feat(assets-controller): add balance state in snaps request

oxlint-suppressions.json

@@ -816,15 +816,6 @@
   "packages/assets-controller/src/data-sources/SnapDataSource.test.ts": {
     "no-useless-return": {
       "count": 1
-    },
-    "typescript/no-unsafe-assignment": {
-      "count": 6
-    },
-    "typescript/no-unsafe-member-access": {
-      "count": 1
-    },
-    "typescript/no-unsafe-return": {
-      "count": 1
     }
   },
   "packages/assets-controller/src/data-sources/SnapDataSource.ts": {
@@ -2553,7 +2544,7 @@
       "count": 1
     },
     "typescript/no-unsafe-assignment": {
-      "count": 9
+      "count": 11
     },
     "typescript/no-unsafe-member-access": {
       "count": 2

packages/assets-controller/CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- Temporarily extend `SnapDataSource` v6 balance fetches, in a deletable block, to also request every token already stored in balance state for the requested chains, so a rollback to Snaps still refreshes tokens that Accounts API and the websocket already support. Remove that block once balance reads fully move to Accounts API ([#10819](https://github.com/MetaMask/core/pull/10819))
 - Bump `@metamask/keyring-api` from `^24.1.0` to `^24.3.0` ([#10792](https://github.com/MetaMask/core/pull/10792), [#10844](https://github.com/MetaMask/core/pull/10844))
 - Bump `@metamask/keyring-internal-api` from `^12.1.0` to `^12.1.2` ([#10792](https://github.com/MetaMask/core/pull/10792), [#10844](https://github.com/MetaMask/core/pull/10844))
 - Bump `@metamask/keyring-snap-client` from `^10.0.0` to `^10.0.1` ([#10792](https://github.com/MetaMask/core/pull/10792))

packages/assets-controller/docs/decisions/2026-09-23-accounts-api-v6-integration.md

@@ -142,8 +142,13 @@ The requests differ as well:
   in full from state. RPC always stamps `full`: resolved tokens get a fresh
   amount, unread tokens keep the amount already in state, and a chain that
   resolved nothing is listed in `errors` instead of writing an empty slice.
-  Snap `#fetchV6` requests visible assets with listed holdings, stamps `full`,
-  and fills omitted visible assets from current state (`0` if none). An empty
+  Snap `#fetchV6` requests listed holdings and visible assets, stamps `full`,
+  and fills omitted visible assets from current state (`0` if none). A separate
+  temporary block also requests every token already in balance state for those
+  chains. A token the snap omits stays out of the snapshot. Accounts API and
+  the websocket already cover more tokens than the snap lists, so a chain that
+  rolls back to the snap still refreshes them. Delete that block once balance
+  reads fully move to Accounts API. An empty
   `getAccountBalances` map (or a thrown fetch) contributes nothing, so last-
   known amounts are kept. Background Snap and
   RPC both stamp `full`. `mergeDataResponses` promotes `full` if any source did.
@@ -184,7 +189,7 @@ flowchart TB
     V6A["Subscribe each source with accounts + assigned chains only"]
     V6WS["Account Activity · event deltas · merge"]
     V6API["Accounts API · visibility from state · full"]
-    V6SNAP["Snap · visible assets from state · full snapshot<br/>balance events stay merge"]
+    V6SNAP["Snap · visible assets · full snapshot<br/>temporary balance-state tokens<br/>balance events stay merge"]
     V6RPC["RPC · visible assets from state · full"]
     V6A --> V6WS
     V6A --> V6API