fix: a confirmation screen drawn again keeps the network it was reviewed for (closes #586)

ConfirmTx set the transaction's chain id to the active network's every
time it drew the screen, so a popup reopened onto a saved confirmation
after a network switch in Settings described the reviewed transfer as
the new network's and sent it there.

show() now sets the chain id only on a transaction Send hands over, and
the screen describes the transaction entirely on that network: native
currency, USD values, explorer links, and the node and explorer its
checks ask. explorerUrl(), renderAddressHtml(), getPrice(), formatFee()
and checkEtherscanLabel() take an optional chain id for this. A saved
transaction whose chain id names no network is not restored.

Model: opus-5-5

README.md

@@ -1013,10 +1013,12 @@ rendered differently on two screens.
 
 The native token's label is a network's `nativeCurrency` in
 `src/shared/networks.js`: `ETH` on mainnet, `SepoliaETH` on Sepolia. The
-wallet's balances and the Send and confirmation screens, which send on the
-active network, use the active network's. A transaction's figures use the one of
-the network its chain id names, whichever network is active: the value and fee
-on the approval screen, the amount on the wait, success and error screens, the
+wallet's balances and the Send screen, which sends on the active network, use
+the active network's. The confirmation screen uses the one of the network its
+transaction was reviewed on, the network active when Send showed it, even after
+the network is switched in Settings. A transaction's figures use the one of the
+network its chain id names, whichever network is active: the value and fee on
+the approval screen, the amount on the wait, success and error screens, the
 transaction history and the transaction detail screen, and the refusal of a fee
 above 1 ETH. A chain id that names no network reads `ETH`. Wherever this
 document shows ETH as the label of a native balance, value or fee, in a "Native
@@ -1195,9 +1197,10 @@ read:
 The swap's `Token In` and `Token Out` lines name a currency, not an amount; each
 reads `Unknown (not named in the calldata)` when the decoder found no token for
 that side, or `Unknown (could not be decoded)` instead when a V4 swap action in
-the transaction could not be read (see Transaction Decoding below). A V4 step
-with a swap action always sets the output side, and sets the input side only
-when no earlier step set it. It finds each side by three rules:
+the transaction could not be read or the transaction has an `EXECUTE_SUB_PLAN`
+step, which leaves both sides unknown (see Transaction Decoding below). A V4
+step with a swap action always sets the output side, and sets the input side
+only when no earlier step set it. It finds each side by three rules:
 
 1. Its input side is the currency its `SETTLE` or `SETTLE_ALL` names, or else
    the one currency that some swap action in the step spends and none buys. Its
@@ -1781,12 +1784,20 @@ view would leave a wallet one click from deletion.
       the contract's own answer is read at signing time only to be compared with
       it, and a disagreement is a refusal rather than a preference for either
       value (`src/shared/transferAmount.js`)
-    - "Sign & Send" after the active network was switched in Settings while this
-      screen was open → nothing is signed; "The active network changed after
+    - "Sign & Send" after the active network was switched in Settings since this
+      transaction was reviewed, with this screen open or before the popup
+      reopened onto it → nothing is signed; "The active network changed after
       this transaction was reviewed, so it was not sent. Please go back and
       review it again." in the errors box, no screen change. The transaction
-      carries the chain id of the network the screen was shown for, so it cannot
-      be signed for another
+      carries the chain id of the network active when Send showed this screen,
+      and keeps it when the screen is drawn again from the saved transaction, so
+      it cannot be signed for another. The screen describes it on that network,
+      whichever network is active: its amounts are in that network's native
+      currency, its USD values are that network's, so a testnet transaction
+      shows none, its From, To and token contract links open that network's
+      explorer, the fee estimate and the contract and never-sent recipient
+      checks ask that network's RPC endpoint, and the Etherscan label check asks
+      that network's explorer
     - "Sign & Send" (wrong password) → "Wrong password." on the password error
       line, no screen change
     - "Sign & Send" signs as the From address above, not as whichever address is
@@ -2892,7 +2903,18 @@ Currently supported:
   in the parameter shape deployed on mainnet and Sepolia, not in the newer one
   on `v4-periphery` `main`, which adds a `minHopPriceX36` field. An action in
   any other shape is not read, and its step is listed as
-  `V4 Swap (could not be decoded)`.
+  `V4 Swap (could not be decoded)`. Each step is named by its command type,
+  which the decoder reads from the command byte with the mask the router at that
+  address uses: `0x1f` for `UniversalRouterV1`, `0x3f` for
+  `UniversalRouterV1_2_V2Support` and `UniversalRouterV2`, and `0x7f` for
+  `UniversalRouterV2_1_1` and `UniversalRouterV2_1_2`. The allow-revert flag
+  (`0x80`) therefore does not change a step's name. The decoder does not read
+  the commands inside an `EXECUTE_SUB_PLAN` (`0x21`) step, and wherever that
+  step stands they may spend the user's tokens or pay the user. That step is
+  listed as `Execute Sub-Plan (its steps are not shown)`, and whatever the other
+  steps state, the summary names no swap direction, `Token In` and `Token Out`
+  read `Unknown (could not be decoded)`, and there is no `Amount` or
+  `Min. received` line.
 
 ### Non-Goals Forever
 

docs/README.md

@@ -306,7 +306,14 @@ enter your password and click "Confirm" to authorize it. Message and typed-data
 signature requests work the same way, with a "Sign" button, and also require
 your password.
 
-If the requesting site's domain is on the phishing blocklist, all three approval
+A connected site can also ask to switch the wallet's network. A popup shows the
+site's origin, the current network and the requested network. Nothing changes
+unless you click "Switch"; clicking "Reject" or closing the popup leaves
+everything as it was. Switching works exactly as it does in Settings, and
+changes the network for the whole wallet and for every site, not only for the
+one that asked.
+
+If the requesting site's domain is on the phishing blocklist, all four approval
 screens show a red phishing warning before you decide.
 
 You can manage site permissions in Settings. Allowed and denied sites can be
@@ -378,7 +385,8 @@ Click the gear icon on the home screen to access settings:
 - **Display**: Toggle whether tracked tokens with zero balance are shown, switch
   timestamps to UTC, and choose the theme (System, Light, or Dark).
 - **Network**: Switch between Ethereum Mainnet and Sepolia Testnet. Switching
-  resets the RPC and Blockscout endpoints to that network's defaults.
+  restores the RPC and Blockscout endpoints you last used on that network, or
+  that network's defaults if you have not used it before.
 - **Ethereum RPC**: Change the Ethereum node endpoint. Default is a public RPC.
   You can use your own node for maximum privacy.
 - **Blockscout API**: Change the Blockscout instance used for token balances and

src/popup/viewRouter.js

@@ -13,6 +13,7 @@
 // cannot be required outside a browser.
 
 const { RESTORABLE_VIEWS } = require("../shared/restorableViews");
+const { SUPPORTED_CHAIN_IDS } = require("../shared/networks");
 
 // The views this page load has rendered.
 //
@@ -125,13 +126,16 @@ function isRenderableDecoded(value) {
 
 // The pending transaction confirmTx.show() renders: `token` reaches
 // renderAddressHtml() when it is not "ETH", and `from`/`to` reach
-// addressTitle(), makeBlockie() and getLocalWarnings().
+// addressTitle(), makeBlockie() and getLocalWarnings(). `chainId`, which
+// show() fills in when it is absent, picks the network whose explorer the
+// address links open, so it has to name one.
 function isRenderablePendingTx(value) {
     return (
         isRecord(value) &&
         isText(value.token) &&
         isAddressText(value.from) &&
-        isAddressText(value.to)
+        isAddressText(value.to) &&
+        (!value.chainId || SUPPORTED_CHAIN_IDS.has(value.chainId))
     );
 }
 

src/popup/views/confirmTx.js

@@ -11,7 +11,6 @@ const {
     addressTitle,
     escapeHtml,
     displaySymbol,
-    nativeCurrency,
     renderAddressHtml,
     blockieHtml,
     attachCopyHandlers,
@@ -20,6 +19,10 @@ const {
     formatFee,
 } = require("./helpers");
 const { state, currentNetwork } = require("../../shared/state");
+const {
+    networkByChainId,
+    nativeCurrencyByChainId,
+} = require("../../shared/networks");
 const { getSignerForAddress } = require("../../shared/wallet");
 const { walletDefect } = require("../../shared/walletDefects");
 const { decryptWithPassword } = require("../../shared/vault");
@@ -68,11 +71,11 @@ function restore() {
     }
 }
 
-function confirmAddressHtml(address, ensName, title) {
+function confirmAddressHtml(address, ensName, title, chainId) {
     const blockie = blockieHtml(address);
     return (
         `<div class="mb-1">${blockie}</div>` +
-        renderAddressHtml(address, { title, ensName })
+        renderAddressHtml(address, { title, ensName, chainId })
     );
 }
 
@@ -87,8 +90,10 @@ function valueWithUsd(text, usdAmount) {
 // once its amount is re-derived from the fee estimate.
 function renderAmount(txInfo) {
     const isErc20 = txInfo.token !== "ETH";
-    const rawSymbol = isErc20 ? txInfo.tokenSymbol || "?" : nativeCurrency();
-    const price = isErc20 ? getPrice(rawSymbol) : getPrice("ETH");
+    const rawSymbol = isErc20
+        ? txInfo.tokenSymbol || "?"
+        : nativeCurrencyByChainId(txInfo.chainId);
+    const price = getPrice(isErc20 ? rawSymbol : "ETH", txInfo.chainId);
     const amountUsd = price ? parseFloat(txInfo.amount) * price : null;
     $("confirm-amount").textContent = valueWithUsd(
         txInfo.amount + " " + displaySymbol(rawSymbol),
@@ -101,16 +106,22 @@ function show(txInfo) {
     feeStatus = FEE_PENDING;
     feeWei = null;
     maxSendFees = null;
-    // The network this screen is drawn for, and the only one it sends on:
-    // Settings can switch the active network while the screen is open. The
-    // wait, success and error screens label the amount by it too.
-    txInfo.chainId = currentNetwork().chainId;
+    // The network this screen is drawn for, and the only one it sends on: the
+    // one active when Send handed the transaction over. Drawn again from the
+    // saved transaction, as when the popup reopens onto this screen, it keeps
+    // that network, so Sign & Send refuses once Settings has switched to
+    // another. Everything this screen shows is that network's: native
+    // currency, USD values, explorer links, and the node and explorer its
+    // checks ask. The wait, success and error screens label amounts by it.
+    if (!txInfo.chainId) txInfo.chainId = currentNetwork().chainId;
 
     const isErc20 = txInfo.token !== "ETH";
     // The raw symbol is the price-table key; the capped one is what the
     // screen says. Truncating before the lookup would silently drop the
     // price of any token whose symbol is long enough to be capped.
-    const rawSymbol = isErc20 ? txInfo.tokenSymbol || "?" : nativeCurrency();
+    const rawSymbol = isErc20
+        ? txInfo.tokenSymbol || "?"
+        : nativeCurrencyByChainId(txInfo.chainId);
     const symbol = displaySymbol(rawSymbol);
 
     // Transaction type
@@ -126,7 +137,7 @@ function show(txInfo) {
     if (isErc20) {
         $("confirm-token-contract").innerHTML = renderAddressHtml(
             txInfo.token,
-            {},
+            { chainId: txInfo.chainId },
         );
         tokenSection.classList.remove("hidden");
         attachCopyHandlers(tokenSection);
@@ -140,6 +151,7 @@ function show(txInfo) {
         txInfo.from,
         null,
         fromTitle,
+        txInfo.chainId,
     );
 
     // To (with blockie)
@@ -148,14 +160,15 @@ function show(txInfo) {
         txInfo.to,
         txInfo.ensName,
         toTitle,
+        txInfo.chainId,
     );
     $("confirm-to-ens").classList.add("hidden");
 
     renderAmount(txInfo);
 
     // Balance (with inline USD)
-    const ethPrice = getPrice("ETH");
-    const tokenPrice = getPrice(rawSymbol);
+    const ethPrice = getPrice("ETH", txInfo.chainId);
+    const tokenPrice = getPrice(rawSymbol, txInfo.chainId);
     if (isErc20) {
         // null is a balance whose scale nothing knows, not a balance of zero
         // (https://git.eeqj.de/sneak/AutistMask/issues/349). The send is
@@ -212,9 +225,9 @@ function show(txInfo) {
     $("confirm-gas-error").classList.toggle("hidden", !isErc20);
     $("confirm-gas-error").textContent =
         "You do not have enough " +
-        nativeCurrency() +
+        nativeCurrencyByChainId(txInfo.chainId) +
         " to pay the network fee for this transfer. Please add " +
-        nativeCurrency() +
+        nativeCurrencyByChainId(txInfo.chainId) +
         " to this address and try again.";
 
     // Both shown later, by checkRecipientHistory(). The first sentence says
@@ -222,12 +235,12 @@ function show(txInfo) {
     $("confirm-recipient-warning").textContent =
         "WARNING: The recipient address has never sent a transaction and" +
         " holds no " +
-        nativeCurrency() +
+        nativeCurrencyByChainId(txInfo.chainId) +
         ". This may indicate a fresh or unused address. Double-check the" +
         " address before sending.";
     $("confirm-contract-warning").textContent =
         "WARNING: The recipient is a smart contract. Sending " +
-        nativeCurrency() +
+        nativeCurrencyByChainId(txInfo.chainId) +
         " or tokens directly to a contract may result in permanent loss of" +
         " funds.";
 
@@ -280,7 +293,7 @@ function renderValidation(txInfo) {
     const isErc20 = txInfo.token !== "ETH";
     const symbol = isErc20
         ? displaySymbol(txInfo.tokenSymbol || "?")
-        : nativeCurrency();
+        : nativeCurrencyByChainId(txInfo.chainId);
 
     const { canSend, codes } = validateTransfer({
         isErc20,
@@ -369,9 +382,23 @@ function setVisible(id, visible) {
     $(id).style.visibility = visible ? "visible" : "hidden";
 }
 
+// The node of the network this transaction was reviewed for, which need not be
+// the active one: the popup can reopen onto this screen after Settings switched
+// the network. Its RPC URL is the one Settings has for that network: the
+// active network's is state.rpcUrl, any other's the one remembered for it (see
+// applyChainSwitchFields()).
+function reviewedNetworkProvider(txInfo) {
+    const net = networkByChainId(txInfo.chainId);
+    if (net.id === state.networkId) {
+        return getProvider(state.rpcUrl, net.id);
+    }
+    const remembered = state.networkEndpoints[net.id] || {};
+    return getProvider(remembered.rpcUrl || net.defaultRpcUrl, net.id);
+}
+
 async function estimateGas(txInfo) {
     try {
-        const provider = getProvider(state.rpcUrl, state.networkId);
+        const provider = reviewedNetworkProvider(txInfo);
         const feeData = await provider.getFeeData();
         let gasLimit;
 
@@ -419,12 +446,17 @@ async function estimateGas(txInfo) {
         // does, so the same fee reads the same on both.
         if (estimateWei !== null && estimateWei < gasCostWei) {
             $("confirm-fee-amount").textContent =
-                "~" + formatFee(estimateWei, nativeCurrency());
+                "~" +
+                formatFee(
+                    estimateWei,
+                    nativeCurrencyByChainId(txInfo.chainId),
+                    txInfo.chainId,
+                );
             $("confirm-fee-reserve").textContent =
                 "up to " +
                 truncateAmountNeverZero(formatEther(gasCostWei)) +
                 " " +
-                nativeCurrency() +
+                nativeCurrencyByChainId(txInfo.chainId) +
                 " reserved";
             setVisible("confirm-fee-reserve", true);
         } else {
@@ -433,7 +465,8 @@ async function estimateGas(txInfo) {
             // cost is not below the reserve. Show the reserve alone.
             $("confirm-fee-amount").textContent = formatFee(
                 gasCostWei,
-                nativeCurrency(),
+                nativeCurrencyByChainId(txInfo.chainId),
+                txInfo.chainId,
             );
             setVisible("confirm-fee-reserve", false);
         }
@@ -523,9 +556,10 @@ function showSendError(message) {
 
 async function checkRecipientHistory(txInfo) {
     try {
-        const provider = getProvider(state.rpcUrl, state.networkId);
+        const provider = reviewedNetworkProvider(txInfo);
         const asyncWarnings = await getFullWarnings(txInfo.to, provider, {
             fromAddress: txInfo.from,
+            chainId: txInfo.chainId,
         });
         for (const w of asyncWarnings) {
             if (w.type === "contract") {
@@ -564,8 +598,10 @@ function init(_ctx) {
             return;
         }
 
-        // Back from Settings only unhides this screen, still drawn for the
-        // network that was active when it was shown.
+        // The screen describes the network the transaction was reviewed for,
+        // which Settings may have switched away from since: with this screen
+        // open, where Back only unhides it, or before the popup reopened onto
+        // it.
         if (currentNetwork().chainId !== pendingTx.chainId) {
             showSendError(
                 "The active network changed after this transaction was" +

src/popup/views/helpers.js

@@ -22,6 +22,7 @@ const { resolveTokenSymbol } = require("../../shared/approvalAmount");
 const { DEBUG } = require("../../shared/constants");
 const { escapeHtml } = require("../../shared/html");
 const { isDebug } = require("../../shared/log");
+const { networkByChainId } = require("../../shared/networks");
 const { formatUsd, getPrice } = require("../../shared/prices");
 const { state, saveState, currentNetwork } = require("../../shared/state");
 const { displaySymbol } = require("../../shared/symbolDisplay");
@@ -284,11 +285,12 @@ function unknownableAmount(balance) {
 
 // The active network's native token symbol, `ETH` on mainnet and `SepoliaETH`
 // on Sepolia, as src/shared/networks.js names it. The wallet's balances and
-// the Send and confirmation screens, which send on the active network, label a
-// native amount with this; a transaction already made or requested is labelled
-// by its own chain id, through nativeCurrencyByChainId() in networks.js. The
-// "ETH" that state.selectedToken and txInfo.token hold is the native token's
-// id, not its label, and stays "ETH" on every network.
+// the Send screen, which sends on the active network, label a native amount
+// with this; the confirmation screen, and a transaction already made or
+// requested, label it by the transaction's own chain id, through
+// nativeCurrencyByChainId() in networks.js. The "ETH" that state.selectedToken
+// and txInfo.token hold is the native token's id, not its label, and stays
+// "ETH" on every network.
 function nativeCurrency() {
     return currentNetwork().nativeCurrency;
 }
@@ -307,11 +309,12 @@ function tokenLabel(address) {
 // A network fee in wei as the confirmation and approval screens both show it:
 // the ETH figure through truncateAmountNeverZero() and labelled `symbol`, the
 // native currency of the network the fee is paid on, then its USD value when
-// the ETH price is known. The USD value is of the exact fee, not of the
-// truncated figure.
-function formatFee(wei, symbol) {
+// the ETH price is known on the network with `chainId`, or on the active
+// network when no chain id is given. The USD value is of the exact fee, not of
+// the truncated figure.
+function formatFee(wei, symbol, chainId) {
     const eth = formatEther(wei);
-    const ethPrice = getPrice("ETH");
+    const ethPrice = getPrice("ETH", chainId);
     const usd = ethPrice ? formatUsd(parseFloat(eth) * ethPrice) : "";
     return (
         truncateAmountNeverZero(eth) +
@@ -604,17 +607,19 @@ const EXT_ICON =
     `</svg></span>`;
 
 // Block-explorer URLs. The origin is a per-network constant from
-// src/shared/networks.js; only the path segment is data, and it comes out
-// of explorer JSON (a transaction's from/to, a token's address_hash), which
-// nothing upstream validates as hex. percent-encoding it keeps a segment
-// that contains a slash, a query or a fragment from re-pointing the link
-// somewhere else in the explorer.
-function explorerUrl(kind, value) {
-    return `${currentNetwork().explorerUrl}/${kind}/${encodeURIComponent(value)}`;
+// src/shared/networks.js, the explorer of the network with `chainId`, or of
+// the active network when no chain id is given; only the path segment is
+// data, and it comes out of explorer JSON (a transaction's from/to, a token's
+// address_hash), which nothing upstream validates as hex. percent-encoding it
+// keeps a segment that contains a slash, a query or a fragment from
+// re-pointing the link somewhere else in the explorer.
+function explorerUrl(kind, value, chainId) {
+    const network = chainId ? networkByChainId(chainId) : currentNetwork();
+    return `${network.explorerUrl}/${kind}/${encodeURIComponent(value)}`;
 }
 
-function etherscanAddressUrl(address) {
-    return explorerUrl("address", address);
+function etherscanAddressUrl(address, chainId) {
+    return explorerUrl("address", address, chainId);
 }
 
 // The URL still has to be escaped on the way into href="...": encoding
@@ -680,16 +685,18 @@ function attachCopyHandlers(container) {
 //              with them, and the "at least 32 characters" guarantee has
 //              to survive having no current callers to be a guarantee.
 //   noLink   — if true, omit etherscan link
+//   chainId  — the network whose explorer the link opens; the active
+//              network's when absent
 //
 // After inserting the returned HTML into the DOM, call
 // attachCopyHandlers() on the parent to wire up click-to-copy.
 function renderAddressHtml(address, opts) {
-    const { title, ensName, maxLen, noLink } = opts || {};
+    const { title, ensName, maxLen, noLink, chainId } = opts || {};
     const dot = addressDotHtml(address);
     const displayAddr = maxLen
         ? truncateMiddle(address, Math.max(ADDRESS_MIN_DISPLAY_LEN, maxLen))
         : address;
-    const link = etherscanAddressUrl(address);
+    const link = etherscanAddressUrl(address, chainId);
     const extLink = noLink ? "" : etherscanLinkHtml(link);
 
     let html = "";

src/shared/addressWarnings.js

@@ -58,6 +58,8 @@ function getLocalWarnings(address, options = {}) {
  * @param {object} provider - An ethers.js provider instance.
  * @param {object} [options] - Optional context.
  * @param {string} [options.fromAddress] - Sender address (for self-send check).
+ * @param {string} [options.chainId] - Chain id of the network whose explorer
+ *   the Etherscan label check asks; the active network's when omitted.
  * @returns {Promise<Array<{type: string, message: string, severity: string}>>}
  */
 async function getFullWarnings(address, provider, options = {}) {
@@ -110,7 +112,10 @@ async function getFullWarnings(address, provider, options = {}) {
     // Runs for ALL addresses including contracts, since many dangerous
     // flagged addresses on Etherscan (drainers, phishing contracts) are contracts.
     try {
-        const etherscanWarning = await checkEtherscanLabel(address);
+        const etherscanWarning = await checkEtherscanLabel(
+            address,
+            options.chainId,
+        );
         if (etherscanWarning) {
             warnings.push(etherscanWarning);
         }

src/shared/etherscanLabels.js

@@ -2,6 +2,8 @@
 // Extension users make the requests directly to Etherscan — no proxy needed.
 // This is a best-effort enrichment: network failures return null silently.
 
+const { networkByChainId } = require("./networks");
+
 // Patterns in the page title that indicate a flagged address.
 // Title format: "Fake_Phishing184810 | Address: 0x... | Etherscan"
 const PHISHING_LABEL_PATTERNS = [/^Fake_Phishing/i, /^Phish:/i, /^Exploiter/i];
@@ -72,18 +74,21 @@ function parseEtherscanPage(html) {
  * Returns a warning object if the address is flagged, or null.
  * Network failures return null silently (best-effort check).
  *
- * Uses the current network's explorer URL so the lookup works on both
- * mainnet (etherscan.io) and Sepolia (sepolia.etherscan.io).
+ * Uses the explorer of the network with `chainId`, or of the active network
+ * when it is omitted: etherscan.io on mainnet, sepolia.etherscan.io on
+ * Sepolia.
  *
  * @param {string} address - Ethereum address to check.
+ * @param {string} [chainId] - Chain id of the network to look it up on.
  * @returns {Promise<{type: string, message: string, severity: string}|null>}
  */
-async function checkEtherscanLabel(address) {
+async function checkEtherscanLabel(address, chainId) {
     try {
         // Lazy require to avoid pulling in chrome.storage at module scope
         // (which breaks unit tests that only exercise parseEtherscanPage).
         const { currentNetwork } = require("./state");
-        const etherscanBase = currentNetwork().explorerUrl + "/address/";
+        const network = chainId ? networkByChainId(chainId) : currentNetwork();
+        const etherscanBase = network.explorerUrl + "/address/";
         const resp = await fetch(etherscanBase + address, {
             headers: { Accept: "text/html" },
         });

src/shared/prices.js

@@ -2,6 +2,7 @@
 
 const { getTopTokenPrices } = require("./tokenList");
 const { isBelowOneMillionth } = require("./amountDisplay");
+const { networkByChainId } = require("./networks");
 
 const PRICE_CACHE_TTL = 300000; // 5 minutes
 
@@ -36,10 +37,12 @@ function clearPrices() {
     lastFetchedAt = 0;
 }
 
-// Return the USD price for a symbol, or null on testnet / unknown.
-function getPrice(symbol) {
+// Return the USD price for a symbol on the network with `chainId`, or on the
+// active network when no chain id is given; null on testnet / unknown.
+function getPrice(symbol, chainId) {
     const { currentNetwork } = require("./state");
-    if (currentNetwork().isTestnet) return null;
+    const network = chainId ? networkByChainId(chainId) : currentNetwork();
+    if (network.isTestnet) return null;
     return prices[symbol] || null;
 }
 

src/shared/uniswap.js

@@ -19,39 +19,54 @@ const ROUTER_IFACE = new Interface([
 // The Universal Router deployments on each network, by chain id, copied from
 // the deployment files Uniswap publishes, each address named by its key there.
 // The files also list `UnsupportedProtocol`, which is not a router.
+//
+// Beside each address is the mask that router reads a command's type with:
+// its dispatcher runs `commandType & Commands.COMMAND_TYPE_MASK`, and the bits
+// above the mask are the allow-revert flag (0x80) or ignored. The mask grew
+// between releases. Each is `COMMAND_TYPE_MASK` in the release's
+// `contracts/libraries/Commands.sol`, the same file as in the source verified
+// for that address:
+// - 0x1f, UniversalRouterV1: https://github.com/Uniswap/universal-router/blob/cda697da221e24ca143bc4f55023694a2a16796f/contracts/libraries/Commands.sol
+// - 0x3f, UniversalRouterV1_2_V2Support: https://github.com/Uniswap/universal-router/blob/41183d6eb154f0ab0e74a0e911a5ef9ea51fc4bd/contracts/libraries/Commands.sol
+// - 0x3f, UniversalRouterV2: https://github.com/Uniswap/universal-router/blob/3663f6db6e2fe121753cd2d899699c2dc75dca86/contracts/libraries/Commands.sol
+// - 0x7f, UniversalRouterV2_1_1: https://github.com/Uniswap/universal-router/blob/999d561c3ad58fb5cab91b602911f3c75591a9c7/contracts/libraries/Commands.sol
+// - 0x7f, UniversalRouterV2_1_2: https://github.com/Uniswap/universal-router/blob/802fe4c18f47300e0f183e2a42e9146ec2ea9fc3/contracts/libraries/Commands.sol
 const ROUTER_ADDRESSES = new Map([
     [
         NETWORKS.mainnet.chainId,
         // https://github.com/Uniswap/universal-router/blob/543e1a19d6e21e31ced2512eec5792b50f13a0ba/deploy-addresses/mainnet.json
         [
-            "0xEf1c6E67703c7BD7107eed8303Fbe6EC2554BF6B", // UniversalRouterV1
-            "0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD", // UniversalRouterV1_2_V2Support
-            "0x66a9893cc07d91d95644aedd05d03f95e1dba8af", // UniversalRouterV2
-            "0x4C82D1fBFe28C977cBB58D8C7FF8FCF9F70a2cCA", // UniversalRouterV2_1_1
-            "0x23617e59A5925b2A4Bf75d73ff6711cD0b29De85", // UniversalRouterV2_1_2
+            ["0xEf1c6E67703c7BD7107eed8303Fbe6EC2554BF6B", 0x1f], // UniversalRouterV1
+            ["0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD", 0x3f], // UniversalRouterV1_2_V2Support
+            ["0x66a9893cc07d91d95644aedd05d03f95e1dba8af", 0x3f], // UniversalRouterV2
+            ["0x4C82D1fBFe28C977cBB58D8C7FF8FCF9F70a2cCA", 0x7f], // UniversalRouterV2_1_1
+            ["0x23617e59A5925b2A4Bf75d73ff6711cD0b29De85", 0x7f], // UniversalRouterV2_1_2
         ],
     ],
     [
         NETWORKS.sepolia.chainId,
         // https://github.com/Uniswap/universal-router/blob/543e1a19d6e21e31ced2512eec5792b50f13a0ba/deploy-addresses/sepolia.json
         [
-            "0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD", // UniversalRouterV1_2_V2Support
-            "0x3a9d48ab9751398bbfa63ad67599bb04e4bdf98b", // UniversalRouterV2
-            "0x7DfD4F31be6814D2906BDE155c3e1B146EAc1468", // UniversalRouterV2_1_1
-            "0x7E4f6c5e954Da5c61B3423D81E2277431Ac043f3", // UniversalRouterV2_1_2
+            ["0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD", 0x3f], // UniversalRouterV1_2_V2Support
+            ["0x3a9d48ab9751398bbfa63ad67599bb04e4bdf98b", 0x3f], // UniversalRouterV2
+            ["0x7DfD4F31be6814D2906BDE155c3e1B146EAc1468", 0x7f], // UniversalRouterV2_1_1
+            ["0x7E4f6c5e954Da5c61B3423D81E2277431Ac043f3", 0x7f], // UniversalRouterV2_1_2
         ],
     ],
 ]);
 
-// Whether `address` is a Universal Router deployment on the network with this
-// chain id. Address case is ignored.
-function isRouterAddress(address, chainId) {
+// The mask the Universal Router deployment at `address` on the network with
+// this chain id reads a command's type with, or null when `address` is not one
+// of them. Address case is ignored.
+function routerCommandTypeMask(address, chainId) {
     const routers = ROUTER_ADDRESSES.get(chainId) || [];
     const wanted = (address || "").toLowerCase();
-    return routers.some((router) => router.toLowerCase() === wanted);
+    const router = routers.find(([a]) => a.toLowerCase() === wanted);
+    return router ? router[1] : null;
 }
 
-// Universal Router command IDs (lower 5 bits of each command byte)
+// Universal Router command types, each read from its command byte with the
+// router's mask (see ROUTER_ADDRESSES)
 const COMMAND_NAMES = {
     0x00: "V3 Swap (Exact In)",
     0x01: "V3 Swap (Exact Out)",
@@ -90,8 +105,10 @@ function formatAmount(raw, decimals) {
 const UNNAMED_CURRENCY = "Unknown (not named in the calldata)";
 
 // The same refusal when a V4 swap action could not be read (see
-// decodeExactly()). That action names both of its currencies, so saying the
-// calldata did not name one would be false.
+// decodeExactly()), or the transaction has an EXECUTE_SUB_PLAN step, whose
+// commands this decoder does not read. That action names both of its
+// currencies, and those commands may name one, so saying the calldata did not
+// name it would be false.
 const UNDECODED_CURRENCY = "Unknown (could not be decoded)";
 
 // Explicit presence, never truthiness. Every gate in this file that guards a
@@ -603,7 +620,8 @@ function decodeV4Swap(input) {
 // sent to any other contract is not a swap through the router, whatever that
 // contract does with it.
 function decode(data, toAddress, chainId, sources) {
-    if (!isRouterAddress(toAddress, chainId)) return null;
+    const commandTypeMask = routerCommandTypeMask(toAddress, chainId);
+    if (commandTypeMask === null) return null;
     try {
         const parsed = ROUTER_IFACE.parseTransaction({ data });
         if (!parsed) return null;
@@ -621,6 +639,7 @@ function decode(data, toAddress, chainId, sources) {
         let hasUnwrapWeth = false;
         let hasV2ExactOut = false;
         let swapUndecoded = false;
+        let hasSubPlan = false;
         const commandNames = [];
 
         // THE INVARIANT: an amount and the token it is counted in always come
@@ -660,13 +679,21 @@ function decode(data, toAddress, chainId, sources) {
         };
 
         for (let i = 0; i < commandsBytes.length; i++) {
-            const cmdId = commandsBytes[i] & 0x1f;
+            const cmdId = commandsBytes[i] & commandTypeMask;
             commandNames.push(
                 COMMAND_NAMES[cmdId] ||
                     "Command 0x" + cmdId.toString(16).padStart(2, "0"),
             );
 
             try {
+                if (cmdId === 0x21) {
+                    // EXECUTE_SUB_PLAN runs a further list of commands held in
+                    // its input, which this decoder does not read. The step
+                    // says so, and after this loop neither side is named.
+                    hasSubPlan = true;
+                    commandNames[i] += " (its steps are not shown)";
+                }
+
                 if (cmdId === 0x0a) {
                     const p = decodePermit2(inputs[i]);
                     // A permit states both halves itself, so it may replace an
@@ -767,14 +794,28 @@ function decode(data, toAddress, chainId, sources) {
             }
         }
 
+        // The commands of an EXECUTE_SUB_PLAN step may spend the user's tokens
+        // or pay the user, before or after any other step, and a permit among
+        // them would replace the input side. What the other steps state is
+        // then not the whole swap, so both sides are set unknown, with no
+        // figure, wherever the step stands.
+        if (hasSubPlan) {
+            inputToken = null;
+            inputAmount = null;
+            outputToken = null;
+            minOutput = null;
+            outputEstablished = true;
+        }
+
         // Resolve token info. A null token on either side means no step named
-        // a currency for it, or a V4 step with a swap action left it
-        // unknown; tokenInfo() refuses rather than calling it ETH.
-        // UNWRAP_WETH turns WETH into ETH, so it makes the output ETH when the
-        // output side is WETH, or when no step set the output side. A V4 step
-        // with a swap action did set it, even when it set it unknown. Any other
-        // output keeps its own token and figure: a swap that buys USDC and
-        // then unwraps the WETH it did not spend receives USDC.
+        // a currency for it, a V4 step with a swap action left it unknown, or
+        // an EXECUTE_SUB_PLAN step did; tokenInfo() refuses rather than calling
+        // it ETH. UNWRAP_WETH turns WETH into ETH, so it makes the output ETH
+        // when the output side is WETH, or when no step set the output side. A
+        // V4 step with a swap action, or an EXECUTE_SUB_PLAN step, did set it,
+        // even when it set it unknown. Any other output keeps its own token
+        // and figure: a swap that buys USDC and then unwraps the WETH it did
+        // not spend receives USDC.
         const outputIsWeth =
             present(outputToken) &&
             WETH_ADDRESSES.includes(outputToken.toLowerCase());
@@ -819,7 +860,10 @@ function decode(data, toAddress, chainId, sources) {
             // screen must not describe the same condition in two ways.
             details.push({
                 label: "Token In",
-                value: swapUndecoded ? UNDECODED_CURRENCY : UNNAMED_CURRENCY,
+                value:
+                    swapUndecoded || hasSubPlan
+                        ? UNDECODED_CURRENCY
+                        : UNNAMED_CURRENCY,
             });
         }
 
@@ -885,7 +929,10 @@ function decode(data, toAddress, chainId, sources) {
             // calldata did not state.
             details.push({
                 label: "Token Out",
-                value: swapUndecoded ? UNDECODED_CURRENCY : UNNAMED_CURRENCY,
+                value:
+                    swapUndecoded || hasSubPlan
+                        ? UNDECODED_CURRENCY
+                        : UNNAMED_CURRENCY,
             });
         }
 

tests/confirmTxNetworkSwitch.test.js

@@ -7,25 +7,52 @@
 // reviewed on Sepolia went out as 1 ETH on mainnet once mainnet was chosen in
 // Settings in between.
 //
+// The same holds when the popup was closed after the switch and reopened, and
+// Back drew the screen again from the transaction it saved
+// (https://git.eeqj.de/sneak/AutistMask/issues/586): the screen was drawn for
+// the new network, and Sign & Send sent the reviewed transfer there. Drawn
+// again, the screen describes the transaction entirely on the network it was
+// reviewed for, because choosing that network again in Settings and pressing
+// Back only unhides it, and Sign & Send then sends from it.
+//
 // Driven through the real confirmation screen, signer and chain switch, with
-// only the node and the DOM stubbed. The stub node is on the network its
-// provider was built for, so a broadcast records the network it went to.
+// only the node, fetch and the DOM stubbed. The stub node is on the network
+// its provider was built for, so a broadcast records the network it went to.
 
 "use strict";
 
-// The signed transactions the stub node was handed, with its network's chain id.
-const mockNode = { broadcast: [] };
+// The questions the stub node was asked for the fee and the recipient checks,
+// by method, network name and RPC URL, in order. The signed transactions it
+// was handed, with its network's chain id and RPC URL. And whether it quotes
+// fees as a network with no type-2 pricing does.
+const mockNode = { asked: [], broadcast: [], legacyFees: false };
 
 jest.mock("ethers", () => {
     const actual = jest.requireActual("ethers");
     class StubProvider {
         constructor(url, network) {
+            this.url = url;
             this.network = network;
         }
+        record(method) {
+            mockNode.asked.push({
+                method,
+                network: this.network.name,
+                url: this.url,
+            });
+        }
         async getNetwork() {
             return this.network;
         }
         async getFeeData() {
+            this.record("getFeeData");
+            if (mockNode.legacyFees) {
+                return {
+                    maxFeePerGas: null,
+                    maxPriorityFeePerGas: null,
+                    gasPrice: 10000000000n,
+                };
+            }
             return {
                 maxFeePerGas: 20000000000n,
                 maxPriorityFeePerGas: 1000000000n,
@@ -36,16 +63,22 @@ jest.mock("ethers", () => {
             return 21000n;
         }
         async getCode() {
+            this.record("getCode");
             return "0x";
         }
         async getTransactionCount() {
+            this.record("getTransactionCount");
             return 1;
         }
         async lookupAddress() {
             return null;
         }
         async broadcastTransaction(signed) {
-            mockNode.broadcast.push({ chainId: this.network.chainId, signed });
+            mockNode.broadcast.push({
+                chainId: this.network.chainId,
+                url: this.url,
+                signed,
+            });
             return { hash: "0x" + "ab".repeat(32) };
         }
     }
@@ -75,6 +108,8 @@ jest.mock("../src/popup/views/txStatus", () => ({
     showError: jest.fn(),
 }));
 
+// The Etherscan label check is its only caller here: the explorer pages it
+// asks for are recorded, and nothing is fetched.
 global.fetch = jest.fn(() => {
     throw new Error("tests must not perform network requests");
 });
@@ -125,15 +160,27 @@ global.navigator = { clipboard: { writeText() {} } };
 
 const { BaseWallet, Transaction, Wallet } = require("ethers");
 const { encryptWithPassword } = require("../src/shared/vault");
-const { state, loadState } = require("../src/shared/state");
+const { state, loadState, saveState } = require("../src/shared/state");
 const { onChainSwitch } = require("../src/shared/chainSwitch");
 const { NETWORKS } = require("../src/shared/networks");
+const { prices } = require("../src/shared/prices");
+const {
+    goBack,
+    pushCurrentView,
+    setBackRenderer,
+    showView,
+} = require("../src/popup/views/helpers");
+const {
+    makeBackRenderer,
+    resetRenderedViews,
+} = require("../src/popup/viewRouter");
 const txStatus = require("../src/popup/views/txStatus");
 const confirmTx = require("../src/popup/views/confirmTx");
 
 const PRIVATE_KEY = "0x" + "11".repeat(32);
 const HOLDER = new Wallet(PRIVATE_KEY).address;
 const RECIPIENT = "0xC0FfEE0000000000000000000000000000c0fFEe";
+const TOKEN = "0x7070707070707070707070707070707070707070";
 const PASSWORD = "correct horse battery staple";
 
 function el(id) {
@@ -150,7 +197,10 @@ beforeAll(async () => {
 
 beforeEach(() => {
     elements.clear();
+    mockNode.asked = [];
     mockNode.broadcast = [];
+    mockNode.legacyFees = false;
+    global.fetch.mockClear();
     txStatus.showWait.mockClear();
     txStatus.showError.mockClear();
     signTransaction = jest.spyOn(BaseWallet.prototype, "signTransaction");
@@ -160,10 +210,16 @@ afterEach(() => {
     signTransaction.mockRestore();
 });
 
-// Show the confirmation screen for 1 of the native token on `networkId`, as
-// Review on the Send screen does, with its fee estimate settled.
-async function review(networkId) {
+// Show the confirmation screen for 1 of the native token on `networkId`, or
+// for the transfer `changes` makes of it, as Review on the Send screen does,
+// with its fee estimate settled.
+async function review(networkId, changes = {}) {
     await onChainSwitch(networkId);
+    await reviewOnActiveNetwork(changes);
+}
+
+// review() on the network already active, without switching to it again.
+async function reviewOnActiveNetwork(changes = {}) {
     state.wallets = [
         {
             type: "key",
@@ -186,7 +242,90 @@ async function review(networkId) {
         tokenBalance: null,
         tokenDecimals: null,
         max: false,
+        ...changes,
     });
+    await settle();
+}
+
+// The user's own node for a network, set in Settings.
+function ownNode(networkId) {
+    return "https://" + networkId + ".node.example.invalid";
+}
+
+// After review() on `reviewedOn`: the user's own node set for it, the Settings
+// gear, `switchedTo` chosen there, the popup closed and reopened onto
+// Settings, and Back, which draws the confirmation screen again from the
+// transaction it saved. The reopened page holds an ETH price of $2,000 and a
+// USDC price of $1 whichever network is active, so each USD value shows which
+// network it was priced for.
+async function switchReopenAndGoBack(reviewedOn, switchedTo) {
+    state.rpcUrl = ownNode(reviewedOn);
+    pushCurrentView();
+    showView("settings");
+    await onChainSwitch(switchedTo);
+
+    await loadState();
+    elements.clear();
+    resetRenderedViews();
+    setBackRenderer(makeBackRenderer(state, { confirmTx }));
+    confirmTx.init({});
+    prices.ETH = 2000;
+    prices.USDC = 1;
+    mockNode.asked = [];
+    global.fetch.mockClear();
+    goBack();
+    await settle();
+}
+
+// The USD value `text` as the screen appends it for `networkId`: nothing on a
+// testnet, which has no USD values.
+function usdOn(networkId, text) {
+    return NETWORKS[networkId].isTestnet ? "" : " (" + text + ")";
+}
+
+// The screen for the transfer review() shows by default, described on
+// `networkId`: in its native currency, priced by it, linking to its explorer.
+function expectNativeTransferOn(networkId) {
+    const { nativeCurrency: symbol, explorerUrl } = NETWORKS[networkId];
+    expect(el("confirm-type").textContent).toBe(
+        "Native " + symbol + " transfer",
+    );
+    expect(el("confirm-amount").textContent).toBe(
+        "1 " + symbol + usdOn(networkId, "$2,000.00"),
+    );
+    expect(el("confirm-balance").textContent).toBe(
+        "5.0000 " + symbol + usdOn(networkId, "$10,000.00"),
+    );
+    expect(el("confirm-fee-amount").textContent).toBe(
+        "~0.0002 " + symbol + usdOn(networkId, "$0.42"),
+    );
+    expect(el("confirm-fee-reserve").textContent).toBe(
+        "up to 0.0004 " + symbol + " reserved",
+    );
+    expect(el("confirm-gas-error").textContent).toBe(
+        "You do not have enough " +
+            symbol +
+            " to pay the network fee for this transfer. Please add " +
+            symbol +
+            " to this address and try again.",
+    );
+    expect(el("confirm-recipient-warning").textContent).toContain(
+        " holds no " + symbol + ". ",
+    );
+    expect(el("confirm-contract-warning").textContent).toContain(
+        " Sending " + symbol + " or tokens ",
+    );
+    expect(el("confirm-from").innerHTML).toContain(
+        `href="${explorerUrl}/address/${HOLDER}"`,
+    );
+    expect(el("confirm-to").innerHTML).toContain(
+        `href="${explorerUrl}/address/${RECIPIENT}"`,
+    );
+}
+
+// show() estimates the fee and checks the recipient without awaiting either;
+// this lets both finish.
+async function settle() {
     for (let i = 0; i < 10; i++) await new Promise((r) => setTimeout(r, 0));
 }
 
@@ -208,6 +347,24 @@ test("a transfer reviewed on Sepolia and sent goes out on Sepolia", async () =>
     expect(txStatus.showWait).toHaveBeenCalledTimes(1);
 });
 
+// Saving an RPC endpoint in Settings (src/popup/views/settings.js) sets only
+// state.rpcUrl: the endpoint remembered for the active network keeps its old
+// value until the next switch away from it.
+test("a transfer reviewed after the active network's RPC endpoint was changed in Settings asks the new endpoint", async () => {
+    const newNode = "https://new.node.example.invalid";
+    await onChainSwitch("sepolia");
+    state.rpcUrl = newNode;
+    await saveState();
+
+    await reviewOnActiveNetwork();
+
+    expect(mockNode.asked).toEqual([
+        { method: "getFeeData", network: "sepolia", url: newNode },
+        { method: "getCode", network: "sepolia", url: newNode },
+        { method: "getTransactionCount", network: "sepolia", url: newNode },
+    ]);
+});
+
 describe.each([
     ["sepolia", "mainnet", "SepoliaETH"],
     ["mainnet", "sepolia", "ETH"],
@@ -238,6 +395,128 @@ describe.each([
     },
 );
 
+describe.each([
+    ["sepolia", "mainnet"],
+    ["mainnet", "sepolia"],
+])(
+    "a transfer reviewed on %s, with %s chosen in Settings, the popup reopened and Back pressed",
+    (reviewedOn, switchedTo) => {
+        const { nativeCurrency: symbol, explorerUrl } = NETWORKS[reviewedOn];
+
+        test("is described on the network it was reviewed for, and neither signed nor sent", async () => {
+            await review(reviewedOn);
+            await switchReopenAndGoBack(reviewedOn, switchedTo);
+
+            expect(state.currentView).toBe("confirm-tx");
+            expectNativeTransferOn(reviewedOn);
+            expect(mockNode.asked).toEqual([
+                {
+                    method: "getFeeData",
+                    network: reviewedOn,
+                    url: ownNode(reviewedOn),
+                },
+                {
+                    method: "getCode",
+                    network: reviewedOn,
+                    url: ownNode(reviewedOn),
+                },
+                {
+                    method: "getTransactionCount",
+                    network: reviewedOn,
+                    url: ownNode(reviewedOn),
+                },
+            ]);
+            expect(global.fetch.mock.calls.map(([url]) => url)).toEqual([
+                explorerUrl + "/address/" + RECIPIENT,
+            ]);
+            expect(el("btn-confirm-send").disabled).toBe(false);
+
+            await signAndSend();
+
+            expect(signTransaction).not.toHaveBeenCalled();
+            expect(mockNode.broadcast).toEqual([]);
+            expect(txStatus.showWait).not.toHaveBeenCalled();
+            expect(txStatus.showError).not.toHaveBeenCalled();
+            expect(el("confirm-errors").innerHTML).toContain(
+                "The active network changed after this transaction was" +
+                    " reviewed, so it was not sent.",
+            );
+        });
+
+        test("is sent on that network, as described, once it is chosen in Settings again and Back pressed", async () => {
+            await review(reviewedOn);
+            await switchReopenAndGoBack(reviewedOn, switchedTo);
+            // The Settings gear, the reviewed network chosen, and Back, which
+            // only unhides the screen as it was drawn.
+            pushCurrentView();
+            showView("settings");
+            await onChainSwitch(reviewedOn);
+            goBack();
+
+            expect(state.currentView).toBe("confirm-tx");
+            expectNativeTransferOn(reviewedOn);
+
+            await signAndSend();
+
+            const chainId = BigInt(NETWORKS[reviewedOn].chainId);
+            expect(mockNode.broadcast).toHaveLength(1);
+            expect(mockNode.broadcast[0].chainId).toBe(chainId);
+            expect(mockNode.broadcast[0].url).toBe(ownNode(reviewedOn));
+            expect(Transaction.from(mockNode.broadcast[0].signed).chainId).toBe(
+                chainId,
+            );
+            expect(txStatus.showWait).toHaveBeenCalledTimes(1);
+        });
+
+        test("for more than the balance, says so in that network's native currency", async () => {
+            await review(reviewedOn, { amount: "10" });
+            await switchReopenAndGoBack(reviewedOn, switchedTo);
+
+            expect(el("confirm-errors").innerHTML).toContain(
+                "Insufficient balance. You have 5.0000 " +
+                    symbol +
+                    " but are trying to send 10 " +
+                    symbol +
+                    ".",
+            );
+        });
+
+        test("with a fee quoted by a node with no type-2 pricing, shows the fee in that network's native currency and price", async () => {
+            await review(reviewedOn);
+            mockNode.legacyFees = true;
+            await switchReopenAndGoBack(reviewedOn, switchedTo);
+
+            expect(el("confirm-fee-amount").textContent).toBe(
+                "0.0002 " + symbol + usdOn(reviewedOn, "$0.42"),
+            );
+        });
+
+        test("of an ERC-20 token, links the token contract to that network's explorer and prices the token by that network", async () => {
+            await review(reviewedOn, {
+                token: TOKEN,
+                tokenSymbol: "USDC",
+                tokenBalance: "50",
+                tokenDecimals: 6,
+                amount: "10",
+            });
+            await switchReopenAndGoBack(reviewedOn, switchedTo);
+
+            expect(el("confirm-type").textContent).toBe(
+                "ERC-20 token transfer (USDC)",
+            );
+            expect(el("confirm-token-contract").innerHTML).toContain(
+                `href="${explorerUrl}/address/${TOKEN}"`,
+            );
+            expect(el("confirm-amount").textContent).toBe(
+                "10 USDC" + usdOn(reviewedOn, "$10.00"),
+            );
+            expect(el("confirm-balance").textContent).toBe(
+                "50.0000 USDC" + usdOn(reviewedOn, "$50.00"),
+            );
+        });
+    },
+);
+
 // The check in the click handler tells the user; the send itself carries the
 // chain id the screen was drawn for, so a signer on another network's node
 // cannot sign it even if the network changes after that check.

tests/persistedFieldContract.test.js

@@ -453,6 +453,20 @@ const CONTRACT = [
                 views: ["confirm-tx"],
                 restored: false,
             },
+            // A chain id naming no network has no explorer to link to.
+            {
+                value: {
+                    pendingTx: {
+                        token: "ETH",
+                        from: ADDRESS,
+                        to: ADDRESS,
+                        amount: "1",
+                        chainId: "0x5",
+                    },
+                },
+                views: ["confirm-tx"],
+                restored: false,
+            },
             // wait-tx passes on `pendingWait.hash`; restoreWait() has checked
             // the fields below it since it was written, and this is the
             // regression guard.

tests/uniswap.test.js

@@ -1,8 +1,12 @@
 const { AbiCoder, Interface, solidityPacked } = require("ethers");
 const uniswap = require("../src/shared/uniswap");
 
-// A Universal Router on Ethereum Mainnet, chain id 0x1.
+// A Universal Router on Ethereum Mainnet, chain id 0x1: UniversalRouterV2,
+// which reads a command's type with the mask 0x3f.
 const ROUTER_ADDR = "0x66a9893cc07d91d95644aedd05d03f95e1dba8af";
+// Two more there, which read it with 0x1f and 0x7f.
+const ROUTER_V1_ADDR = "0xEf1c6E67703c7BD7107eed8303Fbe6EC2554BF6B";
+const ROUTER_V2_1_2_ADDR = "0x23617e59A5925b2A4Bf75d73ff6711cD0b29De85";
 const USDT_ADDR = "0xdAC17F958D2ee523a2206206994597C13D831ec7";
 const WETH_ADDR = "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2";
 const USDC_ADDR = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48";
@@ -105,6 +109,12 @@ function encodeV4Swap(actions, params) {
     return coder.encode(["bytes", "bytes[]"], [actions, params]);
 }
 
+// Helper: encode an EXECUTE_SUB_PLAN input (command 0x21), which holds the
+// sub-plan's own commands and inputs
+function encodeSubPlan(commands, inputs) {
+    return coder.encode(["bytes", "bytes[]"], [commands, inputs]);
+}
+
 // V4 inner action IDs, as src/shared/uniswap.js names them.
 const V4_SWAP_EXACT_IN = 0x07;
 const V4_SWAP_EXACT_IN_SINGLE_ID = 0x06;
@@ -864,6 +874,177 @@ describe("uniswap decoder", () => {
         );
     });
 
+    // https://git.eeqj.de/sneak/AutistMask/issues/535 — every command's type
+    // was read from its low five bits, as only UniversalRouterV1 reads it, so
+    // the later routers listed 0x21 as a V3 exact-out swap, and
+    // UniversalRouterV2_1_2 listed 0x40 as a V3 exact-in swap.
+    test.each([
+        {
+            router: "UniversalRouterV1",
+            address: ROUTER_V1_ADDR,
+            command: "0x21",
+            steps: "V3 Swap (Exact Out)",
+        },
+        {
+            router: "UniversalRouterV2",
+            address: ROUTER_ADDR,
+            command: "0x21",
+            steps: "Execute Sub-Plan (its steps are not shown)",
+        },
+        {
+            router: "UniversalRouterV2_1_2",
+            address: ROUTER_V2_1_2_ADDR,
+            command: "0x21",
+            steps: "Execute Sub-Plan (its steps are not shown)",
+        },
+        {
+            router: "UniversalRouterV1",
+            address: ROUTER_V1_ADDR,
+            command: "0x40",
+            steps: "V3 Swap (Exact In)",
+        },
+        {
+            router: "UniversalRouterV2",
+            address: ROUTER_ADDR,
+            command: "0x40",
+            steps: "V3 Swap (Exact In)",
+        },
+        {
+            router: "UniversalRouterV2_1_2",
+            address: ROUTER_V2_1_2_ADDR,
+            command: "0x40",
+            steps: "Command 0x40",
+        },
+    ])(
+        "command $command sent to $router is listed as $steps",
+        ({ address, command, steps }) => {
+            const data = buildExecute(command, ["0x"], 9999999999n);
+            const result = uniswap.decode(data, address, "0x1");
+            expect(detail(result, "Steps").value).toBe(steps);
+        },
+    );
+
+    // A sub-plan holding a V3 swap of USDT for WETH, which the decoder does
+    // not read. With the allow-revert flag (0x80) the command byte is 0xa1.
+    test.each([
+        { flag: "without", command: 0x21 },
+        { flag: "with", command: 0xa1 },
+    ])(
+        "an EXECUTE_SUB_PLAN step $flag the allow-revert flag says its steps are not shown",
+        ({ command }) => {
+            const subPlan = encodeSubPlan("0x00", [
+                encodeV3SwapExactIn(USER_ADDR, 2000000n, ONE_WETH, [
+                    USDT_ADDR,
+                    WETH_ADDR,
+                ]),
+            ]);
+            const data = buildExecute(
+                solidityPacked(["uint8"], [command]),
+                [subPlan],
+                9999999999n,
+            );
+            const result = uniswap.decode(data, ROUTER_ADDR, "0x1");
+            expect(result.name).toBe("Uniswap Swap");
+            expect(detail(result, "Steps").value).toBe(
+                "Execute Sub-Plan (its steps are not shown)",
+            );
+            // The sub-plan names both currencies, so the lines must not say
+            // the calldata did not.
+            expect(detail(result, "Token In").value).toBe(
+                "Unknown (could not be decoded)",
+            );
+            expect(detail(result, "Token Out").value).toBe(
+                "Unknown (could not be decoded)",
+            );
+            expect(detail(result, "Amount")).toBeUndefined();
+            expect(detail(result, "Min. received")).toBeUndefined();
+        },
+    );
+
+    // The steps inside a sub-plan may spend the user's tokens or pay the user,
+    // so the steps read beside it are not the whole swap, whether they come
+    // before it or after it. No side is named and no figure is given.
+    test.each([
+        {
+            // 2,000 USDT for at least 1 WETH, paid to the router; the sub-plan
+            // swaps that WETH for USDC.
+            beside: "a swap before",
+            commands: "0x0021",
+            inputs: [
+                encodeV3SwapExactIn(ROUTER_ADDR, 2000000000n, ONE_WETH, [
+                    USDT_ADDR,
+                    WETH_ADDR,
+                ]),
+                encodeSubPlan("0x00", [
+                    encodeV3SwapExactIn(USER_ADDR, ONE_WETH, 2000000000n, [
+                        WETH_ADDR,
+                        USDC_ADDR,
+                    ]),
+                ]),
+            ],
+            steps: "V3 Swap (Exact In) \u2192 Execute Sub-Plan (its steps are not shown)",
+        },
+        {
+            // The sub-plan buys WETH with the user's USDC; 1 WETH is then
+            // swapped for at least 2,000 DAI.
+            beside: "a swap after",
+            commands: "0x2100",
+            inputs: [
+                encodeSubPlan("0x00", [
+                    encodeV3SwapExactIn(ROUTER_ADDR, 2000000000n, ONE_WETH, [
+                        USDC_ADDR,
+                        WETH_ADDR,
+                    ]),
+                ]),
+                encodeV3SwapExactIn(USER_ADDR, ONE_WETH, 2000n * ONE_WETH, [
+                    WETH_ADDR,
+                    DAI_ADDR,
+                ]),
+            ],
+            steps: "Execute Sub-Plan (its steps are not shown) \u2192 V3 Swap (Exact In)",
+        },
+        {
+            // A permit among the sub-plan's steps would replace this one.
+            beside: "a permit before",
+            commands: "0x0a21",
+            inputs: [encodePermit2(USDT_ADDR, 1000000n, ROUTER_ADDR), "0x"],
+            steps: "Permit2 Permit \u2192 Execute Sub-Plan (its steps are not shown)",
+        },
+        {
+            // The sub-plan buys USDC for the user; an UNWRAP_WETH of 0
+            // follows. No step outside the sub-plan sets the output side, and
+            // UNWRAP_WETH would then make Token Out ETH.
+            beside: "an UNWRAP_WETH after",
+            commands: "0x210c",
+            inputs: [
+                encodeSubPlan("0x00", [
+                    encodeV3SwapExactIn(USER_ADDR, 2000000000n, 1900000000n, [
+                        USDT_ADDR,
+                        USDC_ADDR,
+                    ]),
+                ]),
+                encodeWrapEth(USER_ADDR, 0n), // UNWRAP_WETH, same encoding
+            ],
+            steps: "Execute Sub-Plan (its steps are not shown) \u2192 Unwrap WETH",
+        },
+    ])(
+        "$beside an EXECUTE_SUB_PLAN step does not name either side",
+        ({ commands, inputs, steps }) => {
+            const data = buildExecute(commands, inputs, 9999999999n);
+            const result = uniswap.decode(data, ROUTER_ADDR, "0x1");
+            expect(detail(result, "Steps").value).toBe(steps);
+            expect(result.name).toBe("Uniswap Swap");
+            expect(detail(result, "Token In").value).toBe(
+                "Unknown (could not be decoded)",
+            );
+            expect(detail(result, "Amount")).toBeUndefined();
+            expect(detail(result, "Token Out").value).toBe(
+                "Unknown (could not be decoded)",
+            );
+            expect(detail(result, "Min. received")).toBeUndefined();
+        },
+    );
+
     test("shows the deadline as a UTC date and time", () => {
         const result = uniswap.decode(FIRST_SWAP_CALLDATA, ROUTER_ADDR, "0x1");
         expect(detail(result, "Deadline").value).toBe("2026-02-27 08:25:51");