docs: rewrite README.md sentence by sentence against the prose rules (closes #672)

Rewrites README.md from scratch for
#672: what the program is, how
to use it, every setting, the design, then development and tests. Every
statement was checked against the code on next. Where the old text and
the code disagreed, the code decides; the PR body lists each
disagreement and judgement call.

Model: fable-5-1

Dockerfile

@@ -10,6 +10,7 @@ WORKDIR /app
 
 COPY script/ script/
 COPY package.json yarn.lock ./
+# yarn warns about the workspaces field in eslint and babel-plugin-istanbul; no newer release drops it.
 RUN script/bootstrap
 
 COPY . .

docs/RELEASE.md

@@ -1,87 +1,225 @@
 # Releasing AutistMask
 
-This is the procedure that turns a green `main` into a tagged, packaged release.
-It gathers into one place what is otherwise spread across the `Makefile` and
-three `README.md` sections, so the person cutting a release does not have to
-reconstruct the order from them.
+A release is a tagged commit on the `main` branch and the two archives that
+`make package` writes from that commit. This file is the procedure, in order.
 
-There is one version, declared in three files (`package.json`,
-`manifest/chrome.json`, `manifest/firefox.json`), and `make package` builds and
-packages but publishes nothing. `make build` and `make package` can be run by
-anyone; tagging, signing, packing a CRX and any upload need credentials only the
-owner ([@sneak](https://sneak.berlin)) holds and are marked **owner-only**
-below. Releases are tagged from `main` (see the Workflow section of `TODO.md`),
-so the "release commit" throughout is the `main` commit the milestone PR merged.
+Only the owner ([@sneak](https://sneak.berlin)):
+
+- decides whether and when a release is tagged;
+- creates, moves or deletes a tag;
+- decides where the archives are published.
+
+Anyone can run steps 1 to 4. No script in this repository uploads or publishes
+the archives. None signs them, and none packs a CRX (Chrome's packaged extension
+file).
+
+## Terms
+
+- The tracker is the repository's Gitea site (Gitea is the software that hosts
+  the repository): https://git.eeqj.de/sneak/AutistMask. The tracker's Actions
+  page, https://git.eeqj.de/sneak/AutistMask/actions, lists the workflow runs.
+- A workflow is a file under `.gitea/workflows/` that lists jobs. The tracker
+  runs every workflow on each push. Each job runs one script on the tracker's
+  runner (the machine that runs jobs).
+- The release commit is a commit on `main`. Releases are tagged from `main` only
+  (`TODO.md`, Workflow).
+- A clean checkout is a working tree (the checked-out files) at the release
+  commit where `git status --porcelain` prints nothing. The build stamps the
+  commit hash (the commit's id) into the extension and appends `-dirty` when the
+  tree has local changes.
+- A tag is a name that git attaches to one commit. Release tags read `vX.Y.Z`,
+  such as `v0.1.0`.
+- A digest is the sha256 hash of a file (a fixed-length fingerprint of its
+  bytes), written as 64 hexadecimal characters.
+
+## What you need
+
+- A clean checkout of the release commit.
+- `make`.
+- Docker (a tool that runs programs in containers), for `script/cibuild` in
+  step 1. `make package` needs no Docker.
+- Node and yarn, on the `PATH`. `make package` runs both directly.
+  `script/bootstrap` can install both through nvm (a Node version manager), but
+  it leaves them off the `PATH`.
 
 ## Procedure
 
-1. **Confirm `main` is green in CI.** The `check` workflow
-   (`.gitea/workflows/check.yml`) runs `script/cibuild`, which runs
-   `script/check` and then builds the image uncached, so a green `check` run is
-   a green `make check`. Find the run for the exact release commit on the
-   tracker's Actions view. _Check:_ that commit's `check` run succeeded; running
-   `make check` on a clean checkout of the commit reproduces it and exits 0.
+### 1. Confirm the release commit is green
 
-2. **Confirm the version matches the intended tag.** `package.json`,
-   `manifest/chrome.json` and `manifest/firefox.json` must all declare the same
-   `X.Y.Z`. `make build` fails when they disagree, but nothing checks that they
-   equal the tag you mean to create — that is this manual step. _Check:_ all
-   three files read the same `X.Y.Z`, and it is the version you intend to tag
-   `vX.Y.Z`.
+The `check` workflow (`.gitea/workflows/check.yml`) runs `script/cibuild` on
+every push. `script/cibuild` runs:
 
-3. **Build and package from a clean checkout of that commit.** From a fresh
-   clone, or a working tree with no local modifications (`git status` clean),
-   checked out at the release commit: run `make setup`, then `make package`.
-   `make package` runs `make build` first, so the archives can only be made from
-   a `dist/` verified against that build's own receipt as a release (not debug)
-   build. It writes three files into `release/`:
-   `autistmask-chrome-<version>.zip`, `autistmask-firefox-<version>.xpi`, and
-   `SHA256SUMS`. _Check:_ those three files exist and `<version>` in the archive
-   names is the version confirmed in step 2. The Firefox `.xpi` is **unsigned**
-   (see step 6 and "Installing on Firefox" in `README.md`).
+- `script/bootstrap`, which installs the dependencies;
+- `script/check`, which is what `make check` runs;
+- the Docker image build (an image is Docker's packaged form of a program).
 
-4. **Verify `SHA256SUMS`.** The archives are deterministic — sorted entries,
-   fixed timestamps, fixed compression — so a second `make package` from another
-   clean checkout of the same commit produces byte-identical files. Verify the
-   recorded digests against the files with `sha256sum -c SHA256SUMS`, run from
-   `release/`. To confirm reproducibility, run `make package` again on a
-   separate clean checkout and compare the digests. _Check:_ `sha256sum -c`
-   reports `OK` for every file, and an independent build's digests match.
+`script/check` runs:
 
-5. **Tag the release commit.** _(owner-only)_ Create an annotated tag `vX.Y.Z`
-   on the release commit and push it: `git tag -a vX.Y.Z` (with a message), then
-   `git push origin vX.Y.Z`. _Check:_ `git tag` lists `vX.Y.Z`, and
-   `git rev-parse vX.Y.Z^{commit}` resolves to the release commit.
+- `script/test`: the tests, in Docker;
+- `script/lint`, which runs three checks in Docker:
+    - ESLint, a code checker;
+    - `prettier --check .`, the formatting check;
+    - `script/check-censored`, which fails when the name that `RULES.md` bars
+      appears outside its allowed places;
+- `script/fmt-check`: `prettier --check .` again, on the host.
 
-6. **Distribute per browser.** _(owner-only; pending the owner's choice on
-   https://git.eeqj.de/sneak/AutistMask/issues/386)_ How 1.0.0 is distributed on
-   each browser is not yet decided; it is the open question on that issue, and
-   the concrete steps cannot be written until the owner records a choice there.
-   These steps need credentials only the owner holds. The options under
-   consideration are:
-    - **Firefox** — the packaged `.xpi` is unsigned, and release Firefox and ESR
-      refuse an unsigned add-on:
-        - (a) AMO self-distribution signing (unlisted): submit the `.xpi` to AMO
-          with the owner's credentials; AMO returns a signed `.xpi` installable
-          on every Firefox, with nothing listed publicly.
-        - (b) AMO listed: as (a), plus a public AMO listing and review.
-        - (c) Ship the unsigned `.xpi` and state that Firefox support means
-          Developer Edition, Nightly, or an Unbranded build with
-          `xpinstall.signatures.required` set to `false`.
-    - **Chrome** — the repo packs no CRX and publishes nothing; the extension id
-      is fixed by the `key` in `manifest/chrome.json`:
-        - (a) Chrome Web Store (unlisted): upload the `.zip` with the owner's
-          developer account; the store delivers installs and updates.
-        - (b) Self-hosted CRX signed with the private key the owner holds
-          (`chrome --pack-extension=dist/chrome --pack-extension-key=<path to the .pem>`),
-          installable only via enterprise policy on Windows and macOS, so
-          realistically Linux-only.
-        - (c) "Load unpacked" from `dist/chrome/` only, as today.
+The `e2e` workflow (`.gitea/workflows/e2e.yml`) has two jobs. One runs
+`script/test-e2e`, the browser tests in Chrome. The other runs
+`script/test-e2e-firefox`, the browser tests in Firefox. A red `e2e` job does
+not fail the `check` run.
 
-    Once the owner decides, the chosen steps — including which credentials they
-    need and who holds them — are written into this section and `README.md`'s
-    installation sections are updated to match, which is part of the definition
-    of done of https://git.eeqj.de/sneak/AutistMask/issues/386. _Check:_ for a
-    store or AMO route, the artifact installs from the store or AMO on a clean
-    browser profile; for the CRX or unpacked route, the documented load succeeds
-    and Chrome reports the extension id `gipbhkogfopeahplcjhipkgpcimdpkip`.
+Run `script/cibuild` on the clean checkout. `script/cibuild` runs the same steps
+as the `check` run, and must exit 0.
+
+Check: on the Actions page, the `check` run for the release commit succeeded,
+and both `e2e` jobs for that commit succeeded. `script/cibuild` exited 0 on the
+clean checkout.
+
+### 2. Confirm the version
+
+Three files declare the version:
+
+- `package.json`;
+- `manifest/chrome.json`;
+- `manifest/firefox.json`.
+
+`script/lib/version.js` fails the build when the three disagree.
+`tests/version.test.js` fails when the version is not three numbers separated by
+dots. Nothing compares the version with a tag. That comparison is this step.
+
+Check: all three files read the same `X.Y.Z`, and `vX.Y.Z` is the tag that the
+owner creates in step 5.
+
+### 3. Build and package
+
+On the clean checkout, run:
+
+```bash
+make setup
+make package
+```
+
+`make setup` installs two things:
+
+- the dependencies, from the lockfile `yarn.lock`, which pins each one's
+  version;
+- the git pre-commit hook, a script that git runs before each commit. Here the
+  hook runs `script/check`.
+
+`make package` runs `make build`, then `script/lib/package.js`.
+
+`make build`:
+
+- runs `build.js`. `build.js` writes `dist/chrome/`, `dist/firefox/` and a build
+  receipt. The receipt lists every file that `build.js` wrote, with each file's
+  digest. The receipt lives outside the repository and is deleted when the build
+  ends;
+- runs `script/verify-build --expect release` against the receipt. The check
+  fails when:
+    - `dist/` differs from the receipt;
+    - a bundle (one JavaScript file built from many source files) was compiled
+      with the build-time constant `DEBUG` on;
+    - any file carries the test recovery phrase, which a debug build gives every
+      new wallet;
+- runs `script/check-censored --require-dist` against the built files;
+- removes `dist/` when any of those steps fails.
+
+`script/lib/package.js`:
+
+- empties `release/`;
+- refuses a symbolic link (a file that points at another file) under `dist/`;
+- checks that the browser's directory (`dist/chrome/` or `dist/firefox/`) holds
+  every file named in `manifest.json` or in the popup's HTML page.
+  `manifest.json` is the file that describes the extension to the browser. The
+  popup is the window that the toolbar button opens;
+- checks that the `version` in each `manifest.json` is the version from step 2;
+- writes one archive per browser;
+- reads each archive back;
+- compares every member (a file inside the archive) with `dist/` byte for byte;
+- writes `SHA256SUMS`, with one line per archive:
+    - the digest;
+    - two spaces;
+    - the file name.
+
+`make package` writes three files:
+
+```
+release/autistmask-chrome-<version>.zip
+release/autistmask-firefox-<version>.xpi
+release/SHA256SUMS
+```
+
+The `.xpi` is Firefox's add-on package file (an add-on is Firefox's word for an
+extension). The `.xpi` is not signed.
+
+`make package` prints a line that starts `Not shipped` and names `styles.css`.
+This is expected: each archive holds its own copy of the stylesheet.
+
+Check: `release/` holds those three files, and `<version>` in their names is the
+version from step 2.
+
+### 4. Verify the digests
+
+From `release/`, run `sha256sum -c SHA256SUMS`.
+
+The archives are deterministic for a given `dist/`: the same `dist/` always
+gives the same bytes. `script/lib/zip.js`:
+
+- sorts the members;
+- sets every member's timestamp (its recorded date) to 1980-01-01;
+- compresses each member the same way every time.
+
+`dist/` itself carries the build date. `build.js` compiles the build date, a UTC
+(universal time) day, into the extension. So two builds of the same commit on
+the same UTC day give byte-identical archives. Builds on different days differ.
+
+Check: `sha256sum -c` prints `OK` for both archives. On the same UTC day, a
+second `make package` from another clean checkout of the same commit gives the
+same `SHA256SUMS`.
+
+### 5. Tag the release commit
+
+Owner only. Only the owner decides whether and when a release is tagged. Only
+the owner creates, moves or deletes a tag. On the release commit, the owner
+runs:
+
+```bash
+git tag -a vX.Y.Z -m "AutistMask X.Y.Z"
+git push origin vX.Y.Z
+```
+
+`-a` makes an annotated tag: a tag that carries a message and records who made
+the tag and when. `v0.1.0` is one.
+
+Once the tag exists, `git describe --tags` on the release commit prints
+`vX.Y.Z`. `script/cibuild` and `script/docker` pass that value to the Docker
+image build as `VERSION`.
+
+Check: `git rev-parse vX.Y.Z^{commit}` prints the release commit's hash, and the
+tag is listed at https://git.eeqj.de/sneak/AutistMask/tags.
+
+### 6. Publish the archives
+
+Owner only. The owner decides where the archives are published. No script in
+this repository uploads or publishes them.
+
+Whoever receives an archive installs it as follows.
+
+Chrome loads the extension from a directory:
+
+- unzip the archive into a new, empty directory, for example
+  `unzip autistmask-chrome-0.1.0.zip -d autistmask-chrome`;
+- open `chrome://extensions/` and turn on "Developer mode";
+- click "Load unpacked" and pick that directory.
+
+Chrome then reports the extension id `gipbhkogfopeahplcjhipkgpcimdpkip`. The id
+is the fixed string that identifies the extension to Chrome; the `key` in
+`manifest/chrome.json` sets the id.
+
+Release builds of Firefox refuse to install an unsigned add-on. Desktop Firefox
+115 or newer, in any edition, loads the `.xpi` as a temporary add-on from the
+`about:debugging` page. Firefox unloads a temporary add-on when Firefox exits.
+The section "Installing on Firefox" in `README.md` has the details.
+
+Check: each archive installs on a fresh browser profile (a new, empty set of
+browser data) by the route above.

eslint.config.js

@@ -153,8 +153,7 @@ module.exports = [
         },
     },
 
-    // The helpers the script/ entrypoints call: plain node programs too, run
-    // from a shell script rather than from yarn, and never bundled.
+    // The files in script/lib/ run on plain node too, and are never bundled.
     {
         files: ["script/lib/**/*.js"],
         languageOptions: {

package.json

@@ -6,8 +6,8 @@
     "license": "GPL-3.0",
     "private": true,
     "scripts": {
-        "test": "jest --forceExit --maxWorkers=3",
-        "test:verbose": "jest --forceExit --maxWorkers=3 --verbose",
+        "test": "node script/lib/jest.js --maxWorkers=3",
+        "test:verbose": "node script/lib/jest.js --maxWorkers=3 --verbose",
         "build": "node build.js",
         "lint": "eslint . && prettier --check .",
         "fmt": "prettier --write .",

script/bootstrap

@@ -118,6 +118,7 @@ ensure_yarn() {
     fi
 }
 
+# yarn warns about the workspaces field in eslint and babel-plugin-istanbul; no newer release drops it.
 install_js_deps() {
     if missing yarn && [ -s "$HOME/.nvm/nvm.sh" ]; then
         nvm_sh "nvm use $NODE_VERSION >/dev/null && cd \"$ROOT\" && \

script/lib/jest.js

@@ -0,0 +1,40 @@
+// Runs jest with the arguments it is given, and fails the run when jest had to
+// force-stop the worker process that ran a test file. Jest itself only prints a
+// warning when that happens, and its run still passes. The warning means a test
+// left a timer or another open handle running. The test scripts in package.json
+// run jest through this file.
+//
+// Jest runs inside this process and writes to the terminal directly, so its
+// output looks the same as a plain jest run. This file only checks each write
+// to stderr for the warning below.
+
+"use strict";
+
+// The start of the warning that jest prints on stderr after it force-stops a
+// worker process.
+const WORKER_WARNING = "A worker process has failed to exit gracefully";
+
+let forceStopped = false;
+
+const writeStderr = process.stderr.write.bind(process.stderr);
+process.stderr.write = (chunk, ...rest) => {
+    if (String(chunk).includes(WORKER_WARNING)) {
+        forceStopped = true;
+    }
+    return writeStderr(chunk, ...rest);
+};
+
+// Runs after jest has finished, as the process exits.
+process.on("exit", () => {
+    if (forceStopped) {
+        console.error(
+            "script/lib/jest.js: failing the run, because jest force-stopped " +
+                "a worker process. A test left a timer or another open " +
+                "handle running.",
+        );
+        process.exitCode = 1;
+    }
+});
+
+// Jest's own command-line program. It reads its arguments from process.argv.
+require("jest/bin/jest");

src/popup/index.js

@@ -6,6 +6,7 @@ const {
     saveState,
     onSaveFailure,
     takeStoredNetwork,
+    clearBalanceNotFetched,
     loadState,
 } = require("../shared/state");
 const { StateUnusableError } = require("../shared/stateSchema");
@@ -65,7 +66,14 @@ function renderWalletList() {
 const pageClosed = new AbortController();
 window.addEventListener("pagehide", () => pageClosed.abort());
 
+// While a refresh runs, a request through ctx is not dropped. The request sets
+// refreshAgain, and one more refresh runs once the running one ends. Several
+// requests in that time lead to one more refresh, not several. An import asks
+// for a refresh after its address scan. A refresh already running does not
+// have the addresses the scan found
+// (https://git.eeqj.de/sneak/AutistMask/issues/581).
 let refreshInFlight = false;
+let refreshAgain = false;
 
 // The ten-second refresh startRefresh() starts, stopped when the popup moves to
 // the recovery screen: there is no profile left to refresh.
@@ -88,14 +96,28 @@ let refreshTimer = null;
 // removed meanwhile is left as it is. Blockscout may have answered before the
 // user turned "Use Blockscout" off. So the save drops every token the user has
 // not tracked if the stored setting is off by then.
+//
+// The save also deletes `balanceNotFetched` from each tracked token whose
+// balance this refresh read at every address. trackToken() in
+// src/popup/views/helpers.js sets that field. The save takes the field off the
+// matching tokens of the stored record (clearBalanceNotFetched() in
+// src/shared/state.js). The rest of the stored tracked token list stays as it
+// is.
+//
+// Once the save is done, the wallet list is drawn again. So are the balances
+// on AddressDetail or AddressToken when that screen is up. No other screen is
+// drawn again, DeleteAddress and its balance lines included.
 async function doRefreshAndRender() {
-    if (refreshInFlight) return;
+    if (refreshInFlight) {
+        refreshAgain = true;
+        return;
+    }
     refreshInFlight = true;
     try {
         await followStoredSettings();
         const networkId = state.networkId;
         const wallets = structuredClone(state.wallets);
-        await Promise.all([
+        const [, readTokens] = await Promise.all([
             refreshPrices(pageClosed.signal),
             refreshBalances(
                 wallets,
@@ -127,33 +149,43 @@ async function doRefreshAndRender() {
             if (!stored.useBlockscout) {
                 dropUntrackedTokens(state.wallets, stored.trackedTokens);
             }
+            clearBalanceNotFetched(stored, readTokens);
             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
-        // reject: an unhandled rejection is not a report of anything. The save
-        // inside it reports its own failure through onSaveFailure() (see
-        // src/shared/state.js); what is left here is a failed network round
-        // trip, which the next tick retries.
+        // No caller waits for this function, so it must never reject. An
+        // unhandled rejection reports nothing. The save inside it reports its
+        // own failure through onSaveFailure() (see src/shared/state.js); what
+        // is left here is a failed network round trip, which the next tick
+        // retries.
         log.errorf("popup: background refresh failed:", e);
     } finally {
         refreshInFlight = false;
     }
+    if (refreshAgain) {
+        refreshAgain = false;
+        doRefreshAndRender();
+    }
 }
 
 // Refreshes now and every ten seconds from then on. Called once a wallet
 // exists: by init() when the popup opens with one, and by AddWallet when it
 // adds one, which in a popup that opened on Welcome is the first
-// (https://git.eeqj.de/sneak/AutistMask/issues/530). With the refresh already
-// running it starts no second one, and on the recovery screen it does nothing.
+// (https://git.eeqj.de/sneak/AutistMask/issues/530). With the ten-second
+// refresh already started, it starts no second one. On the recovery screen it
+// does nothing.
 function startRefresh() {
     if (!$("view-state-recovery").classList.contains("hidden")) return;
     doRefreshAndRender();
     if (refreshTimer === null) {
-        refreshTimer = setInterval(doRefreshAndRender, 10000);
+        // A tick that finds a refresh running is dropped.
+        refreshTimer = setInterval(() => {
+            if (!refreshInFlight) return doRefreshAndRender();
+        }, 10000);
     }
 }
 

src/popup/views/addToken.js

@@ -1,11 +1,24 @@
-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");
 const { isScamAddress } = require("../../shared/scamlist");
+const { isSpoofedSymbol } = require("../../shared/symbolSpoof");
 const { log } = require("../../shared/log");
 
+// Counts the times AddToken has opened. A contract lookup started before
+// AddToken was last opened changes neither the screen nor the status line.
+let addTokenScreenOpenings = 0;
+
 function show() {
+    addTokenScreenOpenings++;
     $("add-token-address").value = "";
     $("add-token-info").textContent = "";
     $("add-token-info").style.visibility = "hidden";
@@ -55,6 +68,7 @@ function init(ctx) {
         // The network the lookup asks, which Settings may switch away from
         // before it answers, as for a transaction in confirmTx.js.
         const chainId = currentNetwork().chainId;
+        const opening = addTokenScreenOpenings;
         try {
             const info = await lookupTokenInfo(
                 contractAddr,
@@ -71,8 +85,17 @@ function init(ctx) {
                 );
                 return;
             }
+            // The balance list never shows a token that the spoof rule
+            // refuses, so such a token is not tracked.
+            if (isSpoofedSymbol(info.symbol, contractAddr, chainId)) {
+                showFlash("Not added: this token fakes a known symbol.");
+                if (addTokenScreenOpenings !== opening) return;
+                infoEl.textContent = "";
+                infoEl.style.visibility = "hidden";
+                return;
+            }
             log.infof("Adding token", info.symbol, contractAddr);
-            state.trackedTokens.push({
+            trackToken({
                 address: contractAddr,
                 symbol: info.symbol,
                 decimals: info.decimals,
@@ -80,6 +103,17 @@ function init(ctx) {
             });
             await saveState();
             ctx.doRefreshAndRender();
+            // If the lookup answers after AddToken was opened again, the
+            // token is still added, but the screen and the status line stay
+            // as they are.
+            if (addTokenScreenOpenings !== opening) return;
+            // The lookup is over, so a later Back onto AddToken shows no
+            // status.
+            infoEl.textContent = "";
+            infoEl.style.visibility = "hidden";
+            // If the lookup answers while another screen shows, the token is
+            // still added but the screen does not change.
+            if (state.currentView !== "add-token") return;
             // Pop the stack (back to address detail) and re-render it
             // so the newly added token is visible immediately.
             if (state.viewStack.length > 0) {
@@ -100,6 +134,7 @@ function init(ctx) {
                     ? detail
                     : "Could not add the token.",
             );
+            if (addTokenScreenOpenings !== opening) return;
             infoEl.textContent = "";
             infoEl.style.visibility = "hidden";
         }

src/popup/views/addressDetail.js

@@ -22,6 +22,7 @@ const {
     filterTransactions,
 } = require("../../shared/transactions");
 const { resolveEnsNames } = require("../../shared/ens");
+const { storedNetworkIs } = require("../../shared/storedSettings");
 const {
     updateSendBalance,
     renderSendTokenSelect,
@@ -66,11 +67,27 @@ 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();
+    // Only Blockscout reports the tokens the user has not tracked.
+    $("address-tokens-note").classList.toggle("hidden", !!state.useBlockscout);
+    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,
@@ -84,13 +101,6 @@ function show() {
                 ctx.showAddressToken();
             });
         });
-    // Only Blockscout reports the tokens the user has not tracked.
-    $("address-tokens-note").classList.toggle("hidden", !!state.useBlockscout);
-    renderSendTokenSelect(addr);
-    $("tx-list").innerHTML =
-        '<div class="text-muted text-xs py-1">Loading...</div>';
-    showView("address");
-    loadTransactions(addr.address);
 }
 
 let loadedTxs = [];
@@ -98,6 +108,7 @@ let loadedTxs = [];
 let ensNameMap = new Map();
 
 async function loadTransactions(address) {
+    const networkId = state.networkId;
     try {
         const rawTxs = await fetchRecentTransactions(
             address,
@@ -114,43 +125,74 @@ async function loadTransactions(address) {
         });
         const txs = result.transactions;
 
-        // Persist any newly discovered fraud contracts
-        if (result.newFraudContracts.length > 0) {
-            for (const addr of result.newFraudContracts) {
-                if (!state.fraudContracts.includes(addr)) {
-                    state.fraudContracts.push(addr);
-                }
-            }
-            await saveState();
-        }
-
-        loadedTxs = txs;
-
         // Collect ALL unique addresses (from + to) for ENS resolution so
         // that reverse lookups work for every displayed address, not just
         // the ones that were originally entered as ENS names.
         const counterparties = [
             ...new Set(txs.flatMap((tx) => [tx.from, tx.to].filter(Boolean))),
         ];
+        let names = new Map();
         if (counterparties.length > 0) {
             try {
-                ensNameMap = await resolveEnsNames(
+                names = await resolveEnsNames(
                     counterparties,
                     state.rpcUrl,
                     state.networkId,
                     ctx.pageClosed,
                 );
             } catch {
-                ensNameMap = new Map();
+                // The rows then show no ENS names.
             }
         }
 
+        // If the network changed during the lookups above, or the screen now
+        // shows another address, nothing is saved or drawn. See
+        // src/shared/storedSettings.js.
+        if (
+            state.networkId !== networkId ||
+            !(await storedNetworkIs(networkId)) ||
+            $("address-line").dataset.full !== address
+        ) {
+            return;
+        }
+
+        // Persist any newly discovered fraud contracts, inside the save and
+        // holding the lock. Nothing is added unless this page and the stored
+        // record both still name the request's network.
+        if (result.newFraudContracts.length > 0) {
+            let saved = false;
+            await saveState((stored) => {
+                if (state.networkId !== networkId) return false;
+                if (stored.networkId !== networkId) return false;
+                for (const addr of result.newFraudContracts) {
+                    if (!state.fraudContracts.includes(addr)) {
+                        state.fraudContracts.push(addr);
+                    }
+                }
+                saved = true;
+            });
+            // If the network changed while the save waited for the lock,
+            // nothing is drawn.
+            if (!saved) return;
+        }
+
+        loadedTxs = txs;
+        ensNameMap = names;
         renderTransactions(txs);
     } catch (e) {
         // Cancelled by the popup closing, not failed: see pageClosed in
         // src/popup/index.js.
         if (ctx.pageClosed.aborted) return;
         log.errorf("loadTransactions failed:", e.message);
+        // If the network changed, or the screen now shows another address,
+        // the failure is not shown.
+        if (
+            state.networkId !== networkId ||
+            !(await storedNetworkIs(networkId)) ||
+            $("address-line").dataset.full !== address
+        ) {
+            return;
+        }
         $("tx-list").innerHTML =
             '<div class="text-muted text-xs py-1">Failed to load transactions.</div>';
     }
@@ -287,4 +329,4 @@ function init(_ctx) {
     exportPrivkey.init();
 }
 
-module.exports = { init, show };
+module.exports = { init, show, renderBalances };

src/popup/views/addressToken.js

@@ -22,13 +22,14 @@ const {
     timeAgo,
 } = require("./helpers");
 const { state, saveState, currentNetwork } = require("../../shared/state");
-const { TOKEN_BY_ADDRESS, resolveSymbol } = require("../../shared/tokenList");
+const { bundledToken, resolveSymbol } = require("../../shared/tokenList");
 const { formatUsd, getPrice } = require("../../shared/prices");
 const {
     fetchRecentTransactions,
     filterTransactions,
 } = require("../../shared/transactions");
 const { resolveEnsNames } = require("../../shared/ens");
+const { storedNetworkIs } = require("../../shared/storedSettings");
 const {
     updateSendBalance,
     renderSendTokenSelect,
@@ -49,37 +50,24 @@ 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") {
-        symbol = nativeCurrency();
-        amount = parseFloat(addr.balance || "0");
-        price = getPrice("ETH");
-    } 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(tokenId);
-    }
-
-    currentSymbol = symbol;
+    const chainId = currentNetwork().chainId;
+    const knownToken = bundledToken(tokenId, chainId);
+    currentSymbol =
+        tokenId === "ETH"
+            ? nativeCurrency()
+            : resolveSymbol(
+                  tokenId,
+                  addr.tokenBalances,
+                  state.trackedTokens,
+                  chainId,
+              );
 
     $("address-token-title").textContent =
         wallet.name +
         " \u2014 Address " +
         (ai + 1) +
         " \u2014 " +
-        displaySymbol(symbol);
+        displaySymbol(currentSymbol);
 
     // Blockie
     const blockieEl = $("address-token-jazzicon");
@@ -101,13 +89,7 @@ function show() {
     $("address-token-line").dataset.full = addr.address;
     attachCopyHandlers($("address-token-line"));
 
-    // 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(symbol, amount, price);
+    renderBalance();
 
     // Token contract details (ERC-20 only)
     const contractInfo = $("address-token-contract-info");
@@ -169,7 +151,49 @@ 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,
+        );
+        const tracked = state.trackedTokens.find(
+            (t) => t.address.toLowerCase() === id,
+        );
+        // null when the scale is unknown, or when no refresh has read the
+        // balance of 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 = tracked && tracked.balanceNotFetched ? null : 0;
+        price = getPrice(tokenId);
+    }
+
+    // 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) {
+    const networkId = state.networkId;
     try {
         const rawTxs = await fetchRecentTransactions(
             address,
@@ -186,16 +210,6 @@ async function loadTransactions(address, tokenId) {
         });
         let txs = result.transactions;
 
-        // Persist any newly discovered fraud contracts
-        if (result.newFraudContracts.length > 0) {
-            for (const addr of result.newFraudContracts) {
-                if (!state.fraudContracts.includes(addr)) {
-                    state.fraudContracts.push(addr);
-                }
-            }
-            await saveState();
-        }
-
         // Filter to this token only
         if (tokenId === "ETH") {
             txs = txs.filter((tx) => tx.contractAddress === null);
@@ -207,32 +221,75 @@ async function loadTransactions(address, tokenId) {
             );
         }
 
-        loadedTxs = txs;
-
         // Collect ALL unique addresses for ENS resolution so reverse
         // lookups work for every displayed address.
         const counterparties = [
             ...new Set(txs.flatMap((tx) => [tx.from, tx.to].filter(Boolean))),
         ];
+        let names = new Map();
         if (counterparties.length > 0) {
             try {
-                ensNameMap = await resolveEnsNames(
+                names = await resolveEnsNames(
                     counterparties,
                     state.rpcUrl,
                     state.networkId,
                     ctx.pageClosed,
                 );
             } catch {
-                ensNameMap = new Map();
+                // The rows then show no ENS names.
             }
         }
 
+        // If the network changed during the lookups above, or the screen now
+        // shows another address or token, nothing is saved or drawn. See
+        // src/shared/storedSettings.js.
+        if (
+            state.networkId !== networkId ||
+            !(await storedNetworkIs(networkId)) ||
+            $("address-token-line").dataset.full !== address ||
+            state.selectedToken !== tokenId
+        ) {
+            return;
+        }
+
+        // Persist any newly discovered fraud contracts, inside the save and
+        // holding the lock. Nothing is added unless this page and the stored
+        // record both still name the request's network.
+        if (result.newFraudContracts.length > 0) {
+            let saved = false;
+            await saveState((stored) => {
+                if (state.networkId !== networkId) return false;
+                if (stored.networkId !== networkId) return false;
+                for (const addr of result.newFraudContracts) {
+                    if (!state.fraudContracts.includes(addr)) {
+                        state.fraudContracts.push(addr);
+                    }
+                }
+                saved = true;
+            });
+            // If the network changed while the save waited for the lock,
+            // nothing is drawn.
+            if (!saved) return;
+        }
+
+        loadedTxs = txs;
+        ensNameMap = names;
         renderTransactions(txs);
     } catch (e) {
         // Cancelled by the popup closing, not failed: see pageClosed in
         // src/popup/index.js.
         if (ctx.pageClosed.aborted) return;
         log.errorf("loadTransactions failed:", e.message);
+        // If the network changed, or the screen now shows another address or
+        // token, the failure is not shown.
+        if (
+            state.networkId !== networkId ||
+            !(await storedNetworkIs(networkId)) ||
+            $("address-token-line").dataset.full !== address ||
+            state.selectedToken !== tokenId
+        ) {
+            return;
+        }
         $("address-token-tx-list").innerHTML =
             '<div class="text-muted text-xs py-1">Failed to load transactions.</div>';
     }
@@ -348,4 +405,4 @@ function init(_ctx) {
     });
 }
 
-module.exports = { init, show };
+module.exports = { init, show, renderBalance };

src/popup/views/helpers.js

@@ -33,6 +33,7 @@ const { networkByChainId } = require("../../shared/networks");
 const { formatUsd, getPrice } = require("../../shared/prices");
 const { state, saveState, currentNetwork } = require("../../shared/state");
 const { displaySymbol } = require("../../shared/symbolDisplay");
+const { isSpoofedSymbol } = require("../../shared/symbolSpoof");
 const { walletHasRecoveryPhrase } = require("../../shared/wallet");
 const { markViewRendered } = require("../viewRouter");
 
@@ -313,14 +314,17 @@ function nativeCurrency() {
 // The wallets' balances hold what Blockscout reported for each token. So the
 // wallets are returned only while "Use Blockscout" is on.
 function tokenSourcesByChainId(chainId) {
-    const net = chainId ? networkByChainId(chainId) : currentNetwork();
+    const chainIdOrActive = chainId || currentNetwork().chainId;
+    const net = networkByChainId(chainIdOrActive);
     if (net && net.id === state.networkId) {
         return {
+            chainId: chainIdOrActive,
             trackedTokens: state.trackedTokens,
             wallets: state.useBlockscout ? state.wallets : [],
         };
     }
     return {
+        chainId: chainIdOrActive,
         trackedTokens: (net && state.networkTrackedTokens[net.id]) || [],
         wallets: [],
     };
@@ -351,7 +355,7 @@ function blockscoutOffTokenNoteHtml(token, chainId) {
 
 // The symbol shown for a token line, from these sources in order:
 //
-// - the bundled list
+// - the bundled list, for a token on Ethereum Mainnet
 // - the tokens the user tracks
 // - the explorer's report, while "Use Blockscout" is on
 //
@@ -417,6 +421,15 @@ function balanceLine(symbol, amount, price, tokenId) {
     );
 }
 
+// Tracks `token` on the active network, as every add path on AddToken and
+// SettingsAddToken does. The tracked record carries `balanceNotFetched: true`
+// until a balance refresh has read the token's balance at every address
+// (doRefreshAndRender() in src/popup/index.js). Until then, an address with no
+// balance row for the token shows `quantity unknown` for it, not 0.0000.
+function trackToken(token) {
+    state.trackedTokens.push({ ...token, balanceNotFetched: true });
+}
+
 function balanceLinesForAddress(addr, trackedTokens, showZero) {
     let html = balanceLine(
         nativeCurrency(),
@@ -447,9 +460,16 @@ function balanceLinesForAddress(addr, trackedTokens, showZero) {
     if (showZero && trackedTokens) {
         for (const t of trackedTokens) {
             if (seen.has(t.address.toLowerCase())) continue;
+            // A token that the spoof rule refuses has no stored balance, and
+            // gets no zero row either.
+            if (
+                isSpoofedSymbol(t.symbol, t.address, currentNetwork().chainId)
+            ) {
+                continue;
+            }
             html += balanceLine(
                 t.symbol,
-                0,
+                t.balanceNotFetched ? null : 0,
                 getPrice(t.address),
                 t.address.toLowerCase(),
             );
@@ -829,6 +849,7 @@ module.exports = {
     flashCopyFeedback,
     balanceLine,
     balanceLinesForAddress,
+    trackToken,
     addressHoldsFunds,
     keyMaterialName,
     unknownableAmount,

src/popup/views/home.js

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

src/popup/views/send.js

@@ -12,7 +12,7 @@ const {
     goBack,
     tokenSourcesByChainId,
 } = require("./helpers");
-const { state, currentAddress } = require("../../shared/state");
+const { state, currentAddress, currentNetwork } = require("../../shared/state");
 let ctx;
 const { getProvider } = require("../../shared/balances");
 const { resolveTokenDecimals } = require("../../shared/approvalAmount");
@@ -154,7 +154,9 @@ function renderSendTokenSelect(addr) {
         // out. Its token's own screen can still send it: there
         // state.selectedToken picks the token, not this list.
         if (isBelowOneMillionth(t.balance)) continue;
-        if (isSpoofedSymbol(t.symbol, t.address)) continue;
+        if (isSpoofedSymbol(t.symbol, t.address, currentNetwork().chainId)) {
+            continue;
+        }
         if (fraudSet.has(t.address.toLowerCase())) continue;
         // An unknown holder count does not withhold a token the user holds:
         // only a count the explorer actually reported as below the threshold
@@ -198,13 +200,21 @@ function renderSendTokenSelect(addr) {
 // null rather than "0": this screen states it as unknown, as the confirmation
 // screen does, and Max fills nothing in for it. Only a stored quantity is
 // withdrawn: the "0" for a token that has no row at all is an absence of
-// holdings, which is true at every scale.
+// holdings, which is true at every scale. A token with no row whose tracked
+// record carries `balanceNotFetched` gets null instead, because no refresh has
+// read its balance.
 function tokenBalanceAndDecimals(addr, token) {
     const tb = (addr.tokenBalances || []).find(
         (t) => t.address.toLowerCase() === token.toLowerCase(),
     );
     const tokenDecimals = resolveTokenDecimals(token, tokenSourcesByChainId());
-    if (!tb) return { tokenBalance: "0", tokenDecimals };
+    if (!tb) {
+        const tracked = state.trackedTokens.find(
+            (t) => t.address.toLowerCase() === token.toLowerCase(),
+        );
+        const notRead = tracked && tracked.balanceNotFetched;
+        return { tokenBalance: notRead ? null : "0", tokenDecimals };
+    }
     if (tokenDecimals === null) return { tokenBalance: null, tokenDecimals };
     return { tokenBalance: tb.balance ?? null, tokenDecimals };
 }
@@ -230,6 +240,7 @@ function updateSendBalance() {
             token,
             addr.tokenBalances,
             state.trackedTokens,
+            currentNetwork().chainId,
         );
         // A null balance is a holding whose scale is unknown. Saying a figure
         // for it would be a claim about the amount, so it reads as the
@@ -385,6 +396,7 @@ function init(_ctx) {
                 token,
                 addr.tokenBalances,
                 state.trackedTokens,
+                currentNetwork().chainId,
             );
             ({ tokenDecimals } = tokenBalanceAndDecimals(addr, token));
         }

src/popup/views/settings.js

@@ -44,6 +44,17 @@ let ctx;
 let versionClickCount = 0;
 let versionClickTimer = null;
 
+// The network that Settings was last drawn for. A follow of a switch saved
+// elsewhere sets `state` to the new network first. Settings is drawn again only
+// once the follow's write returns. So both "Save" buttons take this network,
+// not the one in `state`.
+let shownNetwork = null;
+
+// Each endpoint "Save" counts its taps here, under the field that it stores.
+// Once the user taps the same "Save" again, the earlier tap shows no flash
+// message. The earlier tap stores its URL only if its write had already begun.
+const saveTaps = { rpcUrl: 0, blockscoutUrl: 0 };
+
 // One row per site origin, however many addresses it appears under, each with
 // an [x] that hands it to onRemove.
 function renderSiteList(containerId, origins, onRemove) {
@@ -199,6 +210,7 @@ function renderWalletListSettings() {
 }
 
 function show() {
+    shownNetwork = currentNetwork();
     $("settings-rpc").value = state.rpcUrl;
     $("settings-blockscout").value = state.blockscoutUrl;
     $("settings-network").value = state.networkId;
@@ -306,6 +318,7 @@ function showNewSettings() {
         state.checkRecipientsOnEtherscan;
     if (state.currentView === "settings") {
         markViewRendered("settings");
+        shownNetwork = currentNetwork();
         $("settings-network").value = state.networkId;
         $("settings-rpc").value = state.rpcUrl;
         $("settings-blockscout").value = state.blockscoutUrl;
@@ -319,17 +332,70 @@ function showNewSettings() {
     updateDebugBanner(state.currentView);
 }
 
+// Saves `url` as `field` ("rpcUrl" or "blockscoutUrl") of the network
+// `networkId`, the one that Settings showed when the user tapped "Save". The
+// URL is set in `state` inside the save, holding the lock. So the page cannot
+// follow a switch saved elsewhere (followStoredSettings() in
+// src/popup/index.js) between setting the URL and writing it. If the active
+// network is no longer `networkId`, on this page or in the stored record,
+// nothing is saved. The flash message then says that the network changed.
+//
+// The save writes only the fields that differ from what this page last saved.
+// Another page may have stored a different URL since then. So `url` is set in
+// the stored record too. "Saved." then means that the stored record holds
+// `url`.
+//
+// `input` is the id of the input that the user typed `url` in. When another
+// page changes the network, "Use Blockscout" or "Check recipients on
+// Etherscan", this page draws Settings again. A redraw during the endpoint
+// check puts the URL from `state` back in the input. So if the input no longer
+// shows `url`, nothing is saved. The flash message then says that the URL was
+// changed during the check. The save compares the input and sets `url` in
+// `state` in one step. So a redraw after the comparison shows `url`.
+//
+// `tap` is the number of the "Save" tap that checked `url`. If the user taps
+// the same "Save" again before this save holds the lock, nothing is stored. If
+// the user taps the same "Save" again before the write ends, no flash message
+// is shown.
+async function saveEndpoint(field, input, url, networkId, tap) {
+    let refused = false;
+    let inputChanged = false;
+    await saveState((stored) => {
+        if (saveTaps[field] !== tap) return false;
+        refused =
+            state.networkId !== networkId || stored.networkId !== networkId;
+        inputChanged = $(input).value.trim() !== url;
+        if (refused || inputChanged) return false;
+        state[field] = url;
+        stored[field] = url;
+    });
+    if (saveTaps[field] !== tap) return;
+    if (refused) {
+        showFlash("The URL was not saved because the network changed.");
+    } else if (inputChanged) {
+        showFlash(
+            "The URL was not saved because it was changed during the check.",
+        );
+    } else {
+        showFlash("Saved.");
+    }
+}
+
 function init(_ctx) {
     ctx = _ctx;
     deleteWallet.init(ctx);
     showPhrase.init();
 
     $("btn-save-rpc").addEventListener("click", async () => {
+        saveTaps.rpcUrl++;
+        const tap = saveTaps.rpcUrl;
         const url = $("settings-rpc").value.trim();
         if (!url) {
             showFlash("Please enter an RPC URL.");
             return;
         }
+        // The URL is for the network that Settings shows when "Save" is tapped.
+        const net = shownNetwork;
         showFlash("Testing endpoint...");
         try {
             const resp = await debugFetch(url, {
@@ -343,12 +409,13 @@ function init(_ctx) {
                 }),
             });
             const json = await resp.json();
+            // The user has tapped this "Save" again since the check began.
+            if (tap !== saveTaps.rpcUrl) return;
             if (json.error) {
                 log.errorf("RPC validation error:", json.error);
                 showFlash("Endpoint returned an error.");
                 return;
             }
-            const net = currentNetwork();
             if (json.result !== net.chainId) {
                 showFlash("Wrong network: expected " + net.name + ".");
                 return;
@@ -357,6 +424,7 @@ function init(_ctx) {
             // Cancelled by the popup closing, not failed: see pageClosed in
             // src/popup/index.js.
             if (ctx.pageClosed.aborted) return;
+            if (tap !== saveTaps.rpcUrl) return;
             // Not the error's message: fetch puts the whole URL, password and
             // key included, in the message of the error it throws for a URL
             // with a user name and password or one it cannot parse.
@@ -364,34 +432,41 @@ function init(_ctx) {
             showFlash("Could not reach endpoint.");
             return;
         }
-        state.rpcUrl = url;
-        await saveState();
-        showFlash("Saved.");
+        await saveEndpoint("rpcUrl", "settings-rpc", url, net.id, tap);
     });
 
     $("btn-save-blockscout").addEventListener("click", async () => {
+        saveTaps.blockscoutUrl++;
+        const tap = saveTaps.blockscoutUrl;
         const url = $("settings-blockscout").value.trim();
         if (!url) {
             showFlash("Please enter a Blockscout API URL.");
             return;
         }
+        const net = shownNetwork;
         showFlash("Testing endpoint...");
         try {
             const resp = await debugFetch(url + "/stats");
+            if (tap !== saveTaps.blockscoutUrl) return;
             if (!resp.ok) {
                 showFlash("Endpoint returned HTTP " + resp.status + ".");
                 return;
             }
         } catch {
             if (ctx.pageClosed.aborted) return;
+            if (tap !== saveTaps.blockscoutUrl) return;
             // Not the error's message, as for the RPC check above.
             log.errorf("Blockscout validation failed:", urlOrigin(url));
             showFlash("Could not reach endpoint.");
             return;
         }
-        state.blockscoutUrl = url;
-        await saveState();
-        showFlash("Saved.");
+        await saveEndpoint(
+            "blockscoutUrl",
+            "settings-blockscout",
+            url,
+            net.id,
+            tap,
+        );
     });
 
     // Each change is made inside the save, holding the lock. So

src/popup/views/settingsAddToken.js

@@ -1,8 +1,16 @@
-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");
 const { isScamAddress } = require("../../shared/scamlist");
+const { isSpoofedSymbol } = require("../../shared/symbolSpoof");
 const { log } = require("../../shared/log");
 
 let ctx;
@@ -43,7 +51,7 @@ 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 +118,7 @@ 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();
@@ -155,8 +163,18 @@ function init(_ctx) {
                 );
                 return;
             }
+            // The balance list never shows a token that the spoof rule
+            // refuses, so such a token is not tracked. The rule never refuses
+            // a bundled token, so the "Top tokens:" buttons and the top 100
+            // dropdown need no such check.
+            if (isSpoofedSymbol(info.symbol, addr, chainId)) {
+                showFlash("Not added: this token fakes a known symbol.");
+                infoEl.textContent = "";
+                infoEl.style.visibility = "hidden";
+                return;
+            }
             log.infof("Adding token", info.symbol, addr);
-            state.trackedTokens.push({
+            trackToken({
                 address: addr,
                 symbol: info.symbol,
                 decimals: info.decimals,

src/popup/views/transactionDetail.js

@@ -311,10 +311,21 @@ function populateOnChainDetails(txData, chainId) {
     }
 }
 
+// Whether TransactionDetail still holds the transaction with `txHash` on
+// `chainId`. Opening another transaction replaces the one TransactionDetail
+// holds. A visit to Settings does not.
+function holdsTransaction(txHash, chainId) {
+    const tx = state.viewData.tx;
+    return tx?.hash === txHash && tx?.chainId === chainId;
+}
+
 // Reads the block, network details and calldata from Blockscout, and decodes
 // the calldata. While the stored "Use Blockscout" is off, Blockscout is not
 // asked. An answer that lands after the setting went off is dropped
 // (src/shared/storedSettings.js). Either way none of them is shown.
+//
+// Blockscout can answer after the user has opened another transaction. That
+// answer is dropped.
 async function loadFullTxDetails(txHash, chainId) {
     if (!(await storedSettingIsOn("useBlockscout"))) return;
     const section = $("tx-detail-calldata-section");
@@ -333,6 +344,7 @@ async function loadFullTxDetails(txHash, chainId) {
         if (!resp.ok) return;
         const txData = await resp.json();
         if (!(await storedSettingIsOn("useBlockscout"))) return;
+        if (!holdsTransaction(txHash, chainId)) return;
 
         // Populate on-chain detail fields (block, nonce, gas, fee)
         populateOnChainDetails(txData, chainId);

src/shared/approvalAmount.js

@@ -29,7 +29,7 @@
 // string, and a token the user added by hand carries whatever lookupTokenInfo()
 // got back, so the accepted types are enumerated rather than coerced.
 const { toDecimals } = require("./transferAmount");
-const { TOKEN_BY_ADDRESS } = require("./tokenList");
+const { bundledToken } = require("./tokenList");
 const { isSpoofedSymbol } = require("./symbolSpoof");
 
 // Every decimals the explorer reported for this contract, across all the
@@ -53,12 +53,14 @@ function explorerDecimals(lower, wallets) {
 }
 
 // The decimals to render a token amount with, or null when nothing knows.
-// `sources` is { trackedTokens, wallets }, both shaped as they are on `state`.
+// `sources` is { chainId, trackedTokens, wallets }. `chainId` is the chain id
+// of the token's network. The bundled list is read only when that network is
+// Ethereum Mainnet. `trackedTokens` and `wallets` are shaped as on `state`.
 function resolveTokenDecimals(tokenAddress, sources) {
     const lower = (tokenAddress || "").toLowerCase();
     if (!lower) return null;
 
-    const bundled = TOKEN_BY_ADDRESS.get(lower);
+    const bundled = bundledToken(lower, sources && sources.chainId);
     if (bundled) {
         const d = toDecimals(bundled.decimals);
         if (d !== null) return d;
@@ -100,18 +102,19 @@ function explorerSymbol(lower, wallets) {
 // explorer reported: the same sources and the same precedence
 // resolveTokenDecimals() uses, so a token's name and its scale are drawn from
 // the same place and the two can no longer disagree about which sources they
-// trust. `sources` is { trackedTokens, wallets }, shaped as on `state`.
+// trust. `sources` is as for resolveTokenDecimals().
 //
 // A tracked or explorer-reported symbol is attacker-influenced text, so it is
-// held to the spoof rule (symbolSpoof.js): a candidate that wears a bundled or
-// native ticker from a contract not entitled to it is refused and the next
-// source tried, so resolving a symbol never becomes a new way to claim a known
-// ticker. The bundled list is the wallet's own data and is trusted as it is.
+// held to the spoof rule (symbolSpoof.js): a candidate that the rule calls a
+// spoof is refused and the next source tried, so resolving a symbol never
+// becomes a new way to claim a known ticker. The bundled list is the wallet's
+// own data and is trusted as it is.
 function resolveTokenSymbol(tokenAddress, sources) {
     const lower = (tokenAddress || "").toLowerCase();
     if (!lower) return null;
 
-    const bundled = TOKEN_BY_ADDRESS.get(lower);
+    const chainId = sources && sources.chainId;
+    const bundled = bundledToken(lower, chainId);
     if (bundled && bundled.symbol) return bundled.symbol;
 
     const tracked = ((sources && sources.trackedTokens) || []).find(
@@ -123,7 +126,7 @@ function resolveTokenSymbol(tokenAddress, sources) {
     if (reported) candidates.push(reported);
 
     for (const symbol of candidates) {
-        if (!isSpoofedSymbol(symbol, tokenAddress)) return symbol;
+        if (!isSpoofedSymbol(symbol, tokenAddress, chainId)) return symbol;
     }
     return null;
 }

src/shared/balances.js

@@ -17,7 +17,7 @@ const { ERC20_ABI } = require("./constants");
 const { NETWORKS } = require("./networks");
 const { log, debugFetch, urlOrigin } = require("./log");
 const { deriveAddressFromXpub } = require("./wallet");
-const { TOKEN_BY_ADDRESS } = require("./tokenList");
+const { bundledToken } = require("./tokenList");
 const { LOW_HOLDER_THRESHOLD, parseHoldersCount } = require("./holders");
 const { isSpoofedSymbol } = require("./symbolSpoof");
 const { toDecimals } = require("./transferAmount");
@@ -106,6 +106,9 @@ function rawUnits(value) {
 // balance is read through the RPC endpoint instead, and its row here gives that
 // entry its holder count and `decimals` (fetchTrackedTokenBalances()).
 //
+// `chainId` is the chain id of the network `blockscoutUrl` serves. The known
+// token list is used only when that network is Ethereum Mainnet.
+//
 // `decimals` and `balance` are each null when the answer is unknown, the same
 // way `holders` already is. Absence is never filled in here: this is the
 // upstream of every screen that displays a token amount, so a value invented
@@ -117,6 +120,7 @@ async function fetchTokenBalances(
     address,
     blockscoutUrl,
     trackedTokens,
+    chainId,
     signal,
 ) {
     if (!(await storedSettingIsOn("useBlockscout"))) return [];
@@ -175,7 +179,10 @@ async function fetchTokenBalances(
             // either way: copying another source into it would make
             // explorerDecimals()'s disagreement check compare something other
             // than explorer values.
-            const known = resolveTokenDecimals(tokenAddr, { trackedTokens });
+            const known = resolveTokenDecimals(tokenAddr, {
+                chainId,
+                trackedTokens,
+            });
             const scale = known !== null ? known : decimals;
             // null is a holding of an amount that cannot be stated, which is
             // not the same as a holding of zero, and must never render as one.
@@ -191,7 +198,7 @@ async function fetchTokenBalances(
             // through to the views, where the two low-holder filters treat
             // an unknown count as "do not judge" rather than as zero.
             const holders = parseHoldersCount(item.token.holders_count);
-            const isKnown = TOKEN_BY_ADDRESS.has(tokenAddr);
+            const isKnown = bundledToken(tokenAddr, chainId) !== null;
             const isTracked = trackedSet.has(tokenAddr);
             const hasEnoughHolders = holders >= LOW_HOLDER_THRESHOLD;
 
@@ -202,7 +209,9 @@ async function fetchTokenBalances(
             // Every row here is an ERC-20 the explorer reported, so it has a
             // contract address; the native ETH balance is fetched over RPC in
             // refreshBalances and never passes through this loop.
-            if (isSpoofedSymbol(item.token.symbol, tokenAddr)) continue;
+            if (isSpoofedSymbol(item.token.symbol, tokenAddr, chainId)) {
+                continue;
+            }
 
             balances.push({
                 address: item.token.address_hash,
@@ -247,19 +256,24 @@ async function fetchTokenBalances(
 // it has none. The failure is logged. A balance of zero gets no entry, as a
 // zero Blockscout reports gets none: the balance lists take a tracked token's
 // zero from the tracked list. A token whose symbol the spoof rule refuses gets
-// no entry either, as in fetchTokenBalances().
+// no entry either, as in fetchTokenBalances(), and its balance is not read.
 //
-// `signal` is as for fetchTokenBalances().
+// Resolves with `rows`, the entries, and `unread`, the tracked tokens whose
+// balance was not read, as lowercased contract addresses. A token is unread
+// when the spoof rule refuses it or its balanceOf fails.
+//
+// `chainId` and `signal` are as for fetchTokenBalances().
 async function fetchTrackedTokenBalances(
     provider,
     address,
     trackedTokens,
     previous,
     explorerRequest,
+    chainId,
     signal,
 ) {
     const listed = trackedTokens.filter(
-        (token) => !isSpoofedSymbol(token.symbol, token.address),
+        (token) => !isSpoofedSymbol(token.symbol, token.address, chainId),
     );
     // Each token's balanceOf answer, or null where it failed.
     const balances = await Promise.all(
@@ -288,12 +302,16 @@ async function fetchTrackedTokenBalances(
     const reported = explorerRows ?? previous;
 
     const rows = [];
+    const unread = trackedTokens
+        .filter((token) => !listed.includes(token))
+        .map((token) => token.address.toLowerCase());
     listed.forEach((token, i) => {
         const lower = token.address.toLowerCase();
         const entryIn = (list) =>
             list.find((row) => String(row.address).toLowerCase() === lower);
         const raw = balances[i];
         if (raw === null) {
+            unread.push(lower);
             const kept = entryIn(previous) || entryIn(explorerRows || []);
             if (kept) rows.push(kept);
             return;
@@ -301,7 +319,7 @@ async function fetchTrackedTokenBalances(
         if (raw === 0n) return;
         const entry = entryIn(reported);
         const decimals = entry ? entry.decimals : null;
-        const known = resolveTokenDecimals(lower, { trackedTokens });
+        const known = resolveTokenDecimals(lower, { chainId, trackedTokens });
         const scale = known !== null ? known : decimals;
         rows.push({
             address: token.address,
@@ -314,12 +332,15 @@ async function fetchTrackedTokenBalances(
             holders: entry ? entry.holders : null,
         });
     });
-    return rows;
+    return { rows, unread };
 }
 
 // Fetch ETH balances, ENS names, and ERC-20 token balances for all addresses.
 // `trackedTokens` are the tokens tracked on the active network. `signal` is as
 // for fetchTokenBalances().
+//
+// Resolves with the lowercased contract addresses of the tracked tokens whose
+// balance it read at every address.
 async function refreshBalances(
     wallets,
     rpcUrl,
@@ -330,8 +351,11 @@ async function refreshBalances(
 ) {
     log.debugf("refreshBalances start, rpc:", urlOrigin(rpcUrl));
     const provider = getProvider(rpcUrl, networkId);
+    const { chainId } = requireNetworkId(networkId);
     const tracked = trackedTokens || [];
     const trackedSet = new Set(tracked.map((t) => t.address.toLowerCase()));
+    // The tracked tokens whose balance was not read at some address.
+    const unread = new Set();
     const updates = [];
 
     for (const wallet of wallets) {
@@ -393,6 +417,7 @@ async function refreshBalances(
                 addr.address,
                 blockscoutUrl,
                 tracked,
+                chainId,
                 signal,
             );
             updates.push(
@@ -403,15 +428,18 @@ async function refreshBalances(
                         tracked,
                         previous,
                         explorerRequest,
+                        chainId,
                         signal,
                     ),
                     explorerRequest,
-                ]).then(([trackedRows, explorerRows]) => {
+                ]).then(([trackedResult, explorerRows]) => {
+                    for (const lower of trackedResult.unread) unread.add(lower);
                     const untrackedRows = (explorerRows ?? previous).filter(
                         (row) =>
                             !trackedSet.has(String(row.address).toLowerCase()),
                     );
-                    addr.tokenBalances = trackedRows.concat(untrackedRows);
+                    addr.tokenBalances =
+                        trackedResult.rows.concat(untrackedRows);
                     log.debugf(
                         "Token balances",
                         addr.address,
@@ -425,6 +453,7 @@ async function refreshBalances(
 
     await Promise.all(updates);
     log.debugf("refreshBalances done");
+    return [...trackedSet].filter((lower) => !unread.has(lower));
 }
 
 // Drops the balance of each token not in `trackedTokens` from every address.

src/shared/chainSwitch.js

@@ -47,12 +47,63 @@ function clearPopupCaches() {
 // lock, so it is never switched while a follow of a switch saved elsewhere
 // waits for the lock (followStoredSettings() in src/popup/index.js): that
 // follow runs first, and this switch is made after it.
+//
+// The save writes only the fields that differ from what this page last saved.
+// When this page last saved a balance of "0", clearing that balance is no
+// change. So the switch also resets these fields in the stored record:
+//
+// - every address's balance and token balances;
+// - the time of the last balance refresh;
+// - the fraud contracts.
+//
+// A balance or a fraud contract that the background or another page stored
+// since this page's last save is then not kept under the new network
+// (https://git.eeqj.de/sneak/AutistMask/issues/653,
+// https://git.eeqj.de/sneak/AutistMask/issues/692).
+//
+// When the stored record is on another network, a switch saved elsewhere has
+// not reached this page yet. This page first takes that switch with
+// takeStoredNetwork() (state.js), as followStoredSettings() does. The switch to
+// `newNetworkId` is then made from the stored record's network. So every
+// network's list of tracked tokens in the stored record is kept
+// (https://git.eeqj.de/sneak/AutistMask/issues/701). When the stored record is
+// already on `newNetworkId`, the switch made from there only resets the
+// balances and caches.
+//
+// When the stored record is on this page's network, this page first takes the
+// stored `networkTrackedTokens` (takeStoredNetworkTrackedTokens() in state.js),
+// because another page's save may have changed a list this page holds.
+//
+// Before the switch, `state` takes the tracked tokens that another page stored
+// since this page's last save (takeStoredTrackedTokens() in state.js). The
+// switch then puts them away under the previous network, the network they were
+// added on.
 async function onChainSwitch(newNetworkId) {
-    const { state, saveState } = require("./state");
+    const {
+        state,
+        saveState,
+        takeStoredNetwork,
+        takeStoredTrackedTokens,
+        takeStoredNetworkTrackedTokens,
+    } = require("./state");
     let net = null;
-    await saveState(() => {
+    await saveState((stored) => {
         if (state.networkId === newNetworkId) return false;
+        if (stored.networkId !== state.networkId) {
+            takeStoredNetwork(stored);
+        } else {
+            takeStoredNetworkTrackedTokens(stored);
+        }
+        takeStoredTrackedTokens(stored);
         net = applyChainSwitchFields(state, newNetworkId);
+        stored.lastBalanceRefresh = 0;
+        stored.fraudContracts = [];
+        for (const wallet of stored.wallets) {
+            for (const addr of wallet.addresses) {
+                addr.balance = "0";
+                addr.tokenBalances = [];
+            }
+        }
         clearPopupCaches();
     });
     return net;

src/shared/prices.js

@@ -28,7 +28,8 @@ let lastFetchedAt = 0;
 // logged, and that token then has no price.
 //
 // `signal`, passed by the popup, is aborted when the popup closes. A read that
-// fails after that was cancelled by the closing and is not logged.
+// fails once `signal` is aborted is not logged, because closing the popup
+// cancelled it.
 async function refreshPrices(signal) {
     const { state, currentNetwork } = require("./state");
     if (currentNetwork().id !== "mainnet") {

src/shared/state.js

@@ -125,11 +125,14 @@ function currentNetwork() {
     return networkById(state.networkId);
 }
 
-// The persisted fields as this page held them when its last loadState()
-// finished, or when its last successful saveState() began, with any network
-// 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.
+// `baseline` holds the persisted fields as this page held them when its last
+// loadState() finished, or when its last successful saveState() began.
+// takeStoredNetwork(), takeStoredTrackedTokens() and
+// takeStoredNetworkTrackedTokens() also write into it what this page has taken
+// from the stored record since then. `baseline` also lacks any
+// `balanceNotFetched` field that a balance refresh has deleted since
+// (clearBalanceNotFetched()). saveState() diffs the live state against
+// `baseline` 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
@@ -401,6 +404,23 @@ function mergeNetworkEndpoints(base, ours, theirs) {
     return mergeMapByKey(base, ours, theirs, mergeEndpointEntry);
 }
 
+// Returns a copy of `stored.networkTrackedTokens` for when this page has not yet
+// taken the switch in `stored`. `page` is this page's state. A token that this
+// page tracked or removed since its last save is tracked or removed in the list
+// of `page.networkId`, by contract address.
+function networkTrackedTokensWithChange(stored, page) {
+    return {
+        ...stored.networkTrackedTokens,
+        [page.networkId]: mergeListByIdentity(
+            baseline.trackedTokens,
+            page.trackedTokens,
+            stored.networkTrackedTokens[page.networkId],
+            (token) => token.address.toLowerCase(),
+            (base, ours) => ours,
+        ),
+    };
+}
+
 // Read-modify-write, merged per field, rather than one full-blob write.
 //
 // Every extension page (the toolbar popup, a dApp approval window) holds its
@@ -442,8 +462,10 @@ function mergeNetworkEndpoints(base, ours, theirs) {
 // milder than the other two.
 //
 // Every other persisted field stays a whole-field diff:
-// `trackedTokens`/`fraudContracts`/`viewStack` are arrays of scalars with no
-// per-element identity to merge by; `networkTrackedTokens` is diffed whole like
+// `fraudContracts`/`viewStack` are arrays of scalars with no per-element
+// identity to merge by; a save diffs `trackedTokens` whole, and a switch in
+// Settings first merges that list by contract address
+// (takeStoredTrackedTokens()); `networkTrackedTokens` is diffed whole like
 // `trackedTokens` and `networkId`, the two fields a network switch moves
 // together with it; `tokenHolderCache` is a map shaped like the ones above,
 // but nothing in src/ ever writes an entry into it — it is only ever reset
@@ -452,6 +474,11 @@ function mergeNetworkEndpoints(base, ours, theirs) {
 // own UI scratch space, not data another page has any reason to share
 // membership of.
 //
+// One exception: when the stored record is on another network than this
+// page's, a save keeps the stored `trackedTokens`. It merges this page's change
+// into the list in `networkTrackedTokens` for this page's network, by contract
+// address.
+//
 // This does not make two pages that both change the SAME leaf concurrently
 // safe: last write wins on that one leaf, same as before. What it removes
 // is the cross-field (and now cross-membership-vs-leaf) clobber — a page
@@ -524,6 +551,20 @@ async function saveStateOnce(beforeWrite) {
             merged[key] = current[key];
         }
     }
+    // When the merged record names a network other than this page's, this page
+    // has not yet taken a switch saved elsewhere. This page's `trackedTokens`
+    // is then the list of this page's network. The stored record keeps the
+    // list of this page's network in `networkTrackedTokens`. So a token that
+    // this page added or removed since its last save is added to or removed
+    // from that stored list. The merged record keeps the stored `trackedTokens`
+    // (https://git.eeqj.de/sneak/AutistMask/issues/701).
+    if (merged.networkId !== current.networkId) {
+        merged.trackedTokens = fresh.trackedTokens;
+        merged.networkTrackedTokens = networkTrackedTokensWithChange(
+            fresh,
+            current,
+        );
+    }
     merged.hasWallet = Boolean(merged.wallets && merged.wallets.length > 0);
     // Stamped on every write, never merged or diffed: the record that goes to
     // storage is in THIS build's shape whatever shape it was read in, which is
@@ -591,8 +632,10 @@ function reportSaveFailure(err) {
 //
 // `beforeWrite`, when given, is called inside the lock with the stored record
 // as just read, before this page's state is compared against it. It may change
-// `state`, and this save writes that change. When it returns false, nothing is
-// written; any other return lets the save go ahead.
+// `state`, and this save writes that change. It may also change the stored
+// record. A field that this page did not change is then written as
+// `beforeWrite` left it. 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
@@ -602,15 +645,83 @@ function saveState(beforeWrite) {
     return turn;
 }
 
-// Give this page the network switch held by `stored`, a record a save of this
-// page has just read (followStoredSettings() 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
+// Give this page the network switch held by `stored`, in `state` and in
+// `baseline` alike, as loadState() does with a whole record. `stored` is the
+// record that a save of this page has just read. followStoredSettings() in
+// src/popup/index.js and onChainSwitch() in src/shared/chainSwitch.js call this
+// from `beforeWrite`. 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.
+//
+// A token that this page tracked or removed since its last save was tracked or
+// removed on this page's network before the switch. `state` keeps that change
+// in the list in `networkTrackedTokens` for that network, merged with the
+// stored list by contract address. `baseline` takes the stored list, so the
+// save stores the change (https://git.eeqj.de/sneak/AutistMask/issues/706).
 function takeStoredNetwork(stored) {
+    const networkTrackedTokens = networkTrackedTokensWithChange(
+        stored,
+        rawState,
+    );
     copyChainSwitchFields(rawState, stored);
     copyChainSwitchFields(baseline, structuredClone(stored));
+    rawState.networkTrackedTokens = networkTrackedTokens;
+}
+
+// Give this page the tracked tokens of `stored`, a record on this page's
+// network that a save of this page has just read (onChainSwitch() in
+// src/shared/chainSwitch.js calls this from `beforeWrite`):
+//
+// - A token that another page tracked or removed since this page's last save
+//   is tracked or removed in `state` too.
+// - A token that this page tracked or removed since then stays as this page
+//   has it.
+//
+// `baseline` takes the stored list, so the save stores the list in `state`
+// whenever the two differ.
+function takeStoredTrackedTokens(stored) {
+    rawState.trackedTokens = mergeListByIdentity(
+        baseline.trackedTokens,
+        rawState.trackedTokens,
+        stored.trackedTokens,
+        (token) => token.address.toLowerCase(),
+        (base, ours) => ours,
+    );
+    baseline.trackedTokens = structuredClone(stored.trackedTokens);
+}
+
+// Give `state` and `baseline` each their own copy of the stored
+// `networkTrackedTokens`. `stored` is a record on this page's network that a
+// save of this page has just read. onChainSwitch() in
+// src/shared/chainSwitch.js calls this from `beforeWrite`.
+function takeStoredNetworkTrackedTokens(stored) {
+    rawState.networkTrackedTokens = structuredClone(
+        stored.networkTrackedTokens,
+    );
+    baseline.networkTrackedTokens = structuredClone(
+        stored.networkTrackedTokens,
+    );
+}
+
+// Deletes `balanceNotFetched` from each tracked token whose lowercased
+// contract address is in `addresses`. The field goes from `stored`, from
+// `state` and from `baseline` alike. `stored` is the record a save of this
+// page has just read (doRefreshAndRender() in src/popup/index.js calls this
+// from `beforeWrite`). So the deletion is not a change this page made to its
+// tracked tokens. Unless this page has changed its tracked tokens itself, the
+// save then writes the stored list with only the field gone.
+function clearBalanceNotFetched(stored, addresses) {
+    for (const list of [
+        stored.trackedTokens,
+        rawState.trackedTokens,
+        baseline.trackedTokens,
+    ]) {
+        for (const token of list) {
+            if (addresses.includes(token.address.toLowerCase())) {
+                delete token.balanceNotFetched;
+            }
+        }
+    }
 }
 
 // Rejects with StateUnusableError for a stored record this build cannot make
@@ -659,6 +770,9 @@ module.exports = {
     saveState,
     onSaveFailure,
     takeStoredNetwork,
+    takeStoredTrackedTokens,
+    takeStoredNetworkTrackedTokens,
+    clearBalanceNotFetched,
     loadState,
     currentAddress,
     currentNetwork,

src/shared/storedSettings.js

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

src/shared/symbolSpoof.js

@@ -19,7 +19,8 @@
 // them hid the other one's holders' money (issue #276).  Membership, not
 // equality, is therefore the question — but it is the same question, asked of
 // a table that can now state the truth.  Every address in a set is one the
-// wallet ships as a real token; a contract outside the set is still a spoof.
+// wallet ships as a real token on Ethereum Mainnet.  On mainnet, a contract
+// outside the set is still a spoof.
 //
 // The symbol is attacker-controlled — it is whatever the ERC-20 contract
 // returns — so the lookup is done on a normalized form (issue #260): the
@@ -27,6 +28,7 @@
 // since that is what the user acts on.
 
 const { KNOWN_SYMBOLS } = require("./tokenList");
+const { NETWORKS } = require("./networks");
 
 // Ethereum addresses are case-insensitive: EIP-55 mixed case is a checksum
 // over the address, not part of its identity.
@@ -93,18 +95,24 @@ function normalizeSymbol(symbol) {
 }
 
 // True when a token bearing `symbol` from contract `contractAddress` is
-// impersonating a known symbol.
+// impersonating a known symbol. `chainId` is the chain id of the token's
+// network.
+//
+// The native asset's labels are known symbols on every network. The bundled
+// list's symbols are known symbols only on Ethereum Mainnet, because the list
+// holds mainnet contracts.
 //
 // An empty contract address is the native asset, which is never a spoof:
 // this is what keeps the user's real ETH out of the rule, and it holds for
 // any symbol that becomes null-mapped later, not just for ETH.
-function isSpoofedSymbol(symbol, contractAddress) {
+function isSpoofedSymbol(symbol, contractAddress, chainId) {
     const contract = normalizeAddress(contractAddress);
     if (!contract) return false;
     const sym = normalizeSymbol(symbol);
     if (!KNOWN_SYMBOLS.has(sym)) return false;
     const legit = KNOWN_SYMBOLS.get(sym);
     if (legit === null) return true;
+    if (chainId !== NETWORKS.mainnet.chainId) return false;
     return !legit.has(contract);
 }
 

src/shared/tokenList.js

@@ -3953,6 +3953,15 @@ for (const t of TOKENS) {
     TOKEN_BY_ADDRESS.set(t.address.toLowerCase(), t);
 }
 
+// The bundled list's entry for the contract at `address` on the network with
+// chain id `chainId`, or null. The list holds Ethereum Mainnet contracts only.
+// A contract at the same address on another network is another token, so any
+// other chain id gets null.
+function bundledToken(address, chainId) {
+    if (chainId !== NETWORKS.mainnet.chainId) return null;
+    return TOKEN_BY_ADDRESS.get((address || "").toLowerCase()) || null;
+}
+
 // Build a map of symbol (uppercased) -> the set of contract addresses
 // (lowercased) that legitimately bear it.  Used for spoofed-symbol detection.
 // "ETH" maps to null: the native asset has no contract, so no contract may
@@ -3969,7 +3978,8 @@ for (const t of TOKENS) {
 // hides from the balance list, the history and the send selector at its own
 // address, so the user cannot spend it (issue #276).  Naming every address
 // that bears the symbol is the only shape that says what is true; it does not
-// loosen the rule, because a contract outside the set is still a spoof.
+// loosen the rule.  On Ethereum Mainnet, a contract outside the set is still a
+// spoof.
 const KNOWN_SYMBOLS = new Map();
 KNOWN_SYMBOLS.set("ETH", null);
 for (const network of Object.values(NETWORKS)) {
@@ -3988,14 +3998,15 @@ for (const t of TOKENS) {
     }
 }
 
-// Resolve a token symbol from multiple sources, never returning "?".
-function resolveSymbol(tokenAddress, tokenBalances, trackedTokens) {
+// Resolve a token symbol from multiple sources, never returning "?". The token
+// is a contract on the network with chain id `chainId`.
+function resolveSymbol(tokenAddress, tokenBalances, trackedTokens, chainId) {
     const lower = (tokenAddress || "").toLowerCase();
     const tb = (tokenBalances || []).find(
         (t) => t.address.toLowerCase() === lower,
     );
     if (tb && tb.symbol) return tb.symbol;
-    const known = TOKEN_BY_ADDRESS.get(lower);
+    const known = bundledToken(lower, chainId);
     if (known && known.symbol) return known.symbol;
     const tracked = (trackedTokens || []).find(
         (t) => t.address.toLowerCase() === lower,
@@ -4012,5 +4023,6 @@ module.exports = {
     USD_PRICE_FEEDS,
     PRICE_FEED_BY_ADDRESS,
     getTopTokens,
+    bundledToken,
     resolveSymbol,
 };

src/shared/transactions.js

@@ -8,7 +8,7 @@
 
 const { formatEther, formatUnits } = require("ethers");
 const { log, debugFetch } = require("./log");
-const { TOKEN_BY_ADDRESS } = require("./tokenList");
+const { bundledToken } = require("./tokenList");
 const { parseHoldersCount, isLowHolderCount } = require("./holders");
 const { isSpoofedSymbol } = require("./symbolSpoof");
 const { nativeCurrencyByChainId } = require("./networks");
@@ -47,7 +47,7 @@ function parseTx(tx, addrLower, chainId) {
     let direction = normalizeAddress(from) === addrLower ? "sent" : "received";
     let directionLabel = direction === "sent" ? "Sent" : "Received";
     if (toIsContract && method && method !== "transfer") {
-        const token = TOKEN_BY_ADDRESS.get(normalizeAddress(to));
+        const token = bundledToken(to, chainId);
         if (token) {
             symbol = token.symbol;
         }
@@ -317,7 +317,10 @@ function filterTransactions(txs, filters = {}) {
         const contract = normalizeAddress(tx.contractAddress);
 
         // Filter spoofed known symbols and record the fraud contract
-        if (hideSpoofed && isSpoofedSymbol(tx.symbol, tx.contractAddress)) {
+        if (
+            hideSpoofed &&
+            isSpoofedSymbol(tx.symbol, tx.contractAddress, tx.chainId)
+        ) {
             if (contract && !fraudSet.has(contract)) {
                 fraudSet.add(contract);
                 newFraud.push(contract);

src/shared/uniswap.js

@@ -452,8 +452,8 @@ const ADDRESS_THIS = "0x0000000000000000000000000000000000000002";
 // `decimals` is null when nothing knows this token's scale. It is not
 // defaulted to 18: the swap lines land on the same approval screen as the
 // ERC-20 line, and a scale guessed there is what showed a 1,000 USDT swap as
-// 0.000000000001. `sources` is { trackedTokens, wallets }, shaped as they are
-// on `state`; resolveTokenDecimals() reads the bundled list, then those.
+// 0.000000000001. `sources` is as for resolveTokenDecimals(), which reads the
+// bundled list on Ethereum Mainnet, then the tracked tokens and the wallets.
 //
 // A null `address` means UNDETERMINED — the calldata named no currency for
 // that side — and is refused rather than named. It is not native ETH: Uniswap
@@ -479,6 +479,17 @@ function tokenInfo(address, sources) {
     };
 }
 
+// The token of a Permit2 allowance or of a PERMIT2_TRANSFER_FROM, in the
+// shape tokenInfo() gives. Permit2 has no allowance of ETH and moves no ETH.
+// The zero address there reads as a token nothing knows: its amount in base
+// units, and the zero address as its token.
+function permit2TokenInfo(address, sources) {
+    if (address === "0x0000000000000000000000000000000000000000") {
+        return { symbol: null, decimals: null, address };
+    }
+    return tokenInfo(address, sources);
+}
+
 // A swap amount line. With a scale it is the token quantity; with none it is
 // the base-unit integer with the unknown scale stated, the same refusal the
 // ERC-20 amount line makes, so the screen has one way of saying it. `display`
@@ -497,16 +508,18 @@ function amountText(raw, info) {
 
 // The line giving a moved token, or the token of a permit, under `label`, in
 // the shape of the Token In line, so the screens show it as they show that
-// one. ETH has no address.
-function tokenMovedLine(label, token, sources) {
-    const info = tokenInfo(token, sources);
+// one. `info` is what tokenInfo() or permit2TokenInfo() gives for the token.
+// ETH has no address.
+function tokenMovedLine(label, info) {
     if (!present(info.address)) {
         return { label, value: info.symbol };
     }
     return {
         label,
-        value: info.symbol ? info.symbol + " (" + token + ")" : token,
-        address: token,
+        value: info.symbol
+            ? info.symbol + " (" + info.address + ")"
+            : info.address,
+        address: info.address,
         isToken: true,
     };
 }
@@ -975,6 +988,9 @@ function totalAmount(amounts) {
 // pays it of Token In as the step's amount in place of the rules' Amount, or
 // no amount when this decoder cannot tell what that is.
 //
+// `spent` lists the currency that each swap action spends, for each swap
+// action that this decoder could read.
+//
 // `takes` is every TAKE, TAKE_ALL and TAKE_PORTION, as the currency it takes
 // and its recipient as written, MSG_SENDER for a TAKE_ALL. TAKE_PORTION takes
 // a share of the currency, so it does not name the output side as TAKE does.
@@ -1150,6 +1166,8 @@ function decodeV4Swap(input) {
             }
         }
 
+        const spent = swaps.map((s) => s.tokenIn);
+
         // Rule 3.
         if (swapUndecoded) {
             return {
@@ -1157,6 +1175,7 @@ function decodeV4Swap(input) {
                 tokenOut: takeToken,
                 amountIn: null,
                 amountOutMin: null,
+                spent,
                 takes,
                 settledFromRouter,
                 paidByUser,
@@ -1167,7 +1186,6 @@ function decodeV4Swap(input) {
             };
         }
 
-        const spent = swaps.map((s) => s.tokenIn);
         const bought = swaps.map((s) => s.tokenOut);
 
         // Rules 1 and 2 for Token In.
@@ -1203,6 +1221,7 @@ function decodeV4Swap(input) {
             tokenOut,
             amountIn,
             amountOutMin,
+            spent,
             takes,
             settledFromRouter,
             paidByUser,
@@ -1227,6 +1246,9 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
     const release = routerRelease(toAddress, chainId);
     if (release === null) return null;
     const { commandTypeMask, commands, allowRevert } = release;
+    // The swap's tokens are contracts on the network with `chainId`, so they
+    // are named and scaled for that network.
+    const tokenSources = { ...sources, chainId };
     try {
         const parsed = ROUTER_IFACE.parseTransaction({ data });
         if (!parsed) return null;
@@ -1240,10 +1262,15 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         let inputEstablished = false;
         // Whether the user pays the step that set the input side: a V2 or V3
         // swap step with `payerIsUser` true, a V4 step the user pays some of
-        // its input currency (see decodeV4Swap()), or a WRAP_ETH, whose ETH
-        // comes from the transaction's value. A step paid from the router
-        // takes nothing from the sender.
+        // its input currency (see paidByUser in the loop), or a WRAP_ETH,
+        // whose ETH comes from the transaction's value. A step that pays an
+        // ERC-20 token from the router takes none of that token from the
+        // sender.
         let inputPaidByUser = false;
+        // The recipient of a WRAP_ETH that set the input side, as written,
+        // when it is not the router; otherwise null. That WRAP_ETH pays its
+        // WETH there, not to a swap step (see the Moved to lines).
+        let wrapEthRecipient = null;
         // The last PERMIT2_PERMIT this decoder read before a step set the
         // input side, or null (see permitStands after the loop).
         let permit = null;
@@ -1293,8 +1320,9 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         const commandNames = [];
 
         // THE INVARIANT: an amount and the token it is counted in always come
-        // from the same hop, or from hops that all spend that token. A figure
-        // is never rendered against a token that did not supply it.
+        // from the same hop, or from hops that all spend that token or all buy
+        // it. A figure is never rendered against a token that did not supply
+        // it.
         //
         // Both sides are therefore set as a PAIR — never field by field, and
         // never on truthiness. An address is never falsy once set but an
@@ -1338,13 +1366,17 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // What the steps take from the sender beyond the amount of the step
         // that sets the input side, as { token, amount }, in step order.
         // After the loop each joins the Amount line or gets lines of its own
-        // (see permitStands).
+        // (see permitStands). A take with `atMost` set may take less than
+        // `amount`: it never joins the Amount line, and its line reads
+        // "Up to" and the amount.
         const userPaid = [];
         // A swap step the user pays for (`payerIsUser` true) takes `amount`
-        // of `token` from the sender. A V2 exact-in of ALREADY_PAID takes
-        // nothing.
-        const addUserPaid = (token, amount) => {
-            if (amount !== ALREADY_PAID) userPaid.push({ token, amount });
+        // of `token` from the sender, or at most that when `atMost` is set. A
+        // V2 exact-in of ALREADY_PAID takes nothing.
+        const addUserPaid = (token, amount, atMost = false) => {
+            if (amount !== ALREADY_PAID) {
+                userPaid.push({ token, amount, atMost });
+            }
         };
         // A step may take from the sender what this decoder did not read: a
         // V4 step whose input or one of whose SETTLEs or SETTLE_ALLs it
@@ -1407,6 +1439,10 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
             const r = recipient.toLowerCase();
             return r === ADDRESS_THIS || r === toAddress.toLowerCase();
         };
+        const isSender = (recipient) => {
+            const r = recipient.toLowerCase();
+            return r === MSG_SENDER || r === sender;
+        };
         // A swap step or V4 SETTLE pays `amount` of `token` from the router's
         // own balance. CONTRACT_BALANCE pays all of it. Any other quantity
         // counts against the amount a WRAP_ETH stated, and the steps pay all
@@ -1439,17 +1475,73 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // A step pays `recipient`. `output` is the token a swap step or a V4
         // TAKE or TAKE_PORTION pays; other steps pass none.
         const addPayee = (recipient, output) => {
-            const r = recipient.toLowerCase();
             if (isRouter(recipient)) {
                 if (present(output)) {
                     heldByRouter.set(output.toLowerCase(), null);
                 }
-            } else if (r === MSG_SENDER || r === sender) {
+            } else if (isSender(recipient)) {
                 paidToSender = true;
             } else {
                 addPaidElsewhere(recipient);
             }
         };
+        // Each swap step that paid the sender some of the token it bought,
+        // as { step, token, amount, onlyToSender }:
+        // - `step` is the step's index;
+        // - `token` is that token;
+        // - `amount` is the step's stated minimum;
+        // - `onlyToSender` is whether the step paid all of that token to the
+        //   sender.
+        // A later step that spends that token takes the step off this list
+        // (see dropFromSum()).
+        let swapsPayingSender = [];
+        // The step being read spends `token`, so it may spend what an earlier
+        // swap step paid the sender. Each step on swapsPayingSender that
+        // bought `token` leaves the list. A step spends a token as follows:
+        // - a V2 or V3 swap step spends its input token;
+        // - a V4 step spends each token that one of its swap actions spends,
+        //   and each token that one of its SETTLEs or SETTLE_ALLs pays;
+        // - a PERMIT2_TRANSFER_FROM spends the token it moves.
+        const dropFromSum = (token) => {
+            swapsPayingSender = swapsPayingSender.filter(
+                (s) => !sameAddress(s.token, token),
+            );
+        };
+        // The minimum the output side shows for the swap step at `step`. The
+        // step buys `token` with the stated minimum `amount`, and pays
+        // `token` to `recipients`. The minimum is the step's own, unless this
+        // step and an earlier one on swapsPayingSender both pay `token` to
+        // the sender, as a route split across steps does. The minimum is then
+        // the total of all such steps' minimums. There is none when this
+        // decoder reads no minimum from one of them, or when one of them pays
+        // some of `token` elsewhere. There is also none when this decoder did
+        // not read one of them, or a step between them, in full (see
+        // stepsUnread).
+        const swapMinimum = (step, token, amount, recipients) => {
+            const toSender = recipients.filter(
+                (r) => present(r) && isSender(r),
+            );
+            if (toSender.length === 0) return amount;
+            swapsPayingSender.push({
+                step,
+                token,
+                amount,
+                onlyToSender: toSender.length === recipients.length,
+            });
+            const split = swapsPayingSender.filter((s) =>
+                sameAddress(s.token, token),
+            );
+            if (split.length < 2) return amount;
+            if (
+                split.some(
+                    (s) => !s.onlyToSender || typeof s.amount !== "bigint",
+                ) ||
+                stepsUnread.some((unread) => unread >= split[0].step)
+            ) {
+                return null;
+            }
+            return split.reduce((sum, s) => sum + s.amount, 0n);
+        };
         // A step that pays `token` to `recipient` is a hop, not a payout,
         // when the very next step is a V2 exact-in whose input is already
         // paid, whose path starts at `token`, and whose pair (see v2PairFor())
@@ -1591,6 +1683,7 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                                     : null,
                         });
                     }
+                    if (p) dropFromSum(p.token);
                 } else if (command === "BALANCE_CHECK_ERC20") {
                     const b = decodeBalanceCheck(inputs[i]);
                     if (!b) {
@@ -1613,13 +1706,13 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                     } else {
                         // The router passes this check whenever the owner
                         // holds at least minBalance, so a zero one guarantees
-                        // nothing and does not replace a minimum an earlier
-                        // step stated. A check the router lets fail guarantees
-                        // nothing either, so it is read as a zero one. Any
+                        // nothing. A check the router lets fail guarantees
+                        // nothing either, so it is read as a zero one. A zero
+                        // check sets neither Token Out nor the minimum. Any
                         // other minBalance sets the output side as a swap
-                        // does. It pays nobody.
+                        // does. The check pays nobody.
                         const minBalance = allowedToFail ? 0n : b.minBalance;
-                        if (!(minBalance === 0n && present(minOutput))) {
+                        if (minBalance !== 0n) {
                             setOutput(i, b.token, minBalance, []);
                         }
                         keepsRouterWeth = true;
@@ -1633,10 +1726,18 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                         } else if (s.payerIsUser) {
                             addUserPaid(s.tokenIn, s.amountIn);
                         }
+                        dropFromSum(s.tokenIn);
                         // Always update output: in multi-step swaps (V3 → V4),
-                        // the last swap step determines the final output token
-                        // and minimum received amount.
-                        setOutput(i, s.tokenOut, s.amountOutMin, [s.recipient]);
+                        // the last swap step determines the final output
+                        // token. swapMinimum() gives the minimum.
+                        setOutput(
+                            i,
+                            s.tokenOut,
+                            swapMinimum(i, s.tokenOut, s.amountOutMin, [
+                                s.recipient,
+                            ]),
+                            [s.recipient],
+                        );
                         if (!s.payerIsUser) {
                             spendFromRouter(s.tokenIn, s.amountIn);
                         }
@@ -1657,7 +1758,15 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                         } else if (s.payerIsUser) {
                             addUserPaid(s.tokenIn, s.amountIn);
                         }
-                        setOutput(i, s.tokenOut, s.amountOutMin, [s.recipient]);
+                        dropFromSum(s.tokenIn);
+                        setOutput(
+                            i,
+                            s.tokenOut,
+                            swapMinimum(i, s.tokenOut, s.amountOutMin, [
+                                s.recipient,
+                            ]),
+                            [s.recipient],
+                        );
                         if (!s.payerIsUser) {
                             spendFromRouter(s.tokenIn, s.amountIn);
                         }
@@ -1689,7 +1798,15 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                         } else if (s.payerIsUser) {
                             addUserPaid(s.tokenIn, s.amountInMax);
                         }
-                        setOutput(i, s.tokenOut, s.amountOut, [s.recipient]);
+                        dropFromSum(s.tokenIn);
+                        setOutput(
+                            i,
+                            s.tokenOut,
+                            swapMinimum(i, s.tokenOut, s.amountOut, [
+                                s.recipient,
+                            ]),
+                            [s.recipient],
+                        );
                         if (!isHop(i, s.tokenOut, s.recipient)) {
                             addPayee(s.recipient, s.tokenOut);
                         }
@@ -1787,6 +1904,9 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                                 w.amount,
                             );
                             inputPaidByUser = true;
+                            if (!isRouter(w.recipient)) {
+                                wrapEthRecipient = w.recipient;
+                            }
                         }
                         addPayee(w.recipient);
                         // CONTRACT_BALANCE wraps all the router's ETH.
@@ -1815,6 +1935,41 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                 } else if (command === "V4_SWAP") {
                     const v4 = decodeV4Swap(inputs[i]);
                     const inputSetBefore = inputEstablished;
+                    // V4Router pays a SETTLE of ETH from the router's own
+                    // ETH, whichever payer the SETTLE names. The router holds
+                    // the transaction's value, and any ETH an earlier step
+                    // left it (see heldByRouter). So the user also pays a
+                    // SETTLE of ETH that names the router as payer. The user
+                    // pays all of its amount when the router holds no other
+                    // ETH, and up to its amount otherwise. CONTRACT_BALANCE
+                    // pays all the router holds, an amount the calldata does
+                    // not state.
+                    const routerHeldEth = heldByRouter.has(
+                        "0x0000000000000000000000000000000000000000",
+                    );
+                    const ethFromRouter = (v4?.settledFromRouter ?? [])
+                        .filter(
+                            (s) =>
+                                s.currency ===
+                                "0x0000000000000000000000000000000000000000",
+                        )
+                        .map((s) => ({
+                            currency: s.currency,
+                            amount:
+                                s.amount === CONTRACT_BALANCE ? null : s.amount,
+                        }));
+                    // What the user pays the step: what decodeV4Swap() says,
+                    // and the ETH of each SETTLE from the router of a known
+                    // amount when the router holds no other ETH.
+                    const paidByUser = v4
+                        ? v4.paidByUser.concat(
+                              routerHeldEth
+                                  ? []
+                                  : ethFromRouter.filter((s) =>
+                                        present(s.amount),
+                                    ),
+                          )
+                        : [];
                     if (v4) {
                         // Each SETTLE paid from the router spends the amount
                         // decodeV4Swap() says it pays.
@@ -1826,6 +1981,11 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                                 addPayee(t.recipient, t.currency);
                             }
                         }
+                        for (const token of v4.spent) dropFromSum(token);
+                        for (const s of v4.paidByUser) dropFromSum(s.currency);
+                        for (const s of v4.settledFromRouter) {
+                            dropFromSum(s.currency);
+                        }
                     }
                     if (!v4 || v4.recipientUnread) {
                         payeeUnread = true;
@@ -1845,10 +2005,10 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                         commandNames[i] += " (could not be decoded)";
                     }
                     // The step's amount, if it sets the input side: what the
-                    // user pays it of its input currency (see
-                    // decodeV4Swap()), or, when the user pays none of it,
-                    // what its swap actions spend of it, whoever pays that.
-                    const paidIn = v4?.paidByUser.find(
+                    // user pays it of its input currency, or, when the user
+                    // pays none of it, what its swap actions spend of it,
+                    // whoever pays that.
+                    const paidIn = paidByUser.find(
                         (p) => p.currency === v4.tokenIn,
                     );
                     const amountIn = paidIn ? paidIn.amount : v4?.amountIn;
@@ -1874,7 +2034,12 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                             setInput(v4.tokenIn, amountIn);
                         }
                         outputToken = v4.tokenOut;
-                        minOutput = v4.amountOutMin;
+                        minOutput = swapMinimum(
+                            i,
+                            v4.tokenOut,
+                            v4.amountOutMin,
+                            takeRecipients,
+                        );
                         outputEstablished = true;
                         outputUnwrapped = false;
                         unwrapIntoRouterStep = null;
@@ -1902,10 +2067,33 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                     // router still runs it.
                     const setInputHere = inputEstablished && !inputSetBefore;
                     if (setInputHere) inputPaidByUser = paidIn !== undefined;
-                    if (v4) {
-                        for (const p of v4.paidByUser) {
-                            if (setInputHere && p === paidIn) continue;
-                            addUserPaid(p.currency, p.amount);
+                    // ETH an earlier step left in the router may pay part of
+                    // the ETH that the user pays this step. The sender then
+                    // pays at most that amount.
+                    for (const p of paidByUser) {
+                        if (setInputHere && p === paidIn) continue;
+                        addUserPaid(
+                            p.currency,
+                            p.amount,
+                            routerHeldEth &&
+                                p.currency ===
+                                    "0x0000000000000000000000000000000000000000",
+                        );
+                    }
+                    // A SETTLE of ETH from the router that `paidByUser` leaves
+                    // out is a take of its own, even on the step that sets
+                    // the input side. Either this decoder does not know its
+                    // amount, or ETH an earlier step left in the router may
+                    // pay part of that amount (see userPaid).
+                    for (const p of ethFromRouter) {
+                        if (!present(p.amount)) {
+                            addUserPaid(p.currency, null);
+                        } else if (routerHeldEth) {
+                            userPaid.push({
+                                token: p.currency,
+                                amount: p.amount,
+                                atMost: true,
+                            });
                         }
                     }
                     if (!v4 || v4.settleUnread) {
@@ -2013,10 +2201,10 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // The total is what the steps take of Token In: the amount of the
         // step that set the input side, with each later take of that token
         // added to it while both are quantities. A take that cannot be added,
-        // being of another token or coming after an amount that is not a
-        // quantity (a V4 open delta, ALREADY_PAID, or none stated), gets
-        // lines of its own. One whose amount is not known also leaves the
-        // total unknown, with no figure.
+        // being of another token, coming after an amount that is not a
+        // quantity (a V4 open delta, ALREADY_PAID, or none stated), or having
+        // `atMost` set, gets lines of its own. One whose amount is not known
+        // also leaves the total unknown, with no figure.
         //
         // A PERMIT2_PERMIT names Token In only when its amount stands as the
         // Amount figure in place of the total, which it does only in the
@@ -2032,12 +2220,14 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // it may take more. A later permit or batch, or a later step this
         // decoder did not read, may raise what Permit2 lets the router take.
         // Every other PERMIT2_PERMIT leaves Token In and the Amount line as
-        // they read with no permit, and gets lines of its own below. A step
-        // that may take from the sender what this decoder did not read leaves
-        // no figure, permit or not (see spentUnread()), and so do a permit
-        // or batch whose input it cannot read (see permitUnread()) and an
-        // allowance of Token In to another spender (see toAnotherSpender). An
-        // EXECUTE_SUB_PLAN step leaves both sides unknown (below).
+        // they read with no permit, and gets lines of its own below. A permit
+        // on the zero address never stands as the Amount figure, because
+        // Permit2 has no allowance of ETH. A step that may take from the
+        // sender what this decoder did not read leaves no figure, permit or
+        // not (see spentUnread()), and so do a permit or batch whose input it
+        // cannot read (see permitUnread()) and an allowance of Token In to
+        // another spender (see toAnotherSpender). An EXECUTE_SUB_PLAN step
+        // leaves both sides unknown (below).
         const stepCommands = Array.from(
             commandsBytes,
             (b) => commands[b & commandTypeMask],
@@ -2047,24 +2237,27 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
             stepCommands.filter((c) => c === "PERMIT2_PERMIT").length === 1 &&
             !stepCommands.includes("PERMIT2_PERMIT_BATCH") &&
             sameAddress(permit.spender, toAddress) &&
+            permit.token !== "0x0000000000000000000000000000000000000000" &&
             !permit.allowedToFail &&
             permit.beforeEveryTake &&
             !stepsUnread.some((step) => step > permit.step);
         // What the steps take that the Amount line does not give, as
-        // { token, amount }. A null token is a step this decoder did not read
-        // (see spentUnread()), or a token it does not know.
+        // { token, amount, atMost, recipient }. A null token is a step this
+        // decoder did not read (see spentUnread()), or a token it does not
+        // know. `atMost` is as in `userPaid`. Only the take of a WRAP_ETH that
+        // pays elsewhere has a recipient (see wrapEthRecipient).
         const spentFromSender = [];
         let total = null;
-        // The takes from the sender that `total` adds up, each a quantity, as
-        // { token, amount }. When there is no Amount line, each gets lines of
-        // its own (see below). The amount of a step that set the input side
-        // and is paid from the router counts in `total` but is not among them.
+        // The takes from the sender that `total` adds up, each a quantity, in
+        // the shape of `spentFromSender`. When there is no Amount line, each
+        // gets lines of its own (see below). The amount of the step that set
+        // the input side counts in `total` whoever pays that step. That amount
+        // is among them only when the user pays the step (see inputPaidByUser).
         const inTotal = [];
         // Whether the step that set the input side counts as a take from the
         // sender, which may get lines of its own. The amount it stated counts
         // whoever pays it. Stating none, it counts only when the user pays it
-        // some of its input token: paid from the router, it takes nothing
-        // from the sender.
+        // some of its input token.
         const hasFirstTake =
             inputEstablished && (present(inputAmount) || inputPaidByUser);
         // The take of the step that set the input side, when the total
@@ -2073,7 +2266,11 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         if (!permitStands || sameAddress(inputToken, permit.token)) {
             total = inputAmount;
             if (typeof inputAmount === "bigint" && inputPaidByUser) {
-                inTotal.push({ token: inputToken, amount: inputAmount });
+                inTotal.push({
+                    token: inputToken,
+                    amount: inputAmount,
+                    recipient: wrapEthRecipient,
+                });
             }
             if (hasFirstTake && !present(inputAmount)) {
                 firstTakeUnstated = { token: inputToken, amount: null };
@@ -2081,7 +2278,11 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         } else if (hasFirstTake) {
             // The step that set the input side spent a token other than the
             // permit's, or one not known, so its amount gets lines of its own.
-            spentFromSender.push({ token: inputToken, amount: inputAmount });
+            spentFromSender.push({
+                token: inputToken,
+                amount: inputAmount,
+                recipient: wrapEthRecipient,
+            });
         }
         if (permitStands) inputToken = permit.token;
         for (const t of userPaid) {
@@ -2090,7 +2291,8 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
             if (
                 ofTokenIn &&
                 typeof total === "bigint" &&
-                typeof t.amount === "bigint"
+                typeof t.amount === "bigint" &&
+                !t.atMost
             ) {
                 total += t.amount;
                 inTotal.push(t);
@@ -2139,11 +2341,11 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // Any other output keeps its own token and figure: a swap that pays
         // its WETH to the user and then unwraps receives WETH, and one that
         // buys USDC and then unwraps the WETH it did not spend receives USDC.
-        const inInfo = tokenInfo(inputToken, sources);
+        const inInfo = tokenInfo(inputToken, tokenSources);
         const outInfo =
             outputUnwrapped || (hasUnwrapWeth && !outputEstablished)
                 ? { symbol: "ETH", decimals: 18, address: null }
-                : tokenInfo(outputToken, sources);
+                : tokenInfo(outputToken, tokenSources);
 
         const inSymbol = inInfo.symbol;
         const outSymbol = outInfo.symbol;
@@ -2193,8 +2395,9 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // V2's already-paid zero, neither of which is a quantity at all (see
         // OPEN_DELTA and ALREADY_PAID), and an unbounded permit. Those two
         // tests come first — the sentinels are not bigints and cannot be
-        // compared with one.
-        const spentText = (amount, info) => {
+        // compared with one. `atMost` marks an amount that is only the most a
+        // take may be (see userPaid).
+        const spentText = (amount, info, atMost) => {
             if (amount === OPEN_DELTA) {
                 return { raw: OPEN_DELTA_AMOUNT, display: OPEN_DELTA_AMOUNT };
             }
@@ -2207,7 +2410,7 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
             if (amount >= MAX_UINT160) {
                 return { raw: "Unlimited", display: "Unlimited" };
             }
-            if (hasV2OrV3ExactOut) {
+            if (hasV2OrV3ExactOut || atMost) {
                 // A V2 or V3 exact-out swap spends at most this figure,
                 // whichever steps gave it (an amountInMax, the WRAP_ETH of a
                 // swap paid in ETH, a permit, or several steps' total), so it
@@ -2234,17 +2437,19 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // A null token in `spentFromSender`, a step this decoder did not read
         // or a token it does not know, and an allowance to another spender
         // that may be of Token In, leave no Amount figure, which may then be
-        // too low. With no Amount line, each take the total adds up gets
-        // lines of its own, first, so that every amount this decoder read is
-        // shown.
+        // too low. An allowance of the zero address is never one of Token In,
+        // because Permit2 has no allowance of ETH. With no Amount line, each
+        // take the total adds up gets lines of its own, first, so that every
+        // amount this decoder read is shown.
         if (
             present(inputAmount) &&
             spentFromSender.every((s) => present(s.token)) &&
             toAnotherSpender.every(
                 (p) =>
-                    present(p.token) &&
-                    present(inputToken) &&
-                    !sameAddress(p.token, inputToken),
+                    p.token === "0x0000000000000000000000000000000000000000" ||
+                    (present(p.token) &&
+                        present(inputToken) &&
+                        !sameAddress(p.token, inputToken)),
             )
         ) {
             const amount = spentText(inputAmount, inInfo);
@@ -2260,32 +2465,53 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // What steps take from the sender beyond the Amount line, in the shape
         // of the lines below for a PERMIT2_TRANSFER_FROM. An amount this
         // decoder does not know is said so, and a step it did not read gets
-        // that one line alone.
+        // that one line alone. A take with no recipient goes to the swap step
+        // that spends it. A take with a recipient goes to that recipient;
+        // `MSG_SENDER` means the sender.
         for (const s of spentFromSender) {
             details.push({
                 label: "Moved from the sender",
                 value: present(s.amount)
-                    ? spentText(s.amount, tokenInfo(s.token, sources)).display
+                    ? spentText(
+                          s.amount,
+                          tokenInfo(s.token, tokenSources),
+                          s.atMost,
+                      ).display
                     : UNDECODED_CURRENCY,
             });
             if (present(s.token)) {
-                details.push(tokenMovedLine("Token moved", s.token, sources));
-                details.push({
-                    label: "Moved to",
-                    value: "The swap step that spends it",
-                });
+                details.push(
+                    tokenMovedLine(
+                        "Token moved",
+                        tokenInfo(s.token, tokenSources),
+                    ),
+                );
+                if (!present(s.recipient)) {
+                    details.push({
+                        label: "Moved to",
+                        value: "The swap step that spends it",
+                    });
+                } else if (s.recipient.toLowerCase() === MSG_SENDER) {
+                    details.push({ label: "Moved to", value: "The sender" });
+                } else {
+                    details.push({
+                        label: "Moved to",
+                        value: s.recipient,
+                        address: s.recipient,
+                    });
+                }
             }
         }
 
         // What each PERMIT2_TRANSFER_FROM moves: its amount, its token and
         // where it goes, an address on a line of its own.
         for (const m of movedFromSender) {
+            const info = permit2TokenInfo(m.token, tokenSources);
             details.push({
                 label: "Moved from the sender",
-                value: amountText(m.amount, tokenInfo(m.token, sources))
-                    .display,
+                value: amountText(m.amount, info).display,
             });
-            details.push(tokenMovedLine("Token moved", m.token, sources));
+            details.push(tokenMovedLine("Token moved", info));
             details.push(
                 present(m.to)
                     ? { label: "Moved to", value: m.to }
@@ -2315,15 +2541,15 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                 });
                 continue;
             }
+            const info = permit2TokenInfo(p.token, tokenSources);
             details.push({
                 label: "Permit2 allowance",
                 value:
                     p.amount >= MAX_UINT160
                         ? "Unlimited"
-                        : amountText(p.amount, tokenInfo(p.token, sources))
-                              .display,
+                        : amountText(p.amount, info).display,
             });
-            details.push(tokenMovedLine("Allowance token", p.token, sources));
+            details.push(tokenMovedLine("Allowance token", info));
             details.push({
                 label: "Allowance spender",
                 value: p.spender,
@@ -2381,7 +2607,7 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
             paidTo.push({ label: "Paid to", value: PAID_TO_BRIDGE });
         }
         for (const m of movedIntoRouter) {
-            const info = tokenInfo(m.token, sources);
+            const info = permit2TokenInfo(m.token, tokenSources);
             paidTo.push({
                 label: "Paid to",
                 value:
@@ -2389,9 +2615,7 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                     amountText(m.amount, info).display +
                     " from the sender (later steps may not spend all of it)",
             });
-            paidTo.push(
-                tokenMovedLine("Token moved into the router", m.token, sources),
-            );
+            paidTo.push(tokenMovedLine("Token moved into the router", info));
         }
         if (outputHeld) {
             paidTo.push({ label: "Paid to", value: STAYS_IN_ROUTER });
@@ -2408,8 +2632,7 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
             paidTo.push(
                 tokenMovedLine(
                     "Token moved into the router",
-                    getAddress(token),
-                    sources,
+                    tokenInfo(getAddress(token), tokenSources),
                 ),
             );
         }

tests/addTokenLateAnswer.test.js

@@ -0,0 +1,138 @@
+// A contract lookup on AddToken can answer after the user has left AddToken.
+// The token is still added, and the screen the user is on does not change
+// (https://git.eeqj.de/sneak/AutistMask/issues/603). An answer while AddToken
+// still shows goes to AddressDetail. Driven through the real popup over a
+// stored profile.
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    TOKEN_ADDRESS,
+} = require("./support/popupBoot");
+
+const TOKEN = {
+    address: TOKEN_ADDRESS,
+    symbol: "TST",
+    decimals: 18,
+    name: "Test Token",
+    balanceNotFetched: true,
+};
+
+// A second contract address, typed after AddToken was opened again.
+const OTHER_TOKEN_ADDRESS = "0xBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB";
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+// The popup reopened onto AddressDetail, then AddToken opened from it with
+// TOKEN's contract address typed in.
+async function openAddToken() {
+    const boot = await bootPopup(
+        unversionedValidProfile({
+            currentView: "address",
+            selectedWallet: 0,
+            selectedAddress: 0,
+        }),
+    );
+    expect(boot.pageErrors).toEqual([]);
+    await boot.click("btn-add-token");
+    expect(boot.visibleViews()).toEqual(["add-token"]);
+    boot.node("add-token-address").value = TOKEN.address;
+    return boot;
+}
+
+// Presses Add with a contract lookup that answers only when the function
+// returned here is called. That function waits for Add to finish.
+function addWithPendingLookup(boot) {
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    let answer;
+    lookupTokenInfo.mockImplementationOnce(
+        () =>
+            new Promise((resolve) => {
+                answer = resolve;
+            }),
+    );
+    const adding = boot.click("btn-add-token-confirm");
+    return async () => {
+        answer({
+            symbol: TOKEN.symbol,
+            decimals: TOKEN.decimals,
+            name: TOKEN.name,
+        });
+        await adding;
+    };
+}
+
+test("an answer after the user opened Settings adds the token and Settings stays", async () => {
+    const boot = await openAddToken();
+    const answerLookup = addWithPendingLookup(boot);
+    await boot.click("btn-settings");
+    expect(boot.visibleViews()).toEqual(["settings"]);
+
+    await answerLookup();
+    expect(boot.visibleViews()).toEqual(["settings"]);
+    expect(boot.storage.read("autistmask").trackedTokens).toEqual([TOKEN]);
+});
+
+test("Back from Settings onto AddToken after the lookup answered shows no lookup status", async () => {
+    const boot = await openAddToken();
+    const answerLookup = addWithPendingLookup(boot);
+    expect(boot.text("add-token-info")).toBe("Looking up token...");
+    await boot.click("btn-settings");
+    await answerLookup();
+
+    await boot.click("btn-settings-back");
+    expect(boot.visibleViews()).toEqual(["add-token"]);
+    expect(boot.text("add-token-info")).toBe("");
+    expect(boot.node("add-token-info").style.visibility).toBe("hidden");
+});
+
+test("an answer after AddToken was opened again adds the token and leaves AddToken and its status line as they are", async () => {
+    const boot = await openAddToken();
+    const answerFirstLookup = addWithPendingLookup(boot);
+    await boot.click("btn-add-token-back");
+    await boot.click("btn-add-token");
+    expect(boot.visibleViews()).toEqual(["add-token"]);
+    boot.node("add-token-address").value = OTHER_TOKEN_ADDRESS;
+    // The second lookup is never answered.
+    addWithPendingLookup(boot);
+
+    await answerFirstLookup();
+    expect(boot.visibleViews()).toEqual(["add-token"]);
+    expect(boot.text("add-token-info")).toBe("Looking up token...");
+    expect(boot.storage.read("autistmask").trackedTokens).toEqual([TOKEN]);
+});
+
+test("a lookup that fails after AddToken was opened again leaves the status line as it is", async () => {
+    const boot = await openAddToken();
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    let failFirstLookup;
+    lookupTokenInfo.mockImplementationOnce(
+        () =>
+            new Promise((_, reject) => {
+                failFirstLookup = reject;
+            }),
+    );
+    const firstAdd = boot.click("btn-add-token-confirm");
+    await boot.click("btn-add-token-back");
+    await boot.click("btn-add-token");
+    boot.node("add-token-address").value = OTHER_TOKEN_ADDRESS;
+    // The second lookup is never answered.
+    addWithPendingLookup(boot);
+
+    failFirstLookup(new Error("lookup failed"));
+    await firstAdd;
+    expect(boot.text("add-token-info")).toBe("Looking up token...");
+});
+
+test("an answer while AddToken still shows goes to AddressDetail with the token listed", async () => {
+    const boot = await openAddToken();
+    const answerLookup = addWithPendingLookup(boot);
+
+    await answerLookup();
+    expect(boot.visibleViews()).toEqual(["address"]);
+    expect(boot.node("address-balances").innerHTML).toContain("TST");
+    expect(boot.storage.read("autistmask").trackedTokens).toEqual([TOKEN]);
+});

tests/addedTokenBalance.test.js

@@ -0,0 +1,458 @@
+// After "Add" on AddToken, AddressDetail lists the new token. Its line reads
+// `quantity unknown`, not 0.0000, until a balance refresh has read the token's
+// balance at every address, even if the popup closes and opens again
+// meanwhile. A token added on SettingsAddToken reads the same 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).
+//
+// The tracked token's record carries `balanceNotFetched` until a refresh has
+// read the token's balance. Removing the token removes that record. A network
+// switch keeps each network's records apart. A refresh takes the field off the
+// stored record's tokens and keeps another page's changes to the stored list.
+//
+// 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";
+
+// A holding of a million NEW_TOKEN, as refreshBalances() stores it.
+const MILLION = {
+    address: NEW_TOKEN,
+    name: "New Token",
+    symbol: "NEW",
+    decimals: 18,
+    balance: "1000000.0",
+    holders: 3,
+};
+
+// NEW_TOKEN as "Add" on AddToken tracks it, once a refresh has read its
+// balance.
+const NEW_TRACKED = {
+    address: NEW_TOKEN,
+    symbol: "NEW",
+    name: "New Token",
+    decimals: 18,
+};
+
+// A token that another popup page tracks.
+const OTHER_TOKEN = {
+    address: "0xCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC",
+    symbol: "OTH",
+    name: "Other Token",
+    decimals: 18,
+};
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+// The popup reopened onto AddressDetail for the one address.
+function bootOnAddress(extra) {
+    return bootPopup(
+        unversionedValidProfile({
+            currentView: "address",
+            selectedWallet: 0,
+            selectedAddress: 0,
+            ...extra,
+        }),
+    );
+}
+
+// Holds the next balance refresh open. The returned function lets it finish
+// with the address's ETH balance at 2 and `tokenBalances` as its token
+// entries, having read the balance of every token tracked when it started.
+// Given null, it finishes having read no token's balance, as when every
+// balanceOf fails, and leaves the token entries as they were.
+function holdNextRefresh(page) {
+    const { refreshBalances } = require("../src/shared/balances");
+    let release;
+    refreshBalances.mockImplementationOnce(
+        async (wallets, rpcUrl, explorerUrl, trackedTokens) => {
+            const read = trackedTokens.map((t) => t.address.toLowerCase());
+            const tokenBalances = await new Promise((resolve) => {
+                release = resolve;
+            });
+            wallets[0].addresses[0].balance = "2.0";
+            if (tokenBalances === null) return [];
+            wallets[0].addresses[0].tokenBalances = tokenBalances;
+            return read;
+        },
+    );
+    return async (tokenBalances) => {
+        release(tokenBalances);
+        await page.settle();
+    };
+}
+
+// Runs the ten-second refresh to the end, finishing it as holdNextRefresh()
+// does with `tokenBalances`.
+async function refreshOnce(page, tokenBalances) {
+    const finish = holdNextRefresh(page);
+    const ticking = page.tick();
+    await page.settle();
+    await finish(tokenBalances);
+    await ticking;
+}
+
+// "+ 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");
+}
+
+// Settings' "+ Add token", NEW_TOKEN typed in, and "Add", with the contract
+// lookup answering at once. It ends on SettingsAddToken.
+async function addOnSettingsAddToken(page) {
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    lookupTokenInfo.mockResolvedValueOnce({
+        symbol: "NEW",
+        decimals: 18,
+        name: "New Token",
+    });
+    await page.click("btn-settings-add-token");
+    page.node("settings-addtoken-address").value = NEW_TOKEN;
+    await page.click("btn-settings-addtoken-manual");
+}
+
+// The "[x]" button Settings draws beside the first tracked token. The page
+// stub does not turn the markup Settings draws into elements. So the list
+// hands Settings a stand-in for that button each time it is drawn, and
+// `press()` presses the last one drawn. Call it before Settings opens.
+function firstRemoveButton(page) {
+    const button = { press: null };
+    page.node("settings-tracked-tokens").querySelectorAll = () => [
+        {
+            dataset: { idx: "0" },
+            addEventListener: (name, fn) => {
+                button.press = fn;
+            },
+        },
+    ];
+    return button;
+}
+
+// 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();
+}
+
+// Another popup page saves `trackedTokens` as the tracked token list. This
+// page is not told of the write.
+function anotherPageTracks(page, trackedTokens) {
+    page.storage.write("autistmask", {
+        ...page.storage.read("autistmask"),
+        trackedTokens,
+    });
+}
+
+// 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 reading its balance", 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 reads the token's balance, which is zero.
+    await refreshOnce(page, []);
+
+    expect(newTokenRow(page)).toContain("0.0000");
+});
+
+test("closed and opened again before any refresh has read its balance, 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 reads no token's balance: the boot's stub
+    // of refreshBalances() reads 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");
+
+    await refreshOnce(page, [MILLION]);
+
+    expect(newTokenRow(page)).toContain("1000000.0000");
+});
+
+test("a refresh that could not read the new token's balance leaves its 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("Send for the new token reads its balance as unknown before any refresh has read it, and Max says so", async () => {
+    const page = await bootOnAddress();
+    const finish = holdNextRefresh(page);
+    await addNewToken(page);
+    await openToken(page, NEW_TOKEN.toLowerCase());
+
+    await page.click("btn-address-token-send");
+
+    expect(page.visibleViews()).toEqual(["send"]);
+    expect(page.text("send-balance")).toBe("Current balance: unknown (NEW)");
+
+    await page.click("btn-send-max");
+
+    expect(page.text("flash-msg")).toBe("This token's balance is unknown.");
+    await finish([MILLION]);
+});
+
+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);
+
+    await page.click("btn-settings");
+    await addOnSettingsAddToken(page);
+    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");
+
+    await refreshOnce(page, null);
+
+    expect(page.node("address-token-balance").innerHTML).toContain("2.0000");
+});
+
+test("a token removed before any refresh has read its balance leaves nothing stored, and adding it again tracks it once", async () => {
+    const page = await bootPopup(unversionedValidProfile());
+    const removeButton = firstRemoveButton(page);
+    const stored = () => page.storage.read("autistmask");
+
+    await page.click("btn-settings");
+    await addOnSettingsAddToken(page);
+    // Settings opened again from Home draws its list with the token in it.
+    await page.click("btn-settings-addtoken-back");
+    await page.click("btn-settings-back");
+    await page.click("btn-settings");
+    await removeButton.press();
+    await page.settle();
+
+    expect(stored().trackedTokens).toEqual([]);
+    // Nothing in the stored record names the token any more.
+    expect(JSON.stringify(stored()).toLowerCase()).not.toContain(
+        NEW_TOKEN.toLowerCase(),
+    );
+
+    await addOnSettingsAddToken(page);
+    // A second add of the same token is refused.
+    page.node("settings-addtoken-address").value = NEW_TOKEN;
+    await page.click("btn-settings-addtoken-manual");
+
+    const added = { address: NEW_TOKEN, symbol: "NEW", decimals: 18 };
+    expect(stored().trackedTokens).toEqual([
+        { ...added, name: "New Token", balanceNotFetched: true },
+    ]);
+
+    await refreshOnce(page, []);
+
+    expect(stored().trackedTokens).toEqual([{ ...added, name: "New Token" }]);
+});
+
+test("a refresh on another network leaves the new token reading quantity unknown on its own", async () => {
+    // Sepolia tracks a token at the same contract address, also just added.
+    const sepoliaToken = {
+        address: NEW_TOKEN,
+        symbol: "SEP",
+        name: "Sepolia Token",
+        decimals: 18,
+    };
+    const page = await bootOnAddress({
+        networkTrackedTokens: {
+            sepolia: [{ ...sepoliaToken, balanceNotFetched: true }],
+        },
+    });
+    const finishMainnet = holdNextRefresh(page);
+    await addNewToken(page);
+
+    await page.click("btn-settings");
+    await chooseNetwork(page, "sepolia");
+    // The refresh Add started returns after the switch and writes nothing.
+    await finishMainnet([MILLION]);
+    // Sepolia's refresh reads the balance of its own token.
+    await refreshOnce(page, []);
+
+    const stored = page.storage.read("autistmask");
+    expect(stored.trackedTokens).toEqual([sepoliaToken]);
+    expect(stored.networkTrackedTokens.mainnet[0].balanceNotFetched).toBe(true);
+
+    await chooseNetwork(page, "mainnet");
+    await page.click("btn-settings-back");
+
+    expect(page.visibleViews()).toEqual(["address"]);
+    expect(newTokenRow(page)).toContain("quantity unknown");
+
+    await refreshOnce(page, [MILLION]);
+
+    expect(newTokenRow(page)).toContain("1000000.0000");
+});
+
+test("a refresh keeps a token that another page added after this page loaded", async () => {
+    const page = await bootOnAddress();
+    const finish = holdNextRefresh(page);
+    await addNewToken(page);
+    const otherAdded = { ...OTHER_TOKEN, balanceNotFetched: true };
+    anotherPageTracks(page, [
+        { ...NEW_TRACKED, balanceNotFetched: true },
+        otherAdded,
+    ]);
+
+    await finish([MILLION]);
+
+    expect(page.storage.read("autistmask").trackedTokens).toEqual([
+        NEW_TRACKED,
+        otherAdded,
+    ]);
+    expect(newTokenRow(page)).toContain("1000000.0000");
+});
+
+test("a refresh does not bring back a token that another page removed after this page loaded", async () => {
+    const page = await bootOnAddress({ trackedTokens: [OTHER_TOKEN] });
+    const finish = holdNextRefresh(page);
+    await addNewToken(page);
+    anotherPageTracks(page, [{ ...NEW_TRACKED, balanceNotFetched: true }]);
+
+    await finish([MILLION]);
+
+    expect(page.storage.read("autistmask").trackedTokens).toEqual([
+        NEW_TRACKED,
+    ]);
+});

tests/addressKey.test.js

@@ -161,7 +161,7 @@ function click(element) {
 
 // show() starts the fee estimate without awaiting it; this lets it settle.
 async function settle() {
-    for (let i = 0; i < 10; i++) await new Promise((r) => setTimeout(r, 0));
+    for (let i = 0; i < 10; i++) await jest.advanceTimersByTimeAsync(0);
 }
 
 // ------------------------------------------------------------ harness
@@ -188,7 +188,11 @@ let sent;
 // handler to the buttons it drew, as the browser's fresh list would have.
 let plusButton;
 
+// showFlash() starts a timer that clears the message one or two seconds later.
+// Each test here runs on fake timers and drops them in afterEach, so that timer
+// never outlives the test.
 beforeEach(() => {
+    jest.useFakeTimers();
     approvalDetails = null;
     sent = [];
     mockNode.broadcast = [];
@@ -239,6 +243,7 @@ beforeEach(() => {
 });
 
 afterEach(() => {
+    jest.useRealTimers();
     jest.restoreAllMocks();
 });
 

tests/approvalAmount.test.js

@@ -90,9 +90,11 @@ beforeEach(() => {
 });
 
 describe("resolveTokenDecimals", () => {
+    // The bundled list is read only for a token on Ethereum Mainnet.
     test("prefers the bundled list", () => {
         state.trackedTokens = [{ address: USDC, symbol: "USDC", decimals: 2 }];
-        expect(resolveTokenDecimals(USDC, state)).toBe(6);
+        const sources = { chainId: "0x1", trackedTokens: state.trackedTokens };
+        expect(resolveTokenDecimals(USDC, sources)).toBe(6);
     });
 
     test("reads a token the user tracks", () => {
@@ -124,7 +126,8 @@ describe("resolveTokenDecimals", () => {
     // answers 0 is used rather than fallen past like the unusable entry above.
     test("uses a bundled scale of zero", () => {
         state.trackedTokens = [{ address: SLP, symbol: "SLP", decimals: 18 }];
-        expect(resolveTokenDecimals(SLP, state)).toBe(0);
+        const sources = { chainId: "0x1", trackedTokens: state.trackedTokens };
+        expect(resolveTokenDecimals(SLP, sources)).toBe(0);
     });
 
     test("uses a tracked scale of zero", () => {

tests/approvalBundledListSepolia.test.js

@@ -0,0 +1,169 @@
+// The approval screen for a site's Sepolia transfer of the contract at USDC's
+// mainnet address, while Sepolia is active.
+//
+// The bundled token list holds Ethereum Mainnet contracts. The contract at the
+// same address on Sepolia is another token, but the screen named it USDC and
+// scaled its amount at USDC's decimals
+// (https://git.eeqj.de/sneak/AutistMask/issues/632). The bundled list now names
+// a token only on Ethereum Mainnet. The same screen for a mainnet transfer of
+// USDC, while Sepolia is active, still names USDC.
+//
+// Driven through the real approval screen, against the minimal DOM stub
+// tests/approvalTokenNetwork.test.js uses.
+
+globalThis.chrome = {
+    storage: { local: { get: async () => ({}), set: async () => {} } },
+};
+
+const { Interface } = require("ethers");
+const { state } = require("../src/shared/state");
+const { NETWORKS } = require("../src/shared/networks");
+const approval = require("../src/popup/views/approval");
+
+const FROM = "0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266";
+const RECIPIENT = "0x711e691962E5c054b78071C789A0C8CE657377aD";
+// USDC's address on Ethereum Mainnet, where the bundled list names it.
+const USDC = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48";
+
+// FROM sends 1234500000 base units to RECIPIENT.
+const TRANSFER_DATA = new Interface([
+    "function transfer(address to, uint256 amount)",
+]).encodeFunctionData("transfer", [RECIPIENT, 1234500000n]);
+
+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);
+}
+
+// One line of the decoded details: its label and what is drawn under it.
+function decodedLine(label) {
+    return node("approve-tx-decoded-details")
+        .innerHTML.split('<div class="mb-2">')
+        .find((line) =>
+            line.startsWith(`<div class="text-muted">${label}</div>`),
+        );
+}
+
+// Open the approval screen, with Sepolia active, for the site's transaction
+// sending TRANSFER_DATA to the contract at USDC's address on the network with
+// chain id `chainId`.
+async function showTransfer(chainId) {
+    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: "0x30d40",
+                    maxPriorityFeePerGas: "0x3b9aca00",
+                    maxFeePerGas: "0x77359400",
+                    to: USDC,
+                    value: "0x0",
+                    data: TRANSFER_DATA,
+                    accessList: [],
+                },
+            });
+        },
+    };
+    state.networkId = "sepolia";
+    state.trackedTokens = [];
+    state.networkTrackedTokens = {};
+    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", tokenBalances: [] },
+            ],
+        },
+    ];
+    state.currentView = null;
+    approval.init({});
+    await approval.show(1);
+}
+
+test("names no token, and states the amount in base units", async () => {
+    await showTransfer(NETWORKS.sepolia.chainId);
+    expect(state.currentView).toBe("approve-tx");
+    expect(node("approve-tx-to").innerHTML).not.toContain("USDC");
+    expect(decodedLine("Token")).toContain(
+        '<div class="font-bold">Unknown token</div>',
+    );
+    expect(decodedLine("Amount")).toContain(
+        '<div class="font-bold">1234500000 base units (decimals unknown)</div>',
+    );
+});
+
+// A transaction is named for its own network, not the active one.
+test("a mainnet transfer of USDC is still named and scaled as USDC", async () => {
+    await showTransfer(NETWORKS.mainnet.chainId);
+    expect(state.currentView).toBe("approve-tx");
+    expect(decodedLine("Token")).toContain('<div class="font-bold">USDC</div>');
+    expect(decodedLine("Amount")).toContain(
+        '<div class="font-bold">1234.5000 USDC</div>',
+    );
+});

tests/backgroundApproval.test.js

@@ -537,7 +537,18 @@ async function settleIncludingRejections() {
     await new Promise((resolve) => setImmediate(resolve));
 }
 
+// While an approval is pending, the background starts a 20-second timer to
+// keep itself running. The timer is stubbed and never starts, so no test in
+// this file leaves it running.
+let keepRunningTimer;
+beforeEach(() => {
+    keepRunningTimer = jest
+        .spyOn(global, "setInterval")
+        .mockImplementation(() => 1);
+});
+
 afterEach(() => {
+    keepRunningTimer.mockRestore();
     delete global.chrome;
     jest.resetModules();
 });
@@ -1883,18 +1894,6 @@ describe("a closed approval window leaves the request pending", () => {
         return bg.actionPopups[bg.actionPopups.length - 1];
     }
 
-    // The timer that keeps the worker running while an approval is pending is
-    // stubbed, so no test here leaves that timer running when it ends.
-    let keepRunningTimer;
-    beforeEach(() => {
-        keepRunningTimer = jest
-            .spyOn(global, "setInterval")
-            .mockImplementation(() => 1);
-    });
-    afterEach(() => {
-        keepRunningTimer.mockRestore();
-    });
-
     test("the toolbar popup opens a closed transaction approval, and approving it there sends", async () => {
         const bg = loadBackground();
         const pending = bg.requestTx();

tests/backgroundStateIsolation.test.js

@@ -103,7 +103,18 @@ function deferred() {
     return { promise, resolve };
 }
 
+// While an approval is pending, the background starts a 20-second timer to
+// keep itself running. The timer is stubbed and never starts, so no test in
+// this file leaves it running.
+let keepRunningTimer;
+beforeEach(() => {
+    keepRunningTimer = jest
+        .spyOn(global, "setInterval")
+        .mockImplementation(() => 1);
+});
+
 afterEach(() => {
+    keepRunningTimer.mockRestore();
     delete global.chrome;
 });
 

tests/balanceRefreshNetworkSwitch.test.js

@@ -6,6 +6,10 @@
 // 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.
+//
+// The last test covers a balance refresh by the background that is saved while
+// a switch in Settings waits for the lock
+// (https://git.eeqj.de/sneak/AutistMask/issues/653).
 
 const {
     bootPopup,
@@ -41,6 +45,7 @@ async function holdRefresh(page) {
                 holders: null,
             },
         ];
+        return [];
     });
     const ticking = page.tick();
     await page.settle();
@@ -159,3 +164,50 @@ test("a refresh that returns after the background switched the network writes no
 
     expectNothingStored(page);
 });
+
+// The background's refresh saves Ethereum Mainnet's balances while the switch
+// in Settings waits for the lock. This page last saved a balance of "0" and no
+// token balances, the values that the switch sets.
+test("a background refresh saved while a switch in Settings waits for the lock leaves none of its balances stored", async () => {
+    const profile = unversionedValidProfile();
+    profile.wallets[0].addresses[0].balance = "0";
+    const page = await bootPopup(profile);
+    expect(page.pageErrors).toEqual([]);
+    const background = require("../src/background/state");
+    await page.click("btn-settings");
+
+    // The background takes the lock first and holds it until the test calls
+    // `letGo()`. It then saves balances as backgroundRefresh() in
+    // src/background/index.js does.
+    let letGo;
+    const refreshSave = background.updateState(async (fresh) => {
+        await new Promise((resolve) => {
+            letGo = resolve;
+        });
+        fresh.wallets[0].addresses[0].balance = "7.0";
+        fresh.wallets[0].addresses[0].tokenBalances = [
+            {
+                address: TOKEN_ADDRESS,
+                name: "Test Token",
+                symbol: "TST",
+                decimals: 18,
+                balance: "5.0",
+                holders: null,
+            },
+        ];
+        fresh.lastBalanceRefresh = Date.now();
+    });
+    await page.settle();
+
+    const select = page.node("settings-network");
+    select.value = "sepolia";
+    const switching = Promise.all(select.listeners.change.map((fn) => fn()));
+    await page.settle();
+
+    letGo();
+    await refreshSave;
+    await switching;
+    await page.settle();
+
+    expectNothingStored(page);
+});

tests/blockscoutEtherscanSettings.test.js

@@ -720,6 +720,7 @@ describe("the popup", () => {
                 tokenRow(TRACKED, "TRK"),
                 tokenRow(UNTRACKED, "TST"),
             ];
+            return [];
         });
         const ticking = page.tick();
         await page.settle();
@@ -764,6 +765,7 @@ describe("the popup", () => {
                 addr.tokenBalances = after
                     ? [tokenRow(TRACKED, "TRK"), tokenRow(UNTRACKED, "TST")]
                     : [tokenRow(TRACKED, "TRK")];
+                return [];
             });
 
             anotherPageSaves(page, { useBlockscout: after });

tests/bundledListScreens.test.js

@@ -0,0 +1,81 @@
+// The token screen, the Send screen and the confirmation screen for the
+// contract at USDC's mainnet address. No address holds it and the user does
+// not track it, so only the bundled token list can name it.
+//
+// The bundled token list holds Ethereum Mainnet contracts, so these screens
+// name the token from it on Ethereum Mainnet only
+// (https://git.eeqj.de/sneak/AutistMask/issues/632). Driven through the real
+// popup over a stored profile.
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+} = require("./support/popupBoot");
+
+const USDC = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48";
+const RECIPIENT = "0x711e691962E5c054b78071C789A0C8CE657377aD";
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+// The popup reopened onto AddressToken for USDC's address, on `networkId`.
+function bootOnToken(networkId) {
+    return bootPopup(
+        unversionedValidProfile({
+            networkId,
+            currentView: "address-token",
+            viewStack: ["main", "address"],
+            selectedWallet: 0,
+            selectedAddress: 0,
+            selectedToken: USDC,
+        }),
+    );
+}
+
+// AddressToken's Send, then Review for 1 token to RECIPIENT.
+async function reviewSend(boot) {
+    await boot.click("btn-address-token-send");
+    expect(boot.visibleViews()).toEqual(["send"]);
+    boot.node("send-to").value = RECIPIENT;
+    boot.node("send-amount").value = "1";
+    await boot.click("btn-send-review");
+    expect(boot.visibleViews()).toEqual(["confirm-tx"]);
+}
+
+describe("on Ethereum Mainnet, the bundled list names the token", () => {
+    test("on the token screen", async () => {
+        const boot = await bootOnToken("mainnet");
+        expect(boot.visibleViews()).toEqual(["address-token"]);
+        expect(boot.text("address-token-title")).toContain("USDC");
+        const info = boot.node("address-token-contract-info").innerHTML;
+        expect(info).toContain(
+            '<span class="text-muted">Decimals:</span> 6</div>',
+        );
+    });
+
+    test("on the Send screen and the confirmation screen", async () => {
+        const boot = await bootOnToken("mainnet");
+        await reviewSend(boot);
+        expect(boot.text("send-balance")).toContain("USDC");
+        expect(boot.text("confirm-amount")).toContain("USDC");
+    });
+});
+
+describe("with Sepolia active, the bundled list does not name the token", () => {
+    test("on the token screen", async () => {
+        const boot = await bootOnToken("sepolia");
+        expect(boot.visibleViews()).toEqual(["address-token"]);
+        expect(boot.text("address-token-title")).not.toContain("USDC");
+        const info = boot.node("address-token-contract-info").innerHTML;
+        expect(info).not.toContain("Decimals:");
+    });
+
+    test("on the Send screen and the confirmation screen", async () => {
+        const boot = await bootOnToken("sepolia");
+        await reviewSend(boot);
+        expect(boot.text("send-balance")).not.toContain("USDC");
+        expect(boot.text("confirm-amount")).not.toContain("USDC");
+    });
+});

tests/chainSwitchGate.test.js

@@ -56,7 +56,18 @@ async function settle() {
     for (let i = 0; i < 50; i++) await Promise.resolve();
 }
 
+// While an approval is pending, the background starts a 20-second timer to
+// keep itself running. The timer is stubbed and never starts, so no test in
+// this file leaves it running.
+let keepRunningTimer;
+beforeEach(() => {
+    keepRunningTimer = jest
+        .spyOn(global, "setInterval")
+        .mockImplementation(() => 1);
+});
+
 afterEach(() => {
+    keepRunningTimer.mockRestore();
     delete global.chrome;
 });
 

tests/coldWorkerChainSwitch.test.js

@@ -64,7 +64,18 @@ async function settle() {
     for (let i = 0; i < 50; i++) await Promise.resolve();
 }
 
+// While an approval is pending, the background starts a 20-second timer to
+// keep itself running. The timer is stubbed and never starts, so no test in
+// this file leaves it running.
+let keepRunningTimer;
+beforeEach(() => {
+    keepRunningTimer = jest
+        .spyOn(global, "setInterval")
+        .mockImplementation(() => 1);
+});
+
 afterEach(() => {
+    keepRunningTimer.mockRestore();
     delete global.chrome;
 });
 

tests/coldWorkerSendTransaction.test.js

@@ -76,7 +76,18 @@ async function settle() {
     for (let i = 0; i < 60; i++) await Promise.resolve();
 }
 
+// While an approval is pending, the background starts a 20-second timer to
+// keep itself running. The timer is stubbed and never starts, so no test in
+// this file leaves it running.
+let keepRunningTimer;
+beforeEach(() => {
+    keepRunningTimer = jest
+        .spyOn(global, "setInterval")
+        .mockImplementation(() => 1);
+});
+
 afterEach(() => {
+    keepRunningTimer.mockRestore();
     delete global.chrome;
 });
 

tests/connectedSitesWorkerRestart.test.js

@@ -57,7 +57,18 @@ async function settle() {
     for (let i = 0; i < 50; i++) await Promise.resolve();
 }
 
+// While an approval is pending, the background starts a 20-second timer to
+// keep itself running. The timer is stubbed and never starts, so no test in
+// this file leaves it running.
+let keepRunningTimer;
+beforeEach(() => {
+    keepRunningTimer = jest
+        .spyOn(global, "setInterval")
+        .mockImplementation(() => 1);
+});
+
 afterEach(() => {
+    keepRunningTimer.mockRestore();
     delete global.chrome;
     jest.resetModules();
 });

tests/deleteWalletLostPassword.test.js

@@ -102,6 +102,17 @@ function makeDocument() {
 
 // ------------------------------------------------------------ harness
 
+// showFlash() starts a timer that clears the message two seconds later. Each
+// test here runs on fake timers and drops them in afterEach, so that timer
+// never outlives the test.
+beforeEach(() => {
+    jest.useFakeTimers();
+});
+
+afterEach(() => {
+    jest.useRealTimers();
+});
+
 function wallet(name, secret, addresses) {
     return {
         type: "hd",

tests/e2e/network.js

@@ -253,8 +253,8 @@ const SELECTOR_NAME = "0x06fdde03";
 const SELECTOR_BALANCE_OF = "0x70a08231";
 const SELECTOR_LATEST_ROUND_DATA = "0xfeaf968c";
 
-// A price feed's latestRoundData() is answered on any contract with five zero
-// words. That is a round with a price of zero, which the wallet counts as no
+// On any contract, a latestRoundData() call is answered with five zero words.
+// That is a round with a price of zero, which the wallet counts as no
 // price. So no screen shows a USD value beside the amounts the tests compare.
 //
 // Every other eth_call answers with a zero word except decimals(), symbol(),

tests/e2e/run.js

@@ -969,7 +969,8 @@ 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 },

tests/fabricatedDecimals.test.js

@@ -111,13 +111,15 @@ function respondWith(items) {
 }
 
 // Fetch and place the result exactly where refreshBalances() places it, so the
-// approval screens read what a real refresh would have left on state.
+// approval screens read what a real refresh on Ethereum Mainnet would have
+// left on state.
 async function fetchOnto(items, trackedTokens = []) {
     respondWith(items);
     const balances = await fetchTokenBalances(
         HOLDER,
         BLOCKSCOUT,
         trackedTokens,
+        "0x1",
     );
     state.trackedTokens = trackedTokens;
     state.wallets = [

tests/firstWalletRefresh.test.js

@@ -48,6 +48,7 @@ async function boot(stored) {
         for (const wallet of wallets) {
             for (const addr of wallet.addresses) addr.balance = chainBalance;
         }
+        return [];
     });
     return { page, refreshBalances };
 }

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/historyAfterNetworkSwitch.test.js

@@ -0,0 +1,500 @@
+// Home, AddressDetail and AddressToken drop a transaction history answer that
+// lands after a network switch. A dropped answer draws no rows and saves no
+// fraud contracts (https://git.eeqj.de/sneak/AutistMask/issues/657).
+//
+// Most tests hold the history request open, switch the network or what the
+// screen shows, and then let the answer land. The views run against a minimal
+// DOM stub, as in tests/transactionListCancelled.test.js, and over
+// tests/support/storageStub.js.
+
+const { makeStorageStub } = require("./support/storageStub");
+const { STATE_SCHEMA_VERSION } = require("../src/shared/stateSchema");
+
+jest.mock("../src/shared/transactions", () => ({
+    ...jest.requireActual("../src/shared/transactions"),
+    fetchRecentTransactions: jest.fn(async () => []),
+}));
+jest.mock("../src/shared/ens", () => ({
+    resolveEnsNames: jest.fn(async () => new Map()),
+}));
+
+const { fetchRecentTransactions } = require("../src/shared/transactions");
+const { resolveEnsNames } = require("../src/shared/ens");
+const { state, loadState } = require("../src/shared/state");
+const { onChainSwitch } = require("../src/shared/chainSwitch");
+const { applyChainSwitchFields } = require("../src/shared/chainSwitchFields");
+const { storedNetworkIs } = require("../src/shared/storedSettings");
+const home = require("../src/popup/views/home");
+const addressDetail = require("../src/popup/views/addressDetail");
+const addressToken = require("../src/popup/views/addressToken");
+
+const ADDRESS = "0x1111111111111111111111111111111111111111";
+const OTHER_ADDRESS = "0x2222222222222222222222222222222222222222";
+const RECIPIENT = "0x66133E8ea0f5D1d612D2502a968757D1048c214a";
+// A contract that sends a token claiming USDT's symbol. Spotting the spoof
+// adds this contract to the fraud contracts.
+const SPOOF_CONTRACT = "0x3333333333333333333333333333333333333333";
+const TOKEN = "0x6B175474E89094C44Da98b954EedeAC495271d0F";
+
+// A profile on Ethereum Mainnet with two addresses, "Use Blockscout" on and no
+// fraud contracts.
+function profile() {
+    return {
+        schemaVersion: STATE_SCHEMA_VERSION,
+        hasWallet: true,
+        wallets: [
+            {
+                type: "hd",
+                name: "Main",
+                xpub: "xpub-main",
+                encryptedSecret: "encrypted-secret",
+                nextIndex: 2,
+                addresses: [
+                    { address: ADDRESS, balance: "1.0", tokenBalances: [] },
+                    {
+                        address: OTHER_ADDRESS,
+                        balance: "0.0",
+                        tokenBalances: [],
+                    },
+                ],
+            },
+        ],
+        activeAddress: ADDRESS,
+        networkId: "mainnet",
+        rpcUrl: "https://ethereum-rpc.publicnode.com",
+        blockscoutUrl: "https://eth.blockscout.com/api/v2",
+        useBlockscout: true,
+        fraudContracts: [],
+    };
+}
+
+// What Blockscout answers for ADDRESS on Ethereum Mainnet:
+//
+// - a transfer of ETH from ADDRESS;
+// - a transfer of the fake USDT from SPOOF_CONTRACT.
+function history() {
+    return [
+        {
+            hash: "0x85215772ed26ea8b39c2b3b18779030487efbe0b5fd7e882592b2f62b837be84",
+            blockNumber: 2,
+            from: ADDRESS,
+            to: RECIPIENT,
+            value: "1.0000",
+            exactValue: "1.0",
+            rawAmount: "1000000000000000000",
+            rawUnit: "wei",
+            symbol: "ETH",
+            timestamp: 1790000000,
+            isError: false,
+            directionLabel: "Sent",
+            direction: "sent",
+            contractAddress: null,
+            chainId: "0x1",
+        },
+        {
+            hash: "0x0d6a6e0a0d1b7d4c3b2a19087f6e5d4c3b2a19087f6e5d4c3b2a19087f6e5d4c",
+            blockNumber: 1,
+            from: SPOOF_CONTRACT,
+            to: ADDRESS,
+            value: "100.0000",
+            exactValue: "100.0",
+            rawAmount: "100000000",
+            rawUnit: "base units",
+            symbol: "USDT",
+            timestamp: 1790000000,
+            isError: false,
+            directionLabel: "Received",
+            direction: "received",
+            contractAddress: SPOOF_CONTRACT,
+            chainId: "0x1",
+        },
+    ];
+}
+
+// The next history request waits until the returned function is called, and
+// then answers with `answer`.
+function holdHistory(answer = history()) {
+    let land;
+    fetchRecentTransactions.mockImplementationOnce(
+        () =>
+            new Promise((resolve) => {
+                land = () => resolve(answer);
+            }),
+    );
+    return () => land();
+}
+
+// The next history request waits until the returned function is called, and
+// then fails.
+function holdFailure() {
+    let fail;
+    fetchRecentTransactions.mockImplementationOnce(
+        () =>
+            new Promise((resolve, reject) => {
+                fail = () => reject(new Error("Blockscout is down"));
+            }),
+    );
+    return () => fail();
+}
+
+// Another write holds the lock until the returned function is called. Every
+// save waits until then.
+function holdLock() {
+    let release;
+    const held = navigator.locks.request(
+        "autistmask",
+        () =>
+            new Promise((resolve) => {
+                release = resolve;
+            }),
+    );
+    return async () => {
+        release();
+        await held;
+    };
+}
+
+function makeElement(id) {
+    const el = {
+        id,
+        textContent: "",
+        value: "",
+        innerHTML: "",
+        style: {},
+        dataset: {},
+        classList: {
+            add: () => {},
+            remove: () => {},
+            contains: () => false,
+            toggle: () => false,
+        },
+        addEventListener: () => {},
+        querySelectorAll: () => [],
+        appendChild: () => {},
+    };
+    // Views reach for .parentElement to hide whole sections.
+    Object.defineProperty(el, "parentElement", {
+        get: () => node(id + "-parent"),
+    });
+    return el;
+}
+
+function makeDocument() {
+    const els = new Map();
+    return {
+        getElementById(id) {
+            // The debug banner is created on demand by helpers.js; absent
+            // is the state a non-debug, non-testnet popup is in.
+            if (id === "debug-banner") return null;
+            if (!els.has(id)) els.set(id, makeElement(id));
+            return els.get(id);
+        },
+        createElement: () => makeElement("created"),
+        addEventListener: () => {},
+        body: { prepend: () => {} },
+    };
+}
+
+function node(id) {
+    return globalThis.document.getElementById(id);
+}
+
+// Lets every promise that is not held open settle.
+function settle() {
+    return new Promise((resolve) => setTimeout(resolve, 0));
+}
+
+let storage;
+
+beforeEach(async () => {
+    storage = makeStorageStub({ autistmask: profile() });
+    globalThis.chrome = {
+        storage: { local: storage.local, onChanged: storage.onChanged },
+    };
+    globalThis.document = makeDocument();
+    globalThis.window = { location: { search: "" } };
+    await loadState();
+    state.viewStack = [];
+    state.selectedWallet = 0;
+    state.selectedAddress = 0;
+    state.selectedToken = "ETH";
+    const ctx = { pageClosed: new AbortController().signal };
+    addressDetail.init(ctx);
+    addressToken.init(ctx);
+});
+
+afterEach(() => {
+    delete globalThis.chrome;
+    delete globalThis.document;
+    delete globalThis.window;
+});
+
+const HOME = {
+    name: "Home",
+    listId: "home-tx-list",
+    open: () => home.render({ pageClosed: new AbortController().signal }),
+};
+const ADDRESS_DETAIL = {
+    name: "AddressDetail",
+    listId: "tx-list",
+    open: () => addressDetail.show(),
+};
+const ADDRESS_TOKEN = {
+    name: "AddressToken",
+    listId: "address-token-tx-list",
+    open: () => addressToken.show(),
+};
+
+// Three ways a test switches the network:
+//
+// - made in Settings: the page and storage have both switched;
+// - saved elsewhere: storage has switched and the page has not;
+// - not yet stored: the page has switched and storage has not.
+const SWITCHES = [
+    {
+        how: "made in Settings",
+        to: (networkId) => onChainSwitch(networkId),
+    },
+    {
+        // Another page or the background stored the switch, and this page has
+        // not followed it yet.
+        how: "saved elsewhere",
+        to: async (networkId) => {
+            const record = storage.read("autistmask");
+            applyChainSwitchFields(record, networkId);
+            storage.write("autistmask", record);
+        },
+    },
+    {
+        // The switch's own save has changed the page and has not yet written
+        // storage.
+        how: "not yet stored",
+        to: async (networkId) => {
+            applyChainSwitchFields(state, networkId);
+        },
+    },
+];
+
+// The list still shows `before`, and neither the page nor storage holds a
+// fraud contract.
+function expectNothingAdded(screen, before) {
+    expect(node(screen.listId).innerHTML).toBe(before);
+    expect(state.fraudContracts).toEqual([]);
+    expect(storage.read("autistmask").fraudContracts).toEqual([]);
+}
+
+describe.each([HOME, ADDRESS_DETAIL, ADDRESS_TOKEN])("$name", (screen) => {
+    test("an answer that lands on the same network is drawn and saved", async () => {
+        const land = holdHistory();
+        screen.open();
+        land();
+        await settle();
+
+        expect(node(screen.listId).innerHTML).toContain("tx-row");
+        expect(state.fraudContracts).toEqual([SPOOF_CONTRACT]);
+        expect(storage.read("autistmask").fraudContracts).toEqual([
+            SPOOF_CONTRACT,
+        ]);
+    });
+
+    test.each(SWITCHES)(
+        "an answer that lands after a switch $how adds nothing",
+        async ({ to }) => {
+            const land = holdHistory();
+            screen.open();
+            await settle();
+            const before = node(screen.listId).innerHTML;
+            await to("sepolia");
+            land();
+            await settle();
+
+            expectNothingAdded(screen, before);
+        },
+    );
+
+    // The answer is the transfer of ETH alone, which adds no fraud contract.
+    // Nothing is saved, so only the check before the save can drop the answer.
+    test.each(SWITCHES)(
+        "an answer without a fraud contract that lands after a switch $how adds nothing",
+        async ({ to }) => {
+            const land = holdHistory(history().slice(0, 1));
+            screen.open();
+            await settle();
+            const before = node(screen.listId).innerHTML;
+            await to("sepolia");
+            land();
+            await settle();
+
+            expectNothingAdded(screen, before);
+        },
+    );
+
+    test.each(SWITCHES)(
+        "a request that fails after a switch $how shows no message",
+        async ({ to }) => {
+            const fail = holdFailure();
+            screen.open();
+            await settle();
+            const before = node(screen.listId).innerHTML;
+            await to("sepolia");
+            fail();
+            await settle();
+
+            expect(node(screen.listId).innerHTML).toBe(before);
+        },
+    );
+
+    // The user picks Sepolia in Settings while another write holds the lock.
+    // The answer lands, and its save waits behind the switch.
+    test("an answer whose save waits behind a switch made in Settings adds nothing", async () => {
+        const land = holdHistory();
+        screen.open();
+        const before = node(screen.listId).innerHTML;
+        const releaseLock = holdLock();
+        const switching = onChainSwitch("sepolia");
+        land();
+        await settle();
+        await releaseLock();
+        await switching;
+        await settle();
+
+        expectNothingAdded(screen, before);
+    });
+
+    // The answer lands and its save waits for the lock. Another page or the
+    // background then stores a switch.
+    test("an answer whose save waits while a switch is saved elsewhere adds nothing", async () => {
+        const land = holdHistory();
+        screen.open();
+        const before = node(screen.listId).innerHTML;
+        const releaseLock = holdLock();
+        land();
+        await settle();
+        const record = storage.read("autistmask");
+        applyChainSwitchFields(record, "sepolia");
+        storage.write("autistmask", record);
+        await releaseLock();
+        await settle();
+
+        expectNothingAdded(screen, before);
+    });
+
+    // The answer lands and its save waits for the lock. The page then switches,
+    // and storage has not.
+    test("an answer whose save waits while the page switches adds nothing", async () => {
+        const land = holdHistory();
+        screen.open();
+        const before = node(screen.listId).innerHTML;
+        const releaseLock = holdLock();
+        land();
+        await settle();
+        applyChainSwitchFields(state, "sepolia");
+        await releaseLock();
+        await settle();
+
+        expectNothingAdded(screen, before);
+    });
+
+    test("a request that fails after a switch leaves the new network's rows", async () => {
+        const fail = holdFailure();
+        screen.open();
+        await onChainSwitch("sepolia");
+        fetchRecentTransactions.mockImplementationOnce(async () => history());
+        screen.open();
+        await settle();
+        const drawn = node(screen.listId).innerHTML;
+        fail();
+        await settle();
+
+        expect(drawn).toContain("tx-row");
+        expect(node(screen.listId).innerHTML).toBe(drawn);
+    });
+});
+
+describe.each([ADDRESS_DETAIL, ADDRESS_TOKEN])("$name", (screen) => {
+    test("an answer that lands once the screen shows another address adds nothing", async () => {
+        const land = holdHistory();
+        screen.open();
+        state.selectedAddress = 1;
+        screen.open();
+        await settle();
+        const before = node(screen.listId).innerHTML;
+        land();
+        await settle();
+
+        expectNothingAdded(screen, before);
+    });
+
+    test("a request that fails once the screen shows another address shows no message", async () => {
+        const fail = holdFailure();
+        screen.open();
+        state.selectedAddress = 1;
+        screen.open();
+        await settle();
+        const before = node(screen.listId).innerHTML;
+        fail();
+        await settle();
+
+        expect(node(screen.listId).innerHTML).toBe(before);
+    });
+
+    // The answer is the transfer of ETH alone, which adds no fraud contract.
+    // Nothing is saved, so only the check after the name lookup can drop the
+    // answer.
+    test("an answer whose name lookup lands after a switch adds nothing", async () => {
+        let landNames;
+        resolveEnsNames.mockImplementationOnce(
+            () =>
+                new Promise((resolve) => {
+                    landNames = () => resolve(new Map());
+                }),
+        );
+        fetchRecentTransactions.mockImplementationOnce(async () =>
+            history().slice(0, 1),
+        );
+        screen.open();
+        await settle();
+        const before = node(screen.listId).innerHTML;
+        await onChainSwitch("sepolia");
+        landNames();
+        await settle();
+
+        expectNothingAdded(screen, before);
+    });
+});
+
+test("AddressToken: an answer that lands once the screen shows another token adds nothing", async () => {
+    const land = holdHistory();
+    addressToken.show();
+    state.selectedToken = TOKEN;
+    addressToken.show();
+    await settle();
+    const before = node(ADDRESS_TOKEN.listId).innerHTML;
+    land();
+    await settle();
+
+    expectNothingAdded(ADDRESS_TOKEN, before);
+});
+
+test("AddressToken: a request that fails once the screen shows another token shows no message", async () => {
+    const fail = holdFailure();
+    addressToken.show();
+    state.selectedToken = TOKEN;
+    addressToken.show();
+    await settle();
+    const before = node(ADDRESS_TOKEN.listId).innerHTML;
+    fail();
+    await settle();
+
+    expect(node(ADDRESS_TOKEN.listId).innerHTML).toBe(before);
+});
+
+test("storedNetworkIs(): a failed read counts as no", async () => {
+    globalThis.chrome.storage.local = {
+        get: async () => {
+            throw new Error("storage is down");
+        },
+    };
+
+    await expect(storedNetworkIs("mainnet")).resolves.toBe(false);
+});

tests/holders.test.js

@@ -192,7 +192,13 @@ describe("the balance-list spam gate", () => {
                 },
             }),
         ]);
-        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
+        // On Ethereum Mainnet, the only network the known-token list covers.
+        const balances = await fetchTokenBalances(
+            HOLDER,
+            BLOCKSCOUT,
+            [],
+            "0x1",
+        );
         expect(balances).toHaveLength(1);
         expect(balances[0].holders).toBeNull();
     });

tests/popupFollowsNetworkSwitch.test.js

@@ -253,6 +253,271 @@ test("a switch back in Settings after a follow whose write failed is stored", as
     expect(told.at(-1).chainId).toBe(NETWORKS.mainnet.chainId);
 });
 
+// The user saves an endpoint URL in Settings on Ethereum Mainnet. Before the
+// URL is stored, the background saves a switch to Sepolia. Another write holds
+// the lock, so the popup's follow of that switch and the URL's save both wait
+// for the lock. Either may take it first. The URL is stored for neither
+// network. The flash message says that the network changed.
+test.each([
+    { button: "btn-save-rpc", field: "settings-rpc", first: "follow" },
+    { button: "btn-save-rpc", field: "settings-rpc", first: "save" },
+    {
+        button: "btn-save-blockscout",
+        field: "settings-blockscout",
+        first: "follow",
+    },
+    {
+        button: "btn-save-blockscout",
+        field: "settings-blockscout",
+        first: "save",
+    },
+])(
+    "$button saves nothing when the network changes before the URL is stored ($first first)",
+    async ({ button, field, first }) => {
+        const page = await bootOnAddress();
+        await page.click("btn-settings");
+        // This answer passes both endpoint checks. The RPC check reads
+        // Ethereum Mainnet's chain id from it. The Blockscout check reads `ok`.
+        globalThis.fetch.mockResolvedValue({
+            ok: true,
+            json: async () => ({ result: NETWORKS.mainnet.chainId }),
+        });
+        const url = "https://own-node.example.invalid";
+
+        let releaseLock;
+        const lockHeld = navigator.locks.request(
+            "autistmask",
+            () =>
+                new Promise((resolve) => {
+                    releaseLock = resolve;
+                }),
+        );
+        // The click handler runs until its save waits for the lock.
+        const tapSave = async () => {
+            page.node(field).value = url;
+            const saving = page.node(button).listeners.click.map((fn) => fn());
+            await page.settle();
+            return saving;
+        };
+        let saving;
+        if (first === "save") saving = await tapSave();
+        await backgroundSwitch(page, "sepolia");
+        if (first === "follow") saving = await tapSave();
+        releaseLock();
+        await lockHeld;
+        await Promise.all(saving);
+        await page.settle();
+
+        const { state } = require("../src/shared/state");
+        expect(state.networkId).toBe("sepolia");
+        expect(JSON.stringify(page.storage.read("autistmask"))).not.toContain(
+            url,
+        );
+        expect(page.text("flash-msg")).toBe(
+            "The URL was not saved because the network changed.",
+        );
+    },
+);
+
+// The popup's follow of the background's switch to Sepolia has set `state` to
+// Sepolia. The follow's write has not returned yet, so Settings still shows
+// Ethereum Mainnet. The user taps "Save" there. The URL is for Ethereum
+// Mainnet, so the save stores the URL for neither network.
+test.each([
+    { button: "btn-save-rpc", field: "settings-rpc" },
+    { button: "btn-save-blockscout", field: "settings-blockscout" },
+])(
+    "$button saves nothing when tapped while the follow's write waits",
+    async ({ button, field }) => {
+        const page = await bootOnAddress();
+        await page.click("btn-settings");
+        // This answer passes both endpoint checks on Ethereum Mainnet.
+        globalThis.fetch.mockResolvedValue({
+            ok: true,
+            json: async () => ({ result: NETWORKS.mainnet.chainId }),
+        });
+        const url = "https://own-node.example.invalid";
+
+        const { set } = page.storage.local;
+        const write = set.getMockImplementation();
+        let releaseWrite;
+        const writeHeld = new Promise((resolve) => {
+            releaseWrite = resolve;
+        });
+        // The background's write lands; the next, the follow's, waits.
+        set.mockImplementationOnce(write).mockImplementationOnce(
+            async (items) => {
+                await writeHeld;
+                await write(items);
+            },
+        );
+        await backgroundSwitch(page, "sepolia");
+        const { state } = require("../src/shared/state");
+        expect(state.networkId).toBe("sepolia");
+        expect(page.value("settings-network")).toBe("mainnet");
+
+        page.node(field).value = url;
+        const saving = page.node(button).listeners.click.map((fn) => fn());
+        await page.settle();
+        releaseWrite();
+        await Promise.all(saving);
+        await page.settle();
+
+        expect(JSON.stringify(page.storage.read("autistmask"))).not.toContain(
+            url,
+        );
+        expect(page.text("flash-msg")).toBe(
+            "The URL was not saved because the network changed.",
+        );
+    },
+);
+
+// The user taps the RPC "Save" on Ethereum Mainnet. While the check waits for
+// the node's answer, the popup follows the background's switch to Sepolia. The
+// node answers with Sepolia's chain id. So the check refuses the node for
+// Ethereum Mainnet, and nothing is stored.
+test("the RPC check compares the answer with the network at the tap", async () => {
+    const page = await bootOnAddress();
+    await page.click("btn-settings");
+    let answer;
+    globalThis.fetch.mockReturnValue(
+        new Promise((resolve) => {
+            answer = resolve;
+        }),
+    );
+    const url = "https://sepolia-node.example.invalid";
+
+    page.node("settings-rpc").value = url;
+    const saving = page.node("btn-save-rpc").listeners.click.map((fn) => fn());
+    await page.settle();
+    await backgroundSwitch(page, "sepolia");
+    const { state } = require("../src/shared/state");
+    expect(state.networkId).toBe("sepolia");
+    answer({ json: async () => ({ result: NETWORKS.sepolia.chainId }) });
+    await Promise.all(saving);
+    await page.settle();
+
+    expect(JSON.stringify(page.storage.read("autistmask"))).not.toContain(url);
+    expect(page.text("flash-msg")).toBe(
+        "Wrong network: expected Ethereum Mainnet.",
+    );
+});
+
+// The user taps the Blockscout "Save" on Ethereum Mainnet. While the check
+// waits for Blockscout's answer, the popup follows the background's switch to
+// Sepolia. The URL is for Ethereum Mainnet, so nothing is stored.
+test("the Blockscout save is for the network at the tap", async () => {
+    const page = await bootOnAddress();
+    await page.click("btn-settings");
+    let answer;
+    globalThis.fetch.mockReturnValue(
+        new Promise((resolve) => {
+            answer = resolve;
+        }),
+    );
+    const url = "https://own-explorer.example.invalid/api/v2";
+
+    page.node("settings-blockscout").value = url;
+    const saving = page
+        .node("btn-save-blockscout")
+        .listeners.click.map((fn) => fn());
+    await page.settle();
+    await backgroundSwitch(page, "sepolia");
+    expect(page.value("settings-network")).toBe("sepolia");
+    answer({ ok: true });
+    await Promise.all(saving);
+    await page.settle();
+
+    expect(JSON.stringify(page.storage.read("autistmask"))).not.toContain(url);
+    expect(page.text("flash-msg")).toBe(
+        "The URL was not saved because the network changed.",
+    );
+});
+
+// Settings is open when the network changes to Sepolia. The popup follows the
+// background's switch, or the user picks Sepolia in the network selector. Each
+// "Save" after the switch stores its URL for Sepolia.
+test.each([
+    ["a follow", (page) => backgroundSwitch(page, "sepolia")],
+    [
+        "the network selector",
+        async (page) => {
+            const select = page.node("settings-network");
+            select.value = "sepolia";
+            for (const fn of select.listeners.change) await fn();
+            await page.settle();
+        },
+    ],
+])(
+    "after a switch to Sepolia by %s, Settings saves each URL for Sepolia",
+    async (_how, switchToSepolia) => {
+        const page = await bootOnAddress();
+        await page.click("btn-settings");
+        await switchToSepolia(page);
+        // This answer passes both endpoint checks on Sepolia. The RPC check
+        // reads Sepolia's chain id from it. The Blockscout check reads `ok`.
+        globalThis.fetch.mockResolvedValue({
+            ok: true,
+            json: async () => ({ result: NETWORKS.sepolia.chainId }),
+        });
+        const rpcUrl = "https://own-node.example.invalid";
+        const blockscoutUrl = "https://own-explorer.example.invalid/api/v2";
+
+        page.node("settings-rpc").value = rpcUrl;
+        await page.click("btn-save-rpc");
+        expect(page.text("flash-msg")).toBe("Saved.");
+        page.node("settings-blockscout").value = blockscoutUrl;
+        await page.click("btn-save-blockscout");
+        expect(page.text("flash-msg")).toBe("Saved.");
+
+        const stored = page.storage.read("autistmask");
+        expect(stored.networkId).toBe("sepolia");
+        expect(stored.rpcUrl).toBe(rpcUrl);
+        expect(stored.blockscoutUrl).toBe(blockscoutUrl);
+    },
+);
+
+// The user picks Sepolia in Settings, but the switch's write fails. The page is
+// then on Sepolia, while Settings was last drawn for Ethereum Mainnet. A "Save"
+// after the failed switch stores nothing for either network.
+test.each([
+    { button: "btn-save-rpc", field: "settings-rpc" },
+    { button: "btn-save-blockscout", field: "settings-blockscout" },
+])(
+    "$button saves nothing after a switch in Settings whose write failed",
+    async ({ button, field }) => {
+        const page = await bootOnAddress();
+        await page.click("btn-settings");
+        page.storage.local.set.mockRejectedValueOnce(
+            new Error("quota exceeded"),
+        );
+        const select = page.node("settings-network");
+        select.value = "sepolia";
+        for (const fn of select.listeners.change) {
+            await expect(fn()).rejects.toThrow("quota exceeded");
+        }
+        await page.settle();
+        const { state } = require("../src/shared/state");
+        expect(state.networkId).toBe("sepolia");
+        // This answer passes both endpoint checks on Ethereum Mainnet.
+        globalThis.fetch.mockResolvedValue({
+            ok: true,
+            json: async () => ({ result: NETWORKS.mainnet.chainId }),
+        });
+        const url = "https://own-node.example.invalid";
+
+        page.node(field).value = url;
+        await page.click(button);
+
+        expect(JSON.stringify(page.storage.read("autistmask"))).not.toContain(
+            url,
+        );
+        expect(page.text("flash-msg")).toBe(
+            "The URL was not saved because the network changed.",
+        );
+    },
+);
+
 // 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.

tests/refreshDuringRefresh.test.js

@@ -0,0 +1,157 @@
+// While a refresh runs, a request through ctx is not dropped. One more refresh
+// runs once the running one ends, however many were asked for in that time
+// (https://git.eeqj.de/sneak/AutistMask/issues/581). A tick of the ten-second
+// timer that finds a refresh running is dropped. Each test boots the real popup
+// over a stored profile and holds the ten-second refresh open. `readChain()`
+// sets each address's balance from `CHAIN`, as the real `refreshBalances()`
+// sets it from the node.
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    ADDRESS,
+} = require("./support/popupBoot");
+const {
+    hdWalletFromMnemonic,
+    deriveAddressFromXpub,
+} = require("../src/shared/wallet");
+
+const PHRASE =
+    "abandon abandon abandon abandon abandon abandon " +
+    "abandon abandon abandon abandon abandon about";
+const PASSWORD = "correct horse battery staple";
+
+// The first two addresses of PHRASE, both used on the chain.
+const { xpub, firstAddress } = hdWalletFromMnemonic(PHRASE);
+const SECOND_ADDRESS = deriveAddressFromXpub(xpub, 1);
+
+// The ETH balance the chain holds for each address, in ether.
+const CHAIN = {
+    [ADDRESS]: "1.5",
+    [firstAddress]: "2.0",
+    [SECOND_ADDRESS]: "3.0",
+};
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+// The balance stand-in for a refresh that returns.
+async function readChain(wallets) {
+    for (const wallet of wallets) {
+        for (const addr of wallet.addresses) {
+            addr.balance = CHAIN[addr.address];
+        }
+    }
+}
+
+// Boots the popup over a profile with one wallet. From then on,
+// `refreshBalances()` never returns unless the test answers it. So an unwanted
+// refresh is counted once and then waits, instead of starting more.
+async function boot() {
+    const page = await bootPopup(unversionedValidProfile());
+    expect(page.pageErrors).toEqual([]);
+    const { refreshBalances } = require("../src/shared/balances");
+    refreshBalances.mockImplementation(() => new Promise(() => {}));
+    return { page, refreshBalances };
+}
+
+// Starts the ten-second refresh and holds it open until finish() is called.
+// The held refresh then writes the chain's balances. finish() resolves once
+// the held refresh has saved them and drawn Home. The one refresh after the
+// held one also returns.
+async function holdRefresh(page) {
+    const { refreshBalances } = require("../src/shared/balances");
+    let answer;
+    refreshBalances
+        .mockImplementationOnce(async (wallets) => {
+            await new Promise((resolve) => {
+                answer = resolve;
+            });
+            await readChain(wallets);
+        })
+        .mockImplementationOnce(readChain);
+    const ticking = page.tick();
+    await page.settle();
+    return {
+        finish: async () => {
+            answer();
+            await ticking;
+        },
+    };
+}
+
+// Imports PHRASE on AddWallet. Its address scan finds the phrase's first two
+// addresses.
+async function importPhrase(page) {
+    const { scanForAddresses } = require("../src/shared/balances");
+    scanForAddresses.mockImplementationOnce(async () => ({
+        addresses: [
+            { address: firstAddress, index: 0 },
+            { address: SECOND_ADDRESS, index: 1 },
+        ],
+        nextIndex: 2,
+    }));
+    await page.click("btn-add-wallet-bottom");
+    await page.click("tab-mnemonic");
+    page.node("wallet-mnemonic").value = PHRASE;
+    page.node("add-wallet-password").value = PASSWORD;
+    page.node("add-wallet-password-confirm").value = PASSWORD;
+    await page.click("btn-add-wallet-confirm");
+}
+
+// Imports the private key `key` on AddWallet.
+async function importKey(page, key) {
+    await page.click("btn-add-wallet-bottom");
+    await page.click("tab-privkey");
+    page.node("import-private-key").value = key;
+    page.node("add-wallet-password").value = PASSWORD;
+    page.node("add-wallet-password-confirm").value = PASSWORD;
+    await page.click("btn-add-wallet-confirm");
+}
+
+test("addresses that an import finds during a refresh show their balances once one more refresh returns", async () => {
+    const { page } = await boot();
+    const refresh = await holdRefresh(page);
+
+    await importPhrase(page);
+    expect(page.visibleViews()).toEqual(["main"]);
+    expect(page.text("flash-msg")).toBe("Found 2 addresses.");
+
+    await refresh.finish();
+    await page.settle();
+
+    const list = page.node("wallet-list").innerHTML;
+    expect(list).toContain("<span>2.0000</span>");
+    expect(list).toContain("<span>3.0000</span>");
+});
+
+test("several requests during a refresh lead to exactly one more refresh", async () => {
+    const { page, refreshBalances } = await boot();
+    const refresh = await holdRefresh(page);
+    const calls = refreshBalances.mock.calls.length;
+
+    await importKey(page, "0x" + "11".repeat(32));
+    await importKey(page, "0x" + "22".repeat(32));
+    await importPhrase(page);
+    expect(refreshBalances).toHaveBeenCalledTimes(calls);
+
+    await refresh.finish();
+    await page.settle();
+
+    expect(refreshBalances).toHaveBeenCalledTimes(calls + 1);
+});
+
+test("a tick of the ten-second timer during a refresh starts no other refresh", async () => {
+    const { page, refreshBalances } = await boot();
+    const refresh = await holdRefresh(page);
+    const calls = refreshBalances.mock.calls.length;
+
+    await page.tick();
+
+    await refresh.finish();
+    await page.settle();
+
+    expect(refreshBalances).toHaveBeenCalledTimes(calls);
+});

tests/resolveTokenSymbol.test.js

@@ -67,13 +67,15 @@ beforeEach(() => {
 });
 
 describe("resolveTokenSymbol", () => {
+    // The bundled list is read only for a token on Ethereum Mainnet.
     test("reads the bundled list", () => {
-        expect(resolveTokenSymbol(USDC, state)).toBe("USDC");
+        expect(resolveTokenSymbol(USDC, { chainId: "0x1" })).toBe("USDC");
     });
 
     test("prefers the bundled list over a tracked entry", () => {
         state.trackedTokens = [{ address: USDC, symbol: "NOTUSDC" }];
-        expect(resolveTokenSymbol(USDC, state)).toBe("USDC");
+        const sources = { chainId: "0x1", trackedTokens: state.trackedTokens };
+        expect(resolveTokenSymbol(USDC, sources)).toBe("USDC");
     });
 
     test("reads a token the user tracks", () => {
@@ -104,7 +106,19 @@ describe("resolveTokenSymbol", () => {
     test("rejects a tracked entry claiming a bundled ticker it is not", () => {
         // NOVEL_TOKEN is not the real USDC contract, so it may not wear USDC.
         state.trackedTokens = [{ address: NOVEL_TOKEN, symbol: "USDC" }];
-        expect(resolveTokenSymbol(NOVEL_TOKEN, state)).toBeNull();
+        const sources = { chainId: "0x1", trackedTokens: state.trackedTokens };
+        expect(resolveTokenSymbol(NOVEL_TOKEN, sources)).toBeNull();
+    });
+
+    // The bundled list holds mainnet contracts, so on Sepolia any contract may
+    // carry one of its symbols.
+    test("on Sepolia, reads a tracked entry carrying a bundled ticker", () => {
+        state.trackedTokens = [{ address: NOVEL_TOKEN, symbol: "USDC" }];
+        const sources = {
+            chainId: "0xaa36a7",
+            trackedTokens: state.trackedTokens,
+        };
+        expect(resolveTokenSymbol(NOVEL_TOKEN, sources)).toBe("USDC");
     });
 
     test("rejects an explorer entry claiming the native ETH ticker", () => {

tests/sendAmountRule.test.js

@@ -131,10 +131,14 @@ async function review(amount, token) {
 async function confirm(amount, token) {
     const txInfo = await review("0.5", token);
     confirmTx.show({ ...txInfo, amount });
-    for (let i = 0; i < 10; i++) await new Promise((r) => setTimeout(r, 0));
+    for (let i = 0; i < 10; i++) await jest.advanceTimersByTimeAsync(0);
 }
 
+// showFlash() starts a timer that clears the message two seconds later. Each
+// test here runs on fake timers and drops them in afterEach, so that timer
+// never outlives the test.
 beforeEach(() => {
+    jest.useFakeTimers();
     elements.clear();
     state.wallets = [
         {
@@ -167,6 +171,10 @@ beforeEach(() => {
     state.currentView = null;
 });
 
+afterEach(() => {
+    jest.useRealTimers();
+});
+
 describe.each([
     ["1e-3", "ETH"],
     ["1e-3", "TOK"],

tests/sendMax.test.js

@@ -277,14 +277,18 @@ async function review() {
 
 // show() starts the fee estimate without awaiting it; this lets it settle.
 async function settle() {
-    for (let i = 0; i < 10; i++) await new Promise((r) => setTimeout(r, 0));
+    for (let i = 0; i < 10; i++) await jest.advanceTimersByTimeAsync(0);
 }
 
 function canSend() {
     return !el("btn-confirm-send").disabled;
 }
 
+// showFlash() starts a timer that clears the message two seconds later. Each
+// test here runs on fake timers and drops them in afterEach, so that timer
+// never outlives the test.
 beforeEach(() => {
+    jest.useFakeTimers();
     elements.clear();
     log.errorf.mockClear();
     pageClosed = new AbortController();
@@ -297,6 +301,10 @@ beforeEach(() => {
     mockNode.broadcast = [];
 });
 
+afterEach(() => {
+    jest.useRealTimers();
+});
+
 describe("Max on an ETH send", () => {
     test("fills in the exact balance minus the fee reserve", async () => {
         await refreshWith(BALANCE_WEI);

tests/settingsEndpointSave.test.js

@@ -0,0 +1,438 @@
+// Another page stores a different RPC or Blockscout URL for the same network.
+// Then the user taps "Save" in Settings on this page, on the URL that this page
+// loaded. The URL on screen is stored, and the flash message reads "Saved."
+// (https://git.eeqj.de/sneak/AutistMask/issues/688). Driven through the real
+// popup over a stored profile on Ethereum Mainnet.
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+} = require("./support/popupBoot");
+const { NETWORKS } = require("../src/shared/networks");
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+test.each([
+    { button: "btn-save-rpc", input: "settings-rpc", field: "rpcUrl" },
+    {
+        button: "btn-save-blockscout",
+        input: "settings-blockscout",
+        field: "blockscoutUrl",
+    },
+])(
+    "$button stores the URL on screen after another page stored a different one",
+    async ({ button, input, field }) => {
+        const page = await bootPopup(unversionedValidProfile());
+        await page.click("btn-settings");
+        const url = page.value(input);
+        // This write sends this page no storage change event.
+        page.storage.write("autistmask", {
+            ...page.storage.read("autistmask"),
+            [field]: "https://other-page.example.invalid",
+        });
+        // This answer passes both endpoint checks on Ethereum Mainnet. The RPC
+        // check reads Ethereum Mainnet's chain id from it. The Blockscout check
+        // reads `ok`.
+        globalThis.fetch.mockResolvedValue({
+            ok: true,
+            json: async () => ({ result: NETWORKS.mainnet.chainId }),
+        });
+
+        await page.click(button);
+
+        expect(page.storage.read("autistmask")[field]).toBe(url);
+        expect(page.text("flash-msg")).toBe("Saved.");
+    },
+);
+
+// The user types a URL in Settings and taps "Save". While the check waits for
+// the endpoint's answer, another page turns "Use Blockscout" on. This page
+// follows that change and draws Settings again, with the stored URL in the
+// input. The check then passes. The typed URL is not stored. The flash message
+// says that the URL was changed during the check
+// (https://git.eeqj.de/sneak/AutistMask/issues/695).
+test.each([
+    { button: "btn-save-rpc", input: "settings-rpc", field: "rpcUrl" },
+    {
+        button: "btn-save-blockscout",
+        input: "settings-blockscout",
+        field: "blockscoutUrl",
+    },
+])(
+    "$button stores nothing when Settings is drawn again during the check",
+    async ({ button, input, field }) => {
+        const page = await bootPopup(unversionedValidProfile());
+        await page.click("btn-settings");
+        const storedUrl = page.value(input);
+        let answer;
+        globalThis.fetch.mockReturnValue(
+            new Promise((resolve) => {
+                answer = resolve;
+            }),
+        );
+
+        page.node(input).value = "https://typed.example.invalid";
+        const saving = page.node(button).listeners.click.map((fn) => fn());
+        await page.settle();
+        // The browser announces this write to this page.
+        await page.storage.local.set({
+            autistmask: {
+                ...page.storage.read("autistmask"),
+                useBlockscout: true,
+            },
+        });
+        await page.settle();
+        expect(page.node("settings-use-blockscout").checked).toBe(true);
+        // This answer passes both endpoint checks on Ethereum Mainnet.
+        answer({
+            ok: true,
+            json: async () => ({ result: NETWORKS.mainnet.chainId }),
+        });
+        await Promise.all(saving);
+        await page.settle();
+
+        expect(page.storage.read("autistmask")[field]).toBe(storedUrl);
+        expect(page.value(input)).toBe(storedUrl);
+        expect(page.text("flash-msg")).toBe(
+            "The URL was not saved because it was changed during the check.",
+        );
+    },
+);
+
+// As above, but another write holds the lock. So this page's follow of the
+// change to "Use Blockscout" waits for the lock. The endpoint answers while the
+// input still shows the typed URL. The save then asks for the lock, after the
+// follow did. So the follow draws Settings again before the save compares the
+// input.
+test.each([
+    { button: "btn-save-rpc", input: "settings-rpc", field: "rpcUrl" },
+    {
+        button: "btn-save-blockscout",
+        input: "settings-blockscout",
+        field: "blockscoutUrl",
+    },
+])(
+    "$button stores nothing when Settings is drawn again while the save waits for the lock",
+    async ({ button, input, field }) => {
+        const page = await bootPopup(unversionedValidProfile());
+        await page.click("btn-settings");
+        const storedUrl = page.value(input);
+        let answer;
+        globalThis.fetch.mockReturnValue(
+            new Promise((resolve) => {
+                answer = resolve;
+            }),
+        );
+        const typedUrl = "https://typed.example.invalid";
+
+        page.node(input).value = typedUrl;
+        const saving = page.node(button).listeners.click.map((fn) => fn());
+        await page.settle();
+        let releaseLock;
+        const lockHeld = navigator.locks.request(
+            "autistmask",
+            () =>
+                new Promise((resolve) => {
+                    releaseLock = resolve;
+                }),
+        );
+        // The browser announces this write to this page.
+        await page.storage.local.set({
+            autistmask: {
+                ...page.storage.read("autistmask"),
+                useBlockscout: true,
+            },
+        });
+        await page.settle();
+        // This answer passes both endpoint checks on Ethereum Mainnet.
+        answer({
+            ok: true,
+            json: async () => ({ result: NETWORKS.mainnet.chainId }),
+        });
+        await page.settle();
+        expect(page.value(input)).toBe(typedUrl);
+        releaseLock();
+        await lockHeld;
+        await Promise.all(saving);
+        await page.settle();
+
+        expect(page.node("settings-use-blockscout").checked).toBe(true);
+        expect(page.storage.read("autistmask")[field]).toBe(storedUrl);
+        expect(page.value(input)).toBe(storedUrl);
+        expect(page.text("flash-msg")).toBe(
+            "The URL was not saved because it was changed during the check.",
+        );
+    },
+);
+
+// This answer passes both endpoint checks on Ethereum Mainnet.
+const PASSING_ANSWER = {
+    ok: true,
+    json: async () => ({ result: NETWORKS.mainnet.chainId }),
+};
+
+// Both endpoint checks read this answer as an error. The RPC check reads the
+// answer's `error`. The Blockscout check reads the answer's `ok`.
+const ERROR_ANSWER = {
+    ok: false,
+    status: 500,
+    json: async () => ({ error: { code: -32603, message: "Internal error" } }),
+};
+
+// The user types a URL in Settings and taps "Save". Before the endpoint answers,
+// the user types a second URL and taps "Save" again. The second check passes
+// first. The second URL is stored, and the flash message reads "Saved.". The
+// first check then ends in one of three ways:
+//
+// - It passes.
+// - It fails, because fetch cannot reach the endpoint.
+// - It gets an answer that holds an error.
+//
+// None of the three changes the stored URL or the flash message
+// (https://git.eeqj.de/sneak/AutistMask/issues/698).
+test.each([
+    {
+        button: "btn-save-rpc",
+        input: "settings-rpc",
+        field: "rpcUrl",
+        first: "passes",
+    },
+    {
+        button: "btn-save-rpc",
+        input: "settings-rpc",
+        field: "rpcUrl",
+        first: "fails",
+    },
+    {
+        button: "btn-save-rpc",
+        input: "settings-rpc",
+        field: "rpcUrl",
+        first: "answers with an error",
+    },
+    {
+        button: "btn-save-blockscout",
+        input: "settings-blockscout",
+        field: "blockscoutUrl",
+        first: "passes",
+    },
+    {
+        button: "btn-save-blockscout",
+        input: "settings-blockscout",
+        field: "blockscoutUrl",
+        first: "fails",
+    },
+    {
+        button: "btn-save-blockscout",
+        input: "settings-blockscout",
+        field: "blockscoutUrl",
+        first: "answers with an error",
+    },
+])(
+    "$button keeps the second tap's result when the first check $first last",
+    async ({ button, input, field, first }) => {
+        const page = await bootPopup(unversionedValidProfile());
+        await page.click("btn-settings");
+        const checks = [];
+        globalThis.fetch.mockImplementation(
+            () =>
+                new Promise((resolve, reject) => {
+                    checks.push({ resolve, reject });
+                }),
+        );
+        const secondUrl = "https://second.example.invalid";
+
+        page.node(input).value = "https://first.example.invalid";
+        const firstTap = page.node(button).listeners.click.map((fn) => fn());
+        await page.settle();
+        page.node(input).value = secondUrl;
+        const secondTap = page.node(button).listeners.click.map((fn) => fn());
+        await page.settle();
+        checks[1].resolve(PASSING_ANSWER);
+        await Promise.all(secondTap);
+        await page.settle();
+        expect(page.text("flash-msg")).toBe("Saved.");
+        if (first === "passes") {
+            checks[0].resolve(PASSING_ANSWER);
+        } else if (first === "answers with an error") {
+            checks[0].resolve(ERROR_ANSWER);
+        } else {
+            // fetch rejects when it cannot reach the endpoint.
+            checks[0].reject(new TypeError("Failed to fetch"));
+        }
+        await Promise.all(firstTap);
+        await page.settle();
+
+        expect(checks).toHaveLength(2);
+        expect(page.storage.read("autistmask")[field]).toBe(secondUrl);
+        expect(page.text("flash-msg")).toBe("Saved.");
+    },
+);
+
+// The user types a URL in Settings and taps "Save". Before the endpoint answers,
+// the user empties the input and taps "Save" again. The flash message asks for
+// a URL. The first check then passes. The flash message still asks for a URL,
+// and the stored URL is unchanged.
+test.each([
+    {
+        button: "btn-save-rpc",
+        input: "settings-rpc",
+        field: "rpcUrl",
+        message: "Please enter an RPC URL.",
+    },
+    {
+        button: "btn-save-blockscout",
+        input: "settings-blockscout",
+        field: "blockscoutUrl",
+        message: "Please enter a Blockscout API URL.",
+    },
+])(
+    "$button keeps the empty-input message when the first check passes last",
+    async ({ button, input, field, message }) => {
+        const page = await bootPopup(unversionedValidProfile());
+        await page.click("btn-settings");
+        const storedUrl = page.value(input);
+        let answer;
+        globalThis.fetch.mockReturnValue(
+            new Promise((resolve) => {
+                answer = resolve;
+            }),
+        );
+
+        page.node(input).value = "https://typed.example.invalid";
+        const firstTap = page.node(button).listeners.click.map((fn) => fn());
+        await page.settle();
+        page.node(input).value = "";
+        await page.click(button);
+        expect(page.text("flash-msg")).toBe(message);
+        answer(PASSING_ANSWER);
+        await Promise.all(firstTap);
+        await page.settle();
+
+        expect(page.storage.read("autistmask")[field]).toBe(storedUrl);
+        expect(page.text("flash-msg")).toBe(message);
+    },
+);
+
+// The user types a URL in Settings and taps "Save". Another write holds the
+// lock. So the save waits for the lock once the check passes. The user then
+// taps "Save" again on the same URL. When the lock is free, the first save
+// stores nothing and shows no flash message. The second check then passes, and
+// the second save stores the URL.
+test.each([
+    { button: "btn-save-rpc", input: "settings-rpc", field: "rpcUrl" },
+    {
+        button: "btn-save-blockscout",
+        input: "settings-blockscout",
+        field: "blockscoutUrl",
+    },
+])(
+    "$button stores nothing for an earlier tap still waiting for the lock",
+    async ({ button, input, field }) => {
+        const page = await bootPopup(unversionedValidProfile());
+        await page.click("btn-settings");
+        const storedUrl = page.value(input);
+        const checks = [];
+        globalThis.fetch.mockImplementation(
+            () =>
+                new Promise((resolve) => {
+                    checks.push(resolve);
+                }),
+        );
+        const typedUrl = "https://typed.example.invalid";
+
+        page.node(input).value = typedUrl;
+        const firstTap = page.node(button).listeners.click.map((fn) => fn());
+        await page.settle();
+        let releaseLock;
+        const lockHeld = navigator.locks.request(
+            "autistmask",
+            () =>
+                new Promise((resolve) => {
+                    releaseLock = resolve;
+                }),
+        );
+        checks[0](PASSING_ANSWER);
+        await page.settle();
+        const secondTap = page.node(button).listeners.click.map((fn) => fn());
+        await page.settle();
+        releaseLock();
+        await lockHeld;
+        await Promise.all(firstTap);
+        await page.settle();
+
+        expect(page.storage.read("autistmask")[field]).toBe(storedUrl);
+        expect(page.text("flash-msg")).toBe("Testing endpoint...");
+
+        checks[1](PASSING_ANSWER);
+        await Promise.all(secondTap);
+        await page.settle();
+
+        expect(checks).toHaveLength(2);
+        expect(page.storage.read("autistmask")[field]).toBe(typedUrl);
+        expect(page.text("flash-msg")).toBe("Saved.");
+    },
+);
+
+// The user taps "Save", and the check passes. The save then begins its storage
+// write, and this test keeps the write waiting. The user taps "Save" again, and
+// the second check cannot reach the endpoint. When the write ends, the flash
+// message still reads "Could not reach endpoint.". The write stores the URL
+// anyway, because the write began before the second tap.
+test.each([
+    { button: "btn-save-rpc", input: "settings-rpc", field: "rpcUrl" },
+    {
+        button: "btn-save-blockscout",
+        input: "settings-blockscout",
+        field: "blockscoutUrl",
+    },
+])(
+    "$button keeps the second tap's message when tapped again during the write",
+    async ({ button, input, field }) => {
+        const page = await bootPopup(unversionedValidProfile());
+        await page.click("btn-settings");
+        const checks = [];
+        globalThis.fetch.mockImplementation(
+            () =>
+                new Promise((resolve, reject) => {
+                    checks.push({ resolve, reject });
+                }),
+        );
+        const typedUrl = "https://typed.example.invalid";
+
+        page.node(input).value = typedUrl;
+        const firstTap = page.node(button).listeners.click.map((fn) => fn());
+        await page.settle();
+        const { set } = page.storage.local;
+        const write = set.getMockImplementation();
+        let writeBegan = false;
+        let releaseWrite;
+        const writeHeld = new Promise((resolve) => {
+            releaseWrite = resolve;
+        });
+        set.mockImplementationOnce(async (items) => {
+            writeBegan = true;
+            await writeHeld;
+            await write(items);
+        });
+        checks[0].resolve(PASSING_ANSWER);
+        await page.settle();
+        expect(writeBegan).toBe(true);
+        const secondTap = page.node(button).listeners.click.map((fn) => fn());
+        await page.settle();
+        // fetch rejects when it cannot reach the endpoint.
+        checks[1].reject(new TypeError("Failed to fetch"));
+        await Promise.all(secondTap);
+        await page.settle();
+        expect(page.text("flash-msg")).toBe("Could not reach endpoint.");
+        releaseWrite();
+        await Promise.all(firstTap);
+        await page.settle();
+
+        expect(checks).toHaveLength(2);
+        expect(page.storage.read("autistmask")[field]).toBe(typedUrl);
+        expect(page.text("flash-msg")).toBe("Could not reach endpoint.");
+    },
+);

tests/spoofedTrackedToken.test.js

@@ -0,0 +1,134 @@
+// A token that the spoof rule refuses never shows in the balance list, even
+// tracked at zero balance with "Show tracked tokens with zero balance" on, and
+// the two add-token screens refuse to track one
+// (https://git.eeqj.de/sneak/AutistMask/issues/705). Driven through the real
+// popup over a stored profile.
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    TOKEN_ADDRESS,
+} = require("./support/popupBoot");
+
+// Claims the symbol of the bundled USDT from another contract.
+const FAKE_USDT = {
+    address: TOKEN_ADDRESS,
+    symbol: "USDT",
+    decimals: 6,
+    name: "Tether USD",
+};
+// A Sepolia contract that reports USDT. The bundled list holds Ethereum Mainnet
+// contracts, so the spoof rule does not check this symbol on Sepolia
+// (https://git.eeqj.de/sneak/AutistMask/issues/632).
+const SEPOLIA_USDT = {
+    address: TOKEN_ADDRESS,
+    symbol: "USDT",
+    decimals: 6,
+    name: "Test USDT",
+};
+// A symbol the bundled list does not have, so the spoof rule passes it.
+const TEST_TOKEN = {
+    address: "0xBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB",
+    symbol: "TST",
+    decimals: 18,
+    name: "Test Token",
+};
+const REFUSED_FLASH = "Not added: this token fakes a known symbol.";
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+test("on Ethereum Mainnet, a fake token tracked at zero balance is not listed while zero balances are shown", async () => {
+    const boot = await bootPopup(
+        unversionedValidProfile({
+            networkId: "mainnet",
+            currentView: "address",
+            selectedWallet: 0,
+            selectedAddress: 0,
+            trackedTokens: [FAKE_USDT, TEST_TOKEN],
+            showZeroBalanceTokens: true,
+        }),
+    );
+    const rows = boot.node("address-balances").innerHTML;
+    expect(rows).toContain(`data-token="${TEST_TOKEN.address.toLowerCase()}"`);
+    expect(rows).not.toContain(
+        `data-token="${FAKE_USDT.address.toLowerCase()}"`,
+    );
+});
+
+// Each screen is opened from AddressDetail by the buttons named, in order.
+describe.each([
+    [
+        "AddToken",
+        ["btn-add-token"],
+        "add-token",
+        "add-token-address",
+        "btn-add-token-confirm",
+    ],
+    [
+        "SettingsAddToken",
+        ["btn-settings", "btn-settings-add-token"],
+        "settings-addtoken",
+        "settings-addtoken-address",
+        "btn-settings-addtoken-manual",
+    ],
+])("%s", (_, opening, view, field, button) => {
+    test("on Ethereum Mainnet, refuses a fake token by contract address", async () => {
+        const boot = await bootPopup(
+            unversionedValidProfile({
+                networkId: "mainnet",
+                currentView: "address",
+                selectedWallet: 0,
+                selectedAddress: 0,
+            }),
+        );
+        for (const id of opening) await boot.click(id);
+        expect(boot.visibleViews()).toEqual([view]);
+        const { lookupTokenInfo } = require("../src/shared/balances");
+        lookupTokenInfo.mockResolvedValueOnce({
+            symbol: FAKE_USDT.symbol,
+            decimals: FAKE_USDT.decimals,
+            name: FAKE_USDT.name,
+        });
+        boot.node(field).value = FAKE_USDT.address;
+
+        await boot.click(button);
+        expect(boot.text("flash-msg")).toBe(REFUSED_FLASH);
+        expect(boot.visibleViews()).toEqual([view]);
+        expect(boot.storage.read("autistmask").trackedTokens).toEqual([]);
+    });
+
+    test("on Sepolia, adds a contract that reports USDT and lists it", async () => {
+        const boot = await bootPopup(
+            unversionedValidProfile({
+                networkId: "sepolia",
+                currentView: "address",
+                selectedWallet: 0,
+                selectedAddress: 0,
+                showZeroBalanceTokens: true,
+            }),
+        );
+        for (const id of opening) await boot.click(id);
+        expect(boot.visibleViews()).toEqual([view]);
+        const { lookupTokenInfo } = require("../src/shared/balances");
+        lookupTokenInfo.mockResolvedValueOnce({
+            symbol: SEPOLIA_USDT.symbol,
+            decimals: SEPOLIA_USDT.decimals,
+            name: SEPOLIA_USDT.name,
+        });
+        boot.node(field).value = SEPOLIA_USDT.address;
+
+        await boot.click(button);
+        expect(boot.text("flash-msg")).not.toBe(REFUSED_FLASH);
+        expect(boot.storage.read("autistmask").trackedTokens).toEqual([
+            expect.objectContaining(SEPOLIA_USDT),
+        ]);
+        // SettingsAddToken stays up after adding, so this draws AddressDetail.
+        require("../src/popup/views/addressDetail").show();
+        expect(boot.node("address-balances").innerHTML).toContain(
+            `data-token="${SEPOLIA_USDT.address.toLowerCase()}"`,
+        );
+    });
+});

tests/support/popupBoot.js

@@ -279,10 +279,11 @@ async function bootPopup(stored, options) {
         getAddressValue: () => ({ usd: null, partial: false }),
     }));
     // scanForAddresses() answers in the real one's shape, a scan that found
-    // no used address: AddWallet reads `addresses` from it.
+    // no used address: AddWallet reads `addresses` from it. refreshBalances()
+    // answers as a refresh that read no tracked token's balance.
     jest.doMock("../../src/shared/balances", () => ({
         fetchTokenBalances: jest.fn(async () => []),
-        refreshBalances: jest.fn(async () => {}),
+        refreshBalances: jest.fn(async () => []),
         dropUntrackedTokens: jest.requireActual("../../src/shared/balances")
             .dropUntrackedTokens,
         lookupTokenInfo: jest.fn(async () => null),

tests/symbolSpoof.test.js

@@ -72,6 +72,11 @@ const {
 const { renderSendTokenSelect } = require("../src/popup/views/send");
 const { state } = require("../src/shared/state");
 const { debugFetch } = require("../src/shared/log");
+const { NETWORKS } = require("../src/shared/networks");
+
+// The bundled list's symbols are known symbols only on Ethereum Mainnet.
+const MAINNET = NETWORKS.mainnet.chainId;
+const SEPOLIA = NETWORKS.sepolia.chainId;
 
 // The fake "Ethereum" token with symbol "ETH" from the attack documented in
 // README.md, given a holder count high enough to clear every other filter so
@@ -116,14 +121,29 @@ describe("the shared rule", () => {
     });
 
     test("a known symbol from its own contract is not a spoof", () => {
-        expect(isSpoofedSymbol("USDC", USDC_CONTRACT)).toBe(false);
-        expect(isSpoofedSymbol("usdc", USDC_CONTRACT.toUpperCase())).toBe(
-            false,
-        );
+        expect(isSpoofedSymbol("USDC", USDC_CONTRACT, MAINNET)).toBe(false);
+        expect(
+            isSpoofedSymbol("usdc", USDC_CONTRACT.toUpperCase(), MAINNET),
+        ).toBe(false);
     });
 
     test("a known symbol from another contract is a spoof", () => {
-        expect(isSpoofedSymbol("USDC", FAKE_ETH_CONTRACT)).toBe(true);
+        expect(isSpoofedSymbol("USDC", FAKE_ETH_CONTRACT, MAINNET)).toBe(true);
+    });
+
+    // https://git.eeqj.de/sneak/AutistMask/issues/632: the bundled list holds
+    // mainnet contracts, so on Sepolia any contract may carry one of its
+    // symbols.
+    test("on Sepolia, a bundled symbol from any contract is not a spoof", () => {
+        expect(isSpoofedSymbol("USDC", FAKE_ETH_CONTRACT, SEPOLIA)).toBe(false);
+        expect(isSpoofedSymbol("USDC", USDC_CONTRACT, SEPOLIA)).toBe(false);
+    });
+
+    test("on Sepolia, the native asset's labels are still reserved", () => {
+        expect(isSpoofedSymbol("ETH", FAKE_ETH_CONTRACT, SEPOLIA)).toBe(true);
+        expect(isSpoofedSymbol("SepoliaETH", FAKE_ETH_CONTRACT, SEPOLIA)).toBe(
+            true,
+        );
     });
 
     test("a symbol that is not in the table is not judged here", () => {
@@ -164,7 +184,9 @@ describe("the shared rule: symbols that render as a known symbol", () => {
     test("ASCII padding does not buy a pass", () => {
         expect(isSpoofedSymbol(" ETH ", FAKE_ETH_CONTRACT)).toBe(true);
         expect(isSpoofedSymbol("\tETH\n", FAKE_ETH_CONTRACT)).toBe(true);
-        expect(isSpoofedSymbol("  usdc  ", FAKE_ETH_CONTRACT)).toBe(true);
+        expect(isSpoofedSymbol("  usdc  ", FAKE_ETH_CONTRACT, MAINNET)).toBe(
+            true,
+        );
     });
 
     test("non-breaking and other Unicode spaces do not either", () => {
@@ -243,7 +265,9 @@ describe("the shared rule: symbols that render as a known symbol", () => {
 
     test("compatibility forms fold onto the symbol they imitate", () => {
         expect(isSpoofedSymbol(FULLWIDTH_ETH, FAKE_ETH_CONTRACT)).toBe(true);
-        expect(isSpoofedSymbol(FULLWIDTH_USDC, FAKE_ETH_CONTRACT)).toBe(true);
+        expect(
+            isSpoofedSymbol(FULLWIDTH_USDC, FAKE_ETH_CONTRACT, MAINNET),
+        ).toBe(true);
     });
 
     // The two knowingly open classes, asserted here so that the boundary is
@@ -271,8 +295,10 @@ describe("the shared rule: symbols that render as a known symbol", () => {
     });
 
     test("a genuine contract still bears its own padded symbol", () => {
-        expect(isSpoofedSymbol(" USDC ", USDC_CONTRACT)).toBe(false);
-        expect(isSpoofedSymbol(ZWSP + "WETH", WETH_CONTRACT)).toBe(false);
+        expect(isSpoofedSymbol(" USDC ", USDC_CONTRACT, MAINNET)).toBe(false);
+        expect(isSpoofedSymbol(ZWSP + "WETH", WETH_CONTRACT, MAINNET)).toBe(
+            false,
+        );
     });
 
     // Normalization must not invent a match.  Interior ASCII whitespace is
@@ -296,7 +322,7 @@ describe("the shared rule: symbols that render as a known symbol", () => {
             expect(symbol).toMatch(/^[!-~]+$/);
             if (addresses === null) continue;
             for (const address of addresses) {
-                expect(isSpoofedSymbol(symbol, address)).toBe(false);
+                expect(isSpoofedSymbol(symbol, address, MAINNET)).toBe(false);
             }
         }
     });
@@ -317,7 +343,7 @@ describe("the shared rule: symbols that render as a known symbol", () => {
 describe("the shipped token list", () => {
     test("no bundled token is filtered at its own address", () => {
         const filtered = TOKENS.filter((t) =>
-            isSpoofedSymbol(t.symbol, t.address),
+            isSpoofedSymbol(t.symbol, t.address, MAINNET),
         ).map((t) => t.symbol + " @ " + t.address);
         expect(filtered).toEqual([]);
     });
@@ -360,7 +386,9 @@ describe("the shipped token list", () => {
         expect(shared.length).toBeGreaterThan(0);
         for (const [, list] of shared) {
             for (const t of list) {
-                expect(isSpoofedSymbol(t.symbol, t.address)).toBe(false);
+                expect(isSpoofedSymbol(t.symbol, t.address, MAINNET)).toBe(
+                    false,
+                );
             }
         }
     });
@@ -404,7 +432,7 @@ describe("the shipped token list", () => {
                 [...addresses].sort(),
             );
             for (const address of addresses) {
-                expect(isSpoofedSymbol(symbol, address)).toBe(false);
+                expect(isSpoofedSymbol(symbol, address, MAINNET)).toBe(false);
             }
         }
     });
@@ -421,7 +449,9 @@ describe("the shipped token list", () => {
         }
         for (const [symbol, list] of bySymbol) {
             if (list.length < 2) continue;
-            expect(isSpoofedSymbol(symbol, FAKE_ETH_CONTRACT)).toBe(true);
+            expect(isSpoofedSymbol(symbol, FAKE_ETH_CONTRACT, MAINNET)).toBe(
+                true,
+            );
         }
     });
 });
@@ -506,10 +536,40 @@ describe("surface 2: the Send token selector", () => {
     }
 
     beforeEach(() => {
+        state.networkId = "mainnet";
         state.fraudContracts = [];
         state.hideLowHolderTokens = true;
     });
 
+    afterAll(() => {
+        state.networkId = "mainnet";
+    });
+
+    // A token reporting USDC's symbol from another contract.
+    function otherUsdc() {
+        return {
+            address: FAKE_ETH_CONTRACT,
+            symbol: "USDC",
+            decimals: 6,
+            balance: "12.5",
+            holders: 900000,
+        };
+    }
+
+    test("a bundled symbol from another contract is not selectable", () => {
+        render([otherUsdc()]);
+        expect(select.children).toEqual([]);
+    });
+
+    // https://git.eeqj.de/sneak/AutistMask/issues/632: the bundled list holds
+    // mainnet contracts, so on Sepolia any contract may carry its symbols.
+    test("with Sepolia active, a bundled symbol from another contract is selectable", () => {
+        state.networkId = "sepolia";
+        render([otherUsdc()]);
+        expect(select.children).toHaveLength(1);
+        expect(select.children[0].value).toBe(FAKE_ETH_CONTRACT);
+    });
+
     test("a fake ETH token is not selectable", () => {
         render([
             {
@@ -627,7 +687,12 @@ describe("surface 3: the balance list", () => {
                 decimals: "6",
             }),
         ]);
-        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
+        const balances = await fetchTokenBalances(
+            HOLDER,
+            BLOCKSCOUT,
+            [],
+            MAINNET,
+        );
         expect(balances).toHaveLength(1);
         expect(balances[0].symbol).toBe(" USDC ");
     });
@@ -641,11 +706,40 @@ describe("surface 3: the balance list", () => {
                 decimals: "6",
             }),
         ]);
-        const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
+        const balances = await fetchTokenBalances(
+            HOLDER,
+            BLOCKSCOUT,
+            [],
+            MAINNET,
+        );
         expect(balances).toHaveLength(1);
         expect(balances[0].symbol).toBe("USDC");
     });
 
+    // https://git.eeqj.de/sneak/AutistMask/issues/632: the bundled list holds
+    // mainnet contracts, so on Sepolia any contract may carry its symbols.
+    test("a bundled symbol from another contract is listed on Sepolia only", async () => {
+        respondWith([fakeEthItem({ symbol: "USDC", decimals: "6" })]);
+        expect(
+            await fetchTokenBalances(HOLDER, BLOCKSCOUT, [], MAINNET),
+        ).toEqual([]);
+        const sepolia = await fetchTokenBalances(
+            HOLDER,
+            BLOCKSCOUT,
+            [],
+            SEPOLIA,
+        );
+        expect(sepolia).toHaveLength(1);
+        expect(sepolia[0].symbol).toBe("USDC");
+    });
+
+    test("a fake ETH token is filtered on Sepolia too", async () => {
+        respondWith([fakeEthItem()]);
+        expect(
+            await fetchTokenBalances(HOLDER, BLOCKSCOUT, [], SEPOLIA),
+        ).toEqual([]);
+    });
+
     // The trap in this change: the user's real ETH balance is not an ERC-20
     // and is fetched over RPC in refreshBalances, so it never passes through
     // this loop at all.  An explorer row that is not an ERC-20 is dropped

tests/trackedTokenBalances.test.js

@@ -133,13 +133,13 @@ function trackedRow(balance, decimals = null, holders = null) {
     };
 }
 
-async function refresh(addresses, trackedTokens) {
+async function refresh(addresses, trackedTokens, networkId = "mainnet") {
     await refreshBalances(
         [{ addresses }],
         RPC_URL,
         EXPLORER_URL,
         trackedTokens,
-        "mainnet",
+        networkId,
         new AbortController().signal,
     );
     return addresses;
@@ -307,3 +307,104 @@ test("a tracked token wearing a known symbol from another contract is not listed
     );
     expect(first.tokenBalances).toEqual([]);
 });
+
+test("the refresh resolves with each tracked token whose balance it read at every address", async () => {
+    const flaky = "0x9999999999999999999999999999999999999999";
+    holdings[TOKEN] = { [FIRST]: 2000000n, [SECOND]: 0n };
+    // balanceOf answers at FIRST and fails at SECOND.
+    holdings[flaky] = { [FIRST]: 2000000n };
+    const read = await refreshBalances(
+        [
+            {
+                addresses: [
+                    { address: FIRST, tokenBalances: [] },
+                    { address: SECOND, tokenBalances: [] },
+                ],
+            },
+        ],
+        RPC_URL,
+        EXPLORER_URL,
+        [
+            TRACKED,
+            { address: flaky, symbol: "FLK", name: "Flaky", decimals: 6 },
+            // A known symbol from another contract: its balance is not read.
+            { address: OTHER, symbol: "USDC", name: "Fake", decimals: 6 },
+        ],
+        "mainnet",
+        new AbortController().signal,
+    );
+    expect(read).toEqual([TOKEN]);
+});
+
+// https://git.eeqj.de/sneak/AutistMask/issues/632: the bundled list holds
+// Ethereum Mainnet contracts. A token outside the tracked tokens with an
+// unknown holder count is listed only when the bundled list names it.
+test("an untracked bundled token with an unknown holder count is listed on Ethereum Mainnet only", async () => {
+    explorerRows = [explorerRow(USDC, "USDC", 5000000, null)];
+    const [mainnet] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        [],
+    );
+    expect(mainnet.tokenBalances).toEqual([
+        {
+            address: USDC,
+            name: "USDC",
+            symbol: "USDC",
+            decimals: 6,
+            balance: "5.0",
+            holders: null,
+        },
+    ]);
+    const [sepolia] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        [],
+        "sepolia",
+    );
+    expect(sepolia.tokenBalances).toEqual([]);
+});
+
+test("a tracked token at a bundled token's address takes the bundled scale on Ethereum Mainnet only", async () => {
+    holdings[USDC] = { [FIRST]: 5000000n };
+    // The tracked entry records no decimals, and Blockscout fails.
+    const tracked = [
+        { address: USDC, symbol: "USDC", name: "USD Coin", decimals: null },
+    ];
+    const row = (balance) => ({
+        address: USDC,
+        name: "USD Coin",
+        symbol: "USDC",
+        decimals: null,
+        balance: balance,
+        holders: null,
+    });
+    const [mainnet] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        tracked,
+    );
+    expect(mainnet.tokenBalances).toEqual([row("5.0")]);
+    const [sepolia] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        tracked,
+        "sepolia",
+    );
+    expect(sepolia.tokenBalances).toEqual([row(null)]);
+});
+
+test("with Sepolia active, a tracked token wearing a bundled symbol from another contract is listed", async () => {
+    holdings[OTHER] = { [FIRST]: 5000000n };
+    const [first] = await refresh(
+        [{ address: FIRST, tokenBalances: [] }],
+        [{ address: OTHER, symbol: "USDC", name: "Other", decimals: 6 }],
+        "sepolia",
+    );
+    expect(first.tokenBalances).toEqual([
+        {
+            address: OTHER,
+            name: "Other",
+            symbol: "USDC",
+            decimals: null,
+            balance: "5.0",
+            holders: null,
+        },
+    ]);
+});

tests/trackedTokensPerNetwork.test.js

@@ -5,6 +5,9 @@
 // a contract lookup that answers after one. Driven through the real popup over
 // a stored profile; the same switch made by the background is in
 // tests/coldWorkerChainSwitch.test.js.
+//
+// The tests of what another page stored before a switch in Settings cover a
+// fraud contract too (https://git.eeqj.de/sneak/AutistMask/issues/692).
 
 const {
     bootPopup,
@@ -159,7 +162,9 @@ test("a token added by contract address on Sepolia is tracked on Sepolia only",
         "sepolia",
         expect.anything(),
     );
-    expect(stored().trackedTokens).toEqual([SEPOLIA_TOKEN]);
+    // No refresh has read the new token's balance yet.
+    const added = { ...SEPOLIA_TOKEN, balanceNotFetched: true };
+    expect(stored().trackedTokens).toEqual([added]);
 
     await boot.click("btn-settings");
     await chooseNetwork(boot, "mainnet");
@@ -171,12 +176,515 @@ test("a token added by contract address on Sepolia is tracked on Sepolia only",
 
     await chooseNetwork(boot, "sepolia");
     expect(stored().networkId).toBe("sepolia");
-    expect(stored().trackedTokens).toEqual([SEPOLIA_TOKEN]);
+    expect(stored().trackedTokens).toEqual([added]);
     const onSepolia = boot.node("settings-tracked-tokens").innerHTML;
     expect(onSepolia).toContain("TST");
     expect(onSepolia).not.toContain("DAI");
 });
 
+// Another popup page tracks DAI on Ethereum Mainnet after this page's last
+// save. The switch to Sepolia puts DAI away under Ethereum Mainnet.
+test("a token another page tracked before a switch in Settings stays tracked on Ethereum Mainnet", async () => {
+    const boot = await bootPopup(unversionedValidProfile());
+    expect(boot.pageErrors).toEqual([]);
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        trackedTokens: [MAINNET_TOKEN],
+    });
+
+    await boot.click("btn-settings");
+    await chooseNetwork(boot, "sepolia");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([MAINNET_TOKEN]);
+});
+
+// Another popup page stops tracking DAI on Ethereum Mainnet after this page's
+// last save. This page still holds DAI. The switch to Sepolia does not store
+// DAI under Ethereum Mainnet again.
+test("a token another page removed before a switch in Settings stays removed", async () => {
+    const boot = await bootPopup(
+        unversionedValidProfile({ trackedTokens: [MAINNET_TOKEN] }),
+    );
+    expect(boot.pageErrors).toEqual([]);
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        trackedTokens: [],
+    });
+
+    await boot.click("btn-settings");
+    await chooseNetwork(boot, "sepolia");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([]);
+});
+
+// Another popup page removes DAI after this page's last save. That page then
+// adds DAI again, typing the contract address in lower case. The two pages'
+// entries for DAI match, because contract addresses are compared ignoring
+// letter case. The switch to Sepolia keeps this page's entry under Ethereum
+// Mainnet.
+test("a token another page added again with a lower-case address keeps this page's entry", async () => {
+    const boot = await bootPopup(
+        unversionedValidProfile({ trackedTokens: [MAINNET_TOKEN] }),
+    );
+    expect(boot.pageErrors).toEqual([]);
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        trackedTokens: [
+            { ...MAINNET_TOKEN, address: MAINNET_TOKEN.address.toLowerCase() },
+        ],
+    });
+
+    await boot.click("btn-settings");
+    await chooseNetwork(boot, "sepolia");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.networkTrackedTokens.mainnet).toEqual([MAINNET_TOKEN]);
+});
+
+// Another popup page saves a switch to Sepolia after this page's last save.
+// TST is tracked on Sepolia. This page has not taken that switch yet. A switch
+// to Sepolia in this page's Settings keeps TST off Ethereum Mainnet's list.
+test("a token tracked on Sepolia when another page switched there is not tracked on Ethereum Mainnet", async () => {
+    const boot = await bootPopup(unversionedValidProfile());
+    expect(boot.pageErrors).toEqual([]);
+    await boot.click("btn-settings");
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        networkId: "sepolia",
+        trackedTokens: [SEPOLIA_TOKEN],
+    });
+
+    await chooseNetwork(boot, "sepolia");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([SEPOLIA_TOKEN]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([]);
+});
+
+// Another popup page saves a switch to Sepolia, where TST is tracked. Before
+// taking that switch, this page adds a token on Ethereum Mainnet. The add's
+// save adds the token to Ethereum Mainnet's list and leaves Sepolia's list as
+// it was.
+test("a token added before this page takes another page's switch is tracked on Ethereum Mainnet", async () => {
+    const boot = await bootOnAddToken("mainnet", {
+        trackedTokens: [MAINNET_TOKEN],
+        networkTrackedTokens: { sepolia: [SEPOLIA_TOKEN] },
+    });
+    expect(boot.pageErrors).toEqual([]);
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        networkId: "sepolia",
+        trackedTokens: [SEPOLIA_TOKEN],
+        networkTrackedTokens: {
+            mainnet: [MAINNET_TOKEN],
+            sepolia: [SEPOLIA_TOKEN],
+        },
+    });
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    lookupTokenInfo.mockResolvedValueOnce({
+        symbol: "NEW",
+        decimals: 18,
+        name: "New Token",
+    });
+
+    boot.node("settings-addtoken-address").value = NEW_TOKEN_ADDRESS;
+    await boot.click("btn-settings-addtoken-manual");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([SEPOLIA_TOKEN]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([
+        MAINNET_TOKEN,
+        {
+            address: NEW_TOKEN_ADDRESS,
+            symbol: "NEW",
+            decimals: 18,
+            name: "New Token",
+            balanceNotFetched: true,
+        },
+    ]);
+});
+
+// Another popup page tracks DAI on Ethereum Mainnet and then saves a switch to
+// Sepolia. This page does not track DAI. Before taking that switch, this page
+// adds a token on Ethereum Mainnet. The add's save puts both DAI and the new
+// token on Ethereum Mainnet's list.
+test("a token added before this page takes another page's switch joins that page's tokens on Ethereum Mainnet", async () => {
+    const boot = await bootOnAddToken("mainnet");
+    expect(boot.pageErrors).toEqual([]);
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        networkId: "sepolia",
+        trackedTokens: [],
+        networkTrackedTokens: { mainnet: [MAINNET_TOKEN] },
+    });
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    lookupTokenInfo.mockResolvedValueOnce({
+        symbol: "NEW",
+        decimals: 18,
+        name: "New Token",
+    });
+
+    boot.node("settings-addtoken-address").value = NEW_TOKEN_ADDRESS;
+    await boot.click("btn-settings-addtoken-manual");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([
+        MAINNET_TOKEN,
+        {
+            address: NEW_TOKEN_ADDRESS,
+            symbol: "NEW",
+            decimals: 18,
+            name: "New Token",
+            balanceNotFetched: true,
+        },
+    ]);
+});
+
+// Another popup page saves a switch to Sepolia, where TST is tracked. Before
+// taking that switch, this page removes DAI on Ethereum Mainnet, as the `[x]`
+// on a tracked token in Settings does. The removal's save drops DAI from
+// Ethereum Mainnet's list and leaves Sepolia's list as it was.
+test("a token removed before this page takes another page's switch is gone from Ethereum Mainnet", async () => {
+    const boot = await bootPopup(
+        unversionedValidProfile({
+            trackedTokens: [MAINNET_TOKEN],
+            networkTrackedTokens: { sepolia: [SEPOLIA_TOKEN] },
+        }),
+    );
+    expect(boot.pageErrors).toEqual([]);
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        networkId: "sepolia",
+        trackedTokens: [SEPOLIA_TOKEN],
+        networkTrackedTokens: {
+            mainnet: [MAINNET_TOKEN],
+            sepolia: [SEPOLIA_TOKEN],
+        },
+    });
+
+    const { state, saveState } = require("../src/shared/state");
+    state.trackedTokens.splice(0, 1);
+    await saveState();
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([SEPOLIA_TOKEN]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([]);
+});
+
+// Another popup page tracks DAI on Ethereum Mainnet and then saves a switch to
+// Sepolia. That switch puts DAI away under Ethereum Mainnet. This page has not
+// taken the switch yet. A switch to Sepolia in this page's Settings keeps DAI
+// on Ethereum Mainnet's list.
+test("a token another page tracked before its own switch stays tracked on Ethereum Mainnet", async () => {
+    const boot = await bootPopup(unversionedValidProfile());
+    expect(boot.pageErrors).toEqual([]);
+    await boot.click("btn-settings");
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        networkId: "sepolia",
+        trackedTokens: [],
+        networkTrackedTokens: { mainnet: [MAINNET_TOKEN] },
+    });
+
+    await chooseNetwork(boot, "sepolia");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.networkTrackedTokens.mainnet).toEqual([MAINNET_TOKEN]);
+});
+
+// This page switches to Sepolia. Another popup page has not taken that switch,
+// and its save adds a token to Ethereum Mainnet's list. This page switches back
+// and tracks that token.
+test("a token another page added on Ethereum Mainnet is tracked when this page switches back there", async () => {
+    const boot = await bootPopup(
+        unversionedValidProfile({ trackedTokens: [MAINNET_TOKEN] }),
+    );
+    expect(boot.pageErrors).toEqual([]);
+    await boot.click("btn-settings");
+    await chooseNetwork(boot, "sepolia");
+    const newToken = {
+        address: NEW_TOKEN_ADDRESS,
+        symbol: "NEW",
+        decimals: 18,
+        name: "New Token",
+    };
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        networkTrackedTokens: { mainnet: [MAINNET_TOKEN, newToken] },
+    });
+
+    await chooseNetwork(boot, "mainnet");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("mainnet");
+    expect(stored.trackedTokens).toEqual([MAINNET_TOKEN, newToken]);
+});
+
+// This page tracks DAI on Ethereum Mainnet and switches to Sepolia. Another
+// popup page has not taken that switch, and its save removes DAI from Ethereum
+// Mainnet's list. This page switches back and does not track DAI again.
+test("a token another page removed on Ethereum Mainnet stays removed when this page switches back there", async () => {
+    const boot = await bootPopup(
+        unversionedValidProfile({ trackedTokens: [MAINNET_TOKEN] }),
+    );
+    expect(boot.pageErrors).toEqual([]);
+    await boot.click("btn-settings");
+    await chooseNetwork(boot, "sepolia");
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        networkTrackedTokens: { mainnet: [] },
+    });
+
+    await chooseNetwork(boot, "mainnet");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("mainnet");
+    expect(stored.trackedTokens).toEqual([]);
+});
+
+// Another popup page records a fraud contract on Ethereum Mainnet after this
+// page's last save. The switch to Sepolia drops that fraud contract, as the
+// switch drops this page's own.
+test("a fraud contract another page recorded before a switch in Settings is not kept on Sepolia", async () => {
+    const boot = await bootPopup(unversionedValidProfile());
+    expect(boot.pageErrors).toEqual([]);
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        fraudContracts: [NEW_TOKEN_ADDRESS],
+    });
+
+    await boot.click("btn-settings");
+    await chooseNetwork(boot, "sepolia");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.fraudContracts).toEqual([]);
+});
+
+// The contract lookup on SettingsAddToken answers on Ethereum Mainnet while the
+// switch to Sepolia waits for the lock. The page adds the token to Ethereum
+// Mainnet's list. The switch then keeps that list for Ethereum Mainnet.
+test("a token added while a switch in Settings waits for the lock stays tracked on Ethereum Mainnet", async () => {
+    const boot = await bootOnAddToken("mainnet");
+    expect(boot.pageErrors).toEqual([]);
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    let answer;
+    lookupTokenInfo.mockImplementationOnce(
+        () =>
+            new Promise((resolve) => {
+                answer = resolve;
+            }),
+    );
+    boot.node("settings-addtoken-address").value = NEW_TOKEN_ADDRESS;
+    const adding = boot.click("btn-settings-addtoken-manual");
+    await boot.click("btn-settings");
+
+    // Another write holds the lock, so the switch's save waits for it.
+    let releaseLock;
+    const lockHeld = navigator.locks.request(
+        "autistmask",
+        () =>
+            new Promise((resolve) => {
+                releaseLock = resolve;
+            }),
+    );
+    const select = boot.node("settings-network");
+    select.value = "sepolia";
+    const switching = Promise.all(select.listeners.change.map((fn) => fn()));
+    await boot.settle();
+
+    answer({ symbol: "NEW", decimals: 18, name: "New Token" });
+    await boot.settle();
+    releaseLock();
+    await lockHeld;
+    await switching;
+    await adding;
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([
+        {
+            address: NEW_TOKEN_ADDRESS,
+            symbol: "NEW",
+            decimals: 18,
+            name: "New Token",
+            balanceNotFetched: true,
+        },
+    ]);
+});
+
+// The contract lookup on SettingsAddToken answers on Ethereum Mainnet while
+// this page's switch to Sepolia waits for the lock. Another popup page holds
+// the lock and stores its own switch to Sepolia, with DAI tracked on Ethereum
+// Mainnet. This page's switch keeps DAI and the new token on Ethereum Mainnet's
+// list.
+test("a token added while a switch in Settings waits for another page's switch stays tracked on Ethereum Mainnet", async () => {
+    const boot = await bootOnAddToken("mainnet");
+    expect(boot.pageErrors).toEqual([]);
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    let answer;
+    lookupTokenInfo.mockImplementationOnce(
+        () =>
+            new Promise((resolve) => {
+                answer = resolve;
+            }),
+    );
+    boot.node("settings-addtoken-address").value = NEW_TOKEN_ADDRESS;
+    const adding = boot.click("btn-settings-addtoken-manual");
+    await boot.click("btn-settings");
+
+    let releaseLock;
+    const lockHeld = navigator.locks.request(
+        "autistmask",
+        () =>
+            new Promise((resolve) => {
+                releaseLock = resolve;
+            }),
+    );
+    const select = boot.node("settings-network");
+    select.value = "sepolia";
+    const switching = Promise.all(select.listeners.change.map((fn) => fn()));
+    await boot.settle();
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        networkId: "sepolia",
+        trackedTokens: [],
+        networkTrackedTokens: { mainnet: [MAINNET_TOKEN] },
+    });
+
+    answer({ symbol: "NEW", decimals: 18, name: "New Token" });
+    await boot.settle();
+    releaseLock();
+    await lockHeld;
+    await switching;
+    await adding;
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([
+        MAINNET_TOKEN,
+        {
+            address: NEW_TOKEN_ADDRESS,
+            symbol: "NEW",
+            decimals: 18,
+            name: "New Token",
+            balanceNotFetched: true,
+        },
+    ]);
+});
+
+// Another popup page holds the lock and stores its switch to Sepolia, with DAI
+// tracked on Ethereum Mainnet. This page waits for the lock to take that
+// switch. Meanwhile, the contract lookup on SettingsAddToken answers on
+// Ethereum Mainnet. When this page takes that switch, DAI and the new token
+// stay on Ethereum Mainnet's list.
+test("a token added while this page waits to take another page's switch stays tracked on Ethereum Mainnet", async () => {
+    const boot = await bootOnAddToken("mainnet");
+    expect(boot.pageErrors).toEqual([]);
+    let releaseLock;
+    const lockHeld = navigator.locks.request(
+        "autistmask",
+        () =>
+            new Promise((resolve) => {
+                releaseLock = resolve;
+            }),
+    );
+    await boot.storage.local.set({
+        autistmask: {
+            ...boot.storage.read("autistmask"),
+            networkId: "sepolia",
+            trackedTokens: [],
+            networkTrackedTokens: { mainnet: [MAINNET_TOKEN] },
+        },
+    });
+    await boot.settle();
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    lookupTokenInfo.mockResolvedValueOnce({
+        symbol: "NEW",
+        decimals: 18,
+        name: "New Token",
+    });
+
+    boot.node("settings-addtoken-address").value = NEW_TOKEN_ADDRESS;
+    const adding = boot.click("btn-settings-addtoken-manual");
+    await boot.settle();
+    releaseLock();
+    await lockHeld;
+    await adding;
+    await boot.settle();
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([
+        MAINNET_TOKEN,
+        {
+            address: NEW_TOKEN_ADDRESS,
+            symbol: "NEW",
+            decimals: 18,
+            name: "New Token",
+            balanceNotFetched: true,
+        },
+    ]);
+});
+
+// This page tracks DAI on Ethereum Mainnet. Another popup page holds the lock
+// and stores its switch to Sepolia, with DAI on Ethereum Mainnet's list. This
+// page waits for the lock to take that switch. Meanwhile, the user removes DAI,
+// as the `[x]` on a tracked token in Settings does. When this page takes that
+// switch, DAI is gone from Ethereum Mainnet's list.
+test("a token removed while this page waits to take another page's switch is gone from Ethereum Mainnet", async () => {
+    const boot = await bootPopup(
+        unversionedValidProfile({ trackedTokens: [MAINNET_TOKEN] }),
+    );
+    expect(boot.pageErrors).toEqual([]);
+    let releaseLock;
+    const lockHeld = navigator.locks.request(
+        "autistmask",
+        () =>
+            new Promise((resolve) => {
+                releaseLock = resolve;
+            }),
+    );
+    await boot.storage.local.set({
+        autistmask: {
+            ...boot.storage.read("autistmask"),
+            networkId: "sepolia",
+            trackedTokens: [],
+            networkTrackedTokens: { mainnet: [MAINNET_TOKEN] },
+        },
+    });
+    await boot.settle();
+
+    const { state, saveState } = require("../src/shared/state");
+    state.trackedTokens.splice(0, 1);
+    const removing = saveState();
+    releaseLock();
+    await lockHeld;
+    await removing;
+    await boot.settle();
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([]);
+});
+
 describe("Back after a switch from the Settings gear", () => {
     test("SettingsAddToken no longer offers the common tokens", async () => {
         const boot = await bootOnAddToken("mainnet");

tests/transactionDetailLateAnswer.test.js

@@ -0,0 +1,202 @@
+// TransactionDetail shows only details that Blockscout gave for the
+// transaction on screen (https://git.eeqj.de/sneak/AutistMask/issues/675).
+//
+// The screen asks Blockscout for its transaction and does not wait for the
+// answer. So the user can press Back and open another transaction before
+// Blockscout answers for the first. The first answer must then fill nothing on
+// the second transaction's screen. An answer that lands while Settings is up
+// must still fill TransactionDetail.
+//
+// Driven through the real popup over a stored profile
+// (tests/support/popupBoot.js). Each transaction is opened as a history screen
+// opens it: the current screen is pushed, then transactionDetail.show() draws
+// the transaction.
+
+"use strict";
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    ADDRESS,
+} = require("./support/popupBoot");
+
+const MAINNET_BLOCKSCOUT = "https://eth.blockscout.com/api/v2";
+const SEPOLIA_BLOCKSCOUT = "https://eth-sepolia.blockscout.com/api/v2";
+const RECIPIENT = "0x2222222222222222222222222222222222222222";
+
+// A history entry for a send of 1 `symbol` from ADDRESS to RECIPIENT, on the
+// network with `chainId`.
+function historyEntry(hash, chainId, symbol) {
+    return {
+        hash,
+        from: ADDRESS,
+        to: RECIPIENT,
+        value: "1.0000",
+        exactValue: "1.0",
+        symbol,
+        timestamp: 1790000000,
+        isError: false,
+        direction: "sent",
+        directionLabel: "Sent",
+        contractAddress: null,
+        chainId,
+    };
+}
+
+const FIRST = historyEntry("0x" + "aa".repeat(32), "0x1", "ETH");
+const SECOND = historyEntry("0x" + "bb".repeat(32), "0x1", "ETH");
+// A transaction on Sepolia with the same hash as FIRST.
+const FIRST_ON_SEPOLIA = historyEntry(FIRST.hash, "0xaa36a7", "SepoliaETH");
+
+// The URL that asks Blockscout for `entry`, on the network it was sent on.
+function requestUrl(entry) {
+    const blockscout =
+        entry.chainId === "0x1" ? MAINNET_BLOCKSCOUT : SEPOLIA_BLOCKSCOUT;
+    return blockscout + "/transactions/" + entry.hash;
+}
+
+// What Blockscout reports for each transaction, by the URL that asks for it.
+const ANSWERS = {
+    [requestUrl(FIRST)]: {
+        block_number: 21000001,
+        nonce: 4441,
+        fee: { value: "21000000000000" },
+        raw_input: "0x11111111",
+        method: "firstMethod",
+    },
+    [requestUrl(SECOND)]: {
+        block_number: 21000002,
+        nonce: 4442,
+        fee: { value: "42000000000000" },
+        raw_input: "0x22222222",
+        method: "secondMethod",
+    },
+    [requestUrl(FIRST_ON_SEPOLIA)]: {
+        block_number: 21000003,
+        nonce: 4443,
+        fee: { value: "63000000000000" },
+        raw_input: "0x33333333",
+        method: "sepoliaMethod",
+    },
+};
+
+// The text each answer puts on screen: its block, nonce, fee, method name and
+// raw data. No text from one answer appears in another.
+const FIRST_SHOWN = [
+    "21000001",
+    "4441",
+    "0.000021 ETH",
+    "firstMethod",
+    "0x11111111",
+];
+const SECOND_SHOWN = [
+    "21000002",
+    "4442",
+    "0.000042 ETH",
+    "secondMethod",
+    "0x22222222",
+];
+const FIRST_ON_SEPOLIA_SHOWN = [
+    "21000003",
+    "4443",
+    "0.000063 SepoliaETH",
+    "sepoliaMethod",
+    "0x33333333",
+];
+
+// Everything drawn in the fields that Blockscout's answer fills.
+function drawnDetails(page) {
+    return [
+        "tx-detail-block",
+        "tx-detail-nonce",
+        "tx-detail-fee",
+        "tx-detail-calldata-action",
+        "tx-detail-rawdata",
+    ]
+        .map((id) => page.node(id).innerHTML + page.node(id).textContent)
+        .join("\n");
+}
+
+// Opens `entry` on TransactionDetail, as a history screen does.
+function open(entry) {
+    require("../src/popup/views/helpers").pushCurrentView();
+    require("../src/popup/views/transactionDetail").show(entry);
+}
+
+// The URLs of every request to Blockscout so far, in order.
+function requestedUrls() {
+    return globalThis.fetch.mock.calls.map(([url]) => url);
+}
+
+// Boots the popup on Home with "Use Blockscout" on. Blockscout answers every
+// request at once from ANSWERS, except the request for `held`. Returns the
+// page and answer(), which lets the answer for `held` land.
+async function bootWithHeldRequest(held) {
+    const page = await bootPopup(
+        unversionedValidProfile({ useBlockscout: true }),
+    );
+    let answer;
+    const heldAnswer = new Promise((resolve) => {
+        answer = resolve;
+    });
+    globalThis.fetch = jest.fn(async (url) => {
+        if (url === requestUrl(held)) await heldAnswer;
+        return { ok: true, status: 200, json: async () => ANSWERS[url] };
+    });
+    return { page, answer: () => answer() };
+}
+
+// The user opens `first`, whose request to Blockscout is held. Then the user
+// presses Back and opens `second`. Then the answer for `first` lands. Returns
+// the page.
+async function firstAnswerLandsOnSecond(first, second) {
+    const { page, answer } = await bootWithHeldRequest(first);
+    open(first);
+    await page.settle();
+    await page.click("btn-tx-back");
+    expect(page.visibleViews()).toEqual(["main"]);
+    open(second);
+    await page.settle();
+    expect(requestedUrls()).toEqual([requestUrl(first), requestUrl(second)]);
+    answer();
+    await page.settle();
+    expect(page.visibleViews()).toEqual(["transaction"]);
+    return page;
+}
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+test("an answer for the first transaction that lands on the second one's screen fills nothing", async () => {
+    const page = await firstAnswerLandsOnSecond(FIRST, SECOND);
+
+    const drawn = drawnDetails(page);
+    for (const text of SECOND_SHOWN) expect(drawn).toContain(text);
+    for (const text of FIRST_SHOWN) expect(drawn).not.toContain(text);
+});
+
+test("an answer for a hash on mainnet that lands on the same hash's screen on Sepolia fills nothing", async () => {
+    const page = await firstAnswerLandsOnSecond(FIRST, FIRST_ON_SEPOLIA);
+
+    const drawn = drawnDetails(page);
+    for (const text of FIRST_ON_SEPOLIA_SHOWN) expect(drawn).toContain(text);
+    for (const text of FIRST_SHOWN) expect(drawn).not.toContain(text);
+});
+
+test("an answer that lands while Settings is up still fills TransactionDetail", async () => {
+    const { page, answer } = await bootWithHeldRequest(FIRST);
+    open(FIRST);
+    await page.settle();
+    await page.click("btn-settings");
+    expect(page.visibleViews()).toEqual(["settings"]);
+    answer();
+    await page.settle();
+    await page.click("btn-settings");
+
+    expect(page.visibleViews()).toEqual(["transaction"]);
+    expect(requestedUrls()).toEqual([requestUrl(FIRST)]);
+    const drawn = drawnDetails(page);
+    for (const text of FIRST_SHOWN) expect(drawn).toContain(text);
+});

tests/transactions.test.js

@@ -144,6 +144,7 @@ function tokenTx(overrides = {}) {
         isError: false,
         contractAddress: USDC_CONTRACT,
         holders: 3500000,
+        chainId: "0x1",
         ...overrides,
     };
 }
@@ -259,6 +260,32 @@ describe("known-symbol spoof verification", () => {
         expect(result.newFraudContracts).toEqual([NOVEL_SPAM_CONTRACT]);
     });
 
+    // https://git.eeqj.de/sneak/AutistMask/issues/632: the bundled list holds
+    // mainnet contracts, so its symbols are not known symbols on Sepolia.
+    test("on Sepolia, a bundled symbol from another contract is kept", () => {
+        const sepoliaToken = tokenTx({
+            symbol: "USDC",
+            contractAddress: NOVEL_SPAM_CONTRACT,
+            holders: 5000000,
+            chainId: "0xaa36a7",
+        });
+        const result = filterTransactions([sepoliaToken], filters());
+        expect(result.transactions).toEqual([sepoliaToken]);
+        expect(result.newFraudContracts).toEqual([]);
+    });
+
+    test('on Sepolia, "ETH" as an ERC-20 is still spoofed', () => {
+        const fakeEth = tokenTx({
+            symbol: "ETH",
+            contractAddress: NOVEL_SPAM_CONTRACT,
+            holders: 5000000,
+            chainId: "0xaa36a7",
+        });
+        expect(filterTransactions([fakeEth], filters()).transactions).toEqual(
+            [],
+        );
+    });
+
     test("the genuine contract for that symbol is not spoofed", () => {
         const genuine = tokenTx();
         const result = filterTransactions([genuine], filters());
@@ -1495,6 +1522,41 @@ describe("fetchRecentTransactions merge and dedup", () => {
         expect(mainnet[0].chainId).toBe("0x1");
     });
 
+    // https://git.eeqj.de/sneak/AutistMask/issues/632: the bundled token list
+    // names a contract only on Ethereum Mainnet. On Sepolia, a call to the
+    // contract at USDC's mainnet address is labelled with the network's native
+    // currency. A call to any contract the wallet does not name gets that label.
+    test("a contract call on Sepolia is not named by the bundled list", async () => {
+        respondWith(
+            [
+                {
+                    hash: "0x" + "b".repeat(64),
+                    block_number: 21000095,
+                    timestamp: TS,
+                    from: { hash: VICTIM },
+                    to: { hash: USDC_CONTRACT, is_contract: true },
+                    value: "0",
+                    method: "approve",
+                    status: "ok",
+                },
+            ],
+            [],
+        );
+        const sepolia = await fetchRecentTransactions(
+            VICTIM,
+            BLOCKSCOUT,
+            "0xaa36a7",
+        );
+        expect(sepolia[0].directionLabel).toBe("Approve");
+        expect(sepolia[0].symbol).toBe("SepoliaETH");
+        const mainnet = await fetchRecentTransactions(
+            VICTIM,
+            BLOCKSCOUT,
+            "0x1",
+        );
+        expect(mainnet[0].symbol).toBe("USDC");
+    });
+
     test("the fake token transfer survives fetching and is then filtered", async () => {
         respondWith(
             [],

tests/uniswapRecipient.test.js

@@ -688,6 +688,62 @@ describe("an UNWRAP_WETH makes the output ETH only when the router holds it", ()
         ]);
     });
 
+    // The same route, then a balance check of the sender's USDC with a zero
+    // minimum. The check guarantees nothing, so Token Out stays ETH
+    // (https://git.eeqj.de/sneak/AutistMask/issues/649).
+    test("the same route, then a zero balance check of USDC, still reads as ETH with no minimum", () => {
+        const result = decode(
+            execute(
+                v4Swap(
+                    SWAP_USDT_FOR_WETH,
+                    SETTLE_USDT,
+                    take(WETH, MSG_SENDER, (ONE_WETH * 6n) / 10n),
+                    take(WETH, ADDRESS_THIS),
+                ),
+                unwrapWeth(MSG_SENDER),
+                balanceCheck(USDC, 0n),
+            ),
+        );
+        expect(result.name).toBe("Swap USDT → ETH");
+        expect(detail(result, "Token Out").value).toBe("ETH");
+        expect(labels(result)).toEqual([
+            "Protocol",
+            "Token In",
+            "Amount",
+            "Token Out",
+            "Steps",
+            "Deadline",
+        ]);
+    });
+
+    // A PERMIT2_TRANSFER_FROM moves the sender's WETH into the router. An
+    // UNWRAP_WETH pays that WETH to the user as ETH. A zero balance check of
+    // USDC sets neither Token Out nor the minimum, before the UNWRAP_WETH or
+    // after it (https://git.eeqj.de/sneak/AutistMask/issues/649).
+    test.each([
+        {
+            kind: "before the UNWRAP_WETH",
+            steps: [balanceCheck(USDC, 0n), unwrapWeth(MSG_SENDER)],
+        },
+        {
+            kind: "after the UNWRAP_WETH",
+            steps: [unwrapWeth(MSG_SENDER), balanceCheck(USDC, 0n)],
+        },
+    ])(
+        "WETH moved into the router and unwrapped, with a zero balance check of USDC $kind, reads as ETH with no minimum",
+        ({ steps }) => {
+            const result = decode(
+                execute(
+                    permit2TransferFrom(WETH, ADDRESS_THIS, ONE_WETH),
+                    ...steps,
+                ),
+            );
+            expect(detail(result, "Token Out").value).toBe("ETH");
+            expect(detail(result, "Min. received")).toBeUndefined();
+            expect(detail(result, "Min. paid out")).toBeUndefined();
+        },
+    );
+
     // A TAKE the decoder cannot read may pay part of the WETH to the user.
     test("one V4 step paying WETH to the router beside a TAKE that cannot be read, then an UNWRAP_WETH, reads as ETH with no minimum", () => {
         const result = decode(
@@ -1661,9 +1717,18 @@ describe("any token left in the router is not received", () => {
             ),
             min: "1990.0000 USDC",
         },
-        {
-            kind: "a swap paying WETH to the router, an UNWRAP_WETH into the router, then a V4 swap settling all the ETH from the router",
-            data: execute(
+    ])("$kind reads as a swap paid to the user", ({ data, min }) => {
+        const result = decode(data);
+        expect(labels(result)).toEqual(PAID_TO_USER);
+        expect(detail(result, "Min. received").value).toBe(min);
+    });
+
+    // https://git.eeqj.de/sneak/AutistMask/issues/682 — the SETTLE spends all
+    // the router's ETH, the transaction's value included, so the sender pays
+    // an amount the calldata does not state.
+    test("a swap paying WETH to the router, an UNWRAP_WETH into the router, then a V4 swap settling all the ETH from the router reads as a swap paid to the user", () => {
+        const result = decode(
+            execute(
                 swapToWeth(ADDRESS_THIS),
                 unwrapWeth(ADDRESS_THIS),
                 v4Swap(
@@ -1672,12 +1737,23 @@ describe("any token left in the router is not received", () => {
                     takeAll(USDC),
                 ),
             ),
-            min: "1990.0000 USDC",
-        },
-    ])("$kind reads as a swap paid to the user", ({ data, min }) => {
-        const result = decode(data);
-        expect(labels(result)).toEqual(PAID_TO_USER);
-        expect(detail(result, "Min. received").value).toBe(min);
+        );
+        expect(labels(result)).toEqual([
+            "Protocol",
+            "Token In",
+            "Amount",
+            "Moved from the sender",
+            "Token moved",
+            "Moved to",
+            "Token Out",
+            "Min. received",
+            "Steps",
+            "Deadline",
+        ]);
+        expect(detail(result, "Moved from the sender").value).toBe(
+            "Unknown (could not be decoded)",
+        );
+        expect(detail(result, "Min. received").value).toBe("1990.0000 USDC");
     });
 });
 
@@ -2800,17 +2876,16 @@ describe("the allow-revert flag", () => {
         },
     );
 
-    test("a BALANCE_CHECK_ERC20 with the flag, and no minimum before it, states none", () => {
+    test("a BALANCE_CHECK_ERC20 with the flag, and no minimum before it, names no output token and no minimum", () => {
         const check = balanceCheck(WETH, ONE_WETH);
         expect(detail(decode(execute(check)), "Min. paid out").value).toBe(
             "1.0000 WETH",
         );
 
         const withFlag = decode(execute(flagged(check)));
-        expect(detail(withFlag, "Token Out").address).toBe(WETH);
-        expect(detail(withFlag, "Min. paid out").value).toBe(
-            "None (no minimum guaranteed)",
-        );
+        expect(detail(withFlag, "Token Out").value).toBe(UNNAMED);
+        expect(detail(withFlag, "Min. paid out")).toBeUndefined();
+        expect(detail(withFlag, "Min. received")).toBeUndefined();
     });
 
     // Only the routers from UniversalRouterV2 on let a PERMIT2_PERMIT fail.

tests/unknownScaleSend.test.js

@@ -167,7 +167,8 @@ function row(token = {}, value = FIVE_WETH) {
 }
 
 // Fetch the explorer's rows through the real fetcher and put them exactly where
-// refreshBalances() puts them. The node reports the holding the explorer does.
+// refreshBalances() puts them on Ethereum Mainnet. The node reports the holding
+// the explorer does.
 async function fetchOnto(items) {
     mockProvider.tokenUnits = BigInt(items[0].value);
     debugFetch.mockImplementation(async () => ({
@@ -176,7 +177,7 @@ async function fetchOnto(items) {
         statusText: "OK",
         json: async () => items,
     }));
-    const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
+    const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, [], "0x1");
     state.wallets = [
         {
             name: "Wallet 1",

tests/walletDefects.test.js

@@ -357,6 +357,11 @@ describe("every way to a signature or the private key refuses a defective wallet
     });
 
     beforeEach(() => {
+        // showFlash() starts a timer that clears the message two seconds
+        // later. Each test here runs on fake timers and drops them in
+        // afterEach, so that timer never outlives the test.
+        jest.useFakeTimers();
+
         const broken = brokenXprvWallet();
         // A balance, so that no Send button's zero-balance refusal can stand
         // in for the defect check.
@@ -398,6 +403,7 @@ describe("every way to a signature or the private key refuses a defective wallet
     });
 
     afterEach(() => {
+        jest.useRealTimers();
         state.wallets = [];
         state.activeAddress = null;
         state.selectedWallet = null;