fix: the address screen shows a token just added at its fetched balance, not 0.0000 (closes #516)

A balance refresh that returns now draws the balances on AddressDetail or
AddressToken again when that screen is up, not only the wallet list; their
transaction lists are left alone. Every add path on AddToken and
SettingsAddToken tracks a token through one step, trackToken(), which also
lists it in the new stored field tokensNotFetched: its line reads `quantity
unknown` instead of 0.0000 until a refresh that started with it tracked has
fetched every address's token balances, even if the popup closes first. To
tell an address whose token balances the explorer did not return, the refresh
takes them off its copy of the wallets before fetching.

Model: opus-5-5

README.md

@@ -461,13 +461,15 @@ address, the transaction assertions run against the raw signed transaction
 captured at `eth_sendRawTransaction` rather than against anything the extension
 reported, rejecting each prompt is required to return a rejection to the page
 rather than hang or resolve, a network switch request is required to leave the
-stored network unchanged and send no `chainChanged` until it is approved, a
+stored network unchanged and send no `chainChanged` until it is approved, the
-network switch in Settings is required to send the page `chainChanged` with the
+popup open all along is required to show the `[TESTNET]` banner once a switch to
-new chain id, a prompt raised while another approval window has focus is
+Sepolia is approved and to drop it once the switch back is, a network switch in
-required to open a window of its own, and the password is required to be absent
+Settings is required to send the page `chainChanged` with the new chain id, a
-from every message the approval window sends to the background — with the
+prompt raised while another approval window has focus is required to open a
-message that would carry it required to be present, so that check cannot pass by
+window of its own, and the password is required to be absent from every message
-observing nothing. That last one is the standing floor under
+the approval window sends to the background — with the message that would carry
+it required to be present, so that check cannot pass by observing nothing. That
+last one is the standing floor under
 [#157](https://git.eeqj.de/sneak/AutistMask/issues/157).
 
 The limits of that coverage and of the rest of the Chrome suite, none of them
@@ -500,9 +502,12 @@ papered over:
   forced by clicking Reveal and the settings gear in one page task, which a
   person cannot do; the case a person can hit, the first decrypt after the popup
   opens while libsodium is still loading, is not driven.
-- Approval windows open at 1280x720 whatever size the extension asks for, so
+- Approval windows open at 1280x720 whatever size the extension asks for. The
-  whether an approval screen fits its window is checked in the Firefox suite
+  site-connection prompt and the transaction approval are checked for sideways
-  only.
+  scrolling at 396x600 by sizing the page itself for that measurement only, and
+  the rest of each test runs at 1280x720. That leaves out the window's frame and
+  the page widening its window, so whether an approval screen fits its window is
+  checked in the Firefox suite only.
 
 Any test that drives a failure path on purpose declares the `console.error` it
 is about to provoke, via `errors.expect()`. That is not a mute: the declaration
@@ -600,9 +605,10 @@ suite), wallet creation through the UI, the Add Token screen, and the dApp round
 trips — `eth_requestAccounts`, `personal_sign`, `wallet_switchEthereumChain`
 rejected and then approved, `eth_sendTransaction`, and a closed approval window
 rejecting with EIP-1193 4001 — driven through the real content script,
-background page and approval windows. The `personal_sign` prompt is also
+background page and approval windows. The popup open all along is required to
-required to fit its window without scrolling sideways, with the extension's
+show the `[TESTNET]` banner once the switch to Sepolia is approved and to drop
-pages at 170% zoom.
+it once the switch back is. The `personal_sign` prompt is also required to fit
+its window without scrolling sideways, with the extension's pages at 170% zoom.
 
 The suite lives in `tests/e2e/firefox/`. Its WebDriver client (`driver.js`) has
 **no npm dependencies at all**: it is built on global `fetch` and
@@ -1126,13 +1132,15 @@ scale is not an approximation but a different number — 1,000 units of a
 6-decimal token formatted at 18 decimals reads `0.000000001` — on the screen
 whose only job is to state what is being authorized. Both amount paths of that
 screen take this rule: the ERC-20 `transfer`/`approve` line
-(`src/popup/views/approval.js`) and the swap's `Amount` and `Min. received`
+(`src/popup/views/approval.js`) and the swap's `Amount`, `Min. received`,
-lines (`src/shared/uniswap.js`). The token permission warning on the signature
+`Moved from the sender` and `Permit2 allowance` lines and the `Paid to` line of
-screen takes the same rule for its amounts. An unbounded allowance or permit
+a move into the router (`src/shared/uniswap.js`). The token permission warning
-needs no scale to describe and is still shown as `Unlimited`. A source's answer
+on the signature screen takes the same rule for its amounts. An unbounded
-counts only if it is a whole number from 0 to 80: `decimals()` returns a
+allowance or permit needs no scale to describe and is still shown as
-`uint8`, but `formatUnits()` cannot format more than 80 decimal places, so a
+`Unlimited`. A source's answer counts only if it is a whole number from 0 to 80:
-token that reports 81 to 255 is shown as one whose scale nothing knows.
+`decimals()` returns a `uint8`, but `formatUnits()` cannot format more than 80
+decimal places, so a token that reports 81 to 255 is shown as one whose scale
+nothing knows.
 
 The rule holds only if nothing invents a scale UPSTREAM of it. Those three
 sources are read as authoritative, so a value written into one of them cannot be
@@ -1165,8 +1173,8 @@ fetched, without that cross-address check, and shows the row's figure.
 **Decoded amount lines on the transaction approval screen:** the `Amount` line
 of a decoded ERC-20 call, and the `Amount` and `Min. received` lines of a
 decoded swap (see TxApproval below; `Min. received` reads `Min. paid out` unless
-only the user is paid, see Transaction Decoding), do not always read as a
+only the user is paid and no allowance goes to a spender other than the router,
-number. They can read:
+see Transaction Decoding), do not always read as a number. They can read:
 
 - A formatted quantity, e.g. `17.1900 USDT`, when the token's scale is known:
   truncated to four decimals, with the floor and the zero cases described above.
@@ -1176,28 +1184,22 @@ number. They can read:
 - `Unlimited`: on the ERC-20 `Amount` line, an `approve` of the `uint256`
   maximum, an unbounded allowance. On the swap's `Amount` line, any amount at or
   above the `uint160` maximum, whichever step set the line: a `PERMIT2_PERMIT`
-  amount at that maximum, which is an unbounded permit, or a V2 or V3 exact-in,
+  amount at that maximum, which is an unbounded permit, or a V2 or V3 exact-in
-  V2 exact-out or `WRAP_ETH` amount that large, which is not an allowance. The
+  or exact-out or `WRAP_ETH` amount that large, which is not an allowance. The
   router's whole-balance value, `CONTRACT_BALANCE` (`2^255`), is one such
   amount.
-- `Up to <amount>`: the swap's `Amount` line, when the transaction has a V2
+- `Up to <amount>`: the swap's `Amount` line, when the transaction has a V2 or
-  exact-out step, whichever step set the line, including the `WRAP_ETH` of a
+  V3 exact-out step, whichever step set the line, including the `WRAP_ETH` of a
   swap paid in ETH and a `PERMIT2_PERMIT`. The swap spends at most that figure,
   not necessarily all of it; the wait, success and error screens show it with
   the same words. `Unlimited`, `All available (V4 open delta)` and
   `Whatever an earlier step sent to the pair (V2 already paid)` keep their
-  wording. When a V2 exact-out step sets `Min. received`, that line shows its
+  wording. When a V2 or V3 exact-out step sets `Min. received`, that line shows
-  `amountOut`, the exact amount it buys.
+  its `amountOut`, the exact amount it buys.
 - `All available (V4 open delta)`: the swap's `Amount` line, when the amount it
   shows is a V4 exact-in `amountIn` of zero. V4 reads that zero as "use the
-  whole open delta", so the calldata states no quantity. The line shows the
+  whole open delta", so the calldata states no quantity. Transaction Decoding
-  amount of the step that sets the input side: the last `PERMIT2_PERMIT` step if
+  below gives the steps whose amounts the line shows.
-  there is one, otherwise the first V2 or V3 exact-in, V2 exact-out, `WRAP_ETH`
-  or V4 swap step that names an input token or amount. A V4 step with a swap
-  action sets the input side when no earlier step set it, even when it names
-  neither, as described below. A V2 exact-out step gives its `amountInMax`, and
-  a V4 swap step the `amountIn` of the swap action that spends its input
-  currency.
 - `Whatever an earlier step sent to the pair (V2 already paid)`: the swap's
   `Amount` line, when the amount it shows is a V2 exact-in `amountIn` of zero.
   The router reads that zero as "the pair already holds the input tokens": the
@@ -1247,12 +1249,40 @@ only when no earlier step set it. It finds each side by three rules:
    `Amount` or `Min. received`. A side they did not name is unknown, and the
    step sets it as unknown with no figure.
 
+Under each of these rules, when the user pays the step any of the input
+currency, its `Amount` is instead what the user pays it of that currency when
+the decoder knows that amount, and otherwise there is none (see Transaction
+Decoding). So a step whose USDT-for-USDC swap action could not be read, with a
+`SETTLE` of 400 USDT paid by the user, reads `Amount 400.0000 USDT`.
+
 A V4 step with no swap action sets only the sides its `SETTLE`, `SETTLE_ALL`,
 `TAKE` or `TAKE_ALL` names.
 
-An `UNWRAP_WETH` step makes `Token Out` ETH only when the output side is WETH,
+An `UNWRAP_WETH` step makes `Token Out` ETH only when no step set the output
-on mainnet or Sepolia, or when no step set the output side; a WETH
+side, or when the output side is WETH, on mainnet or Sepolia, that the step that
-`Min. received` figure then reads in ETH. Otherwise `Token Out` and
+set it paid to the router and that the router still holds when the `UNWRAP_WETH`
+runs (Transaction Decoding below gives what the router holds). The router
+unwraps only the WETH it holds, so WETH that step paid to the user, or to anyone
+else, stays WETH: a swap that pays the router WETH, then a swap that pays the
+user WETH, then an unwrap, shows WETH with the second swap's minimum. The
+minimum reads in ETH only when that step paid all its WETH to the router and
+every step between it and the `UNWRAP_WETH` is one the decoder read of these: a
+`PERMIT2_PERMIT`, a `BALANCE_CHECK_ERC20`, or a `SWEEP`, `TRANSFER`,
+`PAY_PORTION` or `PAY_PORTION_FULL_PRECISION` of a token other than WETH, but
+not of ETH to a WETH contract, which pays the router WETH. None of these can
+take WETH out of the router or pay anyone WETH; the decoder treats every other
+step as one that may. Otherwise the swap shows ETH with no minimum, as it does
+after a V4 step that `TAKE`s some of its WETH to the user and the rest to the
+router, or that pays the router WETH beside a payout the decoder cannot read,
+and with a WETH interface fee paid by `PAY_PORTION` before the `UNWRAP_WETH`:
+the decoder does not count how much of that step's minimum reaches the
+`UNWRAP_WETH`, nor read the `UNWRAP_WETH`'s own minimum. When an `UNWRAP_WETH`
+of that WETH pays the router, or its recipient cannot be read, the router may
+hold the ETH, and a later step may pay it out as WETH, as a `WRAP_ETH` of it to
+the user does: after any later step but those listed, the swap shows WETH with
+no minimum. Once the swap shows no minimum, or shows WETH this way, no later
+step, a later `UNWRAP_WETH` included, brings back the minimum or ETH; only a
+later step that sets the output side sets it anew. Otherwise `Token Out` and
 `Min. received` keep the output side's own token and figure, whether the swap
 was paid in ETH or in a token: a V2 exact-out swap that buys USDC and then
 unwraps the WETH it did not spend shows USDC. The token permission warning on
@@ -1366,7 +1396,9 @@ lists, the send-screen token selector, the address total and the remove-address
 warning (`isBelowOneMillionth()` in `src/shared/amountDisplay.js`). The Send and
 confirmation screens show it when its token is the one being sent. Tracked
 tokens with a zero balance are listed as well while "Show tracked tokens with
-zero balance" is on.
+zero balance" is on; a token just added on AddToken or SettingsAddToken whose
+balance no refresh has fetched yet is listed there as `quantity unknown` (see
+AddToken).
 
 #### Stored state and its version
 
@@ -1376,6 +1408,19 @@ carries a `schemaVersion` — `STATE_SCHEMA_VERSION` in
 `saveState()` and the background's `updateState()` both do, so whichever context
 wrote last, the record says which build's shape it is in.
 
+Each write reads the record, changes it and writes it back, holding a lock from
+the read to the write: the browser's own (`navigator.locks`), taken through
+`withLock()` in `src/shared/browserApi.js`. Every page of the extension and its
+background share it, except a page in a Firefox private window, which Firefox
+gives locks of its own (see https://git.eeqj.de/sneak/AutistMask/issues/646).
+The popup's `saveState()`, the background's `updateState()` and the
+StateRecovery reset all take it, so among the pages and the background that
+share it, no write lands between another write's read and its write, where it
+would be lost. Chrome has it from version 69, older than any Chrome that runs a
+Manifest V3 extension, in pages and in the service worker; Firefox from version
+96, older than the 115 `manifest/firefox.json` declares. Where it is missing, a
+write fails rather than going ahead without it.
+
 Version 1 is the shape that shipped before versions existed, so a stored record
 with no `schemaVersion` is version 1 rather than a defect: it loads normally and
 is migrated in place by being stamped on the first write. An upgrade never shows
@@ -1524,20 +1569,36 @@ such as an edit typed into Settings and not yet saved. Home is the one screen
 "Back" always re-renders, so the wallet list reflects anything that changed
 while the user was away from it.
 
-A network switch in Settings leaves every screen beneath Settings showing the
+The popup refreshes balances every ten seconds while it is open
-previous network, so after it "Back" behaves as in a reopened popup: every
+(`doRefreshAndRender()` in `src/popup/index.js`). Each refresh that returns
-screen on the stack counts as not yet rendered, and the stack is cut at the
+draws the wallet list again and, when AddressDetail or AddressToken is up, that
-first screen that cannot be rendered from saved state, such as Send or AddToken,
+screen's USD total and balance lines; its transaction list is left alone. No
-or at AddressToken for any token but the native one, because that token was
+other screen is drawn again by a refresh, DeleteAddress and its balance lines
-picked on the previous network. The cut stack is saved with the switch, so a
+included.
-popup closed straight after it and reopened onto Settings lands in the same
+
-place. "Back" then renders the screen it lands on for the new network, and
+A network switch leaves every screen on the page showing the previous network.
-anything typed there and not saved, which belonged to the previous network, is
+The user makes it in Settings, or approves a site's request and the background
-dropped. ConfirmTx, WaitTx, SuccessTx, ErrorTx and TransactionDetail are
+saves it. Any other popup open meanwhile takes the switch from the stored
-rendered instead for the network of the transaction they show: the network it
+record, even one saved while it was opening, and never switches the network
-was reviewed on for ConfirmTx, and the network it was sent on for the others.
+itself. A switch the user picks in its Settings while it takes one is made after
-Without a wallet the stack is not cut, because it starts at Welcome, which shows
+it, not overwritten by it. An approval window does not take the switch. After
-nothing from a network.
+the switch, whichever way the page got it, "Back" behaves as in a reopened
+popup: every screen on the stack counts as not yet rendered, and the stack is
+cut at the first screen that cannot be rendered from saved state, such as Send
+or AddToken, or at AddressToken for any token but the native one, because that
+token was picked on the previous network and is no longer selected. The cut
+stack is saved with the popup's new network, so a popup closed straight after
+and reopened lands in the same place. The screen on top is drawn again for the
+new network: Settings in place, and any other screen as a reopened popup draws
+it, so Home takes the place of one that cannot be rendered from saved state or
+of AddressToken for a token no longer selected. "Back" then renders the screen
+it lands on for the new network, and anything typed there and not saved, which
+belonged to the previous network, is dropped. ConfirmTx, WaitTx, SuccessTx,
+ErrorTx and TransactionDetail are rendered instead for the network of the
+transaction they show: the network it was reviewed on for ConfirmTx, and the
+network it was sent on for the others. Without a wallet the stack is not cut and
+only Settings is drawn again, because the stack starts at Welcome, and Welcome
+and AddWallet show nothing from a network.
 
 Every screen that holds secret material in the page registers a cleanup with
 `onViewLeave()` (`src/popup/views/helpers.js`), which `showView()` runs on every
@@ -1986,7 +2047,11 @@ view would leave a wallet one click from deletion.
     - Type: transaction classification — one of: Native ETH Transfer, ERC-20
       Token Transfer, Swap, Token Approval, Contract Call, Contract Creation. A
       transfer with a token contract is an ERC-20 Token Transfer whatever symbol
-      the token reports.
+      the token reports. A call named `execute` or `multicall` is a Swap, here
+      and on its history row, only when it was sent to one of the Universal
+      Router addresses Uniswap publishes for the network it was sent on (see
+      Transaction Decoding); sent to any other contract, its history row shows
+      the method name and this line reads Contract Call.
     - Status: "Success" or "Failed"
     - From: blockie + color dot + full address (tap to copy) + etherscan link;
       ENS name if available
@@ -2022,7 +2087,14 @@ view would leave a wallet one click from deletion.
     - "Add" button
 - **Transitions**:
     - "Add" (valid contract) → tracks the token, pops the stack, and re-renders
-      **AddressDetail**
+      **AddressDetail**. The token's balance is not known until a balance
+      refresh that started with it tracked has fetched every address's token
+      balances; until then its balance line reads `quantity unknown`, never
+      `0.0000`, unless the explorer had already listed a holding of it. That
+      holds after the popup is closed and opened again, as the tokens still
+      waiting for a fetch are stored with the profile. A refresh that returns
+      draws AddressDetail's balances again (see Navigation), so the fetched
+      balance shows without the screen being reopened
     - "Add" with a token already tracked, a scam-listed address, or a failed
       contract lookup → flash message, no screen change
     - "Add", then a network switch in Settings before the contract lookup
@@ -2050,8 +2122,11 @@ view would leave a wallet one click from deletion.
       none, and the tokens tracked on that network, and sends `chainChanged`
       with the new chain id to every open tab. A token is tracked only on the
       network it was added on, because a contract address names a token on one
-      network only. Choosing the network already active changes nothing and
+      network only. Switching also clears every address's balances. A balance
-      sends nothing
+      refresh, by the popup or the background, stores what it fetched only if
+      the stored network is still the one it fetched on when it returns, so the
+      previous network's balances never reach the new one. Choosing the network
+      already active changes nothing and sends nothing
     - Ethereum RPC: endpoint URL input + "Save" button (validated against
       `eth_chainId` before being saved)
     - Blockscout API: endpoint URL input + "Save" button (validated against
@@ -2296,7 +2371,9 @@ view would leave a wallet one click from deletion.
       add path
 - **Transitions**:
     - Any of the add paths shown, on success → adds the token and shows an
-      "Added SYMBOL" flash message (no screen change)
+      "Added SYMBOL" flash message (no screen change). Until its balance is
+      fetched, its balance line reads `quantity unknown`, as after "Add" on
+      AddToken
     - A duplicate, a scam-listed address, or a failed contract lookup → flash
       message, no screen change
     - "Add" by contract address, then a network switch in Settings before the
@@ -2379,10 +2456,13 @@ view would leave a wallet one click from deletion.
     - Site origin (bold, scheme and port included) + "wants to send a
       transaction"
     - Decoded action (if calldata is recognized): action name, token details,
-      amounts, what each `PERMIT2_TRANSFER_FROM` moves and where to, steps,
+      amounts, what each swap step spends that the `Amount` line does not give,
-      deadline, and unless a swap pays only the From address, a `Paid to` line
+      what each `PERMIT2_TRANSFER_FROM` moves and where to, what each
-      for each other address it pays, or saying that a token stays in the router
+      `PERMIT2_PERMIT` whose amount is not the `Amount` figure, and each
-      or who it pays is unknown (see Transaction Decoding)
+      `PERMIT2_PERMIT_BATCH`, lets its spender take, steps, deadline, and unless
+      a swap pays only the From address, a `Paid to` line for each other address
+      it pays, or saying that a token stays in the router or who it pays is
+      unknown (see Transaction Decoding)
     - From: color dot + full address + etherscan link
     - Contract: color dot + full address + etherscan link, token symbol label if
       known; for a contract creation, the same sentence as on WaitTx
@@ -2395,6 +2475,11 @@ view would leave a wallet one click from deletion.
     - Raw data: full calldata displayed inline (shown if present)
     - Password input and an error line
     - "Confirm" / "Reject" buttons
+- **Behavior**: Every etherscan link on the screen opens the explorer of the
+  network the transaction was populated on, whichever network is active. The
+  Value and Network fee lines each give the USD value of the exact amount at the
+  price on that network, as on ConfirmTx: none for a testnet transaction or one
+  on a chain id that names no network.
 - **Transitions**:
     - "Confirm" (correct password) → decrypts and signs the transaction it was
       shown, exactly as shown, hands the signed transaction to the background to
@@ -3005,29 +3090,35 @@ Currently supported:
   Router addresses Uniswap publishes for the network: on TxApproval the network
   the transaction is for, on TransactionDetail the network it was sent on. The
   same calldata sent to any other address is shown as raw data. Decodes Permit2,
-  V2/V3/V4 swaps, wrap/unwrap, and balance checks. A V4 swap action is read only
+  V2/V3/V4 swaps, wrap/unwrap, and balance checks. A V3 swap step's path is read
-  in the parameter shape deployed on mainnet and Sepolia, not in the newer one
+  as the router reads it: a `V3_SWAP_EXACT_IN` path runs from the token it
-  on `v4-periphery` `main`, which adds a `minHopPriceX36` field. An action in
+  spends to the token it buys, and a `V3_SWAP_EXACT_OUT` path from the token it
-  any other shape is not read, and its step is listed as
+  buys to the token it spends, so that step's input token is its path's last
-  `V4 Swap (could not be decoded)`. Each step is named and read as the command
+  token and its output token the first. The router reads a path as one token
-  that the release of the router at that address runs for its command type, as
+  address followed by whole hops of a 3-byte fee and a token address, and
-  that release's `contracts/libraries/Commands.sol` names it. The decoder reads
+  ignores any bytes after the last hop, so the decoder does not read a path with
-  the type from the command byte with the mask that router uses: `0x1f` for
+  such bytes. A V4 swap action is read only in the parameter shape deployed on
-  `UniversalRouterV1`, `0x3f` for `UniversalRouterV1_2_V2Support` and
+  mainnet and Sepolia, not in the newer one on `v4-periphery` `main`, which adds
-  `UniversalRouterV2`, and `0x7f` for `UniversalRouterV2_1_1` and
+  a `minHopPriceX36` field. An action in any other shape is not read, and its
-  `UniversalRouterV2_1_2`. The allow-revert flag (`0x80`) therefore does not
+  step is listed as `V4 Swap (could not be decoded)`. Each step is named and
-  change the command a step is read as. Releases run different commands for some
+  read as the command that the release of the router at that address runs for
-  types: on `UniversalRouterV1` and `UniversalRouterV1_2_V2Support`, `0x10` to
+  its command type, as that release's `contracts/libraries/Commands.sol` names
-  `0x13` are NFT commands, where the later routers run `V4_SWAP`,
+  it. The decoder reads the type from the command byte with the mask that router
-  `V3_POSITION_MANAGER_PERMIT`, `V3_POSITION_MANAGER_CALL` and
+  uses: `0x1f` for `UniversalRouterV1`, `0x3f` for
-  `V4_INITIALIZE_POOL`. The decoder does not read those routers' NFT commands,
+  `UniversalRouterV1_2_V2Support` and `UniversalRouterV2`, and `0x7f` for
-  and lists each by its name there, for example `Seaport` for `SEAPORT` (`0x10`
+  `UniversalRouterV2_1_1` and `UniversalRouterV2_1_2`. The allow-revert flag
-  on `UniversalRouterV1`). A type a release names no command for is listed by
+  (`0x80`) therefore does not change the command a step is read as. Releases run
-  its number, for example `Command 0x0e` on `UniversalRouterV1`, which has no
+  different commands for some types: on `UniversalRouterV1` and
-  `BALANCE_CHECK_ERC20` and reverts on it. The router reverts the whole
+  `UniversalRouterV1_2_V2Support`, `0x10` to `0x13` are NFT commands, where the
-  transaction when a step fails, unless the step's command byte has that flag
+  later routers run `V4_SWAP`, `V3_POSITION_MANAGER_PERMIT`,
-  set and its command is one the router lets fail, as each release's
+  `V3_POSITION_MANAGER_CALL` and `V4_INITIALIZE_POOL`. The decoder does not read
-  `contracts/base/Dispatcher.sol` shows: on `UniversalRouterV2`,
+  those routers' NFT commands, and lists each by its name there, for example
+  `Seaport` for `SEAPORT` (`0x10` on `UniversalRouterV1`). A type a release
+  names no command for is listed by its number, for example `Command 0x0e` on
+  `UniversalRouterV1`, which has no `BALANCE_CHECK_ERC20` and reverts on it. The
+  router reverts the whole transaction when a step fails, unless the step's
+  command byte has that flag set and its command is one the router lets fail, as
+  each release's `contracts/base/Dispatcher.sol` shows: on `UniversalRouterV2`,
   `UniversalRouterV2_1_1` and `UniversalRouterV2_1_2`, `PERMIT2_PERMIT`,
   `PERMIT2_PERMIT_BATCH`, `BALANCE_CHECK_ERC20`, `V3_POSITION_MANAGER_PERMIT`,
   `V3_POSITION_MANAGER_CALL`, `V4_INITIALIZE_POOL`, `V4_POSITION_MANAGER_CALL`
@@ -3090,37 +3181,43 @@ Currently supported:
   as a swap paid in ETH does, but only when that amount is not
   `CONTRACT_BALANCE` and the router held no WETH from an earlier step when the
   `WRAP_ETH` ran: after two `WRAP_ETH`s of 0.5 ETH into the router, a swap of 1
-  WETH from it reads as leaving the WETH there. The router pays a `SETTLE` of
+  WETH from it reads as leaving the WETH there. A V2 or V3 exact-out step paid
-  `OPEN_DELTA` (zero) only what its step still owes of that token when the
+  from the router spends an amount the calldata does not state, at most its
-  `SETTLE` runs, so one from the router counts as spending the amounts the
+  `amountInMax`, so the decoder counts it as spending nothing the router holds.
-  step's swap actions state they spend of that token only when every action in
+  A `SETTLE` of `OPEN_DELTA` (zero), and a `SETTLE_ALL`, pay only what the step
-  the step could be read, every swap action names the token it spends and the
+  still owes of their token when they run. The decoder takes that to be the
-  token it buys (a swap action with an empty path swaps nothing), the `SETTLE`
+  amounts the step's swap actions state they spend of that token only when every
-  is the step's only `SETTLE` or `SETTLE_ALL` of that token and comes after
+  action in the step could be read, every swap action names the token it spends
-  every swap action, no swap action buys that token, and the swap actions that
+  and the token it buys (a swap action with an empty path swaps nothing), the
-  spend it state a quantity together; otherwise it counts as spending nothing.
+  `SETTLE` or `SETTLE_ALL` is the step's only `SETTLE` or `SETTLE_ALL` of that
-  So the rest of a V4 `SETTLE` of more than its swap spends, taken to the
+  token and comes after every swap action, no swap action buys that token, no
-  router, the WETH of a `WRAP_ETH`, and a token a swap pays the router on the
+  `TAKE`, `TAKE_ALL` or `TAKE_PORTION` in the step takes it (a `TAKE` of a
-  way to the output, each stays in the router when later steps do not spend all
+  stated amount adds to what the step owes), and the swap actions that spend it
-  of it, where anyone can take it in a later transaction. The router sends ETH
+  state a quantity together; otherwise it does not know the amount, and such a
-  as written, so a `TRANSFER` of `CONTRACT_BALANCE` of ETH always reverts and
+  `SETTLE` from the router counts as spending nothing. So the rest of a V4
-  pays out nothing. A step paying a token to the V2 pair that the very next step
+  `SETTLE` of more than its swap spends, taken to the router, the WETH of a
-  spends, as a V2 exact-in of that token whose `amountIn` is `ALREADY_PAID`
+  `WRAP_ETH`, and a token a swap pays the router on the way to the output, each
-  (zero) or `CONTRACT_BALANCE`, is a hop, not a payout: Uniswap's mixed routes
+  stays in the router when later steps do not spend all of it, where anyone can
-  pay the next V2 pair directly, and the router enforces that swap's own
+  take it in a later transaction. The router sends ETH as written, so a
-  minimum. The decoder checks that the address paid is that pair, deriving it
+  `TRANSFER` of `CONTRACT_BALANCE` of ETH always reverts and pays out nothing. A
-  from the V2 factory and pair init code hash the network's routers were
+  step paying a token to the V2 pair that the very next step spends, as a V2
-  deployed with and the first two tokens of that step's path; a payment to any
+  exact-in of that token whose `amountIn` is `ALREADY_PAID` (zero) or
-  other address is named. (Sepolia's `UniversalRouterV1_2_V2Support` was
+  `CONTRACT_BALANCE`, is a hop, not a payout: Uniswap's mixed routes pay the
-  deployed with placeholders for both values, so no V2 swap step can succeed on
+  next V2 pair directly, and the router enforces that swap's own minimum. The
-  that router.) Every other payment counts, in whichever step and of whatever
+  decoder checks that the address paid is that pair, deriving it from the V2
-  token, a share of the output included: an interface fee paid to another
+  factory and pair init code hash the network's routers were deployed with and
-  address by `PAY_PORTION`, `TRANSFER` or `TAKE_PORTION` is named, and the
+  the first two tokens of that step's path; a payment to any other address is
-  minimum reads `Min. paid out`, because the swap's minimum includes the fee.
+  named. (Sepolia's `UniversalRouterV1_2_V2Support` was deployed with
-  The minimum reads `Min. received` only when some step pays the transaction's
+  placeholders for both values, so no V2 swap step can succeed on that router.)
-  sender (the From address on TxApproval, the sender the explorer reports on
+  Every other payment counts, in whichever step and of whatever token, a share
-  TransactionDetail) and no `Paid to` line is shown. `Paid to` lines after
+  of the output included: an interface fee paid to another address by
-  `Token Out` name each other address paid; one reads
+  `PAY_PORTION`, `TRANSFER` or `TAKE_PORTION` is named, and the minimum reads
+  `Min. paid out`, because the swap's minimum includes the fee. The minimum
+  reads `Min. received` only when some step pays the transaction's sender (the
+  From address on TxApproval, the sender the explorer reports on
+  TransactionDetail), no `Paid to` line is shown, and no permit or batch grants
+  an allowance to a spender other than the router (see below). `Paid to` lines
+  after `Token Out` name each other address paid; one reads
   `The bridge, which pays the deposit's recipient on another network` for a
   bridge deposit; one reads, for example,
   `The router, 2000.0000 USDT from the sender (later steps may not spend all of it)`
@@ -3132,24 +3229,136 @@ Currently supported:
   name); and one more reads `Unknown (could not be decoded)` when a step that
   may pay an address went unread. When no step pays anyone, a single line reads
   `Unknown (not named in the calldata)`. Wherever there is a `Paid to` line, the
-  minimum reads `Min. paid out`. After the `Amount` line (after `Token In` when
+  minimum reads `Min. paid out`. The `Amount` line gives the total the steps
-  there is none), each `PERMIT2_TRANSFER_FROM` but one into the router, in step
+  take of `Token In`, from the step that sets the input side on: the first V2 or
-  order, gives three lines: `Moved from the sender`, the amount it moves, for
+  V3 exact-in or exact-out, `WRAP_ETH` or V4 swap step that names an input token
-  example `1000000.0000 USDT`; `Token moved`, giving the token's address as the
+  or amount. A V4 step with a swap action sets the input side when no earlier
-  `Token In` line does; and `Moved to`, which reads
+  step set it, even when it names neither (see Display Consistency). That step
+  counts its own amount, whoever pays it: a V2 or V3 exact-out step its
+  `amountInMax`, and a V4 step what it takes of its input token from the user's
+  wallet, as below, or, when the user pays it none of that token, the `amountIn`
+  of the swap action that spends it. Each later V2 or V3 exact-in or exact-out
+  step whose `payerIsUser` is true takes its amount, found in the same way, from
+  the user's wallet. Every V4 step, with a swap action or without, takes from
+  the user's wallet what its `SETTLE`s paid by the user (`payerIsUser` true) and
+  its `SETTLE_ALL`s pay, for each token on its own; what the step that sets the
+  input side takes of any other token counts as a later step's take. A `SETTLE`
+  of any amount but `OPEN_DELTA` pays that amount, and a `SETTLE` of
+  `OPEN_DELTA` or a `SETTLE_ALL` pays what the step owes, as above. So a V4 step
+  that swaps 400 USDT, with a `SETTLE` of 5,000 USDT paid by the user and the
+  rest taken to another address, reads `5000.0000 USDT`. A later step paid from
+  the router spends what the router holds and takes nothing, and so does a V2
+  exact-in whose `amountIn` is `ALREADY_PAID`. A later take of `Token In` is
+  added to the total while both are quantities: a V3 exact-in of 600 USDT and a
+  V2 exact-in of 400 USDT, both paid by the user, read `1000.0000 USDT`. When
+  the decoder does not know a take's amount, the total is not known and there is
+  no `Amount` line. A `PERMIT2_PERMIT` names `Token In` only when its amount,
+  `Unlimited` included, stands as the `Amount` figure in place of the total,
+  which it does only in the plain shape of Uniswap's own routes: it comes before
+  the step that sets the input side, it is the only `PERMIT2_PERMIT` in the
+  transaction and there is no `PERMIT2_PERMIT_BATCH`, its spender is the router,
+  the router may not let it fail, no step before it takes its token, a
+  `PERMIT2_TRANSFER_FROM` of it included, or a token the decoder does not know,
+  and the decoder reads every step after it in full. Permit2 then lets the
+  router take no more of the token than that amount, so the permit covers every
+  take of it. A step before the permit takes under whatever allowance the router
+  already had, so it may take more than the permit's amount, which would then
+  read lower than what leaves the user's wallet: a `PERMIT2_TRANSFER_FROM` of
+  2,000 USDT into the router, then a permit of 600 USDT to the router and a V3
+  exact-in of 2,000 USDT paid from the router, read `Amount 2000.0000 USDT`. A
+  later permit or batch may raise what Permit2 lets the router take, and so may
+  a step the decoder does not read in full: a command the decoder does not read
+  (listed at the end of this section), a step whose input it cannot read, in
+  whole or in part, and a step it fails on. Every other `PERMIT2_PERMIT`, before
+  the step that sets the input side or after it, leaves `Token In` and the
+  `Amount` line as they read with no permit, unless it lets a spender other than
+  the router take `Token In` (see below): a permit of 5,000 DAI to another
+  address and then a V3 exact-in of 600 USDT read `Swap USDT → USDC` with
+  `Amount 600.0000 USDT`, and so do that exact-in and then a permit of 5,000 DAI
+  to the router. When a permit's amount stands and the step that sets the input
+  side spends a token other than the permit's, or one the decoder does not know,
+  that step's amount gets lines of its own, unless it states no amount and the
+  user pays it none of its input token. Each take the total does not count gives
+  three lines after the `Amount` line (after `Token In` when there is none): one
+  of a token other than `Token In`; one of `Token In` after an amount that is
+  not a quantity (a V4 open delta, `ALREADY_PAID`, which keep their wording on
+  the `Amount` line, or no stated amount, as of a V4 exact-out step); and one
+  whose amount the decoder does not know. When there is no `Amount` line, each
+  take the total counts gets them too, so that every amount the decoder reads is
+  shown: the amount the step that sets the input side states, when it is a
+  quantity and the user pays that step (a V2 or V3 step whose `payerIsUser` is
+  true, a V4 step the user pays some of its input token, or a `WRAP_ETH`, whose
+  ETH comes from the transaction's value), and each later take of `Token In`
+  added to it. A step that sets the input side and is paid from the router takes
+  nothing from the user's wallet and gets none. A `PERMIT2_PERMIT` the decoder
+  cannot read, then V3 exact-ins of 600 USDT and 400 DAI paid by the user, give
+  lines for both amounts. When the step that sets the input side states no
+  amount, the user pays it some of its input token, and there is no `Amount`
+  line, that step gets them too whenever another take's lines give a figure, or
+  a `PERMIT2_TRANSFER_FROM` of its token gives one, on the lines below or, into
+  the router, on its `Paid to` line, so that figure cannot read as all that
+  leaves. When it states no amount and the user pays it none of its input token,
+  as when the router pays it, that step takes none of that token from the user's
+  wallet and never gets them, with a permit or without. They come in step order,
+  except that the step that sets the input side comes first when it has them,
+  followed, when there is no `Amount` line, by the other takes the total counts:
+  `Moved from the sender`, its amount, worded as the `Amount` line words one, or
+  `Unknown (could not be decoded)` when the decoder does not know it;
+  `Token moved`, giving the token's address as the `Token In` line does; and
+  `Moved to`, which reads `The swap step that spends it`. A token the decoder
+  does not know gives the `Moved from the sender` line alone. A step may also
+  take from the user's wallet what the decoder did not read: a V4 step whose
+  input or one of whose `SETTLE`s or `SETTLE_ALL`s it cannot read, which the
+  router still runs; a V2 or V3 exact-in or exact-out step or a
+  `PERMIT2_TRANSFER_FROM` whose input it cannot read, such as a V3 step whose
+  path is shorter than one token address or has bytes after its last hop; every
+  `PERMIT2_TRANSFER_FROM_BATCH`; every `EXECUTE_SUB_PLAN`, wherever it stands;
+  and every step it fails on. Each such step gives one `Moved from the sender`
+  line among those, reading `Unknown (could not be decoded)`. That line, or any
+  line for a token the decoder does not know, leaves no `Amount` line, whose
+  figure might be too low, and such a step before a `PERMIT2_PERMIT` keeps the
+  permit's amount from standing. Then each `PERMIT2_TRANSFER_FROM` but one into
+  the router, in step order, gives three lines: `Moved from the sender`, the
+  amount it moves, for example `1000000.0000 USDT`; `Token moved`, giving the
+  token's address as the `Token In` line does; and `Moved to`, which reads
   `The V2 pair the next swap spends` for a hop and `The sender` for `address(1)`
   on every router but `UniversalRouterV1`, and otherwise gives the address. A
   move into the router needs none of them, because its `Paid to` line and
   `Token moved into the router` line already give the amount, the token and
-  where it goes, and so its amount is shown once. These lines change neither the
+  where it goes, and so its amount is shown once. Every `PERMIT2_PERMIT` whose
-  `Paid to` lines nor the minimum's label. A step goes unread when its recipient
+  amount does not stand as the `Amount` figure, before the step that sets the
-  does not decode as an address, or when it is a command the decoder does not
+  input side or after it, gives three lines, in step order, after those for each
-  read: every command other than `PERMIT2_PERMIT`, `PERMIT2_TRANSFER_FROM`,
+  `PERMIT2_TRANSFER_FROM`: `Permit2 allowance`, its amount, for example
-  `V2_SWAP_EXACT_IN`, `V2_SWAP_EXACT_OUT`, `V3_SWAP_EXACT_IN`, `V4_SWAP`,
+  `5000.0000 DAI`, or `Unlimited` for Permit2's maximum; `Allowance token`,
-  `SWEEP`, `TRANSFER`, `PAY_PORTION`, `PAY_PORTION_FULL_PRECISION`,
+  giving the token's address as the `Token In` line does; and
-  `ACROSS_V4_DEPOSIT_V3`, `WRAP_ETH`, `UNWRAP_WETH` and `BALANCE_CHECK_ERC20`
+  `Allowance spender`, the address it lets take the token. Only a permit whose
-  (`V3_SWAP_EXACT_OUT`, `PERMIT2_TRANSFER_FROM_BATCH`, `EXECUTE_SUB_PLAN` and
+  amount stands gives none: the `Amount` line gives its amount, `Token In` its
-  the NFT commands among them), or a type its release names no command for.
+  token, and its spender is the router. Each allowance a `PERMIT2_PERMIT_BATCH`
+  grants, one for each token it names, all for its one spender, gives the same
+  three lines, in step order with those of each `PERMIT2_PERMIT`. A
+  `PERMIT2_PERMIT` or `PERMIT2_PERMIT_BATCH` whose input the decoder cannot
+  read, such as one whose token or spender word has a nonzero top byte, may let
+  any spender take any amount of any token: it gives one `Permit2 allowance`
+  line alone, reading `Unknown (could not be decoded)`. These lines change no
+  `Paid to` line: a permit or batch pays nobody. But code that a step runs, such
+  as a V4 pool's hook or a token's own code, can call a spender other than the
+  router, which can then take up to its allowance from the user's wallet before
+  the transaction ends. So an allowance to any spender but the router, or a
+  permit or batch the decoder cannot read, makes the minimum read
+  `Min. paid out`, and when its token is `Token In`, or the decoder does not
+  know its token or `Token In`, it leaves no `Amount` line, whose figure might
+  be too low: a permit of 5,000 USDT to another address and then a V3 exact-in
+  of 600 USDT read with no `Amount` line, and the 600 USDT gets lines of its
+  own. A step goes unread when its recipient does not decode as an address, when
+  it is a V3 swap step whose path is shorter than one token address or has bytes
+  after its last hop, or when it is a command the decoder does not read: every
+  command other than `PERMIT2_PERMIT`, `PERMIT2_PERMIT_BATCH`,
+  `PERMIT2_TRANSFER_FROM`, `V2_SWAP_EXACT_IN`, `V2_SWAP_EXACT_OUT`,
+  `V3_SWAP_EXACT_IN`, `V3_SWAP_EXACT_OUT`, `V4_SWAP`, `SWEEP`, `TRANSFER`,
+  `PAY_PORTION`, `PAY_PORTION_FULL_PRECISION`, `ACROSS_V4_DEPOSIT_V3`,
+  `WRAP_ETH`, `UNWRAP_WETH` and `BALANCE_CHECK_ERC20`
+  (`PERMIT2_TRANSFER_FROM_BATCH`, `EXECUTE_SUB_PLAN` and the NFT commands among
+  them), or a type its release names no command for.
 
 ### Non-Goals Forever
 

package.json

@@ -13,6 +13,11 @@
         "fmt": "prettier --write .",
         "fmt-check": "prettier --check ."
     },
+    "jest": {
+        "setupFiles": [
+            "<rootDir>/tests/support/navigatorLocks.js"
+        ]
+    },
     "devDependencies": {
         "@eslint/js": "10.0.1",
         "@tailwindcss/cli": "4.3.1",

src/background/index.js

@@ -1379,6 +1379,13 @@ const RECENT_BALANCE_REFRESH_MS = Math.floor(BALANCE_REFRESH_PERIOD_MS / 2);
 // balances that came back — by address, onto whatever storage holds NOW.
 // Applying by address rather than writing the array back is what keeps a
 // wallet or address added, renamed or deleted during the round trip.
+//
+// Nothing is applied when the network stored NOW is not the one the refresh
+// ran on. A network switch during the round trip cleared every address's
+// balances (applyChainSwitchFields()), and the previous network's must not come
+// back over them (https://git.eeqj.de/sneak/AutistMask/issues/577).
+// lastBalanceRefresh is left as the switch set it, so the next tick refreshes
+// the new network.
 async function backgroundRefresh() {
     const s = await getState();
     const now = Date.now();
@@ -1402,6 +1409,7 @@ async function backgroundRefresh() {
     }
 
     await updateState((fresh) => {
+        if (fresh.networkId !== s.networkId) return;
         for (const wallet of fresh.wallets) {
             for (const addr of wallet.addresses || []) {
                 const got = refreshed.get(String(addr.address).toLowerCase());

src/background/state.js

@@ -16,17 +16,20 @@
 //                     across any number of awaits and no concurrent work can
 //                     move it.
 //   updateState(fn)   read fresh, apply fn to that fresh record, write it
-//                     back — all inside a queue, so two background writes
+//                     back — all holding the lock every write of the stored
-//                     never interleave, and the read is one storage round trip
+//                     record takes, so no other write lands in between, by
-//                     ahead of the write rather than a page lifetime ahead of
+//                     the background or by any page except a page in a
-//                     it (which is what made the popup's saveState() need a
+//                     Firefox private window (README, "Stored state and its
+//                     version"). The read is one storage round trip ahead of
+//                     the write rather than a page lifetime ahead of it
+//                     (which is what made the popup's saveState() need a
 //                     per-field merge against a baseline at all).
 //
 // A handler that must both read and write therefore does its network work
 // against a snapshot it owns, and applies the RESULT inside updateState().
 // It never publishes an object other in-flight work is holding.
 
-const { storageGet, storageSet } = require("../shared/browserApi");
+const { storageGet, storageSet, withLock } = require("../shared/browserApi");
 const { normalizePersisted } = require("../shared/persistedState");
 const {
     STATE_SCHEMA_VERSION,
@@ -51,11 +54,6 @@ async function getState() {
     return normalizePersisted(result.autistmask);
 }
 
-// Serializes the read-modify-write turns below. Two of them interleaved would
-// each read before the other wrote, and the second write would carry the first
-// one's fields back to their pre-turn values.
-let updateQueue = Promise.resolve();
-
 async function updateStateOnce(mutate) {
     const s = await getState();
     await mutate(s);
@@ -70,27 +68,22 @@ async function updateStateOnce(mutate) {
 
 // Apply `mutate` to a record read fresh from storage and write the result
 // back. `mutate` receives a detached, normalized profile and mutates it in
-// place; it may be async, but it must not do anything slow — the window
+// place; it may be async, but it must not do anything slow. The write is the
-// between the read and the write is the window in which another context's
+// WHOLE record, which is safe only because the lock (withLock() in
-// write is lost, and keeping it to one storage round trip is what makes a
+// src/shared/browserApi.js) is held from the read to the write: two
-// whole-record write safe here. Concretely: the write is the WHOLE record, so
+// background turns, or a turn and a page's save, never interleave
-// a popup write that lands inside that window is reverted, in every field, by
+// (https://git.eeqj.de/sneak/AutistMask/issues/641). Every page's save waits
-// the record this turn read before it. That is accepted because the window is
+// while it is held, except a page in a Firefox private window, which Firefox
-// one round trip long and the popup is not writing while the worker is;
+// gives locks of its own (README, "Stored state and its version").
-// widening it is what would make it a real hazard.
 //
 // `mutate` must also not call updateState() itself, directly or through
-// anything it awaits: the queue is strictly serial, so the inner turn waits on
+// anything it awaits: the inner turn waits for the lock the outer one holds,
-// the outer one, which is waiting on the inner one. That deadlocks the whole
+// and the outer one is waiting on the inner one. That deadlocks every write of
-// background, not just the caller. Mutate the record you were handed.
+// the stored record, not just the caller. Mutate the record you were handed.
 //
 // Resolves with the record that was written.
 function updateState(mutate) {
-    const turn = updateQueue.then(() => updateStateOnce(mutate));
+    return withLock("autistmask", () => updateStateOnce(mutate));
-    // The queue must advance even when a turn rejects, or every update after
-    // it queues behind a promise that never settles.
-    updateQueue = turn.catch(() => {});
-    return turn;
 }
 
 module.exports = { getState, updateState };

src/popup/index.html

@@ -90,7 +90,7 @@
                 <div id="add-wallet-section-mnemonic">
                     <!-- The die button shares the instruction's row: on a row
                          of its own it pushes Import below the fold at
-                         360x600. -->
+                         396x600. -->
                     <div class="mb-2 flex justify-between items-start gap-2">
                         <p>
                             Enter your 12 or 24 word recovery phrase below, or
@@ -212,7 +212,7 @@
                     />
                 </div>
                 <!-- The error line sits beside Import, not above it: at
-                     360x600 the button already starts near the bottom of
+                     396x600 the button already starts near the bottom of
                      the popup, and a line of its own would push it below
                      the fold. The longest error fits on one line here. -->
                 <div class="flex items-center gap-2">

src/popup/index.js

@@ -5,12 +5,14 @@ const {
     state,
     saveState,
     onSaveFailure,
+    takeStoredNetwork,
     loadState,
 } = require("../shared/state");
 const { StateUnusableError } = require("../shared/stateSchema");
 const { log, setRuntimeDebug } = require("../shared/log");
 const { refreshPrices } = require("../shared/prices");
 const { refreshBalances } = require("../shared/balances");
+const { clearPopupCaches } = require("../shared/chainSwitch");
 const {
     $,
     showView,
@@ -22,6 +24,7 @@ const {
 } = require("./views/helpers");
 const { applyTheme } = require("./theme");
 const {
+    onStorageChanged,
     tabsGetCurrent,
     tabsGetZoom,
     windowsGetCurrent,
@@ -68,24 +71,83 @@ let refreshInFlight = false;
 // the recovery screen: there is no profile left to refresh.
 let refreshTimer = null;
 
+// The refresh writes into a copy of the wallets. Inside the save, under the
+// lock, its results are copied onto the address records in `state` only if the
+// network it ran on is still the active one, on this page and in the stored
+// record; the background's switch, after the user approves a site's request,
+// reaches this page only after the stored record (followNetworkSwitch() below).
+// A switch while the refresh ran cleared every address's balances
+// (applyChainSwitchFields() in src/shared/chainSwitchFields.js), and the
+// previous network's must not come back over them
+// (https://git.eeqj.de/sneak/AutistMask/issues/577). A dropped refresh is not
+// recorded as done. Results are copied by address, so an address added or
+// removed meanwhile is left as it is.
+//
+// Once the save is done, the wallet list is drawn again, and so are the
+// balances on AddressDetail or AddressToken when that is the screen up. No
+// other screen is drawn again, DeleteAddress and its balance lines included.
 async function doRefreshAndRender() {
     if (refreshInFlight) return;
     refreshInFlight = true;
     try {
+        const networkId = state.networkId;
+        // The tracked tokens this refresh asks the explorer about. A token
+        // added on AddToken after this point is not among them, so this
+        // refresh does not count as having fetched it.
+        const tokens = state.trackedTokens.map((t) => t.address.toLowerCase());
+        const wallets = structuredClone(state.wallets);
+        // Taken off the copy, so that an address whose token balances the
+        // explorer did not return comes back without any and keeps its
+        // stored ones.
+        for (const wallet of wallets) {
+            for (const addr of wallet.addresses) delete addr.tokenBalances;
+        }
         await Promise.all([
             refreshPrices(),
             refreshBalances(
-                state.wallets,
+                wallets,
                 state.rpcUrl,
                 state.blockscoutUrl,
                 state.trackedTokens,
-                state.networkId,
+                networkId,
                 pageClosed.signal,
             ),
         ]);
-        state.lastBalanceRefresh = Date.now();
+        const refreshed = new Map();
-        await saveState();
+        let allTokenBalancesFetched = true;
+        for (const wallet of wallets) {
+            for (const addr of wallet.addresses) {
+                refreshed.set(addr.address, addr);
+                if (addr.tokenBalances === undefined) {
+                    allTokenBalancesFetched = false;
+                }
+            }
+        }
+        await saveState((stored) => {
+            if (state.networkId !== networkId) return false;
+            if (stored.networkId !== networkId) return false;
+            for (const wallet of state.wallets) {
+                for (const addr of wallet.addresses) {
+                    const got = refreshed.get(addr.address);
+                    if (!got) continue;
+                    for (const key of ["balance", "ensName", "tokenBalances"]) {
+                        if (got[key] !== undefined) addr[key] = got[key];
+                    }
+                }
+            }
+            // Each token this refresh asked about is now fetched for every
+            // address.
+            if (allTokenBalancesFetched) {
+                state.tokensNotFetched = state.tokensNotFetched.filter(
+                    (token) => !tokens.includes(token),
+                );
+            }
+            state.lastBalanceRefresh = Date.now();
+            return true;
+        });
         renderWalletList();
+        if (state.currentView === "address") addressDetail.renderBalances();
+        if (state.currentView === "address-token") addressToken.renderBalance();
     } catch (e) {
         // Every call site fires this and walks away — the boot below, the ten
         // second interval, and eight views through ctx — so it must never
@@ -116,6 +178,7 @@ const ctx = {
     renderWalletList,
     doRefreshAndRender,
     startRefresh,
+    restoreView,
     pageClosed: pageClosed.signal,
     showAddWalletView: () => {
         pushCurrentView();
@@ -183,6 +246,28 @@ function fallbackView() {
     showView("main");
 }
 
+// When the background saves a network switch, once the user approves a site's
+// request, or another popup page saves one, this page follows the stored
+// record. It takes the network the record names as a save reads it, holding
+// the lock, so no later save of this page writes the previous network back, and
+// then leaves the page as a switch in Settings leaves it. This page's own
+// switch in Settings is made under the lock as well (onChainSwitch() in
+// src/shared/chainSwitch.js), so a record naming a network other than this
+// page's always holds a switch saved elsewhere, and a switch the user picks
+// here while this waits for the lock is made after it.
+async function followNetworkSwitch() {
+    let switched = false;
+    // A failed save is reported by saveState() itself: see onSaveFailure().
+    await saveState((stored) => {
+        if (stored.networkId === state.networkId) return false;
+        settings.cutViewStack();
+        takeStoredNetwork(stored);
+        clearPopupCaches();
+        switched = true;
+    }).catch(() => {});
+    if (switched) settings.showNewNetwork();
+}
+
 // The background opens the approval window as wide as the page, but the
 // browser counts the window's frame in that width, and a screen taller than
 // the window takes a vertical scrollbar out of it too. So once the screen is
@@ -220,7 +305,7 @@ async function widenApprovalWindow() {
 async function init() {
     // First, before anything can save: showView() saves on every navigation
     // without awaiting, so a save that fails from here on has somewhere to be
-    // reported rather than being swallowed by the save queue
+    // reported rather than reaching only the console
     // (https://git.eeqj.de/sneak/AutistMask/issues/362). Registered ahead of
     // the approval-window branch below too, since that window saves as well.
     //
@@ -327,6 +412,17 @@ async function init() {
     settingsAddToken.init(ctx);
     deleteAddress.init(ctx);
 
+    // Only a record naming a network other than this page's is followed: the
+    // one this page's own switch in Settings saves names the network it
+    // already has, and a record naming none is no switch.
+    onStorageChanged((changes) => {
+        const written = changes.autistmask && changes.autistmask.newValue;
+        if (!written || !written.networkId) return;
+        if (written.networkId !== state.networkId) followNetworkSwitch();
+    });
+    // A switch saved since loadState() above, before there was a listener.
+    followNetworkSwitch();
+
     if (!state.hasWallet) {
         showView("welcome");
     } else {

src/popup/viewRouter.js

@@ -39,8 +39,8 @@ function markViewRendered(view) {
 }
 
 // Begin a fresh page-load scope. The popup gets one by being loaded, and
-// asks for one when the user switches the network, because every screen
+// asks for one after a network switch, because every screen then on the page
-// then on the page shows the previous network (views/settings.js); the
+// shows the previous network (showNewNetwork() in views/settings.js); the
 // unit tests, which simulate several page loads against one module
 // instance, ask for one too.
 function resetRenderedViews() {

src/popup/views/addToken.js

@@ -1,4 +1,11 @@
-const { $, showView, showFlash, escapeHtml, goBack } = require("./helpers");
+const {
+    $,
+    showView,
+    showFlash,
+    escapeHtml,
+    goBack,
+    trackToken,
+} = require("./helpers");
 const { getTopTokens } = require("../../shared/tokenList");
 const { state, saveState, currentNetwork } = require("../../shared/state");
 const { lookupTokenInfo } = require("../../shared/balances");
@@ -72,7 +79,7 @@ function init(ctx) {
                 return;
             }
             log.infof("Adding token", info.symbol, contractAddr);
-            state.trackedTokens.push({
+            trackToken({
                 address: contractAddr,
                 symbol: info.symbol,
                 decimals: info.decimals,

src/popup/views/addressDetail.js

@@ -65,11 +65,25 @@ function show() {
     });
     $("address-line").dataset.full = addr.address;
     attachCopyHandlers($("address-line"));
-    const usdTotal = formatAddressTotal(getAddressValue(addr));
-    $("address-usd-total").innerHTML = escapeHtml(usdTotal) || " ";
     const ensEl = $("address-ens");
     // ENS is now shown inside renderAddressHtml, hide the separate element
     ensEl.classList.add("hidden");
+    renderBalances();
+    renderSendTokenSelect(addr);
+    $("tx-list").innerHTML =
+        '<div class="text-muted text-xs py-1">Loading...</div>';
+    showView("address");
+    loadTransactions(addr.address);
+}
+
+// The USD total and the balance list. Drawn again by each balance refresh
+// that returns while this screen is up (doRefreshAndRender() in
+// src/popup/index.js), which leaves the rest of the screen as it is.
+function renderBalances() {
+    const addr =
+        state.wallets[state.selectedWallet].addresses[state.selectedAddress];
+    const usdTotal = formatAddressTotal(getAddressValue(addr));
+    $("address-usd-total").innerHTML = escapeHtml(usdTotal) || "&nbsp;";
     $("address-balances").innerHTML = balanceLinesForAddress(
         addr,
         state.trackedTokens,
@@ -83,11 +97,6 @@ function show() {
                 ctx.showAddressToken();
             });
         });
-    renderSendTokenSelect(addr);
-    $("tx-list").innerHTML =
-        '<div class="text-muted text-xs py-1">Loading...</div>';
-    showView("address");
-    loadTransactions(addr.address);
 }
 
 let loadedTxs = [];
@@ -280,4 +289,4 @@ function init(_ctx) {
     exportPrivkey.init();
 }
 
-module.exports = { init, show };
+module.exports = { init, show, renderBalances };

src/popup/views/addressToken.js

@@ -48,37 +48,18 @@ function show() {
     const addr = wallet.addresses[state.selectedAddress];
     const ai = state.selectedAddress;
     const tokenId = state.selectedToken;
-
-    // Determine token symbol and balance
-    let symbol, amount, price;
     const knownToken = TOKEN_BY_ADDRESS.get(tokenId.toLowerCase());
-    if (tokenId === "ETH") {
+    currentSymbol =
-        symbol = nativeCurrency();
+        tokenId === "ETH"
-        amount = parseFloat(addr.balance || "0");
+            ? nativeCurrency()
-        price = getPrice("ETH");
+            : resolveSymbol(tokenId, addr.tokenBalances, state.trackedTokens);
-    } else {
-        const tb = (addr.tokenBalances || []).find(
-            (t) => t.address.toLowerCase() === tokenId.toLowerCase(),
-        );
-        symbol = resolveSymbol(
-            tokenId,
-            addr.tokenBalances,
-            state.trackedTokens,
-        );
-        // null when the scale is unknown: no quantity to show, and none to
-        // price. balanceLine() states that rather than printing 0.0000.
-        amount = tb ? unknownableAmount(tb.balance) : 0;
-        price = getPrice(symbol);
-    }
-
-    currentSymbol = symbol;
 
     $("address-token-title").textContent =
         wallet.name +
         " \u2014 Address " +
         (ai + 1) +
         " \u2014 " +
-        displaySymbol(symbol);
+        displaySymbol(currentSymbol);
 
     // Blockie
     const blockieEl = $("address-token-jazzicon");
@@ -100,13 +81,7 @@ function show() {
     $("address-token-line").dataset.full = addr.address;
     attachCopyHandlers($("address-token-line"));
 
-    // USD total for this token only
+    renderBalance();
-    const usdVal = price && amount !== null ? amount * price : null;
-    const usdStr = formatUsd(usdVal);
-    $("address-token-usd-total").innerHTML = escapeHtml(usdStr) || " ";
-
-    // Single token balance line (no tokenId — not clickable here)
-    $("address-token-balance").innerHTML = balanceLine(symbol, amount, price);
 
     // Token contract details (ERC-20 only)
     const contractInfo = $("address-token-contract-info");
@@ -168,6 +143,44 @@ function show() {
     loadTransactions(addr.address, tokenId);
 }
 
+// The USD total and the balance line of the selected token. Drawn again by
+// each balance refresh that returns while this screen is up
+// (doRefreshAndRender() in src/popup/index.js), which leaves the rest of the
+// screen as it is.
+function renderBalance() {
+    const addr =
+        state.wallets[state.selectedWallet].addresses[state.selectedAddress];
+    const tokenId = state.selectedToken;
+    let amount, price;
+    if (tokenId === "ETH") {
+        amount = parseFloat(addr.balance || "0");
+        price = getPrice("ETH");
+    } else {
+        const id = tokenId.toLowerCase();
+        const tb = (addr.tokenBalances || []).find(
+            (t) => t.address.toLowerCase() === id,
+        );
+        // null when the scale is unknown, or when no refresh has fetched a
+        // token just added: no quantity to show, and none to price.
+        // balanceLine() states that rather than printing 0.0000.
+        if (tb) amount = unknownableAmount(tb.balance);
+        else amount = state.tokensNotFetched.includes(id) ? null : 0;
+        price = getPrice(currentSymbol);
+    }
+
+    // USD total for this token only
+    const usdVal = price && amount !== null ? amount * price : null;
+    const usdStr = formatUsd(usdVal);
+    $("address-token-usd-total").innerHTML = escapeHtml(usdStr) || " ";
+
+    // Single token balance line (no tokenId — not clickable here)
+    $("address-token-balance").innerHTML = balanceLine(
+        currentSymbol,
+        amount,
+        price,
+    );
+}
+
 async function loadTransactions(address, tokenId) {
     try {
         const rawTxs = await fetchRecentTransactions(
@@ -343,4 +356,4 @@ function init(_ctx) {
     });
 }
 
-module.exports = { init, show };
+module.exports = { init, show, renderBalance };

src/popup/views/approval.js

@@ -58,9 +58,15 @@ const { notify, runtimeApi, sendMessage } = require("../../shared/browserApi");
 
 const erc20Iface = new Interface(ERC20_ABI);
 
-function approvalAddressHtml(address) {
+// The link opens the explorer of the network with `chainId`, or of the active
+// network when none is given. A chain id that names no network has no
+// explorer, so the address is drawn without a link.
+function approvalAddressHtml(address, chainId) {
     const title = addressTitle(address, state.wallets);
-    return renderAddressHtml(address, { title });
+    if (chainId && !networkByChainId(chainId)) {
+        return renderAddressHtml(address, { title, noLink: true });
+    }
+    return renderAddressHtml(address, { title, chainId });
 }
 
 // The amount line for a decoded ERC-20 call. With a known scale it is the
@@ -225,10 +231,11 @@ function showTxFee(approvedTx) {
     const feePerGas = BigInt(approvedTx.maxFeePerGas || approvedTx.gasPrice);
     // Through formatFee(), as the confirmation screen's fee is, so the same
     // fee reads the same on both. In the native currency of the network shown
-    // above, as the value is.
+    // above, and at the price on it, as the value is.
     $("approve-tx-fee").textContent = formatFee(
         gasLimit * feePerGas,
         nativeCurrencyByChainId(approvedTx.chainId),
+        approvedTx.chainId,
     );
 
     let detail =
@@ -338,8 +345,14 @@ function showTxApproval(details) {
         };
     }
 
+    // Every address link on this screen opens the explorer of the network the
+    // transaction is for, which the Network line names, whichever network is
+    // active.
     $("approve-tx-origin").textContent = details.origin;
-    $("approve-tx-from").innerHTML = approvalAddressHtml(details.approvedFrom);
+    $("approve-tx-from").innerHTML = approvalAddressHtml(
+        details.approvedFrom,
+        approvedTx.chainId,
+    );
 
     // Show token symbol next to contract address if known on the network the
     // transaction is for
@@ -349,17 +362,18 @@ function showTxApproval(details) {
         if (symbol) {
             toHtml += `<div class="font-bold mb-1">${escapeHtml(symbol)}</div>`;
         }
-        toHtml += approvalAddressHtml(toAddr);
+        toHtml += approvalAddressHtml(toAddr, approvedTx.chainId);
         $("approve-tx-to").innerHTML = toHtml;
     } else {
         $("approve-tx-to").innerHTML = escapeHtml(CONTRACT_CREATION_TEXT);
     }
 
-    const ethValueFormatted = formatTxValue(
+    const ethValueFormatted = formatTxValue(ethValue);
-        formatEther(approvedTx.value || "0"),
+    // Priced from the exact value, not the four-decimal figure, at the price
-    );
+    // on the network the transaction is for, as the confirmation screen prices
-    const ethPrice = getPrice("ETH");
+    // its amount, so the same value reads the same on both.
-    const ethUsd = ethPrice ? parseFloat(ethValueFormatted) * ethPrice : null;
+    const ethPrice = getPrice("ETH", approvedTx.chainId);
+    const ethUsd = ethPrice ? parseFloat(ethValue) * ethPrice : null;
     const usdStr = formatUsd(ethUsd);
     // In the native currency of the network the transaction is for, which the
     // Network line names, not the active network's: the active network can
@@ -388,7 +402,10 @@ function showTxApproval(details) {
                 if (d.isToken) {
                     detailsHtml += `<div class="font-bold">${escapeHtml(tokenLabel(d.address, approvedTx.chainId) || "Unknown token")}</div>`;
                 }
-                detailsHtml += approvalAddressHtml(d.address);
+                detailsHtml += approvalAddressHtml(
+                    d.address,
+                    approvedTx.chainId,
+                );
             } else {
                 detailsHtml += `<div class="font-bold">${escapeHtml(d.value)}</div>`;
             }

src/popup/views/helpers.js

@@ -380,6 +380,18 @@ function balanceLine(symbol, amount, price, tokenId) {
     );
 }
 
+// Tracks `token` on the active network, as every add path on AddToken and
+// SettingsAddToken does, and lists it in `state.tokensNotFetched`: no refresh
+// has fetched its balance yet. An address with no balance row for it has no
+// known balance of it, so its line says the quantity is unknown rather than
+// 0.0000. doRefreshAndRender() in src/popup/index.js takes it off once a
+// refresh that started with it tracked has fetched every address's token
+// balances (https://git.eeqj.de/sneak/AutistMask/issues/516).
+function trackToken(token) {
+    state.trackedTokens.push(token);
+    state.tokensNotFetched.push(token.address.toLowerCase());
+}
+
 function balanceLinesForAddress(addr, trackedTokens, showZero) {
     let html = balanceLine(
         nativeCurrency(),
@@ -409,12 +421,13 @@ function balanceLinesForAddress(addr, trackedTokens, showZero) {
     }
     if (showZero && trackedTokens) {
         for (const t of trackedTokens) {
-            if (seen.has(t.address.toLowerCase())) continue;
+            const id = t.address.toLowerCase();
+            if (seen.has(id)) continue;
             html += balanceLine(
                 t.symbol,
-                0,
+                state.tokensNotFetched.includes(id) ? null : 0,
                 getPrice(t.symbol),
-                t.address.toLowerCase(),
+                id,
             );
         }
     }
@@ -786,6 +799,7 @@ module.exports = {
     flashCopyFeedback,
     balanceLine,
     balanceLinesForAddress,
+    trackToken,
     addressHoldsFunds,
     keyMaterialName,
     unknownableAmount,

src/popup/views/settings.js

@@ -38,6 +38,8 @@ const {
 
 const { notify, sendMessage } = require("../../shared/browserApi");
 
+let ctx;
+
 let versionClickCount = 0;
 let versionClickTimer = null;
 
@@ -243,7 +245,51 @@ async function renderSiteLists() {
     );
 }
 
-function init(ctx) {
+// A network switch, made by the user here or saved by the background once the
+// user approved a site's request (src/popup/index.js), leaves every screen on
+// the page showing the previous network. These two leave the page as README's
+// Screen Map describes, the first before the switch is saved, so that save
+// keeps the cut for a popup closed straight after, the second once `state`
+// holds the new network.
+//
+// The stack is cut at the first screen that cannot be rendered from saved
+// state, such as Send or AddToken, and at AddressToken unless it shows the
+// native token: any other token there was picked on the previous network, so
+// it is no longer selected either. Without a wallet the stack starts at
+// Welcome, which that cut would drop, and Welcome shows nothing from a network.
+function cutViewStack() {
+    if (!state.hasWallet) return;
+    if (state.selectedToken !== "ETH") {
+        const tokenView = state.viewStack.indexOf("address-token");
+        if (tokenView !== -1) {
+            state.viewStack = state.viewStack.slice(0, tokenView);
+        }
+        state.selectedToken = null;
+    }
+    state.viewStack = restorableStack(state.viewStack, state.currentView);
+}
+
+// Every screen counts as not yet rendered, so "Back" renders the one it lands
+// on for the new network. Settings on top is brought up to date in place;
+// any other screen is drawn again as a reopened popup draws it, which is Home
+// for one that cannot be rendered from saved state. Without a wallet any other
+// screen is Welcome or AddWallet, which show nothing from a network.
+function showNewNetwork() {
+    resetRenderedViews();
+    if (state.currentView === "settings") {
+        markViewRendered("settings");
+        $("settings-network").value = state.networkId;
+        $("settings-rpc").value = state.rpcUrl;
+        $("settings-blockscout").value = state.blockscoutUrl;
+        renderTrackedTokens();
+    } else if (state.hasWallet) {
+        ctx.restoreView();
+    }
+    updateDebugBanner(state.currentView);
+}
+
+function init(_ctx) {
+    ctx = _ctx;
     deleteWallet.init(ctx);
     showPhrase.init();
 
@@ -319,37 +365,18 @@ function init(ctx) {
 
     const networkSelect = $("settings-network");
     networkSelect.addEventListener("change", async () => {
+        // Whether `state` already has the network picked is asked only once
+        // the switch holds the lock: while an earlier pick waits for it,
+        // `state` still has the network before that pick, and a pick back to
+        // that network must still be made.
         const newId = networkSelect.value;
-        if (newId === state.networkId) return;
+        cutViewStack();
-        // The screens beneath Settings show the previous network, so Back
-        // finds them as it does in a reopened popup: each is rendered again
-        // when Back lands on it, and the stack is cut at the first one that
-        // cannot be rendered from saved state, such as Send or AddToken. It
-        // is cut at AddressToken too, unless that shows the native token: any
-        // other token there was picked on the previous network. Without a
-        // wallet the stack starts at Welcome, which that cut would drop, and
-        // Welcome shows nothing from a network. The cut comes before the
-        // switch so that the switch's save keeps it for a popup closed
-        // straight after.
-        if (state.hasWallet) {
-            const tokenView = state.viewStack.indexOf("address-token");
-            if (tokenView !== -1 && state.selectedToken !== "ETH") {
-                state.viewStack = state.viewStack.slice(0, tokenView);
-            }
-            state.viewStack = restorableStack(state.viewStack, "settings");
-        }
         const net = await onChainSwitch(newId);
+        if (!net) return;
         // Open pages are told by the background, as after a site's approved
         // switch request.
         notify({ type: "AUTISTMASK_NETWORK_CHANGED", chainId: net.chainId });
-        resetRenderedViews();
+        showNewNetwork();
-        // Settings itself, and the testnet banner above it, are brought up
-        // to date for the new network here.
-        markViewRendered("settings");
-        $("settings-rpc").value = state.rpcUrl;
-        $("settings-blockscout").value = state.blockscoutUrl;
-        renderTrackedTokens();
-        updateDebugBanner(state.currentView);
         showFlash("Switched to " + net.name + ".");
     });
 
@@ -484,4 +511,10 @@ function init(ctx) {
     });
 }
 
-module.exports = { init, show, renderSiteLists };
+module.exports = {
+    init,
+    show,
+    renderSiteLists,
+    cutViewStack,
+    showNewNetwork,
+};

src/popup/views/settingsAddToken.js

@@ -1,4 +1,11 @@
-const { $, showView, showFlash, escapeHtml, goBack } = require("./helpers");
+const {
+    $,
+    showView,
+    showFlash,
+    escapeHtml,
+    goBack,
+    trackToken,
+} = require("./helpers");
 const { getTopTokens } = require("../../shared/tokenList");
 const { state, saveState, currentNetwork } = require("../../shared/state");
 const { lookupTokenInfo } = require("../../shared/balances");
@@ -43,7 +50,7 @@ function renderTop10() {
                     decimals: parseInt(btn.dataset.decimals, 10),
                     name: btn.dataset.name || btn.dataset.symbol,
                 };
-                state.trackedTokens.push(token);
+                trackToken(token);
                 await saveState();
                 showFlash("Added " + token.symbol);
                 renderTop10();
@@ -110,7 +117,7 @@ function init(_ctx) {
             decimals: parseInt(opt.dataset.decimals, 10),
             name: opt.dataset.name || opt.dataset.symbol,
         };
-        state.trackedTokens.push(token);
+        trackToken(token);
         await saveState();
         showFlash("Added " + token.symbol);
         renderTop10();
@@ -156,7 +163,7 @@ function init(_ctx) {
                 return;
             }
             log.infof("Adding token", info.symbol, addr);
-            state.trackedTokens.push({
+            trackToken({
                 address: addr,
                 symbol: info.symbol,
                 decimals: info.decimals,

src/popup/views/stateRecovery.js

@@ -24,7 +24,11 @@
 // than written again locally so that tests/popupElementIds.test.js sees these
 // lookups and holds every id below against the markup.
 const { $, VIEWS } = require("./helpers");
-const { storageGet, storageRemove } = require("../../shared/browserApi");
+const {
+    storageGet,
+    storageRemove,
+    withLock,
+} = require("../../shared/browserApi");
 const { log } = require("../../shared/log");
 
 // Typed in full before anything is erased, in the same spirit as the wallet
@@ -137,7 +141,11 @@ async function resetProfile() {
         return;
     }
     try {
-        await storageRemove("autistmask");
+        // Under the lock every write of the stored record takes, so the erase
+        // cannot land between another write's read and its write and be undone.
+        // A page in a Firefox private window is the exception: Firefox gives
+        // it locks of its own (README, "Stored state and its version").
+        await withLock("autistmask", () => storageRemove("autistmask"));
     } catch (e) {
         log.errorf("state recovery: reset failed:", e);
         setFlash("The saved data could not be erased. Nothing was changed.");

src/shared/browserApi.js

@@ -31,6 +31,11 @@
 // Everything is resolved on use rather than captured at module load. The MV3
 // service worker is torn down and re-evaluated repeatedly, and the unit
 // suite installs its stubs on `global.chrome` around a require().
+//
+// The module also holds withLock(), a wrapper around the browser's
+// `navigator.locks`, which is in neither namespace. It sits beside
+// storageGet() and storageSet() because every write of the stored record
+// takes it.
 
 // The extension API namespace, preferring `browser.*` where it exists.
 //
@@ -219,6 +224,46 @@ function storageRemove(keys) {
     return Promise.resolve(storage.remove(keys));
 }
 
+/**
+ * Call `listener` after every write to `storage.local`, whether this page,
+ * another page or the background made it, with what the write changed, as the
+ * browser reports it: `{ [key]: { oldValue, newValue } }`.
+ *
+ * @param {function(Object): void} listener
+ */
+function onStorageChanged(listener) {
+    namespaceMember("storage").onChanged.addListener((changes, areaName) => {
+        if (areaName === "local") listener(changes);
+    });
+}
+
+/**
+ * Run `fn` while holding the browser's lock called `name`
+ * (`navigator.locks`), and settle as `fn` settles. Every page of the extension
+ * and its background share these locks, except a page in a Firefox private
+ * window (README, "Stored state and its version"), so while one of them holds
+ * `name` another asking for it waits, in the order they asked. The lock is let
+ * go when `fn` settles, whether it resolved or rejected.
+ *
+ * Every write of the stored record holds the lock named after its key,
+ * "autistmask", from its read to its write: saveState() in
+ * src/shared/state.js, updateState() in src/background/state.js, and the
+ * reset in src/popup/views/stateRecovery.js.
+ *
+ * @param {string} name
+ * @param {function(): Promise<*>} fn
+ * @returns {Promise<*>} what `fn` resolved with.
+ * @throws rejects, without running `fn`, where `navigator.locks` is absent.
+ */
+function withLock(name, fn) {
+    if (typeof navigator === "undefined" || !navigator.locks) {
+        return Promise.reject(
+            new Error("navigator.locks is not available in this context"),
+        );
+    }
+    return navigator.locks.request(name, () => fn());
+}
+
 // `storage.session`, the browser's session storage: what is kept there lasts
 // until the browser closes. It survives the background worker being stopped
 // and started again, which module-level variables do not (README, Background
@@ -353,6 +398,7 @@ module.exports = {
     getPlatformInfo,
     hasBrowserNamespace,
     notify,
+    onStorageChanged,
     runtimeApi,
     sendMessage,
     sessionStorageGet,
@@ -373,4 +419,5 @@ module.exports = {
     windowsGetLastFocused,
     windowsRemove,
     windowsUpdate,
+    withLock,
 };

src/shared/chainSwitch.js

@@ -1,8 +1,18 @@
-// Consolidated chain-switch handler for the popup.
+// The popup's network switch.
 //
-// Every state change required when the active network changes is
+// A network switch reaches the popup's `state` in one of two ways:
-// performed here so that callers (settings UI, future chain additions) all go
+//
-// through a single code path.
+// - onChainSwitch() below makes the switch the user picks in Settings, with
+//   applyChainSwitchFields() (chainSwitchFields.js).
+// - followNetworkSwitch() 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
+//   copyChainSwitchFields() (chainSwitchFields.js).
+//
+// Both change `state` inside a save, holding the lock, and both reset the
+// popup's own caches through clearPopupCaches(), so a reset added there
+// reaches both. A field applyChainSwitchFields() sets has to be copied by
+// copyChainSwitchFields() too.
 //
 // Adding a new chain (e.g. ETC) requires only a new entry in
 // networks.js — no per-caller wiring is needed.
@@ -20,22 +30,32 @@
 const { applyChainSwitchFields } = require("./chainSwitchFields");
 const { clearPrices } = require("./prices");
 
+// The popup's own caches a network switch resets. Prices are chain-specific
+// (testnet tokens are worthless, ETC has different pricing, etc.). In-memory
+// and per bundle, so this is the popup's own cache — the only context that
+// ever fills it.
+function clearPopupCaches() {
+    clearPrices();
+}
+
 // Switch the active chain and reset all chain-specific cached state.
-// Returns the network configuration object for the new chain.
+// Returns the network configuration object for the new chain, or null when
+// `state` already has that network once the save holds the lock, and nothing
+// is switched.
+//
+// `state` is switched inside the save that stores the switch, holding the
+// lock, so it is never switched while a follow of a switch saved elsewhere
+// waits for the lock (followNetworkSwitch() in src/popup/index.js): that
+// follow runs first, and this switch is made after it.
 async function onChainSwitch(newNetworkId) {
     const { state, saveState } = require("./state");
-
+    let net = null;
-    const net = applyChainSwitchFields(state, newNetworkId);
+    await saveState(() => {
-
+        if (state.networkId === newNetworkId) return false;
-    // --- price cache ---
+        net = applyChainSwitchFields(state, newNetworkId);
-    // Prices are chain-specific (testnet tokens are worthless,
+        clearPopupCaches();
-    // ETC has different pricing, etc.). In-memory and per bundle, so this is
+    });
-    // the popup's own cache — the only context that ever fills it.
-    clearPrices();
-
-    await saveState();
-
     return net;
 }
 
-module.exports = { onChainSwitch };
+module.exports = { onChainSwitch, clearPopupCaches };

src/shared/chainSwitchFields.js

@@ -7,7 +7,7 @@
 // the singleton and saves; 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 object it is
+// 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
 // what makes it usable on a record that has been read fresh from storage
 // microseconds earlier and is about to be written back.
@@ -76,4 +76,33 @@ function applyChainSwitchFields(s, newNetworkId) {
     return net;
 }
 
-module.exports = { applyChainSwitchFields };
+// Give `s` every field applyChainSwitchFields() sets, as `switched` holds it:
+// the popup takes a switch the background saved from the stored record this
+// way, rather than performing it again (takeStoredNetwork() in
+// src/shared/state.js). Balances are taken by address, and an address
+// `switched` does not have keeps none.
+function copyChainSwitchFields(s, switched) {
+    s.networkEndpoints = switched.networkEndpoints;
+    s.networkTrackedTokens = switched.networkTrackedTokens;
+    s.trackedTokens = switched.trackedTokens;
+    s.networkId = switched.networkId;
+    s.rpcUrl = switched.rpcUrl;
+    s.blockscoutUrl = switched.blockscoutUrl;
+    s.lastBalanceRefresh = switched.lastBalanceRefresh;
+    s.tokenHolderCache = switched.tokenHolderCache;
+    s.fraudContracts = switched.fraudContracts;
+
+    const stored = new Map();
+    for (const wallet of switched.wallets) {
+        for (const addr of wallet.addresses) stored.set(addr.address, addr);
+    }
+    for (const wallet of s.wallets) {
+        for (const addr of wallet.addresses) {
+            const got = stored.get(addr.address);
+            addr.balance = got ? got.balance : "0";
+            addr.tokenBalances = got ? got.tokenBalances : [];
+        }
+    }
+}
+
+module.exports = { applyChainSwitchFields, copyChainSwitchFields };

src/shared/persistedState.js

@@ -28,6 +28,13 @@ const DEFAULT_STATE = {
     // others are restored from when the active network changes. See
     // applyChainSwitchFields().
     networkTrackedTokens: {},
+    // Contract addresses, lowercased, of the tokens the user added that no
+    // balance refresh has fetched yet. trackToken() in
+    // src/popup/views/helpers.js adds one, and doRefreshAndRender() in
+    // src/popup/index.js takes it off. Stored, so a token added just before
+    // the popup closed still reads `quantity unknown` when it opens again
+    // (https://git.eeqj.de/sneak/AutistMask/issues/516).
+    tokensNotFetched: [],
     networkId: "mainnet",
     rpcUrl: DEFAULT_RPC_URL,
     blockscoutUrl: DEFAULT_BLOCKSCOUT_URL,
@@ -412,6 +419,8 @@ function normalizePersisted(saved) {
     // so a stored string walks through the `|| []` and a stored number walks
     // through an Array.isArray().
     out.fraudContracts = textList(saved.fraudContracts);
+    // Contract addresses too, read with `includes()` and `filter()`.
+    out.tokensNotFetched = textList(saved.tokensNotFetched);
     out.tokenHolderCache = structuredClone(saved.tokenHolderCache || {});
     out.theme = saved.theme || "system";
     out.debugMode = saved.debugMode !== undefined ? saved.debugMode : false;

src/shared/prices.js

@@ -38,11 +38,12 @@ function clearPrices() {
 }
 
 // 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.
+// active network when no chain id is given; null on testnet, on a chain id
+// that names no network, or for a symbol with no price.
 function getPrice(symbol, chainId) {
     const { currentNetwork } = require("./state");
     const network = chainId ? networkByChainId(chainId) : currentNetwork();
-    if (network.isTestnet) return null;
+    if (!network || network.isTestnet) return null;
     return prices[symbol] || null;
 }
 

src/shared/state.js

@@ -23,6 +23,7 @@
 // guarantee.
 
 const { networkById } = require("./networks");
+const { copyChainSwitchFields } = require("./chainSwitchFields");
 const {
     DEFAULT_STATE,
     PERSISTED_FIELDS,
@@ -35,7 +36,7 @@ const {
     migrationNeeded,
 } = require("./stateSchema");
 
-const { storageGet, storageSet } = require("./browserApi");
+const { storageGet, storageSet, withLock } = require("./browserApi");
 const { log } = require("./log");
 
 // The live record the proxy below guards. Everything inside this module reads
@@ -125,8 +126,10 @@ function currentNetwork() {
 }
 
 // The persisted fields as this page held them when its last loadState()
-// finished, or when its last successful saveState() began. saveState() diffs
+// finished, or when its last successful saveState() began, with any network
-// the live state against this to find only the fields THIS page changed since.
+// switch saved elsewhere that this page has taken since (takeStoredNetwork()).
+// saveState() diffs the live state against this to find only the fields THIS
+// page changed since.
 //
 // Deep-cloned, not a reference: callers mutate persisted objects and arrays
 // in place (state.wallets.push(...)), and a reference baseline would mutate
@@ -458,20 +461,18 @@ function mergeNetworkEndpoints(base, ours, theirs) {
 // This page's own live `state` is deliberately NOT rehydrated from a field
 // another page changed — only the record written to storage is merged.
 // showView() fires saveState() on every navigation without awaiting it,
-// which is what makes the queue above necessary in the first place, and a
+// which is why saves from one page wait for each other (see saveState()), and
-// save that is slow to come back has no way to tell whether the field it
+// a save that is slow to come back has no way to tell whether the field it
 // is about to hand back is still the current answer or has since been
 // overtaken by something this very page did in the meantime; writing it
 // into `state` regardless reintroduced exactly the clobber this function
 // exists to remove, just delayed and confined to one page instead of two
 // (caught by tests/txStatus.test.js). A page's live picture of a field it
 // does not own goes on being whatever its last loadState() saw, same as
-// before this fix; only the persisted record is guaranteed current.
+// before this fix; only the persisted record is guaranteed current. The
-async function saveStateOnce() {
+// network is the exception: the popup takes a switch another context saved
-    // A copy, so what this save compares and writes is the page's state as it
+// through `beforeWrite` (followNetworkSwitch() in src/popup/index.js).
-    // stood when the save began. A change made while it waits on storage is
+async function saveStateOnce(beforeWrite) {
-    // left for the next save, which compares against this copy.
-    const current = structuredClone(snapshotPersisted());
     const result = await storageGet("autistmask");
     // The record in storage right now is about to be merged into and written
     // back, so it is validated exactly like a load validates it. Without this,
@@ -485,6 +486,12 @@ async function saveStateOnce() {
     // come from storage in its loaded (self-healed) shape. See
     // normalizePersisted() in persistedState.js.
     const fresh = normalizePersisted(result.autistmask);
+    if (beforeWrite && beforeWrite(fresh) === false) return;
+
+    // A copy, so what this save compares and writes is the page's state as it
+    // stood once the stored record was read. A change made while it waits on
+    // the write is left for the next save, which compares against this copy.
+    const current = structuredClone(snapshotPersisted());
 
     const merged = { ...fresh };
     for (const key of PERSISTED_FIELDS) {
@@ -529,35 +536,21 @@ async function saveStateOnce() {
     rawState.hasWallet = rawState.wallets.length > 0;
 
     // What this save compared and wrote, not the page's state now: a change
-    // made during the save must still differ from the baseline, or the save
+    // made during the save must still differ from the baseline, or the next
-    // queued after it finds nothing to store
+    // save finds nothing to store
     // (https://git.eeqj.de/sneak/AutistMask/issues/448).
     baseline = current;
 }
 
-// showView() calls saveState() on every navigation without awaiting it, so
-// two saves from the SAME page can be in flight at once — e.g. a screen
-// shown, then immediately replaced before the first save's storageGet()
-// round trip has come back. Left concurrent, the first save's turn would
-// finish after the second's live-state mutation and then re-hydrate `state`
-// from what IT read, stomping the second, later change back to a stale
-// value — the same clobber this function exists to prevent, just between
-// two saves on one page instead of two pages. Queuing makes every save's
-// snapshot-diff-write-rehydrate run start to finish before the next one
-// begins, so each one only ever sees the true live state at its turn.
-let saveQueue = Promise.resolve();
-
 // Where a failed save is REPORTED, set once by the context that has a screen
 // to say it on (src/popup/index.js).
 //
 // A save that fails must not fail silently. showView() fires saveState() on
-// every navigation without awaiting it, and the queue below has to attach a
+// every navigation without awaiting it, and `await saveState()` inside an
-// rejection handler to keep advancing — so a failing save was swallowed
+// unguarded event handler is no better: either way, without this, a failure
-// entirely: no throw, no message, nothing on screen. The wallet kept running
+// would reach only the console, where the user never looks, and the wallet
-// against storage that was rejecting every write, which is the data-loss half
+// would keep running against storage that rejects every write. That is the
-// of https://git.eeqj.de/sneak/AutistMask/issues/362. The awaited callers were
+// data-loss half of https://git.eeqj.de/sneak/AutistMask/issues/362.
-// no better off: `await saveState()` inside an unguarded event handler surfaces
-// in the console and nowhere the user looks.
 //
 // This is the "tell the user" half; the other half is the floor in
 // normalizePersisted(), which stops the malformed-record cause from arising in
@@ -583,11 +576,25 @@ function reportSaveFailure(err) {
     }
 }
 
-function saveState() {
+// Each save runs start to finish holding the lock every write of the stored
-    const turn = saveQueue.then(saveStateOnce);
+// record takes (withLock() in src/shared/browserApi.js), so no write by
-    // The queue must advance even when a save rejects, or every save after
+// another page or the background lands between its read and its write and is
-    // it queues behind a promise that never settles.
+// lost (https://git.eeqj.de/sneak/AutistMask/issues/641). A page in a Firefox
-    saveQueue = turn.catch(() => {});
+// private window is the exception: Firefox gives it locks of its own (README,
+// "Stored state and its version").
+//
+// The same lock orders this page's own saves. showView() calls saveState() on
+// every navigation without awaiting it, so two saves from one page can be
+// asked for at once; they take the lock in the order they were asked, and each
+// compares the page's state, as it stands once the stored record has been read
+// and `beforeWrite` has run, against the baseline the save before it left.
+//
+// `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. When it returns false, nothing is
+// written; any other return lets the save go ahead.
+function saveState(beforeWrite) {
+    const turn = withLock("autistmask", () => saveStateOnce(beforeWrite));
     // Every failed save is reported, whether or not the caller awaited this
     // one. The returned promise still rejects, so a caller that DOES await
     // keeps its own error handling.
@@ -595,6 +602,17 @@ function saveState() {
     return turn;
 }
 
+// Give this page the network switch held by `stored`, a record a save of this
+// page has just read (followNetworkSwitch() in src/popup/index.js calls this
+// from `beforeWrite`), in `state` and in `baseline` alike, as loadState() does
+// with a whole record. The switch is then not this page's own change, even when
+// that save fails to write: a later switch back to the previous network still
+// differs from `baseline`, and is stored.
+function takeStoredNetwork(stored) {
+    copyChainSwitchFields(rawState, stored);
+    copyChainSwitchFields(baseline, structuredClone(stored));
+}
+
 // Rejects with StateUnusableError for a stored record this build cannot make
 // sense of. Nothing is assigned and `loaded` stays false in that case, so a
 // caller that ignores the rejection gets StateNotLoadedError on the first
@@ -640,6 +658,7 @@ module.exports = {
     state,
     saveState,
     onSaveFailure,
+    takeStoredNetwork,
     loadState,
     currentAddress,
     currentNetwork,

src/shared/transactions.js

@@ -20,6 +20,7 @@ const { toDecimals } = require("./transferAmount");
 // truncation without the approval screens' nonzero floor: the transaction
 // detail view is the authoritative record and already shows exact precision.
 const { truncateAmount: formatTxValue } = require("./amountDisplay");
+const { routerRelease } = require("./uniswap");
 
 // Ethereum addresses are case-insensitive: EIP-55 mixed case is a checksum
 // over the address, not part of its identity.  Every address comparison in
@@ -51,7 +52,6 @@ function parseTx(tx, addrLower, chainId) {
         }
         // Map known DEX methods to "Swap" for cleaner display
         const SWAP_METHODS = new Set([
-            "execute",
             "swap",
             "swapExactTokensForTokens",
             "swapTokensForExactTokens",
@@ -59,9 +59,16 @@ function parseTx(tx, addrLower, chainId) {
             "swapTokensForExactETH",
             "swapExactTokensForETH",
             "swapETHForExactTokens",
-            "multicall",
         ]);
-        const label = SWAP_METHODS.has(method)
+        // Multisigs, smart accounts and many other contracts also have an
+        // `execute` or `multicall` method, so either is a swap only when sent
+        // to a Universal Router on this transaction's network: the same
+        // addresses the approval screen decodes a swap for.
+        const isSwap =
+            SWAP_METHODS.has(method) ||
+            ((method === "execute" || method === "multicall") &&
+                routerRelease(to, chainId) !== null);
+        const label = isSwap
             ? "Swap"
             : method.charAt(0).toUpperCase() + method.slice(1);
         direction = "contract";

tests/addedTokenBalance.test.js

@@ -0,0 +1,273 @@
+// After "Add" on AddToken, AddressDetail lists the new token, and its line reads
+// `quantity unknown`, not 0.0000, until a balance refresh that asked the
+// explorer about the token has returned for every address, the popup closing
+// and opening again meanwhile included; so does a token added on
+// SettingsAddToken, wherever it is listed. A refresh that returns draws the
+// balances on AddressDetail or AddressToken again, so the fetched balance shows
+// without the screen being reopened
+// (https://git.eeqj.de/sneak/AutistMask/issues/516). Driven through the real
+// popup over a stored profile on Ethereum Mainnet, with "Show tracked tokens
+// with zero balance" on, as it is by default.
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+} = require("./support/popupBoot");
+
+// Tracked by nobody until a test adds it.
+const NEW_TOKEN = "0xBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB";
+
+// The explorer's row for a holding of a million NEW_TOKEN, in the shape
+// fetchTokenBalances() stores it.
+const MILLION = {
+    address: NEW_TOKEN,
+    name: "New Token",
+    symbol: "NEW",
+    decimals: 18,
+    balance: "1000000.0",
+    holders: 3,
+};
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+// The popup reopened onto AddressDetail for the one address.
+function bootOnAddress() {
+    return bootPopup(
+        unversionedValidProfile({
+            currentView: "address",
+            selectedWallet: 0,
+            selectedAddress: 0,
+        }),
+    );
+}
+
+// Holds the next balance refresh open. The returned function lets it finish
+// with the address's ETH balance at 2 and `tokenBalances` as the explorer's
+// rows for it, or with no token balances at all when given null: an explorer
+// that did not answer, which the real refreshBalances() leaves unwritten.
+function holdNextRefresh(page) {
+    const { refreshBalances } = require("../src/shared/balances");
+    let release;
+    refreshBalances.mockImplementationOnce(async (wallets) => {
+        const tokenBalances = await new Promise((resolve) => {
+            release = resolve;
+        });
+        wallets[0].addresses[0].balance = "2.0";
+        if (tokenBalances !== null) {
+            wallets[0].addresses[0].tokenBalances = tokenBalances;
+        }
+    });
+    return async (tokenBalances) => {
+        release(tokenBalances);
+        await page.settle();
+    };
+}
+
+// "+ Token", NEW_TOKEN typed in, and "Add", with the contract lookup
+// answering at once.
+async function addNewToken(page) {
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    lookupTokenInfo.mockResolvedValueOnce({
+        symbol: "NEW",
+        decimals: 18,
+        name: "New Token",
+    });
+    await page.click("btn-add-token");
+    page.node("add-token-address").value = NEW_TOKEN;
+    await page.click("btn-add-token-confirm");
+}
+
+// NEW_TOKEN's row in the balance list in element `id`, AddressDetail's unless
+// another is named, as markup.
+function newTokenRow(page, id = "address-balances") {
+    return page
+        .node(id)
+        .innerHTML.split("<div ")
+        .find((row) =>
+            row.includes('data-token="' + NEW_TOKEN.toLowerCase() + '"'),
+        );
+}
+
+// AddressDetail for the one address opened from Home, as its `[info]` button
+// does.
+async function openAddress(page) {
+    const { state } = require("../src/shared/state");
+    state.selectedWallet = 0;
+    state.selectedAddress = 0;
+    require("../src/popup/views/helpers").pushCurrentView();
+    require("../src/popup/views/addressDetail").show();
+    await page.settle();
+}
+
+// AddressToken for `token` opened from AddressDetail, as tapping the token's
+// row there does.
+async function openToken(page, token) {
+    const { state } = require("../src/shared/state");
+    state.selectedToken = token;
+    require("../src/popup/views/helpers").pushCurrentView();
+    require("../src/popup/views/addressToken").show();
+    await page.settle();
+}
+
+test("until the refresh Add started returns, the new token's line reads quantity unknown", async () => {
+    const page = await bootOnAddress();
+    expect(page.pageErrors).toEqual([]);
+    const finish = holdNextRefresh(page);
+
+    await addNewToken(page);
+
+    expect(page.visibleViews()).toEqual(["address"]);
+    const row = newTokenRow(page);
+    expect(row).toContain("quantity unknown");
+    expect(row).not.toContain("0.0000");
+    await finish([MILLION]);
+});
+
+test("once that refresh returns, AddressDetail shows the fetched balance without being reopened", async () => {
+    const page = await bootOnAddress();
+    const finish = holdNextRefresh(page);
+    await addNewToken(page);
+    // Stands for the transactions on the screen, which only show() replaces.
+    page.node("tx-list").innerHTML = "transactions on the screen";
+
+    await finish([MILLION]);
+
+    expect(page.visibleViews()).toEqual(["address"]);
+    expect(newTokenRow(page)).toContain("1000000.0000");
+    // Only the balances are drawn again, not the transaction list.
+    expect(page.node("tx-list").innerHTML).toBe("transactions on the screen");
+});
+
+test("a refresh already running when the token is added does not count as fetching it", async () => {
+    const page = await bootOnAddress();
+    const finishRunning = holdNextRefresh(page);
+    const ticking = page.tick();
+    await page.settle();
+
+    await addNewToken(page);
+    await finishRunning([]);
+    await ticking;
+
+    expect(newTokenRow(page)).toContain("quantity unknown");
+
+    // The next one asks the explorer about the token, which lists no holding
+    // of it: a fetched zero.
+    const finishNext = holdNextRefresh(page);
+    const next = page.tick();
+    await page.settle();
+    await finishNext([]);
+    await next;
+
+    expect(newTokenRow(page)).toContain("0.0000");
+});
+
+test("closed and opened again before any refresh has fetched it, the new token's line still reads quantity unknown", async () => {
+    const closed = await bootOnAddress();
+    holdNextRefresh(closed);
+    await addNewToken(closed);
+    cleanupPopup();
+
+    // The refresh this boot starts gets no token balances back: the boot's
+    // stub of refreshBalances() writes none.
+    const page = await bootPopup(undefined, { storage: closed.storage });
+    expect(page.visibleViews()).toEqual(["address"]);
+    const row = newTokenRow(page);
+    expect(row).toContain("quantity unknown");
+    expect(row).not.toContain("0.0000");
+
+    const finish = holdNextRefresh(page);
+    const ticking = page.tick();
+    await page.settle();
+    await finish([MILLION]);
+    await ticking;
+
+    expect(newTokenRow(page)).toContain("1000000.0000");
+});
+
+test("a refresh in which the explorer did not answer leaves the new token's line quantity unknown", async () => {
+    const page = await bootOnAddress();
+    const finish = holdNextRefresh(page);
+    await addNewToken(page);
+
+    await finish(null);
+
+    // Drawn again: the ETH balance it fetched is shown.
+    expect(page.node("address-balances").innerHTML).toContain("2.0000");
+    expect(newTokenRow(page)).toContain("quantity unknown");
+});
+
+test("AddressToken for the new token reads quantity unknown until the refresh returns, then the fetched balance", async () => {
+    const page = await bootOnAddress();
+    const finish = holdNextRefresh(page);
+    await addNewToken(page);
+
+    await openToken(page, NEW_TOKEN.toLowerCase());
+
+    expect(page.visibleViews()).toEqual(["address-token"]);
+    const before = page.node("address-token-balance").innerHTML;
+    expect(before).toContain("quantity unknown");
+    expect(before).not.toContain("0.0000");
+
+    await finish([MILLION]);
+
+    expect(page.node("address-token-balance").innerHTML).toContain(
+        "1000000.0000",
+    );
+});
+
+test("a token added by contract address on SettingsAddToken reads quantity unknown until the refresh returns", async () => {
+    const page = await bootPopup(unversionedValidProfile());
+    expect(page.visibleViews()).toEqual(["main"]);
+    const finish = holdNextRefresh(page);
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    lookupTokenInfo.mockResolvedValueOnce({
+        symbol: "NEW",
+        decimals: 18,
+        name: "New Token",
+    });
+
+    await page.click("btn-settings");
+    await page.click("btn-settings-add-token");
+    page.node("settings-addtoken-address").value = NEW_TOKEN;
+    await page.click("btn-settings-addtoken-manual");
+    await page.click("btn-settings-addtoken-back");
+    await page.click("btn-settings-back");
+    expect(page.visibleViews()).toEqual(["main"]);
+    const onHome = newTokenRow(page, "wallet-list");
+    expect(onHome).toContain("quantity unknown");
+    expect(onHome).not.toContain("0.0000");
+
+    await openAddress(page);
+    const onAddress = newTokenRow(page);
+    expect(onAddress).toContain("quantity unknown");
+    expect(onAddress).not.toContain("0.0000");
+
+    await finish([MILLION]);
+
+    expect(newTokenRow(page)).toContain("1000000.0000");
+});
+
+test("a refresh that returns while AddressToken is up draws its balance again", async () => {
+    const page = await bootPopup(
+        unversionedValidProfile({
+            currentView: "address-token",
+            viewStack: ["main", "address"],
+            selectedWallet: 0,
+            selectedAddress: 0,
+            selectedToken: "ETH",
+        }),
+    );
+    expect(page.visibleViews()).toEqual(["address-token"]);
+    expect(page.node("address-token-balance").innerHTML).toContain("1.5000");
+    const finish = holdNextRefresh(page);
+    const ticking = page.tick();
+    await page.settle();
+
+    await finish(null);
+    await ticking;
+
+    expect(page.node("address-token-balance").innerHTML).toContain("2.0000");
+});

tests/approvalTokenNetwork.test.js

@@ -1,11 +1,16 @@
 // The approval screen for a site's Sepolia token transfer while Ethereum
-// Mainnet is active (https://git.eeqj.de/sneak/AutistMask/issues/629).
+// Mainnet is active.
 //
 // The screen named the token, and scaled its amount, from the active network's
 // tracked tokens and balances, so a token the wallet tracks on Sepolia read as
 // an unknown token with its amount in base units, and the screens after it
-// labelled the amount `?`. It now uses what the wallet knows of the tokens on
+// labelled the amount `?` (https://git.eeqj.de/sneak/AutistMask/issues/629).
-// the network the transaction is for.
+// It now uses what the wallet knows of the tokens on the network the
+// transaction is for.
+//
+// Its address links opened the active network's explorer
+// (https://git.eeqj.de/sneak/AutistMask/issues/631). They now open the
+// explorer of the network the transaction is for.
 //
 // Driven through the real approval screen, password and Confirm included,
 // against a minimal DOM stub in the shape tests/swapStatusAmount.test.js uses.
@@ -107,10 +112,13 @@ function decodedLine(label) {
 }
 
 // Open the approval screen, with Ethereum Mainnet active and FROM holding
-// `tokenBalances` there, for the site's Sepolia transaction sending
+// `tokenBalances` there, for the site's transaction sending TRANSFER_DATA to
-// TRANSFER_DATA to the token. Confirm answers the signed transaction with a
+// the token, on Sepolia unless `chainId` names another chain. Confirm answers
-// failure, which leads to the error screen.
+// the signed transaction with a failure, which leads to the error screen.
-async function showSepoliaTransfer(tokenBalances = []) {
+async function showTokenTransfer(
+    tokenBalances = [],
+    chainId = NETWORKS.sepolia.chainId,
+) {
     globalThis.document = makeDocument();
     globalThis.window = { location: { search: "" }, close: () => {} };
     globalThis.chrome.runtime = {
@@ -131,7 +139,7 @@ async function showSepoliaTransfer(tokenBalances = []) {
                 approvedTx: {
                     type: 2,
                     from: FROM,
-                    chainId: NETWORKS.sepolia.chainId,
+                    chainId,
                     nonce: "0x7",
                     gasLimit: "0x30d40",
                     maxPriorityFeePerGas: "0x3b9aca00",
@@ -183,7 +191,7 @@ describe("a token tracked on Sepolia only", () => {
     });
 
     test("is named on the Contract line and the decoded Token line, with its amount at its scale", async () => {
-        await showSepoliaTransfer();
+        await showTokenTransfer();
         expect(node("approve-tx-to").innerHTML).toContain(
             '<div class="font-bold mb-1">TDOL</div>',
         );
@@ -196,7 +204,7 @@ describe("a token tracked on Sepolia only", () => {
     });
 
     test("labels the amount on the error screen that follows", async () => {
-        await showSepoliaTransfer();
+        await showTokenTransfer();
         await confirm();
         expect(state.currentView).toBe("error-tx");
         expect(node("error-tx-summary").textContent).toBe("1234.5000 TDOL");
@@ -207,7 +215,7 @@ describe("a token tracked on Sepolia only", () => {
 // tracks and holds there names nothing on Sepolia.
 test("a token tracked and held on mainnet only is not named, and its amount is in base units", async () => {
     state.trackedTokens = [{ address: TOKEN, symbol: "MDOL", decimals: 18 }];
-    await showSepoliaTransfer([
+    await showTokenTransfer([
         { address: TOKEN, symbol: "MDOL", decimals: 18, balance: "1.0" },
     ]);
     expect(node("approve-tx-to").innerHTML).not.toContain("MDOL");
@@ -218,3 +226,45 @@ test("a token tracked and held on mainnet only is not named, and its amount is i
         '<div class="font-bold">1234500000 base units (decimals unknown)</div>',
     );
 });
+
+// The From and Contract lines, and the decoded Token and Recipient lines.
+test("every address links to the Sepolia explorer", async () => {
+    await showTokenTransfer();
+    const sepolia = NETWORKS.sepolia.explorerUrl;
+    expect(node("approve-tx-from").innerHTML).toContain(
+        `href="${sepolia}/address/${FROM}"`,
+    );
+    expect(node("approve-tx-to").innerHTML).toContain(
+        `href="${sepolia}/address/${TOKEN}"`,
+    );
+    expect(decodedLine("Token")).toContain(
+        `href="${sepolia}/address/${TOKEN}"`,
+    );
+    expect(decodedLine("Recipient")).toContain(
+        `href="${sepolia}/address/${RECIPIENT}"`,
+    );
+    for (const id of [
+        "approve-tx-from",
+        "approve-tx-to",
+        "approve-tx-decoded-details",
+    ]) {
+        expect(node(id).innerHTML).not.toContain(NETWORKS.mainnet.explorerUrl);
+    }
+});
+
+// Chain id 1337 names no network here, so it has no explorer to link to.
+test("a transaction on a chain id that names no network is shown with no address links", async () => {
+    await showTokenTransfer([], "0x539");
+    expect(state.currentView).toBe("approve-tx");
+    expect(node("approve-tx-network").textContent).toBe(
+        "Unknown network (chain id 1337)",
+    );
+    expect(node("approve-tx-from").innerHTML).toContain(FROM);
+    for (const id of [
+        "approve-tx-from",
+        "approve-tx-to",
+        "approve-tx-decoded-details",
+    ]) {
+        expect(node(id).innerHTML).not.toContain("href=");
+    }
+});

tests/approvalValueUsd.test.js

@@ -0,0 +1,192 @@
+// The USD value on the approval screen's Value and Network fee lines, for a
+// site's ETH send.
+//
+// It was worked out from the four-decimal figure the line shows, at the price
+// on the active network, so the same value read a few cents different here than
+// on the confirmation screen, which prices the exact amount at the price on the
+// transaction's own network, and a transaction on another network than the
+// active one was priced at the active one's rate, its fee too
+// (https://git.eeqj.de/sneak/AutistMask/issues/614).
+//
+// Driven through the real approval screen, against a minimal DOM stub in the
+// shape tests/approvalTokenNetwork.test.js uses.
+
+globalThis.chrome = {
+    storage: { local: { get: async () => ({}), set: async () => {} } },
+};
+
+const { state } = require("../src/shared/state");
+const { NETWORKS } = require("../src/shared/networks");
+const { prices, clearPrices } = require("../src/shared/prices");
+const approval = require("../src/popup/views/approval");
+
+const FROM = "0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266";
+const RECIPIENT = "0x711e691962E5c054b78071C789A0C8CE657377aD";
+
+function makeElement(id) {
+    const classes = new Set();
+    const el = {
+        id,
+        textContent: "",
+        value: "",
+        innerHTML: "",
+        disabled: false,
+        style: {},
+        dataset: {},
+        listeners: {},
+        classList: {
+            add: (...names) => names.forEach((n) => classes.add(n)),
+            remove: (...names) => names.forEach((n) => classes.delete(n)),
+            contains: (n) => classes.has(n),
+            toggle: (n, force) => {
+                const on = force === undefined ? !classes.has(n) : force;
+                if (on) classes.add(n);
+                else classes.delete(n);
+                return on;
+            },
+        },
+        addEventListener: (name, fn) => {
+            el.listeners[name] = el.listeners[name] || [];
+            el.listeners[name].push(fn);
+        },
+        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"),
+        body: { prepend: () => {} },
+    };
+}
+
+function node(id) {
+    return globalThis.document.getElementById(id);
+}
+
+// Open the approval screen, with the network `networkId` active, for the
+// site's transaction sending 1.23414 ETH to RECIPIENT on the chain `chainId`.
+async function showEthSend(chainId, networkId) {
+    globalThis.document = makeDocument();
+    globalThis.window = { location: { search: "" }, close: () => {} };
+    globalThis.chrome.runtime = {
+        connect: () => ({ postMessage: () => {} }),
+        sendMessage: (msg, reply) => {
+            if (!reply) return;
+            reply({
+                type: "tx",
+                origin: "https://dapp.example",
+                isPhishingDomain: false,
+                approvedFrom: FROM,
+                approvedTx: {
+                    type: 2,
+                    from: FROM,
+                    chainId,
+                    nonce: "0x7",
+                    gasLimit: "0x5208",
+                    maxPriorityFeePerGas: "0x3b9aca00",
+                    maxFeePerGas: "0x77359400",
+                    to: RECIPIENT,
+                    value: "1234140000000000000",
+                    data: "0x",
+                    accessList: [],
+                },
+            });
+        },
+    };
+    state.networkId = networkId;
+    state.activeAddress = FROM;
+    state.wallets = [
+        {
+            type: "hd",
+            name: "Wallet 1",
+            xpub: "xpub-wallet-1",
+            encryptedSecret: "encrypted-secret-1",
+            nextIndex: 1,
+            addresses: [{ address: FROM, index: 0, balance: "0" }],
+        },
+    ];
+    state.trackedTokens = [];
+    state.networkTrackedTokens = {};
+    state.currentView = null;
+    approval.init({});
+    await approval.show(1);
+}
+
+beforeEach(() => {
+    prices.ETH = 2000;
+});
+
+afterEach(() => {
+    clearPrices();
+});
+
+// 1.23414 ETH reads 1.2341 ETH. At $2,000 the exact value is $2,468.28, the
+// figure the confirmation screen shows for it; the shown figure would be
+// $2,468.20.
+test.each([
+    [
+        "a mainnet transaction is priced from its exact value",
+        NETWORKS.mainnet.chainId,
+        "mainnet",
+        "1.2341 ETH ($2,468.28)",
+    ],
+    [
+        "a mainnet transaction shown with Sepolia active is priced at the mainnet price",
+        NETWORKS.mainnet.chainId,
+        "sepolia",
+        "1.2341 ETH ($2,468.28)",
+    ],
+    [
+        "a Sepolia transaction shown with mainnet active has no USD value",
+        NETWORKS.sepolia.chainId,
+        "mainnet",
+        "1.2341 SepoliaETH",
+    ],
+    // Chain id 1337 names no network here, so nothing knows its price.
+    [
+        "a transaction on a chain id that names no network has no USD value",
+        "0x539",
+        "mainnet",
+        "1.2341 ETH",
+    ],
+])("%s", async (_label, chainId, networkId, expected) => {
+    await showEthSend(chainId, networkId);
+    expect(state.currentView).toBe("approve-tx");
+    expect(node("approve-tx-value").textContent).toBe(expected);
+});
+
+// The Network fee line is priced on the transaction's network too. 21000 gas at
+// up to 2 gwei is 0.000042 ETH, $0.08 at $2,000.
+test.each([
+    [
+        "the fee of a mainnet transaction shown with Sepolia active is priced at the mainnet price",
+        NETWORKS.mainnet.chainId,
+        "sepolia",
+        "0.00004 ETH ($0.08)",
+    ],
+    [
+        "the fee of a Sepolia transaction shown with mainnet active has no USD value",
+        NETWORKS.sepolia.chainId,
+        "mainnet",
+        "0.00004 SepoliaETH",
+    ],
+])("%s", async (_label, chainId, networkId, expected) => {
+    await showEthSend(chainId, networkId);
+    expect(state.currentView).toBe("approve-tx");
+    expect(node("approve-tx-fee").textContent).toBe(expected);
+});

tests/backgroundStateIsolation.test.js

@@ -19,7 +19,10 @@
 //     that followed persisted the pre-refresh values — while still stamping
 //     lastBalanceRefresh, suppressing the redo.
 //
-// Both use the real persistence path over a cloning storage stub. Nothing here
+// A network switch landing inside a balance refresh's round trip is covered at
+// the end (https://git.eeqj.de/sneak/AutistMask/issues/577).
+//
+// All use the real persistence path over a cloning storage stub. Nothing here
 // asserts the absence of a loadState() call; each asserts the OUTCOME, so it
 // holds against any implementation that gets the outcome right.
 
@@ -395,3 +398,48 @@ describe("a balance refresh under another handler's state read", () => {
         expect(after.wallets[0].addresses[0].balance).toBe(REFRESHED_BALANCE);
     });
 });
+
+describe("a balance refresh under a network switch", () => {
+    // https://git.eeqj.de/sneak/AutistMask/issues/577. The switch clears every
+    // address's balances, and a refresh that started on the previous network
+    // must not write that network's back over them when it returns. The same
+    // refresh in the popup is in tests/balanceRefreshNetworkSwitch.test.js.
+    test("a refresh that returns after a switch writes nothing, and the next one runs on the new network", async () => {
+        const roundTrip = deferred();
+        const reachedNetwork = deferred();
+        const ranOn = [];
+
+        const bg = loadWorker("sepolia", {
+            refreshBalances: async (wallets, rpcUrl, explorer, tokens, id) => {
+                ranOn.push(id);
+                reachedNetwork.resolve();
+                await roundTrip.promise;
+                wallets[0].addresses[0].balance = REFRESHED_BALANCE;
+            },
+        });
+
+        const refresh = bg.fireBalanceAlarm();
+        await reachedNetwork.promise;
+
+        // The user switches to Ethereum Mainnet in Settings while the round
+        // trip is out.
+        const during = bg.persisted();
+        applyChainSwitchFields(during, MAINNET.id);
+        global.chrome.storage.write("autistmask", during);
+
+        roundTrip.resolve();
+        await refresh;
+
+        const after = bg.persisted();
+        expect(after.networkId).toBe("mainnet");
+        expect(after.wallets[0].addresses[0].balance).toBe("0");
+        expect(after.lastBalanceRefresh).toBe(0);
+
+        await bg.fireBalanceAlarm();
+
+        expect(ranOn).toEqual(["sepolia", "mainnet"]);
+        expect(bg.persisted().wallets[0].addresses[0].balance).toBe(
+            REFRESHED_BALANCE,
+        );
+    });
+});

tests/balanceRefreshNetworkSwitch.test.js

@@ -0,0 +1,161 @@
+// A balance refresh the popup started on one network, and that returns after
+// the network was switched to another, writes nothing: the switch cleared every
+// address's balances, and the previous network's must not come back over them
+// (https://git.eeqj.de/sneak/AutistMask/issues/577). The switch is made either
+// by the user in this popup's Settings, or by the background after the user
+// approved a site's request, which changes only the stored record. Driven
+// through the real popup over a stored profile on Ethereum Mainnet. The same
+// refresh in the background is in tests/backgroundStateIsolation.test.js.
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    TOKEN_ADDRESS,
+} = require("./support/popupBoot");
+const { applyChainSwitchFields } = require("../src/shared/chainSwitchFields");
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+// Starts the ten-second refresh and holds it open. The balance stand-in writes
+// Ethereum Mainnet's balances in place, on the records handed in, as the real
+// refreshBalances() does, once the returned function is called. Resolves with
+// that function and the refresh still running.
+async function holdRefresh(page) {
+    const { refreshBalances } = require("../src/shared/balances");
+    let answer;
+    refreshBalances.mockImplementationOnce(async (wallets) => {
+        await new Promise((resolve) => {
+            answer = resolve;
+        });
+        wallets[0].addresses[0].balance = "7.0";
+        wallets[0].addresses[0].tokenBalances = [
+            {
+                address: TOKEN_ADDRESS,
+                name: "Test Token",
+                symbol: "TST",
+                decimals: 18,
+                balance: "5.0",
+                holders: null,
+            },
+        ];
+    });
+    const ticking = page.tick();
+    await page.settle();
+    return {
+        finish: async () => {
+            answer();
+            await ticking;
+        },
+    };
+}
+
+// Picks `networkId` in the Settings network selector, as the user does.
+async function chooseNetwork(page, networkId) {
+    const select = page.node("settings-network");
+    select.value = networkId;
+    for (const fn of select.listeners.change) await fn();
+    await page.settle();
+}
+
+// The stored record holds none of Ethereum Mainnet's balances, and no refresh
+// recorded as done.
+function expectNothingStored(page) {
+    const stored = page.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.wallets[0].addresses[0].balance).toBe("0");
+    expect(stored.wallets[0].addresses[0].tokenBalances).toEqual([]);
+    expect(stored.lastBalanceRefresh).toBe(0);
+}
+
+test("a refresh that returns after a switch in Settings writes nothing, and the next one runs on the new network", async () => {
+    const page = await bootPopup(unversionedValidProfile());
+    expect(page.pageErrors).toEqual([]);
+    const { refreshBalances } = require("../src/shared/balances");
+    const { state } = require("../src/shared/state");
+
+    const refresh = await holdRefresh(page);
+    await page.click("btn-settings");
+    await chooseNetwork(page, "sepolia");
+    await refresh.finish();
+
+    expect(state.wallets[0].addresses[0].balance).toBe("0");
+    expect(state.wallets[0].addresses[0].tokenBalances).toEqual([]);
+    expectNothingStored(page);
+
+    await page.click("btn-settings-back");
+    expect(page.visibleViews()).toEqual(["main"]);
+    expect(page.text("total-value")).toBe("0.0000 SepoliaETH");
+
+    await page.tick();
+
+    expect(refreshBalances.mock.lastCall[4]).toBe("sepolia");
+    expect(page.storage.read("autistmask").lastBalanceRefresh).toBeGreaterThan(
+        0,
+    );
+});
+
+// The switch is made only once the refresh's save, holding the lock, has
+// written Ethereum Mainnet's balances, and the switch then clears them.
+test("a refresh whose save is reading the stored record when the user switches in Settings leaves none of its balances stored", async () => {
+    const page = await bootPopup(unversionedValidProfile());
+    expect(page.pageErrors).toEqual([]);
+    const { state } = require("../src/shared/state");
+
+    const refresh = await holdRefresh(page);
+    await page.click("btn-settings");
+
+    // The next read of the stored record, the refresh's save's, is held.
+    const get = page.storage.local.get;
+    const read = get.getMockImplementation();
+    let releaseRead;
+    get.mockImplementationOnce(async (key) => {
+        await new Promise((resolve) => {
+            releaseRead = resolve;
+        });
+        return read(key);
+    });
+    const finishing = refresh.finish();
+    await page.settle();
+
+    // The user picks Sepolia meanwhile; the switch's own save waits for the
+    // refresh's save to let the lock go.
+    const select = page.node("settings-network");
+    select.value = "sepolia";
+    const switching = Promise.all(select.listeners.change.map((fn) => fn()));
+    await page.settle();
+
+    releaseRead();
+    await finishing;
+    await switching;
+    await page.settle();
+
+    expect(state.networkId).toBe("sepolia");
+    expect(state.wallets[0].addresses[0].balance).toBe("0");
+    expect(state.wallets[0].addresses[0].tokenBalances).toEqual([]);
+    expectNothingStored(page);
+});
+
+test("a refresh that returns after the background switched the network writes nothing", async () => {
+    const page = await bootPopup(unversionedValidProfile());
+    expect(page.pageErrors).toEqual([]);
+    const { saveState } = require("../src/shared/state");
+
+    const refresh = await holdRefresh(page);
+    // The background writes the switch to Sepolia, as its updateState() does
+    // once the user approves a site's request. This page is not told of it
+    // yet.
+    const record = page.storage.read("autistmask");
+    applyChainSwitchFields(record, "sepolia");
+    page.storage.write("autistmask", record);
+    await refresh.finish();
+
+    expectNothingStored(page);
+
+    // Nor does a later save by this page, such as every navigation makes.
+    await saveState();
+
+    expectNothingStored(page);
+});

tests/chainSwitchGate.test.js

@@ -446,7 +446,10 @@ describe("switching the network in Settings tells every open tab", () => {
         global.chrome.runtime.sendMessage = (msg) => {
             bg.send(msg, POPUP);
         };
-        await require("../src/shared/state").loadState();
+        const { state, loadState } = require("../src/shared/state");
+        await loadState();
+        // Set by showView(), which is mocked above.
+        state.currentView = "settings";
         require("../src/popup/views/settings").init({
             pageClosed: new AbortController().signal,
         });

tests/confirmTxAmount.test.js

@@ -158,7 +158,7 @@ global.document = {
     body: { prepend() {}, appendChild() {} },
     addEventListener() {},
 };
-global.navigator = { clipboard: { writeText() {} } };
+global.navigator.clipboard = { writeText() {} };
 
 const {
     Interface,

tests/confirmTxNetworkSwitch.test.js

@@ -189,7 +189,7 @@ global.document = {
     body: { prepend() {}, appendChild() {} },
     addEventListener() {},
 };
-global.navigator = { clipboard: { writeText() {} } };
+global.navigator.clipboard = { writeText() {} };
 
 const {
     BaseWallet,

tests/dustThreshold.test.js

@@ -101,7 +101,7 @@ describe("the flash line the message is shown in", () => {
     //
     // The line cuts a message too long for it with an ellipsis (see
     // showFlash() in src/popup/views/helpers.js). The assertions that
-    // measure that, in a real browser at the documented 360x600 popup, are
+    // measure that, in a real browser at the documented 396x600 popup, are
     // "a rejected dust threshold shifts no layout (#233)" and "an over-long
     // flash message keeps to one line (#252)" in tests/e2e/run.js, run by
     // make test-e2e. They are not in make check because REPO_POLICIES.md

tests/e2e/firefox/run.js

@@ -867,6 +867,14 @@ step(
             "the page was not told of the approved switch: " +
                 JSON.stringify(events),
         );
+        // The popup, open all along, shows the new network
+        // (https://git.eeqj.de/sneak/AutistMask/issues/650).
+        await d.switchToWindow(env.popupWindow);
+        await d.waitFor(
+            "the open popup to show the testnet banner",
+            `const banner = document.getElementById("debug-banner");
+             return banner !== null && banner.textContent === "[TESTNET]";`,
+        );
 
         await openNetworkPrompt(env, "switch-restore", sepolia, mainnet);
         await d.click("#btn-approve-network");
@@ -881,6 +889,10 @@ step(
             isDeepStrictEqual(await storedNetwork(env), before),
             "switching back did not restore the mainnet network and endpoints",
         );
+        await d.waitFor(
+            "the open popup to drop the testnet banner",
+            `return document.getElementById("debug-banner") === null;`,
+        );
         await d.switchToWindow(env.dappWindow);
     },
 );

tests/e2e/run.js

@@ -60,6 +60,14 @@ const TEST_TIMEOUT_MS = 120000;
 // trailing drain in main().
 const TRAILING_WATCH_MS = 1500;
 
+// The popup's size, as README gives it: `body` in src/popup/styles/main.css
+// is 396px wide, and src/background/index.js opens an approval window at
+// the same 396x600. Pages in this context otherwise get Playwright's
+// 1280x720 default, where the page never scrolls sideways and a button
+// below the popup's fold is still on screen, so a layout measured there
+// passes whatever the page does.
+const POPUP_VIEWPORT = { width: 396, height: 600 };
+
 const tests = [];
 
 function test(name, fn) {
@@ -359,11 +367,14 @@ async function leaveTransactionDetail(page) {
     await openAddressDetail(page);
 }
 
-// Back out to Home from wherever the previous test finished.
+// Back out to Home from wherever the previous test finished, and wait for the
+// save that navigation makes, so a test reading the stored stack next reads
+// the one Home left.
 async function goHome(page) {
     await leaveTransactionDetail(page);
     await page.click("#btn-address-back");
     await visible(page, "#view-main");
+    await waitForPersisted(page, "currentView", "main", "back on Home");
 }
 
 // One field of the popup's state as it was actually persisted, read out of
@@ -640,7 +651,8 @@ test("a token added by its contract address is listed on the address screen (#15
     await visible(env.page, "#view-address");
 
     // No wait: the confirm renders the balance list before it shows the
-    // screen, and nothing renders the list again while the screen is up.
+    // screen. The refresh it starts draws the list again, with the row still
+    // in it.
     const row = env.page.locator(
         '#address-balances [data-token="' + STUB_TOKEN.address + '"]',
         { hasText: STUB_TOKEN.symbol },
@@ -1885,12 +1897,6 @@ test("a network switch in Settings shows and removes the testnet banner at once
 
 // ------------------------------------------------ dust threshold (#233)
 
-// The popup size README documents the UI as designed for. Pages in this
-// context otherwise get Playwright's 1280x720 default, at which the flash
-// line has room for any plausible message and never wraps — measuring
-// there would pass for every string and prove nothing.
-const POPUP_VIEWPORT = { width: 360, height: 600 };
-
 // Everything below the flash line that must not move when it fills, plus
 // the height of the line itself. Runs in the page.
 //
@@ -2139,7 +2145,7 @@ test("a password error moves nothing on any screen (#297)", async (env) => {
 
 // ------------------------------------------ add wallet Import button (#493)
 
-// At 360x600 the add wallet screen's Import button already starts near the
+// At 396x600 the add wallet screen's Import button already starts near the
 // bottom of the popup, so its password error line sits beside the button
 // rather than above it. Measures the button and the line empty and again
 // filled with the longest error addWallet.js puts there. Runs in the page.
@@ -3431,10 +3437,14 @@ test("six failed receipt lookups in a row end on the unreachable-network message
 // timeout ("<iframe id=\"pwn\"> intercepts pointer events") rather than as
 // anything that names the defect.
 
-// Verbatim from the issue's reproduction.
+// The issue's reproduction, with the frame sized to the popup.
 const HOSTILE_SYMBOL =
     '<iframe id="pwn" src="https://dapp.e2e.test/" ' +
-    'style="position:fixed;left:0;top:0;width:360px;height:600px;z-index:99999"></iframe>';
+    'style="position:fixed;left:0;top:0;width:' +
+    POPUP_VIEWPORT.width +
+    "px;height:" +
+    POPUP_VIEWPORT.height +
+    'px;z-index:99999"></iframe>';
 
 // What a correctly escaped and capped render of it reads as: the first
 // MAX_SYMBOL_LENGTH-1 characters and an ellipsis. Spelled out rather than
@@ -4856,6 +4866,12 @@ test("a site's network switch changes nothing until the user approves it (#408)"
         "the page was not told of the approved switch: " +
             JSON.stringify(events),
     );
+    // The popup, open all along, shows the new network
+    // (https://git.eeqj.de/sneak/AutistMask/issues/650).
+    await env.page.waitForFunction(() => {
+        const banner = document.getElementById("debug-banner");
+        return banner !== null && banner.textContent === "[TESTNET]";
+    });
 
     const restored = await openNetworkPrompt(
         env,
@@ -4877,6 +4893,9 @@ test("a site's network switch changes nothing until the user approves it (#408)"
         isDeepStrictEqual(await storedNetwork(env.page), before),
         "switching back did not restore the mainnet network and endpoints",
     );
+    await env.page.waitForFunction(
+        () => document.getElementById("debug-banner") === null,
+    );
 });
 
 // Switching the network in Settings tells the page too, as an approved site
@@ -5026,8 +5045,20 @@ function addressRowReport(page) {
     });
 }
 
+// Measured at the popup's 396x600 (POPUP_VIEWPORT). Every page in this
+// context, approval windows included, is otherwise 1280x720 whatever size
+// the extension asks for, and a page that wide never scrolls sideways. The
+// page is then put back to the size it had, so the size a later step runs at
+// does not depend on whether this one ran.
 async function assertAddressesFit(page, where) {
-    const report = await addressRowReport(page);
+    const sizeBefore = page.viewportSize();
+    await page.setViewportSize(POPUP_VIEWPORT);
+    let report;
+    try {
+        report = await addressRowReport(page);
+    } finally {
+        await page.setViewportSize(sizeBefore);
+    }
     assert(
         report.rows.length > 0,
         where + ": no address rows were rendered, so nothing was measured",

tests/flashLine.test.js

@@ -88,6 +88,7 @@ describe.each([
             showFlash: (msg) => flashes.push(msg),
             escapeHtml: (s) => s,
             goBack: () => {},
+            trackToken: () => {},
         }));
 
         require("../src/popup/views/" + view).init({

tests/nativeCurrency.test.js

@@ -151,7 +151,7 @@ global.document = {
     body: { prepend() {}, appendChild() {} },
     addEventListener() {},
 };
-global.navigator = { clipboard: { writeText() {} } };
+global.navigator.clipboard = { writeText() {} };
 
 const { state } = require("../src/shared/state");
 const { NETWORKS } = require("../src/shared/networks");

tests/persistedEntryFloors.test.js

@@ -364,7 +364,7 @@ describe("a save that fails", () => {
         return storage;
     }
 
-    test("is reported, not swallowed by the save queue", async () => {
+    test("is reported when the caller does not await it", async () => {
         const storage = failingStorage(unversionedValidProfile());
         const { state, loadState, saveState, onSaveFailure } =
             loadStateModule(storage);

tests/persistedFieldContract.test.js

@@ -248,6 +248,13 @@ const CONTRACT = [
         floorOnly: [[42], [null], [{}], [[TOKEN_ADDRESS]]],
         holds: (v) => everyEntry(v, isText),
     },
+    {
+        field: "tokensNotFetched",
+        kind: KIND.ENTRIES,
+        hostile: [42, "notalist", { a: 1 }],
+        floorOnly: [[42], [null], [{}], [[TOKEN_ADDRESS]]],
+        holds: (v) => everyEntry(v, isText),
+    },
     {
         field: "viewStack",
         kind: KIND.ENTRIES,

tests/popupFollowsNetworkSwitch.test.js

@@ -0,0 +1,300 @@
+// An open popup follows a network switch the background saves once the user
+// approves a site's request: it takes the new network from the stored record
+// and draws the screen it is on for it, as a switch in Settings does
+// (https://git.eeqj.de/sneak/AutistMask/issues/650). Driven through the real
+// popup over a stored profile on Ethereum Mainnet. The background's write is
+// the storage stub's set, which the stub reports to the page as the browser
+// does.
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    TOKEN_ADDRESS,
+} = require("./support/popupBoot");
+const { makeStorageStub } = require("./support/storageStub");
+const {
+    applyChainSwitchFields,
+    copyChainSwitchFields,
+} = require("../src/shared/chainSwitchFields");
+const { NETWORKS } = require("../src/shared/networks");
+const { STATE_SCHEMA_VERSION } = require("../src/shared/stateSchema");
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+const SEPOLIA_TOKEN = {
+    address: TOKEN_ADDRESS,
+    symbol: "TST",
+    decimals: 18,
+    name: "Test Token",
+};
+const MAINNET_TOKEN = {
+    address: "0x6B175474E89094C44Da98b954EedeAC495271d0F",
+    symbol: "DAI",
+    decimals: 18,
+    name: "Dai Stablecoin",
+};
+
+// A profile on Ethereum Mainnet that reopens the popup onto AddressDetail,
+// with DAI tracked there and TST tracked on Sepolia.
+function profileOnAddress() {
+    return unversionedValidProfile({
+        currentView: "address",
+        viewStack: ["main"],
+        selectedWallet: 0,
+        selectedAddress: 0,
+        trackedTokens: [MAINNET_TOKEN],
+        networkTrackedTokens: { sepolia: [SEPOLIA_TOKEN] },
+    });
+}
+
+// The popup reopened onto it.
+function bootOnAddress() {
+    return bootPopup(profileOnAddress());
+}
+
+// The background saves a switch to `networkId`, as its updateState() does
+// once the user approves a site's request.
+async function backgroundSwitch(page, networkId) {
+    const record = page.storage.read("autistmask");
+    applyChainSwitchFields(record, networkId);
+    await page.storage.local.set({ autistmask: record });
+    await page.settle();
+    await page.settle();
+}
+
+test("the popup open on AddressDetail shows the new network and its balances", async () => {
+    const page = await bootOnAddress();
+    expect(page.pageErrors).toEqual([]);
+    expect(page.visibleViews()).toEqual(["address"]);
+    expect(page.node("address-balances").innerHTML).toContain("DAI");
+    expect(page.node("debug-banner")).toBeNull();
+
+    await backgroundSwitch(page, "sepolia");
+
+    const { state } = require("../src/shared/state");
+    expect(state.networkId).toBe("sepolia");
+    expect(state.rpcUrl).toBe(NETWORKS.sepolia.defaultRpcUrl);
+    expect(page.visibleViews()).toEqual(["address"]);
+    const balances = page.node("address-balances").innerHTML;
+    expect(balances).toContain("TST");
+    expect(balances).toContain("SepoliaETH");
+    expect(balances).not.toContain("DAI");
+    expect(page.text("debug-banner")).toBe("[TESTNET]");
+
+    // Its next refresh runs on Sepolia, and what it fetched is stored.
+    await page.tick();
+    const { refreshBalances } = require("../src/shared/balances");
+    expect(refreshBalances.mock.lastCall[4]).toBe("sepolia");
+    const stored = page.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.lastBalanceRefresh).toBeGreaterThan(0);
+});
+
+test("the popup open on Settings shows the new network, and Back draws the screen beneath for it", async () => {
+    const page = await bootOnAddress();
+    await page.click("btn-settings");
+    expect(page.visibleViews()).toEqual(["settings"]);
+
+    await backgroundSwitch(page, "sepolia");
+
+    expect(page.visibleViews()).toEqual(["settings"]);
+    expect(page.value("settings-network")).toBe("sepolia");
+    expect(page.value("settings-rpc")).toBe(NETWORKS.sepolia.defaultRpcUrl);
+    expect(page.node("settings-tracked-tokens").innerHTML).toContain("TST");
+    expect(page.text("debug-banner")).toBe("[TESTNET]");
+
+    await page.click("btn-settings-back");
+    expect(page.visibleViews()).toEqual(["address"]);
+    expect(page.node("address-balances").innerHTML).not.toContain("DAI");
+});
+
+// Neither can be drawn again for the new network: Send cannot be rendered from
+// saved state, and DAI was picked on Ethereum Mainnet, where alone it is
+// tracked. A reopened popup goes to Home in their place.
+test.each([
+    ["Send", (page) => page.click("btn-send")],
+    [
+        "AddressToken for DAI",
+        async (page) => {
+            const { state } = require("../src/shared/state");
+            state.selectedToken = MAINNET_TOKEN.address;
+            require("../src/popup/views/helpers").pushCurrentView();
+            require("../src/popup/views/addressToken").show();
+            await page.settle();
+        },
+    ],
+])("the popup open on %s goes to Home", async (_view, open) => {
+    const page = await bootOnAddress();
+    await open(page);
+    expect(page.visibleViews()).not.toEqual(["address"]);
+
+    await backgroundSwitch(page, "sepolia");
+
+    expect(page.visibleViews()).toEqual(["main"]);
+    expect(page.text("total-value")).toBe("0.0000 SepoliaETH");
+});
+
+// The report of the switch's own save names the network the page already has.
+test("a switch in Settings is not taken a second time when its save is reported", async () => {
+    const page = await bootOnAddress();
+    await page.click("btn-settings");
+    const { get, set } = page.storage.local;
+    const reads = get.mock.calls.length;
+    const writes = set.mock.calls.length;
+
+    const select = page.node("settings-network");
+    select.value = "sepolia";
+    for (const fn of select.listeners.change) await fn();
+    await page.settle();
+    await page.settle();
+
+    expect(get).toHaveBeenCalledTimes(reads + 1);
+    expect(set).toHaveBeenCalledTimes(writes + 1);
+    expect(page.text("flash-msg")).toBe("Switched to Sepolia Testnet.");
+});
+
+// The background saves the switch once the popup has read the stored record
+// and before it listens for changes to it, so the browser tells the page
+// nothing of it. Nor is any later write reported here: Chrome reports none
+// that leaves the record as it was, such as the popup's own save at start-up.
+test("a switch saved while the popup opens, before it listens for one, is followed", async () => {
+    const storage = makeStorageStub({ autistmask: profileOnAddress() });
+    storage.onChanged = { addListener: () => {} };
+    const read = storage.local.get.getMockImplementation();
+    storage.local.get.mockImplementationOnce(async (key) => {
+        const loaded = await read(key);
+        const record = storage.read("autistmask");
+        applyChainSwitchFields(record, "sepolia");
+        storage.write("autistmask", record);
+        return loaded;
+    });
+    const page = await bootPopup(undefined, { storage });
+    await page.settle();
+
+    const { state } = require("../src/shared/state");
+    expect(page.pageErrors).toEqual([]);
+    expect(state.networkId).toBe("sepolia");
+    expect(page.visibleViews()).toEqual(["address"]);
+    expect(page.node("address-balances").innerHTML).toContain("SepoliaETH");
+    expect(page.text("debug-banner")).toBe("[TESTNET]");
+});
+
+// While the popup's follow of the background's switch to Sepolia waits for the
+// lock, the user picks Sepolia in Settings and then Ethereum Mainnet again. The
+// last pick is the network stored, and the last one sites are told of.
+test("a switch in Settings made while a follow waits for the lock is not overwritten by it", async () => {
+    const page = await bootOnAddress();
+    await page.click("btn-settings");
+
+    // Another write holds the lock, so every save of the page waits for it.
+    let releaseLock;
+    const lockHeld = navigator.locks.request(
+        "autistmask",
+        () =>
+            new Promise((resolve) => {
+                releaseLock = resolve;
+            }),
+    );
+    await backgroundSwitch(page, "sepolia");
+    const select = page.node("settings-network");
+    const picks = [];
+    for (const networkId of ["sepolia", "mainnet"]) {
+        select.value = networkId;
+        for (const fn of select.listeners.change) picks.push(fn());
+    }
+    releaseLock();
+    await lockHeld;
+    await Promise.all(picks);
+    await page.settle();
+
+    const { state } = require("../src/shared/state");
+    expect(state.networkId).toBe("mainnet");
+    expect(page.storage.read("autistmask").networkId).toBe("mainnet");
+    expect(page.value("settings-network")).toBe("mainnet");
+    const told = globalThis.chrome.runtime.sendMessage.mock.calls
+        .map(([message]) => message)
+        .filter((message) => message.type === "AUTISTMASK_NETWORK_CHANGED");
+    expect(told.at(-1).chainId).toBe(NETWORKS.mainnet.chainId);
+});
+
+// The popup follows the background's switch to Sepolia, but its own write in
+// that save fails. The user then picks Ethereum Mainnet in Settings, the
+// network the popup was on before: that switch is stored, and only then
+// flashed and sent to sites.
+test("a switch back in Settings after a follow whose write failed is stored", async () => {
+    const page = await bootOnAddress();
+    await page.click("btn-settings");
+    const { set } = page.storage.local;
+    const write = set.getMockImplementation();
+    // The background's write lands; the next, the follow's, fails.
+    set.mockImplementationOnce(write).mockRejectedValueOnce(
+        new Error("quota exceeded"),
+    );
+    await backgroundSwitch(page, "sepolia");
+    const { state } = require("../src/shared/state");
+    expect(state.networkId).toBe("sepolia");
+
+    const select = page.node("settings-network");
+    select.value = "mainnet";
+    for (const fn of select.listeners.change) await fn();
+    await page.settle();
+
+    const stored = page.storage.read("autistmask");
+    expect(stored.networkId).toBe("mainnet");
+    expect(stored.rpcUrl).toBe(NETWORKS.mainnet.defaultRpcUrl);
+    expect(stored.trackedTokens).toEqual([MAINNET_TOKEN]);
+    expect(page.text("flash-msg")).toBe("Switched to Ethereum Mainnet.");
+    const told = globalThis.chrome.runtime.sendMessage.mock.calls
+        .map(([message]) => message)
+        .filter((message) => message.type === "AUTISTMASK_NETWORK_CHANGED");
+    expect(told.at(-1).chainId).toBe(NETWORKS.mainnet.chainId);
+});
+
+// Such as one a newer build wrote, which this build cannot read. Nothing reads
+// or writes the stored record for it: the popup's next save finds it, as
+// before.
+test("a record that names no network is not followed", async () => {
+    const page = await bootOnAddress();
+    const { get, set } = page.storage.local;
+    const reads = get.mock.calls.length;
+
+    await set({
+        autistmask: {
+            schemaVersion: STATE_SCHEMA_VERSION + 1,
+            wallets: [{ type: "hd", name: "Main", addresses: [] }],
+        },
+    });
+    await page.settle();
+
+    expect(get).toHaveBeenCalledTimes(reads);
+    expect(page.visibleViews()).toEqual(["address"]);
+});
+
+// A record that takes the switch from the switched record ends up as that
+// record, balances the background fetched since included.
+test("copyChainSwitchFields() takes every field applyChainSwitchFields() sets", () => {
+    const before = unversionedValidProfile({
+        trackedTokens: [MAINNET_TOKEN],
+        networkTrackedTokens: { sepolia: [SEPOLIA_TOKEN] },
+        networkEndpoints: {
+            sepolia: {
+                rpcUrl: "http://127.0.0.1:8545",
+                blockscoutUrl: "http://127.0.0.1:4000/api/v2",
+            },
+        },
+        lastBalanceRefresh: 1,
+        tokenHolderCache: { [MAINNET_TOKEN.address]: 5000 },
+        fraudContracts: ["0x1111111111111111111111111111111111111111"],
+    });
+    const switched = structuredClone(before);
+    applyChainSwitchFields(switched, "sepolia");
+    switched.wallets[0].addresses[0].balance = "2.0";
+
+    const follower = structuredClone(before);
+    copyChainSwitchFields(follower, switched);
+
+    expect(follower).toEqual(switched);
+});

tests/sendAmountRule.test.js

@@ -97,7 +97,7 @@ global.document = {
     body: { prepend() {}, appendChild() {} },
     addEventListener() {},
 };
-global.navigator = { clipboard: { writeText() {} } };
+global.navigator.clipboard = { writeText() {} };
 
 const { state } = require("../src/shared/state");
 const send = require("../src/popup/views/send");

tests/sendDisplayFloor.test.js

@@ -151,7 +151,7 @@ global.document = {
     body: { prepend() {}, appendChild() {} },
     addEventListener() {},
 };
-global.navigator = { clipboard: { writeText() {} } };
+global.navigator.clipboard = { writeText() {} };
 
 const { refreshBalances } = require("../src/shared/balances");
 const { state } = require("../src/shared/state");

tests/sendMax.test.js

@@ -146,7 +146,7 @@ global.document = {
     body: { prepend() {}, appendChild() {} },
     addEventListener() {},
 };
-global.navigator = { clipboard: { writeText() {} } };
+global.navigator.clipboard = { writeText() {} };
 
 const { Transaction, Wallet, formatEther } = require("ethers");
 const { refreshBalances } = require("../src/shared/balances");

tests/stateMerge.test.js

@@ -160,7 +160,7 @@ describe("the approval-window reproduction", () => {
         await approvalWindow.state.loadState();
         approvalWindow.helpers.showView("approve-tx");
         // showView() does not await its own saveState(); an extra save
-        // joins the same queue and only resolves once that one has too,
+        // waits for the lock behind that one and so resolves only after it,
         // which is the black-box way to know it landed.
         await approvalWindow.state.saveState();
 

tests/stateWriteLock.test.js

@@ -0,0 +1,96 @@
+// A popup save reads the stored record, merges this page's changes into it
+// and writes it back. The background's write of a network the user approved
+// used to be able to land between that read and that write, and the popup's
+// write then put the old network back
+// (https://git.eeqj.de/sneak/AutistMask/issues/641). Every write of the record
+// now holds a lock from its read to its write.
+//
+// The popup and the background run here as the real modules over one shared
+// storage stub, and share the lock the way the background and a page outside
+// a Firefox private window share the browser's
+// (tests/support/navigatorLocks.js).
+
+const { makeStorageStub } = require("./support/storageStub");
+
+function loadContexts(storage) {
+    jest.resetModules();
+    globalThis.chrome = { storage: { local: storage.local } };
+    return {
+        popup: require("../src/shared/state"),
+        background: require("../src/background/state"),
+        applyChainSwitchFields: require("../src/shared/chainSwitchFields")
+            .applyChainSwitchFields,
+    };
+}
+
+// Lets every pending promise callback run, and then some.
+function nextMacrotask() {
+    return new Promise((resolve) => setImmediate(resolve));
+}
+
+afterEach(() => {
+    delete globalThis.chrome;
+    jest.restoreAllMocks();
+});
+
+test("a network the background switches to during a popup save stays stored", async () => {
+    const storage = makeStorageStub({ autistmask: { networkId: "sepolia" } });
+    const { popup, background, applyChainSwitchFields } = loadContexts(storage);
+    await popup.loadState();
+
+    // The popup navigates, so its save has a change of its own to write.
+    popup.state.currentView = "settings";
+
+    // The popup's save has read the record and is about to write it back when
+    // the user's approval of a site's switch to mainnet reaches the
+    // background. Without the lock the background's whole update runs before
+    // the next macrotask; with it, the update waits for the popup's write.
+    let backgroundSwitch;
+    const realSet = storage.local.set.getMockImplementation();
+    storage.local.set.mockImplementationOnce(async (items) => {
+        backgroundSwitch = background.updateState((fresh) =>
+            applyChainSwitchFields(fresh, "mainnet"),
+        );
+        await nextMacrotask();
+        return realSet(items);
+    });
+
+    await popup.saveState();
+    await backgroundSwitch;
+
+    const stored = storage.read("autistmask");
+    expect(stored.networkId).toBe("mainnet");
+    expect(stored.currentView).toBe("settings");
+});
+
+test("after a save that failed, the next save still keeps a network the background switches to during it", async () => {
+    jest.spyOn(console, "error").mockImplementation(() => {});
+    const storage = makeStorageStub({ autistmask: { networkId: "sepolia" } });
+    const { popup, background, applyChainSwitchFields } = loadContexts(storage);
+    await popup.loadState();
+    popup.state.currentView = "settings";
+
+    // The first save's write is refused, so it gives the lock back having
+    // failed.
+    storage.local.set.mockRejectedValueOnce(new Error("quota exceeded"));
+    await expect(popup.saveState()).rejects.toThrow("quota exceeded");
+
+    // The next save is between its read and its write when the background
+    // switches to mainnet, as in the test above.
+    let backgroundSwitch;
+    const realSet = storage.local.set.getMockImplementation();
+    storage.local.set.mockImplementationOnce(async (items) => {
+        backgroundSwitch = background.updateState((fresh) =>
+            applyChainSwitchFields(fresh, "mainnet"),
+        );
+        await nextMacrotask();
+        return realSet(items);
+    });
+
+    await popup.saveState();
+    await backgroundSwitch;
+
+    const stored = storage.read("autistmask");
+    expect(stored.networkId).toBe("mainnet");
+    expect(stored.currentView).toBe("settings");
+});

tests/support/navigatorLocks.js

@@ -0,0 +1,27 @@
+// `navigator.locks` for the unit tests, which run on node, where there is none.
+//
+// One lock per name: granted in the order it was asked for, and let go when
+// the callback settles, whether it resolved or rejected. That is what the
+// browser's own does for the one call the extension makes,
+// `navigator.locks.request(name, callback)`. Every module a test file loads
+// shares it, as the extension's background and its pages share the browser's,
+// except a page in a Firefox private window (README, "Stored state and its
+// version").
+//
+// Run before each test file by `setupFiles` in package.json.
+
+// For each name, a promise that settles once the last request for it has
+// let the lock go.
+const released = new Map();
+
+function request(name, callback) {
+    const previous = released.get(name) || Promise.resolve();
+    const result = previous.then(() => callback({ name, mode: "exclusive" }));
+    released.set(
+        name,
+        result.catch(() => {}),
+    );
+    return result;
+}
+
+globalThis.navigator = { locks: { request } };

tests/support/popupBoot.js

@@ -311,7 +311,7 @@ async function bootPopup(stored, options) {
     const windowListeners = {};
 
     globalThis.chrome = {
-        storage: { local: storage.local },
+        storage: { local: storage.local, onChanged: storage.onChanged },
         runtime: {
             sendMessage: jest.fn(async () => ({})),
             getURL: (p) => "chrome-extension://autistmask/" + p,

tests/support/storageStub.js

@@ -18,7 +18,9 @@
 // a storage stub by hand.
 
 // One storage area: get, set and remove over its own store, cloning both ways.
-function makeArea(store, tick) {
+// `changed` is handed what each set or remove changed, in the shape
+// storage.onChanged reports it.
+function makeArea(store, tick, changed) {
     const get = jest.fn(async (key) => {
         tick();
         if (key === undefined || key === null) return structuredClone(store);
@@ -34,14 +36,25 @@ function makeArea(store, tick) {
 
     const set = jest.fn(async (items) => {
         tick();
+        const changes = {};
         for (const k of Object.keys(items)) {
+            changes[k] = structuredClone({
+                oldValue: store[k],
+                newValue: items[k],
+            });
             store[k] = structuredClone(items[k]);
         }
+        changed(changes);
     });
 
     const remove = jest.fn(async (key) => {
         tick();
-        for (const k of Array.isArray(key) ? key : [key]) delete store[k];
+        const changes = {};
+        for (const k of Array.isArray(key) ? key : [key]) {
+            changes[k] = { oldValue: store[k] };
+            delete store[k];
+        }
+        changed(changes);
     });
 
     return { get, set, remove };
@@ -54,12 +67,22 @@ function makeArea(store, tick) {
 function makeStorageStub(initial, onOp) {
     const store = initial ? structuredClone(initial) : {};
     const tick = onOp || (() => {});
-    const local = makeArea(store, tick);
+    // storage.onChanged: after a set or remove has finished, every listener is
+    // called with what it changed and the area's name, as the browser calls
+    // them for a write by any page or the background.
+    const listeners = [];
+    const announce = (areaName) => (changes) => {
+        Promise.resolve().then(() => {
+            for (const fn of listeners) fn(structuredClone(changes), areaName);
+        });
+    };
+    const local = makeArea(store, tick, announce("local"));
 
     return {
         // Drop this straight in as chrome.storage.
         local,
-        session: makeArea({}, tick),
+        session: makeArea({}, tick, announce("session")),
+        onChanged: { addListener: (fn) => listeners.push(fn) },
         get: local.get,
         set: local.set,
         remove: local.remove,
@@ -71,7 +94,9 @@ function makeStorageStub(initial, onOp) {
                 ? structuredClone(store)
                 : structuredClone(store[key]),
         // Seed or replace a record without going through the module under
-        // test — for standing in as "another page wrote this".
+        // test — for standing in as "another page wrote this". Nothing is
+        // announced to storage.onChanged, so it also stands in for the time
+        // before the browser tells this page of such a write.
         write: (key, value) => {
             store[key] = structuredClone(value);
         },

tests/trackedTokensPerNetwork.test.js

@@ -161,6 +161,7 @@ test("a token added by contract address on Sepolia is tracked on Sepolia only",
     );
     expect(stored().trackedTokens).toEqual([SEPOLIA_TOKEN]);
 
+    await boot.click("btn-settings");
     await chooseNetwork(boot, "mainnet");
     expect(stored().networkId).toBe("mainnet");
     expect(stored().trackedTokens).toEqual([MAINNET_TOKEN]);

tests/uniswapRecipient.test.js

@@ -7,9 +7,12 @@
 // (https://git.eeqj.de/sneak/AutistMask/issues/592), the address whose
 // balance a BALANCE_CHECK_ERC20 checks
 // (https://git.eeqj.de/sneak/AutistMask/issues/600), any token a swap
-// leaves in the router (https://git.eeqj.de/sneak/AutistMask/issues/606), and
+// leaves in the router (https://git.eeqj.de/sneak/AutistMask/issues/606),
 // what each PERMIT2_TRANSFER_FROM moves
-// (https://git.eeqj.de/sneak/AutistMask/issues/611).
+// (https://git.eeqj.de/sneak/AutistMask/issues/611), and when an
+// UNWRAP_WETH makes the output ETH
+// (https://git.eeqj.de/sneak/AutistMask/issues/607 and
+// https://git.eeqj.de/sneak/AutistMask/issues/642).
 //
 // Every swap command, SWEEP, WRAP_ETH, UNWRAP_WETH, TRANSFER, PAY_PORTION,
 // PAY_PORTION_FULL_PRECISION, PERMIT2_TRANSFER_FROM, ACROSS_V4_DEPOSIT_V3 and
@@ -268,18 +271,28 @@ const SWAP_USDT_FOR_ETH = [
         [[[ZERO, USDT, 500, 10, ZERO], false, USDT_2000, ONE_WETH, "0x"]],
     ),
 ];
+const SWAP_USDT_FOR_WETH = [
+    0x06, // SWAP_EXACT_IN_SINGLE
+    coder.encode(
+        [
+            "tuple(tuple(address,address,uint24,int24,address),bool,uint128,uint128,bytes)",
+        ],
+        [[[USDT, WETH, 500, 10, ZERO], true, USDT_2000, ONE_WETH, "0x"]],
+    ),
+];
 // SWAP_EXACT_IN_SINGLE with no parameters, which cannot be read.
 const UNREADABLE_SWAP = [0x06, "0x"];
 const SETTLE_USDT = [
     0x0b,
     coder.encode(["address", "uint256", "bool"], [USDT, 0n, true]),
 ];
-function take(currency, recipient) {
+// A TAKE of `amount`, by default zero: the open delta, all the step owes.
+function take(currency, recipient, amount = 0n) {
     return [
         0x0e,
         coder.encode(
             ["address", "address", "uint256"],
-            [currency, recipient, 0n],
+            [currency, recipient, amount],
         ),
     ];
 }
@@ -387,6 +400,18 @@ describe("each swap command's recipient", () => {
             data: (r) => execute(swapToWeth(r)),
             min: "1.0000 WETH",
         },
+        {
+            // Its input has V3_SWAP_EXACT_IN's layout, with amountOut and
+            // amountInMax in place of amountIn and amountOutMin, and a path
+            // that lists the token bought first.
+            kind: "V3_SWAP_EXACT_OUT",
+            data: (r) =>
+                execute([
+                    0x01,
+                    v3SwapExactIn(r, ONE_WETH, USDT_2000, WETH, USDT)[1],
+                ]),
+            min: "1.0000 WETH",
+        },
         {
             kind: "V4_SWAP with TAKE",
             data: (r) =>
@@ -519,7 +544,7 @@ describe("an output left in the router is not received", () => {
         {
             kind: "an UNWRAP_WETH to the user, then the swap",
             data: execute(unwrapWeth(MSG_SENDER), toRouter),
-            min: "1.0000 ETH",
+            min: "1.0000 WETH",
         },
         {
             kind: "the swap, then a WRAP_ETH of zero to the user",
@@ -556,6 +581,530 @@ describe("an output left in the router is not received", () => {
     });
 });
 
+// https://git.eeqj.de/sneak/AutistMask/issues/607: an UNWRAP_WETH pays out,
+// as ETH, the WETH the router holds when it runs. Token Out read ETH whenever
+// the output side was WETH, so a swap that paid its WETH to the user before
+// the UNWRAP_WETH read as ETH, though the user receives WETH.
+describe("an UNWRAP_WETH makes the output ETH only when the router holds it", () => {
+    test("a swap paying its WETH to the user, then an UNWRAP_WETH, reads as WETH", () => {
+        const result = decode(
+            execute(swapToWeth(MSG_SENDER), unwrapWeth(MSG_SENDER)),
+        );
+        expect(result.name).toBe("Swap USDT → WETH");
+        expect(labels(result)).toEqual(PAID_TO_USER);
+        expect(detail(result, "Min. received").value).toBe("1.0000 WETH");
+    });
+
+    test("a swap paying its WETH to the router, then an UNWRAP_WETH to the user, reads as ETH", () => {
+        const result = decode(
+            execute(swapToWeth(ADDRESS_THIS), unwrapWeth(MSG_SENDER)),
+        );
+        expect(result.name).toBe("Swap USDT → ETH");
+        expect(labels(result)).toEqual(PAID_TO_USER);
+        expect(detail(result, "Min. received").value).toBe("1.0000 ETH");
+    });
+
+    // The SWEEP pays the user all the WETH the router holds, so the
+    // UNWRAP_WETH finds none of it.
+    test("a swap paying its WETH to the router, then a SWEEP of it to the user, then an UNWRAP_WETH, reads as WETH", () => {
+        const result = decode(
+            execute(
+                swapToWeth(ADDRESS_THIS),
+                sweep(WETH, MSG_SENDER),
+                unwrapWeth(MSG_SENDER),
+            ),
+        );
+        expect(result.name).toBe("Swap USDT → WETH");
+        expect(detail(result, "Min. received").value).toBe("1.0000 WETH");
+    });
+
+    // The user receives the first step's WETH as WETH and the second's as
+    // ETH. The second step sets the output side and pays its WETH to the
+    // router, so the output reads as ETH with the second step's minimum.
+    test("two swaps, the second paying its WETH to the router, then an UNWRAP_WETH, reads as ETH", () => {
+        const result = decode(
+            execute(
+                swapToWeth(MSG_SENDER),
+                v2Swap(0x08, ADDRESS_THIS, USDC_1990, ONE_WETH / 2n, [
+                    USDC,
+                    WETH,
+                ]),
+                unwrapWeth(MSG_SENDER),
+            ),
+        );
+        expect(result.name).toBe("Swap USDT → ETH");
+        expect(detail(result, "Min. received").value).toBe("0.5000 ETH");
+    });
+
+    // The same two swaps the other way round. The user receives the first
+    // step's WETH as ETH and the second's as WETH. The second step sets the
+    // output side and pays its WETH to the user, so the output reads as WETH
+    // with the second step's minimum, though the router holds the first's.
+    test("two swaps, the second paying its WETH to the user, then an UNWRAP_WETH, reads as WETH", () => {
+        const result = decode(
+            execute(
+                v2Swap(0x08, ADDRESS_THIS, USDC_1990, ONE_WETH / 2n, [
+                    USDC,
+                    WETH,
+                ]),
+                swapToWeth(MSG_SENDER),
+                unwrapWeth(MSG_SENDER),
+            ),
+        );
+        expect(result.name).toBe("Swap USDC → WETH");
+        expect(detail(result, "Min. received").value).toBe("1.0000 WETH");
+    });
+
+    // One V4 step buys at least 1 WETH and TAKEs 0.6 WETH to the user and the
+    // rest to the router. The user receives 0.6 WETH and the rest as ETH.
+    // Neither minimum is shown: the decoder does not count how much of the
+    // step's minimum reaches the router, nor read the UNWRAP_WETH's own.
+    test("one V4 step paying part of its WETH to the user and the rest to the router, then an UNWRAP_WETH, 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),
+            ),
+        );
+        expect(result.name).toBe("Swap USDT → ETH");
+        expect(labels(result)).toEqual([
+            "Protocol",
+            "Token In",
+            "Amount",
+            "Token Out",
+            "Steps",
+            "Deadline",
+        ]);
+    });
+
+    // 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(
+            execute(
+                v4Swap(
+                    SWAP_USDT_FOR_WETH,
+                    SETTLE_USDT,
+                    withDirtyWord(take(WETH, MSG_SENDER), 1),
+                    take(WETH, ADDRESS_THIS),
+                ),
+                unwrapWeth(MSG_SENDER),
+            ),
+        );
+        expect(result.name).toBe("Swap USDT → ETH");
+        expect(detail(result, "Min. received")).toBeUndefined();
+        expect(detail(result, "Min. paid out")).toBeUndefined();
+    });
+
+    // A step after the UNWRAP_WETH that sets the output side sets it anew.
+    test("a swap paying WETH to the user after an UNWRAP_WETH of an earlier swap's WETH reads as WETH", () => {
+        const result = decode(
+            execute(
+                swapToWeth(ADDRESS_THIS),
+                unwrapWeth(MSG_SENDER),
+                v2Swap(0x08, MSG_SENDER, USDC_1990, ONE_WETH / 2n, [
+                    USDC,
+                    WETH,
+                ]),
+            ),
+        );
+        expect(result.name).toBe("Swap USDT → WETH");
+        expect(detail(result, "Min. received").value).toBe("0.5000 WETH");
+    });
+
+    // The EXECUTE_SUB_PLAN's own steps, which the decoder does not read, buy
+    // the user USDC as well, so Token Out is not named.
+    test("a swap paying its WETH to the router, then an UNWRAP_WETH, then an EXECUTE_SUB_PLAN, names no Token Out", () => {
+        const subPlan = [
+            0x21,
+            coder.encode(
+                ["bytes", "bytes[]"],
+                [
+                    "0x00",
+                    [
+                        v3SwapExactIn(
+                            MSG_SENDER,
+                            USDT_2000,
+                            USDC_1990,
+                            USDT,
+                            USDC,
+                        )[1],
+                    ],
+                ],
+            ),
+        ];
+        const result = decode(
+            execute(swapToWeth(ADDRESS_THIS), unwrapWeth(MSG_SENDER), subPlan),
+        );
+        expect(result.name).toBe("Uniswap Swap");
+        expect(detail(result, "Token Out").value).toBe(UNDECODED);
+        expect(detail(result, "Min. received")).toBeUndefined();
+    });
+});
+
+// https://git.eeqj.de/sneak/AutistMask/issues/642: a step between the swap and
+// the UNWRAP_WETH may take WETH out of the router or pay it WETH, and a step
+// after an UNWRAP_WETH into the router may pay its ETH out as WETH, yet each
+// route read as ETH with the swap's minimum. A step the decoder read that is a
+// PERMIT2_PERMIT, a BALANCE_CHECK_ERC20, or a SWEEP, TRANSFER, PAY_PORTION or
+// PAY_PORTION_FULL_PRECISION of a token other than WETH, and not of ETH to a
+// WETH contract, cannot take WETH out of the router or pay anyone WETH; the
+// decoder treats every other step as one that may.
+describe("what reaches the UNWRAP_WETH of the swap's WETH", () => {
+    const NO_MINIMUM_TO_USER = PAID_TO_USER.filter(
+        (l) => l !== "Min. received",
+    );
+    const NO_MINIMUM_ELSEWHERE = PAID_ELSEWHERE.filter(
+        (l) => l !== "Min. paid out",
+    );
+
+    test.each([
+        {
+            kind: "a TRANSFER of 0.0025 WETH",
+            step: transfer(0x05, WETH, OTHER, ONE_WETH / 400n),
+        },
+        {
+            kind: "a PAY_PORTION of 25 bips",
+            step: transfer(0x06, WETH, OTHER, 25n),
+        },
+        {
+            kind: "a PAY_PORTION_FULL_PRECISION of 1e15",
+            step: transfer(0x07, WETH, OTHER, 10n ** 15n),
+        },
+    ])(
+        "$kind to another address between them reads as ETH with no minimum",
+        ({ step }) => {
+            const result = decode(
+                execute(swapToWeth(ADDRESS_THIS), step, unwrapWeth(MSG_SENDER)),
+                USER,
+                ROUTER_V2_1_2,
+            );
+            expect(result.name).toBe("Swap USDT → ETH");
+            expect(labels(result)).toEqual(NO_MINIMUM_ELSEWHERE);
+            expect(paidTo(result)).toEqual([OTHER]);
+        },
+    );
+
+    test.each([
+        {
+            kind: "a SWEEP whose recipient cannot be read",
+            step: withDirtyWord(sweep(WETH, OTHER), 1),
+        },
+        {
+            kind: "a V4 SETTLE of 0.5 WETH from the router",
+            step: v4Swap([
+                0x0b,
+                coder.encode(
+                    ["address", "uint256", "bool"],
+                    [WETH, ONE_WETH / 2n, false],
+                ),
+            ]),
+        },
+        {
+            kind: "a bridge deposit of 0.5 WETH",
+            step: acrossDeposit(USER, USER, WETH, ONE_WETH / 2n),
+        },
+        {
+            kind: "a PERMIT2_TRANSFER_FROM of 0.5 WETH into the router",
+            step: permit2TransferFrom(WETH, ADDRESS_THIS, ONE_WETH / 2n),
+        },
+    ])("$kind between them reads as ETH with no minimum", ({ step }) => {
+        const result = decode(
+            execute(swapToWeth(ADDRESS_THIS), step, unwrapWeth(MSG_SENDER)),
+        );
+        expect(result.name).toBe("Swap USDT → ETH");
+        expect(detail(result, "Min. received")).toBeUndefined();
+        expect(detail(result, "Min. paid out")).toBeUndefined();
+    });
+
+    test.each([
+        {
+            kind: "a PERMIT2_PERMIT between them",
+            steps: [permit2Permit(USDT, USDT_2000), unwrapWeth(MSG_SENDER)],
+        },
+        {
+            kind: "a BALANCE_CHECK_ERC20 of another address between them",
+            steps: [balanceCheck(USDC, 1n, OTHER), unwrapWeth(MSG_SENDER)],
+        },
+        {
+            kind: "a BALANCE_CHECK_ERC20 of the sender with a zero minimum between them",
+            steps: [balanceCheck(USDC, 0n), unwrapWeth(MSG_SENDER)],
+        },
+        {
+            kind: "a SWEEP of USDC between them",
+            steps: [sweep(USDC, MSG_SENDER), unwrapWeth(MSG_SENDER)],
+        },
+        {
+            kind: "an UNWRAP_WETH into the router, then a SWEEP of its ETH,",
+            steps: [unwrapWeth(ADDRESS_THIS), sweep(ZERO, MSG_SENDER)],
+        },
+    ])("$kind reads as ETH with the swap's minimum", ({ steps }) => {
+        const result = decode(execute(swapToWeth(ADDRESS_THIS), ...steps));
+        expect(result.name).toBe("Swap USDT → ETH");
+        expect(detail(result, "Min. received").value).toBe("1.0000 ETH");
+    });
+
+    test("a V4 step that TAKEs its WETH to the router, then an UNWRAP_WETH to the user, reads as ETH with the swap's minimum", () => {
+        const result = decode(
+            execute(
+                v4Swap(
+                    SWAP_USDT_FOR_WETH,
+                    SETTLE_USDT,
+                    take(WETH, ADDRESS_THIS),
+                ),
+                unwrapWeth(MSG_SENDER),
+            ),
+        );
+        expect(result.name).toBe("Swap USDT → ETH");
+        expect(detail(result, "Min. received").value).toBe("1.0000 ETH");
+    });
+
+    test.each([
+        {
+            kind: "a TRANSFER of 100 USDC",
+            step: transfer(0x05, USDC, OTHER, 100000000n),
+        },
+        {
+            kind: "a PAY_PORTION of 25 bips of USDC",
+            step: transfer(0x06, USDC, OTHER, 25n),
+        },
+        {
+            kind: "a PAY_PORTION_FULL_PRECISION of 1e15 of USDC",
+            step: transfer(0x07, USDC, OTHER, 10n ** 15n),
+        },
+    ])(
+        "$kind to another address between them reads as ETH with the swap's minimum",
+        ({ step }) => {
+            const result = decode(
+                execute(swapToWeth(ADDRESS_THIS), step, unwrapWeth(MSG_SENDER)),
+                USER,
+                ROUTER_V2_1_2,
+            );
+            expect(result.name).toBe("Swap USDT → ETH");
+            expect(paidTo(result)).toEqual([OTHER]);
+            expect(detail(result, "Min. paid out").value).toBe("1.0000 ETH");
+        },
+    );
+
+    test.each([
+        {
+            kind: "a TRANSFER of 0.0025 ETH",
+            step: transfer(0x05, ZERO, OTHER, ONE_WETH / 400n),
+        },
+        {
+            kind: "a PAY_PORTION of 25 bips of its ETH",
+            step: transfer(0x06, ZERO, OTHER, 25n),
+        },
+        {
+            kind: "a PAY_PORTION_FULL_PRECISION of 1e15 of its ETH",
+            step: transfer(0x07, ZERO, OTHER, 10n ** 15n),
+        },
+    ])(
+        "an UNWRAP_WETH into the router, then $kind to another address, then a SWEEP of its ETH to the user, reads as ETH with the swap's minimum",
+        ({ step }) => {
+            const result = decode(
+                execute(
+                    swapToWeth(ADDRESS_THIS),
+                    unwrapWeth(ADDRESS_THIS),
+                    step,
+                    sweep(ZERO, MSG_SENDER),
+                ),
+                USER,
+                ROUTER_V2_1_2,
+            );
+            expect(result.name).toBe("Swap USDT → ETH");
+            expect(paidTo(result)).toEqual([OTHER]);
+            expect(detail(result, "Min. paid out").value).toBe("1.0000 ETH");
+        },
+    );
+
+    // The SWEEP pays the user the swap's WETH, so the UNWRAP_WETH unwraps the
+    // WRAP_ETH's.
+    test("a SWEEP of the swap's WETH to the user, then a WRAP_ETH into the router, reads as ETH with no minimum", () => {
+        const result = decode(
+            execute(
+                swapToWeth(ADDRESS_THIS),
+                sweep(WETH, MSG_SENDER),
+                wrapEth(ADDRESS_THIS, ONE_WETH),
+                unwrapWeth(MSG_SENDER),
+            ),
+        );
+        expect(result.name).toBe("Swap USDT → ETH");
+        expect(labels(result)).toEqual(NO_MINIMUM_TO_USER);
+    });
+
+    test("an UNWRAP_WETH into the router, then a WRAP_ETH of all its ETH to the user, reads as WETH with no minimum", () => {
+        const result = decode(
+            execute(
+                swapToWeth(ADDRESS_THIS),
+                unwrapWeth(ADDRESS_THIS),
+                wrapEth(MSG_SENDER, CONTRACT_BALANCE),
+            ),
+        );
+        expect(result.name).toBe("Swap USDT → WETH");
+        expect(labels(result)).toEqual(NO_MINIMUM_TO_USER);
+    });
+
+    // The router reads the recipient from the last 20 bytes of its word,
+    // here address(2), the router itself.
+    test("an UNWRAP_WETH whose recipient cannot be read, then a WRAP_ETH of all the router's ETH to the user, reads as WETH with no minimum", () => {
+        const result = decode(
+            execute(
+                swapToWeth(ADDRESS_THIS),
+                withDirtyWord(unwrapWeth(ADDRESS_THIS), 0),
+                wrapEth(MSG_SENDER, CONTRACT_BALANCE),
+            ),
+        );
+        expect(result.name).toBe("Swap USDT → WETH");
+        expect(detail(result, "Min. received")).toBeUndefined();
+        expect(detail(result, "Min. paid out")).toBeUndefined();
+    });
+
+    // The first UNWRAP_WETH may pay the router the swap's output as ETH, and
+    // the WRAP_ETH to the user pays all of it out as WETH, so the last
+    // UNWRAP_WETH finds none of it.
+    test.each([
+        {
+            kind: "an UNWRAP_WETH whose recipient cannot be read, then a WRAP_ETH of all the router's ETH to the user",
+            steps: [
+                withDirtyWord(unwrapWeth(ADDRESS_THIS), 0),
+                wrapEth(MSG_SENDER, CONTRACT_BALANCE),
+            ],
+        },
+        {
+            kind: "an UNWRAP_WETH into the router, a WRAP_ETH of all its ETH to the user, then a WRAP_ETH of all its ETH into the router",
+            steps: [
+                unwrapWeth(ADDRESS_THIS),
+                wrapEth(MSG_SENDER, CONTRACT_BALANCE),
+                wrapEth(ADDRESS_THIS, CONTRACT_BALANCE),
+            ],
+        },
+    ])(
+        "$kind, then an UNWRAP_WETH to the user, reads as WETH with no minimum",
+        ({ steps }) => {
+            const result = decode(
+                execute(
+                    swapToWeth(ADDRESS_THIS),
+                    ...steps,
+                    unwrapWeth(MSG_SENDER),
+                ),
+            );
+            expect(result.name).toBe("Swap USDT → WETH");
+            expect(detail(result, "Min. received")).toBeUndefined();
+            expect(detail(result, "Min. paid out")).toBeUndefined();
+        },
+    );
+
+    // A SWEEP of WETH pays out WETH, and ETH paid to a WETH contract pays the
+    // router WETH for it. The decoder treats each as a step that may pay out
+    // as WETH the swap's output, which the router holds as ETH.
+    test.each([
+        {
+            kind: "a SWEEP of WETH to the user",
+            step: sweep(WETH, MSG_SENDER),
+        },
+        {
+            kind: "a SWEEP of its ETH to the WETH contract",
+            step: sweep(ZERO, WETH),
+        },
+        {
+            kind: "a TRANSFER of 0.5 ETH to the WETH contract",
+            step: transfer(0x05, ZERO, WETH, ONE_WETH / 2n),
+        },
+        {
+            kind: "a PAY_PORTION of all its ETH to the WETH contract",
+            step: transfer(0x06, ZERO, WETH, 10000n),
+        },
+    ])(
+        "an UNWRAP_WETH into the router, then $kind, reads as WETH with no minimum",
+        ({ step }) => {
+            const result = decode(
+                execute(
+                    swapToWeth(ADDRESS_THIS),
+                    unwrapWeth(ADDRESS_THIS),
+                    step,
+                ),
+            );
+            expect(result.name).toBe("Swap USDT → WETH");
+            expect(detail(result, "Min. received")).toBeUndefined();
+            expect(detail(result, "Min. paid out")).toBeUndefined();
+        },
+    );
+
+    // The user receives 0.5 WETH and the rest of the swap's output as ETH.
+    test("an UNWRAP_WETH into the router, then a WRAP_ETH of 0.5 ETH to the user, reads as WETH with no minimum", () => {
+        const result = decode(
+            execute(
+                swapToWeth(ADDRESS_THIS),
+                unwrapWeth(ADDRESS_THIS),
+                wrapEth(MSG_SENDER, ONE_WETH / 2n),
+                sweep(ZERO, MSG_SENDER),
+            ),
+        );
+        expect(result.name).toBe("Swap USDT → WETH");
+        expect(labels(result)).toEqual(NO_MINIMUM_TO_USER);
+    });
+
+    // The UNWRAP_WETH pays the user the swap's WETH as ETH; the WRAP_ETH wraps
+    // the ETH an earlier V4 step paid the router.
+    test("an UNWRAP_WETH to the user, then a WRAP_ETH of all the router's ETH to the user, reads as ETH", () => {
+        const result = decode(
+            execute(
+                v4Swap(
+                    SWAP_USDT_FOR_ETH,
+                    SETTLE_USDT,
+                    take(ZERO, ADDRESS_THIS),
+                ),
+                swapToWeth(ADDRESS_THIS),
+                unwrapWeth(MSG_SENDER),
+                wrapEth(MSG_SENDER, CONTRACT_BALANCE),
+            ),
+        );
+        expect(detail(result, "Token Out").value).toBe("ETH");
+        expect(detail(result, "Min. received").value).toBe("1.0000 ETH");
+    });
+
+    // The first swap is for at least 0.5 WETH and the second for at least
+    // 1 WETH. The second sets the output side again, so the first
+    // UNWRAP_WETH into the router no longer bears on it.
+    test.each([
+        { kind: "a V3 swap step", step: swapToWeth(ADDRESS_THIS) },
+        {
+            kind: "a V4 step that TAKEs its WETH to the router",
+            step: v4Swap(
+                SWAP_USDT_FOR_WETH,
+                SETTLE_USDT,
+                take(WETH, ADDRESS_THIS),
+            ),
+        },
+    ])(
+        "a swap paying WETH to the router, an UNWRAP_WETH into the router, a SWEEP of its ETH to the user, then $kind and an UNWRAP_WETH to the user, reads as ETH with the second swap's minimum",
+        ({ step }) => {
+            const result = decode(
+                execute(
+                    v3SwapExactIn(
+                        ADDRESS_THIS,
+                        USDT_2000,
+                        ONE_WETH / 2n,
+                        USDT,
+                        WETH,
+                    ),
+                    unwrapWeth(ADDRESS_THIS),
+                    sweep(ZERO, MSG_SENDER),
+                    step,
+                    unwrapWeth(MSG_SENDER),
+                ),
+            );
+            expect(result.name).toBe("Swap USDT → ETH");
+            expect(detail(result, "Min. received").value).toBe("1.0000 ETH");
+        },
+    );
+});
+
 // https://git.eeqj.de/sneak/AutistMask/issues/606: any token a step pays the
 // router stays there unless a later step pays out or spends all of it, not
 // only the swap's output. A V4 SETTLE can take more of the user's tokens than
@@ -671,6 +1220,7 @@ describe("any token left in the router is not received", () => {
                 v3SwapExactIn(MSG_SENDER, USDT_2000, USDC_1990, USDT, USDC),
             ),
             left: tokenLine(WETH, "WETH"),
+            spent: "2000.0000 USDT",
         },
         {
             kind: "a WRAP_ETH of 1 ETH into the router, then a swap of 0.5 WETH from the router",
@@ -697,6 +1247,7 @@ describe("any token left in the router is not received", () => {
                 v2Swap(0x08, MSG_SENDER, ONE_WETH, USDC_1990, [WETH, USDC]),
             ),
             left: tokenLine(WETH, "WETH"),
+            spent: "1.0000 WETH",
         },
         {
             kind: "a WRAP_ETH of 1 ETH into the router, then a V3 swap of 1 WETH that the user pays for",
@@ -705,6 +1256,7 @@ describe("any token left in the router is not received", () => {
                 v3SwapExactIn(MSG_SENDER, ONE_WETH, USDC_1990, WETH, USDC),
             ),
             left: tokenLine(WETH, "WETH"),
+            spent: "1.0000 WETH",
         },
         {
             kind: "a WRAP_ETH of 1 ETH into the router, then a V4 swap of 1 WETH with a SETTLE of 1 WETH by the user",
@@ -717,6 +1269,7 @@ describe("any token left in the router is not received", () => {
                 ),
             ),
             left: tokenLine(WETH, "WETH"),
+            spent: "1.0000 WETH",
         },
         {
             kind: "a swap paying WETH to the router, a WRAP_ETH of 1 ETH into the router, then a swap of 1 WETH from the router",
@@ -792,9 +1345,13 @@ describe("any token left in the router is not received", () => {
                 ),
             ),
             left: tokenLine(WETH, "WETH"),
+            // The step has two SETTLEs of WETH, so what the user pays is not
+            // known.
+            spent: UNDECODED,
         },
         // The user pays for the swap by a SETTLE_ALL or SETTLE whose currency
-        // the decoder cannot read, so the SETTLE from the router pays nothing.
+        // the decoder cannot read, so the SETTLE from the router pays nothing,
+        // and what the user pays is not known.
         {
             kind: "a WRAP_ETH of 1 ETH into the router, then a V4 swap of 1 WETH with a SETTLE_ALL that cannot be read and a SETTLE of OPEN_DELTA from the router",
             data: execute(
@@ -807,6 +1364,7 @@ describe("any token left in the router is not received", () => {
                 ),
             ),
             left: tokenLine(WETH, "WETH"),
+            unread: true,
         },
         {
             kind: "a WRAP_ETH of 1 ETH into the router, then a V4 swap of 1 WETH with a SETTLE by the user that cannot be read and a SETTLE of OPEN_DELTA from the router",
@@ -820,6 +1378,7 @@ describe("any token left in the router is not received", () => {
                 ),
             ),
             left: tokenLine(WETH, "WETH"),
+            unread: true,
         },
         {
             kind: "a WRAP_ETH of 1 ETH into the router, then a V4 step with an exact-in of 1 WETH less 1,000 wei and an empty path, a swap of 1,000 wei, and a SETTLE of OPEN_DELTA from the router",
@@ -873,12 +1432,29 @@ describe("any token left in the router is not received", () => {
             ),
             left: { label: "Token moved into the router", value: "ETH" },
         },
-    ])("$kind", ({ data, left }) => {
+    ])("$kind", ({ data, left, spent, unread }) => {
         const result = decode(data);
         expect(labels(result)).toEqual([
             "Protocol",
             "Token In",
-            "Amount",
+            // A later step whose SETTLE or SETTLE_ALL the decoder cannot read
+            // may take anything from the sender: one line says so, in place
+            // of the Amount line (https://git.eeqj.de/sneak/AutistMask/issues/625),
+            // after the lines the WRAP_ETH's 1 ETH then gets
+            // (https://git.eeqj.de/sneak/AutistMask/issues/659).
+            ...(unread
+                ? [
+                      "Moved from the sender",
+                      "Token moved",
+                      "Moved to",
+                      "Moved from the sender",
+                  ]
+                : ["Amount"]),
+            // A later swap step the user pays for spends `spent` of a token
+            // other than Token In.
+            ...(spent
+                ? ["Moved from the sender", "Token moved", "Moved to"]
+                : []),
             "Token Out",
             "Paid to",
             "Token moved into the router",
@@ -886,6 +1462,16 @@ describe("any token left in the router is not received", () => {
             "Steps",
             "Deadline",
         ]);
+        if (spent) {
+            expect(detail(result, "Moved from the sender").value).toBe(spent);
+        }
+        if (unread) {
+            expect(
+                result.details
+                    .filter((d) => d.label === "Moved from the sender")
+                    .map((d) => d.value),
+            ).toEqual(["1.0000 ETH", UNDECODED]);
+        }
         expect(paidTo(result)).toEqual([STAYS_IN_ROUTER]);
         expect(detail(result, "Token moved into the router")).toEqual(left);
         expect(detail(result, "Min. paid out").value).toBe("1990.0000 USDC");
@@ -1496,15 +2082,6 @@ describe("a payout of part of the router's output", () => {
             ),
             min: "1.0000 WETH",
         },
-        {
-            kind: "PAY_PORTION of 25 bips, then UNWRAP_WETH",
-            data: execute(
-                swapToWeth(ADDRESS_THIS),
-                transfer(0x06, WETH, OTHER, 25n),
-                unwrapWeth(MSG_SENDER),
-            ),
-            min: "1.0000 ETH",
-        },
         {
             kind: "V4 TAKE_PORTION of 25 bips, then TAKE_ALL",
             data: execute(
@@ -1993,10 +2570,6 @@ describe("a payout that cannot be read is never said to be received", () => {
                 ),
             ],
         },
-        {
-            kind: "V3_SWAP_EXACT_OUT",
-            step: [0x01, swapToWeth(OTHER)[1]],
-        },
         {
             kind: "EXECUTE_SUB_PLAN",
             step: [
@@ -2229,26 +2802,37 @@ describe("the allow-revert flag", () => {
     });
 
     // Only the routers from UniversalRouterV2 on let a PERMIT2_PERMIT fail.
+    // The permit's spender is the router at ROUTER, which on every other
+    // router is an allowance to another spender, so the minimum reads
+    // Min. paid out there.
     test.each([
-        { router: "UniversalRouterV1", address: ROUTER_V1, mark: "" },
+        {
+            router: "UniversalRouterV1",
+            address: ROUTER_V1,
+            mark: "",
+            minimum: "Min. paid out",
+        },
         {
             router: "UniversalRouterV1_2_V2Support",
             address: ROUTER_V1_2,
             mark: "",
+            minimum: "Min. paid out",
         },
         {
             router: "UniversalRouterV2",
             address: ROUTER,
             mark: " (allowed to fail)",
+            minimum: "Min. received",
         },
         {
             router: "UniversalRouterV2_1_2",
             address: ROUTER_V2_1_2,
             mark: " (allowed to fail)",
+            minimum: "Min. paid out",
         },
     ])(
-        "on $router, a PERMIT2_PERMIT with the flag is listed as 'Permit2 Permit$mark', and the swap reads as without the flag",
+        "on $router, a PERMIT2_PERMIT with the flag is listed as 'Permit2 Permit$mark', and the swap's lines read as without the flag",
-        ({ address, mark }) => {
+        ({ address, mark, minimum }) => {
             const steps = [
                 permit2Permit(USDT, USDT_2000),
                 swapToWeth(MSG_SENDER),
@@ -2262,10 +2846,25 @@ describe("the allow-revert flag", () => {
             expect(detail(withFlag, "Steps").value).toBe(
                 "Permit2 Permit" + mark + " → V3 Swap (Exact In)",
             );
-            const withoutSteps = (r) =>
+            // The permit names the router at ROUTER as its spender, so its
-                r.details.filter((d) => d.label !== "Steps");
+            // amount stands as the Amount figure only there, and only without
-            expect(withoutSteps(withFlag)).toEqual(withoutSteps(plain));
+            // the flag. With the flag it stands on no router and gets lines
-            expect(detail(withFlag, "Min. received").value).toBe("1.0000 WETH");
+            // of its own, and the swap step names Token In: the same token,
+            // its address written the same way.
+            const permitLines = [
+                "Permit2 allowance",
+                "Allowance token",
+                "Allowance spender",
+            ];
+            const swapLines = (r) =>
+                r.details.filter(
+                    (d) => !["Steps", ...permitLines].includes(d.label),
+                );
+            expect(swapLines(withFlag)).toEqual(swapLines(plain));
+            expect(
+                labels(withFlag).filter((l) => permitLines.includes(l)),
+            ).toEqual(permitLines);
+            expect(detail(withFlag, minimum).value).toBe("1.0000 WETH");
         },
     );
 

tests/uniswapRouterAddress.test.js

@@ -7,6 +7,12 @@
 // only when the transaction is sent to a Universal Router deployment on the
 // network it is for; anywhere else it is left to the raw data.
 //
+// The transaction history labelled any call named `execute` or `multicall` a
+// Swap, whatever address it went to
+// (https://git.eeqj.de/sneak/AutistMask/issues/580). It now does so only for
+// such a call sent to a Universal Router deployment on the network the
+// transaction is on; any other is labelled by its method name.
+//
 // The transaction detail screen and the approval screen are driven against a
 // minimal DOM stub in the shape tests/tokenTransferDetail.test.js uses, the
 // approval screen opened the way tests/swapStatusAmount.test.js opens it.
@@ -33,6 +39,7 @@ globalThis.chrome = {
 };
 
 const { state } = require("../src/shared/state");
+const { fetchRecentTransactions } = require("../src/shared/transactions");
 const approval = require("../src/popup/views/approval");
 const { decodeCalldata } = approval;
 const transactionDetail = require("../src/popup/views/transactionDetail");
@@ -47,6 +54,8 @@ const SEPOLIA_ROUTER = "0x3a9d48ab9751398bbfa63ad67599bb04e4bdf98b";
 const ROUTER_ON_BOTH = "0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD";
 // The address with no code from the issue.
 const ORDINARY = "0x0b0050Da68435b3EcBC236c40F16dB2070bCD79A";
+// A contract that is not a router, such as a multisig.
+const OTHER_CONTRACT = "0x5afe000000000000000000000000000000005afe";
 
 const RECIPIENT = "0xC0FfEE0000000000000000000000000000c0fFEe";
 const SEPOLIA_WETH = "0xfFf9976782d46CC05630D1f6eBAb18b2324d6B14";
@@ -129,8 +138,13 @@ describe("execute() calldata on the approval screen's decoder", () => {
 // The transaction the explorer reports: SWAP_DATA, sent to `mockSentTo`.
 const TX_HASH = "0x" + "5".repeat(64);
 let mockSentTo = null;
+// The transactions the explorer reports for RECIPIENT's history.
+let mockHistory = [];
 
 function mockExplorerAnswer(url) {
+    if (url.endsWith("/addresses/" + RECIPIENT + "/transactions")) {
+        return { items: mockHistory };
+    }
     if (url.endsWith("/transactions/" + TX_HASH)) {
         return {
             to: { hash: mockSentTo },
@@ -187,10 +201,9 @@ function node(id) {
 }
 
 // Open the transaction detail screen with `activeNetworkId` active, for the
-// Sepolia transaction the explorer reports sent to `sentTo`, and wait for its
+// history row `row`, and wait for its decoded details.
-// decoded details.
+async function showDetail(row, activeNetworkId) {
-async function showDetailSentTo(sentTo, activeNetworkId) {
+    mockSentTo = row.to;
-    mockSentTo = sentTo;
     globalThis.document = makeDocument();
     globalThis.window = { location: { search: "" } };
     state.networkId = activeNetworkId;
@@ -198,22 +211,32 @@ async function showDetailSentTo(sentTo, activeNetworkId) {
     state.viewData = {};
     state.viewStack = [];
     state.currentView = null;
-    transactionDetail.show({
+    transactionDetail.show(row);
-        hash: TX_HASH,
-        from: RECIPIENT,
-        to: sentTo,
-        value: "",
-        symbol: "SepoliaETH",
-        timestamp: 1790000000,
-        isError: false,
-        direction: "contract",
-        directionLabel: "Swap",
-        method: "execute",
-        chainId: SEPOLIA,
-    });
     for (let i = 0; i < 10; i++) await new Promise((r) => setTimeout(r, 0));
 }
 
+// Open the transaction detail screen with `activeNetworkId` active, for the
+// Sepolia transaction the explorer reports sent to `sentTo`, and wait for its
+// decoded details.
+async function showDetailSentTo(sentTo, activeNetworkId) {
+    await showDetail(
+        {
+            hash: TX_HASH,
+            from: RECIPIENT,
+            to: sentTo,
+            value: "",
+            symbol: "SepoliaETH",
+            timestamp: 1790000000,
+            isError: false,
+            direction: "contract",
+            directionLabel: "Swap",
+            method: "execute",
+            chainId: SEPOLIA,
+        },
+        activeNetworkId,
+    );
+}
+
 describe("execute() calldata on the transaction detail screen", () => {
     test("sent to a router on the active network, it is a swap", async () => {
         await showDetailSentTo(SEPOLIA_ROUTER, "sepolia");
@@ -245,6 +268,58 @@ describe("execute() calldata on the transaction detail screen", () => {
     });
 });
 
+// The history row made from the explorer's answer for RECIPIENT's `method`
+// call sent to the contract `sentTo` on the network with `chainId`. The
+// explorer gives the address in checksummed form.
+async function historyRow(method, sentTo, chainId) {
+    mockHistory = [
+        {
+            hash: TX_HASH,
+            block_number: 7000000,
+            timestamp: "2026-09-01T00:00:00Z",
+            from: { hash: RECIPIENT },
+            to: { hash: getAddress(sentTo), is_contract: true },
+            value: "0",
+            method,
+            status: "ok",
+        },
+    ];
+    const rows = await fetchRecentTransactions(
+        RECIPIENT,
+        "https://explorer.example/api/v2",
+        chainId,
+    );
+    return rows[0];
+}
+
+// The history row's label and TransactionDetail's Type line, for a Sepolia
+// transaction. The active network does not decide either.
+describe.each([
+    ["execute", "Execute"],
+    ["multicall", "Multicall"],
+])("a %s() call in the history", (method, methodLabel) => {
+    test("sent to a router on its network, it is a Swap", async () => {
+        const row = await historyRow(method, SEPOLIA_ROUTER, SEPOLIA);
+        expect(row.directionLabel).toBe("Swap");
+        await showDetail(row, "mainnet");
+        expect(node("tx-detail-type").textContent).toBe("Swap");
+    });
+
+    test("sent to another contract, it is labelled by its method name", async () => {
+        const row = await historyRow(method, OTHER_CONTRACT, SEPOLIA);
+        expect(row.directionLabel).toBe(methodLabel);
+        await showDetail(row, "sepolia");
+        expect(node("tx-detail-type").textContent).toBe("Contract Call");
+    });
+
+    test("sent to a router of the other network only, it is labelled by its method name", async () => {
+        const row = await historyRow(method, MAINNET_ROUTER, SEPOLIA);
+        expect(row.directionLabel).toBe(methodLabel);
+        await showDetail(row, "mainnet");
+        expect(node("tx-detail-type").textContent).toBe("Contract Call");
+    });
+});
+
 // Open the approval screen with Ethereum Mainnet active, for a site's Sepolia
 // transaction that sends SWAP_DATA to `sentTo`.
 async function showApprovalSentTo(sentTo) {

tests/unknownScaleSend.test.js

@@ -120,7 +120,7 @@ global.document = {
     body: { prepend() {}, appendChild() {} },
     addEventListener() {},
 };
-global.navigator = { clipboard: { writeText() {} } };
+global.navigator.clipboard = { writeText() {} };
 
 const { AbiCoder, parseUnits } = require("ethers");
 const { fetchTokenBalances } = require("../src/shared/balances");

tests/walletDefects.test.js

@@ -475,7 +475,7 @@ describe("every way to a signature or the private key refuses a defective wallet
                 to: RECIPIENT,
                 value: "0x0",
                 data: "0x",
-                chainId: 1,
+                chainId: "0x1",
                 nonce: 0,
                 gasLimit: "21000",
                 maxFeePerGas: "1000000000",