fix: Blockscout and Etherscan lookups are off until the user turns them on (closes #668)

Out of the box the wallet sent the user's addresses to Blockscout. It sent each
recipient to Etherscan for its label. Two settings, "Use Blockscout" and "Check
recipients on Etherscan", now gate those requests. Both are off in a new install
and offered unticked on Welcome and in Settings. While one is off, the screens
that relied on it say so in a plain line. Each gated request reads its setting
from storage before it asks and when the answer lands. An answer that lands
after the setting went off is dropped. An open popup takes a change another page
saved and draws its screens again. While "Use Blockscout" is off, no address
keeps an untracked token. ENS lookups ask only the RPC endpoint.

Model: opus-5-5

README.md

@@ -893,6 +893,8 @@ src/
     prices.js         — ETH/USD and token/USD via CoinDesk API
     scamlist.js       — known fraud contract addresses
     state.js          — persisted state (extension storage)
+    storedSettings.js — "Use Blockscout" and "Check recipients on Etherscan",
+                        read from storage by the requests they gate
     symbolSpoof.js    — the known-symbol spoof rule, shared by all surfaces
     tokenList.js      — top ERC-20 tokens by market cap (hardcoded)
     transactions.js   — tx history fetching + anti-poisoning filters
@@ -1440,9 +1442,9 @@ setting is off until the user turns it on. While it is off:
 - A tracked token's balance uses the decimals from the bundled list, or else the
   decimals saved when the token was tracked.
 
-Each refresh, in the popup or the background, reads the stored setting when it
-starts. If the setting is off when the refresh saves, the save drops every token
-the user has not tracked.
+Blockscout may answer just before the user turns the setting off. So if the
+stored setting is off when the refresh saves, in the popup or the background,
+the save drops every token the user has not tracked.
 
 A tracked token is shown when its balance is nonzero, and any other ERC-20 when
 its balance is nonzero and it is in the bundled known-token list or has 1,000 or
@@ -1916,13 +1918,14 @@ view would leave a wallet one click from deletion.
 - **Transitions**:
     - "Review" (valid inputs, ENS resolved) → **ConfirmTx**
     - "Review" with an unresolvable ENS name or an invalid amount → flash
-      message, no screen change. An amount is valid when it is a number above
-      zero, written as digits with at most one decimal point, with nothing but
-      zeros after the token's last decimal place. ETH has 18 places, and a token
-      with more, or with an unknown number, is held to 18. Zeros past those
-      places leave the amount unchanged, so `1.0000000` of a 6-place token
-      passes and is sent as exactly 1. ConfirmTx makes the same check before
-      anything can be sent
+      message, no screen change. A name with no address, or one resolved
+      off-chain, gets "That ENS name has no on-chain address." An amount is
+      valid when it is a number above zero, written as digits with at most one
+      decimal point, with nothing but zeros after the token's last decimal
+      place. ETH has 18 places, and a token with more, or with an unknown
+      number, is held to 18. Zeros past those places leave the amount unchanged,
+      so `1.0000000` of a 6-place token passes and is sent as exactly 1.
+      ConfirmTx makes the same check before anything can be sent
     - "Back" → previous screen (Home, AddressDetail, or AddressToken)
 
 #### ConfirmTx (`confirm-tx`)
@@ -2798,6 +2801,10 @@ settings:
 Both settings are on the Welcome screen and in Settings. Both are off in a new
 install. Each setting applies to every network.
 
+A request that either setting gates reads the setting from storage before it
+asks, and again when the answer lands. While the setting is off, nothing is
+asked, and an answer that lands is dropped.
+
 Contacted by default:
 
 - **Ethereum JSON-RPC endpoint**: The extension needs an Ethereum node to query
@@ -2833,22 +2840,26 @@ Sent the user's data only while the user has turned the setting on:
         - token holder counts, for spam filtering
         - a transaction's block, network details and calldata, for
           TransactionDetail
+    - **Contacted**, while the setting is on:
+        - on every balance refresh, in the popup and in the background
+        - when Home, AddressDetail or AddressToken loads its history
+        - when TransactionDetail opens
     - **While the setting is off**: each of those screens shows a line saying
       what it leaves out and that "Use Blockscout" is off. Only tracked tokens
       are listed.
-    - **Saving the URL**: pressing "Save" beside the URL in Settings asks that
-      URL for `/stats`. This request carries no user data. It is made whether or
-      not the setting is on.
+    - **Saving the URL**: whether or not the setting is on, pressing "Save"
+      beside the URL in Settings asks that URL for `/stats`. This request
+      carries no user data.
     - **Data sent**: Ethereum addresses, and the hash of each transaction the
       user opens. Blockscout receives the user's addresses to query their
       transaction history and token balances. No private keys, passwords, or
       signing operations are sent.
 
-- **Etherscan address labels** ("Check recipients on Etherscan"): When
-  confirming a transaction, the extension performs a best-effort lookup of the
-  recipient address on Etherscan to check for phishing/scam labels. This is a
-  direct page fetch with no API key; the user's browser makes the request. While
-  the setting is off, ConfirmTx says that no Etherscan check was made.
+- **Etherscan address labels** ("Check recipients on Etherscan"): While the
+  setting is on, ConfirmTx looks up the recipient's address on Etherscan each
+  time it is shown. It checks for a phishing or scam label, best-effort. This is
+  a direct page fetch with no API key; the user's browser makes the request.
+  While the setting is off, ConfirmTx says that no Etherscan check was made.
     - **Data sent**: the recipient's address and nothing else.
 
 The etherscan links on the screens open a page in the browser when the user

docs/README.md

@@ -90,10 +90,10 @@ this in Settings to any Ethereum JSON-RPC endpoint, including your own local
 node.
 
 When it is contacted: on every balance refresh (every 10 seconds while the popup
-is open, every 60 seconds in the background), when you type an ENS name into the
-Send screen, when a send is prepared and broadcast, while a pending transaction
-is polled for its receipt, and for the reverse ENS lookups used to label
-addresses (cached for 12 hours).
+is open, every 60 seconds in the background), when you review a send to an ENS
+name, when a send is prepared and broadcast, while a pending transaction is
+polled for its receipt, and for the reverse ENS lookups used to label addresses
+(cached for 12 hours).
 
 What gets sent: standard Ethereum JSON-RPC requests (balance queries,
 transaction broadcasts, gas estimates, ENS lookups, contract-code checks). Your
@@ -102,8 +102,8 @@ addresses are necessarily visible to the RPC provider when querying balances.
 **Blockscout API** (default: `eth.blockscout.com/api/v2`;
 `eth-sepolia.blockscout.com/api/v2` on Sepolia)
 
-Blockscout is an open-source blockchain explorer. AutistMask uses it only while
-"Use Blockscout" is on. It then asks Blockscout for:
+Blockscout is an open-source blockchain explorer. AutistMask sends it your data
+only while "Use Blockscout" is on. It then asks Blockscout for:
 
 - your recent transactions and token transfers
 - the balances of the tokens you have not tracked, with the holder counts used
@@ -121,9 +121,9 @@ When it is contacted, while "Use Blockscout" is on:
 - whenever a screen showing transaction history is opened
 - when you open a transaction
 
-Pressing "Save" beside the Blockscout URL in Settings also contacts it, even
-with the setting off. That request checks the URL by asking it for `/stats`. It
-sends none of your data.
+Whether or not the setting is on, pressing "Save" beside the Blockscout URL in
+Settings asks that URL for `/stats` to check it. That request sends none of your
+data.
 
 What gets sent: your Ethereum addresses (to look up balances and transactions)
 and the hash of each transaction you open.
@@ -143,14 +143,15 @@ address.
 
 **Etherscan address labels** (`etherscan.io`; `sepolia.etherscan.io` on Sepolia)
 
-When you review a send, AutistMask fetches the recipient's public Etherscan
-address page. It looks for a "Fake_Phishing"/"Phish/Hack" label or a scam
-warning, and shows a red warning if it finds one. This is a plain page fetch
-with no API key, made by your browser. It is best-effort: if it fails, it is
-silently ignored. This endpoint is not user-configurable.
+While "Check recipients on Etherscan" is on, AutistMask fetches the recipient's
+public Etherscan address page when you review a send. It looks for a
+"Fake_Phishing"/"Phish/Hack" label or a scam warning, and shows a red warning if
+it finds one. This is a plain page fetch with no API key, made by your browser.
+It is best-effort: if it fails, it is silently ignored. This endpoint is not
+user-configurable.
 
-The check is off until you turn on "Check recipients on Etherscan". While the
-setting is off, the confirmation screen says that no Etherscan check was made.
+The setting is off in a new install. While it is off, the confirmation screen
+says that no Etherscan check was made.
 
 When it is contacted: only while "Check recipients on Etherscan" is on, each
 time you reach the send confirmation screen.
@@ -271,7 +272,8 @@ screen. Tokens can also be added from Settings, under "Tracked Tokens".
 1. Click "Send" from the home screen or an address detail view.
 2. Select what to send (ETH, or any ERC-20 token with a balance on this address
    that survives the spam filters).
-3. Enter the recipient address or ENS name (e.g. `vitalik.eth`).
+3. Enter the recipient address or ENS name (e.g. `vitalik.eth`). AutistMask does
+   not look up a name resolved off-chain, so enter its address instead.
 4. Enter the amount, or click "Max" to fill it in: a token's balance, cut to 18
    decimal places, or your ETH balance minus the amount reserved for the network
    fee.

src/background/index.js

@@ -1391,9 +1391,9 @@ const RECENT_BALANCE_REFRESH_MS = Math.floor(BALANCE_REFRESH_PERIOD_MS / 2);
 // lastBalanceRefresh is left as the switch set it, so the next tick refreshes
 // the new network.
 //
-// The refresh asks Blockscout only if "Use Blockscout" is on when it starts.
-// The user may turn it off while the refresh runs. So when "Use Blockscout"
-// stored NOW is off, the save drops every token the user has not tracked.
+// Blockscout may have answered before the user turned "Use Blockscout" off. So
+// when "Use Blockscout" stored NOW is off, the save drops every token the user
+// has not tracked.
 async function backgroundRefresh() {
     const s = await getState();
     const now = Date.now();
@@ -1405,7 +1405,6 @@ async function backgroundRefresh() {
         wallets,
         s.rpcUrl,
         s.blockscoutUrl,
-        s.useBlockscout,
         s.trackedTokens,
         s.networkId,
     );

src/popup/index.js

@@ -71,9 +71,8 @@ let refreshInFlight = false;
 // the recovery screen: there is no profile left to refresh.
 let refreshTimer = null;
 
-// The refresh first takes any change to the network or to "Use Blockscout"
-// saved elsewhere (followStoredSettings() below). So it asks Blockscout only if
-// the stored setting is on when it starts.
+// The refresh first takes any change to the network or to either setting saved
+// elsewhere (followStoredSettings() below), so what it draws follows them.
 //
 // The refresh writes into a copy of the wallets. Inside the save, under the
 // lock, its results are copied onto the address records in `state` only if the
@@ -85,8 +84,9 @@ let refreshTimer = null;
 // previous network's must not come back over them
 // (https://git.eeqj.de/sneak/AutistMask/issues/577). A dropped refresh is not
 // recorded as done. Results are copied by address, so an address added or
-// removed meanwhile is left as it is. If the stored "Use Blockscout" is off
-// when the refresh saves, the save drops every token the user has not tracked.
+// removed meanwhile is left as it is. Blockscout may have answered before the
+// user turned "Use Blockscout" off. So if the stored setting is off when the
+// refresh saves, the save drops every token the user has not tracked.
 async function doRefreshAndRender() {
     if (refreshInFlight) return;
     refreshInFlight = true;
@@ -100,7 +100,6 @@ async function doRefreshAndRender() {
                 wallets,
                 state.rpcUrl,
                 state.blockscoutUrl,
-                state.useBlockscout,
                 state.trackedTokens,
                 networkId,
                 pageClosed.signal,

src/popup/views/addressDetail.js

@@ -102,7 +102,6 @@ async function loadTransactions(address) {
         const rawTxs = await fetchRecentTransactions(
             address,
             state.blockscoutUrl,
-            state.useBlockscout,
             currentNetwork().chainId,
         );
         const result = filterTransactions(rawTxs, {

src/popup/views/addressToken.js

@@ -174,7 +174,6 @@ async function loadTransactions(address, tokenId) {
         const rawTxs = await fetchRecentTransactions(
             address,
             state.blockscoutUrl,
-            state.useBlockscout,
             currentNetwork().chainId,
         );
         const result = filterTransactions(rawTxs, {

src/popup/views/home.js

@@ -197,7 +197,6 @@ async function loadHomeTxs(ctx) {
             fetchRecentTransactions(
                 addr,
                 state.blockscoutUrl,
-                state.useBlockscout,
                 currentNetwork().chainId,
             ),
         );

src/popup/views/send.js

@@ -403,8 +403,11 @@ function init(_ctx) {
             try {
                 const provider = getProvider(state.rpcUrl, state.networkId);
                 const resolved = await provider.resolveName(to);
+                // getProvider() does not look up a name resolved off-chain,
+                // so such a name comes back with no address too. The message
+                // covers both, in the one line the flash area shows.
                 if (!resolved) {
-                    showFlash("That ENS name has no address.");
+                    showFlash("That ENS name has no on-chain address.");
                     return;
                 }
                 resolvedTo = resolved;

src/popup/views/transactionDetail.js

@@ -26,6 +26,7 @@ const { state } = require("../../shared/state");
 const { nativeCurrencyByChainId } = require("../../shared/networks");
 const { formatEther, formatUnits } = require("ethers");
 const { log, debugFetch } = require("../../shared/log");
+const { storedSettingIsOn } = require("../../shared/storedSettings");
 const { decodeCalldata } = require("./approval");
 
 /**
@@ -309,10 +310,11 @@ function populateOnChainDetails(txData, chainId) {
 }
 
 // Reads the block, network details and calldata from Blockscout, and decodes
-// the calldata. While "Use Blockscout" is off, Blockscout is not asked and none
-// of them is shown.
+// the calldata. While the stored "Use Blockscout" is off, Blockscout is not
+// asked, and an answer that lands after it went off is dropped
+// (src/shared/storedSettings.js). Either way none of them is shown.
 async function loadFullTxDetails(txHash, chainId) {
-    if (!state.useBlockscout) return;
+    if (!(await storedSettingIsOn("useBlockscout"))) return;
     const section = $("tx-detail-calldata-section");
     const actionEl = $("tx-detail-calldata-action");
     const detailsEl = $("tx-detail-calldata-details");
@@ -328,6 +330,7 @@ async function loadFullTxDetails(txHash, chainId) {
         );
         if (!resp.ok) return;
         const txData = await resp.json();
+        if (!(await storedSettingIsOn("useBlockscout"))) return;
 
         // Populate on-chain detail fields (block, nonce, gas, fee)
         populateOnChainDetails(txData, chainId);

src/shared/balances.js

@@ -22,6 +22,7 @@ const { LOW_HOLDER_THRESHOLD, parseHoldersCount } = require("./holders");
 const { isSpoofedSymbol } = require("./symbolSpoof");
 const { toDecimals } = require("./transferAmount");
 const { resolveTokenDecimals } = require("./approvalAmount");
+const { storedSettingIsOn } = require("./storedSettings");
 
 // Use a static network to skip auto-detection (which can fail and cause
 // "could not coalesce error" on some RPC endpoints like Cloudflare).
@@ -95,9 +96,10 @@ function rawUnits(value) {
 // Fetch token balances for a single address from Blockscout.
 // Returns [{ address, name, symbol, decimals, balance, holders }].
 //
-// `useBlockscout` is the user's "Use Blockscout" setting. While it is off,
-// Blockscout is not asked and the answer is an empty list. So no token the user
-// has not tracked is listed.
+// While the stored "Use Blockscout" is off, Blockscout is not asked, and an
+// answer that lands after it went off is dropped (src/shared/storedSettings.js).
+// Either way the answer is an empty list, so no token the user has not tracked
+// is listed.
 //
 // Filters out spam: only shows tokens that are in the known token list,
 // explicitly tracked by the user, or have >= 1000 holders. A tracked token's
@@ -114,11 +116,10 @@ function rawUnits(value) {
 async function fetchTokenBalances(
     address,
     blockscoutUrl,
-    useBlockscout,
     trackedTokens,
     signal,
 ) {
-    if (!useBlockscout) return [];
+    if (!(await storedSettingIsOn("useBlockscout"))) return [];
     try {
         const resp = await debugFetch(
             blockscoutUrl + "/addresses/" + address + "/token-balances",
@@ -128,6 +129,7 @@ async function fetchTokenBalances(
             return null;
         }
         const items = await resp.json();
+        if (!(await storedSettingIsOn("useBlockscout"))) return [];
         if (!Array.isArray(items)) return null;
 
         const trackedSet = new Set(
@@ -316,13 +318,12 @@ async function fetchTrackedTokenBalances(
 }
 
 // Fetch ETH balances, ENS names, and ERC-20 token balances for all addresses.
-// `trackedTokens` are the tokens tracked on the active network.
-// `useBlockscout` and `signal` are as for fetchTokenBalances().
+// `trackedTokens` are the tokens tracked on the active network. `signal` is as
+// for fetchTokenBalances().
 async function refreshBalances(
     wallets,
     rpcUrl,
     blockscoutUrl,
-    useBlockscout,
     trackedTokens,
     networkId,
     signal,
@@ -391,7 +392,6 @@ async function refreshBalances(
             const explorerRequest = fetchTokenBalances(
                 addr.address,
                 blockscoutUrl,
-                useBlockscout,
                 tracked,
                 signal,
             );

src/shared/etherscanLabels.js

@@ -3,8 +3,7 @@
 // This is a best-effort enrichment: network failures return null silently.
 
 const { networkByChainId } = require("./networks");
-const { storageGet } = require("./browserApi");
-const { normalizePersisted } = require("./persistedState");
+const { storedSettingIsOn } = require("./storedSettings");
 
 // Patterns in the page title that indicate a flagged address.
 // Title format: "Fake_Phishing184810 | Address: 0x... | Etherscan"
@@ -80,11 +79,9 @@ function parseEtherscanPage(html) {
  * when it is omitted: etherscan.io on mainnet, sepolia.etherscan.io on
  * Sepolia.
  *
- * Etherscan is asked only while "Check recipients on Etherscan" is on in the
- * stored profile. The page's own copy of the setting is not used, because
- * another page may have just changed it. The stored setting is read through
- * normalizePersisted(), so it is on only when a load would find it on. While
- * it is off, the answer is null.
+ * While the stored "Check recipients on Etherscan" is off, Etherscan is not
+ * asked, and an answer that lands after it went off is dropped
+ * (src/shared/storedSettings.js). Either way the answer is null.
  *
  * @param {string} address - Ethereum address to check.
  * @param {string} [chainId] - Chain id of the network to look it up on.
@@ -92,8 +89,7 @@ function parseEtherscanPage(html) {
  */
 async function checkEtherscanLabel(address, chainId) {
     try {
-        const { autistmask } = await storageGet("autistmask");
-        if (!normalizePersisted(autistmask).checkRecipientsOnEtherscan) {
+        if (!(await storedSettingIsOn("checkRecipientsOnEtherscan"))) {
             return null;
         }
         // Lazy require to avoid pulling in chrome.storage at module scope
@@ -106,6 +102,9 @@ async function checkEtherscanLabel(address, chainId) {
         });
         if (!resp.ok) return null;
         const html = await resp.text();
+        if (!(await storedSettingIsOn("checkRecipientsOnEtherscan"))) {
+            return null;
+        }
         const result = parseEtherscanPage(html);
         if (result.isPhishing) {
             return {
@@ -117,7 +116,6 @@ async function checkEtherscanLabel(address, chainId) {
         return null;
     } catch {
         // Network errors are expected — Etherscan may rate-limit or block.
-        // A failed storage read lands here too, before Etherscan is asked.
         return null;
     }
 }

src/shared/storedSettings.js

@@ -0,0 +1,24 @@
+// Reads "Use Blockscout" or "Check recipients on Etherscan" from the stored
+// profile.
+//
+// A request that either setting gates reads it here twice: before it asks, and
+// again when the answer lands. While the setting is off, nothing is asked, and
+// an answer that lands is dropped. A page's own copy of the setting is not
+// used, because another page may have just changed it.
+
+const { storageGet } = require("./browserApi");
+const { normalizePersisted } = require("./persistedState");
+
+// Whether `name`, "useBlockscout" or "checkRecipientsOnEtherscan", is on in the
+// stored profile. The profile is read through normalizePersisted(), as a load
+// reads it, so only a stored true is on. A failed read counts as off.
+async function storedSettingIsOn(name) {
+    try {
+        const { autistmask } = await storageGet("autistmask");
+        return normalizePersisted(autistmask)[name];
+    } catch {
+        return false;
+    }
+}
+
+module.exports = { storedSettingIsOn };

src/shared/transactions.js

@@ -21,6 +21,7 @@ const { toDecimals } = require("./transferAmount");
 // detail view is the authoritative record and already shows exact precision.
 const { truncateAmount: formatTxValue } = require("./amountDisplay");
 const { routerRelease } = require("./uniswap");
+const { storedSettingIsOn } = require("./storedSettings");
 
 // Ethereum addresses are case-insensitive: EIP-55 mixed case is a checksum
 // over the address, not part of its identity.  Every address comparison in
@@ -236,16 +237,16 @@ function mergeTransactions(txs, tokenTransfers) {
 // carries it, and a native entry is labelled with that network's
 // `nativeCurrency` from networks.js (`ETH`, `SepoliaETH`).
 //
-// `useBlockscout` is the user's "Use Blockscout" setting. While it is off,
-// Blockscout is not asked and the answer is an empty list.
+// While the stored "Use Blockscout" is off, Blockscout is not asked, and an
+// answer that lands after it went off is dropped (src/shared/storedSettings.js).
+// Either way the answer is an empty list.
 async function fetchRecentTransactions(
     address,
     blockscoutUrl,
-    useBlockscout,
     chainId,
     count = 25,
 ) {
-    if (!useBlockscout) return [];
+    if (!(await storedSettingIsOn("useBlockscout"))) return [];
     log.debugf("fetchRecentTransactions", address);
     const addrLower = normalizeAddress(address);
 
@@ -276,6 +277,7 @@ async function fetchRecentTransactions(
 
     const txJson = txResp.ok ? await txResp.json() : {};
     const ttJson = ttResp.ok ? await ttResp.json() : {};
+    if (!(await storedSettingIsOn("useBlockscout"))) return [];
 
     const txs = mergeTransactions(
         (txJson.items || []).map((tx) => parseTx(tx, addrLower, chainId)),

tests/backgroundStateIsolation.test.js

@@ -412,14 +412,7 @@ describe("a balance refresh under a network switch", () => {
         const ranOn = [];
 
         const bg = loadWorker("sepolia", {
-            refreshBalances: async (
-                wallets,
-                rpcUrl,
-                explorer,
-                useBlockscout,
-                tokens,
-                id,
-            ) => {
+            refreshBalances: async (wallets, rpcUrl, explorer, tokens, id) => {
                 ranOn.push(id);
                 reachedNetwork.resolve();
                 await roundTrip.promise;
@@ -455,22 +448,16 @@ describe("a balance refresh under a network switch", () => {
 
 describe("a balance refresh under a change of Use Blockscout", () => {
     // Turning "Use Blockscout" off drops the tokens the user has not tracked
-    // (src/popup/views/settings.js). A refresh that started while it was on
-    // still saves its balances when it returns, but not those tokens. The same
-    // refresh in the popup is in tests/blockscoutEtherscanSettings.test.js.
+    // (src/popup/views/settings.js). Blockscout may have answered a refresh
+    // just before. That refresh still saves its balances when it returns, but
+    // not those tokens. The same refresh in the popup is in
+    // tests/blockscoutEtherscanSettings.test.js.
     test("a refresh that returns after Use Blockscout was turned off saves its balances without the untracked token", async () => {
         const roundTrip = deferred();
         const started = deferred();
-        const handed = [];
 
         const bg = loadWorker("mainnet", {
-            refreshBalances: async (
-                wallets,
-                rpcUrl,
-                explorer,
-                useBlockscout,
-            ) => {
-                handed.push(useBlockscout);
+            refreshBalances: async (wallets) => {
                 started.resolve();
                 await roundTrip.promise;
                 wallets[0].addresses[0].balance = "7.0";
@@ -504,7 +491,6 @@ describe("a balance refresh under a change of Use Blockscout", () => {
         roundTrip.resolve();
         await refresh;
 
-        expect(handed).toEqual([true]);
         const after = bg.persisted();
         expect(after.wallets[0].addresses[0].balance).toBe("7.0");
         expect(after.wallets[0].addresses[0].tokenBalances).toEqual([]);

tests/balanceRefreshCancelled.test.js

@@ -24,6 +24,12 @@ const TRACKED = {
     decimals: 6,
 };
 
+// Blockscout is asked only while the stored "Use Blockscout" is on.
+const { makeStorageStub } = require("./support/storageStub");
+globalThis.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+};
+
 const realFetch = globalThis.fetch;
 let logged;
 
@@ -54,7 +60,6 @@ function refresh(signal) {
         wallets,
         RPC_URL,
         EXPLORER_URL,
-        true,
         [TRACKED],
         "mainnet",
         signal,

tests/balanceRefreshNetworkSwitch.test.js

@@ -91,7 +91,7 @@ test("a refresh that returns after a switch in Settings writes nothing, and the
 
     await page.tick();
 
-    expect(refreshBalances.mock.lastCall[5]).toBe("sepolia");
+    expect(refreshBalances.mock.lastCall[4]).toBe("sepolia");
     expect(page.storage.read("autistmask").lastBalanceRefresh).toBeGreaterThan(
         0,
     );

tests/blockscoutEtherscanSettings.test.js

@@ -7,9 +7,10 @@
 // the Blockscout URL in Settings. It asks that URL only for `/stats` and sends
 // none of the user's data.
 //
-// The balance refresh and the Etherscan check follow the stored setting, not
-// the page's copy of it. So a change another page saved applies to them at
-// once. An open page also takes such a change and draws its screens again.
+// A request that either setting gates reads the stored setting, not the page's
+// copy, before it asks and again when the answer lands. So a change another
+// page saved applies to it at once. An open page also takes such a change and
+// draws its screens again.
 //
 // Only Blockscout reports the tokens the user has not tracked. While "Use
 // Blockscout" is off, no address keeps them and no screen lists them.
@@ -40,6 +41,7 @@ const {
 } = require("../src/shared/balances");
 const { fetchRecentTransactions } = require("../src/shared/transactions");
 const { getFullWarnings } = require("../src/shared/addressWarnings");
+const { checkEtherscanLabel } = require("../src/shared/etherscanLabels");
 const { HISTORY_OFF_TEXT, escapeHtml } = require("../src/popup/views/helpers");
 
 const RPC_URL = "https://rpc.example.invalid";
@@ -61,6 +63,25 @@ const USDC_ROW = {
     },
 };
 
+// A transfer of 1 ETH from RECIPIENT to ADDRESS, as Blockscout lists it in
+// ADDRESS's history.
+const HISTORY_ITEM = {
+    hash: TX_HASH,
+    block_number: 21000000,
+    timestamp: "2026-02-27T12:00:00.000Z",
+    from: { hash: RECIPIENT },
+    to: { hash: ADDRESS, is_contract: false },
+    value: "1000000000000000000",
+    method: null,
+    status: "ok",
+};
+
+// Etherscan's page for RECIPIENT, which labels it a phishing address.
+const PHISHING_PAGE =
+    "<html><head><title>Fake_Phishing1 | Address: " +
+    RECIPIENT +
+    " | Etherscan</title></head><body></body></html>";
+
 const realFetch = globalThis.fetch;
 
 afterEach(() => {
@@ -91,33 +112,55 @@ describe("where each request is made", () => {
     // Every URL fetch() was asked for, in order.
     let asked;
 
+    // What Blockscout and Etherscan answer: USDC among ADDRESS's tokens,
+    // HISTORY_ITEM in its history, and PHISHING_PAGE for RECIPIENT.
+    function answer(url) {
+        return {
+            ok: true,
+            status: 200,
+            json: async () => {
+                if (url.endsWith("/token-balances")) return [USDC_ROW];
+                if (url.endsWith("/transactions")) {
+                    return { items: [HISTORY_ITEM] };
+                }
+                return { items: [] };
+            },
+            text: async () => PHISHING_PAGE,
+        };
+    }
+
+    async function recordAndAnswer(url) {
+        asked.push(String(url));
+        return answer(String(url));
+    }
+
     beforeEach(() => {
         asked = [];
-        globalThis.fetch = jest.fn(async (url) => {
-            asked.push(String(url));
-            return {
-                ok: true,
-                status: 200,
-                json: async () =>
-                    String(url).endsWith("/token-balances")
-                        ? [USDC_ROW]
-                        : { items: [] },
-                text: async () => "<html><body></body></html>",
-            };
-        });
+        globalThis.fetch = jest.fn(recordAndAnswer);
     });
 
     afterEach(() => {
         globalThis.fetch = realFetch;
+        delete globalThis.chrome;
     });
 
+    // Storage holds `profile` as the stored profile, or nothing when it is
+    // undefined.
+    function storing(profile) {
+        globalThis.chrome = {
+            storage: makeStorageStub(
+                profile === undefined ? {} : { autistmask: profile },
+            ),
+        };
+    }
+
     test("Blockscout's token balances are asked for only while Use Blockscout is on", async () => {
-        expect(
-            await fetchTokenBalances(ADDRESS, BLOCKSCOUT, false, []),
-        ).toEqual([]);
+        storing({ useBlockscout: false });
+        expect(await fetchTokenBalances(ADDRESS, BLOCKSCOUT, [])).toEqual([]);
         expect(asked).toEqual([]);
 
-        const rows = await fetchTokenBalances(ADDRESS, BLOCKSCOUT, true, []);
+        storing({ useBlockscout: true });
+        const rows = await fetchTokenBalances(ADDRESS, BLOCKSCOUT, []);
         expect(rows.map((row) => row.symbol)).toEqual(["USDC"]);
         expect(asked).toEqual([
             BLOCKSCOUT + "/addresses/" + ADDRESS + "/token-balances",
@@ -125,12 +168,14 @@ describe("where each request is made", () => {
     });
 
     test("the transaction history is asked for only while Use Blockscout is on", async () => {
+        storing({ useBlockscout: false });
         expect(
-            await fetchRecentTransactions(ADDRESS, BLOCKSCOUT, false, "0x1"),
+            await fetchRecentTransactions(ADDRESS, BLOCKSCOUT, "0x1"),
         ).toEqual([]);
         expect(asked).toEqual([]);
 
-        await fetchRecentTransactions(ADDRESS, BLOCKSCOUT, true, "0x1");
+        storing({ useBlockscout: true });
+        await fetchRecentTransactions(ADDRESS, BLOCKSCOUT, "0x1");
         expect(asked.sort()).toEqual([
             BLOCKSCOUT +
                 "/addresses/" +
@@ -146,26 +191,78 @@ describe("where each request is made", () => {
             getTransactionCount: async () => 1,
             getBalance: async () => 0n,
         };
-        const checkWith = async (stored) => {
-            globalThis.chrome = { storage: makeStorageStub(stored) };
-            try {
-                await getFullWarnings(RECIPIENT, provider, { chainId: "0x1" });
-            } finally {
-                delete globalThis.chrome;
-            }
+        const checkWith = async (profile) => {
+            storing(profile);
+            await getFullWarnings(RECIPIENT, provider, { chainId: "0x1" });
         };
 
-        await checkWith({});
-        await checkWith({ autistmask: { checkRecipientsOnEtherscan: false } });
+        await checkWith(undefined);
+        await checkWith({ checkRecipientsOnEtherscan: false });
         // Only a stored true is on, as when the profile is loaded.
-        await checkWith({ autistmask: { checkRecipientsOnEtherscan: "true" } });
-        await checkWith({ autistmask: { checkRecipientsOnEtherscan: 42 } });
+        await checkWith({ checkRecipientsOnEtherscan: "true" });
+        await checkWith({ checkRecipientsOnEtherscan: 42 });
         expect(asked).toEqual([]);
 
-        await checkWith({ autistmask: { checkRecipientsOnEtherscan: true } });
+        await checkWith({ checkRecipientsOnEtherscan: true });
         expect(asked).toEqual(["https://etherscan.io/address/" + RECIPIENT]);
     });
 
+    // Asks with `setting` on in storage. Once every request is out, storage
+    // holds `after` for it, as when the user changes it here or on another
+    // page. Only then does each request get its answer.
+    async function answeredAfter(setting, after, ask) {
+        storing({ [setting]: true });
+        let release;
+        const held = new Promise((resolve) => {
+            release = resolve;
+        });
+        let requested;
+        const out = new Promise((resolve) => {
+            requested = resolve;
+        });
+        globalThis.fetch = jest.fn(async (url) => {
+            requested();
+            await held;
+            return recordAndAnswer(url);
+        });
+        const result = ask();
+        await out;
+        globalThis.chrome.storage.write("autistmask", { [setting]: after });
+        release();
+        return result;
+    }
+
+    // Each request, the setting that gates it, how to make it, and its answer
+    // while that setting is off.
+    test.each([
+        [
+            "Blockscout's token balances",
+            "useBlockscout",
+            () => fetchTokenBalances(ADDRESS, BLOCKSCOUT, []),
+            [],
+        ],
+        [
+            "the transaction history",
+            "useBlockscout",
+            () => fetchRecentTransactions(ADDRESS, BLOCKSCOUT, "0x1"),
+            [],
+        ],
+        [
+            "the Etherscan label check",
+            "checkRecipientsOnEtherscan",
+            () => checkEtherscanLabel(RECIPIENT, "0x1"),
+            null,
+        ],
+    ])(
+        "%s keeps an answer that lands while its setting is on, and drops one that lands after it went off",
+        async (_what, setting, ask, dropped) => {
+            expect(await answeredAfter(setting, true, ask)).not.toEqual(
+                dropped,
+            );
+            expect(await answeredAfter(setting, false, ask)).toEqual(dropped);
+        },
+    );
+
     describe("a balance refresh", () => {
         // The RPC endpoint answers every balance with zero, and every other
         // call, the ENS reverse lookup's, with no resolver.
@@ -212,11 +309,11 @@ describe("where each request is made", () => {
         }
 
         async function refresh(addr, useBlockscout) {
+            storing({ useBlockscout });
             await refreshBalances(
                 [{ addresses: [addr] }],
                 RPC_URL,
                 BLOCKSCOUT,
-                useBlockscout,
                 [],
                 "mainnet",
             );
@@ -258,29 +355,6 @@ describe("the popup", () => {
         jest.spyOn(console, "error").mockImplementation(() => {});
     });
 
-    test("hands its balance refresh and Home's history the stored Use Blockscout setting", async () => {
-        await bootPopup(unversionedValidProfile());
-        const {
-            refreshBalances: popupRefresh,
-        } = require("../src/shared/balances");
-        const {
-            fetchRecentTransactions: popupHistory,
-        } = require("../src/shared/transactions");
-        expect(popupRefresh.mock.calls[0][3]).toBe(false);
-        expect(popupHistory.mock.calls[0][2]).toBe(false);
-        cleanupPopup();
-
-        await bootPopup(unversionedValidProfile({ useBlockscout: true }));
-        const {
-            refreshBalances: onRefresh,
-        } = require("../src/shared/balances");
-        const {
-            fetchRecentTransactions: onHistory,
-        } = require("../src/shared/transactions");
-        expect(onRefresh.mock.calls[0][3]).toBe(true);
-        expect(onHistory.mock.calls[0][2]).toBe(true);
-    });
-
     test("Home says why there is no history and only tracked tokens while Use Blockscout is off", async () => {
         const page = await bootPopup(unversionedValidProfile());
         expect(page.node("home-tx-list").innerHTML).toContain(
@@ -341,6 +415,51 @@ describe("the popup", () => {
         expect(on.hidden("tx-detail-blockscout-note")).toBe(true);
     });
 
+    // Another page turns "Use Blockscout" off while TransactionDetail's request
+    // to Blockscout is out. This page draws TransactionDetail again with its
+    // line, and only then does Blockscout answer.
+    test("TransactionDetail shows nothing from an answer that lands after another page turned Use Blockscout off", async () => {
+        const page = await bootPopup(
+            onTransactionScreen({ useBlockscout: true }),
+        );
+        let release;
+        const held = new Promise((resolve) => {
+            release = resolve;
+        });
+        globalThis.fetch = jest.fn(async () => {
+            await held;
+            return {
+                ok: true,
+                status: 200,
+                json: async () => ({
+                    block_number: 21000000,
+                    fee: { value: "21000000000000" },
+                    raw_input: "0x12345678",
+                    method: "doSomething",
+                }),
+            };
+        });
+        require("../src/popup/views/transactionDetail").render();
+        await page.settle();
+        expect(fetched()).toEqual([BLOCKSCOUT + "/transactions/" + TX_HASH]);
+
+        await anotherPageAnnounces(page, { useBlockscout: false });
+        release();
+        await page.settle();
+
+        expect(page.visibleViews()).toEqual(["transaction"]);
+        expect(page.hidden("tx-detail-blockscout-note")).toBe(false);
+        for (const id of [
+            "tx-detail-block-section",
+            "tx-detail-network-section",
+            "tx-detail-calldata-section",
+            "tx-detail-rawdata-section",
+        ]) {
+            expect(page.hidden(id)).toBe(true);
+        }
+        expect(fetched()).toHaveLength(1);
+    });
+
     // The confirmation screen for a send of 0.1 ETH to RECIPIENT, as a
     // reopened popup draws it.
     function onConfirmScreen(extra) {
@@ -628,24 +747,22 @@ describe("the popup", () => {
         ["off", true, false],
         ["on", false, true],
     ])(
-        "after another page turns Use Blockscout %s, this page's next refresh follows the stored setting and is saved",
+        "after another page turns Use Blockscout %s, this page takes the change and its next refresh is saved",
         async (_how, before, after) => {
             const page = await bootPopup(onAddressDetail(before));
+            // The refresh answers as it does under the stored setting.
             const { refreshBalances: held } = require("../src/shared/balances");
-            held.mockImplementationOnce(
-                async (wallets, rpcUrl, blockscoutUrl, useBlockscout) => {
-                    const addr = wallets[0].addresses[0];
-                    addr.balance = "7.0";
-                    addr.tokenBalances = useBlockscout
-                        ? [tokenRow(TRACKED, "TRK"), tokenRow(UNTRACKED, "TST")]
-                        : [tokenRow(TRACKED, "TRK")];
-                },
-            );
+            held.mockImplementationOnce(async (wallets) => {
+                const addr = wallets[0].addresses[0];
+                addr.balance = "7.0";
+                addr.tokenBalances = after
+                    ? [tokenRow(TRACKED, "TRK"), tokenRow(UNTRACKED, "TST")]
+                    : [tokenRow(TRACKED, "TRK")];
+            });
 
             anotherPageSaves(page, { useBlockscout: after });
             await page.tick();
 
-            expect(held.mock.calls.at(-1)[3]).toBe(after);
             expect(
                 page.storage.read("autistmask").wallets[0].addresses[0].balance,
             ).toBe("7.0");
@@ -722,65 +839,3 @@ describe("the popup", () => {
         expect(page.hidden("confirm-etherscan-note")).toBe(false);
     });
 });
-
-describe("the background", () => {
-    afterEach(() => {
-        delete globalThis.chrome;
-        jest.dontMock("../src/shared/balances");
-    });
-
-    // Starts the background over `profile`, fires its balance alarm, and
-    // answers with the Use Blockscout setting its refresh was handed.
-    async function settingTheRefreshIsHanded(profile) {
-        jest.resetModules();
-        let handed;
-        const called = new Promise((resolve) => {
-            handed = resolve;
-        });
-        jest.doMock("../src/shared/balances", () => ({
-            getProvider: () => ({}),
-            refreshBalances: async (...args) => handed(args[3]),
-            dropUntrackedTokens: () => {},
-        }));
-        let onAlarm = null;
-        globalThis.chrome = {
-            storage: makeStorageStub({ autistmask: profile }),
-            alarms: {
-                create: () => {},
-                get: async () => undefined,
-                clear: async () => false,
-                onAlarm: {
-                    addListener: (fn) => {
-                        onAlarm = fn;
-                    },
-                },
-            },
-            runtime: {
-                onMessage: { addListener: () => {} },
-                onConnect: { addListener: () => {} },
-                onInstalled: { addListener: () => {} },
-                onStartup: { addListener: () => {} },
-                getURL: (p) => "chrome-extension://test/" + p,
-                lastError: null,
-            },
-            windows: { onRemoved: { addListener: () => {} } },
-            tabs: { query: () => {}, sendMessage: () => {} },
-            action: { setPopup: () => {} },
-        };
-        require("../src/background/index");
-        const { BALANCE_REFRESH_ALARM } = require("../src/shared/alarms");
-        onAlarm({ name: BALANCE_REFRESH_ALARM });
-        return called;
-    }
-
-    test("hands its balance refresh the stored Use Blockscout setting", async () => {
-        const profile = { ...unversionedValidProfile(), lastBalanceRefresh: 0 };
-        expect(await settingTheRefreshIsHanded(profile)).toBe(false);
-        expect(
-            await settingTheRefreshIsHanded({
-                ...profile,
-                useBlockscout: true,
-            }),
-        ).toBe(true);
-    });
-});

tests/confirmTxAmount.test.js

@@ -108,7 +108,10 @@ global.fetch = jest.fn(() => {
 });
 
 const { makeStorageStub } = require("./support/storageStub");
-global.chrome = { storage: makeStorageStub(), runtime: { sendMessage() {} } };
+global.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+    runtime: { sendMessage() {} },
+};
 
 // A stub DOM: every id resolves to a recording element.
 const elements = new Map();
@@ -243,11 +246,13 @@ async function openSend(token, tokenUnits = null) {
     ];
     state.selectedWallet = 0;
     state.selectedAddress = 0;
+    // Blockscout is asked only while the stored "Use Blockscout" is on. The
+    // screens save this page's copy of it over the stored one.
+    state.useBlockscout = true;
     await refreshBalances(
         state.wallets,
         "https://rpc.example.invalid",
         "https://blockscout.example/api/v2",
-        true,
         state.trackedTokens,
         "mainnet",
     );

tests/fabricatedDecimals.test.js

@@ -35,8 +35,11 @@ global.fetch = jest.fn(() => {
     throw new Error("tests must not perform network requests");
 });
 
+// Blockscout is asked only while the stored "Use Blockscout" is on.
 const { makeStorageStub } = require("./support/storageStub");
-global.chrome = { storage: makeStorageStub() };
+global.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+};
 
 const { AbiCoder, Interface } = require("ethers");
 const { ERC20_ABI } = require("../src/shared/constants");
@@ -114,7 +117,6 @@ async function fetchOnto(items, trackedTokens = []) {
     const balances = await fetchTokenBalances(
         HOLDER,
         BLOCKSCOUT,
-        true,
         trackedTokens,
     );
     state.trackedTokens = trackedTokens;

tests/holders.test.js

@@ -21,7 +21,11 @@ jest.mock("../src/shared/log", () => ({
 global.fetch = jest.fn(() => {
     throw new Error("tests must not perform network requests");
 });
-global.chrome = { storage: { local: {} } };
+// Blockscout is asked only while the stored "Use Blockscout" is on.
+const { makeStorageStub } = require("./support/storageStub");
+global.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+};
 
 const {
     LOW_HOLDER_THRESHOLD,
@@ -150,23 +154,19 @@ describe("the balance-list spam gate", () => {
 
     test("a token with plenty of reported holders is listed", async () => {
         respondWith([item()]);
-        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, []);
+        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
         expect(balances).toHaveLength(1);
         expect(balances[0].holders).toBe(50000);
     });
 
     test("a token reporting zero holders is still excluded", async () => {
         respondWith([item({ token: { holders_count: "0" } })]);
-        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, [])).toEqual(
-            [],
-        );
+        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, [])).toEqual([]);
     });
 
     test("an unknown holder count does not admit an unvouched token", async () => {
         respondWith([item({ token: { holders_count: null } })]);
-        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, [])).toEqual(
-            [],
-        );
+        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, [])).toEqual([]);
     });
 
     // The path that reaches the send selector and the history filter: a token
@@ -175,7 +175,7 @@ describe("the balance-list spam gate", () => {
     // zero that would then hide it downstream.
     test("a tracked token with an unknown count is listed with holders null", async () => {
         respondWith([item({ token: { holders_count: undefined } })]);
-        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, [
+        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, [
             { address: NOVEL_TOKEN.toUpperCase() },
         ]);
         expect(balances).toHaveLength(1);
@@ -192,7 +192,7 @@ describe("the balance-list spam gate", () => {
                 },
             }),
         ]);
-        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, []);
+        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
         expect(balances).toHaveLength(1);
         expect(balances[0].holders).toBeNull();
     });

tests/nativeCurrency.test.js

@@ -436,8 +436,13 @@ describe.each([
         });
 
         test("the transaction detail screen's type line and fee", async () => {
-            // The fee is Blockscout's.
+            // The fee is Blockscout's, asked for only while the stored "Use
+            // Blockscout" is on.
             state.useBlockscout = true;
+            global.chrome.storage.write("autistmask", {
+                ...global.chrome.storage.read("autistmask"),
+                useBlockscout: true,
+            });
             debugFetch.mockImplementationOnce(async () => ({
                 ok: true,
                 status: 200,

tests/popupFollowsNetworkSwitch.test.js

@@ -87,7 +87,7 @@ test("the popup open on AddressDetail shows the new network and its balances", a
     // Its next refresh runs on Sepolia, and what it fetched is stored.
     await page.tick();
     const { refreshBalances } = require("../src/shared/balances");
-    expect(refreshBalances.mock.lastCall[5]).toBe("sepolia");
+    expect(refreshBalances.mock.lastCall[4]).toBe("sepolia");
     const stored = page.storage.read("autistmask");
     expect(stored.networkId).toBe("sepolia");
     expect(stored.lastBalanceRefresh).toBeGreaterThan(0);

tests/rpcErrorLog.test.js

@@ -88,7 +88,6 @@ test("the balance refresh", async () => {
         wallets,
         RPC_URL,
         "https://explorer.example.invalid/api/v2",
-        true,
         [],
         "mainnet",
     );

tests/sendDisplayFloor.test.js

@@ -90,7 +90,7 @@ let approvalDetails = null;
 
 const { makeStorageStub } = require("./support/storageStub");
 global.chrome = {
-    storage: makeStorageStub(),
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
     runtime: {
         connect: () => ({
             postMessage() {},
@@ -220,11 +220,13 @@ async function refreshWith(balanceWei, tokenItems = []) {
     state.wallets = [{ name: "Wallet 1", addresses: [{ address: HOLDER }] }];
     state.selectedWallet = 0;
     state.selectedAddress = 0;
+    // Blockscout is asked only while the stored "Use Blockscout" is on. The
+    // screens save this page's copy of it over the stored one.
+    state.useBlockscout = true;
     await refreshBalances(
         state.wallets,
         "https://rpc.example.invalid",
         "https://blockscout.example/api/v2",
-        true,
         state.trackedTokens,
         "mainnet",
     );

tests/sendMax.test.js

@@ -100,7 +100,10 @@ global.fetch = jest.fn(() => {
 });
 
 const { makeStorageStub } = require("./support/storageStub");
-global.chrome = { storage: makeStorageStub(), runtime: { sendMessage() {} } };
+global.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+    runtime: { sendMessage() {} },
+};
 
 // A stub DOM: every id resolves to a recording element.
 const elements = new Map();
@@ -213,11 +216,13 @@ async function refreshWith(balanceWei, tokenItems = []) {
     ];
     state.selectedWallet = 0;
     state.selectedAddress = 0;
+    // Blockscout is asked only while the stored "Use Blockscout" is on. The
+    // screens save this page's copy of it over the stored one.
+    state.useBlockscout = true;
     await refreshBalances(
         state.wallets,
         "https://rpc.example.invalid",
         "https://blockscout.example/api/v2",
-        true,
         state.trackedTokens,
         "mainnet",
     );

tests/symbolSpoof.test.js

@@ -52,8 +52,14 @@ jest.mock("../src/shared/log", () => ({
 global.fetch = jest.fn(() => {
     throw new Error("tests must not perform network requests");
 });
+// Blockscout is asked only while the stored "Use Blockscout" is on.
 global.chrome = {
-    storage: { local: { get: async () => ({}), set: async () => {} } },
+    storage: {
+        local: {
+            get: async () => ({ autistmask: { useBlockscout: true } }),
+            set: async () => {},
+        },
+    },
 };
 
 const { isSpoofedSymbol } = require("../src/shared/symbolSpoof");
@@ -586,14 +592,12 @@ describe("surface 3: the balance list", () => {
     // 1,000-holder floor and was listed as a holding named ETH.
     test("a fake ETH token clearing the holder floor is filtered", async () => {
         respondWith([fakeEthItem()]);
-        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, [])).toEqual(
-            [],
-        );
+        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, [])).toEqual([]);
     });
 
     test("tracking the fake token manually does not admit it either", async () => {
         respondWith([fakeEthItem({ holders_count: "0" })]);
-        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, [
+        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, [
             { address: FAKE_ETH_CONTRACT },
         ]);
         expect(balances).toEqual([]);
@@ -603,16 +607,12 @@ describe("surface 3: the balance list", () => {
     // their belief about what they own, and it renders the symbol into HTML.
     test("a padded fake ETH token is filtered too", async () => {
         respondWith([fakeEthItem({ symbol: " ETH " })]);
-        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, [])).toEqual(
-            [],
-        );
+        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, [])).toEqual([]);
     });
 
     test("a fake ETH token padded with a no-break space is filtered", async () => {
         respondWith([fakeEthItem({ symbol: NBSP + "ETH" + NBSP })]);
-        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, [])).toEqual(
-            [],
-        );
+        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, [])).toEqual([]);
     });
 
     // The false-positive direction on the surface that matters most: a real
@@ -627,7 +627,7 @@ describe("surface 3: the balance list", () => {
                 decimals: "6",
             }),
         ]);
-        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, []);
+        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
         expect(balances).toHaveLength(1);
         expect(balances[0].symbol).toBe(" USDC ");
     });
@@ -641,7 +641,7 @@ describe("surface 3: the balance list", () => {
                 decimals: "6",
             }),
         ]);
-        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, []);
+        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
         expect(balances).toHaveLength(1);
         expect(balances[0].symbol).toBe("USDC");
     });
@@ -652,9 +652,7 @@ describe("surface 3: the balance list", () => {
     // before the symbol rule is consulted.
     test("a non-ERC-20 row claiming ETH never reaches the symbol rule", async () => {
         respondWith([fakeEthItem({ type: "ERC-721" })]);
-        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, [])).toEqual(
-            [],
-        );
+        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, [])).toEqual([]);
     });
 
     // The adjacent finding from the same review as issue #260: the type gate
@@ -672,20 +670,16 @@ describe("surface 3: the balance list", () => {
                 decimals: "6",
             }),
         ]);
-        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, []);
+        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
         expect(balances).toHaveLength(1);
         expect(balances[0].symbol).toBe("USDC");
     });
 
     test("case insensitivity does not admit another token type", async () => {
         respondWith([fakeEthItem({ type: "erc-721" })]);
-        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, [])).toEqual(
-            [],
-        );
+        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, [])).toEqual([]);
         respondWith([fakeEthItem({ type: "ERC-20-EXTRA" })]);
-        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, [])).toEqual(
-            [],
-        );
+        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, [])).toEqual([]);
     });
 
     // The money test: the user holds real ETH and has been airdropped a fake
@@ -698,7 +692,6 @@ describe("surface 3: the balance list", () => {
             [{ addresses: [addr] }],
             "https://rpc.example.invalid",
             BLOCKSCOUT,
-            true,
             [],
             "mainnet",
         );

tests/tokenTransferDetail.test.js

@@ -38,8 +38,14 @@ jest.mock("../src/shared/log", () => ({
     isDebug: () => false,
 }));
 
+// Blockscout is asked only while the stored "Use Blockscout" is on.
 globalThis.chrome = {
-    storage: { local: { get: async () => ({}), set: async () => {} } },
+    storage: {
+        local: {
+            get: async () => ({ autistmask: { useBlockscout: true } }),
+            set: async () => {},
+        },
+    },
 };
 
 const { state } = require("../src/shared/state");
@@ -178,7 +184,6 @@ test("a token transfer's decoded details name the token contract and the amount
     const [row] = await fetchRecentTransactions(
         HOLDER,
         EXPLORER,
-        true,
         NETWORKS.mainnet.chainId,
     );
     expect(row.to).toBe(RECIPIENT);
@@ -211,7 +216,6 @@ test("with mainnet active, a Sepolia transaction is read from Sepolia's Blocksco
     const [row] = await fetchRecentTransactions(
         HOLDER,
         EXPLORER,
-        true,
         NETWORKS.sepolia.chainId,
     );
 
@@ -240,7 +244,6 @@ test("with mainnet active and no Blockscout remembered for Sepolia, a Sepolia tr
     const [row] = await fetchRecentTransactions(
         HOLDER,
         EXPLORER,
-        true,
         NETWORKS.sepolia.chainId,
     );
     mockAsked.length = 0;
@@ -262,7 +265,6 @@ async function showSepoliaTransferWithMainnetActive() {
     const [row] = await fetchRecentTransactions(
         HOLDER,
         EXPLORER,
-        true,
         NETWORKS.sepolia.chainId,
     );
     transactionDetail.show(row);

tests/trackedTokenBalances.test.js

@@ -9,6 +9,12 @@
 
 const { AbiCoder, FetchRequest } = require("ethers");
 const { refreshBalances } = require("../src/shared/balances");
+const { makeStorageStub } = require("./support/storageStub");
+
+// Blockscout is asked only while the stored "Use Blockscout" is on.
+globalThis.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+};
 
 const RPC_URL = "https://rpc.example.invalid";
 const EXPLORER_URL = "https://explorer.example.invalid/api/v2";
@@ -132,7 +138,6 @@ async function refresh(addresses, trackedTokens) {
         [{ addresses }],
         RPC_URL,
         EXPLORER_URL,
-        true,
         trackedTokens,
         "mainnet",
         new AbortController().signal,

tests/transactions.test.js

@@ -1215,11 +1215,13 @@ function respondWith(txItems, tokenTransferItems) {
 describe("fetchRecentTransactions merge and dedup", () => {
     beforeEach(() => {
         debugFetch.mockReset();
+        // Blockscout is asked only while the stored "Use Blockscout" is on.
+        global.chrome.storage.write("autistmask", { useBlockscout: true });
     });
 
     test("queries only the two Blockscout endpoints for the address", async () => {
         respondWith([], []);
-        await fetchRecentTransactions(VICTIM, BLOCKSCOUT, true, "0x1");
+        await fetchRecentTransactions(VICTIM, BLOCKSCOUT, "0x1");
         expect(debugFetch).toHaveBeenCalledTimes(2);
         const urls = debugFetch.mock.calls.map((c) => c[0]);
         expect(urls).toContain(
@@ -1283,12 +1285,7 @@ describe("fetchRecentTransactions merge and dedup", () => {
             ],
         );
 
-        const txs = await fetchRecentTransactions(
-            VICTIM,
-            BLOCKSCOUT,
-            true,
-            "0x1",
-        );
+        const txs = await fetchRecentTransactions(VICTIM, BLOCKSCOUT, "0x1");
         expect(txs).toHaveLength(1);
         const merged = txs[0];
         // The received leg (the swap output) supplies the display amount.
@@ -1325,12 +1322,7 @@ describe("fetchRecentTransactions merge and dedup", () => {
             ],
         );
 
-        const txs = await fetchRecentTransactions(
-            VICTIM,
-            BLOCKSCOUT,
-            true,
-            "0x1",
-        );
+        const txs = await fetchRecentTransactions(VICTIM, BLOCKSCOUT, "0x1");
         expect(txs).toHaveLength(1);
         expect(txs[0].symbol).toBe("USDC");
         expect(txs[0].value).toBe("1500.5000");
@@ -1356,12 +1348,7 @@ describe("fetchRecentTransactions merge and dedup", () => {
         });
         respondWith([], [leg("1000000"), leg("2000000")]);
 
-        const txs = await fetchRecentTransactions(
-            VICTIM,
-            BLOCKSCOUT,
-            true,
-            "0x1",
-        );
+        const txs = await fetchRecentTransactions(VICTIM, BLOCKSCOUT, "0x1");
         expect(txs).toHaveLength(1);
         // Keyed by hash plus contract, so the later leg wins.
         expect(txs[0].exactValue).toBe("2.0");
@@ -1401,12 +1388,7 @@ describe("fetchRecentTransactions merge and dedup", () => {
             ],
         );
 
-        const txs = await fetchRecentTransactions(
-            VICTIM,
-            BLOCKSCOUT,
-            true,
-            "0x1",
-        );
+        const txs = await fetchRecentTransactions(VICTIM, BLOCKSCOUT, "0x1");
         expect(txs.map((t) => t.symbol).sort()).toEqual(["USDC", "WETH"]);
     });
 
@@ -1447,12 +1429,7 @@ describe("fetchRecentTransactions merge and dedup", () => {
             ],
         );
 
-        const txs = await fetchRecentTransactions(
-            VICTIM,
-            BLOCKSCOUT,
-            true,
-            "0x1",
-        );
+        const txs = await fetchRecentTransactions(VICTIM, BLOCKSCOUT, "0x1");
         expect(txs).toHaveLength(1);
         expect(txs[0].symbol).toBe("USDC");
         expect(txs[0].exactValue).toBe("1.0");
@@ -1478,13 +1455,7 @@ describe("fetchRecentTransactions merge and dedup", () => {
         });
         respondWith([item(6), item(8), item(7)], []);
 
-        const txs = await fetchRecentTransactions(
-            VICTIM,
-            BLOCKSCOUT,
-            true,
-            "0x1",
-            2,
-        );
+        const txs = await fetchRecentTransactions(VICTIM, BLOCKSCOUT, "0x1", 2);
         expect(txs.map((t) => t.blockNumber)).toEqual([21000008, 21000007]);
     });
 
@@ -1510,7 +1481,6 @@ describe("fetchRecentTransactions merge and dedup", () => {
         const sepolia = await fetchRecentTransactions(
             VICTIM,
             BLOCKSCOUT,
-            true,
             "0xaa36a7",
         );
         expect(sepolia[0].symbol).toBe("SepoliaETH");
@@ -1519,7 +1489,6 @@ describe("fetchRecentTransactions merge and dedup", () => {
         const mainnet = await fetchRecentTransactions(
             VICTIM,
             BLOCKSCOUT,
-            true,
             "0x1",
         );
         expect(mainnet[0].symbol).toBe("ETH");
@@ -1546,12 +1515,7 @@ describe("fetchRecentTransactions merge and dedup", () => {
             ],
         );
 
-        const txs = await fetchRecentTransactions(
-            VICTIM,
-            BLOCKSCOUT,
-            true,
-            "0x1",
-        );
+        const txs = await fetchRecentTransactions(VICTIM, BLOCKSCOUT, "0x1");
         expect(txs).toHaveLength(1);
         expect(txs[0].contractAddress).toBe(FAKE_ETH_CONTRACT);
         expect(txs[0].holders).toBe(0);
@@ -1593,7 +1557,6 @@ describe("fetchRecentTransactions merge and dedup", () => {
             const txs = await fetchRecentTransactions(
                 VICTIM,
                 BLOCKSCOUT,
-                true,
                 "0x1",
             );
             expect(txs[0].holders).toBeNull();
@@ -1604,7 +1567,6 @@ describe("fetchRecentTransactions merge and dedup", () => {
             const txs = await fetchRecentTransactions(
                 VICTIM,
                 BLOCKSCOUT,
-                true,
                 "0x1",
             );
             expect(txs[0].holders).toBeNull();
@@ -1615,7 +1577,6 @@ describe("fetchRecentTransactions merge and dedup", () => {
             const txs = await fetchRecentTransactions(
                 VICTIM,
                 BLOCKSCOUT,
-                true,
                 "0x1",
             );
             expect(filterTransactions(txs, filters()).transactions).toEqual(
@@ -1632,7 +1593,6 @@ describe("fetchRecentTransactions merge and dedup", () => {
             const txs = await fetchRecentTransactions(
                 VICTIM,
                 BLOCKSCOUT,
-                true,
                 "0x1",
             );
             expect(txs[0].holders).toBe(0);
@@ -1650,7 +1610,7 @@ describe("fetchRecentTransactions merge and dedup", () => {
             },
         }));
         await expect(
-            fetchRecentTransactions(VICTIM, BLOCKSCOUT, true, "0x1"),
+            fetchRecentTransactions(VICTIM, BLOCKSCOUT, "0x1"),
         ).resolves.toEqual([]);
     });
 

tests/uniswapRecipient.test.js

@@ -42,8 +42,14 @@ jest.mock("../src/shared/log", () => ({
     isDebug: () => false,
 }));
 
+// Blockscout is asked only while the stored "Use Blockscout" is on.
 globalThis.chrome = {
-    storage: { local: { get: async () => ({}), set: async () => {} } },
+    storage: {
+        local: {
+            get: async () => ({ autistmask: { useBlockscout: true } }),
+            set: async () => {},
+        },
+    },
 };
 
 const uniswap = require("../src/shared/uniswap");

tests/uniswapRouterAddress.test.js

@@ -34,8 +34,14 @@ jest.mock("../src/shared/log", () => ({
     isDebug: () => false,
 }));
 
+// Blockscout is asked only while the stored "Use Blockscout" is on.
 globalThis.chrome = {
-    storage: { local: { get: async () => ({}), set: async () => {} } },
+    storage: {
+        local: {
+            get: async () => ({ autistmask: { useBlockscout: true } }),
+            set: async () => {},
+        },
+    },
 };
 
 const { state } = require("../src/shared/state");
@@ -288,7 +294,6 @@ async function historyRow(method, sentTo, chainId) {
     const rows = await fetchRecentTransactions(
         RECIPIENT,
         "https://explorer.example/api/v2",
-        true,
         chainId,
     );
     return rows[0];

tests/unknownScaleSend.test.js

@@ -72,8 +72,12 @@ global.fetch = jest.fn(() => {
     throw new Error("tests must not perform network requests");
 });
 
+// Blockscout is asked only while the stored "Use Blockscout" is on.
 const { makeStorageStub } = require("./support/storageStub");
-global.chrome = { storage: makeStorageStub(), runtime: { sendMessage() {} } };
+global.chrome = {
+    storage: makeStorageStub({ autistmask: { useBlockscout: true } }),
+    runtime: { sendMessage() {} },
+};
 
 // A stub DOM. Every id in index.html that these two views touch resolves to a
 // fresh recording element; nothing here depends on layout, only on what the
@@ -172,7 +176,7 @@ async function fetchOnto(items) {
         statusText: "OK",
         json: async () => items,
     }));
-    const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, []);
+    const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
     state.wallets = [
         {
             name: "Wallet 1",
@@ -197,14 +201,14 @@ async function fetchOntoBoth(itemsA, itemsB) {
         statusText: "OK",
         json: async () => itemsA,
     }));
-    const a = await fetchTokenBalances(HOLDER, BLOCKSCOUT, true, []);
+    const a = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
     debugFetch.mockImplementation(async () => ({
         ok: true,
         status: 200,
         statusText: "OK",
         json: async () => itemsB,
     }));
-    const b = await fetchTokenBalances(SECOND_HOLDER, BLOCKSCOUT, true, []);
+    const b = await fetchTokenBalances(SECOND_HOLDER, BLOCKSCOUT, []);
     state.wallets = [
         {
             name: "Wallet 1",
@@ -268,6 +272,9 @@ beforeEach(() => {
     state.fraudContracts = [];
     state.hideLowHolderTokens = false;
     state.currentView = null;
+    // The screens save this page's copy of "Use Blockscout" over the stored
+    // one, so it is on here too.
+    state.useBlockscout = true;
 });
 
 describe("the Send screen resolves the scale rather than reading the stored one", () => {