fix: one transaction approval at a time, and honest copy for a nonce collision (closes #271)

Populating the transaction in the background before the approval window
opens is what makes the displayed object the verified object. It also
fixes the nonce before the user has answered anything, so two
eth_sendTransaction calls populated concurrently took the same nonce
from a node that had seen neither of them broadcast, and the second
could never be sent: its approved nonce is spent, and the only way to
give it a fresh one is to populate it again after the user has read the
old one off the screen.

A second transaction approval is now refused while one is unanswered,
with EIP-1193 code -32002. The refusal happens before anything is
populated — no second nonce is allocated, no window opens — and the slot
is released when the requesting page has its answer. Signature approvals
are not gated; a signature consumes no nonce.

A collision that does happen is now reported for what it is. A broadcast
the node refused for the nonce, and an approval carrying a nonce this
worker has already broadcast (caught before the node is asked at all),
both report that the transaction did not reach the network and to send
it again, instead of the standing broadcast wording that warns it may
have sent. "already known" keeps that ambiguous wording deliberately: a
node that says it has the transaction has it.

Nothing about verification is weakened. The approval still carries the
transaction the screen displayed, and the artifact is still compared
against that object field for field.

README.md

@@ -169,6 +169,34 @@ reserve while sitting on the same side of the estimate, so swapping the two in
 what [#154](https://git.eeqj.de/sneak/AutistMask/issues/154) was, and it was
 previously correct by reading only.
 
+It also covers the **dApp approval round trips** — the one place where the
+content script, the inpage provider, the background worker and the approval
+popup all have to work together. A local test page is served by the route
+handler on a reserved-TLD origin, gets `window.ethereum` from the shipped
+`MAIN`-world content script like any other page, and drives
+`eth_requestAccounts`, `personal_sign`, `eth_signTypedData_v4` and
+`eth_sendTransaction` through the real prompts. Every signature is recovered in
+the runner and compared against the active address, the transaction assertions
+run against the raw signed transaction captured at `eth_sendRawTransaction`
+rather than against anything the extension reported, rejecting each prompt is
+required to return a rejection to the page rather than hang or resolve, and the
+password is required to be absent from every message the approval window sends
+to the background — with the message that would carry it required to be present,
+so that check cannot pass by observing nothing. That last one is the standing
+floor under [#157](https://git.eeqj.de/sneak/AutistMask/issues/157).
+
+Three limits of that coverage, none of them papered over. The RPC is stubbed
+throughout, so this is **not** a real dApp against a real network with real
+funds; that remains a human pass before 1.0.0. The site-connection prompt is
+raised through `chrome.action.openPopup()`, and headless Chromium's
+browser-action popup is not a page Playwright can see or click, so that one
+prompt is driven at the URL the extension itself puts on the action — the same
+page and the same approval id, but whether a real toolbar click shows it is not
+observable here. And the EIP-1193 error code does not survive the last hop: the
+rejection that crosses the boundary carries code 4001 and is asserted to, but
+`src/content/inpage.js` rebuilds it as `new Error(message)`, so the calling page
+catches an error with no `code` property.
+
 Any test that drives a failure path on purpose declares the `console.error` it
 is about to provoke, via `errors.expect()`. That is not a mute: the declaration
 consumes exactly one matching record, and a declaration nothing matched fails
@@ -610,15 +638,6 @@ ExportPrivKey and ShowRecoveryPhrase — are deliberately absent from that list,
 so the popup can never reopen onto one of them with no password prompt in front
 of it.
 
-A reopened popup renders the wallet list and the one screen it restores onto,
-and nothing else, so every screen on the stack behind that one is still the
-blank template from `index.html`. "Back" therefore renders its target rather
-than only unhiding it, through the same dispatch and data guards as the restore
-(`src/popup/viewRouter.js`), and falls back to Home when the state the target
-would render is gone. Forward navigation renders as it goes and does not go
-through that dispatch: rendering a screen a second time would re-fetch and
-clobber whatever it has in flight.
-
 Every screen that holds secret material in the page registers a cleanup with
 `onViewLeave()` (`src/popup/views/helpers.js`), which `showView()` runs on every
 exit from that screen rather than only on its "Back" button, so nothing secret
@@ -1144,7 +1163,11 @@ on ConfirmTx, DeleteWallet, ApproveTx and ApproveSign.
   opening the window, so the screen shows a complete transaction and the signed
   artifact can be compared with it field for field. A request that cannot be
   populated — unreachable node, reverting gas estimate — opens no window and is
-  failed back to the site.
+  failed back to the site. Only one transaction approval exists at a time:
+  populating fixes the nonce, so a second `eth_sendTransaction` arriving while
+  one is unanswered is refused with EIP-1193 code `-32002` rather than being
+  populated at the same nonce. It opens no window and takes no nonce, and the
+  site can send it again once the pending one is answered.
 - **Elements**:
     - "Transaction Request" heading
     - Phishing warning banner (shown when the hostname is on the phishing

TODO.md

@@ -45,19 +45,76 @@ undefined identifiers, which is how
 
 # Completed Steps
 
-- 2026-08-12: "Back" now renders the screen it lands on instead of only unhiding
+- 2026-08-14: One transaction approval at a time. Populating in the background
-  it. A reopened popup renders the wallet list and the one screen it restores
+  before the window opens is what makes the displayed object the verified
-  onto, so every screen further down the stack was still the blank template from
+  object, and it also fixes the nonce: two `eth_sendTransaction` calls populated
-  `index.html`, and Back walked straight onto it — an empty address, no
+  concurrently took the same nonce from a node that had seen neither broadcast,
-  balances, no QR code. The Back path now goes through the same per-view
+  and the second could then never be sent, because the only way to give it a
-  dispatch and data guards as the restore (`src/popup/viewRouter.js`, shared
+  fresh nonce is to populate it again after the user has read the old one off
-  with `restoreView()`), falling back to Home when the state the target would
+  the screen. A second request is now refused with EIP-1193 `-32002` while one
-  render is gone, and declining any view the popup does not render from
+  is unanswered — before anything is populated, so no second nonce is allocated
-  persisted state, which can only be on the stack from the current page load and
+  and no second window opens — and the slot is freed when the page has its
-  was rendered on the way in. Forward navigation is untouched, so nothing
+  answer. Signature approvals are not gated, consuming no nonce. A collision
-  renders twice. Covered by unit tests on the real `goBack()` and by two
+  that does happen is also reported accurately now: a broadcast the node refused
-  end-to-end cases against the real popup, both demonstrated failing on the
+  for the nonce, and an approval carrying a nonce this worker has already
-  unfixed build ([#268](https://git.eeqj.de/sneak/AutistMask/issues/268)).
+  broadcast (caught before the node is asked at all), both say the transaction
+  did not reach the network and to send it again, instead of warning that it may
+  have sent. `already known` deliberately keeps the ambiguous wording, because a
+  node that says it has the transaction has it
+  ([#271](https://git.eeqj.de/sneak/AutistMask/issues/271)).
+- 2026-08-12: EIP-1193 error codes now reach the page. `src/content/inpage.js`
+  rebuilt every failure as `new Error(error.message)`, so the code the
+  background produced and the content script relayed intact was dropped in the
+  last hop and a dApp checking `err.code === 4001` saw `undefined` — a wallet
+  the user deliberately declined was indistinguishable from one that broke. The
+  provider now rejects with a `ProviderRpcError` carrying `code` and, where the
+  boundary sent one, `data`, passed through verbatim rather than matched against
+  a list, so 4001, 4100 and 4902 all arrive and a future code needs no edit
+  here. An error the background sent with no code stays a plain `Error` with no
+  `code` property, and `message` is unchanged in every case. All four request
+  entry points (`request`, `enable`, `send`, `sendAsync`) are covered by
+  `tests/inpageErrors.test.js`, and the e2e probe that printed the missing code
+  now requires it on the page's Error as well as on the wire, for all four
+  rejected flows ([#274](https://git.eeqj.de/sneak/AutistMask/issues/274)).
+- 2026-08-12: `KNOWN_SYMBOLS` now maps a symbol to the set of contract addresses
+  that bear it, not to one of them. A ticker is not unique: seven of the 512
+  bundled tokens — `FRAX`, `REUSD`, `TON`, `EURE`, `MSUSD`, `MUSD` and `JPYC` —
+  share a symbol with another bundled entry at a different real contract, and
+  the table, built from the list first-wins, kept only the earlier one. The
+  other seven were judged spoofs of their own symbol at their own address and
+  hidden from the balance list, the history and the send selector, so a holder
+  could not spend them. Both contracts of each pair come from the same CoinGecko
+  fetch of 2026-02-27, so neither was stale and neither was dropped.
+  `isSpoofedSymbol()` asks set membership instead of equality, which does not
+  loosen the rule — a contract outside the set is still a spoof — and a test now
+  walks `TOKENS` asserting no bundled token is filtered at its own address,
+  which is the walk the suite lacked
+  ([#276](https://git.eeqj.de/sneak/AutistMask/issues/276)).
+- 2026-08-12: The dApp approval round trips are driven end to end in the
+  browser. A test page served by the harness speaks EIP-1193 to the real inpage
+  provider through the real content script, background worker and approval popup
+  for `eth_requestAccounts`, `personal_sign`, `eth_signTypedData_v4` and
+  `eth_sendTransaction`. Every signature is recovered and compared against the
+  active address, the transaction is checked against the bytes handed to the
+  stubbed RPC, each rejection must reach the page as a rejection, and the
+  password must appear in no message the approval window sends — the assertion
+  that gives [#157](https://git.eeqj.de/sneak/AutistMask/issues/157) a permanent
+  floor. This does not discharge a real dApp with real funds against mainnet
+  ([#183](https://git.eeqj.de/sneak/AutistMask/issues/183)).
+- 2026-08-12: The known-symbol spoof rule now judges the symbol a user actually
+  sees. `isSpoofedSymbol()` normalizes before the lookup — NFKC, then every
+  character that paints nothing removed (the format and default-ignorable
+  characters, plus U+007F), then trimmed — so `" ETH "`, a no-break space, a
+  zero-width space, a Hangul filler, a variation selector, a DELETE and a
+  fullwidth `ＥＴＨ` are all caught on the balance list, the history and the
+  send selector at once. Confusables that are distinct letters (Cyrillic `Е`),
+  bidi reordering and the visible C0/C1 controls — which measure 48.00px, a box,
+  in the pinned e2e Chromium where an invisible prefix measures 32.00px — stay
+  knowingly open and are asserted as open in the suite. No bundled symbol
+  contains whitespace or a non-ASCII character, so nothing legitimate is newly
+  filtered; the balance list's token-type gate also became case-insensitive,
+  which no longer drops a real holding if an explorer writes `erc-20`
+  ([#260](https://git.eeqj.de/sneak/AutistMask/issues/260)).
 - 2026-08-12: A containerized Firefox end-to-end harness
   (`make test-e2e-firefox`) drives the real popup in a real Firefox with the MV2
   build installed as a temporary add-on. Zero npm dependencies — a WebDriver

src/background/index.js

@@ -24,6 +24,7 @@ const {
     TX_STAGE_VERIFY,
     TX_STAGE_BROADCAST,
     TX_STAGE_INFLIGHT,
+    TX_STAGE_NONCE,
 } = require("../shared/approvalVerify");
 const { prepareApprovalTx } = require("../shared/approvalTx");
 const {
@@ -57,6 +58,81 @@ const connectedSites = {};
 // Pending approval requests: { id: { origin, hostname, resolve } }
 const pendingApprovals = {};
 
+// One transaction approval at a time, wallet-wide.
+//
+// The transaction a site asks for is populated before its approval window
+// opens, so that the object the user is shown is the object the signed
+// artifact is verified against. Populating fixes the nonce. Two requests
+// populated concurrently therefore take the SAME nonce — the node reports the
+// same pending count to both, neither having been broadcast — and whichever is
+// broadcast second is refused by the network for a nonce it can never be
+// re-signed at, because re-signing it would mean signing something other than
+// what was displayed.
+//
+// So the second request is refused while the first is unanswered. It is
+// refused before anything is populated, so no second nonce is allocated at
+// all, and while the page is still waiting with nothing on screen. The
+// alternatives were considered and rejected in
+// https://git.eeqj.de/sneak/AutistMask/issues/271: populating again at Confirm
+// puts a nonce on screen that is not the nonce that gets signed, and
+// allocating around in-flight approvals makes the wallet's own bookkeeping the
+// authority on a nonce the network has not accepted, which an abandoned
+// approval then leaves a hole in.
+//
+// Sign approvals are not gated: a signature consumes no nonce.
+let txApprovalSlotHeld = false;
+
+// EIP-1474 "resource unavailable": the standard code for a request that is
+// refused because another one is already pending.
+const TX_APPROVAL_PENDING_CODE = -32002;
+
+const TX_APPROVAL_PENDING_MESSAGE =
+    "Another transaction is already waiting to be approved in AutistMask," +
+    " so this one was not sent. Please answer that request, then send this" +
+    " one again.";
+
+// Take the slot, or refuse. Called before the first await of the
+// eth_sendTransaction handler, so two requests arriving in the same tick
+// cannot both pass it.
+function reserveTxApprovalSlot() {
+    if (txApprovalSlotHeld) return false;
+    txApprovalSlotHeld = true;
+    return true;
+}
+
+function releaseTxApprovalSlot() {
+    txApprovalSlotHeld = false;
+}
+
+// Nonces this worker has already handed to the node, per address. This is the
+// wallet's own knowledge that a nonce is spent, and it is checked before a
+// broadcast rather than after: a node's pending count can lag a transaction it
+// has itself just accepted, and a request populated inside that window would
+// otherwise be signed and sent at a nonce this wallet has already used.
+//
+// The record dies with the worker, which is correct rather than merely
+// convenient: after a restart the node's count is the only answer available,
+// and a transaction of this wallet's that the node has forgotten is one the
+// user does want to be able to send again.
+const broadcastNonces = {};
+
+function broadcastNoncesFor(address) {
+    const key = String(address || "").toLowerCase();
+    if (!broadcastNonces[key]) broadcastNonces[key] = new Set();
+    return broadcastNonces[key];
+}
+
+// An approved transaction's nonce as a decimal string, or null if it cannot be
+// read as a number. Verification refuses an unreadable nonce before this is
+// ever reached; null here only keeps the record from holding junk.
+function approvedNonce(approvedTx) {
+    try {
+        return BigInt(approvedTx.nonce).toString();
+    } catch {
+        return null;
+    }
+}
+
 async function getState() {
     const result = await storageApi.get("autistmask");
     return (
@@ -585,10 +661,46 @@ async function handleRpc(method, params, origin) {
     }
 
     if (method === "eth_sendTransaction") {
+        // Synchronous, before any await: two requests delivered in the same
+        // tick must not both get past this.
+        if (!reserveTxApprovalSlot()) {
+            return {
+                error: {
+                    code: TX_APPROVAL_PENDING_CODE,
+                    message: TX_APPROVAL_PENDING_MESSAGE,
+                },
+            };
+        }
+        try {
+            return await handleSendTransaction(params, origin);
+        } finally {
+            // Held until the page has its answer — the approval was broadcast,
+            // rejected, or retired by a closed window — because until then its
+            // nonce is allocated and unspent.
+            releaseTxApprovalSlot();
+        }
+    }
+
+    // Proxy safe read-only methods to the RPC node
+    if (PROXY_METHODS.includes(method)) {
+        try {
+            const result = await proxyRpc(method, params);
+            return { result };
+        } catch (e) {
+            return { error: { message: e.message } };
+        }
+    }
+
+    return { error: { message: "Unsupported method: " + method } };
+}
+
+// The body of eth_sendTransaction, from the connection check through to the
+// user's decision. Its caller holds the single transaction-approval slot for
+// as long as this runs.
+async function handleSendTransaction(params, origin) {
     const s = await getState();
     const activeAddress = await getActiveAddress();
-        if (!activeAddress)
+    if (!activeAddress) return { error: { message: "No accounts available" } };
-            return { error: { message: "No accounts available" } };
 
     const hostname = extractHostname(origin);
     const allowed = s.allowedSites[activeAddress] || [];
@@ -649,19 +761,6 @@ async function handleRpc(method, params, origin) {
     return { result: decision.txHash };
 }
 
-    // Proxy safe read-only methods to the RPC node
-    if (PROXY_METHODS.includes(method)) {
-        try {
-            const result = await proxyRpc(method, params);
-            return { result };
-        } catch (e) {
-            return { error: { message: e.message } };
-        }
-    }
-
-    return { error: { message: "Unsupported method: " + method } };
-}
-
 // Broadcast chainChanged to all tabs when the network is switched.
 function broadcastChainChanged(chainId) {
     tabsApi.query({}, (tabs) => {
@@ -959,7 +1058,7 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
             sendResponse({
                 error: outcome.error,
                 retryable: outcome.retryable,
-                stage: TX_STAGE_SIGN,
+                stage: outcome.stage,
             });
             return false;
         }
@@ -1019,7 +1118,28 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
                 sendResponse({
                     error: outcome.error,
                     retryable: outcome.retryable,
-                    stage: TX_STAGE_VERIFY,
+                    stage: outcome.stage,
+                });
+                return;
+            }
+
+            // A nonce this worker has already broadcast for this address. The
+            // node is not asked: it has answered once already, and the wallet
+            // holding the receipt of that answer is what makes this failure
+            // one the user can be told did not reach the network.
+            const nonce = approvedNonce(approval.approvedTx);
+            const spent = broadcastNoncesFor(approval.approvedFrom);
+            if (nonce !== null && spent.has(nonce)) {
+                const outcome = describeTxFailure(TX_STAGE_NONCE, null);
+                settleApproval(
+                    msg.id,
+                    { error: { message: outcome.error } },
+                    { holdsClaim: true },
+                );
+                sendResponse({
+                    error: outcome.error,
+                    retryable: outcome.retryable,
+                    stage: outcome.stage,
                 });
                 return;
             }
@@ -1027,6 +1147,7 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
             try {
                 const provider = getProvider(state.rpcUrl);
                 const tx = await provider.broadcastTransaction(msg.rawSignedTx);
+                if (nonce !== null) spent.add(nonce);
                 settleApproval(
                     msg.id,
                     { txHash: tx.hash },
@@ -1039,6 +1160,11 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
                 // tell a transaction that never left from one already in the
                 // mempool. The page has been given its outcome for this
                 // request; a second attempt would report a second one.
+                //
+                // Unless the node blamed the nonce, which is the one answer
+                // that says plainly it did not take the transaction:
+                // describeTxFailure() reclassifies that, and the stage it
+                // returns is the one reported.
                 const outcome = describeTxFailure(TX_STAGE_BROADCAST, e);
                 settleApproval(
                     msg.id,
@@ -1048,7 +1174,7 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
                 sendResponse({
                     error: outcome.error,
                     retryable: outcome.retryable,
-                    stage: TX_STAGE_BROADCAST,
+                    stage: outcome.stage,
                 });
             }
         })();

src/content/inpage.js

@@ -11,6 +11,39 @@
     let nextId = 1;
     const pending = {};
 
+    // EIP-1193 ProviderRpcError: `code`, `message`, optional `data`. A class
+    // rather than properties bolted onto an Error because this object crosses
+    // no boundary after construction — it is built in the page's own realm and
+    // handed straight to the caller's catch — so the prototype survives and
+    // `error.name` is a stable thing for a dApp to see.
+    class ProviderRpcError extends Error {
+        constructor(code, message, data) {
+            super(message);
+            this.name = "ProviderRpcError";
+            this.code = code;
+            if (data !== undefined) this.data = data;
+        }
+    }
+
+    // Rebuild a boundary error as the error the page catches, carrying the
+    // code (and data) the extension reported. Without this a dApp cannot tell
+    // a user's refusal (4001) from a wallet that broke, and retries or shows
+    // an error instead of accepting the refusal.
+    //
+    // Whatever code arrived is passed through verbatim rather than being
+    // matched against a list: the extension emits 4001, 4100 and 4902 today,
+    // and a code this file has never heard of is still the truth about what
+    // happened. An error reported with no code at all stays a plain Error —
+    // a ProviderRpcError whose `code` is undefined would advertise a
+    // conformance it does not have. `message` is untouched in every case.
+    function toPageError(error) {
+        const message = (error && error.message) || "Request failed";
+        if (error && error.code !== undefined && error.code !== null) {
+            return new ProviderRpcError(error.code, message, error.data);
+        }
+        return new Error(message);
+    }
+
     // Listen for responses from the content script
     window.addEventListener("message", function onUuid(event) {
         if (event.source !== window) return;
@@ -20,7 +53,7 @@
         if (!p) return;
         delete pending[id];
         if (error) {
-            p.reject(new Error(error.message || "Request failed"));
+            p.reject(toPageError(error));
         } else {
             p.resolve(result);
         }

src/popup/index.js

@@ -9,17 +9,16 @@ const {
     $,
     showView,
     updateDebugBanner,
-    setBackRenderer,
+    setRenderMain,
     pushCurrentView,
     goBack,
     clearViewStack,
 } = require("./views/helpers");
 const { applyTheme } = require("./theme");
-// Renders a view the popup lands on without having navigated to it forward:
+// Views that can be fully re-rendered from persisted state. All others fall
-// on restore here, and on Back. Only the views that can be fully re-rendered
+// back to the nearest restorable parent; see the module for why the
-// from persisted state (RESTORABLE_VIEWS, src/popup/restorableViews.js) go
+// secret-bearing views are absent.
-// through it; anything else falls back to the nearest restorable parent.
+const { RESTORABLE_VIEWS } = require("./restorableViews");
-const { renderView, makeBackRenderer } = require("./viewRouter");
 
 const home = require("./views/home");
 const welcome = require("./views/welcome");
@@ -109,23 +108,92 @@ const ctx = {
     },
 };
 
-// The view modules the router renders through, keyed as it expects them.
+function needsAddress(view) {
-const viewModules = {
+    return (
-    main: { show: () => fallbackView() },
+        view === "address" ||
-    addressDetail,
+        view === "address-token" ||
-    addressToken,
+        view === "receive" ||
-    receive,
+        view === "transaction"
-    settings,
+    );
-    settingsAddToken,
+}
-    confirmTx,
+
-    transactionDetail,
+function hasValidAddress() {
-    txStatus,
+    return (
-};
+        state.selectedWallet !== null &&
+        state.selectedAddress !== null &&
+        state.wallets[state.selectedWallet] &&
+        state.wallets[state.selectedWallet].addresses[state.selectedAddress]
+    );
+}
 
 function restoreView() {
-    if (!renderView(state.currentView, state, viewModules)) {
+    const view = state.currentView;
+    if (!view || !RESTORABLE_VIEWS.has(view)) {
+        return fallbackView();
+    }
+
+    if (needsAddress(view) && !hasValidAddress()) {
+        return fallbackView();
+    }
+
+    if (view === "address-token" && !state.selectedToken) {
+        return fallbackView();
+    }
+
+    switch (view) {
+        case "address":
+            addressDetail.show();
+            break;
+        case "address-token":
+            addressToken.show();
+            break;
+        case "receive":
+            receive.show();
+            break;
+        case "settings":
+            settings.show();
+            break;
+        case "settings-addtoken":
+            settingsAddToken.show();
+            break;
+        case "confirm-tx":
+            if (state.viewData && state.viewData.pendingTx) {
+                confirmTx.restore();
+            } else {
                 fallbackView();
             }
+            break;
+        case "transaction":
+            if (state.viewData && state.viewData.tx) {
+                transactionDetail.render();
+            } else {
+                fallbackView();
+            }
+            break;
+        case "wait-tx":
+            // Resumes the receipt poll from the persisted broadcast time.
+            if (!txStatus.restoreWait()) {
+                fallbackView();
+            }
+            break;
+        case "success-tx":
+            if (state.viewData && state.viewData.hash) {
+                txStatus.renderSuccess();
+            } else {
+                fallbackView();
+            }
+            break;
+        case "error-tx":
+            if (state.viewData && state.viewData.message) {
+                txStatus.renderError();
+            } else {
+                fallbackView();
+            }
+            break;
+        default:
+            fallbackView();
+            break;
+    }
 }
 
 function fallbackView() {
@@ -179,7 +247,7 @@ async function init() {
         settings.show();
     });
 
-    setBackRenderer(makeBackRenderer(state, viewModules));
+    setRenderMain(renderWalletList);
 
     welcome.init(ctx);
     addWallet.init(ctx);

src/popup/viewRouter.js

@@ -1,116 +0,0 @@
-// Rendering a view the popup lands on without having navigated to it
-// forward: on restore, and on Back. In both cases the view may never have
-// been rendered in this page load — a reopened popup renders only the
-// wallet list and the view it restores onto, so every other view is still
-// the blank static template from index.html — so unhiding it is not enough.
-//
-// Forward navigation renders as it goes and must NOT come through here:
-// rendering a second time would re-fetch and clobber whatever the view has
-// in flight.
-//
-// The view modules are injected and nothing here touches the DOM, so the
-// dispatch and its data guards can be tested directly; src/popup/index.js
-// cannot be required outside a browser.
-
-const { RESTORABLE_VIEWS } = require("./restorableViews");
-
-// Views that render an address the user picked and cannot be rendered
-// without one.
-const ADDRESS_VIEWS = new Set([
-    "address",
-    "address-token",
-    "receive",
-    "transaction",
-]);
-
-function needsAddress(view) {
-    return ADDRESS_VIEWS.has(view);
-}
-
-function hasValidAddress(state) {
-    return Boolean(
-        state.selectedWallet !== null &&
-        state.selectedAddress !== null &&
-        state.wallets[state.selectedWallet] &&
-        state.wallets[state.selectedWallet].addresses[state.selectedAddress],
-    );
-}
-
-// Render `view` from persisted state. Each view module shows itself, so a
-// true return means the view is both rendered and on screen.
-//
-// Returns false when the view is not one the popup renders from state, or
-// when the state it would render is gone — a token no longer selected, a
-// transaction no longer persisted. The caller falls back rather than
-// putting an empty template on screen.
-function renderView(view, state, views) {
-    if (!view || !RESTORABLE_VIEWS.has(view)) return false;
-    if (needsAddress(view) && !hasValidAddress(state)) return false;
-    if (view === "address-token" && !state.selectedToken) return false;
-
-    const data = state.viewData || {};
-    switch (view) {
-        case "main":
-            views.main.show();
-            return true;
-        case "address":
-            views.addressDetail.show();
-            return true;
-        case "address-token":
-            views.addressToken.show();
-            return true;
-        case "receive":
-            views.receive.show();
-            return true;
-        case "settings":
-            views.settings.show();
-            return true;
-        case "settings-addtoken":
-            views.settingsAddToken.show();
-            return true;
-        case "confirm-tx":
-            if (!data.pendingTx) return false;
-            views.confirmTx.restore();
-            return true;
-        case "transaction":
-            if (!data.tx) return false;
-            views.transactionDetail.render();
-            return true;
-        case "wait-tx":
-            // Resumes the receipt poll from the persisted broadcast time,
-            // and answers false when there is nothing resumable left.
-            return Boolean(views.txStatus.restoreWait());
-        case "success-tx":
-            if (!data.hash) return false;
-            views.txStatus.renderSuccess();
-            return true;
-        case "error-tx":
-            if (!data.message) return false;
-            views.txStatus.renderError();
-            return true;
-        default:
-            return false;
-    }
-}
-
-// The Back-path renderer, registered with setBackRenderer() in
-// views/helpers.js. Returns false for a view the popup does not render from
-// persisted state, leaving goBack() to unhide it: the restored stack is
-// filtered against RESTORABLE_VIEWS, so such a view can only be on the
-// stack from this page load, where forward navigation already rendered it.
-function makeBackRenderer(state, views) {
-    return function renderBack(view) {
-        if (!RESTORABLE_VIEWS.has(view)) return false;
-        if (!renderView(view, state, views)) {
-            views.main.show();
-        }
-        return true;
-    };
-}
-
-module.exports = {
-    renderView,
-    makeBackRenderer,
-    needsAddress,
-    hasValidAddress,
-};

src/popup/views/helpers.js

@@ -111,19 +111,12 @@ function updateDebugBanner(viewName) {
     }
 }
 
-// Callback that renders a view being navigated BACK onto. Set once by
+// Callback to re-render the main/home view when navigating back to it.
-// index.js via setBackRenderer(), which routes the view through the same
+// Set once by index.js via setRenderMain().
-// per-view render and data guards restoreView() uses.
+let _renderMain = null;
-//
-// It answers true when it took the navigation — the view is rendered and
-// shown, or its backing data was gone and it fell back — and false for a
-// view the popup does not render from persisted state. Those can only be
-// on the stack from this page load, because the stack is filtered on load,
-// so they have already been rendered and only need unhiding.
-let _renderBack = null;
 
-function setBackRenderer(fn) {
+function setRenderMain(fn) {
-    _renderBack = fn;
+    _renderMain = fn;
 }
 
 // Push the current view onto the navigation stack so goBack() can
@@ -143,11 +136,9 @@ function goBack() {
     } else {
         target = "main";
     }
-    // A popped view is landed on, not navigated to. If the popup has been
+    if (target === "main" && _renderMain) {
-    // closed and reopened since the view was pushed, nothing has ever
+        _renderMain();
-    // rendered it in this page load and its template is still blank, so it
+    }
-    // has to be rendered here rather than merely unhidden.
-    if (_renderBack && _renderBack(target)) return;
     showView(target);
 }
 
@@ -479,7 +470,7 @@ module.exports = {
     showView,
     onViewLeave,
     updateDebugBanner,
-    setBackRenderer,
+    setRenderMain,
     pushCurrentView,
     goBack,
     clearViewStack,

src/shared/approvalVerify.js

@@ -602,6 +602,12 @@ const TX_STAGE_BROADCAST = "broadcast";
 // may yet succeed, so the one thing the popup must not say is "start again
 // from the site".
 const TX_STAGE_INFLIGHT = "inflight";
+// A transaction refused for a nonce that is already spoken for, either by the
+// node's own answer or by this wallet's record of what it has broadcast. It is
+// the one broadcast-stage failure that is not ambiguous: the transaction was
+// not taken, so the user is told it did not reach the network and to send it
+// again, rather than being warned that it might already be out there.
+const TX_STAGE_NONCE = "nonce";
 
 function errorText(err) {
     if (typeof err === "string" && err !== "") return err;
@@ -611,6 +617,59 @@ function errorText(err) {
     return "The transaction could not be sent.";
 }
 
+// Every string a failure might carry its reason in. ethers reports the node's
+// own words in `shortMessage`, but a JSON-RPC error it could not classify is
+// nested under `error` or `info.error` with the node's message intact, and the
+// classification below has to see that too.
+function failureTexts(err) {
+    if (typeof err === "string") return [err];
+    if (!err || typeof err !== "object") return [];
+    const texts = [];
+    for (const text of [err.shortMessage, err.message, err.reason]) {
+        if (text) texts.push(String(text));
+    }
+    const nested = err.error || (err.info && err.info.error);
+    if (nested && nested.message) texts.push(String(nested.message));
+    return texts;
+}
+
+// What the Ethereum clients say when a transaction's nonce is already spoken
+// for: either it is below the account's next nonce, or another transaction is
+// sitting in the pool at that nonce and this one did not outbid it. Either way
+// the node answered, and its answer was that it did not take this transaction.
+//
+// "already known" is deliberately absent. A node that says it knows the
+// transaction has it, so that transaction did reach the network and the
+// ambiguous broadcast wording is the correct one for it.
+const NONCE_COLLISION_PATTERNS = [
+    /nonce too low/i,
+    /nonce has already been used/i,
+    /invalid nonce/i,
+    /oldnonce/i,
+    /replacement transaction underpriced/i,
+    /replacement fee too low/i,
+];
+
+// ethers' own classification of the same two conditions.
+const NONCE_COLLISION_CODES = ["NONCE_EXPIRED", "REPLACEMENT_UNDERPRICED"];
+
+// Whether a failed send is a nonce collision.
+function isNonceCollision(err) {
+    if (!err) return false;
+    if (err.code && NONCE_COLLISION_CODES.includes(err.code)) return true;
+    return failureTexts(err).some((text) =>
+        NONCE_COLLISION_PATTERNS.some((pattern) => pattern.test(text)),
+    );
+}
+
+// What both the requesting page and the popup are told about a nonce
+// collision. The node's own words ("nonce too low") are a fragment and are
+// replaced rather than passed through: they are not a sentence, and they say
+// less than the wallet knows.
+const NONCE_COLLISION_MESSAGE =
+    "The transaction was not sent, because its nonce had already been used" +
+    " by another transaction.";
+
 // What the background does with a pending transaction approval after a failed
 // attempt: what it tells the popup, and whether the approval is spent
 // (resolved to the requesting page as an error and deleted) or left standing
@@ -627,12 +686,31 @@ function errorText(err) {
 //    that never left from one that is already in the mempool. The approval is
 //    spent and the requesting page has been given its outcome; a second
 //    attempt against it would report a second outcome for one request.
+//  - nonce: terminal too, and the one case where the wallet does know the
+//    transaction never left. The approval carries a nonce that is spent, so
+//    the artifact signed against it can never be accepted and the user is told
+//    to send it again from the site.
+//
+// The stage comes back out because a broadcast failure the node blamed on the
+// nonce is reclassified here; the caller reports the stage this returns rather
+// than the one it passed in.
 function describeTxFailure(stage, err) {
+    if (
+        stage === TX_STAGE_NONCE ||
+        (stage === TX_STAGE_BROADCAST && isNonceCollision(err))
+    ) {
+        return {
+            error: NONCE_COLLISION_MESSAGE,
+            retryable: false,
+            spendApproval: true,
+            stage: TX_STAGE_NONCE,
+        };
+    }
     const error = errorText(err);
     const retryable =
         stage === TX_STAGE_SIGN ||
         (stage === TX_STAGE_VERIFY && failureIsRetryable(err));
-    return { error, retryable, spendApproval: !retryable };
+    return { error, retryable, spendApproval: !retryable, stage };
 }
 
 // What the popup shows and does after the background reports a failed signing
@@ -642,14 +720,20 @@ function describeTxFailure(stage, err) {
 //
 // A failed broadcast gets its own wording: the transaction may already be on
 // the network, so telling the user to start again from the site is exactly the
-// wrong instruction.
+// wrong instruction. A nonce collision is the exception to that exception —
+// the transaction demonstrably did not go out, and saying it might have would
+// send the user hunting for a transaction that does not exist.
 function describeSigningFailure(response, fallbackMessage) {
     let message = (response && response.error) || fallbackMessage;
     if (!/[.!?]$/.test(message)) message += ".";
     const retryable = !!(response && response.retryable);
     const stage = response && response.stage;
     if (!retryable) {
-        if (stage === TX_STAGE_BROADCAST) {
+        if (stage === TX_STAGE_NONCE) {
+            message +=
+                " The transaction did not reach the network." +
+                " Please send it again from the site.";
+        } else if (stage === TX_STAGE_BROADCAST) {
             message +=
                 " The transaction may still have reached the network." +
                 " Check the account before sending it again.";
@@ -675,9 +759,11 @@ module.exports = {
     assertWithinCeilings,
     sameAddress,
     failureIsRetryable,
+    isNonceCollision,
     describeTxFailure,
     describeSigningFailure,
     ApprovalMismatchError,
+    NONCE_COLLISION_MESSAGE,
     ALLOWED_TX_TYPES,
     SERIALIZED_FIELDS,
     FORBIDDEN_FIELDS,
@@ -686,6 +772,7 @@ module.exports = {
     TX_STAGE_VERIFY,
     TX_STAGE_BROADCAST,
     TX_STAGE_INFLIGHT,
+    TX_STAGE_NONCE,
     MAX_GAS_LIMIT,
     MAX_FEE_PER_GAS,
 };

src/shared/balances.js

@@ -66,7 +66,12 @@ async function fetchTokenBalances(address, blockscoutUrl, trackedTokens) {
 
         const balances = [];
         for (const item of items) {
-            if (item.token?.type !== "ERC-20") continue;
+            // Case-insensitive: the token type is an explorer's label, not a
+            // protocol value, and an exact comparison silently drops a real
+            // holding if one ever writes "erc-20".  Which types are admitted
+            // is unchanged.
+            const type = String(item.token?.type || "").toUpperCase();
+            if (type !== "ERC-20") continue;
             const decimals = parseInt(item.token.decimals || "18", 10);
             const bal = formatTokenBalance(item.value || "0", decimals);
             if (bal === "0.0") continue;

src/shared/symbolSpoof.js

@@ -8,11 +8,23 @@
 // either verdict alone, because the balance list is where the user forms
 // their belief about what they own (issue #235).
 //
-// KNOWN_SYMBOLS maps a symbol to the lowercased contract address that may
+// KNOWN_SYMBOLS maps a symbol to the set of lowercased contract addresses
-// bear it, or to null.  Null means the symbol belongs to the native asset,
+// that may bear it, or to null.  Null means the symbol belongs to the native
-// which has no contract at all, so no contract may bear it and every one
+// asset, which has no contract at all, so no contract may bear it and every
-// that does is a spoof.  "ETH" is the only such entry today; the rule is
+// one that does is a spoof.  "ETH" is the only such entry today; the rule is
 // written so that a second one needs no change here or at any call site.
+//
+// The value is a set because a ticker is not unique: seven symbols in the
+// bundled list belong to two real contracts each, and answering with one of
+// them hid the other one's holders' money (issue #276).  Membership, not
+// equality, is therefore the question — but it is the same question, asked of
+// a table that can now state the truth.  Every address in a set is one the
+// wallet ships as a real token; a contract outside the set is still a spoof.
+//
+// The symbol is attacker-controlled — it is whatever the ERC-20 contract
+// returns — so the lookup is done on a normalized form (issue #260): the
+// question is whether the symbol reaches the user's eye as a known one,
+// since that is what the user acts on.
 
 const { KNOWN_SYMBOLS } = require("./tokenList");
 
@@ -22,6 +34,59 @@ function normalizeAddress(addr) {
     return (addr || "").toLowerCase();
 }
 
+// Fold a symbol onto what a user actually sees, and no further:
+//
+//   NFKC        collapses compatibility variants that render as the ASCII
+//               letters they imitate — fullwidth ETH, styled mathematical
+//               letters — and maps the non-ASCII spaces onto U+0020.
+//   strip       drops what paints nothing: \p{Cf} plus
+//               \p{Default_Ignorable_Code_Point} plus U+007F.  That covers
+//               the format characters (zero-width space, joiner and
+//               non-joiner, word joiner, soft hyphen, byte-order mark, bidi
+//               marks and overrides), the variation selectors, the Hangul
+//               fillers, and DELETE.  Removed everywhere, not merely at the
+//               ends.
+//   trim        removes surrounding whitespace, which HTML collapses:
+//               `" ETH "` is painted next to the user's real ETH as `ETH`.
+//   toUpperCase makes the comparison case-insensitive, as before.
+//
+// The rule is "strip what paints nothing".  The Unicode classes are how
+// that is spelled, not what it means, which is why U+007F is named on its
+// own: it is a control rather than a default-ignorable character, so no
+// class here reaches it, yet it paints nothing all the same.  Measured in
+// the repo's pinned e2e Chromium (16px sans-serif, plain `ETH` = 32.00px,
+// so an invisible prefix leaves 32.00px):
+//
+//   U+007F, U+3164, U+115F, U+FE0F, U+FE00   32.00px — invisible
+//   U+FFA0                                   40.00px — a box
+//   U+1160                                   48.00px — a box
+//   U+0001, U+0085, U+0090                   48.00px — a box
+//
+// U+1160 and U+FFA0 are `Default_Ignorable_Code_Point` members that font
+// fallback nonetheless draws, and they are stripped anyway: erring toward
+// hiding a token that does not look like `ETH` is the harmless direction of
+// the two.  The other controls are left alone for the same reason read the
+// other way — a symbol carrying a visible box does not reach the eye as
+// `ETH`, so filtering it would hide a token the user could not have
+// confused with the native asset.
+//
+// Deliberately not folded, and asserted as open in tests/symbolSpoof.test.js:
+// interior whitespace (`E T H` renders as `E T H`, so folding it would filter
+// a token nobody could confuse with the native asset), confusables that are
+// distinct letters rather than compatibility variants (Cyrillic capital Ie,
+// U+0415; Greek capital Epsilon, U+0395), bidi reordering, which needs the
+// bidi algorithm rather than a character filter, and the visible controls.
+//
+// This decides only how the question is asked.  Nothing here changes what a
+// surface displays; a token still shows the symbol it reports.
+function normalizeSymbol(symbol) {
+    return String(symbol || "")
+        .normalize("NFKC")
+        .replace(/[\p{Cf}\p{Default_Ignorable_Code_Point}\x7F]/gu, "")
+        .trim()
+        .toUpperCase();
+}
+
 // True when a token bearing `symbol` from contract `contractAddress` is
 // impersonating a known symbol.
 //
@@ -31,11 +96,11 @@ function normalizeAddress(addr) {
 function isSpoofedSymbol(symbol, contractAddress) {
     const contract = normalizeAddress(contractAddress);
     if (!contract) return false;
-    const sym = (symbol || "").toUpperCase();
+    const sym = normalizeSymbol(symbol);
     if (!KNOWN_SYMBOLS.has(sym)) return false;
     const legit = KNOWN_SYMBOLS.get(sym);
     if (legit === null) return true;
-    return contract !== normalizeAddress(legit);
+    return !legit.has(contract);
 }
 
 module.exports = {

src/shared/tokenList.js

@@ -3607,14 +3607,33 @@ for (const t of TOKENS) {
     TOKEN_BY_ADDRESS.set(t.address.toLowerCase(), t);
 }
 
-// Build a map of symbol (uppercased) -> legitimate contract address (lowercased).
+// Build a map of symbol (uppercased) -> the set of contract addresses
-// Used for spoofed-symbol detection. "ETH" maps to null (native token).
+// (lowercased) that legitimately bear it.  Used for spoofed-symbol detection.
+// "ETH" maps to null: the native asset has no contract, so no contract may
+// bear its symbol.
+//
+// The value is a set and not a single address because tickers are not unique
+// and the list above proves it: seven of these 512 tokens share a symbol with
+// another entry — FRAX, REUSD, TON, EURE, MSUSD, MUSD and JPYC — at two
+// different real contracts each, all of them from the same source fetch.  A
+// one-address-per-symbol table can only answer that by picking a winner, and
+// the loser is then a token in our own bundled list that the spoof filter
+// hides from the balance list, the history and the send selector at its own
+// address, so the user cannot spend it (issue #276).  Naming every address
+// that bears the symbol is the only shape that says what is true; it does not
+// loosen the rule, because a contract outside the set is still a spoof.
 const KNOWN_SYMBOLS = new Map();
 KNOWN_SYMBOLS.set("ETH", null);
 for (const t of TOKENS) {
     const upper = t.symbol.toUpperCase();
     if (!KNOWN_SYMBOLS.has(upper)) {
-        KNOWN_SYMBOLS.set(upper, t.address.toLowerCase());
+        KNOWN_SYMBOLS.set(upper, new Set());
+    }
+    const addresses = KNOWN_SYMBOLS.get(upper);
+    // A null entry is the native asset and stays null: an ERC-20 that reports
+    // the native symbol does not thereby become entitled to it.
+    if (addresses !== null) {
+        addresses.add(t.address.toLowerCase());
     }
 }
 

tests/approvalVerify.test.js

@@ -14,8 +14,10 @@ const {
     assertWithinCeilings,
     sameAddress,
     failureIsRetryable,
+    isNonceCollision,
     describeTxFailure,
     describeSigningFailure,
+    NONCE_COLLISION_MESSAGE,
     ALLOWED_TX_TYPES,
     SERIALIZED_FIELDS,
     FORBIDDEN_FIELDS,
@@ -23,6 +25,7 @@ const {
     TX_STAGE_SIGN,
     TX_STAGE_VERIFY,
     TX_STAGE_BROADCAST,
+    TX_STAGE_NONCE,
     MAX_GAS_LIMIT,
     MAX_FEE_PER_GAS,
 } = require("../src/shared/approvalVerify");
@@ -1191,7 +1194,6 @@ describe("signing failure and retry", () => {
             "already known",
             "timeout of 30000ms exceeded",
             "could not coalesce error",
-            "replacement transaction underpriced",
         ]) {
             const outcome = describeTxFailure(
                 TX_STAGE_BROADCAST,
@@ -1199,10 +1201,76 @@ describe("signing failure and retry", () => {
             );
             expect(outcome.retryable).toBe(false);
             expect(outcome.spendApproval).toBe(true);
+            expect(outcome.stage).toBe(TX_STAGE_BROADCAST);
             expect(outcome.error).toBe(message);
         }
     });
 
+    // The one broadcast failure that is not ambiguous. The node answered, and
+    // its answer was that the nonce was already spoken for, so this
+    // transaction is not in a mempool anywhere.
+    test("a nonce the node refused is classified however it was worded", () => {
+        for (const err of [
+            new Error("nonce too low"),
+            new Error("replacement transaction underpriced"),
+            Object.assign(new Error("could not coalesce error"), {
+                code: "NONCE_EXPIRED",
+            }),
+            Object.assign(new Error("could not coalesce error"), {
+                code: "REPLACEMENT_UNDERPRICED",
+            }),
+            // The shape ethers hands up when it could not classify the node's
+            // error itself: the node's own words are nested underneath.
+            Object.assign(new Error("could not coalesce error"), {
+                info: { error: { code: -32000, message: "OldNonce" } },
+            }),
+        ]) {
+            const outcome = describeTxFailure(TX_STAGE_BROADCAST, err);
+            expect(
+                describeSigningFailure(
+                    outcome,
+                    "The transaction could not be sent.",
+                ).message,
+            ).toMatch(/did not reach the network/);
+            expect(outcome.retryable).toBe(false);
+            expect(outcome.spendApproval).toBe(true);
+            expect(outcome.error).toBe(NONCE_COLLISION_MESSAGE);
+            expect(outcome.stage).toBe(TX_STAGE_NONCE);
+            expect(isNonceCollision(err)).toBe(true);
+        }
+    });
+
+    // A node that says it knows the transaction has it, so it did reach the
+    // network and the ambiguous wording is the correct one.
+    test("already known is not a nonce collision", () => {
+        const err = new Error("already known");
+        const outcome = describeTxFailure(TX_STAGE_BROADCAST, err);
+        expect(
+            describeSigningFailure(
+                outcome,
+                "The transaction could not be sent.",
+            ).message,
+        ).toMatch(/may still have reached the network/);
+        expect(outcome.stage).toBe(TX_STAGE_BROADCAST);
+        expect(isNonceCollision(err)).toBe(false);
+    });
+
+    test("a nonce collision says the transaction did not reach the network", () => {
+        const outcome = describeTxFailure(
+            TX_STAGE_BROADCAST,
+            new Error("nonce too low"),
+        );
+        const copy = describeSigningFailure(
+            outcome,
+            "The transaction could not be sent.",
+        );
+        expect(copy.retryable).toBe(false);
+        expect(copy.message).toMatch(/did not reach the network/);
+        expect(copy.message).not.toMatch(/may still have reached the network/);
+        expect(copy.message).toMatch(/Please send it again from the site\.$/);
+        expect(copy.message).toMatch(/^[A-Z].*\.$/);
+    });
+
     test("a failed broadcast does not tell the user to send it again", () => {
         const outcome = describeSigningFailure(
             {

tests/backNavigation.test.js

@@ -1,243 +0,0 @@
-// Back after reopening the popup (#268).
-//
-// A reopened popup renders the wallet list and the one view it restores
-// onto; every other view is still the blank static template from
-// index.html. goBack() used to only unhide its target, so Back landed on
-// that blank template for any view the popup had not rendered in this page
-// load. These tests drive the real goBack() with the real router wired to
-// recording view modules, so what is asserted is which view render ran —
-// the thing that was missing.
-//
-// The rendering itself is asserted against the real popup in a real
-// browser by tests/e2e/run.js; here the DOM is a stub, because goBack()
-// only needs showView() to work.
-
-const els = new Map();
-
-function fakeEl() {
-    return {
-        textContent: "",
-        innerHTML: "",
-        classList: {
-            toggle() {},
-            add() {},
-            remove() {},
-            contains: () => false,
-        },
-        remove() {},
-    };
-}
-
-globalThis.document = {
-    getElementById(id) {
-        if (!els.has(id)) els.set(id, fakeEl());
-        return els.get(id);
-    },
-};
-
-// helpers.js pulls in state.js, which reads chrome.storage.local at load.
-globalThis.chrome = {
-    storage: { local: { get: async () => ({}), set: async () => {} } },
-};
-
-const {
-    showView,
-    goBack,
-    setBackRenderer,
-    pushCurrentView,
-} = require("../src/popup/views/helpers");
-const { makeBackRenderer } = require("../src/popup/viewRouter");
-const { state } = require("../src/shared/state");
-
-const ADDRESS = "0x1111111111111111111111111111111111111111";
-const TOKEN = "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48";
-
-let calls;
-
-// Stand-ins for the view modules. Each records itself and then shows its
-// view, which is what every real view render ends with — so the assertions
-// can tell "rendered and shown" apart from "merely unhidden".
-function recorder(name, view) {
-    return () => {
-        calls.push(name);
-        showView(view);
-    };
-}
-
-function makeViews() {
-    return {
-        main: { show: recorder("main", "main") },
-        addressDetail: { show: recorder("addressDetail", "address") },
-        addressToken: { show: recorder("addressToken", "address-token") },
-        receive: { show: recorder("receive", "receive") },
-        settings: { show: recorder("settings", "settings") },
-        settingsAddToken: {
-            show: recorder("settingsAddToken", "settings-addtoken"),
-        },
-        confirmTx: { restore: recorder("confirmTx", "confirm-tx") },
-        transactionDetail: {
-            render: recorder("transactionDetail", "transaction"),
-        },
-        txStatus: {
-            restoreWait: () => {
-                calls.push("waitTx");
-                showView("wait-tx");
-                return true;
-            },
-            renderSuccess: recorder("successTx", "success-tx"),
-            renderError: recorder("errorTx", "error-tx"),
-        },
-    };
-}
-
-// The popup as it stands just after a reopen: one wallet with one address,
-// the view the popup restored onto, and the stack behind it.
-function reopenedOn(view, stack, extra) {
-    calls = [];
-    state.wallets = [
-        {
-            name: "Wallet 1",
-            addresses: [{ address: ADDRESS, balance: "0", tokenBalances: [] }],
-        },
-    ];
-    state.selectedWallet = 0;
-    state.selectedAddress = 0;
-    state.selectedToken = null;
-    state.viewData = null;
-    state.currentView = view;
-    state.viewStack = stack.slice();
-    Object.assign(state, extra || {});
-    setBackRenderer(makeBackRenderer(state, makeViews()));
-}
-
-// The reproduction from the issue, step for step.
-describe("Back onto a view the reopened popup never rendered", () => {
-    test("Back from settings renders the address detail underneath", () => {
-        reopenedOn("settings", ["main", "address"]);
-        goBack();
-        expect(calls).toEqual(["addressDetail"]);
-        expect(state.currentView).toBe("address");
-        expect(state.viewStack).toEqual(["main"]);
-    });
-
-    test("Back onto the token detail renders it", () => {
-        reopenedOn("settings", ["main", "address", "address-token"], {
-            selectedToken: TOKEN,
-        });
-        goBack();
-        expect(calls).toEqual(["addressToken"]);
-        expect(state.currentView).toBe("address-token");
-    });
-
-    test("Back onto Receive renders it", () => {
-        reopenedOn("settings", ["main", "address", "receive"]);
-        goBack();
-        expect(calls).toEqual(["receive"]);
-        expect(state.currentView).toBe("receive");
-    });
-
-    test("Back onto the transaction detail renders it", () => {
-        reopenedOn("settings", ["main", "transaction"], {
-            viewData: { tx: { hash: "0xdead" } },
-        });
-        goBack();
-        expect(calls).toEqual(["transactionDetail"]);
-        expect(state.currentView).toBe("transaction");
-    });
-
-    test("Back onto the transaction confirmation restores it", () => {
-        reopenedOn("settings", ["main", "confirm-tx"], {
-            viewData: { pendingTx: { to: ADDRESS, amount: "1" } },
-        });
-        goBack();
-        expect(calls).toEqual(["confirmTx"]);
-        expect(state.currentView).toBe("confirm-tx");
-    });
-
-    test("Back onto Home renders the wallet list", () => {
-        reopenedOn("settings", ["main"]);
-        goBack();
-        expect(calls).toEqual(["main"]);
-        expect(state.currentView).toBe("main");
-    });
-
-    test("Back with an empty stack renders Home", () => {
-        reopenedOn("settings", []);
-        goBack();
-        expect(calls).toEqual(["main"]);
-        expect(state.currentView).toBe("main");
-    });
-});
-
-// The guards are restoreView()'s, so a popped view whose backing data is
-// gone lands on Home rather than on an empty template.
-describe("Back onto a view whose backing data is gone", () => {
-    test("the token detail with no token selected falls back to Home", () => {
-        reopenedOn("settings", ["main", "address-token"]);
-        goBack();
-        expect(calls).toEqual(["main"]);
-        expect(state.currentView).toBe("main");
-    });
-
-    test("the transaction detail with no transaction falls back to Home", () => {
-        reopenedOn("settings", ["main", "transaction"]);
-        goBack();
-        expect(calls).toEqual(["main"]);
-        expect(state.currentView).toBe("main");
-    });
-
-    test("the confirmation with no pending transaction falls back to Home", () => {
-        reopenedOn("settings", ["main", "confirm-tx"]);
-        goBack();
-        expect(calls).toEqual(["main"]);
-        expect(state.currentView).toBe("main");
-    });
-
-    test("an address view with no address selected falls back to Home", () => {
-        reopenedOn("settings", ["main", "receive"], {
-            selectedAddress: null,
-        });
-        goBack();
-        expect(calls).toEqual(["main"]);
-        expect(state.currentView).toBe("main");
-    });
-
-    test("a wait that can no longer be resumed falls back to Home", () => {
-        reopenedOn("settings", ["main", "wait-tx"]);
-        const views = makeViews();
-        views.txStatus.restoreWait = () => false;
-        setBackRenderer(makeBackRenderer(state, views));
-        goBack();
-        expect(calls).toEqual(["main"]);
-        expect(state.currentView).toBe("main");
-    });
-});
-
-// Forward navigation renders as it goes. Re-rendering a second time would
-// re-fetch and clobber whatever the view has in flight, so the Back path is
-// the only place this happens — and it declines any view the popup does not
-// render from persisted state, since the restored stack is filtered against
-// that same set and such a view can only have been rendered in this page
-// load.
-describe("what the Back path leaves alone", () => {
-    test("forward navigation renders nothing by itself", () => {
-        reopenedOn("address", ["main"]);
-        pushCurrentView();
-        showView("send");
-        expect(calls).toEqual([]);
-        expect(state.viewStack).toEqual(["main", "address"]);
-    });
-
-    test("Back onto a live-session view only unhides it", () => {
-        reopenedOn("confirm-tx", ["main", "address", "send"]);
-        goBack();
-        expect(calls).toEqual([]);
-        expect(state.currentView).toBe("send");
-    });
-
-    test("Back renders its target exactly once", () => {
-        reopenedOn("settings", ["main", "address"]);
-        goBack();
-        expect(calls.filter((c) => c === "addressDetail")).toHaveLength(1);
-    });
-});

tests/backgroundApproval.test.js

@@ -206,6 +206,10 @@ function loadBackground(options) {
     // approval id back out of the popup URL the background opened.
     function requestTx(txParams) {
         let rpcResult = null;
+        // The window this request opens, if it opens one. A request refused
+        // before an approval is raised opens none, and the window belonging to
+        // some other request must not be handed back as this one's.
+        const windowIndex = created.length;
         const sendResponse = jest.fn((r) => {
             rpcResult = r;
         });
@@ -219,7 +223,12 @@ function loadBackground(options) {
             sendResponse,
         );
         return {
-            id: () => new URL(created[0].url).searchParams.get("approval"),
+            id: () =>
+                created.length > windowIndex
+                    ? new URL(created[windowIndex].url).searchParams.get(
+                          "approval",
+                      )
+                    : null,
             result: () => rpcResult,
         };
     }
@@ -444,6 +453,176 @@ describe("one approval, one broadcast", () => {
     });
 });
 
+// Populating the transaction before the approval window opens is what makes
+// the displayed object the verified object. It also fixes the nonce before the
+// user has answered anything: two requests populated concurrently take the
+// same nonce from a node that has seen neither of them broadcast, and the
+// second can then never be sent, because the only way to give it a fresh nonce
+// is to populate it again after the user has read the old one off the screen.
+// So the second request is refused while the first is unanswered.
+describe("one transaction approval at a time", () => {
+    test("a second eth_sendTransaction while one is pending is refused before it takes a nonce", async () => {
+        const getTransactionCount = jest.fn(async () => NONCE);
+        const bg = loadBackground({ provider: { getTransactionCount } });
+
+        const first = bg.requestTx();
+        await settle();
+        expect(first.id()).toBeTruthy();
+        expect(getTransactionCount).toHaveBeenCalledTimes(1);
+
+        const second = bg.requestTx();
+        await settle();
+
+        expect(second.result()).toEqual({
+            error: {
+                code: -32002,
+                message: expect.stringMatching(
+                    /already waiting to be approved/,
+                ),
+            },
+        });
+        // Where the refusal happened matters as much as that it happened: no
+        // second window, and the node was never asked for a second nonce.
+        expect(bg.created).toHaveLength(1);
+        expect(getTransactionCount).toHaveBeenCalledTimes(1);
+
+        // The refusal leaves the pending approval untouched, and it still
+        // sends.
+        bg.broadcastTransaction.mockResolvedValue({ hash: "0xfeed" });
+        bg.send(
+            {
+                type: "AUTISTMASK_TX_RESPONSE",
+                id: first.id(),
+                approved: true,
+                rawSignedTx: await signedAtNonce(NONCE),
+            },
+            { url: bg.fromPopup.url },
+        );
+        await settle();
+        expect(first.result()).toEqual({ result: "0xfeed" });
+    });
+
+    test("an answered approval frees the next request", async () => {
+        const bg = loadBackground();
+        const first = bg.requestTx();
+        await settle();
+
+        // The user closes the approval window, which rejects it.
+        bg.closeWindow(1);
+        await settle();
+        expect(first.result()).toEqual({
+            error: { code: 4001, message: "User rejected the request." },
+        });
+
+        const second = bg.requestTx();
+        await settle();
+        expect(second.id()).toBeTruthy();
+        expect(bg.created).toHaveLength(2);
+    });
+
+    test("a signature request is not held up by a pending transaction", async () => {
+        const bg = loadBackground();
+        bg.requestTx();
+        await settle();
+
+        // A signature consumes no nonce, so it has nothing to collide with.
+        const signing = bg.requestSign();
+        await settle();
+        expect(signing.id()).toBeTruthy();
+        expect(signing.result()).toBeNull();
+        expect(bg.created).toHaveLength(2);
+    });
+});
+
+// A nonce collision found before the transaction reaches the network is the
+// one send failure the wallet can speak about with certainty. The user is told
+// it did not go out and to send it again, rather than being warned it might
+// already be on the chain — which would send them looking for a transaction
+// that does not exist, and stop them retrying the one that never went.
+describe("a nonce collision is reported as a transaction that did not go out", () => {
+    test("a broadcast the node refused for the nonce is not reported as possibly sent", async () => {
+        const bg = loadBackground();
+        const pending = bg.requestTx();
+        await settle();
+
+        bg.broadcastTransaction.mockRejectedValue(
+            Object.assign(new Error("nonce too low"), {
+                code: "NONCE_EXPIRED",
+            }),
+        );
+        const answer = bg.send(
+            {
+                type: "AUTISTMASK_TX_RESPONSE",
+                id: pending.id(),
+                approved: true,
+                rawSignedTx: await signedAtNonce(NONCE),
+            },
+            { url: bg.fromPopup.url },
+        );
+        await settle();
+
+        expect(answer.sendResponse).toHaveBeenCalledWith({
+            error: expect.stringMatching(/nonce had already been used/),
+            retryable: false,
+            stage: "nonce",
+        });
+        expect(pending.result()).toEqual({
+            error: {
+                message: expect.stringMatching(
+                    /transaction was not sent, because its nonce/,
+                ),
+            },
+        });
+    });
+
+    test("a nonce this wallet already broadcast is refused without asking the node again", async () => {
+        const bg = loadBackground();
+        const first = bg.requestTx();
+        await settle();
+
+        bg.broadcastTransaction.mockResolvedValue({ hash: "0xfeed" });
+        bg.send(
+            {
+                type: "AUTISTMASK_TX_RESPONSE",
+                id: first.id(),
+                approved: true,
+                rawSignedTx: await signedAtNonce(NONCE),
+            },
+            { url: bg.fromPopup.url },
+        );
+        await settle();
+        expect(first.result()).toEqual({ result: "0xfeed" });
+
+        // The stubbed node still reports NONCE as the next nonce — a pending
+        // count that lags a broadcast the node has already taken — so this
+        // second approval is populated at a nonce this worker has spent.
+        const second = bg.requestTx();
+        await settle();
+        const answer = bg.send(
+            {
+                type: "AUTISTMASK_TX_RESPONSE",
+                id: second.id(),
+                approved: true,
+                rawSignedTx: await signedAtNonce(NONCE),
+            },
+            { url: bg.fromPopup.url },
+        );
+        await settle();
+
+        expect(bg.broadcastTransaction).toHaveBeenCalledTimes(1);
+        expect(answer.sendResponse).toHaveBeenCalledWith({
+            error: expect.stringMatching(/nonce had already been used/),
+            retryable: false,
+            stage: "nonce",
+        });
+        expect(second.result()).toEqual({
+            error: {
+                message: expect.stringMatching(/nonce had already been used/),
+            },
+        });
+    });
+});
+
 // The approval carries the transaction the user was shown and the address it
 // was raised for, and the artifact is checked against both. Every case here is
 // one the old comparison — against the dApp's request, for the address that is

tests/e2e/network.js

@@ -23,6 +23,8 @@
 
 "use strict";
 
+const { Transaction } = require("ethers");
+
 // Fictional ERC-20 used to seed the transaction-detail test. The symbol
 // must not collide with any entry in src/shared/tokenList.js, or
 // isSpoofedSymbol() in src/shared/transactions.js drops the transfer as a
@@ -62,6 +64,87 @@ function word(value) {
     return "0x" + BigInt(value).toString(16).padStart(64, "0");
 }
 
+// -------------------------------------------------------- dApp fixture
+//
+// The origin the EIP-1193 test page is served from, and the page itself.
+//
+// It is a fixture like every other one in this file: the route handler
+// fulfils the navigation from the string below, so the page never comes
+// from a remote origin and nothing about the dApp round trips leaves the
+// container. `.test` is reserved by RFC 6761 and has no owner to reach in
+// the first place; the launch arguments map every host to NOTFOUND anyway.
+//
+// What the page deliberately does NOT do is load a provider. window.ethereum
+// is put there by the shipped manifest's MAIN-world content script, exactly
+// as it is on any http(s) page a user visits, so what these tests speak to
+// is the real inpage provider and not a copy the harness wired up.
+const DAPP_ORIGIN = "https://dapp.e2e.test";
+const DAPP_URL = DAPP_ORIGIN + "/";
+
+// Requests are parked rather than awaited. An approval prompt only exists
+// while its call is in flight, so a test that awaited the promise could
+// never drive the popup that has to settle it; start() files the promise
+// under a key and settle() collects it once the prompt has been dealt with.
+//
+// The rejection branch records the whole observable shape of the error as it
+// arrives — name, message, and whether a `code` is present at all as distinct
+// from its value. EIP-1193 says a user rejection is a ProviderRpcError
+// carrying code 4001; what the page can actually see is recorded here rather
+// than assumed, and asserted in run.js.
+//
+// The message log is the page's half of the boundary observation: every
+// AUTISTMASK_* message that crosses between this page and the content
+// script, in both directions, verbatim.
+const DAPP_HTML = [
+    "<!doctype html>",
+    '<html lang="en">',
+    "<head>",
+    '<meta charset="utf-8">',
+    "<title>AutistMask e2e dApp</title>",
+    // Inline and empty: without it Chromium asks for /favicon.ico, which
+    // the unstubbed-request guard would report as escaping traffic.
+    '<link rel="icon" href="data:,">',
+    "</head>",
+    "<body>",
+    "<h1>AutistMask e2e dApp</h1>",
+    "<script>",
+    "window.__dapp = {",
+    "    messages: [],",
+    "    calls: {},",
+    "    start: function (key, method, params) {",
+    "        window.__dapp.calls[key] = window.ethereum",
+    "            .request({ method: method, params: params })",
+    "            .then(",
+    "                function (result) {",
+    "                    return { settled: 'resolved', result: result };",
+    "                },",
+    "                function (error) {",
+    "                    return {",
+    "                        settled: 'rejected',",
+    "                        message: String((error && error.message) || error),",
+    "                        name: error ? error.name : undefined,",
+    "                        hasCode: !!error && 'code' in Object(error),",
+    "                        code: error ? error.code : undefined,",
+    "                    };",
+    "                },",
+    "            );",
+    "    },",
+    "    settle: function (key) {",
+    "        return window.__dapp.calls[key];",
+    "    },",
+    "};",
+    "window.addEventListener('message', function (event) {",
+    "    if (event.source !== window) return;",
+    "    var d = event.data;",
+    "    if (!d || typeof d.type !== 'string') return;",
+    "    if (d.type.indexOf('AUTISTMASK') !== 0) return;",
+    "    window.__dapp.messages.push(d);",
+    "});",
+    "</script>",
+    "</body>",
+    "</html>",
+].join("\n");
+
 // ------------------------------------------------------------ fee fixture
 //
 // The confirmation screen carries two different numbers for the same
@@ -101,6 +184,11 @@ const RPC_RESULTS = {
     eth_estimateGas: hex(GAS_LIMIT),
     eth_getTransactionCount: "0x0",
     eth_maxPriorityFeePerGas: hex(PRIORITY_FEE_WEI),
+    // "not mined yet", which is what a node answers for a transaction it has
+    // only just accepted. The wait screen the dApp transaction approval hands
+    // off to polls this every 10 seconds; leaving it unstubbed would report
+    // the poll as escaping traffic the moment a test outlived one tick.
+    eth_getTransactionReceipt: null,
 };
 
 // The "latest" block, which ethers' getFeeData() reads baseFeePerGas from
@@ -264,6 +352,31 @@ function rpcReply(req, opts, report) {
     if (req.method === "eth_getBlockByNumber") {
         return Object.assign(envelope, { result: latestBlock() });
     }
+    // The end of the dApp transaction round trip: the raw signed transaction
+    // the background hands to the node. It is recorded verbatim so a test can
+    // recover the signer from the exact bytes that were broadcast, rather than
+    // from anything the extension reported about them.
+    //
+    // The reply must be the transaction's real hash. ethers compares the hash
+    // the node returns against the one it computes itself and throws on a
+    // mismatch, so a constant here would fail the broadcast for a reason that
+    // has nothing to do with what is being tested.
+    if (req.method === "eth_sendRawTransaction") {
+        const raw = Array.isArray(req.params) ? req.params[0] : null;
+        let parsed;
+        try {
+            parsed = Transaction.from(raw);
+        } catch {
+            report("eth_sendRawTransaction with an undecodable transaction");
+            return Object.assign(envelope, {
+                error: { code: -32000, message: "undecodable transaction" },
+            });
+        }
+        if (Array.isArray(opts.broadcastTransactions)) {
+            opts.broadcastTransactions.push(raw);
+        }
+        return Object.assign(envelope, { result: parsed.hash });
+    }
     if (req.method === "eth_estimateGas" && opts.failGasEstimate) {
         // A refusal the node itself would produce, not a transport error:
         // this is the shape the confirmation screen has to turn into
@@ -375,6 +488,8 @@ function traceEnabled(raw) {
  *   node-side refusal.
  * @param {boolean} [opts.holdGasEstimate]  hold every batch containing an
  *   eth_estimateGas until this is cleared again.
+ * @param {string[]} [opts.broadcastTransactions]  every raw signed
+ *   transaction handed to eth_sendRawTransaction, appended in order.
  * @returns {Promise<{waitForServiceWorkerTraffic: (ms: number) =>
  *   Promise<string|null>}>}
  */
@@ -420,6 +535,18 @@ async function installNetworkStubs(ctx, opts) {
             return handleRpc(route, req.postData(), opts, report);
         }
 
+        // The local EIP-1193 test page. Served from here so the dApp round
+        // trips run against a real http(s) origin — which is what makes the
+        // shipped content scripts inject at all — without any remote origin
+        // being involved.
+        if (url.origin === DAPP_ORIGIN && p === "/") {
+            return route.fulfill({
+                status: 200,
+                contentType: "text/html; charset=utf-8",
+                body: DAPP_HTML,
+            });
+        }
+
         // Blockscout v2
         if (p.includes("/api/v2/")) {
             if (/\/addresses\/0x[0-9a-fA-F]{40}\/transactions$/.test(p)) {
@@ -508,6 +635,8 @@ async function installNetworkStubs(ctx, opts) {
 
 module.exports = {
     installNetworkStubs,
+    DAPP_ORIGIN,
+    DAPP_URL,
     FEE_ESTIMATE_WEI,
     FEE_RESERVE_WEI,
     STUB_COUNTERPARTY,

tests/inpageErrors.test.js

@@ -0,0 +1,310 @@
+// The EIP-1193 error the page actually catches (src/content/inpage.js).
+//
+// The bug this pins down (issue #274): the provider rebuilt every failure as
+// `new Error(error.message)`, so the `code` the background produced and the
+// content script relayed intact was thrown away in the last hop. A dApp
+// checking `err.code === 4001` — the standard way to tell "the user said no"
+// from "the wallet broke" — saw undefined, and well-behaved sites showed an
+// error or retried instead of accepting the refusal.
+//
+// inpage.js is a bare IIFE injected into the page's JS context, not a module:
+// it takes no import and exports nothing, and reaches for `window` at load.
+// So it is evaluated here the way the browser evaluates it, against a stub
+// window, and the provider is collected from `window.ethereum`. The globals it
+// touches are passed in as function parameters rather than assigned to
+// globalThis: nothing leaks between tests, and the source is compiled in this
+// realm, so the errors it constructs are comparable against this file's own
+// `Error` — which a second realm's intrinsics would silently defeat.
+//
+// There is no jsdom in this repo; see tests/txStatus.test.js.
+
+const fs = require("fs");
+const path = require("path");
+const { webcrypto } = require("crypto");
+
+const SOURCE = fs.readFileSync(
+    path.join(__dirname, "..", "src", "content", "inpage.js"),
+    "utf8",
+);
+
+const loadInto = new Function(
+    "window",
+    "self",
+    "crypto",
+    "Event",
+    "CustomEvent",
+    SOURCE,
+);
+
+class StubEvent {
+    constructor(type) {
+        this.type = type;
+    }
+}
+
+class StubCustomEvent extends StubEvent {
+    constructor(type, init) {
+        super(type);
+        this.detail = init && init.detail;
+    }
+}
+
+// Every code the background emits on the RPC path today, read out of
+// src/background/index.js. The provider must not know this list — it passes
+// through whatever arrived — but the cases below are the real ones.
+const REJECTED = 4001; // user rejected the request
+const UNAUTHORIZED = 4100; // site not connected / wrong address
+const UNRECOGNIZED_CHAIN = 4902; // switch/add to an unsupported chain
+
+// A stub window with the four things inpage.js touches: message listeners,
+// postMessage out to the content script, window.ethereum, and dispatchEvent
+// for the EIP-6963 announcement.
+function loadProvider() {
+    const messageListeners = [];
+    const posted = [];
+
+    const win = {
+        addEventListener(type, fn) {
+            if (type === "message") messageListeners.push(fn);
+        },
+        removeEventListener(type, fn) {
+            const i = messageListeners.indexOf(fn);
+            if (type === "message" && i !== -1) messageListeners.splice(i, 1);
+        },
+        postMessage(data) {
+            posted.push(data);
+        },
+        dispatchEvent() {
+            return true;
+        },
+    };
+    win.window = win;
+
+    loadInto(win, win, webcrypto, StubEvent, StubCustomEvent);
+
+    // Deliver the content script's answer to an outstanding request. The id is
+    // read back off the wire rather than assumed: inpage.js issues its own
+    // eth_chainId at load, so the first id a test sees is not 1.
+    function respond(response) {
+        const request = posted
+            .filter((m) => m.type === "AUTISTMASK_REQUEST")
+            .pop();
+        expect(request).toBeDefined();
+        const event = {
+            source: win,
+            data: { type: "AUTISTMASK_RESPONSE", id: request.id, ...response },
+        };
+        for (const fn of messageListeners.slice()) fn(event);
+    }
+
+    return { provider: win.ethereum, posted, respond };
+}
+
+// Start a request, answer it with `response`, and hand back the rejection.
+// Fails the test if the call resolves instead.
+async function rejectionFrom(start, response) {
+    const { provider, respond } = loadProvider();
+    const settled = start(provider).then(
+        (result) => ({ resolved: result }),
+        (error) => ({ error }),
+    );
+    // The provider posts synchronously, so the request is already on the wire.
+    respond(response);
+    const outcome = await settled;
+    expect(outcome).not.toHaveProperty("resolved");
+    return outcome.error;
+}
+
+describe("an EIP-1193 code reaches the page", () => {
+    test("a user rejection arrives as code 4001", async () => {
+        const err = await rejectionFrom(
+            (p) => p.request({ method: "eth_requestAccounts" }),
+            {
+                error: {
+                    code: REJECTED,
+                    message: "User rejected the request.",
+                },
+            },
+        );
+        expect(err.code).toBe(REJECTED);
+        expect(err.message).toBe("User rejected the request.");
+    });
+
+    test("it is a ProviderRpcError, and an Error", async () => {
+        const err = await rejectionFrom(
+            (p) => p.request({ method: "eth_requestAccounts" }),
+            {
+                error: {
+                    code: REJECTED,
+                    message: "User rejected the request.",
+                },
+            },
+        );
+        expect(err).toBeInstanceOf(Error);
+        expect(err.name).toBe("ProviderRpcError");
+    });
+
+    test("4100 unauthorized arrives intact", async () => {
+        const err = await rejectionFrom(
+            (p) => p.request({ method: "personal_sign", params: ["0x00"] }),
+            { error: { code: UNAUTHORIZED, message: "Unauthorized" } },
+        );
+        expect(err.code).toBe(UNAUTHORIZED);
+        expect(err.message).toBe("Unauthorized");
+    });
+
+    test("4902 unrecognized chain arrives intact", async () => {
+        const message =
+            "AutistMask supports Ethereum Mainnet and Sepolia Testnet only.";
+        const err = await rejectionFrom(
+            (p) => p.request({ method: "wallet_switchEthereumChain" }),
+            { error: { code: UNRECOGNIZED_CHAIN, message } },
+        );
+        expect(err.code).toBe(UNRECOGNIZED_CHAIN);
+        expect(err.message).toBe(message);
+    });
+
+    // The provider is not allowed to know the list above: a code added to the
+    // background later must reach the page without this file being edited.
+    test("a code the provider has never heard of is passed through", async () => {
+        const err = await rejectionFrom(
+            (p) => p.request({ method: "eth_accounts" }),
+            { error: { code: 4900, message: "Disconnected" } },
+        );
+        expect(err.code).toBe(4900);
+    });
+
+    test("data is carried when the boundary sent it", async () => {
+        const err = await rejectionFrom(
+            (p) => p.request({ method: "eth_call" }),
+            {
+                error: {
+                    code: -32000,
+                    message: "execution reverted",
+                    data: "0x08c379a0",
+                },
+            },
+        );
+        expect(err.code).toBe(-32000);
+        expect(err.data).toBe("0x08c379a0");
+    });
+
+    test("no data property is invented when the boundary sent none", async () => {
+        const err = await rejectionFrom(
+            (p) => p.request({ method: "eth_requestAccounts" }),
+            {
+                error: {
+                    code: REJECTED,
+                    message: "User rejected the request.",
+                },
+            },
+        );
+        expect("data" in err).toBe(false);
+    });
+});
+
+describe("the message is untouched", () => {
+    test("a coded error keeps the message byte for byte", async () => {
+        const message =
+            "This site asked to sign as an address that is not " +
+            "the active one.";
+        const err = await rejectionFrom(
+            (p) => p.request({ method: "personal_sign" }),
+            { error: { code: UNAUTHORIZED, message } },
+        );
+        expect(err.message).toBe(message);
+    });
+
+    test("an error the background sent with no code keeps its message", async () => {
+        const err = await rejectionFrom(
+            (p) => p.request({ method: "eth_sendTransaction" }),
+            { error: { message: "No accounts available" } },
+        );
+        expect(err.message).toBe("No accounts available");
+    });
+
+    // A ProviderRpcError whose code is undefined would claim a conformance it
+    // does not have, and `'code' in err` is exactly what a careful dApp asks.
+    test("an error with no code gets no code property at all", async () => {
+        const err = await rejectionFrom(
+            (p) => p.request({ method: "eth_sendTransaction" }),
+            { error: { message: "No accounts available" } },
+        );
+        expect(err).toBeInstanceOf(Error);
+        expect("code" in err).toBe(false);
+    });
+
+    test("an error with no message keeps the generic fallback", async () => {
+        const err = await rejectionFrom(
+            (p) => p.request({ method: "eth_sendTransaction" }),
+            { error: { code: REJECTED } },
+        );
+        expect(err.message).toBe("Request failed");
+        expect(err.code).toBe(REJECTED);
+    });
+});
+
+// Every entry point the provider exposes, not just eth_requestAccounts. They
+// all funnel through the same response listener, and this is what says so.
+describe("every request path carries the code", () => {
+    const rejection = {
+        error: { code: REJECTED, message: "User rejected the request." },
+    };
+
+    test("request()", async () => {
+        const err = await rejectionFrom(
+            (p) => p.request({ method: "eth_requestAccounts" }),
+            rejection,
+        );
+        expect(err.code).toBe(REJECTED);
+    });
+
+    test("enable()", async () => {
+        const err = await rejectionFrom((p) => p.enable(), rejection);
+        expect(err.code).toBe(REJECTED);
+    });
+
+    test("send(method, params)", async () => {
+        const err = await rejectionFrom(
+            (p) => p.send("eth_requestAccounts", []),
+            rejection,
+        );
+        expect(err.code).toBe(REJECTED);
+    });
+
+    test("send({ method, params })", async () => {
+        const err = await rejectionFrom(
+            (p) => p.send({ method: "personal_sign", params: ["0x00"] }),
+            rejection,
+        );
+        expect(err.code).toBe(REJECTED);
+    });
+
+    test("sendAsync() hands the code to its callback", async () => {
+        const { provider, respond } = loadProvider();
+        const called = new Promise((resolve) => {
+            provider.sendAsync({ id: 1, method: "eth_requestAccounts" }, (e) =>
+                resolve(e),
+            );
+        });
+        respond(rejection);
+        const err = await called;
+        expect(err.name).toBe("ProviderRpcError");
+        expect(err.code).toBe(REJECTED);
+        expect(err.message).toBe("User rejected the request.");
+    });
+});
+
+describe("the success path is unchanged", () => {
+    test("a result still resolves", async () => {
+        const { provider, respond } = loadProvider();
+        const settled = provider.request({ method: "eth_requestAccounts" });
+        respond({ result: ["0xb61264DEFB0c4B8afb3D73724be15310036743a5"] });
+        await expect(settled).resolves.toEqual([
+            "0xb61264DEFB0c4B8afb3D73724be15310036743a5",
+        ]);
+        expect(provider.selectedAddress).toBe(
+            "0xb61264DEFB0c4B8afb3D73724be15310036743a5",
+        );
+    });
+});

tests/symbolSpoof.test.js

@@ -56,7 +56,7 @@ global.chrome = {
 };
 
 const { isSpoofedSymbol } = require("../src/shared/symbolSpoof");
-const { KNOWN_SYMBOLS } = require("../src/shared/tokenList");
+const { TOKENS, KNOWN_SYMBOLS } = require("../src/shared/tokenList");
 const { filterTransactions } = require("../src/shared/transactions");
 const {
     fetchTokenBalances,
@@ -124,6 +124,301 @@ describe("the shared rule", () => {
     });
 });
 
+// Issue #260: the symbol is whatever the ERC-20 contract returns, and HTML
+// collapses leading and trailing whitespace, so a token calling itself
+// `" ETH "` reaches the user's eye as `ETH` while missing a raw
+// KNOWN_SYMBOLS lookup.  Normalizing inside the shared rule fixes all three
+// surfaces at once, which is what consolidating the rule bought.
+//
+// Every character under test here is built from its code point rather than
+// pasted in: most of them are invisible, and an invisible character in a
+// test file is unreviewable.
+const cp = (...codes) => String.fromCodePoint(...codes);
+const NBSP = cp(0x00a0); // no-break space
+const FIGURE_SPACE = cp(0x2007);
+const IDEOGRAPHIC_SPACE = cp(0x3000);
+const ZWSP = cp(0x200b); // zero-width space
+const BOM = cp(0xfeff); // zero-width no-break space
+const WORD_JOINER = cp(0x2060);
+const SOFT_HYPHEN = cp(0x00ad);
+const LRM = cp(0x200e); // left-to-right mark
+const RLO = cp(0x202e); // right-to-left override
+const HANGUL_FILLER = cp(0x3164);
+const CHOSEONG_FILLER = cp(0x115f);
+const VS16 = cp(0xfe0f); // variation selector-16
+const VS1 = cp(0xfe00); // variation selector-1
+const NEL = cp(0x0085); // next line, a C1 control
+const DEL = cp(0x007f);
+const FULLWIDTH_ETH = cp(0xff25, 0xff34, 0xff28);
+const FULLWIDTH_USDC = cp(0xff55, 0xff53, 0xff44, 0xff43); // lowercase
+const CYRILLIC_CAPITAL_IE = cp(0x0415);
+
+describe("the shared rule: symbols that render as a known symbol", () => {
+    test("ASCII padding does not buy a pass", () => {
+        expect(isSpoofedSymbol(" ETH ", FAKE_ETH_CONTRACT)).toBe(true);
+        expect(isSpoofedSymbol("\tETH\n", FAKE_ETH_CONTRACT)).toBe(true);
+        expect(isSpoofedSymbol("  usdc  ", FAKE_ETH_CONTRACT)).toBe(true);
+    });
+
+    test("non-breaking and other Unicode spaces do not either", () => {
+        expect(isSpoofedSymbol(NBSP + "ETH" + NBSP, FAKE_ETH_CONTRACT)).toBe(
+            true,
+        );
+        expect(
+            isSpoofedSymbol(
+                FIGURE_SPACE + "ETH" + IDEOGRAPHIC_SPACE,
+                FAKE_ETH_CONTRACT,
+            ),
+        ).toBe(true);
+    });
+
+    // These render as nothing at all, in any position, so they are removed
+    // wherever they sit rather than only at the ends.
+    test("zero-width characters are stripped wherever they sit", () => {
+        expect(isSpoofedSymbol("E" + ZWSP + "TH", FAKE_ETH_CONTRACT)).toBe(
+            true,
+        );
+        expect(isSpoofedSymbol(BOM + "ETH", FAKE_ETH_CONTRACT)).toBe(true);
+        expect(
+            isSpoofedSymbol("ET" + WORD_JOINER + "H", FAKE_ETH_CONTRACT),
+        ).toBe(true);
+        expect(
+            isSpoofedSymbol("E" + SOFT_HYPHEN + "TH", FAKE_ETH_CONTRACT),
+        ).toBe(true);
+    });
+
+    // An LRM is invisible and, in all-Latin text, moves nothing: dropping it
+    // leaves exactly the string the user saw.
+    test("an invisible bidi mark does not hide a known symbol", () => {
+        expect(isSpoofedSymbol(LRM + "ETH", FAKE_ETH_CONTRACT)).toBe(true);
+    });
+
+    // Invisibility is not confined to \p{Cf}.  A Hangul filler is Lo and a
+    // variation selector is Mn, yet each of these four measures 32.00px in
+    // the repo's pinned e2e Chromium at 16px sans-serif — exactly the width
+    // of a plain `ETH` — so each reaches the user's eye as `ETH`.  They are
+    // caught by \p{Default_Ignorable_Code_Point}, not by \p{Cf}.
+    test("invisible non-format characters are stripped too", () => {
+        expect(isSpoofedSymbol(HANGUL_FILLER + "ETH", FAKE_ETH_CONTRACT)).toBe(
+            true,
+        );
+        expect(
+            isSpoofedSymbol(CHOSEONG_FILLER + "ETH", FAKE_ETH_CONTRACT),
+        ).toBe(true);
+        expect(isSpoofedSymbol("ETH" + VS16, FAKE_ETH_CONTRACT)).toBe(true);
+        expect(isSpoofedSymbol("E" + VS1 + "TH", FAKE_ETH_CONTRACT)).toBe(true);
+    });
+
+    // Nor is it confined to the Unicode classes.  U+007F is a control (Cc)
+    // and is not default-ignorable, so neither class reaches it, but it
+    // measures 32.00px in the same browser — it paints nothing, so a
+    // symbol carrying it reaches the eye as `ETH`.  It is named on its own
+    // in the strip for exactly that reason.
+    test("U+007F paints nothing and is stripped", () => {
+        expect(isSpoofedSymbol(DEL + "ETH", FAKE_ETH_CONTRACT)).toBe(true);
+    });
+
+    // The other side of the boundary, which is not the class boundary but
+    // the visibility one: the remaining C0 and C1 controls render as a
+    // visible 48.00px box in the same browser, so a symbol carrying one
+    // does not look like `ETH` and must not be judged a spoof.  Widening
+    // the strip to \p{Cc} — the obvious over-correction once U+007F is in
+    // it — fails this test.
+    test("visible control characters do not make a symbol a spoof", () => {
+        expect(isSpoofedSymbol(NEL + "ETH", FAKE_ETH_CONTRACT)).toBe(false);
+        expect(isSpoofedSymbol(cp(0x0001) + "ETH", FAKE_ETH_CONTRACT)).toBe(
+            false,
+        );
+        expect(isSpoofedSymbol(cp(0x0090) + "ETH", FAKE_ETH_CONTRACT)).toBe(
+            false,
+        );
+    });
+
+    test("compatibility forms fold onto the symbol they imitate", () => {
+        expect(isSpoofedSymbol(FULLWIDTH_ETH, FAKE_ETH_CONTRACT)).toBe(true);
+        expect(isSpoofedSymbol(FULLWIDTH_USDC, FAKE_ETH_CONTRACT)).toBe(true);
+    });
+
+    // The two knowingly open classes, asserted here so that the boundary is
+    // a fact in the suite and not a claim in a PR body.  A Cyrillic capital
+    // Ie is a distinct letter rather than a compatibility variant, so NFKC
+    // leaves it alone; and a right-to-left override reverses the rendering
+    // of what follows it, which dropping the control character does not
+    // undo.  Closing either needs a confusables table or a bidi resolver,
+    // and both are a separate change from this one.
+    test("a Cyrillic homoglyph is knowingly still not caught", () => {
+        expect(
+            isSpoofedSymbol(CYRILLIC_CAPITAL_IE + "TH", FAKE_ETH_CONTRACT),
+        ).toBe(false);
+    });
+
+    test("a bidi-reordered symbol is knowingly still not caught", () => {
+        expect(isSpoofedSymbol(RLO + "HTE", FAKE_ETH_CONTRACT)).toBe(false);
+    });
+
+    // Normalization does not reach the native-asset exemption, which turns
+    // on the absence of a contract address and never on the symbol.
+    test("a padded symbol with no contract is still not a spoof", () => {
+        expect(isSpoofedSymbol(" ETH ", null)).toBe(false);
+        expect(isSpoofedSymbol(NBSP + "ETH", "")).toBe(false);
+    });
+
+    test("a genuine contract still bears its own padded symbol", () => {
+        expect(isSpoofedSymbol(" USDC ", USDC_CONTRACT)).toBe(false);
+        expect(isSpoofedSymbol(ZWSP + "WETH", WETH_CONTRACT)).toBe(false);
+    });
+
+    // Normalization must not invent a match.  Interior ASCII whitespace is
+    // left alone: `E T H` renders as `E T H`, not as `ETH`, so folding it
+    // would filter a token no user could confuse with the native asset.
+    test("a symbol that renders differently is not judged a spoof", () => {
+        expect(isSpoofedSymbol("E T H", FAKE_ETH_CONTRACT)).toBe(false);
+        expect(isSpoofedSymbol("ETH2", FAKE_ETH_CONTRACT)).toBe(false);
+        expect(isSpoofedSymbol("MY ETH", FAKE_ETH_CONTRACT)).toBe(false);
+    });
+
+    // The false-positive question, answered against the shipped data rather
+    // than by assertion: no bundled symbol carries whitespace or a
+    // non-ASCII character, so the normalization cannot newly filter one.
+    // The character class starts at `!` rather than at the space so that it
+    // asserts the claim it stands for — `[ -~]` would admit an interior
+    // space and let a whitespace-bearing entry through the guard.
+    test("no bundled symbol is touched by the normalization", () => {
+        for (const [symbol, addresses] of KNOWN_SYMBOLS) {
+            expect(symbol).toBe(symbol.trim());
+            expect(symbol).toMatch(/^[!-~]+$/);
+            if (addresses === null) continue;
+            for (const address of addresses) {
+                expect(isSpoofedSymbol(symbol, address)).toBe(false);
+            }
+        }
+    });
+});
+
+// Issue #276: the guard that was missing.  The suite walked KNOWN_SYMBOLS,
+// which is built from TOKENS, so it could only ever assert that the table
+// agrees with itself.  Seven symbols appear twice in the bundled list at two
+// different real contracts, and the table kept whichever came first, so the
+// other seven contracts — tokens in our own shipped list, at their own
+// addresses — were judged spoofs and hidden from the balance list, the
+// history and the send selector.  That is the over-filtering direction: it
+// hides a holding the user cannot then spend.
+//
+// This walk is over TOKENS, the data the wallet actually ships, so it fails
+// whenever a bundled token would be filtered at its own address no matter
+// which side of the table the mistake is on.
+describe("the shipped token list", () => {
+    test("no bundled token is filtered at its own address", () => {
+        const filtered = TOKENS.filter((t) =>
+            isSpoofedSymbol(t.symbol, t.address),
+        ).map((t) => t.symbol + " @ " + t.address);
+        expect(filtered).toEqual([]);
+    });
+
+    // The third failure mode the issue asks about: a symbol whose table entry
+    // names an address that is in neither the table nor the list would be a
+    // contract we vouch for and do not ship.  There is none, and the table is
+    // built from the list, so this asserts the derivation has not acquired a
+    // hand-written entry.
+    test("every address the table vouches for is a bundled token", () => {
+        const bundled = new Set(TOKENS.map((t) => t.address.toLowerCase()));
+        for (const [symbol, addresses] of KNOWN_SYMBOLS) {
+            if (addresses === null) continue;
+            expect(addresses.size).toBeGreaterThan(0);
+            for (const address of addresses) {
+                expect(address).toBe(address.toLowerCase());
+                expect(bundled.has(address)).toBe(true);
+                // And it is the token that actually reports that symbol.
+                const token = TOKENS.find(
+                    (t) => t.address.toLowerCase() === address,
+                );
+                expect(token.symbol.toUpperCase()).toBe(symbol);
+            }
+        }
+    });
+
+    // Both contracts behind a shared ticker must pass, from either side: a
+    // rule that admits only the one the table happens to visit first is the
+    // bug, not the fix.
+    test("both contracts behind a shared ticker are admitted", () => {
+        const bySymbol = new Map();
+        for (const t of TOKENS) {
+            const upper = t.symbol.toUpperCase();
+            if (!bySymbol.has(upper)) bySymbol.set(upper, []);
+            bySymbol.get(upper).push(t);
+        }
+        const shared = [...bySymbol].filter(([, list]) => list.length > 1);
+        // The shared tickers are a fact about the shipped data; if a future
+        // list has none, this test would silently assert nothing.
+        expect(shared.length).toBeGreaterThan(0);
+        for (const [, list] of shared) {
+            for (const t of list) {
+                expect(isSpoofedSymbol(t.symbol, t.address)).toBe(false);
+            }
+        }
+    });
+
+    // The seven from issue #276, named so that the reconciliation is a fact
+    // in the suite: each is two real contracts from the same source fetch,
+    // and the table now holds both rather than the one that came first.
+    test("the seven shared tickers each name both bundled contracts", () => {
+        const expected = {
+            TON: [
+                "0x582d872a1b094fc48f5de31d3b73f2d9be47def1", // Toncoin
+                "0x2be5e8c109e2197d077d13a82daead6a9b3433c5", // Tokamak Network
+            ],
+            FRAX: [
+                "0x853d955acef822db058eb8505911ed77f175b99e", // Legacy Frax Dollar
+                "0x3432b6a60d23ca0dfca7761b7ab56459d9c964d0", // Frax (prev. FXS)
+            ],
+            REUSD: [
+                "0x5086bf358635b81d8c47c66d1c8b9e567db70c72", // Re Protocol reUSD
+                "0x57ab1e0003f623289cd798b1824be09a793e4bec", // Resupply USD
+            ],
+            EURE: [
+                "0x39b8b6385416f4ca36a20319f70d28621895279d", // Monerium EUR emoney
+                "0x3231cb76718cdef2155fc47b5286d82e6eda273f", // Monerium EUR emoney [OLD]
+            ],
+            MSUSD: [
+                "0x4ba01f22827018b4772cd326c7627fb4956a7c00", // Main Street USD
+                "0xab5eb14c09d416f0ac63661e57edb7aecdb9befa", // Metronome Synth USD
+            ],
+            MUSD: [
+                "0xaca92e438df0b2401ff60da7e4337b687a2435da", // MetaMask USD
+                "0xdd468a1ddc392dcdbef6db6e34e89aa338f9f186", // Mezo USD
+            ],
+            JPYC: [
+                "0x431d5dff03120afa4bdf332c61a6e1766ef37bdb", // JPY Coin
+                "0x2370f9d504c7a6e775bf6e14b3f12846b594cd53", // JPY Coin v1
+            ],
+        };
+        for (const [symbol, addresses] of Object.entries(expected)) {
+            expect([...KNOWN_SYMBOLS.get(symbol)].sort()).toEqual(
+                [...addresses].sort(),
+            );
+            for (const address of addresses) {
+                expect(isSpoofedSymbol(symbol, address)).toBe(false);
+            }
+        }
+    });
+
+    // The other direction, on the same symbols: widening the table to hold
+    // every bundled address for a ticker must not turn it into a pass for
+    // any other contract.
+    test("a shared ticker from a third contract is still a spoof", () => {
+        const bySymbol = new Map();
+        for (const t of TOKENS) {
+            const upper = t.symbol.toUpperCase();
+            if (!bySymbol.has(upper)) bySymbol.set(upper, []);
+            bySymbol.get(upper).push(t);
+        }
+        for (const [symbol, list] of bySymbol) {
+            if (list.length < 2) continue;
+            expect(isSpoofedSymbol(symbol, FAKE_ETH_CONTRACT)).toBe(true);
+        }
+    });
+});
+
 describe("surface 1: the transaction history", () => {
     function fakeEthTransfer() {
         return {
@@ -147,6 +442,22 @@ describe("surface 1: the transaction history", () => {
         expect(result.transactions).toEqual([]);
     });
 
+    // Issue #260 on this surface: the same transfer with a padded symbol.
+    test("a padded fake ETH token transfer is filtered too", () => {
+        const padded = { ...fakeEthTransfer(), symbol: " ETH " };
+        const result = filterTransactions([padded], {
+            hideSpoofedSymbols: true,
+            hideFraudContracts: true,
+            hideLowHolderTokens: true,
+            hideDustTransactions: true,
+            dustThresholdGwei: 100000,
+        });
+        expect(result.transactions).toEqual([]);
+        // The contract is learned as fraudulent, exactly as for the
+        // unpadded symbol: the padding must not cost the blocklist entry.
+        expect(result.newFraudContracts).toEqual([FAKE_ETH_CONTRACT]);
+    });
+
     test("a real native ETH transfer survives", () => {
         const native = {
             hash: "0x" + "2".repeat(64),
@@ -201,6 +512,36 @@ describe("surface 2: the Send token selector", () => {
         expect(select.children).toEqual([]);
     });
 
+    // Issue #260 on this surface: the option text is rendered into HTML,
+    // which collapses the padding, so an unfiltered padded token would sit
+    // in the selector reading exactly `ETH`.
+    test("a padded fake ETH token is not selectable either", () => {
+        render([
+            {
+                address: FAKE_ETH_CONTRACT,
+                symbol: " ETH ",
+                decimals: 18,
+                balance: "0.005",
+                holders: 900000,
+            },
+        ]);
+        expect(select.children).toEqual([]);
+    });
+
+    test("a genuine token with a padded symbol stays selectable", () => {
+        render([
+            {
+                address: USDC_CONTRACT,
+                symbol: " USDC ",
+                decimals: 6,
+                balance: "12.5",
+                holders: 900000,
+            },
+        ]);
+        expect(select.children).toHaveLength(1);
+        expect(select.children[0].value).toBe(USDC_CONTRACT);
+    });
+
     test("native ETH remains the always-present option", () => {
         render([]);
         expect(select.innerHTML).toBe('<option value="ETH">ETH</option>');
@@ -251,6 +592,35 @@ describe("surface 3: the balance list", () => {
         expect(balances).toEqual([]);
     });
 
+    // Issue #260 on this surface: the balance list is where the user forms
+    // 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, [])).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, [])).toEqual([]);
+    });
+
+    // The false-positive direction on the surface that matters most: a real
+    // holding whose symbol happens to carry padding is still listed, and the
+    // list still shows the symbol the token actually reports.
+    test("a genuine token with a padded symbol is not newly filtered", async () => {
+        respondWith([
+            fakeEthItem({
+                address_hash: USDC_CONTRACT,
+                symbol: " USDC ",
+                name: "USD Coin",
+                decimals: "6",
+            }),
+        ]);
+        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
+        expect(balances).toHaveLength(1);
+        expect(balances[0].symbol).toBe(" USDC ");
+    });
+
     test("a genuine token keeps its place in the list", async () => {
         respondWith([
             fakeEthItem({
@@ -274,6 +644,33 @@ describe("surface 3: the balance list", () => {
         expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, [])).toEqual([]);
     });
 
+    // The adjacent finding from the same review as issue #260: the type gate
+    // compared exactly, so an explorer that ever varied the casing would
+    // silently drop a real holding before any filter ran.  The comparison is
+    // now case-insensitive, which changes nothing about which types are
+    // admitted.
+    test("a differently-cased ERC-20 type still lists a real holding", async () => {
+        respondWith([
+            fakeEthItem({
+                type: "erc-20",
+                address_hash: USDC_CONTRACT,
+                symbol: "USDC",
+                name: "USD Coin",
+                decimals: "6",
+            }),
+        ]);
+        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, [])).toEqual([]);
+        respondWith([fakeEthItem({ type: "ERC-20-EXTRA" })]);
+        expect(await fetchTokenBalances(HOLDER, BLOCKSCOUT, [])).toEqual([]);
+    });
+
     // The money test: the user holds real ETH and has been airdropped a fake
     // ETH ERC-20.  The fake is gone from the list of tokens; the real balance
     // is exactly what the node reported.

tests/transactions.test.js

@@ -207,8 +207,8 @@ describe("token list assumptions the fixtures rely on", () => {
     });
 
     test("USDC and WETH map to their genuine lowercased contracts", () => {
-        expect(KNOWN_SYMBOLS.get("USDC")).toBe(USDC_CONTRACT);
+        expect([...KNOWN_SYMBOLS.get("USDC")]).toEqual([USDC_CONTRACT]);
-        expect(KNOWN_SYMBOLS.get("WETH")).toBe(WETH_CONTRACT);
+        expect([...KNOWN_SYMBOLS.get("WETH")]).toEqual([WETH_CONTRACT]);
     });
 
     test("the spam fixture symbol is not in the known token list", () => {