From 94a157a0cb1e498a2fab4815eb7fde3de6f917d5 Mon Sep 17 00:00:00 2001
From: Maxime OUAIRY <maxime.ouairy-ext@consensys.net>
Date: Thu, 2 Jul 2026 09:07:55 +0200
Subject: [PATCH] fix: unhide tokens with low occurrences for some chains

---
 .../src/data-sources/TokenDataSource.ts       | 26 ++++++++++++++-----
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/packages/assets-controller/src/data-sources/TokenDataSource.ts b/packages/assets-controller/src/data-sources/TokenDataSource.ts
index 836e26bc3e..954656025b 100644
--- a/packages/assets-controller/src/data-sources/TokenDataSource.ts
+++ b/packages/assets-controller/src/data-sources/TokenDataSource.ts
@@ -6,7 +6,7 @@ import type {
 } from '@metamask/phishing-controller';
 import { TokenScanResultType } from '@metamask/phishing-controller';
 import { KnownCaipNamespace, parseCaipAssetType } from '@metamask/utils';
-import type { CaipAssetType } from '@metamask/utils';
+import type { CaipAssetType, CaipChainId } from '@metamask/utils';
 
 import type { AssetsControllerMessenger } from '../AssetsController';
 import { projectLogger, createModuleLogger } from '../logger';
@@ -44,6 +44,12 @@ const BULK_SCAN_BATCH_SIZE = 100;
  */
 const MIN_TOKEN_OCCURRENCES = 3;
 
+const MIN_TOKEN_OCCURRENCES_PER_CHAIN_OVERRIDE: { [key: CaipChainId]: number } =
+  {
+    // Arc: Chain not yet released so some important tokens (ex: EURC) have low occurrences.
+    'eip155:5042': 1,
+  };
+
 /** CAIP-19 `assetNamespace` segments used across filtering logic. */
 export enum CaipAssetNamespace {
   Slip44 = 'slip44',
@@ -415,7 +421,7 @@ export class TokenDataSource {
           metadataResponse.map((a) => [a.assetId, a.occurrences]),
         );
 
-        const evmErc20Ids: string[] = [];
+        const evmErc20Ids: Caip19AssetId[] = [];
         const nonEvmTokenIds: string[] = [];
 
         for (const assetData of metadataResponse) {
@@ -440,12 +446,18 @@ export class TokenDataSource {
         // can import whatever they want and we must keep their metadata even
         // if the API has fewer than `MIN_TOKEN_OCCURRENCES` aggregator hits.
         const allowedEvmIds = new Set(
-          evmErc20Ids.filter(
-            (id) =>
+          evmErc20Ids.filter((id) => {
+            // No exception handling herea as we already managed to parse it upstream.
+            const { chainId } = parseCaipAssetType(id);
+            const minOccurrences =
+              MIN_TOKEN_OCCURRENCES_PER_CHAIN_OVERRIDE[chainId] ??
+              MIN_TOKEN_OCCURRENCES;
+            return (
               customAssetIds.has(id.toLowerCase()) ||
-              (occurrencesByAssetId.get(id) ?? 0) >= MIN_TOKEN_OCCURRENCES ||
-              id.includes(`/erc20:${MUSD_ADDRESS_LOWERCASE}`),
-          ),
+              (occurrencesByAssetId.get(id) ?? 0) >= minOccurrences ||
+              id.includes(`/erc20:${MUSD_ADDRESS_LOWERCASE}`)
+            );
+          }),
         );
 
         // Non-EVM: Blockaid bulk scan.