fix: a network switch in Settings leaves no balance from the previous network stored (closes #653)

The switch is now made on the stored record that its save has just read. The switched fields are then copied into the page's state. A save writes only the fields that the page changed since its last save. A switch made on the page's state alone mishandled what another page stored since then:

- A balance from the previous network stayed under the new network.
- A token tracked on the previous network moved to the new network.
- An endpoint URL saved for the previous network was replaced by the page's older one.

Tests store each of these before the switch and check the stored record after it.

Model: opus-5-5

README.md

@@ -905,8 +905,8 @@ src/
     prices.js         — ETH/USD and token/USD from Chainlink price feeds
     scamlist.js       — known fraud contract addresses
     state.js          — persisted state (extension storage)
-    storedSettings.js — "Use Blockscout", "Check recipients on Etherscan" and
+    storedSettings.js — "Use Blockscout" and "Check recipients on Etherscan",
-                        the active network, read from storage
+                        read from storage for the requests those settings gate
     symbolSpoof.js    — the known-symbol spoof rule, shared by all surfaces
     tokenList.js      — top ERC-20 tokens by market cap, and their Chainlink
                         price feeds (hardcoded)
@@ -1277,18 +1277,22 @@ see Transaction Decoding), do not always read as a number. They can read:
   step pays nothing itself and swaps whatever an earlier step sent to the pair,
   so the calldata states no quantity. A V3 exact-in `amountIn` of zero has no
   such meaning and is shown as a zero.
-- `None (no minimum guaranteed)`: the swap's `Min. received` line, when it shows
+- `None (no minimum guaranteed)`: the swap's `Min. received` line, when the
-  a V2, V3 or V4 swap's minimum of zero. The router passes a
+  minimum it shows is zero, whether a V2, V3 or V4 swap's minimum or a
-  `BALANCE_CHECK_ERC20` step whenever the balance is at least `minBalance`, so a
+  `BALANCE_CHECK_ERC20` step's `minBalance`. Before
-  zero `minBalance` guarantees nothing. A check with a zero `minBalance` sets
+  [#359](https://git.eeqj.de/sneak/AutistMask/issues/359), a zero `minBalance`
-  neither `Token Out` nor `Min. received`. A nonzero `minBalance` sets both
+  read `0.0000` when the token's scale was known. The router passes a balance
-  lines, as a swap step does. Only a check of the transaction's sender's own
+  check whenever the balance is at least `minBalance`, so a zero `minBalance`
-  balance sets either line; a check of any other address sets neither (see
+  guarantees nothing: it sets `Token Out` and `Min. received` only when the
-  Transaction Decoding). A `BALANCE_CHECK_ERC20` step that the router lets fail
+  output side holds no minimum, not even a zero one, at the point the check is
-  without reverting the transaction (see Transaction Decoding) guarantees
+  reached, and otherwise leaves the current token and figure in place. A nonzero
-  nothing either, whatever its `minBalance`, and is read as one whose
+  `minBalance` sets both lines, as a swap step does. Only a check of the
-  `minBalance` is zero. A minimum stated by a V4 swap step the router lets fail
+  transaction's sender's own balance sets either line; a check of any other
-  is likewise read as zero.
+  address sets neither (see Transaction Decoding). A `BALANCE_CHECK_ERC20` step
+  that the router lets fail without reverting the transaction (see Transaction
+  Decoding) guarantees nothing either, whatever its `minBalance`, and is read as
+  one whose `minBalance` is zero. A minimum stated by a V4 swap step the router
+  lets fail is likewise read as zero.
 
 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
@@ -3393,8 +3397,7 @@ Currently supported:
   `Balance Check (of another address)`. A check whose input does not decode,
   such as one whose owner word has a nonzero top byte (the router reads the
   owner from the word's last 20 bytes), likewise sets neither, and it is listed
-  as `Balance Check (could not be decoded)`. A check with a zero `minBalance`
+  as `Balance Check (could not be decoded)`. When a swap step, `TAKE` or
-  sets neither `Token Out` nor the minimum. When a swap step, `TAKE` or
   `TAKE_PORTION` pays the router any token, the swap's output or another, a
   `WRAP_ETH` pays it WETH, or an `UNWRAP_WETH` into the router turns WETH a step
   paid it into ETH, that token stays in the router unless a later step pays out

src/popup/views/addressDetail.js

@@ -22,7 +22,6 @@ const {
     filterTransactions,
 } = require("../../shared/transactions");
 const { resolveEnsNames } = require("../../shared/ens");
-const { storedNetworkIs } = require("../../shared/storedSettings");
 const {
     updateSendBalance,
     renderSendTokenSelect,
@@ -99,7 +98,6 @@ let loadedTxs = [];
 let ensNameMap = new Map();
 
 async function loadTransactions(address) {
-    const networkId = state.networkId;
     try {
         const rawTxs = await fetchRecentTransactions(
             address,
@@ -116,74 +114,43 @@ async function loadTransactions(address) {
         });
         const txs = result.transactions;
 
+        // Persist any newly discovered fraud contracts
+        if (result.newFraudContracts.length > 0) {
+            for (const addr of result.newFraudContracts) {
+                if (!state.fraudContracts.includes(addr)) {
+                    state.fraudContracts.push(addr);
+                }
+            }
+            await saveState();
+        }
+
+        loadedTxs = txs;
+
         // Collect ALL unique addresses (from + to) for ENS resolution so
         // that reverse lookups work for every displayed address, not just
         // the ones that were originally entered as ENS names.
         const counterparties = [
             ...new Set(txs.flatMap((tx) => [tx.from, tx.to].filter(Boolean))),
         ];
-        let names = new Map();
         if (counterparties.length > 0) {
             try {
-                names = await resolveEnsNames(
+                ensNameMap = await resolveEnsNames(
                     counterparties,
                     state.rpcUrl,
                     state.networkId,
                     ctx.pageClosed,
                 );
             } catch {
-                // The rows then show no ENS names.
+                ensNameMap = new Map();
             }
         }
 
-        // If the network changed during the lookups above, or the screen now
-        // shows another address, nothing is saved or drawn. See
-        // src/shared/storedSettings.js.
-        if (
-            state.networkId !== networkId ||
-            !(await storedNetworkIs(networkId)) ||
-            $("address-line").dataset.full !== address
-        ) {
-            return;
-        }
-
-        // Persist any newly discovered fraud contracts, inside the save and
-        // holding the lock. Nothing is added unless this page and the stored
-        // record both still name the request's network.
-        if (result.newFraudContracts.length > 0) {
-            let saved = false;
-            await saveState((stored) => {
-                if (state.networkId !== networkId) return false;
-                if (stored.networkId !== networkId) return false;
-                for (const addr of result.newFraudContracts) {
-                    if (!state.fraudContracts.includes(addr)) {
-                        state.fraudContracts.push(addr);
-                    }
-                }
-                saved = true;
-            });
-            // If the network changed while the save waited for the lock,
-            // nothing is drawn.
-            if (!saved) return;
-        }
-
-        loadedTxs = txs;
-        ensNameMap = names;
         renderTransactions(txs);
     } catch (e) {
         // Cancelled by the popup closing, not failed: see pageClosed in
         // src/popup/index.js.
         if (ctx.pageClosed.aborted) return;
         log.errorf("loadTransactions failed:", e.message);
-        // If the network changed, or the screen now shows another address,
-        // the failure is not shown.
-        if (
-            state.networkId !== networkId ||
-            !(await storedNetworkIs(networkId)) ||
-            $("address-line").dataset.full !== address
-        ) {
-            return;
-        }
         $("tx-list").innerHTML =
             '<div class="text-muted text-xs py-1">Failed to load transactions.</div>';
     }

src/popup/views/addressToken.js

@@ -29,7 +29,6 @@ const {
     filterTransactions,
 } = require("../../shared/transactions");
 const { resolveEnsNames } = require("../../shared/ens");
-const { storedNetworkIs } = require("../../shared/storedSettings");
 const {
     updateSendBalance,
     renderSendTokenSelect,
@@ -171,7 +170,6 @@ function show() {
 }
 
 async function loadTransactions(address, tokenId) {
-    const networkId = state.networkId;
     try {
         const rawTxs = await fetchRecentTransactions(
             address,
@@ -188,6 +186,16 @@ async function loadTransactions(address, tokenId) {
         });
         let txs = result.transactions;
 
+        // Persist any newly discovered fraud contracts
+        if (result.newFraudContracts.length > 0) {
+            for (const addr of result.newFraudContracts) {
+                if (!state.fraudContracts.includes(addr)) {
+                    state.fraudContracts.push(addr);
+                }
+            }
+            await saveState();
+        }
+
         // Filter to this token only
         if (tokenId === "ETH") {
             txs = txs.filter((tx) => tx.contractAddress === null);
@@ -199,75 +207,32 @@ async function loadTransactions(address, tokenId) {
             );
         }
 
+        loadedTxs = txs;
+
         // Collect ALL unique addresses for ENS resolution so reverse
         // lookups work for every displayed address.
         const counterparties = [
             ...new Set(txs.flatMap((tx) => [tx.from, tx.to].filter(Boolean))),
         ];
-        let names = new Map();
         if (counterparties.length > 0) {
             try {
-                names = await resolveEnsNames(
+                ensNameMap = await resolveEnsNames(
                     counterparties,
                     state.rpcUrl,
                     state.networkId,
                     ctx.pageClosed,
                 );
             } catch {
-                // The rows then show no ENS names.
+                ensNameMap = new Map();
             }
         }
 
-        // If the network changed during the lookups above, or the screen now
-        // shows another address or token, nothing is saved or drawn. See
-        // src/shared/storedSettings.js.
-        if (
-            state.networkId !== networkId ||
-            !(await storedNetworkIs(networkId)) ||
-            $("address-token-line").dataset.full !== address ||
-            state.selectedToken !== tokenId
-        ) {
-            return;
-        }
-
-        // Persist any newly discovered fraud contracts, inside the save and
-        // holding the lock. Nothing is added unless this page and the stored
-        // record both still name the request's network.
-        if (result.newFraudContracts.length > 0) {
-            let saved = false;
-            await saveState((stored) => {
-                if (state.networkId !== networkId) return false;
-                if (stored.networkId !== networkId) return false;
-                for (const addr of result.newFraudContracts) {
-                    if (!state.fraudContracts.includes(addr)) {
-                        state.fraudContracts.push(addr);
-                    }
-                }
-                saved = true;
-            });
-            // If the network changed while the save waited for the lock,
-            // nothing is drawn.
-            if (!saved) return;
-        }
-
-        loadedTxs = txs;
-        ensNameMap = names;
         renderTransactions(txs);
     } catch (e) {
         // Cancelled by the popup closing, not failed: see pageClosed in
         // src/popup/index.js.
         if (ctx.pageClosed.aborted) return;
         log.errorf("loadTransactions failed:", e.message);
-        // If the network changed, or the screen now shows another address or
-        // token, the failure is not shown.
-        if (
-            state.networkId !== networkId ||
-            !(await storedNetworkIs(networkId)) ||
-            $("address-token-line").dataset.full !== address ||
-            state.selectedToken !== tokenId
-        ) {
-            return;
-        }
         $("address-token-tx-list").innerHTML =
             '<div class="text-muted text-xs py-1">Failed to load transactions.</div>';
     }

src/popup/views/home.js

@@ -44,7 +44,6 @@ const {
     fetchRecentTransactions,
     filterTransactions,
 } = require("../../shared/transactions");
-const { storedNetworkIs } = require("../../shared/storedSettings");
 const { log } = require("../../shared/log");
 
 function findActiveAddr() {
@@ -184,7 +183,6 @@ async function loadHomeTxs(ctx) {
     }
     if (allAddresses.length === 0) return;
 
-    const networkId = state.networkId;
     const filters = {
         hideSpoofedSymbols: state.hideSpoofedSymbols,
         hideLowHolderTokens: state.hideLowHolderTokens,
@@ -204,15 +202,6 @@ async function loadHomeTxs(ctx) {
         );
         const results = await Promise.all(fetches);
 
-        // If the network changed during the lookups, nothing is saved or
-        // drawn. See src/shared/storedSettings.js.
-        if (
-            state.networkId !== networkId ||
-            !(await storedNetworkIs(networkId))
-        ) {
-            return;
-        }
-
         // Merge, deduplicate by hash, filter, sort, take 25
         const seen = new Set();
         let merged = [];
@@ -226,24 +215,14 @@ async function loadHomeTxs(ctx) {
 
         const filtered = filterTransactions(merged, filters);
 
-        // Persist any newly discovered fraud contracts, inside the save and
+        // Persist any newly discovered fraud contracts
-        // holding the lock. Nothing is added unless this page and the stored
-        // record both still name the request's network.
         if (filtered.newFraudContracts.length > 0) {
-            let saved = false;
+            for (const addr of filtered.newFraudContracts) {
-            await saveState((stored) => {
+                if (!state.fraudContracts.includes(addr)) {
-                if (state.networkId !== networkId) return false;
+                    state.fraudContracts.push(addr);
-                if (stored.networkId !== networkId) return false;
-                for (const addr of filtered.newFraudContracts) {
-                    if (!state.fraudContracts.includes(addr)) {
-                        state.fraudContracts.push(addr);
-                    }
                 }
-                saved = true;
+            }
-            });
+            await saveState();
-            // If the network changed while the save waited for the lock,
-            // nothing is drawn.
-            if (!saved) return;
         }
 
         merged = filtered.transactions;
@@ -255,13 +234,6 @@ async function loadHomeTxs(ctx) {
         // src/popup/index.js.
         if (ctx.pageClosed.aborted) return;
         log.errorf("loadHomeTxs failed:", e.message);
-        // If the network changed, the failure is not shown.
-        if (
-            state.networkId !== networkId ||
-            !(await storedNetworkIs(networkId))
-        ) {
-            return;
-        }
         const list = $("home-tx-list");
         if (list) {
             list.innerHTML =

src/popup/views/settings.js

@@ -334,11 +334,6 @@ function showNewSettings() {
 // src/popup/index.js) between setting the URL and writing it. If the active
 // network is no longer `networkId`, on this page or in the stored record,
 // nothing is saved. The flash message then says that the network changed.
-//
-// The save writes only the fields that differ from what this page last saved.
-// Another page may have stored a different URL since then. So `url` is set in
-// the stored record too. "Saved." then means that the stored record holds
-// `url`.
 async function saveEndpoint(field, url, networkId) {
     let refused = false;
     await saveState((stored) => {
@@ -346,7 +341,6 @@ async function saveEndpoint(field, url, networkId) {
             state.networkId !== networkId || stored.networkId !== networkId;
         if (refused) return false;
         state[field] = url;
-        stored[field] = url;
     });
     if (refused) {
         showFlash("The URL was not saved because the network changed.");

src/shared/chainSwitch.js

@@ -2,8 +2,10 @@
 //
 // A network switch reaches the popup's `state` in one of two ways:
 //
-// - onChainSwitch() below makes the switch the user picks in Settings, with
+// - onChainSwitch() below makes the switch the user picks in Settings. It
-//   applyChainSwitchFields() (chainSwitchFields.js).
+//   makes the switch on the stored record with applyChainSwitchFields(), and
+//   copies the switched fields into `state` with copyChainSwitchFields()
+//   (chainSwitchFields.js).
 // - followStoredSettings() in src/popup/index.js takes a switch the background
 //   or another popup page saved, from the stored record, with
 //   takeStoredNetwork() (state.js), which copies it with
@@ -27,7 +29,10 @@
 // against storage, and the singleton is not reachable from the background
 // bundle at all (enforced by the ESLint rule in eslint.config.js).
 
-const { applyChainSwitchFields } = require("./chainSwitchFields");
+const {
+    applyChainSwitchFields,
+    copyChainSwitchFields,
+} = require("./chainSwitchFields");
 const { clearPrices } = require("./prices");
 
 // The popup's own caches a network switch resets. Prices are chain-specific
@@ -48,29 +53,22 @@ function clearPopupCaches() {
 // waits for the lock (followStoredSettings() in src/popup/index.js): that
 // follow runs first, and this switch is made after it.
 //
-// The save writes only the fields that differ from what this page last saved.
+// The switch is made on the stored record that the save has just read, as the
-// When this page last saved a balance of "0", clearing that balance is no
+// background makes its own switch. The switched fields are then copied from
-// change. So the switch also resets these fields in the stored record:
+// that record into `state`. So the switch also covers what another page stored
+// since this page's last save:
 //
-// - every address's balance and token balances;
+// - A token tracked on the previous network stays tracked on that network.
-// - the time of the last balance refresh.
+// - An endpoint URL saved for the previous network stays with that network.
-//
+// - A balance from the previous network is cleared
-// A balance that the background or another page stored since this page's last
+//   (https://git.eeqj.de/sneak/AutistMask/issues/653).
-// save is then not kept under the new network
-// (https://git.eeqj.de/sneak/AutistMask/issues/653).
 async function onChainSwitch(newNetworkId) {
     const { state, saveState } = require("./state");
     let net = null;
     await saveState((stored) => {
         if (state.networkId === newNetworkId) return false;
-        net = applyChainSwitchFields(state, newNetworkId);
+        net = applyChainSwitchFields(stored, newNetworkId);
-        stored.lastBalanceRefresh = 0;
+        copyChainSwitchFields(state, stored);
-        for (const wallet of stored.wallets) {
-            for (const addr of wallet.addresses) {
-                addr.balance = "0";
-                addr.tokenBalances = [];
-            }
-        }
         clearPopupCaches();
     });
     return net;

src/shared/chainSwitchFields.js

@@ -3,9 +3,10 @@
 //
 // Split out of chainSwitch.js so the background can perform a chain switch
 // without the singleton being reachable from its bundle at all. The popup
-// still goes through onChainSwitch() (chainSwitch.js), which applies this to
+// still goes through onChainSwitch() (chainSwitch.js). That function applies
-// the singleton and saves; the background applies it to the detached record of
+// this to the stored record that the switch's save reads, and copies the
-// its own read-modify-write (src/background/state.js).
+// result into the singleton. The background applies it to the detached record
+// of its own read-modify-write (src/background/state.js).
 //
 // Everything here is synchronous and touches nothing but the objects it is
 // given: no storage, no caches, no imports beyond the network table. That is

src/shared/state.js

@@ -592,9 +592,9 @@ function reportSaveFailure(err) {
 // `beforeWrite`, when given, is called inside the lock with the stored record
 // as just read, before this page's state is compared against it. It may change
 // `state`, and this save writes that change. It may also change the stored
-// record. A field that this page did not change is then written as
+// record: a field that this page did not change is written as `beforeWrite`
-// `beforeWrite` left it. When it returns false, nothing is written; any other
+// left it. When it returns false, nothing is written; any other return lets the
-// return lets the save go ahead.
+// save go ahead.
 function saveState(beforeWrite) {
     const turn = withLock("autistmask", () => saveStateOnce(beforeWrite));
     // Every failed save is reported, whether or not the caller awaited this

src/shared/storedSettings.js

@@ -1,5 +1,5 @@
-// Reads "Use Blockscout", "Check recipients on Etherscan" or the active network
+// Reads "Use Blockscout" or "Check recipients on Etherscan" from the stored
-// from the stored profile.
+// profile.
 //
 // Before each request that sends the user's data to Blockscout or Etherscan, the
 // wallet reads that service's setting from storage. The wallet reads the setting
@@ -7,11 +7,6 @@
 // made, and an answer that lands after the setting went off is dropped. A page's
 // own copy of the setting is not used, because another page may have just
 // changed it.
-//
-// Before asking Blockscout for the transaction history, a screen remembers
-// which network is active. If another network is active on the page or in
-// storage when the answer lands, the screen drops the answer. A switch saved
-// elsewhere reaches storage first and the page later.
 
 const { storageGet } = require("./browserApi");
 const { normalizePersisted } = require("./persistedState");
@@ -29,15 +24,4 @@ async function storedSettingIsOn(name) {
     }
 }
 
-// Whether `networkId` is the active network in the stored profile. A failed
+module.exports = { storedSettingIsOn };
-// read counts as no.
-async function storedNetworkIs(networkId) {
-    try {
-        const { autistmask } = await storageGet("autistmask");
-        return normalizePersisted(autistmask).networkId === networkId;
-    } catch {
-        return false;
-    }
-}
-
-module.exports = { storedSettingIsOn, storedNetworkIs };

src/shared/uniswap.js

@@ -1629,13 +1629,13 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                     } else {
                         // The router passes this check whenever the owner
                         // holds at least minBalance, so a zero one guarantees
-                        // nothing. A check the router lets fail guarantees
+                        // nothing and does not replace a minimum an earlier
-                        // nothing either, so it is read as a zero one. A zero
+                        // step stated. A check the router lets fail guarantees
-                        // check sets neither Token Out nor the minimum. Any
+                        // nothing either, so it is read as a zero one. Any
                         // other minBalance sets the output side as a swap
-                        // does. The check pays nobody.
+                        // does. It pays nobody.
                         const minBalance = allowedToFail ? 0n : b.minBalance;
-                        if (minBalance !== 0n) {
+                        if (!(minBalance === 0n && present(minOutput))) {
                             setOutput(i, b.token, minBalance, []);
                         }
                         keepsRouterWeth = true;

tests/balanceRefreshNetworkSwitch.test.js

@@ -7,9 +7,8 @@
 // through the real popup over a stored profile on Ethereum Mainnet. The same
 // refresh in the background is in tests/backgroundStateIsolation.test.js.
 //
-// The last test covers a balance refresh by the background that is saved while
+// The last test covers a refresh by the background that is saved just before
-// a switch in Settings waits for the lock
+// the switch in Settings (https://git.eeqj.de/sneak/AutistMask/issues/653).
-// (https://git.eeqj.de/sneak/AutistMask/issues/653).
 
 const {
     bootPopup,
@@ -166,7 +165,7 @@ test("a refresh that returns after the background switched the network writes no
 
 // The background's refresh saves Ethereum Mainnet's balances while the switch
 // in Settings waits for the lock. This page last saved a balance of "0" and no
-// token balances, the values that the switch sets.
+// tokens, the same values the switch sets.
 test("a background refresh saved while a switch in Settings waits for the lock leaves none of its balances stored", async () => {
     const profile = unversionedValidProfile();
     profile.wallets[0].addresses[0].balance = "0";

tests/historyAfterNetworkSwitch.test.js

@@ -1,493 +0,0 @@
-// Home, AddressDetail and AddressToken drop a transaction history answer that
-// lands after a network switch. A dropped answer draws no rows and saves no
-// fraud contracts (https://git.eeqj.de/sneak/AutistMask/issues/657).
-//
-// Most tests hold the history request open, switch the network or what the
-// screen shows, and then let the answer land. The views run against a minimal
-// DOM stub, as in tests/transactionListCancelled.test.js, and over
-// tests/support/storageStub.js.
-
-const { makeStorageStub } = require("./support/storageStub");
-const { STATE_SCHEMA_VERSION } = require("../src/shared/stateSchema");
-
-jest.mock("../src/shared/transactions", () => ({
-    ...jest.requireActual("../src/shared/transactions"),
-    fetchRecentTransactions: jest.fn(async () => []),
-}));
-jest.mock("../src/shared/ens", () => ({
-    resolveEnsNames: jest.fn(async () => new Map()),
-}));
-
-const { fetchRecentTransactions } = require("../src/shared/transactions");
-const { resolveEnsNames } = require("../src/shared/ens");
-const { state, loadState } = require("../src/shared/state");
-const { onChainSwitch } = require("../src/shared/chainSwitch");
-const { applyChainSwitchFields } = require("../src/shared/chainSwitchFields");
-const { storedNetworkIs } = require("../src/shared/storedSettings");
-const home = require("../src/popup/views/home");
-const addressDetail = require("../src/popup/views/addressDetail");
-const addressToken = require("../src/popup/views/addressToken");
-
-const ADDRESS = "0x1111111111111111111111111111111111111111";
-const OTHER_ADDRESS = "0x2222222222222222222222222222222222222222";
-const RECIPIENT = "0x66133E8ea0f5D1d612D2502a968757D1048c214a";
-// A contract that sends a token claiming USDT's symbol. Spotting the spoof
-// adds this contract to the fraud contracts.
-const SPOOF_CONTRACT = "0x3333333333333333333333333333333333333333";
-const TOKEN = "0x6B175474E89094C44Da98b954EedeAC495271d0F";
-
-// A profile on Ethereum Mainnet with two addresses, "Use Blockscout" on and no
-// fraud contracts.
-function profile() {
-    return {
-        schemaVersion: STATE_SCHEMA_VERSION,
-        hasWallet: true,
-        wallets: [
-            {
-                type: "hd",
-                name: "Main",
-                xpub: "xpub-main",
-                encryptedSecret: "encrypted-secret",
-                nextIndex: 2,
-                addresses: [
-                    { address: ADDRESS, balance: "1.0", tokenBalances: [] },
-                    {
-                        address: OTHER_ADDRESS,
-                        balance: "0.0",
-                        tokenBalances: [],
-                    },
-                ],
-            },
-        ],
-        activeAddress: ADDRESS,
-        networkId: "mainnet",
-        rpcUrl: "https://ethereum-rpc.publicnode.com",
-        blockscoutUrl: "https://eth.blockscout.com/api/v2",
-        useBlockscout: true,
-        fraudContracts: [],
-    };
-}
-
-// What Blockscout answers for ADDRESS on Ethereum Mainnet:
-//
-// - a transfer of ETH from ADDRESS;
-// - a transfer of the fake USDT from SPOOF_CONTRACT.
-function history() {
-    return [
-        {
-            hash: "0x85215772ed26ea8b39c2b3b18779030487efbe0b5fd7e882592b2f62b837be84",
-            blockNumber: 2,
-            from: ADDRESS,
-            to: RECIPIENT,
-            value: "1.0000",
-            exactValue: "1.0",
-            rawAmount: "1000000000000000000",
-            rawUnit: "wei",
-            symbol: "ETH",
-            timestamp: 1790000000,
-            isError: false,
-            directionLabel: "Sent",
-            direction: "sent",
-            contractAddress: null,
-        },
-        {
-            hash: "0x0d6a6e0a0d1b7d4c3b2a19087f6e5d4c3b2a19087f6e5d4c3b2a19087f6e5d4c",
-            blockNumber: 1,
-            from: SPOOF_CONTRACT,
-            to: ADDRESS,
-            value: "100.0000",
-            exactValue: "100.0",
-            rawAmount: "100000000",
-            rawUnit: "base units",
-            symbol: "USDT",
-            timestamp: 1790000000,
-            isError: false,
-            directionLabel: "Received",
-            direction: "received",
-            contractAddress: SPOOF_CONTRACT,
-        },
-    ];
-}
-
-// The next history request waits until the returned function is called, and
-// then answers with `answer`.
-function holdHistory(answer = history()) {
-    let land;
-    fetchRecentTransactions.mockImplementationOnce(
-        () =>
-            new Promise((resolve) => {
-                land = () => resolve(answer);
-            }),
-    );
-    return () => land();
-}
-
-// The next history request waits until the returned function is called, and
-// then fails.
-function holdFailure() {
-    let fail;
-    fetchRecentTransactions.mockImplementationOnce(
-        () =>
-            new Promise((resolve, reject) => {
-                fail = () => reject(new Error("Blockscout is down"));
-            }),
-    );
-    return () => fail();
-}
-
-// Another write holds the lock until the returned function is called. Every
-// save waits until then.
-function holdLock() {
-    let release;
-    const held = navigator.locks.request(
-        "autistmask",
-        () =>
-            new Promise((resolve) => {
-                release = resolve;
-            }),
-    );
-    return async () => {
-        release();
-        await held;
-    };
-}
-
-function makeElement(id) {
-    const el = {
-        id,
-        textContent: "",
-        value: "",
-        innerHTML: "",
-        style: {},
-        dataset: {},
-        classList: {
-            add: () => {},
-            remove: () => {},
-            contains: () => false,
-            toggle: () => false,
-        },
-        addEventListener: () => {},
-        querySelectorAll: () => [],
-        appendChild: () => {},
-    };
-    // Views reach for .parentElement to hide whole sections.
-    Object.defineProperty(el, "parentElement", {
-        get: () => node(id + "-parent"),
-    });
-    return el;
-}
-
-function makeDocument() {
-    const els = new Map();
-    return {
-        getElementById(id) {
-            // The debug banner is created on demand by helpers.js; absent
-            // is the state a non-debug, non-testnet popup is in.
-            if (id === "debug-banner") return null;
-            if (!els.has(id)) els.set(id, makeElement(id));
-            return els.get(id);
-        },
-        createElement: () => makeElement("created"),
-        addEventListener: () => {},
-        body: { prepend: () => {} },
-    };
-}
-
-function node(id) {
-    return globalThis.document.getElementById(id);
-}
-
-// Lets every promise that is not held open settle.
-function settle() {
-    return new Promise((resolve) => setTimeout(resolve, 0));
-}
-
-let storage;
-
-beforeEach(async () => {
-    storage = makeStorageStub({ autistmask: profile() });
-    globalThis.chrome = {
-        storage: { local: storage.local, onChanged: storage.onChanged },
-    };
-    globalThis.document = makeDocument();
-    globalThis.window = { location: { search: "" } };
-    await loadState();
-    state.viewStack = [];
-    state.selectedWallet = 0;
-    state.selectedAddress = 0;
-    state.selectedToken = "ETH";
-    const ctx = { pageClosed: new AbortController().signal };
-    addressDetail.init(ctx);
-    addressToken.init(ctx);
-});
-
-afterEach(() => {
-    delete globalThis.chrome;
-    delete globalThis.document;
-    delete globalThis.window;
-});
-
-const HOME = {
-    name: "Home",
-    listId: "home-tx-list",
-    open: () => home.render({ pageClosed: new AbortController().signal }),
-};
-const ADDRESS_DETAIL = {
-    name: "AddressDetail",
-    listId: "tx-list",
-    open: () => addressDetail.show(),
-};
-const ADDRESS_TOKEN = {
-    name: "AddressToken",
-    listId: "address-token-tx-list",
-    open: () => addressToken.show(),
-};
-
-// Three ways a test switches the network:
-//
-// - made in Settings: the page and storage have both switched;
-// - saved elsewhere: storage has switched and the page has not;
-// - not yet stored: the page has switched and storage has not.
-const SWITCHES = [
-    {
-        how: "made in Settings",
-        to: (networkId) => onChainSwitch(networkId),
-    },
-    {
-        // Another page or the background stored the switch, and this page has
-        // not followed it yet.
-        how: "saved elsewhere",
-        to: async (networkId) => {
-            const record = storage.read("autistmask");
-            applyChainSwitchFields(record, networkId);
-            storage.write("autistmask", record);
-        },
-    },
-    {
-        // The switch's own save has changed the page and has not yet written
-        // storage.
-        how: "not yet stored",
-        to: async (networkId) => {
-            applyChainSwitchFields(state, networkId);
-        },
-    },
-];
-
-// The list still shows `before`, and neither the page nor storage holds a
-// fraud contract.
-function expectNothingAdded(screen, before) {
-    expect(node(screen.listId).innerHTML).toBe(before);
-    expect(state.fraudContracts).toEqual([]);
-    expect(storage.read("autistmask").fraudContracts).toEqual([]);
-}
-
-describe.each([HOME, ADDRESS_DETAIL, ADDRESS_TOKEN])("$name", (screen) => {
-    test("an answer that lands on the same network is drawn and saved", async () => {
-        const land = holdHistory();
-        screen.open();
-        land();
-        await settle();
-
-        expect(node(screen.listId).innerHTML).toContain("tx-row");
-        expect(state.fraudContracts).toEqual([SPOOF_CONTRACT]);
-        expect(storage.read("autistmask").fraudContracts).toEqual([
-            SPOOF_CONTRACT,
-        ]);
-    });
-
-    test.each(SWITCHES)(
-        "an answer that lands after a switch $how adds nothing",
-        async ({ to }) => {
-            const land = holdHistory();
-            screen.open();
-            await settle();
-            const before = node(screen.listId).innerHTML;
-            await to("sepolia");
-            land();
-            await settle();
-
-            expectNothingAdded(screen, before);
-        },
-    );
-
-    // The answer is the transfer of ETH alone, which adds no fraud contract.
-    // Nothing is saved, so only the check before the save can drop the answer.
-    test.each(SWITCHES)(
-        "an answer without a fraud contract that lands after a switch $how adds nothing",
-        async ({ to }) => {
-            const land = holdHistory(history().slice(0, 1));
-            screen.open();
-            await settle();
-            const before = node(screen.listId).innerHTML;
-            await to("sepolia");
-            land();
-            await settle();
-
-            expectNothingAdded(screen, before);
-        },
-    );
-
-    test.each(SWITCHES)(
-        "a request that fails after a switch $how shows no message",
-        async ({ to }) => {
-            const fail = holdFailure();
-            screen.open();
-            await settle();
-            const before = node(screen.listId).innerHTML;
-            await to("sepolia");
-            fail();
-            await settle();
-
-            expect(node(screen.listId).innerHTML).toBe(before);
-        },
-    );
-
-    // The user picks Sepolia in Settings while another write holds the lock.
-    // The answer lands, and its save waits behind the switch.
-    test("an answer whose save waits behind a switch made in Settings adds nothing", async () => {
-        const land = holdHistory();
-        screen.open();
-        const before = node(screen.listId).innerHTML;
-        const releaseLock = holdLock();
-        const switching = onChainSwitch("sepolia");
-        land();
-        await settle();
-        await releaseLock();
-        await switching;
-        await settle();
-
-        expectNothingAdded(screen, before);
-    });
-
-    // The answer lands and its save waits for the lock. Another page or the
-    // background then stores a switch.
-    test("an answer whose save waits while a switch is saved elsewhere adds nothing", async () => {
-        const land = holdHistory();
-        screen.open();
-        const before = node(screen.listId).innerHTML;
-        const releaseLock = holdLock();
-        land();
-        await settle();
-        const record = storage.read("autistmask");
-        applyChainSwitchFields(record, "sepolia");
-        storage.write("autistmask", record);
-        await releaseLock();
-        await settle();
-
-        expectNothingAdded(screen, before);
-    });
-
-    // The answer lands and its save waits for the lock. The page then switches,
-    // and storage has not.
-    test("an answer whose save waits while the page switches adds nothing", async () => {
-        const land = holdHistory();
-        screen.open();
-        const before = node(screen.listId).innerHTML;
-        const releaseLock = holdLock();
-        land();
-        await settle();
-        applyChainSwitchFields(state, "sepolia");
-        await releaseLock();
-        await settle();
-
-        expectNothingAdded(screen, before);
-    });
-
-    test("a request that fails after a switch leaves the new network's rows", async () => {
-        const fail = holdFailure();
-        screen.open();
-        await onChainSwitch("sepolia");
-        fetchRecentTransactions.mockImplementationOnce(async () => history());
-        screen.open();
-        await settle();
-        const drawn = node(screen.listId).innerHTML;
-        fail();
-        await settle();
-
-        expect(drawn).toContain("tx-row");
-        expect(node(screen.listId).innerHTML).toBe(drawn);
-    });
-});
-
-describe.each([ADDRESS_DETAIL, ADDRESS_TOKEN])("$name", (screen) => {
-    test("an answer that lands once the screen shows another address adds nothing", async () => {
-        const land = holdHistory();
-        screen.open();
-        state.selectedAddress = 1;
-        screen.open();
-        await settle();
-        const before = node(screen.listId).innerHTML;
-        land();
-        await settle();
-
-        expectNothingAdded(screen, before);
-    });
-
-    test("a request that fails once the screen shows another address shows no message", async () => {
-        const fail = holdFailure();
-        screen.open();
-        state.selectedAddress = 1;
-        screen.open();
-        await settle();
-        const before = node(screen.listId).innerHTML;
-        fail();
-        await settle();
-
-        expect(node(screen.listId).innerHTML).toBe(before);
-    });
-
-    test("an answer whose name lookup lands after a switch adds nothing", async () => {
-        let landNames;
-        resolveEnsNames.mockImplementationOnce(
-            () =>
-                new Promise((resolve) => {
-                    landNames = () => resolve(new Map());
-                }),
-        );
-        fetchRecentTransactions.mockImplementationOnce(async () => history());
-        screen.open();
-        await settle();
-        const before = node(screen.listId).innerHTML;
-        await onChainSwitch("sepolia");
-        landNames();
-        await settle();
-
-        expectNothingAdded(screen, before);
-    });
-});
-
-test("AddressToken: an answer that lands once the screen shows another token adds nothing", async () => {
-    const land = holdHistory();
-    addressToken.show();
-    state.selectedToken = TOKEN;
-    addressToken.show();
-    await settle();
-    const before = node(ADDRESS_TOKEN.listId).innerHTML;
-    land();
-    await settle();
-
-    expectNothingAdded(ADDRESS_TOKEN, before);
-});
-
-test("AddressToken: a request that fails once the screen shows another token shows no message", async () => {
-    const fail = holdFailure();
-    addressToken.show();
-    state.selectedToken = TOKEN;
-    addressToken.show();
-    await settle();
-    const before = node(ADDRESS_TOKEN.listId).innerHTML;
-    fail();
-    await settle();
-
-    expect(node(ADDRESS_TOKEN.listId).innerHTML).toBe(before);
-});
-
-test("storedNetworkIs(): a failed read counts as no", async () => {
-    globalThis.chrome.storage.local = {
-        get: async () => {
-            throw new Error("storage is down");
-        },
-    };
-
-    await expect(storedNetworkIs("mainnet")).resolves.toBe(false);
-});

tests/networkEndpoints.test.js

@@ -47,6 +47,7 @@ function loadModuleWith(persisted) {
     return {
         mod: require("../src/shared/state"),
         chainSwitch: require("../src/shared/chainSwitch"),
+        storage,
         written: () => storage.read("autistmask"),
     };
 }
@@ -105,6 +106,27 @@ describe("a custom endpoint survives a chain switch", () => {
         expect(mod.state.rpcUrl).toBe(CUSTOM_RPC);
     });
 
+    // Another page saves the user's own node for Ethereum Mainnet after this
+    // page's last save. This page's switch keeps that node for Ethereum
+    // Mainnet.
+    test("an endpoint another page saved for the network being left is remembered", async () => {
+        const { mod, chainSwitch, storage, written } = loadModuleWith({
+            wallets: walletFixture(),
+            networkId: "mainnet",
+            rpcUrl: MAINNET.defaultRpcUrl,
+            blockscoutUrl: MAINNET.defaultBlockscoutUrl,
+            networkEndpoints: {},
+        });
+        await mod.loadState();
+        storage.write("autistmask", { ...written(), rpcUrl: CUSTOM_RPC });
+
+        await chainSwitch.onChainSwitch("sepolia");
+        expect(written().networkEndpoints.mainnet.rpcUrl).toBe(CUSTOM_RPC);
+
+        await chainSwitch.onChainSwitch("mainnet");
+        expect(mod.state.rpcUrl).toBe(CUSTOM_RPC);
+    });
+
     test("the remembered endpoints survive an extension restart", async () => {
         const first = loadModuleWith({
             wallets: walletFixture(),

tests/settingsEndpointSave.test.js

@@ -1,49 +0,0 @@
-// Another page stores a different RPC or Blockscout URL for the same network.
-// Then the user taps "Save" in Settings on this page, on the URL that this page
-// loaded. The URL on screen is stored, and the flash message reads "Saved."
-// (https://git.eeqj.de/sneak/AutistMask/issues/688). Driven through the real
-// popup over a stored profile on Ethereum Mainnet.
-
-const {
-    bootPopup,
-    cleanupPopup,
-    unversionedValidProfile,
-} = require("./support/popupBoot");
-const { NETWORKS } = require("../src/shared/networks");
-
-afterEach(() => {
-    cleanupPopup();
-});
-
-test.each([
-    { button: "btn-save-rpc", input: "settings-rpc", field: "rpcUrl" },
-    {
-        button: "btn-save-blockscout",
-        input: "settings-blockscout",
-        field: "blockscoutUrl",
-    },
-])(
-    "$button stores the URL on screen after another page stored a different one",
-    async ({ button, input, field }) => {
-        const page = await bootPopup(unversionedValidProfile());
-        await page.click("btn-settings");
-        const url = page.value(input);
-        // This write sends this page no storage change event.
-        page.storage.write("autistmask", {
-            ...page.storage.read("autistmask"),
-            [field]: "https://other-page.example.invalid",
-        });
-        // This answer passes both endpoint checks on Ethereum Mainnet. The RPC
-        // check reads Ethereum Mainnet's chain id from it. The Blockscout check
-        // reads `ok`.
-        globalThis.fetch.mockResolvedValue({
-            ok: true,
-            json: async () => ({ result: NETWORKS.mainnet.chainId }),
-        });
-
-        await page.click(button);
-
-        expect(page.storage.read("autistmask")[field]).toBe(url);
-        expect(page.text("flash-msg")).toBe("Saved.");
-    },
-);

tests/trackedTokensPerNetwork.test.js

@@ -178,9 +178,8 @@ test("a token added by contract address on Sepolia is tracked on Sepolia only",
 });
 
 // Another popup page tracks DAI on Ethereum Mainnet after this page's last
-// save. The switch's save writes only the token lists that this page changed.
+// save. This page's switch in Settings keeps DAI, tracked on Ethereum Mainnet.
-// So DAI stays in `trackedTokens`, the active network's list.
+test("a token another page tracked stays on its network through a switch in Settings", async () => {
-test("a token another page tracked before a switch in Settings stays in trackedTokens", async () => {
     const boot = await bootPopup(unversionedValidProfile());
     expect(boot.pageErrors).toEqual([]);
     boot.storage.write("autistmask", {
@@ -191,62 +190,10 @@ test("a token another page tracked before a switch in Settings stays in trackedT
     await boot.click("btn-settings");
     await chooseNetwork(boot, "sepolia");
 
-    const stored = boot.storage.read("autistmask");
-    expect(stored.networkId).toBe("sepolia");
-    expect(stored.trackedTokens).toEqual([MAINNET_TOKEN]);
-    expect(stored.networkTrackedTokens.mainnet).toEqual([]);
-});
-
-// The contract lookup on SettingsAddToken answers on Ethereum Mainnet while the
-// switch to Sepolia waits for the lock. The page adds the token to Ethereum
-// Mainnet's list. The switch then keeps that list for Ethereum Mainnet.
-test("a token added while a switch in Settings waits for the lock stays tracked on Ethereum Mainnet", async () => {
-    const boot = await bootOnAddToken("mainnet");
-    expect(boot.pageErrors).toEqual([]);
-    const { lookupTokenInfo } = require("../src/shared/balances");
-    let answer;
-    lookupTokenInfo.mockImplementationOnce(
-        () =>
-            new Promise((resolve) => {
-                answer = resolve;
-            }),
-    );
-    boot.node("settings-addtoken-address").value = NEW_TOKEN_ADDRESS;
-    const adding = boot.click("btn-settings-addtoken-manual");
-    await boot.click("btn-settings");
-
-    // Another write holds the lock, so the switch's save waits for it.
-    let releaseLock;
-    const lockHeld = navigator.locks.request(
-        "autistmask",
-        () =>
-            new Promise((resolve) => {
-                releaseLock = resolve;
-            }),
-    );
-    const select = boot.node("settings-network");
-    select.value = "sepolia";
-    const switching = Promise.all(select.listeners.change.map((fn) => fn()));
-    await boot.settle();
-
-    answer({ symbol: "NEW", decimals: 18, name: "New Token" });
-    await boot.settle();
-    releaseLock();
-    await lockHeld;
-    await switching;
-    await adding;
-
     const stored = boot.storage.read("autistmask");
     expect(stored.networkId).toBe("sepolia");
     expect(stored.trackedTokens).toEqual([]);
-    expect(stored.networkTrackedTokens.mainnet).toEqual([
+    expect(stored.networkTrackedTokens.mainnet).toEqual([MAINNET_TOKEN]);
-        {
-            address: NEW_TOKEN_ADDRESS,
-            symbol: "NEW",
-            decimals: 18,
-            name: "New Token",
-        },
-    ]);
 });
 
 describe("Back after a switch from the Settings gear", () => {

tests/uniswap.test.js

@@ -4380,9 +4380,10 @@ describe("uniswap decoder", () => {
         expect(detail(result, "Min. received").value).toBe("2.0000 USDC");
     });
 
-    // A zero balance check sets neither Token Out nor the minimum. The route
+    // With no minimum stated before it, a zero balance check is what sets the
-    // pays only the WRAP_ETH's WETH, to the router, where it stays.
+    // output side, and it guarantees nothing. No step pays anyone, so the
-    test("a zero balance check after a WRAP_ETH into the router names no output token and no minimum", () => {
+    // minimum is not said to be received.
+    test("a zero balance check with no earlier minimum states no minimum", () => {
         const data = buildExecute(
             solidityPacked(["uint8", "uint8"], [0x0b, 0x0e]),
             [
@@ -4395,16 +4396,9 @@ describe("uniswap decoder", () => {
         const result = uniswap.decode(data, ROUTER_ADDR, "0x1", {}, USER_ADDR);
         expect(result).not.toBeNull();
 
-        expect(detail(result, "Token Out").value).toBe(
+        expect(detail(result, "Token Out").value).toContain("USDT");
-            "Unknown (not named in the calldata)",
+        expect(detail(result, "Min. paid out").value).toBe(
-        );
+            "None (no minimum guaranteed)",
-        expect(detail(result, "Min. paid out")).toBeUndefined();
-        expect(detail(result, "Min. received")).toBeUndefined();
-        expect(detail(result, "Paid to").value).toBe(
-            "The router, where it stays (no later step pays it out)",
-        );
-        expect(detail(result, "Token moved into the router").address).toBe(
-            WETH_ADDR,
         );
     });
 

tests/uniswapRecipient.test.js

@@ -688,62 +688,6 @@ describe("an UNWRAP_WETH makes the output ETH only when the router holds it", ()
         ]);
     });
 
-    // The same route, then a balance check of the sender's USDC with a zero
-    // minimum. The check guarantees nothing, so Token Out stays ETH
-    // (https://git.eeqj.de/sneak/AutistMask/issues/649).
-    test("the same route, then a zero balance check of USDC, still reads as ETH with no minimum", () => {
-        const result = decode(
-            execute(
-                v4Swap(
-                    SWAP_USDT_FOR_WETH,
-                    SETTLE_USDT,
-                    take(WETH, MSG_SENDER, (ONE_WETH * 6n) / 10n),
-                    take(WETH, ADDRESS_THIS),
-                ),
-                unwrapWeth(MSG_SENDER),
-                balanceCheck(USDC, 0n),
-            ),
-        );
-        expect(result.name).toBe("Swap USDT → ETH");
-        expect(detail(result, "Token Out").value).toBe("ETH");
-        expect(labels(result)).toEqual([
-            "Protocol",
-            "Token In",
-            "Amount",
-            "Token Out",
-            "Steps",
-            "Deadline",
-        ]);
-    });
-
-    // A PERMIT2_TRANSFER_FROM moves the sender's WETH into the router. An
-    // UNWRAP_WETH pays that WETH to the user as ETH. A zero balance check of
-    // USDC sets neither Token Out nor the minimum, before the UNWRAP_WETH or
-    // after it (https://git.eeqj.de/sneak/AutistMask/issues/649).
-    test.each([
-        {
-            kind: "before the UNWRAP_WETH",
-            steps: [balanceCheck(USDC, 0n), unwrapWeth(MSG_SENDER)],
-        },
-        {
-            kind: "after the UNWRAP_WETH",
-            steps: [unwrapWeth(MSG_SENDER), balanceCheck(USDC, 0n)],
-        },
-    ])(
-        "WETH moved into the router and unwrapped, with a zero balance check of USDC $kind, reads as ETH with no minimum",
-        ({ steps }) => {
-            const result = decode(
-                execute(
-                    permit2TransferFrom(WETH, ADDRESS_THIS, ONE_WETH),
-                    ...steps,
-                ),
-            );
-            expect(detail(result, "Token Out").value).toBe("ETH");
-            expect(detail(result, "Min. received")).toBeUndefined();
-            expect(detail(result, "Min. paid out")).toBeUndefined();
-        },
-    );
-
     // A TAKE the decoder cannot read may pay part of the WETH to the user.
     test("one V4 step paying WETH to the router beside a TAKE that cannot be read, then an UNWRAP_WETH, reads as ETH with no minimum", () => {
         const result = decode(
@@ -2876,16 +2820,17 @@ describe("the allow-revert flag", () => {
         },
     );
 
-    test("a BALANCE_CHECK_ERC20 with the flag, and no minimum before it, names no output token and no minimum", () => {
+    test("a BALANCE_CHECK_ERC20 with the flag, and no minimum before it, states none", () => {
         const check = balanceCheck(WETH, ONE_WETH);
         expect(detail(decode(execute(check)), "Min. paid out").value).toBe(
             "1.0000 WETH",
         );
 
         const withFlag = decode(execute(flagged(check)));
-        expect(detail(withFlag, "Token Out").value).toBe(UNNAMED);
+        expect(detail(withFlag, "Token Out").address).toBe(WETH);
-        expect(detail(withFlag, "Min. paid out")).toBeUndefined();
+        expect(detail(withFlag, "Min. paid out").value).toBe(
-        expect(detail(withFlag, "Min. received")).toBeUndefined();
+            "None (no minimum guaranteed)",
+        );
     });
 
     // Only the routers from UniversalRouterV2 on let a PERMIT2_PERMIT fail.