssetsControllerState(),
   );
 
-  rootMessenger.registerActionHandler('TokenListController:getState', () => ({
-    tokensChainsCache: {},
-  }));
-
   rootMessenger.registerActionHandler(
     'NetworkEnablementController:getState',
     () => ({