fix: give every address a row of its own, so none wraps or is shortened (closes #380) (#381)

A stored allowedSites whose value was not a list rendered a working popup and then made every subsequent save fail silently, so the user operated a wallet that persisted nothing -- worse than a blank popup, which is at least visibly broken. fraudContracts and selectedToken had the same shape: a container floored by truthiness or not at all, while its entries were dereferenced. Entries are now floored as well as containers, following the idiom #311 established, and a failed save raises a persistent banner instead of vanishing into a swallowed rejection.

The per-field justifications that used to live in a hand-written header are replaced by a contract test that drives each field's hostile and falsy values through a real popup boot, so a claim about a field answers to the code rather than to prose. Its guarantee is stated narrowly and deliberately: no structural dereference on the code paths a wholly-corrupted profile takes, which is not every path a stored record takes. The paths it does not drive are named where the claim is made, and are tracked in #379.

README.md

@@ -800,7 +800,12 @@ discoverable.
   addresses visually, as a security feature.
 - **Tailwind CSS**: Utility-first CSS via Tailwind. No custom CSS classes for
   styling. Tailwind is configured with a minimal monochrome palette. This keeps
-  the styling co-located with the markup and eliminates CSS file management.
+  the styling co-located with the markup and eliminates CSS file management. The
+  handful of classes in `styles/main.css` are not styling: `.copy-flash-*`
+  carries the copy feedback animation, and `.am-address` carries the rule that
+  an address never wraps. Both are invariants that hold in every place they
+  appear, and spelling either out as repeated utilities is how one of those
+  places drifts away from the rest.
 - **Vanilla JS**: No framework (React, Vue, Svelte, etc.). The popup UI is small
   enough that vanilla JS with simple view switching is sufficient. A framework
   would add bundle size, build complexity, and attack surface for no benefit at
@@ -849,6 +854,12 @@ that the portions still displayed will be more than adequate for the user to
 verify addresses even in the case of address spoofing attacks. Clicking an
 address will always copy the full, untruncated value.
 
+As of the address-row layout change, no view invokes that exception: every
+address in the popup is rendered on a row of its own, wide enough for all 42
+characters, and no screen truncates one to fit. The cap is still enforced in
+`truncateMiddle()` and the 32-character floor in `renderAddressHtml()`, so the
+guarantee holds for any future caller; there simply are none today.
+
 **Specific Exception — Transaction Detail view:** The transaction detail screen
 is the authoritative record of a specific transaction and shows the exact,
 untruncated amount with all meaningful decimal places (e.g. "0.00498824598498216
@@ -902,6 +913,27 @@ the swap's `Amount` and `Min. received` lines (`src/shared/uniswap.js`). An
 unbounded allowance or permit needs no scale to describe and is still shown as
 `Unlimited`.
 
+The rule holds only if nothing invents a scale UPSTREAM of it. Those three
+sources are read as authoritative, so a value written into one of them cannot be
+recognized as a guess afterwards: a fabricated `18` reads exactly like a real
+`18`, and the refusal above then never fires. So `fetchTokenBalances()` in
+`src/shared/balances.js` stores what the explorer reported or `null`, never a
+default, and the same holds for the history list's token transfers in
+`src/shared/transactions.js`. A token whose `decimals()` reverts has no scale
+anywhere, and a holding of it carries no quantity either: its balance is `null`
+— read as unknown, never as zero — and the balance list says so rather than
+printing `0.0000` for money that is really there. `0` is a real scale and is
+never treated as absent.
+
+`tokenBalances[].decimals` is therefore the explorer's own answer and nothing
+else, which is not the same question as the scale a screen should render at.
+Anything that needs the second one calls `resolveTokenDecimals()` — the balance
+list, the approval and swap lines, and the Send screen, which carries the
+resolved scale onto the pending transaction for `transferAmount.js` to encode
+and compare against. Reading the stored field directly instead answers `null`
+for a bundled or tracked token the explorer merely omitted, which is not a
+refusal the wallet has any reason to make.
+
 #### Partial USD totals
 
 Prices are fetched for the top 25 tokens only, so an address can hold assets the
@@ -1015,17 +1047,49 @@ saved data cannot be read and that nothing was signed or sent, rather than the
 generic `-32603` every request used to answer.
 
 Every other field of the record is floored in `normalizePersisted()` rather than
-gated. That floor is a type check for the fields something dereferences
-structurally — `trackedTokens`, each address's `tokenBalances`, `networkId`,
-`networkEndpoints`, `activeAddress`, `viewStack` — and it checks the ENTRIES as
-well as the container, because `[1, 2]` is a list and `t.address` is one level
-below an `Array.isArray()`. The remaining fields get a `saved.x || default` or a
-present-or-default passthrough that takes the stored value verbatim, with no
-type check at all; which field is in which category is listed in the header of
-`src/shared/stateSchema.js`. A truthy value of the wrong type in a field that IS
-dereferenced walks through truthiness and throws on the first read, which is the
-blank popup again by a longer route — so adding a field means choosing between
-the two by what reads it.
+gated, and the floor is not the same for every field. Some are type-checked as a
+container AND entry by entry, because `[1, 2]` is a list, `{"0x…": "notalist"}`
+is an object, and the dereference is one level below the container check; a
+malformed entry is dropped, except in `networkEndpoints`, where the entry is
+coerced so an unknown network's endpoints are not lost, and in `viewStack`,
+where the stack is truncated at the first entry the popup will not reopen onto.
+Some are type-checked as a scalar. The rest take the stored value verbatim,
+because nothing dereferences them structurally.
+
+Which field is which is not written in prose anywhere, deliberately.
+`tests/persistedFieldContract.test.js` is the list: one row per persisted field,
+naming the property that field's floor is claimed to have and proving it by
+driving the real code with hostile values — and, for every field whose only
+defence is that nothing dereferences it, by booting the real popup entry point
+over that value onto every view the popup can reopen onto. That last part is
+what makes the claim falsifiable, because this defect class lives on the restore
+path rather than on the home screen. Read the claim narrowly, as that file
+states it: what those boots prove is no structural dereference on the code paths
+a WHOLLY-CORRUPTED PROFILE takes, which is not every path a stored record takes.
+Not driven: any pairing of values the four slots do not produce, a view only
+forward navigation opens, anything behind a click, and everything a healthy
+profile reaches. Within that boundary the verdict is unconditional — if one of
+those boots leaves the popup unhealthy or off the view it stored, `make check`
+fails, including when it takes two corrupted fields at once, because the verdict
+is the combined boot and the per-field re-boot that names a culprit can only
+decorate the message. So does a field that gains a floor while its row still
+claims it has none, and so does a field added to `PERSISTED_FIELDS` with no row
+at all. The per-field justification that used to live in the header of
+`src/shared/stateSchema.js` shipped a false claim in three consecutive changes,
+each caught only by a reviewer re-deriving thirty fields by hand.
+
+The `allowedSites` case is why the entry check is not optional. A stored
+`{"0x…": "notalist"}` is a well-formed object holding a malformed entry: it
+passed the gate, rendered a completely healthy popup, and then threw inside
+`saveState()`'s per-hostname merge, so every save from that moment on failed and
+the user went on operating a wallet that was persisting nothing
+([#362](https://git.eeqj.de/sneak/AutistMask/issues/362)). A save that fails is
+now also reported rather than swallowed: `onSaveFailure()` in
+`src/shared/state.js` is called for every failed save, awaited or not, and the
+popup puts up a persistent "NOT SAVED" banner (`showSaveFailureBanner()` in
+`src/popup/views/helpers.js`). Storage can still fail for reasons no floor
+covers — a quota, a revoked permission, a record a newer build wrote — and the
+wallet must never look healthy while that is true.
 
 The `networkId` check is not cosmetic: that value is an object KEY into
 `state.networkEndpoints`, so an unvalidated `"__proto__"` would set the map's
@@ -1080,6 +1144,14 @@ than only unhiding it, through the same dispatch and data guards as the restore
 (`src/popup/viewRouter.js`), and falls back to Home when the state the target
 would render is gone.
 
+Those data guards check the ENTRIES of the stored `viewData`, not just the one
+field each branch gates on, and the same goes for `selectedWallet` and
+`selectedAddress`. `restoreView()` is not inside a `try`, so a `TypeError` in a
+renderer skips the rest of popup init and leaves the user with no view, no
+message and no control — the same blank popup by a longer route. Anything the
+restore path dereferences is therefore either floored in `normalizePersisted()`
+or refused by the guard, and the screen falls back to Home instead.
+
 It renders only a screen this page load has not rendered yet. Forward navigation
 renders as it goes, and `viewRouter.js` records every screen that reaches
 `showView()`, so "Back" onto a screen already on the page unhides it and nothing
@@ -1121,13 +1193,17 @@ view would leave a wallet one click from deletion.
     - Send / Receive quick-action buttons, both acting on the active address
     - ETH/USD price display
     - Wallet list: each wallet shows its name (tap to rename inline) and a "+"
-      button for HD and xprv wallets, then one block per address with "Address
-      N" (bold when active), the ENS name if resolved, the full address, an
-      `[info]` button, an `[x]` button (only on HD and xprv wallets holding more
-      than one address), the address USD total, and a balance line for ETH and
-      for each token shown for that address
+      button for HD and xprv wallets, then one block per address. The block
+      opens with a row carrying the colour dot, "Address N" (bold when active),
+      an `[info]` button and an `[x]` button (only on HD and xprv wallets
+      holding more than one address); the ENS name, if resolved, is below it;
+      then the full address on a row of its own, followed by the address USD
+      total and a balance line for ETH and for each token shown for that address
     - "Recent Transactions": up to 25 transactions merged across every address
-      of every wallet, deduplicated by hash and filtered
+      of every wallet, deduplicated by hash and filtered. Each row is three
+      lines: age and direction, then the counterparty's colour dot (with our own
+      name for it, where it is one of our addresses) and the amount, then the
+      counterparty's full address on a row of its own
     - "Add additional wallet..." link at bottom
 - **Transitions**:
     - Tap address row → sets the active address and broadcasts

TODO.md

@@ -45,6 +45,96 @@ but the review is broader than any of them.
 
 # Completed Steps
 
+- 2026-08-30: An address no longer wraps, or is shortened to fit, in any of the
+  common views ([#380](https://git.eeqj.de/sneak/AutistMask/issues/380)). The
+  wallet list was the reported case: the address shared one row with the
+  `[info]` and `[x]` controls and folded onto a second line, which turns one
+  42-character string the user is meant to compare into two shorter ones — the
+  shape an address-poisoning attack wants. The fix is layout, not CSS: every
+  address in the popup now sits alone on a full-width row, with the colour dot,
+  the wallet title, the ENS name and the explorer link moved onto a strip above
+  it, and the transaction rows carry the counterparty's whole address instead of
+  a `truncateMiddle()`d one squeezed in beside the amount. `truncateMiddle()`
+  keeps its 10-character cap and its 32-character floor moved into
+  `renderAddressHtml()`, so the guarantee outlives having no callers. The e2e
+  suite measures every rendered address in a real Chromium — whole, one line
+  box, inside its row and inside the popup — across Home, the address, token,
+  receive, send and transaction detail screens, the confirmation screen and the
+  dApp transaction prompt.
+- 2026-08-23: Both manifests declare toolbar icons, and real PNGs at
+  16/32/48/128 ship inside both archives
+  ([#371](https://git.eeqj.de/sneak/AutistMask/issues/371)). Neither manifest
+  had an `icons` block, so both browsers drew a generic puzzle piece — the first
+  thing the owner sees on every launch, and how a user tells a real extension
+  from a look-alike. The sizes `build.js` copies into each browser directory are
+  read out of the manifest that ships next to them rather than from a second
+  list, so a declared size `icons/` does not hold fails `make build`;
+  `script/lib/package.js` already resolves `.png` references, so an icon that
+  reached a manifest but not the archive fails packaging. The artwork is
+  original: a flat dark-navy rounded field with a teal triangular "A", drawn
+  from geometry and rasterised into PNG, nothing traced or downloaded.
+- 2026-08-23: A persisted container whose ENTRIES were dereferenced unchecked no
+  longer reaches a `.map()` or a `.toLowerCase()`
+  ([#362](https://git.eeqj.de/sneak/AutistMask/issues/362)). `allowedSites` was
+  the worst shape available: a stored `{"0x…": "notalist"}` passed the gate,
+  rendered a completely healthy popup, and then threw inside `saveState()`'s
+  per-hostname merge, so every save from that moment on failed silently and the
+  user went on operating a wallet that was persisting nothing — measured as
+  `chrome.storage.local.set` never being called at all. `deniedSites` has the
+  same shape, `fraudContracts` the same class with a milder consequence, and the
+  sweep for the class turned up `selectedToken`, `rpcUrl` (handed whole to
+  `new JsonRpcProvider()`, which throws synchronously outside any `try`), the
+  entries of `viewData` (four restore branches gate on one truthy field and then
+  dereference an address), and `selectedWallet`/`selectedAddress` (a stored
+  `"map"` is TRUTHY against a real Array, so the restore guard does not
+  short-circuit). All of them are now floored in `src/shared/persistedState.js`
+  or refused by the per-branch guards in `src/popup/viewRouter.js`. Separately,
+  a save that fails is no longer swallowed: `onSaveFailure()` in
+  `src/shared/state.js` reports every failed save, awaited or not, and the popup
+  raises a persistent "NOT SAVED" banner. The hand-written per-field
+  justification in the header of `src/shared/stateSchema.js` — which had shipped
+  a false claim in three consecutive changes — is replaced by
+  `tests/persistedFieldContract.test.js`, one row per persisted field, each
+  proven by driving the real code with hostile values — and, for a field whose
+  only defence is that nothing dereferences it, by booting the real popup entry
+  point over that value onto every view the popup can reopen onto, since that is
+  the path this whole class of defect lives on. Each such field is driven at
+  both polarities — a value nothing writes is wrong-typed and so truthy, so a
+  falsy slot is driven too, or the field is proven unable to be falsy after the
+  floor. The claim is narrow and stated as such: no structural dereference on
+  the code paths a wholly-corrupted profile takes, which is not every path a
+  stored record takes — a pairing of values the four slots do not produce, a
+  view only forward navigation opens, anything behind a click, and everything a
+  healthy profile reaches are all undriven. Within that boundary the verdict is
+  unconditional, including a dereference that takes two corrupted fields at
+  once, since the assertion is on the combined boot and the per-field re-boot
+  can only decorate the message. A field with no row and a field that gains a
+  floor while its row still claims it has none also fail `make check`.
+- 2026-08-23: A swap amount and the token it is counted in now always come from
+  the same hop, on both sides of the approval screen
+  ([#359](https://git.eeqj.de/sneak/AutistMask/issues/359) and
+  [#364](https://git.eeqj.de/sneak/AutistMask/issues/364), the output and input
+  halves of one gate, fixed as one unit). `src/shared/uniswap.js` gated the
+  token and the amount on truthiness and independently; an address is never
+  falsy once set but an amount of `0n` is, so a hop supplying a zero amount
+  fixed the token and left the amount open, and the next hop's figure was then
+  rendered against the first hop's token at that token's scale — 0.5 WETH shown
+  as `500000000000.0000 USDT`, and an earlier hop's `Min. received` shown for a
+  final leg that guarantees nothing. Both sides are now set as a pair through
+  explicit presence, a zero slippage floor reads `None (no minimum guaranteed)`,
+  and V4's `OPEN_DELTA` (an `amountIn` of zero, which `V4Router` reads as "swap
+  the whole open credit") reads `All available (V4 open delta)` instead of
+  `0.0000`.
+- 2026-08-23: A swap whose input token the calldata never named is said to be
+  unknown instead of being called ETH
+  ([#357](https://git.eeqj.de/sneak/AutistMask/issues/357)), the twin on the
+  input side of [#353](https://git.eeqj.de/sneak/AutistMask/issues/353). A null
+  `inputToken` rendered as `Token In: ETH (native)` and titled the swap
+  `Swap ETH -> X`, asserting the user was paying native ETH when nothing in the
+  calldata said so. The null-means-ETH collapse is now gone from `tokenInfo()`
+  itself rather than guarded at each call site: null is refused, and native ETH
+  keeps arriving as the explicit zero address that `WRAP_ETH` and V4's
+  `Currency.wrap(address(0))` both use.
 - 2026-08-23: A swap whose output token the calldata never named is said to be
   unknown instead of being called ETH
   ([#353](https://git.eeqj.de/sneak/AutistMask/issues/353)). `tokenInfo(null)`
@@ -97,6 +187,46 @@ but the review is broader than any of them.
   `src/shared/restorableViews.js`, since `persistedState.js` requires it and
   that module is in the background bundle.
 
+- 2026-08-23: An explorer that reports no `decimals` for a token no longer has a
+  scale invented for it before storage
+  ([#349](https://git.eeqj.de/sneak/AutistMask/issues/349)).
+  `fetchTokenBalances()` did `parseInt(item.token.decimals || "18", 10)` on the
+  way in, so a token whose `decimals()` reverts was written to
+  `tokenBalances[].decimals` as a fabricated `18` that no reader could tell from
+  a real one. That is upstream of the resolve-or-refuse rule
+  ([#306](https://git.eeqj.de/sneak/AutistMask/issues/306),
+  [#340](https://git.eeqj.de/sneak/AutistMask/issues/340)): both approval paths
+  read this stored value as an authoritative source, so the guess walked past
+  refusals that were intact and simply never fired. The stored value is now the
+  explorer's own answer or `null`, and both the ERC-20 amount line and the swap
+  lines reach `unknownDecimalsAmount()` on it. The history list's token
+  transfers carried the same `|| "18"` and now state base units with the scale
+  unknown rather than a quantity. A holding whose scale nothing knows carries
+  `balance: null` — unknown, not zero — and the balance list, the USD total, the
+  Send screen and the confirmation screen each say so instead of printing
+  `0.0000` for money that is really there. The uint8 check is one shared
+  `toDecimals()` rather than three copies, and it answers `0` for a real scale
+  of zero: `|| "18"` collapsed that to eighteen, the trap of
+  [#246](https://git.eeqj.de/sneak/AutistMask/issues/246). Existing installs
+  hold `18`s that cannot be told apart retroactively; they display exactly as
+  they do today until the next balance refresh, which rewrites `tokenBalances`
+  wholesale and needs no user action. No `|| 18` or `?? 18` fallback remains
+  anywhere in `src/`; the literal `18`s that do remain are real data, not
+  defaults — 432 per-token `decimals: 18` entries in the bundled
+  `src/shared/tokenList.js`, and, outside that file, only native ETH's
+  protocol-defined scale in `src/shared/uniswap.js` and the fixed-point
+  comparison scale in `src/shared/txValidation.js`. `tokenBalances[].decimals`
+  is the explorer's answer alone and not the scale a screen renders at, so the
+  Send screen resolves through `resolveTokenDecimals()` like every other
+  consumer: reading the stored field raw carried a `null` into `estimateGas()`
+  for a bundled token such as WETH, which reported an unestimable network fee
+  and left Send disabled behind a message no retry could clear. Send resolves
+  with `wallets`, which adds the cross-address disagreement check the balance
+  list does not make, so the two can differ; where they do, the stored quantity
+  was computed at a scale Send has refused, and it is withdrawn with it. An
+  unknown scale is an unknown balance, and the user is told that rather than
+  that the fee could not be estimated.
+
 - 2026-08-23: The background no longer reads or writes the shared `state`
   singleton ([#324](https://git.eeqj.de/sneak/AutistMask/issues/324)), which
   also closes the cold-worker wrong-chain send

build.js

@@ -51,6 +51,17 @@ const RECEIPT_ENV = "AUTISTMASK_BUILD_RECEIPT";
 // rather than writing a receipt that cannot be checked.
 const SAFE_EMITTED_PATH = /^dist\/[A-Za-z0-9._][A-Za-z0-9._/-]*$/;
 
+// Where each browser directory's manifest comes from, and — through its
+// "icons" — which image files ship inside that directory.
+const MANIFEST_SOURCES = new Map([
+    [DIST_CHROME, path.join(__dirname, "manifest", "chrome.json")],
+    [DIST_FIREFOX, path.join(__dirname, "manifest", "firefox.json")],
+]);
+
+// What an "icons" entry may name: a plain file under icons/, so a manifest
+// value is never joined into a path that leaves the repo.
+const ICON_REF_RE = /^icons\/[A-Za-z0-9._-]+\.png$/;
+
 function ensureDir(dir) {
     fs.mkdirSync(dir, { recursive: true });
 }
@@ -257,6 +268,42 @@ function copyEmitted(src, dest) {
     recordEmitted(dest);
 }
 
+// Copy the icons one browser directory ships. The sizes come from the manifest
+// that will sit next to them, not from a second list here: a size the manifest
+// declares and icons/ does not hold fails the build, rather than shipping a
+// manifest whose reference resolves to nothing. Relative to the browser
+// directory, so nothing points up and out of it the way dist/styles.css does.
+function copyIcons(distDir) {
+    const manifestPath = MANIFEST_SOURCES.get(distDir);
+    const manifest = JSON.parse(fs.readFileSync(manifestPath, "utf8"));
+    const refs = Object.values(manifest.icons || {});
+    if (refs.length === 0) {
+        throw new Error(
+            `${repoRelative(manifestPath)} declares no icons, so the browser ` +
+                `renders a generic placeholder for this extension`,
+        );
+    }
+    for (const ref of refs) {
+        if (!ICON_REF_RE.test(ref)) {
+            throw new Error(
+                `${repoRelative(manifestPath)} declares icon ` +
+                    `${JSON.stringify(ref)}, which is not a plain file under ` +
+                    `icons/`,
+            );
+        }
+        const src = path.join(__dirname, ref);
+        if (!fs.existsSync(src)) {
+            throw new Error(
+                `${repoRelative(manifestPath)} declares ${ref}, which is not ` +
+                    `in this tree`,
+            );
+        }
+        const dest = path.join(distDir, ref);
+        ensureDir(path.dirname(dest));
+        copyEmitted(src, dest);
+    }
+}
+
 function sha256File(absPath) {
     return crypto
         .createHash("sha256")
@@ -524,6 +571,8 @@ async function build() {
             tailwindOutput,
             path.join(distDir, "src", "popup", "styles.css"),
         );
+
+        copyIcons(distDir);
     }
 
     // copy manifests

manifest/chrome.json

@@ -9,6 +9,12 @@
     "content_security_policy": {
         "extension_pages": "default-src 'self'; script-src 'self' 'wasm-unsafe-eval'; object-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; connect-src 'self' https: http:; frame-src 'none'; form-action 'none'; base-uri 'none'"
     },
+    "icons": {
+        "16": "icons/icon16.png",
+        "32": "icons/icon32.png",
+        "48": "icons/icon48.png",
+        "128": "icons/icon128.png"
+    },
     "action": {
         "default_popup": "src/popup/index.html"
     },

manifest/firefox.json

@@ -5,6 +5,12 @@
     "description": "Minimal Ethereum wallet for Firefox",
     "permissions": ["storage", "activeTab", "alarms", "<all_urls>"],
     "content_security_policy": "default-src 'self'; script-src 'self' 'wasm-unsafe-eval'; object-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; connect-src 'self' https: http:; frame-src 'none'; form-action 'none'; base-uri 'none'",
+    "icons": {
+        "16": "icons/icon16.png",
+        "32": "icons/icon32.png",
+        "48": "icons/icon48.png",
+        "128": "icons/icon128.png"
+    },
     "browser_action": {
         "default_popup": "src/popup/index.html"
     },

src/popup/index.html

@@ -213,10 +213,7 @@
                 </div>
 
                 <!-- active address display -->
-                <div
-                    id="active-address-display"
-                    class="text-xs break-all mb-3"
-                ></div>
+                <div id="active-address-display" class="text-xs mb-3"></div>
 
                 <!-- quick actions for active address -->
                 <div class="flex gap-2 mb-2">
@@ -292,7 +289,7 @@
                     class="font-bold mb-1 hidden flex items-center"
                 ></div>
                 <div
-                    class="text-xs mb-1 cursor-pointer break-all"
+                    class="text-xs mb-1 cursor-pointer"
                     title="Click to copy"
                     id="address-line"
                 >
@@ -380,14 +377,14 @@
                 ></div>
                 <h2 class="font-bold mb-1">Export Private Key</h2>
                 <p class="text-xs mb-1" id="export-privkey-title"></p>
-                <p class="text-xs mb-3">
+                <div class="text-xs mb-3">
                     <span id="export-privkey-dot"></span>
                     <span
                         id="export-privkey-address"
                         class="cursor-pointer"
                         title="Click to copy"
                     ></span>
-                </p>
+                </div>
                 <p class="text-xs mb-3 text-muted">
                     Warning: anyone with this private key can access and
                     transfer all funds from this address. Never share it.
@@ -440,7 +437,7 @@
                 </div>
 
                 <div
-                    class="text-xs mb-1 cursor-pointer break-all"
+                    class="text-xs mb-1 cursor-pointer"
                     title="Click to copy"
                     id="address-token-line"
                 >
@@ -573,19 +570,16 @@
                 <!-- ERC-20 token contract (hidden for ETH) -->
                 <div id="confirm-token-section" class="mb-3 hidden">
                     <div class="text-xs text-muted mb-1">Token contract</div>
-                    <div
-                        id="confirm-token-contract"
-                        class="text-xs break-all"
-                    ></div>
+                    <div id="confirm-token-contract" class="text-xs"></div>
                 </div>
 
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">From</div>
-                    <div id="confirm-from" class="text-xs break-all"></div>
+                    <div id="confirm-from" class="text-xs"></div>
                 </div>
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">To</div>
-                    <div id="confirm-to" class="text-xs break-all"></div>
+                    <div id="confirm-to" class="text-xs"></div>
                     <div
                         id="confirm-to-ens"
                         class="text-xs text-muted hidden"
@@ -728,7 +722,7 @@
                 </div>
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">To</div>
-                    <div id="wait-tx-to" class="text-xs break-all"></div>
+                    <div id="wait-tx-to" class="text-xs"></div>
                 </div>
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">Transaction hash</div>
@@ -747,7 +741,7 @@
                 </div>
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">To</div>
-                    <div id="success-tx-to" class="text-xs break-all"></div>
+                    <div id="success-tx-to" class="text-xs"></div>
                 </div>
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">Block</div>
@@ -774,7 +768,7 @@
                 </div>
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">To</div>
-                    <div id="error-tx-to" class="text-xs break-all"></div>
+                    <div id="error-tx-to" class="text-xs"></div>
                 </div>
                 <div class="mb-3">
                     <div
@@ -811,9 +805,9 @@
                     <canvas id="receive-qr"></canvas>
                 </div>
                 <div
-                    class="border border-border p-2 break-all mb-3 text-xs cursor-pointer"
+                    class="border border-border p-2 mb-3 text-xs cursor-pointer"
                 >
-                    <span id="receive-address-block" class="select-all"></span>
+                    <div id="receive-address-block" class="select-all"></div>
                     <span id="receive-etherscan-link"></span>
                 </div>
                 <button
@@ -1239,7 +1233,7 @@
                 </p>
                 <div
                     id="delete-address-value"
-                    class="text-xs mb-2 break-all min-h-[1rem]"
+                    class="text-xs mb-2 min-h-[1rem]"
                 ></div>
                 <div
                     class="text-xs mb-2 border border-border border-dashed p-2"
@@ -1429,14 +1423,11 @@
                     </div>
                     <div class="mb-2">
                         <div class="text-xs text-muted mb-1">From</div>
-                        <div
-                            id="tx-detail-from"
-                            class="text-xs break-all"
-                        ></div>
+                        <div id="tx-detail-from" class="text-xs"></div>
                     </div>
                     <div class="mb-2">
                         <div class="text-xs text-muted mb-1">To</div>
-                        <div id="tx-detail-to" class="text-xs break-all"></div>
+                        <div id="tx-detail-to" class="text-xs"></div>
                     </div>
                 </div>
 
@@ -1473,7 +1464,7 @@
                         </div>
                         <div
                             id="tx-detail-token-contract"
-                            class="text-xs break-all"
+                            class="text-xs"
                         ></div>
                     </div>
                 </div>
@@ -1567,11 +1558,11 @@
 
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">From</div>
-                    <div id="approve-tx-from" class="text-xs break-all"></div>
+                    <div id="approve-tx-from" class="text-xs"></div>
                 </div>
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">Contract</div>
-                    <div id="approve-tx-to" class="text-xs break-all"></div>
+                    <div id="approve-tx-to" class="text-xs"></div>
                 </div>
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">Value</div>
@@ -1673,7 +1664,7 @@
 
                 <div class="mb-3">
                     <div class="text-xs text-muted mb-1">From</div>
-                    <div id="approve-sign-from" class="text-xs break-all"></div>
+                    <div id="approve-sign-from" class="text-xs"></div>
                 </div>
 
                 <div class="mb-3">

src/popup/index.js

@@ -1,9 +1,14 @@
 // AutistMask popup entry point.
 // Loads state, initializes views, triggers first render.
 
-const { state, saveState, loadState } = require("../shared/state");
+const {
+    state,
+    saveState,
+    onSaveFailure,
+    loadState,
+} = require("../shared/state");
 const { StateUnusableError } = require("../shared/stateSchema");
-const { setRuntimeDebug } = require("../shared/log");
+const { log, setRuntimeDebug } = require("../shared/log");
 const { refreshPrices } = require("../shared/prices");
 const { refreshBalances } = require("../shared/balances");
 const {
@@ -11,6 +16,7 @@ const {
     showView,
     updateDebugBanner,
     setBackRenderer,
+    showSaveFailureBanner,
     pushCurrentView,
     goBack,
 } = require("./views/helpers");
@@ -61,6 +67,14 @@ async function doRefreshAndRender() {
         state.lastBalanceRefresh = Date.now();
         await saveState();
         renderWalletList();
+    } 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.
+        log.errorf("popup: background refresh failed:", e);
     } finally {
         refreshInFlight = false;
     }
@@ -136,6 +150,12 @@ function fallbackView() {
 }
 
 async function init() {
+    // First, before anything can save: showView() saves on every navigation
+    // without awaiting, so a save that fails from here on has somewhere to be
+    // reported rather than being swallowed by the save queue
+    // (https://git.eeqj.de/sneak/AutistMask/issues/362). Registered ahead of
+    // the approval-window branch below too, since that window saves as well.
+    onSaveFailure(showSaveFailureBanner);
     try {
         await loadState();
     } catch (e) {

src/popup/styles/main.css

@@ -44,3 +44,23 @@ body {
         background-color 225ms ease-out,
         color 225ms ease-out;
 }
+
+/* An address is one atomic string, so it gets a row of its own and never
+ * breaks across lines. A wrapped address reads as two shorter strings, and
+ * two shorter strings are exactly what an address-poisoning attack needs
+ * the user to compare instead of the whole thing. Every view that shows an
+ * address puts it in one of these, alone: the colour dot, the wallet title,
+ * the ENS name and the explorer link all live on their own line above, so
+ * nothing competes with the 42 characters for width.
+ *
+ * overflow-x is the escape hatch, not the mechanism. The row is wide enough
+ * for a full address at every nesting depth the popup uses; if that ever
+ * stops being true — a font with wider glyphs, a browser zoom — the row
+ * scrolls and the user can still reach the last character, rather than the
+ * tail being clipped away by #app's overflow-x-hidden with nothing to say
+ * it happened. tests/e2e asserts the scroll is never actually needed. */
+.am-address {
+    display: block;
+    white-space: nowrap;
+    overflow-x: auto;
+}

src/popup/viewRouter.js

@@ -53,12 +53,17 @@ function resetRenderedViews() {
 const ALWAYS_RENDER_ON_BACK = new Set(["main"]);
 
 // Views that render an address the user picked and cannot be rendered
-// without one.
+// without one. "confirm-tx" is here because its Sign button dereferences
+// `state.wallets[state.selectedWallet].encryptedSecret`
+// (src/popup/views/confirmTx.js) behind no guard of its own — a screen that
+// can only throw when the user presses its one button must not be restored
+// onto.
 const ADDRESS_VIEWS = new Set([
     "address",
     "address-token",
     "receive",
     "transaction",
+    "confirm-tx",
 ]);
 
 function needsAddress(view) {
@@ -74,6 +79,73 @@ function hasValidAddress(state) {
     );
 }
 
+// The stored viewData ENTRIES each branch below dereferences, as opposed to
+// the one field it gates on.
+//
+// A gate on a single truthy field checks the container, not the entries, and
+// the dereference is one level below it: a stored `{"currentView":
+// "success-tx","viewData":{"hash":"0x1"}}` passes `data.hash` and then throws
+// on `address.toLowerCase()` inside addressTitle() (src/popup/views/
+// helpers.js), out of restoreView(), which src/popup/index.js does not guard —
+// so the rest of popup init never runs. txStatus.restoreWait() has checked its
+// own branch's fields since it was written; these are the other four.
+//
+// Only what actually throws is required. Fields that are compared,
+// concatenated or escaped coerce (escapeHtml() and displaySymbol() both
+// String() their argument), so requiring them would refuse a restorable screen
+// over a cosmetic value.
+function isText(value) {
+    return typeof value === "string";
+}
+
+function isRecord(value) {
+    return typeof value === "object" && value !== null && !Array.isArray(value);
+}
+
+// An address handed to renderAddressHtml()/addressTitle(): both reach
+// `address.slice()` and `address.toLowerCase()` with no guard.
+function isAddressText(value) {
+    return isText(value);
+}
+
+// Decoded calldata, as decodedDetailsHtml() (src/popup/views/txStatus.js)
+// walks it: `for (const d of decoded.details)` needs an iterable, and each
+// entry's `address` reaches toAddressHtml(). Absent or falsy is the ordinary
+// case and short-circuits before either.
+function isRenderableDecoded(value) {
+    if (!value) return true;
+    if (!isRecord(value)) return false;
+    if (!value.details) return true;
+    if (!Array.isArray(value.details)) return false;
+    return value.details.every(
+        (entry) =>
+            isRecord(entry) && (!entry.address || isAddressText(entry.address)),
+    );
+}
+
+// The pending transaction confirmTx.show() renders: `token` reaches
+// renderAddressHtml() when it is not "ETH", and `from`/`to` reach
+// addressTitle(), makeBlockie() and getLocalWarnings().
+function isRenderablePendingTx(value) {
+    return (
+        isRecord(value) &&
+        isText(value.token) &&
+        isAddressText(value.from) &&
+        isAddressText(value.to)
+    );
+}
+
+// The stored transaction transactionDetail.render() shows. contractAddress is
+// optional on an ETH transfer, and reaches addressDotHtml() when it is there.
+function isRenderableTx(value) {
+    return (
+        isRecord(value) &&
+        isAddressText(value.from) &&
+        isAddressText(value.to) &&
+        (!value.contractAddress || isAddressText(value.contractAddress))
+    );
+}
+
 // Render `view` from persisted state. Each view module shows itself, so a
 // true return means the view is both rendered and on screen.
 //
@@ -107,11 +179,11 @@ function renderView(view, state, views) {
             views.settingsAddToken.show();
             return true;
         case "confirm-tx":
-            if (!data.pendingTx) return false;
+            if (!isRenderablePendingTx(data.pendingTx)) return false;
             views.confirmTx.restore();
             return true;
         case "transaction":
-            if (!data.tx) return false;
+            if (!isRenderableTx(data.tx)) return false;
             views.transactionDetail.render();
             return true;
         case "wait-tx":
@@ -120,10 +192,13 @@ function renderView(view, state, views) {
             return Boolean(views.txStatus.restoreWait());
         case "success-tx":
             if (!data.hash) return false;
+            if (!isAddressText(data.to)) return false;
+            if (!isRenderableDecoded(data.decoded)) return false;
             views.txStatus.renderSuccess();
             return true;
         case "error-tx":
             if (!data.message) return false;
+            if (!isAddressText(data.to)) return false;
             views.txStatus.renderError();
             return true;
         default:

src/popup/views/addressDetail.js

@@ -7,7 +7,6 @@ const {
     addressTitle,
     escapeHtml,
     displaySymbol,
-    truncateMiddle,
     renderAddressHtml,
     attachCopyHandlers,
     goBack,
@@ -229,10 +228,12 @@ function renderTransactions(txs) {
         const amountStr = tx.value
             ? escapeHtml(tx.value + " " + sym)
             : escapeHtml(sym);
-        const maxAddr = Math.max(32, 36 - Math.max(0, amountStr.length - 10));
-        const displayAddr =
-            title || ensName || truncateMiddle(counterparty, maxAddr);
-        const addrStr = escapeHtml(displayAddr);
+        // The counterparty used to be squeezed in beside the amount and
+        // truncated to whatever was left over. It gets its own row now and
+        // is shown whole; the title or ENS name, where there is one, names
+        // it on the line above rather than replacing it.
+        const nameStr = escapeHtml(title || ensName || "");
+        const addrStr = escapeHtml(counterparty);
         const dot = addressDotHtml(counterparty);
         const err = tx.isError ? " (failed)" : "";
         const opacity = tx.isError ? " opacity:0.5;" : "";
@@ -240,7 +241,8 @@ function renderTransactions(txs) {
         const iso = escapeHtml(isoDate(tx.timestamp));
         html += `<div class="tx-row py-2 border-b border-border-light text-xs cursor-pointer hover:bg-hover" data-tx="${i}" style="${opacity}">`;
         html += `<div class="flex justify-between"><span class="text-muted" title="${iso}">${ago}</span><span>${dirLabel}${err}</span></div>`;
-        html += `<div class="flex justify-between"><span class="flex items-center">${dot}${addrStr}</span><span>${amountStr}</span></div>`;
+        html += `<div class="flex justify-between"><span class="flex items-center">${dot}${nameStr}</span><span>${amountStr}</span></div>`;
+        html += `<div class="am-address">${addrStr}</div>`;
         html += `</div>`;
         i++;
     }

src/popup/views/addressToken.js

@@ -10,8 +10,8 @@ const {
     addressTitle,
     escapeHtml,
     displaySymbol,
-    truncateMiddle,
     balanceLine,
+    unknownableAmount,
     renderAddressHtml,
     attachCopyHandlers,
     goBack,
@@ -118,7 +118,9 @@ function show() {
             addr.tokenBalances,
             state.trackedTokens,
         );
-        amount = tb ? parseFloat(tb.balance || "0") : 0;
+        // null when the scale is unknown: no quantity to show, and none to
+        // price. balanceLine() states that rather than printing 0.0000.
+        amount = tb ? unknownableAmount(tb.balance) : 0;
         price = getPrice(symbol);
     }
 
@@ -152,7 +154,7 @@ function show() {
     attachCopyHandlers($("address-token-line"));
 
     // USD total for this token only
-    const usdVal = price ? amount * price : null;
+    const usdVal = price && amount !== null ? amount * price : null;
     const usdStr = formatUsd(usdVal);
     $("address-token-usd-total").innerHTML = usdStr || " ";
 
@@ -302,10 +304,12 @@ function renderTransactions(txs) {
         const amountStr = tx.value
             ? escapeHtml(tx.value + " " + sym)
             : escapeHtml(sym);
-        const maxAddr = Math.max(32, 36 - Math.max(0, amountStr.length - 10));
-        const displayAddr =
-            title || ensName || truncateMiddle(counterparty, maxAddr);
-        const addrStr = escapeHtml(displayAddr);
+        // The counterparty used to be squeezed in beside the amount and
+        // truncated to whatever was left over. It gets its own row now and
+        // is shown whole; the title or ENS name, where there is one, names
+        // it on the line above rather than replacing it.
+        const nameStr = escapeHtml(title || ensName || "");
+        const addrStr = escapeHtml(counterparty);
         const dot = addressDotHtml(counterparty);
         const err = tx.isError ? " (failed)" : "";
         const opacity = tx.isError ? " opacity:0.5;" : "";
@@ -313,7 +317,8 @@ function renderTransactions(txs) {
         const iso = escapeHtml(isoDate(tx.timestamp));
         html += `<div class="tx-row py-2 border-b border-border-light text-xs cursor-pointer hover:bg-hover" data-tx="${i}" style="${opacity}">`;
         html += `<div class="flex justify-between"><span class="text-muted" title="${iso}">${ago}</span><span>${dirLabel}${err}</span></div>`;
-        html += `<div class="flex justify-between"><span class="flex items-center">${dot}${addrStr}</span><span>${amountStr}</span></div>`;
+        html += `<div class="flex justify-between"><span class="flex items-center">${dot}${nameStr}</span><span>${amountStr}</span></div>`;
+        html += `<div class="am-address">${addrStr}</div>`;
         html += `</div>`;
         i++;
     }

src/popup/views/confirmTx.js

@@ -139,12 +139,17 @@ function show(txInfo) {
 
     // Balance (with inline USD)
     if (isErc20) {
-        const bal = txInfo.tokenBalance || "0";
-        const balUsd = tokenPrice ? parseFloat(bal) * tokenPrice : null;
-        $("confirm-balance").textContent = valueWithUsd(
-            bal + " " + symbol,
-            balUsd,
-        );
+        // null is a balance whose scale nothing knows, not a balance of zero
+        // (https://git.eeqj.de/sneak/AutistMask/issues/349). The send is
+        // refused at encode time for the same missing scale; what this line
+        // must not do is state a quantity nobody established.
+        const bal = txInfo.tokenBalance;
+        const balUsd =
+            tokenPrice && bal != null ? parseFloat(bal) * tokenPrice : null;
+        $("confirm-balance").textContent =
+            bal == null
+                ? "unknown (" + symbol + ")"
+                : valueWithUsd(bal + " " + symbol, balUsd);
     } else {
         const bal = txInfo.balance || "0";
         const balUsd = ethPrice ? parseFloat(bal) * ethPrice : null;
@@ -235,17 +240,22 @@ function renderValidation(txInfo) {
     }
     if (codes.includes(CODES.INSUFFICIENT_TOKEN)) {
         messages.push(
-            "Insufficient " +
-                symbol +
-                " balance. You have " +
-                txInfo.tokenBalance +
-                " " +
-                symbol +
-                " but are trying to send " +
-                txInfo.amount +
-                " " +
-                symbol +
-                ".",
+            txInfo.tokenBalance == null
+                ? "This token's balance is unknown, because nothing this" +
+                      " wallet can consult reports how many decimal places it" +
+                      " uses, so the amount you are trying to send cannot be" +
+                      " checked against it."
+                : "Insufficient " +
+                      symbol +
+                      " balance. You have " +
+                      txInfo.tokenBalance +
+                      " " +
+                      symbol +
+                      " but are trying to send " +
+                      txInfo.amount +
+                      " " +
+                      symbol +
+                      ".",
         );
     }
     if (codes.includes(CODES.INSUFFICIENT_ETH)) {

src/popup/views/helpers.js

@@ -132,6 +132,38 @@ function updateDebugBanner(viewName) {
     }
 }
 
+// The banner shown when a save has failed, registered as the save-failure
+// reporter by src/popup/index.js.
+//
+// Persistent and not dismissable, unlike showFlash(): what it says is true
+// until the popup is closed, and a message that clears itself after two seconds
+// is how the user goes on operating a wallet that is persisting nothing
+// (https://git.eeqj.de/sneak/AutistMask/issues/362). It survives navigation
+// because it hangs off document.body rather than off a view.
+//
+// Created on demand rather than authored in index.html, the same way
+// updateDebugBanner() creates its own: it is absent from a popup where nothing
+// has failed, which is the state that must not need markup to be in.
+//
+// textContent, never innerHTML: `detail` carries an error message, which may
+// come from the browser's storage layer.
+function showSaveFailureBanner(detail) {
+    let banner = document.getElementById("save-failure-banner");
+    if (!banner) {
+        banner = document.createElement("div");
+        banner.id = "save-failure-banner";
+        banner.style.cssText =
+            "background:#c00;color:#fff;text-align:center;font-size:10px;padding:2px 4px;font-family:monospace;position:sticky;top:0;z-index:10000;";
+        document.body.prepend(banner);
+    }
+    const message = (detail && (detail.message || detail.problem)) || detail;
+    banner.textContent =
+        "NOT SAVED — AutistMask could not write to storage, so recent" +
+        " changes are not stored. Close and reopen the popup; if this keeps" +
+        " happening, do not rely on anything you change now." +
+        (message ? " (" + String(message) + ")" : "");
+}
+
 // Callback that renders a view being navigated BACK onto. Set once by
 // index.js via setBackRenderer(), which routes the view through the same
 // per-view render and data guards restoreView() uses.
@@ -197,6 +229,15 @@ function showFlash(msg, duration = 2000) {
     }, duration);
 }
 
+// A stored token balance as a number, or null when there is no number in it.
+// balances.js writes null for a holding whose scale nothing knows, and this
+// keeps that null from becoming a zero one dereference later.
+function unknownableAmount(balance) {
+    if (balance == null) return null;
+    const n = parseFloat(balance);
+    return Number.isFinite(n) ? n : null;
+}
+
 // One row of the balance list: symbol, quantity, fiat value.
 //
 // `symbol` is the ERC-20's own symbol() as the block explorer reported it,
@@ -204,9 +245,18 @@ function showFlash(msg, duration = 2000) {
 // attacker-chosen length until it has been through displaySymbol. This is
 // the row that issue #307 was reported against: every screen that lists a
 // holding renders through here.
+//
+// `amount` is null for a holding whose scale nothing knows
+// (https://git.eeqj.de/sneak/AutistMask/issues/349). There is no quantity to
+// print for it and no fiat value to derive from one, and printing 0.0000 for
+// a real holding is the failure this whole rule exists to prevent, so the row
+// says so instead.
 function balanceLine(symbol, amount, price, tokenId) {
-    const qty = amount.toFixed(4);
-    const usd = price ? formatUsd(amount * price) || " " : " ";
+    const qty = amount === null ? "quantity unknown" : amount.toFixed(4);
+    const usd =
+        price && amount !== null
+            ? formatUsd(amount * price) || " "
+            : " ";
     // tokenId is a contract address out of the same explorer JSON, and it
     // lands inside a quoted attribute.
     const tokenAttr = tokenId ? ` data-token="${escapeHtml(tokenId)}"` : "";
@@ -233,7 +283,12 @@ function balanceLinesForAddress(addr, trackedTokens, showZero) {
     );
     const seen = new Set();
     for (const t of addr.tokenBalances || []) {
-        const bal = parseFloat(t.balance || "0");
+        // A null balance is a holding of an unstatable amount, not a holding
+        // of zero, so the show-zero setting has no say over it: hiding it
+        // would be asserting the zero nobody established. Anything that does
+        // not parse to a finite number is unknown for the same reason — the
+        // `|| "0"` this replaced turned both into a confident zero.
+        const bal = unknownableAmount(t.balance);
         if (bal === 0 && !showZero) continue;
         html += balanceLine(
             t.symbol,
@@ -266,11 +321,22 @@ function addressHoldsFunds(addr) {
     if (!addr) return false;
     if (parseFloat(addr.balance || "0") > 0) return true;
     for (const t of addr.tokenBalances || []) {
-        if (parseFloat(t.balance || "0") > 0) return true;
+        // A null balance is a holding whose amount could not be stated —
+        // balances.js drops a row of zero base units before the scale is
+        // consulted, so a row that survived with no quantity is holding
+        // something. Warning about funds must err towards warning.
+        const bal = unknownableAmount(t.balance);
+        if (bal === null || bal > 0) return true;
     }
     return false;
 }
 
+// The fewest characters of an address any caller may ask to display. The
+// 10-character cap inside truncateMiddle() is the other half of the same
+// guarantee; this is the half that used to be spelled out at each call
+// site, and is now enforced once in renderAddressHtml().
+const ADDRESS_MIN_DISPLAY_LEN = 32;
+
 // Truncate the middle of a string, replacing removed characters with "…".
 // Safety: refuses to truncate more than 10 characters, which is the maximum
 // that still prevents address spoofing attacks (see Display Consistency in
@@ -458,17 +524,29 @@ function attachCopyHandlers(container) {
 
 // Unified address rendering.
 //
-// Produces consistent HTML for any Ethereum address:
-//   • Color dot
-//   • Optional title (e.g. "Wallet 1 — Address 2") shown bold above address
-//   • Optional ENS name shown bold above address
-//   • Full address (or truncated via maxLen) with dashed-underline click-to-copy
-//   • Etherscan external link icon
+// Two stacked rows, in this order:
+//   1. Identity strip — colour dot, optional title (e.g. "Wallet 1 —
+//      Address 2") and the explorer link icon. Optional ENS name below it.
+//   2. The address itself, alone on a full-width row that never wraps
+//      (see .am-address in styles/main.css).
+//
+// The split is the point. Everything used to sit on one line: dot, address
+// and link together, with `break-all` to let the address fold when the line
+// ran out. In the wallet list, where the row also carried [info] and [x],
+// it ran out every time — the bug in #380 — and a folded address is a
+// spoofing hazard, not a cosmetic one. Nothing shares the address's row
+// now, so all 42 characters fit at every nesting depth the popup uses and
+// nothing has to be dropped or folded to make room.
 //
 // Options object:
 //   title    — wallet title string (from addressTitle)
 //   ensName  — ENS name string
-//   maxLen   — if set, truncate address display (min 32 chars enforced)
+//   maxLen   — if set, truncate address display. Floored at 32 characters
+//              here rather than by the caller: no view passes it any more
+//              (every address row is wide enough for all 42 characters),
+//              so a floor that lived in the callers would have gone away
+//              with them, and the "at least 32 characters" guarantee has
+//              to survive having no current callers to be a guarantee.
 //   noLink   — if true, omit etherscan link
 //
 // After inserting the returned HTML into the DOM, call
@@ -476,22 +554,22 @@ function attachCopyHandlers(container) {
 function renderAddressHtml(address, opts) {
     const { title, ensName, maxLen, noLink } = opts || {};
     const dot = addressDotHtml(address);
-    const displayAddr = maxLen ? truncateMiddle(address, maxLen) : address;
+    const displayAddr = maxLen
+        ? truncateMiddle(address, Math.max(ADDRESS_MIN_DISPLAY_LEN, maxLen))
+        : address;
     const link = etherscanAddressUrl(address);
     const extLink = noLink ? "" : etherscanLinkHtml(link);
 
     let html = "";
+    html += `<div class="flex items-center">${dot}`;
     if (title) {
-        html += `<div class="flex items-center font-bold">${dot}${escapeHtml(title)}</div>`;
+        html += `<span class="font-bold">${escapeHtml(title)}</span>`;
     }
+    html += `${extLink}</div>`;
     if (ensName) {
-        html += `<div class="flex items-center font-bold">${title ? "" : dot}${escapeHtml(ensName)}</div>`;
-    }
-    if (title || ensName) {
-        html += `<div class="flex items-center">${copyableHtml(displayAddr, "break-all")}${extLink}</div>`;
-    } else {
-        html += `<div class="flex items-center">${dot}${copyableHtml(displayAddr, "break-all")}${extLink}</div>`;
+        html += `<div class="font-bold">${escapeHtml(ensName)}</div>`;
     }
+    html += `<div class="am-address">${copyableHtml(displayAddr)}</div>`;
     return html;
 }
 
@@ -516,6 +594,7 @@ module.exports = {
     showView,
     onViewLeave,
     updateDebugBanner,
+    showSaveFailureBanner,
     setBackRenderer,
     pushCurrentView,
     goBack,
@@ -525,6 +604,7 @@ module.exports = {
     balanceLine,
     balanceLinesForAddress,
     addressHoldsFunds,
+    unknownableAmount,
     addressColor,
     addressDotHtml,
     escapeHtml,

src/popup/views/home.js

@@ -9,7 +9,6 @@ const {
     addressTitle,
     escapeHtml,
     displaySymbol,
-    truncateMiddle,
     renderAddressHtml,
     attachCopyHandlers,
     pushCurrentView,
@@ -117,10 +116,13 @@ function renderHomeTxList(ctx) {
         const amountStr = tx.value
             ? escapeHtml(tx.value + " " + sym)
             : escapeHtml(sym);
+        // The counterparty used to be squeezed in beside the amount and
+        // truncated to whatever was left over. It gets its own row now and
+        // is shown whole; the title, when it is one of our own addresses,
+        // names it on the line above rather than replacing it.
         const title = addressTitle(counterparty, state.wallets);
-        const maxAddr = Math.max(32, 36 - Math.max(0, amountStr.length - 10));
-        const displayAddr = title || truncateMiddle(counterparty, maxAddr);
-        const addrStr = escapeHtml(displayAddr);
+        const titleStr = title ? escapeHtml(title) : "";
+        const addrStr = escapeHtml(counterparty);
         const dot = addressDotHtml(counterparty);
         const err = tx.isError ? " (failed)" : "";
         const opacity = tx.isError ? " opacity:0.5;" : "";
@@ -128,7 +130,8 @@ function renderHomeTxList(ctx) {
         const iso = escapeHtml(isoDate(tx.timestamp));
         html += `<div class="home-tx-row py-2 border-b border-border-light text-xs cursor-pointer hover:bg-hover" data-tx="${i}" style="${opacity}">`;
         html += `<div class="flex justify-between"><span class="text-muted" title="${iso}">${ago}</span><span>${dirLabel}${err}</span></div>`;
-        html += `<div class="flex justify-between"><span class="flex items-center">${dot}${addrStr}</span><span>${amountStr}</span></div>`;
+        html += `<div class="flex justify-between"><span class="flex items-center">${dot}${titleStr}</span><span>${amountStr}</span></div>`;
+        html += `<div class="am-address">${addrStr}</div>`;
         html += `</div>`;
         i++;
     }
@@ -252,17 +255,22 @@ function walletListHtml() {
                 : "";
             const dot = addressDotHtml(addr.address);
             const titleBold = isActive ? "font-bold" : "";
-            html += `<div class="text-xs ${titleBold}">Address ${ai + 1}</div>`;
+            // [info] and [x] ride on the "Address N" line, which was empty
+            // to its right, so the address below gets the row to itself.
+            // They used to sit beside the address and take about a third of
+            // the width off it, which is what made a 42-character address
+            // fold onto a second line here and nowhere else (#380).
+            html += `<div class="flex text-xs items-center justify-between">`;
+            html += `<span class="flex items-center ${titleBold}">${dot}Address ${ai + 1}</span>`;
+            html += `<span class="flex-shrink-0 ml-1">${infoBtn}${removeBtn}</span>`;
+            html += `</div>`;
             if (addr.ensName) {
                 // An ENS reverse record is whatever the name owner set it
                 // to; renderAddressHtml() escapes its own copy of this and
                 // this list was the one that did not.
-                html += `<div class="text-xs font-bold flex items-center">${dot}${escapeHtml(addr.ensName)}</div>`;
+                html += `<div class="text-xs font-bold">${escapeHtml(addr.ensName)}</div>`;
             }
-            html += `<div class="flex text-xs items-center justify-between">`;
-            html += `<span class="flex items-center break-all">${addr.ensName ? "" : dot}${escapeHtml(addr.address)}</span>`;
-            html += `<span class="flex-shrink-0 ml-1">${infoBtn}${removeBtn}</span>`;
-            html += `</div>`;
+            html += `<div class="am-address text-xs">${escapeHtml(addr.address)}</div>`;
             const addrTotal = formatAddressTotal(getAddressValue(addr));
             html += `<div class="text-xs text-muted text-right min-h-[1rem]">${addrTotal || "&nbsp;"}</div>`;
             html += balanceLinesForAddress(

src/popup/views/send.js

@@ -12,6 +12,7 @@ const {
 const { state, currentAddress } = require("../../shared/state");
 let ctx;
 const { getProvider } = require("../../shared/balances");
+const { resolveTokenDecimals } = require("../../shared/approvalAmount");
 const { resolveSymbol } = require("../../shared/tokenList");
 const { isLowHolderCount } = require("../../shared/holders");
 const { isSpoofedSymbol } = require("../../shared/symbolSpoof");
@@ -159,9 +160,14 @@ function updateSendBalance() {
             addr.tokenBalances,
             state.trackedTokens,
         );
-        const bal = tb ? tb.balance || "0" : "0";
+        // A null balance is a holding whose scale nothing knows. Saying "0"
+        // for it would be a claim about the amount; the send itself is
+        // refused later by transferAmountUnits() for the same missing scale.
+        const bal = tb ? tb.balance : "0";
         $("send-balance").textContent =
-            "Current balance: " + bal + " " + symbol;
+            bal == null
+                ? "Current balance: unknown (" + symbol + ")"
+                : "Current balance: " + bal + " " + symbol;
     }
 }
 
@@ -235,8 +241,45 @@ function init(_ctx) {
                 addr.tokenBalances,
                 state.trackedTokens,
             );
-            tokenBalance = tb ? tb.balance || "0" : "0";
-            tokenDecimals = tb ? tb.decimals : null;
+            // null carried through rather than flattened to "0": the confirm
+            // screen states an unknown balance as unknown, and
+            // validateTransfer() treats it as no balance to spend from, which
+            // is the fail-closed side of an amount nobody can check.
+            tokenBalance = tb ? (tb.balance ?? null) : "0";
+            // Resolved the same way balances.js resolved the scale it
+            // DISPLAYED this token's balance at: bundled list, then the user's
+            // tracked tokens, then the explorer. The stored
+            // tokenBalances[].decimals is the explorer's own answer alone, so
+            // reading it raw carries a null forward for a token the wallet
+            // does know the scale of — and displayedDecimals() then throws
+            // inside estimateGas(), which the confirmation screen reports as
+            // an unestimable fee. Unsendable, over a scale that was never in
+            // doubt (https://git.eeqj.de/sneak/AutistMask/issues/349).
+            // Still null when nothing knows: no fallback.
+            //
+            // Resolved WITH `wallets`, which balances.js does not pass: that
+            // adds explorerDecimals()'s cross-address check, so a contract two
+            // addresses report different scales for answers null rather than
+            // picking one. That check has to apply here, because this value
+            // encodes a transfer; balances.js is formatting one explorer row
+            // at fetch time and cannot consult a state it is in the middle of
+            // replacing.
+            tokenDecimals = resolveTokenDecimals(token, {
+                trackedTokens: state.trackedTokens,
+                wallets: state.wallets,
+            });
+            // The two resolutions can therefore differ, and where they do, the
+            // stored `balance` is a quantity computed at a scale this screen
+            // has just declined to stand behind. Stating it would leave
+            // validateTransfer() checking the amount against a number the
+            // wallet does not vouch for, and — since the unknown-balance path
+            // is gated on the balance, not on the scale — would leave the
+            // fee-estimate failure as the only thing on the confirmation
+            // screen, which says nothing about decimals. Unknown scale means
+            // unknown balance. 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.
+            if (tb && tokenDecimals === null) tokenBalance = null;
         }
 
         ctx.showConfirmTx({

src/popup/views/transactionDetail.js

@@ -137,10 +137,16 @@ function render() {
         if (tx.contractAddress) {
             const dot = addressDotHtml(tx.contractAddress);
             const link = explorerUrl("token", tx.contractAddress);
+            // Hand-rolled rather than renderAddressHtml() because the
+            // link goes to the explorer's /token/ page, not /address/.
+            // Same two-row shape though: dot and link on the strip, the
+            // contract address alone on the row below it.
             tokenContractEl.innerHTML =
                 `<div class="flex items-center">${dot}` +
-                copyableHtml(tx.contractAddress, "break-all") +
                 etherscanLinkHtml(link) +
+                `</div>` +
+                `<div class="am-address">` +
+                copyableHtml(tx.contractAddress) +
                 `</div>`;
             tokenContractSection.classList.remove("hidden");
         } else {

src/shared/approvalAmount.js

@@ -23,33 +23,14 @@
 // disputed is refused rather than guessed at.
 
 // Solidity's decimals() is a uint8, and every source here is ultimately
-// reporting that call's result.
-const { MAX_DECIMALS } = require("./transferAmount");
+// reporting that call's result. toDecimals() is that check, shared with the
+// send path rather than copied: the bundled list stores numbers, the
+// explorer's copy arrives as a 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");
 
-// A decimals value as a number, or null if it is not one. The bundled list
-// stores numbers, the explorer's copy arrives as a string, and a token the
-// user added by hand can carry whatever lookupTokenInfo() got back, so the
-// accepted types are enumerated rather than coerced: Number([]) is 0 and
-// Number(true) is 1, so a coercing check would read an empty array as a scale
-// of zero and format the amount as whole tokens.
-function toDecimals(value) {
-    let n;
-    if (typeof value === "number") {
-        n = value;
-    } else if (typeof value === "bigint") {
-        if (value < 0n || value > BigInt(MAX_DECIMALS)) return null;
-        n = Number(value);
-    } else if (typeof value === "string") {
-        if (!/^[0-9]+$/.test(value)) return null;
-        n = Number(value);
-    } else {
-        return null;
-    }
-    if (!Number.isInteger(n) || n < 0 || n > MAX_DECIMALS) return null;
-    return n;
-}
-
 // Every decimals the explorer reported for this contract, across all the
 // addresses whose balances have been fetched. They describe one contract, so
 // they should agree; a set that does not agree is a scale in dispute, and this

src/shared/balances.js

@@ -15,6 +15,8 @@ const { deriveAddressFromXpub } = require("./wallet");
 const { TOKEN_BY_ADDRESS } = require("./tokenList");
 const { LOW_HOLDER_THRESHOLD, parseHoldersCount } = require("./holders");
 const { isSpoofedSymbol } = require("./symbolSpoof");
+const { toDecimals } = require("./transferAmount");
+const { resolveTokenDecimals } = require("./approvalAmount");
 
 // Use a static network to skip auto-detection (which can fail and cause
 // "could not coalesce error" on some RPC endpoints like Cloudflare).
@@ -66,10 +68,28 @@ function formatTokenBalance(raw, decimals) {
     return parts[0] + "." + dec;
 }
 
+// The explorer's reported holding as an exact base-unit integer, or null when
+// it reported nothing usable. Base units carry no scale, so this value is
+// meaningful before the scale is known — which is what lets a holding of zero
+// be recognised as zero without guessing a scale to divide it by.
+function rawUnits(value) {
+    if (typeof value === "bigint") return value >= 0n ? value : null;
+    if (typeof value === "number") {
+        return Number.isSafeInteger(value) && value >= 0 ? BigInt(value) : null;
+    }
+    if (typeof value !== "string" || !/^[0-9]+$/.test(value)) return null;
+    return BigInt(value);
+}
+
 // Fetch token balances for a single address from Blockscout.
-// Returns [{ address, symbol, decimals, balance }].
+// Returns [{ address, name, symbol, decimals, balance, holders }].
 // Filters out spam: only shows tokens that are in the known token list,
 // explicitly tracked by the user, or have >= 1000 holders.
+//
+// `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
+// at this point is indistinguishable from a real one everywhere below it.
 async function fetchTokenBalances(address, blockscoutUrl, trackedTokens) {
     try {
         const resp = await debugFetch(
@@ -94,11 +114,46 @@ async function fetchTokenBalances(address, blockscoutUrl, trackedTokens) {
             // is unchanged.
             const type = String(item.token?.type || "").toUpperCase();
             if (type !== "ERC-20") continue;
-            const decimals = parseInt(item.token.decimals || "18", 10);
-            const bal = formatTokenBalance(item.value || "0", decimals);
-            if (bal === "0.0") continue;
 
             const tokenAddr = (item.token.address_hash || "").toLowerCase();
+
+            // What the explorer reported, or null. NEVER a default: this
+            // value is written to state and every later reader — the approval
+            // screen's amount line, the swap lines, the Send screen — takes it
+            // as the token's resolved scale. A fabricated 18 reads exactly
+            // like a real 18 at that point, so it does not merely display the
+            // wrong quantity, it walks straight past the refusal those screens
+            // already have for a scale nobody knows
+            // (https://git.eeqj.de/sneak/AutistMask/issues/349).
+            const decimals = toDecimals(item.token.decimals);
+
+            const raw = rawUnits(item.value);
+            // No usable amount at all is nothing to list, exactly as a
+            // formatted "0.0" was before. Checked on the base-unit integer so
+            // it does not depend on knowing the scale: zero base units is zero
+            // tokens at every scale, and a value the explorer did not report
+            // as an integer is not a holding.
+            if (raw === null || raw === 0n) continue;
+
+            // The scale this row's balance is DISPLAYED at, which is not the
+            // same question as what the explorer said. The bundled list and
+            // the tokens the user tracks both outrank the explorer already
+            // (resolveTokenDecimals), so a token they know keeps showing its
+            // real quantity even when the explorer's entry omits decimals.
+            // Only what neither of them nor the explorer knows is unknown.
+            // The stored `decimals` above stays the explorer's own answer
+            // 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 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.
+            // With a scale, the display filter proper applies: a balance that
+            // rounds to zero at six places is dust and is not listed. Without
+            // one there is no such judgement to make, and the row is kept.
+            const bal = scale === null ? null : formatTokenBalance(raw, scale);
+            if (bal === "0.0") continue;
             // null means the explorer reported no count, which is not the
             // same as a count of zero.  This gate is not the low-holder
             // display filter: it has no user-facing off switch and governs
@@ -127,7 +182,15 @@ async function fetchTokenBalances(address, blockscoutUrl, trackedTokens) {
                 address: item.token.address_hash,
                 name: item.token.name || "",
                 symbol: item.token.symbol || "???",
+                // null means the explorer reported no usable scale — unknown,
+                // not 18. Distinguishable from a real 18 at read time is the
+                // entire point: resolveTokenDecimals() falls through a null to
+                // its refusal, and takes an 18 as the answer.
                 decimals: decimals,
+                // null means nothing anywhere knows the scale, so there is no
+                // token quantity to state. Not "0.0": a nonzero holding shown
+                // as zero is the same lie in the balance list that the
+                // approval screens refuse to tell.
                 balance: bal,
                 holders: holders,
             });

src/shared/persistedState.js

@@ -85,6 +85,14 @@ function isRecord(value) {
 // alternative — refusing the whole record — sends a user whose wallets are
 // perfectly readable to an export-or-erase screen over a token list. An entry
 // that is a record with a text address is kept verbatim, extra fields and all.
+//
+// Verbatim is load-bearing for the fields BESIDE the address. A tokenBalances
+// entry carries `decimals: null` and `balance: null` when nothing knows the
+// token's scale (src/shared/balances.js,
+// https://git.eeqj.de/sneak/AutistMask/issues/349), and those nulls are the
+// record that the value is unknown. Only `address` decides whether an entry
+// survives, so an unknown-scale holding is kept — flooring a null here to some
+// default would put the guess back one layer down from where it was removed.
 function tokenRefs(value) {
     if (!Array.isArray(value)) return [];
     return value.filter(
@@ -92,6 +100,107 @@ function tokenRefs(value) {
     );
 }
 
+// A list of strings, for the fields whose entries are dereferenced as text:
+// fraudContracts (`a.toLowerCase()` in src/popup/views/send.js and
+// src/shared/transactions.js) and each address's hostname list in the site maps
+// below (`h !== host` filters, `list.includes(hostname)` in the background).
+//
+// Same rule as tokenRefs(), for the same reason: the container AND the entries,
+// with a malformed entry DROPPED rather than repaired. A number in a hostname
+// list names no site and a number in fraudContracts names no contract, so there
+// is nothing to repair either to, and the empty list is a legitimate value that
+// survives. The result is a fresh array of primitives, so it shares no
+// structure with `saved`.
+function textList(value) {
+    if (!Array.isArray(value)) return [];
+    return value.filter((entry) => typeof entry === "string");
+}
+
+// allowedSites / deniedSites: { [address]: [hostname, ...] }.
+//
+// The container check these had (truthy and not an array) is not the floor:
+// `{"0xabc…": "notalist"}` IS a non-array object, and the dereference is one
+// level below it. saveState() merges these maps per key and then per hostname
+// WITHIN each key, so a stored value that is not a list reaches `base.map()` in
+// mergeListByIdentity() (src/shared/state.js) and throws — after the popup has
+// rendered, which is why every save from then on failed while the UI looked
+// healthy (https://git.eeqj.de/sneak/AutistMask/issues/362). The Settings
+// revoke button (`list.filter()`), and the background's
+// `allowed.includes(hostname)` gate, dereference it the same way; on that last
+// one a stored string would also answer a SUBSTRING match, so a corrupt map
+// could widen a site permission rather than merely throw.
+//
+// An address key whose value is not a list of hostnames is dropped entirely: it
+// grants and denies nothing, and dropping it fails closed. A stored own
+// "__proto__" key — which JSON can carry — is dropped for the same reason: it
+// can never be a wallet address, so it grants nothing either, and keeping it
+// only keeps a value that saveState()'s merge would hand to the prototype
+// setter on the next write. Keys are written with defineProperty so that no key
+// reaching this function can consult a setter at all, whatever the rule above
+// it becomes; mergeMapByKey() in src/shared/state.js writes the same way.
+function siteMap(value) {
+    const out = {};
+    if (!isRecord(value)) return out;
+    for (const address of Object.keys(value)) {
+        if (address === "__proto__") continue;
+        const hostnames = textList(value[address]);
+        if (hostnames.length === 0) continue;
+        defineOwn(out, address, hostnames);
+    }
+    return out;
+}
+
+// An endpoint URL: non-empty text, or the fallback.
+function url(value, fallback) {
+    return typeof value === "string" && value !== "" ? value : fallback;
+}
+
+// One remembered endpoint pair out of networkEndpoints, floored on the two
+// fields applyChainSwitchFields() (src/shared/chainSwitchFields.js) assigns
+// STRAIGHT ONTO s.rpcUrl / s.blockscoutUrl on the next chain switch: flooring
+// the live fields alone would leave a non-string sitting one switch away from
+// them. A field that is not text is deleted rather than replaced, so the
+// switch falls through its own `|| net.defaultRpcUrl`. Anything else the pair
+// carries is kept: a profile that has been on a build storing more per-network
+// fields must not lose them by passing through this one.
+function endpointPair(value) {
+    const pair = { ...(isRecord(value) ? value : {}) };
+    for (const field of ["rpcUrl", "blockscoutUrl"]) {
+        if (typeof pair[field] !== "string" || pair[field] === "") {
+            delete pair[field];
+        }
+    }
+    return pair;
+}
+
+// A list index into wallets / a wallet's addresses: a non-negative integer, or
+// null for "nothing selected".
+//
+// hasValidAddress() (src/popup/viewRouter.js) guards the restore path with
+// `state.wallets[state.selectedWallet] && …addresses[state.selectedAddress]`,
+// which is safe for a stale INTEGER — out of range is undefined, and the `&&`
+// short-circuits — and NOT safe for a string naming an Array.prototype member.
+// `wallets["map"]` is truthy, so the guard does not short-circuit and
+// `.addresses[…]` throws out of restoreView(): the dead popup. "length",
+// "constructor" and "__proto__" answer the same way, and
+// src/popup/views/confirmTx.js dereferences selectedWallet behind no guard at
+// all.
+function listIndex(value) {
+    return Number.isInteger(value) && value >= 0 ? value : null;
+}
+
+// Write `key` as an own data property, never through a setter. Plain
+// assignment of "__proto__" replaces the object's prototype and records no
+// entry; every map built from stored keys goes through this.
+function defineOwn(obj, key, value) {
+    Object.defineProperty(obj, key, {
+        value: value,
+        writable: true,
+        enumerable: true,
+        configurable: true,
+    });
+}
+
 // Keep only the leading run of stored views the popup is willing to render.
 //
 // restoreView() refuses to reopen ONTO a non-restorable view, but the stack
@@ -187,8 +296,15 @@ function normalizePersisted(saved) {
     out.networkId = isKnownNetworkId(saved.networkId)
         ? saved.networkId
         : DEFAULT_STATE.networkId;
-    out.rpcUrl = saved.rpcUrl || DEFAULT_STATE.rpcUrl;
-    out.blockscoutUrl = saved.blockscoutUrl || DEFAULT_STATE.blockscoutUrl;
+    // Non-empty text or the default, never anything else. getProvider()
+    // (src/shared/balances.js) hands rpcUrl straight to `new
+    // JsonRpcProvider()`, which throws SYNCHRONOUSLY for a value that is not a
+    // string — out of src/popup/views/txStatus.js and src/popup/views/
+    // addWallet.js, neither of which is inside a try, and the first of which a
+    // stored `currentView: "wait-tx"` reaches through restoreView(). It is a
+    // scalar, so the type check is the whole fix.
+    out.rpcUrl = url(saved.rpcUrl, DEFAULT_STATE.rpcUrl);
+    out.blockscoutUrl = url(saved.blockscoutUrl, DEFAULT_STATE.blockscoutUrl);
     // An actual object is required, not merely a truthy non-array: the code
     // below and applyChainSwitchFields() index and ASSIGN INTO this value, and
     // assigning a property to a string or a number is a silent no-op in
@@ -202,19 +318,16 @@ function normalizePersisted(saved) {
             : {};
     out.networkEndpoints = {};
     for (const netId of Object.keys(rawEndpoints)) {
-        // defineProperty, not assignment: a stored map with an own
-        // "__proto__" key — which JSON can carry and assignment treats as the
-        // prototype setter — would otherwise replace this object's prototype
-        // and record no entry at all. Keys other than the known network ids
-        // are kept rather than dropped, so a profile that has been on a build
-        // with more networks does not lose their endpoints by passing through
-        // this one.
-        Object.defineProperty(out.networkEndpoints, netId, {
-            value: { ...rawEndpoints[netId] },
-            writable: true,
-            enumerable: true,
-            configurable: true,
-        });
+        // Keys other than the known network ids are kept rather than dropped,
+        // so a profile that has been on a build with more networks does not
+        // lose their endpoints by passing through this one. That is why an own
+        // "__proto__" key survives here where siteMap() drops it, and why the
+        // write has to go through defineOwn().
+        defineOwn(
+            out.networkEndpoints,
+            netId,
+            endpointPair(rawEndpoints[netId]),
+        );
     }
     // A profile written before this map existed carries exactly one pair of
     // endpoints, belonging to whatever network it was last on. Adopt it as
@@ -239,14 +352,8 @@ function normalizePersisted(saved) {
         typeof saved.activeAddress === "string" && saved.activeAddress !== ""
             ? saved.activeAddress
             : null;
-    out.allowedSites =
-        saved.allowedSites && !Array.isArray(saved.allowedSites)
-            ? structuredClone(saved.allowedSites)
-            : {};
-    out.deniedSites =
-        saved.deniedSites && !Array.isArray(saved.deniedSites)
-            ? structuredClone(saved.deniedSites)
-            : {};
+    out.allowedSites = siteMap(saved.allowedSites);
+    out.deniedSites = siteMap(saved.deniedSites);
     out.rememberSiteChoice =
         saved.rememberSiteChoice !== undefined
             ? saved.rememberSiteChoice
@@ -279,16 +386,32 @@ function normalizePersisted(saved) {
             : 100000;
     out.utcTimestamps =
         saved.utcTimestamps !== undefined ? saved.utcTimestamps : false;
-    out.fraudContracts = structuredClone(saved.fraudContracts || []);
+    // A list of contract addresses, floored the same way: send.js builds its
+    // fraud set as `(state.fraudContracts || []).map((a) => a.toLowerCase())`
+    // and filterTransactions() maps the same list through normalizeAddress(),
+    // so a stored string walks through the `|| []` and a stored number walks
+    // through an Array.isArray().
+    out.fraudContracts = textList(saved.fraudContracts);
     out.tokenHolderCache = structuredClone(saved.tokenHolderCache || {});
     out.theme = saved.theme || "system";
     out.debugMode = saved.debugMode !== undefined ? saved.debugMode : false;
     out.currentView = saved.currentView || null;
-    out.selectedWallet =
-        saved.selectedWallet !== undefined ? saved.selectedWallet : null;
-    out.selectedAddress =
-        saved.selectedAddress !== undefined ? saved.selectedAddress : null;
-    out.selectedToken = saved.selectedToken || null;
+    out.selectedWallet = listIndex(saved.selectedWallet);
+    out.selectedAddress = listIndex(saved.selectedAddress);
+    // "ETH", or a contract address, or null — never anything else. The popup
+    // restores onto "address-token" behind a truthiness check on this field and
+    // then dereferences it as text (`tokenId.toLowerCase()` in
+    // src/popup/views/addressToken.js, `state.selectedToken.toLowerCase()` in
+    // src/popup/views/receive.js), so a stored number is truthy, passes the
+    // restore gate, and throws on the screen it restores onto. Found by the
+    // sweep for this same defect class in
+    // https://git.eeqj.de/sneak/AutistMask/issues/362; floored to null, which
+    // is what the restore gate already treats as "nothing selected". The empty
+    // string was already falsy here and stays null.
+    out.selectedToken =
+        typeof saved.selectedToken === "string" && saved.selectedToken !== ""
+            ? saved.selectedToken
+            : null;
     out.viewData = structuredClone(saved.viewData || {});
     out.viewStack = restorableStack(saved.viewStack, out.currentView);
     return out;

src/shared/prices.js

@@ -78,9 +78,18 @@ function getAddressValue(addr) {
     let usd = parseFloat(addr.balance || "0") * prices.ETH;
     let partial = false;
     for (const token of addr.tokenBalances || []) {
-        const tokenBal = parseFloat(token.balance || "0");
+        // A null balance is a holding whose scale nothing knows, so it has no
+        // quantity to price — but it is still a holding, and a total that
+        // silently omits it would read as complete. That is exactly what
+        // `partial` is for (https://git.eeqj.de/sneak/AutistMask/issues/349).
+        if (token.balance == null) {
+            partial = true;
+            continue;
+        }
+        const tokenBal = parseFloat(token.balance);
         // A balance of zero is not a holding: it can neither add to the total
-        // nor make it incomplete.
+        // nor make it incomplete. Anything that is not a number at all is not
+        // a holding this can price either, and is left to the same rule.
         if (!(tokenBal > 0)) continue;
         if (prices[token.symbol]) {
             usd += tokenBal * prices[token.symbol];

src/shared/state.js

@@ -310,12 +310,26 @@ function mergeAddress(base, ours, theirs) {
 // a key another page edited. Unlike an array's identity function, an object
 // key can't collide with a different logical entry (Object.keys() is
 // already deduplicated), so this needs no collision floor of its own.
+//
+// Every write goes through defineProperty rather than assignment. The keys are
+// whatever the stored record carries, and plain assignment of "__proto__" —
+// which JSON can carry and normalizePersisted() keeps for networkEndpoints —
+// replaces this object's prototype and records no entry. That would undo one
+// layer downstream exactly what defineOwn() does in
+// src/shared/persistedState.js.
 function mergeMapByKey(base, ours, theirs, mergeLeaf) {
     base = base || {};
     ours = ours || {};
     theirs = theirs || {};
     const result = {};
     const seen = new Set();
+    const put = (key, value) =>
+        Object.defineProperty(result, key, {
+            value: value,
+            writable: true,
+            enumerable: true,
+            configurable: true,
+        });
 
     for (const key of Object.keys(theirs)) {
         seen.add(key);
@@ -323,16 +337,16 @@ function mergeMapByKey(base, ours, theirs, mergeLeaf) {
         const inOurs = Object.prototype.hasOwnProperty.call(ours, key);
         if (inBase && !inOurs) continue; // this page deleted the whole entry
         if (inOurs) {
-            result[key] = mergeLeaf(base[key], ours[key], theirs[key]);
+            put(key, mergeLeaf(base[key], ours[key], theirs[key]));
         } else {
-            result[key] = theirs[key];
+            put(key, theirs[key]);
         }
     }
 
     for (const key of Object.keys(ours)) {
         if (seen.has(key)) continue;
         if (!Object.prototype.hasOwnProperty.call(base, key)) {
-            result[key] = ours[key];
+            put(key, ours[key]);
         }
     }
 
@@ -522,11 +536,51 @@ async function saveStateOnce() {
 // begins, so each one only ever sees the true live state at its turn.
 let saveQueue = Promise.resolve();
 
+// Where a failed save is REPORTED, set once by the context that has a screen
+// to say it on (src/popup/index.js).
+//
+// A save that fails must not fail silently. showView() fires saveState() on
+// every navigation without awaiting it, and the queue below has to attach a
+// rejection handler to keep advancing — so a failing save was swallowed
+// entirely: no throw, no message, nothing on screen. The wallet kept running
+// against storage that was rejecting every write, which is the data-loss half
+// of https://git.eeqj.de/sneak/AutistMask/issues/362. The awaited callers were
+// no better off: `await saveState()` inside an unguarded event handler surfaces
+// in the console and nowhere the user looks.
+//
+// This is the "tell the user" half; the other half is the floor in
+// normalizePersisted(), which stops the malformed-record cause from arising in
+// the first place. Both, because a floor only covers the causes it knows about
+// and storage can still fail for reasons of its own (quota, a revoked
+// permission, a record a newer build wrote).
+let saveFailureHandler = null;
+
+function onSaveFailure(fn) {
+    saveFailureHandler = fn;
+}
+
+function reportSaveFailure(err) {
+    log.errorf("state: saving failed, changes were NOT persisted:", err);
+    if (!saveFailureHandler) return;
+    try {
+        saveFailureHandler(err);
+    } catch (e) {
+        // The reporter is the last thing standing between a failed save and
+        // silence; a reporter that throws must not become an unhandled
+        // rejection of its own on top of it.
+        log.errorf("state: the save-failure reporter itself failed:", e);
+    }
+}
+
 function saveState() {
     const turn = saveQueue.then(saveStateOnce);
     // The queue must advance even when a save rejects, or every save after
     // it queues behind a promise that never settles.
     saveQueue = turn.catch(() => {});
+    // Every failed save is reported, whether or not the caller awaited this
+    // one. The returned promise still rejects, so a caller that DOES await
+    // keeps its own error handling.
+    turn.catch(reportSaveFailure);
     return turn;
 }
 
@@ -574,6 +628,7 @@ function currentAddress() {
 module.exports = {
     state,
     saveState,
+    onSaveFailure,
     loadState,
     currentAddress,
     currentNetwork,

src/shared/stateSchema.js

@@ -26,29 +26,42 @@
 //
 // What is checked HERE is what nothing downstream can floor: the wallet list,
 // the version, and the network id that keys an object. Every other field is
-// normalizePersisted()'s to make safe, and what that function does today is
-// NOT uniform. The four kinds of floor it applies, listed so a reader can tell
-// which one a given field has without reading it off:
+// normalizePersisted()'s to make safe, and what that function does is NOT
+// uniform across the record.
 //
-//   Type-checked, container AND entries: trackedTokens, each address's
-//     tokenBalances, networkId, networkEndpoints, activeAddress, viewStack.
-//     These are the fields something dereferences structurally — iterated,
-//     indexed, assigned into, or .toLowerCase()'d — where a truthy value of
-//     the wrong type throws on the first read. The entries matter as much as
-//     the container: [1, 2] IS a list, and `t.address` is one level below the
-//     Array.isArray().
-//   Container shape only: allowedSites, deniedSites. A falsy value or a list
-//     becomes {}; anything else is taken as stored and the entries are not
-//     checked.
-//   `saved.x || default`, no type check: rpcUrl, blockscoutUrl,
-//     lastBalanceRefresh, fraudContracts, tokenHolderCache, theme,
-//     currentView, selectedToken, viewData.
-//   Present-or-default, value taken verbatim: every boolean flag,
-//     dustThresholdGwei, selectedWallet, selectedAddress.
+// WHICH FLOOR A GIVEN FIELD HAS IS NOT WRITTEN HERE. It is
+// tests/persistedFieldContract.test.js: one row per persisted field, naming
+// the property that field's floor is claimed to have, and PROVING it by
+// driving the real code with hostile values — the gate for a field the gate
+// refuses, normalizePersisted() for a field it floors, and, for a field whose
+// only defence is that nothing dereferences it structurally, a boot of the
+// real popup entry point onto EVERY view the popup can reopen onto.
 //
-// A field added to the record needs a check here or a floor there, chosen by
-// what reads it: anything dereferenced structurally needs the type check, and
-// neither of the last two kinds is one.
+// That last part is the whole point, because this defect class lives on the
+// RESTORE path and not on Home. Take the claim NARROWLY, exactly as that file
+// states it: what those boots prove is no structural dereference on the code
+// paths a WHOLLY-CORRUPTED PROFILE takes — which is not every path a stored
+// record takes. Not driven: any pairing of values the four slots do not
+// produce, a view only forward navigation opens, anything behind a click, and
+// everything a healthy profile reaches. Within that boundary the verdict is
+// unconditional, including a dereference that takes two corrupted fields at
+// once. That suite also goes red on a field that gains a floor while its row
+// still claims it has none, and on a field added to PERSISTED_FIELDS with no
+// row at all.
+//
+// That test exists because this comment did not work. It carried a
+// hand-written justification per field, and it shipped a false one in three
+// consecutive changes — a different field each time, each caught only by a
+// reviewer re-deriving thirty fields by hand. A claim nobody can execute is
+// worse than no claim, because it is believed.
+//
+// The trap is worth stating here, since it is what all three got wrong: a
+// check on a CONTAINER is not a check on its ENTRIES, and the dereference is
+// one level below the container. `[1, 2]` is a list, `{"0x…": "notalist"}` is
+// a record, and `{"currentView":"success-tx","viewData":{"hash":"0x1"}}`
+// passes the restore gate and throws on the address the renderer below it
+// reads. A field added to the record needs a decision about its entries as
+// well as its shape — and then a row in that test.
 
 const { isKnownNetworkId } = require("./networks");
 

src/shared/transactions.js

@@ -11,6 +11,10 @@ const { log, debugFetch } = require("./log");
 const { TOKEN_BY_ADDRESS } = require("./tokenList");
 const { parseHoldersCount, isLowHolderCount } = require("./holders");
 const { isSpoofedSymbol } = require("./symbolSpoof");
+// The uint8 test every scale in this wallet goes through. Shared, not copied:
+// a scale is either reported or it is unknown, and "unknown" must mean the
+// same thing here as it does on the screens that refuse to format one.
+const { toDecimals } = require("./transferAmount");
 // The plain 4-decimal rule. The history and balance lists deliberately keep
 // truncation without the approval screens' nonzero floor: the transaction
 // detail view is the authoritative record and already shows exact precision.
@@ -92,21 +96,37 @@ function parseTx(tx, addrLower) {
 function parseTokenTransfer(tt, addrLower) {
     const from = tt.from?.hash || "";
     const to = tt.to?.hash || "";
-    const decimals = parseInt(tt.total?.decimals || "18", 10);
+    // The explorer's own answer, or null. Never a default: a transfer of
+    // 5000000000 units formatted at a guessed 18 reads as 0.000000005, and
+    // nothing downstream can tell that from a real 18-decimal transfer of
+    // that size. `parseInt(x || "18", 10)` also collapsed a genuine scale of
+    // ZERO into 18 (https://git.eeqj.de/sneak/AutistMask/issues/246).
+    const decimals = toDecimals(tt.total?.decimals);
     const rawVal = tt.total?.value || "0";
     const direction =
         normalizeAddress(from) === addrLower ? "sent" : "received";
     const sym = tt.token?.symbol || "?";
+    // Without a scale there is no token quantity, so none is stated: the list
+    // row falls back to the symbol alone and the detail screen to its
+    // direction label, exactly as the contract-call rows above already do.
+    // The exact figure is not lost — it is the base-unit line below, which is
+    // the one number that needs no scale to be true.
+    const formatted =
+        decimals === null ? "" : formatTxValue(formatUnits(rawVal, decimals));
+    const exact = decimals === null ? "" : formatUnits(rawVal, decimals);
     return {
         hash: tt.transaction_hash,
         blockNumber: tt.block_number,
         timestamp: Math.floor(new Date(tt.timestamp).getTime() / 1000),
         from: from,
         to: to,
-        value: formatTxValue(formatUnits(rawVal, decimals)),
-        exactValue: formatUnits(rawVal, decimals),
+        value: formatted,
+        exactValue: exact,
         rawAmount: rawVal,
-        rawUnit: sym + " base units (10^-" + decimals + ")",
+        rawUnit:
+            decimals === null
+                ? sym + " base units (decimals unknown)"
+                : sym + " base units (10^-" + decimals + ")",
         valueGwei: null,
         symbol: sym,
         direction: direction,

src/shared/transferAmount.js

@@ -52,7 +52,7 @@ function mismatchMessage(displayed, onChain) {
     );
 }
 
-// A decimals value from either source as a number, or null if it is not one.
+// A decimals value from any source as a number, or null if it is not one.
 // decimals() comes back from ethers as a bigint and the explorer's copy arrives
 // as a string, so both of those are accepted alongside a plain number; anything
 // fractional, negative, out of uint8 range, or of any other type at all is not.
@@ -60,7 +60,16 @@ function mismatchMessage(displayed, onChain) {
 // The types are enumerated rather than coerced because Number() is far too
 // willing: Number([]) is 0 and Number(true) is 1, so a coercing check would
 // admit an empty array as a scale of zero and encode a whole-token transfer
-// against it.
+// against it. Absence answers null and never a default, and a real scale of
+// ZERO answers 0 — the two are different answers, which is the whole point:
+// a falsy-collapsing `value || 18` cannot tell them apart, and neither can a
+// reader of what it wrote (https://git.eeqj.de/sneak/AutistMask/issues/246).
+//
+// Exported because every module that has to decide whether it knows a token's
+// scale needs exactly this test, and three separate copies of it is three
+// places for the answer to drift: approvalAmount.js resolves the scale the
+// approval screens display at, and balances.js decides what the explorer
+// actually reported before it is stored.
 function toDecimals(value) {
     let n;
     if (typeof value === "number") {
@@ -110,6 +119,7 @@ module.exports = {
     displayedDecimals,
     transferAmountUnits,
     mismatchMessage,
+    toDecimals,
     MAX_DECIMALS,
     UNKNOWN_DISPLAYED_DECIMALS_MESSAGE,
     UNREADABLE_CONTRACT_DECIMALS_MESSAGE,

src/shared/uniswap.js

@@ -48,13 +48,79 @@ function formatAmount(raw, decimals) {
     return truncateAmountNeverZero(formatUnits(raw, decimals));
 }
 
+// One wording for either side of the screen: a currency the calldata never
+// named. It reads as a refusal, the same stance unknownDecimalsAmount() takes
+// on a scale — not as a token name, and not as a quantity.
+const UNNAMED_CURRENCY = "Unknown (not named in the calldata)";
+
+// Explicit presence, never truthiness. Every gate in this file that guards a
+// decoded value goes through here: an address is never falsy once set, but an
+// amount of 0n is, and a gate that cannot tell a genuine zero from an absent
+// value is the trap this decoder has now been bitten by five times.
+function present(value) {
+    return value !== null && value !== undefined;
+}
+
+// Uniswap V4 spells "use the whole open delta" as an amount of zero:
+// v4-periphery `src/libraries/ActionConstants.sol` declares
+// `uint128 internal constant OPEN_DELTA = 0` ("used to signal that an action
+// should use the input value of the open delta on the pool manager or of the
+// balance that the contract holds"), and `src/V4Router.sol` substitutes the
+// full open credit whenever an exact-in swap action's `amountIn` equals it:
+//
+//     uint128 amountIn = params.amountIn;
+//     if (amountIn == ActionConstants.OPEN_DELTA) {
+//         amountIn = _getFullCredit(...).toUint128();
+//     }
+//
+// in both `_swapExactInputSingle` and `_swapExactInput`. Sentinel and literal
+// zero are the same uint128 word, so the encoding CANNOT distinguish them —
+// and the router does not try: it reads every zero as the sentinel, so in V4
+// there is no such thing as an exact-in swap of literally zero. The amount is
+// therefore not stated by the calldata at all; it is whatever credit is open
+// at execution time. It is carried as this sentinel rather than as 0n because
+// printing "0.0000" would state the exact inverse of what will happen —
+// "nothing is being swapped" for a step that swaps the entire balance.
+//
+// `amountOutMinimum` gets no such mapping: V4Router compares it directly
+// (`if (amountOut < params.amountOutMinimum) revert V4TooLittleReceived`), so
+// a zero minimum is a literal zero slippage floor and is stated as one. Nor do
+// the V2/V3 paths have it — universal-router's `V3SwapRouter.v3SwapExactInput`
+// special-cases only `ActionConstants.CONTRACT_BALANCE` (1<<255), never zero —
+// so a zero `amountIn` there is a literal zero and is displayed as one.
+const OPEN_DELTA = Symbol("v4-open-delta");
+
+// The two amount lines that state a fact instead of a quantity. Same register
+// as UNNAMED_CURRENCY — a sentence in the value slot, so it cannot be misread
+// as a number — and deliberately not a third phrasing of "not named": these
+// say different things.
+const OPEN_DELTA_AMOUNT = "All available (V4 open delta)";
+const NO_MINIMUM = "None (no minimum guaranteed)";
+
+// Permit2 amounts are uint160; the maximum is Permit2's "unbounded".
+const MAX_UINT160 = BigInt("0xffffffffffffffffffffffffffffffffffffffff");
+
 // `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.
+//
+// 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
+// V4 spells native ETH as `Currency.wrap(address(0))` (v4-core
+// `type Currency is address`), and a Currency is ABI-encoded as a plain
+// address word, so every decode site here gets back the truthy string
+// "0x0000000000000000000000000000000000000000" for it — never null. WRAP_ETH
+// sets that same explicit zero address, and an UNWRAP_WETH output is caught by
+// its caller before this is consulted, so nothing that genuinely is ETH
+// arrives null. Naming a null ETH states the wrong asset and formats its
+// amount at the wrong scale.
 function tokenInfo(address, sources) {
-    if (!address || address === "0x0000000000000000000000000000000000000000") {
+    if (!address) {
+        return { symbol: null, decimals: null, address: null };
+    }
+    if (address === "0x0000000000000000000000000000000000000000") {
         return { symbol: "ETH", decimals: 18, address: null };
     }
     const t = TOKEN_BY_ADDRESS.get(address.toLowerCase());
@@ -205,6 +271,14 @@ const V4_SWAP_EXACT_OUT = 0x09;
 const V4_SETTLE = 0x0b;
 const V4_TAKE = 0x0e;
 
+// A V4 exact-in `amountIn`, read the way V4Router reads it: zero is
+// ActionConstants.OPEN_DELTA, not a quantity of zero. See the OPEN_DELTA
+// comment above. The exact-OUT actions below decode no amounts at all, so
+// their own OPEN_DELTA mapping on `amountOut` never reaches the screen.
+function v4ExactInAmount(raw) {
+    return raw === 0n ? OPEN_DELTA : raw;
+}
+
 // Decode V4_SWAP (command 0x10) input bytes.
 // The input is ABI-encoded as (bytes actions, bytes[] params).
 // We extract token addresses from SETTLE (input) and TAKE (output) sub-actions,
@@ -253,13 +327,17 @@ function decodeV4Swap(input) {
                                 ],
                                 params[i],
                             );
-                            if (!settleToken) settleToken = s[0][0];
+                            if (!present(settleToken)) settleToken = s[0][0];
                             const path = s[0][1];
-                            if (path.length > 0 && !takeToken) {
+                            if (path.length > 0 && !present(takeToken)) {
                                 takeToken = path[path.length - 1][0];
                             }
-                            if (!amountIn) amountIn = s[0][2];
-                            if (!amountOutMin) amountOutMin = s[0][3];
+                            if (!present(amountIn)) {
+                                amountIn = v4ExactInAmount(s[0][2]);
+                            }
+                            if (!present(amountOutMin)) {
+                                amountOutMin = s[0][3];
+                            }
                         } catch {
                             // Fall through — SETTLE/TAKE will provide tokens
                         }
@@ -275,16 +353,20 @@ function decodeV4Swap(input) {
                             );
                             const poolKey = s[0][0];
                             const zeroForOne = s[0][1];
-                            if (!settleToken)
+                            if (!present(settleToken))
                                 settleToken = zeroForOne
                                     ? poolKey[0]
                                     : poolKey[1];
-                            if (!takeToken)
+                            if (!present(takeToken))
                                 takeToken = zeroForOne
                                     ? poolKey[1]
                                     : poolKey[0];
-                            if (!amountIn) amountIn = s[0][2];
-                            if (!amountOutMin) amountOutMin = s[0][3];
+                            if (!present(amountIn)) {
+                                amountIn = v4ExactInAmount(s[0][2]);
+                            }
+                            if (!present(amountOutMin)) {
+                                amountOutMin = s[0][3];
+                            }
                         } catch {
                             // Fall through
                         }
@@ -301,9 +383,9 @@ function decodeV4Swap(input) {
                                 ],
                                 params[i],
                             );
-                            if (!takeToken) takeToken = s[0][0];
+                            if (!present(takeToken)) takeToken = s[0][0];
                             const path = s[0][1];
-                            if (path.length > 0 && !settleToken) {
+                            if (path.length > 0 && !present(settleToken)) {
                                 settleToken = path[path.length - 1][0];
                             }
                         } catch {
@@ -319,11 +401,11 @@ function decodeV4Swap(input) {
                             );
                             const poolKey = s[0][0];
                             const zeroForOne = s[0][1];
-                            if (!settleToken)
+                            if (!present(settleToken))
                                 settleToken = zeroForOne
                                     ? poolKey[0]
                                     : poolKey[1];
-                            if (!takeToken)
+                            if (!present(takeToken))
                                 takeToken = zeroForOne
                                     ? poolKey[1]
                                     : poolKey[0];
@@ -362,11 +444,44 @@ function decode(data, toAddress, sources) {
 
         let inputToken = null;
         let inputAmount = null;
+        let inputEstablished = false;
         let outputToken = null;
         let minOutput = null;
         let hasUnwrapWeth = false;
         const commandNames = [];
 
+        // THE INVARIANT: an amount and the token it is counted in always come
+        // from the same hop. 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
+        // amount of 0n is, so gating the two halves independently let a hop
+        // with a zero amount fix the token and leave the amount open; the next
+        // hop's figure was then displayed against the first hop's token, at the
+        // first hop's scale. A V3 USDT->WETH hop with amountIn 0 followed by a
+        // V2 WETH->USDC hop of 0.5e18 rendered "500000000000.0000 USDT".
+        //
+        // The input side is fixed by the first hop that states either half, the
+        // output side by the last, because the final leg is what the user
+        // receives. A half the establishing hop did not state stays null and
+        // the line says so, rather than being filled in from a different hop.
+        const setInput = (token, amount) => {
+            inputToken = present(token) ? token : null;
+            inputAmount = present(amount) ? amount : null;
+            inputEstablished = true;
+        };
+        const setInputOnce = (token, amount) => {
+            if (inputEstablished) return;
+            if (!present(token) && !present(amount)) return;
+            setInput(token, amount);
+        };
+        const setOutput = (token, amount) => {
+            if (!present(token) && !present(amount)) return;
+            outputToken = present(token) ? token : null;
+            minOutput = present(amount) ? amount : null;
+        };
+
         for (let i = 0; i < commandsBytes.length; i++) {
             const cmdId = commandsBytes[i] & 0x1f;
             commandNames.push(
@@ -377,69 +492,61 @@ function decode(data, toAddress, sources) {
             try {
                 if (cmdId === 0x0a) {
                     const p = decodePermit2(inputs[i]);
-                    if (p) {
-                        inputToken = p.token;
-                        inputAmount = p.amount;
-                    }
+                    // A permit states both halves itself, so it may replace an
+                    // input side an earlier hop established without breaking
+                    // the invariant.
+                    if (p) setInput(p.token, p.amount);
                 }
 
                 if (cmdId === 0x0e) {
                     const b = decodeBalanceCheck(inputs[i]);
-                    if (b) {
-                        outputToken = b.token;
-                        minOutput = b.minBalance;
-                    }
+                    if (b) setOutput(b.token, b.minBalance);
                 }
 
                 if (cmdId === 0x00) {
                     const s = decodeV3SwapExactIn(inputs[i]);
                     if (s) {
-                        if (!inputToken) inputToken = s.tokenIn;
-                        if (!inputAmount) inputAmount = s.amountIn;
+                        setInputOnce(s.tokenIn, s.amountIn);
                         // Always update output: in multi-step swaps (V3 → V4),
                         // the last swap step determines the final output token
                         // and minimum received amount.
-                        outputToken = s.tokenOut;
-                        minOutput = s.amountOutMin;
+                        setOutput(s.tokenOut, s.amountOutMin);
                     }
                 }
 
                 if (cmdId === 0x08) {
                     const s = decodeV2SwapExactIn(inputs[i]);
                     if (s) {
-                        if (!inputToken) inputToken = s.tokenIn;
-                        if (!inputAmount) inputAmount = s.amountIn;
-                        outputToken = s.tokenOut;
-                        minOutput = s.amountOutMin;
+                        setInputOnce(s.tokenIn, s.amountIn);
+                        setOutput(s.tokenOut, s.amountOutMin);
                     }
                 }
 
                 if (cmdId === 0x0b) {
                     const w = decodeWrapEth(inputs[i]);
-                    if (w && !inputToken) {
-                        inputToken =
-                            "0x0000000000000000000000000000000000000000";
-                        inputAmount = w.amount;
+                    if (w) {
+                        setInputOnce(
+                            "0x0000000000000000000000000000000000000000",
+                            w.amount,
+                        );
                     }
                 }
 
                 if (cmdId === 0x10) {
                     const v4 = decodeV4Swap(inputs[i]);
                     if (v4) {
-                        if (!inputToken && v4.tokenIn) inputToken = v4.tokenIn;
-                        if (!inputAmount && v4.amountIn)
-                            inputAmount = v4.amountIn;
+                        setInputOnce(v4.tokenIn, v4.amountIn);
                         // Always update output: last swap step wins. A step
                         // that carries the Min. received figure but decoded no
                         // output currency makes the output *undetermined* — it
                         // is neither ETH nor whatever an earlier step named,
                         // and that figure is no longer counted in that token.
-                        if (v4.tokenOut) {
-                            outputToken = v4.tokenOut;
-                        } else if (v4.amountOutMin) {
-                            outputToken = null;
-                        }
-                        if (v4.amountOutMin) minOutput = v4.amountOutMin;
+                        // Equally, a step that names an output currency but no
+                        // minimum leaves Min. received unstated rather than
+                        // keeping an earlier step's figure beside the new
+                        // token. setOutput() is both rules; a step that states
+                        // neither half leaves the output alone.
+                        setOutput(v4.tokenOut, v4.amountOutMin);
                     }
                 }
 
@@ -451,26 +558,14 @@ function decode(data, toAddress, sources) {
             }
         }
 
-        // Resolve token info.
-        //
-        // A null `outputToken` means undetermined, not native ETH, so it is
-        // not handed to tokenInfo() — which maps null to ETH at 18 decimals
-        // for the input side's benefit. Uniswap V4 spells native ETH as
-        // `Currency.wrap(address(0))` (v4-core `type Currency is address`),
-        // and a Currency is ABI-encoded as a plain address word, so every
-        // decode site here gets back the truthy string
-        // "0x0000000000000000000000000000000000000000" for it — never null.
-        // tokenInfo() already names that ETH, and an UNWRAP_WETH output is
-        // caught above, so nothing that genuinely outputs ETH arrives null.
-        // Only a step whose output currency did not decode does, and naming
-        // that ETH states the wrong asset and formats Min. received at the
-        // wrong scale.
+        // Resolve token info. A null token on either side means the calldata
+        // named no currency for it; tokenInfo() refuses rather than calling it
+        // ETH. UNWRAP_WETH is the one output that is ETH without a currency to
+        // decode, and it is answered here rather than left to that rule.
         const inInfo = tokenInfo(inputToken, sources);
         const outInfo = hasUnwrapWeth
             ? { symbol: "ETH", decimals: 18, address: null }
-            : outputToken
-              ? tokenInfo(outputToken, sources)
-              : { symbol: null, decimals: null, address: null };
+            : tokenInfo(outputToken, sources);
 
         const inSymbol = inInfo.symbol;
         const outSymbol = outInfo.symbol;
@@ -488,7 +583,7 @@ function decode(data, toAddress, sources) {
             address: toAddress,
         });
 
-        if (inputToken && inInfo.address) {
+        if (present(inputToken) && present(inInfo.address)) {
             const label = inSymbol
                 ? inSymbol + " (" + inputToken + ")"
                 : inputToken;
@@ -500,18 +595,28 @@ function decode(data, toAddress, sources) {
             });
         } else if (inSymbol === "ETH") {
             details.push({ label: "Token In", value: "ETH (native)" });
+        } else {
+            // Nothing established the input token, so the line says that
+            // rather than going missing or naming a token by default. Same
+            // wording as the Token Out refusal below: the two sides of this
+            // screen must not describe the same condition in two ways.
+            details.push({ label: "Token In", value: UNNAMED_CURRENCY });
         }
 
-        if (inputAmount !== null && inputAmount !== undefined) {
-            const maxUint160 = BigInt(
-                "0xffffffffffffffffffffffffffffffffffffffff",
-            );
-            const isUnlimited = inputAmount >= maxUint160;
-            // An unbounded permit needs no scale to describe, so it is still
-            // named rather than refused.
-            const amount = isUnlimited
-                ? { raw: "Unlimited", display: "Unlimited" }
-                : amountText(inputAmount, inInfo);
+        if (present(inputAmount)) {
+            // Two amounts need no scale to describe and are named rather than
+            // formatted: V4's open delta, which is not a quantity at all (see
+            // OPEN_DELTA), and an unbounded permit. The open-delta test comes
+            // first — the sentinel is not a bigint and cannot be compared with
+            // one.
+            let amount;
+            if (inputAmount === OPEN_DELTA) {
+                amount = { raw: OPEN_DELTA_AMOUNT, display: OPEN_DELTA_AMOUNT };
+            } else if (inputAmount >= MAX_UINT160) {
+                amount = { raw: "Unlimited", display: "Unlimited" };
+            } else {
+                amount = amountText(inputAmount, inInfo);
+            }
             details.push({
                 label: "Amount",
                 value: amount.display,
@@ -524,7 +629,7 @@ function decode(data, toAddress, sources) {
         // entirely, leaving a Min. received figure with nothing saying what is
         // being received. The Token In line above already falls back to the
         // address; this does the same.
-        if (outInfo.address) {
+        if (present(outInfo.address)) {
             const label = outSymbol
                 ? outSymbol + " (" + outInfo.address + ")"
                 : outInfo.address;
@@ -538,20 +643,25 @@ function decode(data, toAddress, sources) {
             details.push({ label: "Token Out", value: outSymbol });
         } else {
             // Nothing established the output token, so the line says that
-            // rather than going missing or naming a token by default. It reads
-            // as a refusal, the same stance unknownDecimalsAmount() takes on a
-            // scale, so a Min. received figure below it is never attached to a
-            // token the calldata did not state.
-            details.push({
-                label: "Token Out",
-                value: "Unknown (not named in the calldata)",
-            });
+            // rather than going missing or naming a token by default, and a
+            // Min. received figure below it is never attached to a token the
+            // calldata did not state.
+            details.push({ label: "Token Out", value: UNNAMED_CURRENCY });
         }
 
-        if (minOutput !== null && minOutput !== undefined) {
+        if (present(minOutput)) {
+            // A zero floor is the one case the user most needs stated: the
+            // swap guarantees nothing back. It is said in words, in the same
+            // register as UNNAMED_CURRENCY, because "0.0000 WETH" reads as an
+            // artifact of the four-decimal rule rather than as "this may
+            // return nothing" — and because it is true at every scale, so it
+            // holds even when the output token's decimals are unknown.
             details.push({
                 label: "Min. received",
-                value: amountText(minOutput, outInfo).display,
+                value:
+                    minOutput === 0n
+                        ? NO_MINIMUM
+                        : amountText(minOutput, outInfo).display,
             });
         }
 

tests/backNavigation.test.js

@@ -153,7 +153,7 @@ describe("Back onto a view the reopened popup never rendered", () => {
 
     test("Back onto the transaction detail renders it", () => {
         reopenedOn("settings", ["main", "transaction"], {
-            viewData: { tx: { hash: "0xdead" } },
+            viewData: { tx: { hash: "0xdead", from: ADDRESS, to: ADDRESS } },
         });
         goBack();
         expect(calls).toEqual(["transactionDetail"]);
@@ -162,7 +162,14 @@ describe("Back onto a view the reopened popup never rendered", () => {
 
     test("Back onto the transaction confirmation restores it", () => {
         reopenedOn("settings", ["main", "confirm-tx"], {
-            viewData: { pendingTx: { to: ADDRESS, amount: "1" } },
+            viewData: {
+                pendingTx: {
+                    token: "ETH",
+                    from: ADDRESS,
+                    to: ADDRESS,
+                    amount: "1",
+                },
+            },
         });
         goBack();
         expect(calls).toEqual(["confirmTx"]);
@@ -171,7 +178,7 @@ describe("Back onto a view the reopened popup never rendered", () => {
 
     test("Back onto the success screen renders it", () => {
         reopenedOn("settings", ["main", "success-tx"], {
-            viewData: { hash: "0xdead" },
+            viewData: { hash: "0xdead", to: ADDRESS },
         });
         goBack();
         expect(calls).toEqual(["successTx"]);
@@ -180,7 +187,7 @@ describe("Back onto a view the reopened popup never rendered", () => {
 
     test("Back onto the failure screen renders it", () => {
         reopenedOn("settings", ["main", "error-tx"], {
-            viewData: { message: "execution reverted" },
+            viewData: { message: "execution reverted", to: ADDRESS },
         });
         goBack();
         expect(calls).toEqual(["errorTx"]);

tests/e2e/run.js

@@ -1525,6 +1525,7 @@ async function goToConfirm(page, { token, balance, amount }) {
     await page.fill("#send-amount", amount);
     await page.click("#btn-send-review");
     await visible(page, "#view-confirm-tx");
+    await assertAddressesFit(page, "the confirmation screen");
 }
 
 // A balance as the main view renders it: balanceLinesForAddress() writes
@@ -3262,6 +3263,8 @@ test("eth_sendTransaction signs the approved transaction and broadcasts it (#183
             JSON.stringify(screen.data),
     );
 
+    await assertAddressesFit(popup, "the dApp transaction prompt");
+
     const broadcastBefore = env.routeOpts.broadcastTransactions.length;
     await popup.fill("#approve-tx-password", PASSWORD);
     await popup.click("#btn-approve-tx");
@@ -3425,6 +3428,206 @@ test("the password never crossed either boundary in this section (#183)", async
     await env.dapp.close();
 });
 
+// ------------------------------------------- address layout (#380)
+//
+// "addresses should never wrap in the common views. this doesn't mean to
+// just change the css, but update the layout itself so the untruncated
+// addresses are shown in full and don't mess up the layout."
+//
+// Every one of these questions is about glyph advances and the width of
+// the box an address landed in, and nothing in the markup answers any of
+// them: a row can hold `white-space: nowrap` and still be too narrow, and
+// the popup's own `overflow-x-hidden` would then hide the evidence by
+// clipping the tail. So they are measured in a real Chromium, on the real
+// rendered views, one assertion per property #380 names:
+//
+//   - the whole address is there (42 characters, no ellipsis)
+//   - it occupies exactly one line box
+//   - it fits its row, so the overflow-x escape hatch never engages
+//   - its row ends inside the popup's content box
+//   - and the document itself does not scroll sideways
+//
+// The narrowest containers the popup has are covered here — the
+// transaction detail wells (`bg-well p-3 mx-1`) and the token contract
+// well — so the wider ones cannot fail while these pass.
+
+// Everything on screen that carries an address, measured in one pass.
+// Views other than the current one are display:none and measure zero, so
+// filtering on width leaves exactly what a user can see right now.
+function addressRowReport(page) {
+    return page.evaluate(() => {
+        const app = document.getElementById("app");
+        const appRight = app.getBoundingClientRect().right;
+        const rows = [];
+        for (const el of document.querySelectorAll(".am-address")) {
+            const box = el.getBoundingClientRect();
+            if (box.width === 0) continue;
+            // Line boxes are counted off the inline content, because the
+            // element's own rect is one box whether the text inside it
+            // wrapped or not. A Range yields a rect per contained node as
+            // well as per line, so it is the distinct tops that count:
+            // a copyable span and the text inside it share one.
+            const range = document.createRange();
+            range.selectNodeContents(el);
+            const tops = new Set(
+                Array.from(range.getClientRects()).map((r) =>
+                    Math.round(r.top),
+                ),
+            );
+            rows.push({
+                text: el.innerText.trim(),
+                lineBoxes: tops.size,
+                overflow: el.scrollWidth - el.clientWidth,
+                overhang: Math.round(box.right - appRight),
+            });
+        }
+        return {
+            rows,
+            pageOverflow:
+                document.documentElement.scrollWidth -
+                document.documentElement.clientWidth,
+        };
+    });
+}
+
+async function assertAddressesFit(page, where) {
+    const report = await addressRowReport(page);
+    assert(
+        report.rows.length > 0,
+        where + ": no address rows were rendered, so nothing was measured",
+    );
+    for (const row of report.rows) {
+        assert(
+            /^0x[0-9a-fA-F]{40}$/.test(row.text),
+            where +
+                ": the address is not shown whole: " +
+                JSON.stringify(row.text),
+        );
+        assert(
+            row.lineBoxes === 1,
+            where +
+                ": " +
+                row.text +
+                " wrapped onto " +
+                row.lineBoxes +
+                " lines",
+        );
+        assert(
+            row.overflow <= 1,
+            where +
+                ": " +
+                row.text +
+                " is " +
+                row.overflow +
+                "px wider than the row holding it",
+        );
+        assert(
+            row.overhang <= 1,
+            where +
+                ": " +
+                row.text +
+                " reaches " +
+                row.overhang +
+                "px past the popup's content box",
+        );
+    }
+    assert(
+        report.pageOverflow <= 0,
+        where + ": the popup scrolls sideways by " + report.pageOverflow + "px",
+    );
+    return report.rows.length;
+}
+
+// Back to Home from wherever the suite above finished, without assuming
+// which screen that was. Every screen the popup can rest on has a Back
+// button, and Home has none, so unwinding until Home shows is the one
+// route that does not depend on the order of the tests before this point.
+async function unwindToHome(page) {
+    for (let i = 0; i < 12; i++) {
+        if (await page.isVisible("#view-main")) return;
+        const back = page
+            .locator(".view:not(.hidden) button", { hasText: "Back" })
+            .first();
+        if ((await back.count()) === 0) break;
+        await back.click();
+        await page.waitForTimeout(150);
+    }
+    await visible(page, "#view-main");
+}
+
+// The reproduction from the issue: a wallet holding more than one address.
+// Every address in the list is a full 42 characters competing with the
+// [info] and [x] controls for one row's width, which is the state the
+// wallet view was reported wrapping in.
+test("a wallet with two addresses lists both in full, unwrapped (#380)", async (env) => {
+    await unwindToHome(env.page);
+
+    const before = await env.page
+        .locator("#wallet-list .btn-addr-info")
+        .count();
+    await env.page.locator("#wallet-list .btn-add-address").first().click();
+    await env.page.waitForFunction(
+        (n) =>
+            document.querySelectorAll("#wallet-list .btn-addr-info").length > n,
+        before,
+        { timeout: 60000 },
+    );
+
+    const shown = await assertAddressesFit(env.page, "the wallet list");
+    assert(
+        shown >= before + 1,
+        "the wallet list measured " +
+            shown +
+            " addresses, fewer than the " +
+            (before + 1) +
+            " it now holds",
+    );
+
+    // The [x] control only exists on a wallet holding more than one
+    // address, so its presence is also the proof the second one landed.
+    const removable = await env.page
+        .locator("#wallet-list .btn-remove-address")
+        .count();
+    assert(removable > 0, "the second address did not reach the wallet list");
+});
+
+test("every common view shows its addresses in full on one line (#380)", async (env) => {
+    await unwindToHome(env.page);
+    await assertAddressesFit(env.page, "Home");
+
+    await env.page.locator("#wallet-list .btn-addr-info").first().click();
+    await visible(env.page, "#view-address");
+    await visible(env.page, "#tx-list .tx-row");
+    await assertAddressesFit(env.page, "the address screen");
+
+    await env.page.click("#btn-receive");
+    await visible(env.page, "#view-receive");
+    await assertAddressesFit(env.page, "the receive screen");
+    await env.page.click("#btn-receive-back");
+    await visible(env.page, "#view-address");
+
+    await env.page.click("#btn-send");
+    await visible(env.page, "#view-send");
+    await assertAddressesFit(env.page, "the send screen");
+    await env.page.click("#btn-send-back");
+    await visible(env.page, "#view-address");
+
+    // The transaction detail screen carries the narrowest address rows in
+    // the popup: its fields sit inside a well that takes another 24px of
+    // padding and 8px of margin off the content width, and the token
+    // contract row there is narrower still.
+    await env.page.locator("#address-balances .balance-row").first().click();
+    await visible(env.page, "#view-address-token");
+    await assertAddressesFit(env.page, "the token screen");
+    await env.page.click("#btn-address-token-back");
+    await visible(env.page, "#view-address");
+
+    await env.page.locator("#tx-list .tx-row").first().click();
+    await visible(env.page, "#view-transaction");
+    await visible(env.page, "#tx-detail-token-contract-section");
+    await assertAddressesFit(env.page, "the transaction detail screen");
+});
+
 // ---------------------------------------------------------------- runner
 
 async function main() {

tests/fabricatedDecimals.test.js

@@ -0,0 +1,282 @@
+// What the balance fetcher stores when the block explorer reports no decimals
+// for a token, and what the approval screens then display.
+//
+// https://git.eeqj.de/sneak/AutistMask/issues/349: `fetchTokenBalances()` did
+// `parseInt(item.token.decimals || "18", 10)` BEFORE writing the row, so a
+// token whose `decimals()` reverts — and which the explorer therefore reports
+// no scale for — was stored with a fabricated 18. Nothing downstream could
+// tell that from a real 18.
+//
+// That matters because it is upstream of two refusals that were already built
+// and already merged. https://git.eeqj.de/sneak/AutistMask/issues/306 made the
+// ERC-20 amount line resolve the real scale or refuse to format, and
+// https://git.eeqj.de/sneak/AutistMask/issues/340 did the same for the swap
+// lines. Both read this stored value as an authoritative source, so the guess
+// walked straight past them: the refusal was intact and simply never fired.
+//
+// So these tests run a real explorer response through the real fetcher and
+// assert on the real approval screens. A test that hand-writes `decimals: null`
+// onto state would pass on the broken build, because the fabrication is in the
+// writer, not the readers.
+
+jest.mock("../src/shared/log", () => ({
+    log: {
+        debugf: () => {},
+        infof: () => {},
+        warnf: () => {},
+        errorf: () => {},
+    },
+    debugFetch: jest.fn(),
+    setRuntimeDebug: () => {},
+    isDebug: () => false,
+}));
+
+global.fetch = jest.fn(() => {
+    throw new Error("tests must not perform network requests");
+});
+
+const { makeStorageStub } = require("./support/storageStub");
+global.chrome = { storage: makeStorageStub() };
+
+const { AbiCoder, Interface } = require("ethers");
+const { ERC20_ABI } = require("../src/shared/constants");
+const { fetchTokenBalances } = require("../src/shared/balances");
+const { debugFetch } = require("../src/shared/log");
+const { state } = require("../src/shared/state");
+const { unknownDecimalsAmount } = require("../src/shared/approvalAmount");
+const { decodeCalldata } = require("../src/popup/views/approval");
+const { TOKEN_BY_ADDRESS } = require("../src/shared/tokenList");
+
+const HOLDER = "0x" + "a".repeat(40);
+const BLOCKSCOUT = "https://blockscout.example/api/v2";
+const ROUTER = "0x66a9893cc07d91d95644aedd05d03f95e1dba8af";
+const RECIPIENT = "0xC0FfEE0000000000000000000000000000c0fFEe";
+const SPENDER = "0x1111111111111111111111111111111111111111";
+// Outside the bundled list and untracked, so the explorer is the only source
+// of a scale for it — which is the case the fabrication was hiding.
+const NOVEL = "0xE2E0000000000000000000000000000000000E2e";
+// In the bundled list, at 18 decimals, for the other side of a swap.
+const WETH = "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2";
+
+// The holding the explorer reports, in base units. Large enough that it does
+// not round to zero even when divided by 10^18, which is what makes it the
+// case the laundering actually REACHED: a smaller holding formatted at the
+// fabricated 18 comes out "0.0", the balance list drops the row as dust, and
+// the approval screens then find no source for the scale and refuse anyway —
+// for the wrong reason, and only by luck.
+const HOLDING = 5000000000000000000n;
+
+// The amount in the dApp's calldata, which is a separate number from the
+// holding. 1,000.00 of a 6-decimal token; formatted at the fabricated 18 it
+// reads 0.000000001, and at a real scale of 0 it reads 1000000000.
+const THOUSAND_AT_SIX = 1000000000n;
+const HALF_WETH = 500000000000000000n;
+
+const erc20Iface = new Interface(ERC20_ABI);
+const coder = AbiCoder.defaultAbiCoder();
+const routerIface = new Interface([
+    "function execute(bytes commands, bytes[] inputs, uint256 deadline)",
+]);
+
+// One Blockscout token-balances row. `token` is spread last so a test can
+// override or blank a field; the base row carries no `decimals` at all, which
+// is exactly what a token whose decimals() reverts produces.
+function row(token = {}, value = HOLDING) {
+    return {
+        value: String(value),
+        token: {
+            type: "ERC-20",
+            address_hash: NOVEL,
+            symbol: "NOVEL",
+            name: "Novel Token",
+            // Well clear of the balance list's own spam floor, so the row is
+            // admitted on its holder count alone: neither the bundled list nor
+            // a tracked entry can supply a scale for it.
+            holders_count: "50000",
+            ...token,
+        },
+    };
+}
+
+function respondWith(items) {
+    debugFetch.mockImplementation(async () => ({
+        ok: true,
+        status: 200,
+        statusText: "OK",
+        json: async () => 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.
+async function fetchOnto(items, trackedTokens = []) {
+    respondWith(items);
+    const balances = await fetchTokenBalances(
+        HOLDER,
+        BLOCKSCOUT,
+        trackedTokens,
+    );
+    state.trackedTokens = trackedTokens;
+    state.wallets = [
+        {
+            name: "Wallet 1",
+            addresses: [
+                { address: HOLDER, balance: "1.0", tokenBalances: balances },
+            ],
+        },
+    ];
+    return balances;
+}
+
+// The ERC-20 approval screen's Amount line, and the swap decoder's.
+function erc20AmountLine(data, tokenAddress) {
+    return decodeCalldata(data, tokenAddress).details.find(
+        (d) => d.label === "Amount",
+    ).value;
+}
+
+function swapAmountLine(data) {
+    return decodeCalldata(data, ROUTER).details.find(
+        (d) => d.label === "Amount",
+    ).value;
+}
+
+function transferData(amount) {
+    return erc20Iface.encodeFunctionData("transfer", [RECIPIENT, amount]);
+}
+
+function approveData(amount) {
+    return erc20Iface.encodeFunctionData("approve", [SPENDER, amount]);
+}
+
+function swapData(tokenIn, amountIn, tokenOut, amountOutMin) {
+    const input = coder.encode(
+        ["address", "uint256", "uint256", "address[]", "bool"],
+        [RECIPIENT, amountIn, amountOutMin, [tokenIn, tokenOut], true],
+    );
+    return routerIface.encodeFunctionData("execute", [
+        "0x08",
+        [input],
+        9999999999n,
+    ]);
+}
+
+beforeEach(() => {
+    debugFetch.mockReset();
+    state.trackedTokens = [];
+    state.wallets = [];
+});
+
+describe("what fetchTokenBalances stores for an absent scale", () => {
+    test("the token is not in the bundled list, so the explorer is the only source", () => {
+        expect(TOKEN_BY_ADDRESS.has(NOVEL.toLowerCase())).toBe(false);
+    });
+
+    test("an absent decimals is stored as null, not as 18", async () => {
+        const balances = await fetchOnto([row()]);
+        expect(balances).toHaveLength(1);
+        expect(balances[0].decimals).toBeNull();
+    });
+
+    test("an explicit null decimals is stored as null too", async () => {
+        const balances = await fetchOnto([row({ decimals: null })]);
+        expect(balances[0].decimals).toBeNull();
+    });
+
+    // The same explorer row twice, differing only in whether it reports a
+    // scale of 18. Before the fix both stored 18 and no reader could tell
+    // which one had actually been reported.
+    test("a real 18 is stored as 18, and so is distinguishable from absent", async () => {
+        const real = await fetchOnto([row({ decimals: "18" })]);
+        expect(real[0].decimals).toBe(18);
+        expect(real[0].balance).toBe("5.0");
+        const absent = await fetchOnto([row()]);
+        expect(absent[0].decimals).toBeNull();
+        expect(real[0].decimals).not.toBe(absent[0].decimals);
+    });
+
+    // The falsy-collapse trap of
+    // https://git.eeqj.de/sneak/AutistMask/issues/246. `decimals || "18"` reads
+    // a real scale of zero as absent and then as eighteen, which is eighteen
+    // orders of magnitude of error in the direction that displays as nothing.
+    test("a real scale of zero is stored as zero, not collapsed", async () => {
+        for (const reported of ["0", 0]) {
+            const balances = await fetchOnto([row({ decimals: reported })]);
+            expect(balances[0].decimals).toBe(0);
+            expect(balances[0].balance).toBe("5000000000000000000.0");
+        }
+    });
+
+    test("no quantity is stated for a holding whose scale is unknown", async () => {
+        const balances = await fetchOnto([row()]);
+        // Not "0.0": the holding is real and nonzero, and a zero here is the
+        // same lie the approval screens refuse to tell.
+        expect(balances[0].balance).toBeNull();
+    });
+
+    // Zero base units is zero tokens at every scale, so this filter never
+    // needed a scale in the first place and does not acquire one now.
+    test("a holding of zero base units is still dropped without a scale", async () => {
+        expect(await fetchOnto([row({}, 0n)])).toEqual([]);
+    });
+
+    test("the bundled list still supplies a quantity the explorer omitted", async () => {
+        const balances = await fetchOnto([
+            row({ address_hash: WETH, symbol: "WETH" }),
+        ]);
+        // The stored decimals stay the explorer's own answer — absent. Copying
+        // another source in here would make explorerDecimals()'s disagreement
+        // check compare something other than explorer values.
+        expect(balances[0].decimals).toBeNull();
+        // The displayed quantity still comes out right, because the bundled
+        // list knows this token's scale and outranks the explorer anyway.
+        expect(balances[0].balance).toBe("5.0");
+    });
+});
+
+describe("the ERC-20 approval line reaches its refusal", () => {
+    test("a transfer of a token the explorer gave no scale for is not formatted", async () => {
+        await fetchOnto([row()]);
+        const line = erc20AmountLine(transferData(THOUSAND_AT_SIX), NOVEL);
+        expect(line).toBe(unknownDecimalsAmount(THOUSAND_AT_SIX));
+        // The defect: a fabricated 18 renders this as 0.000000001, a quantity,
+        // and a wrong one.
+        expect(line).not.toMatch(/^0\./);
+    });
+
+    test("an approve of the same token is not formatted either", async () => {
+        await fetchOnto([row()]);
+        const line = erc20AmountLine(approveData(THOUSAND_AT_SIX), NOVEL);
+        expect(line).toBe(unknownDecimalsAmount(THOUSAND_AT_SIX));
+        expect(line).not.toMatch(/^0\./);
+    });
+
+    test("a scale the explorer did report still formats", async () => {
+        await fetchOnto([row({ decimals: "6" })]);
+        expect(erc20AmountLine(transferData(THOUSAND_AT_SIX), NOVEL)).toBe(
+            "1000.0000",
+        );
+    });
+});
+
+describe("the swap approval line reaches its refusal", () => {
+    test("a swap of a token the explorer gave no scale for is not formatted", async () => {
+        await fetchOnto([row()]);
+        const line = swapAmountLine(
+            swapData(NOVEL, THOUSAND_AT_SIX, WETH, HALF_WETH),
+        );
+        expect(line).toBe(unknownDecimalsAmount(THOUSAND_AT_SIX));
+        expect(line).not.toMatch(/^0\./);
+    });
+
+    test("a scale the explorer did report still formats", async () => {
+        await fetchOnto([row({ decimals: "6" })]);
+        expect(
+            swapAmountLine(swapData(NOVEL, THOUSAND_AT_SIX, WETH, HALF_WETH)),
+        ).toBe("1000.0000");
+    });
+});
+
+test("no test in this file performed a network request", () => {
+    expect(global.fetch).not.toHaveBeenCalled();
+});

tests/manifest.test.js

@@ -47,6 +47,12 @@ const fs = require("fs");
 const path = require("path");
 
 const MANIFEST_DIR = path.join(__dirname, "..", "manifest");
+const ROOT = path.join(__dirname, "..");
+
+// The sizes both stores and both toolbars ask for.
+const EXPECTED_ICON_SIZES = ["16", "32", "48", "128"];
+
+const PNG_SIGNATURE = Buffer.from("89504e470d0a1a0a", "hex");
 
 const EXPECTED_DIRECTIVES = {
     "default-src": ["'self'"],
@@ -115,6 +121,51 @@ function assertPolicy(policy) {
     }
 }
 
+// The declared icons, in both manifests.
+//
+// Without an "icons" block a browser draws a generic puzzle piece in the
+// toolbar for this extension, which is both the first thing the user sees and
+// how a real extension is told apart from a look-alike. Declaring one is not
+// enough on its own: an entry naming a file that is not in the tree ships a
+// reference to nothing, so the referenced bytes are read here and required to
+// be a PNG of the size the entry claims. build.js copies these into each
+// browser directory, relative to it, and script/lib/package.js then refuses to
+// build an archive that does not contain everything the manifest names.
+function assertIcons(target) {
+    const icons = readManifest(target).icons;
+    expect(Object.keys(icons).sort()).toEqual(EXPECTED_ICON_SIZES.sort());
+    for (const size of EXPECTED_ICON_SIZES) {
+        const ref = icons[size];
+        expect([size, ref]).toEqual([size, `icons/icon${size}.png`]);
+
+        const bytes = fs.readFileSync(path.join(ROOT, ref));
+        expect(bytes.subarray(0, 8)).toEqual(PNG_SIGNATURE);
+        // IHDR width and height, at fixed offsets right after the signature
+        // and the chunk header.
+        expect([ref, bytes.readUInt32BE(16), bytes.readUInt32BE(20)]).toEqual([
+            ref,
+            Number(size),
+            Number(size),
+        ]);
+    }
+}
+
+describe("declared icons", () => {
+    test("chrome declares real icons at every size", () => {
+        assertIcons("chrome");
+    });
+
+    test("firefox declares real icons at every size", () => {
+        assertIcons("firefox");
+    });
+
+    test("both targets declare the same icons", () => {
+        expect(readManifest("firefox").icons).toEqual(
+            readManifest("chrome").icons,
+        );
+    });
+});
+
 describe("shipped Content Security Policy", () => {
     // MV3 takes an object and applies extension_pages to the popup and the
     // background service worker, which is where libsodium runs.

tests/packaging.test.js

@@ -90,6 +90,26 @@ describe("archive self-containment", () => {
         );
     });
 
+    // Toolbar icons are the other file the manifest names and no bundler
+    // emits, so an archive built without them would carry a manifest whose
+    // "icons" resolve to nothing and a browser would fall back to a generic
+    // placeholder without saying so.
+    test("a manifest naming an icon that is not in the archive fails", () => {
+        const { members, read } = archiveOf({
+            "manifest.json": JSON.stringify({
+                ...MINIMAL_MANIFEST,
+                icons: { 16: "icons/icon16.png", 128: "icons/icon128.png" },
+            }),
+            "src/popup/index.html": "<html></html>",
+            "src/popup/index.js": "//",
+            "src/background/index.js": "//",
+            "icons/icon16.png": "PNG",
+        });
+        expect(() => checkSelfContained("chrome", members, read)).toThrow(
+            /would not be self-contained.*icons\/icon128\.png/s,
+        );
+    });
+
     test("an archive with no manifest.json at its root fails", () => {
         const { members, read } = archiveOf({ "src/popup/index.js": "//" });
         expect(() => checkSelfContained("chrome", members, read)).toThrow(

tests/persistedEntryFloors.test.js

@@ -0,0 +1,404 @@
+// A persisted container that is checked while its ENTRIES are dereferenced
+// unchecked (https://git.eeqj.de/sneak/AutistMask/issues/362).
+//
+// https://git.eeqj.de/sneak/AutistMask/issues/311 settled the idiom — floor the
+// container AND its entries, dropping anything that cannot be safely
+// dereferenced — and applied it to trackedTokens and tokenBalances. These are
+// the fields it did not reach.
+//
+// allowedSites is the worst shape in the codebase, and it is what the boot
+// tests below measure: a stored `{"0x…": "notalist"}` passes the gate, renders
+// a WORKING popup, and then throws `base.map is not a function` inside
+// saveState()'s merge — so every save from then on fails while the UI looks
+// entirely healthy and the user goes on operating a wallet that is persisting
+// nothing. A blank popup is at least visibly broken; this is not. So the
+// assertion here is never merely "the popup rendered": it is "the popup
+// rendered AND the write actually landed in storage".
+//
+// Observed at ad6aa7b, with the floors below removed:
+//   allowedSites: {"0x…": "notalist"}   -> views=["main"], errors=[], and
+//       storage.set NEVER called: the stored record kept no schemaVersion, so
+//       nothing the user did was persisted.
+//   fraudContracts: "0x…"               -> renderSendTokenSelect() threw
+//       "(state.fraudContracts || []).map is not a function"
+//   fraudContracts: [42]                -> threw "a.toLowerCase is not a
+//       function"
+//   selectedToken: 42 (restoring onto address-token) -> views=[], errors=
+//       ["tokenId.toLowerCase is not a function"] — a blank popup.
+
+const { normalizePersisted } = require("../src/shared/persistedState");
+const { makeStorageStub } = require("./support/storageStub");
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    ADDRESS,
+    TOKEN_ADDRESS,
+} = require("./support/popupBoot");
+
+// One extension page: a fresh module registry over the given storage. state.js
+// resolves the storage API at require time, so the stub has to be installed
+// before the module is loaded.
+function loadStateModule(storage) {
+    jest.resetModules();
+    globalThis.chrome = { storage: { local: storage.local } };
+    return require("../src/shared/state");
+}
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+// ------------------------------------------------------- the floor itself
+
+describe("the floor under allowedSites and deniedSites", () => {
+    for (const field of ["allowedSites", "deniedSites"]) {
+        test(`${field} that is not a record becomes an empty record`, () => {
+            for (const bad of ["nope", 42, true, [ADDRESS], null]) {
+                expect(normalizePersisted({ [field]: bad })[field]).toEqual({});
+            }
+        });
+
+        test(`an ${field} entry whose value is not a hostname list is dropped`, () => {
+            for (const bad of ["dapp.example", 42, null, { a: 1 }, true]) {
+                expect(
+                    normalizePersisted({ [field]: { [ADDRESS]: bad } })[field],
+                ).toEqual({});
+            }
+        });
+
+        test(`a hostname that is not text is dropped from an ${field} entry`, () => {
+            expect(
+                normalizePersisted({
+                    [field]: { [ADDRESS]: [42, null, "dapp.example", {}] },
+                })[field],
+            ).toEqual({ [ADDRESS]: ["dapp.example"] });
+        });
+
+        test(`a real ${field} map survives, copied not shared`, () => {
+            const saved = { [field]: { [ADDRESS]: ["dapp.example"] } };
+
+            const out = normalizePersisted(saved);
+
+            expect(out[field]).toEqual(saved[field]);
+            expect(out[field]).not.toBe(saved[field]);
+            expect(out[field][ADDRESS]).not.toBe(saved[field][ADDRESS]);
+        });
+
+        test(`a good ${field} entry beside a malformed one survives`, () => {
+            const out = normalizePersisted({
+                [field]: { [ADDRESS]: ["dapp.example"], [TOKEN_ADDRESS]: 42 },
+            });
+
+            expect(out[field]).toEqual({ [ADDRESS]: ["dapp.example"] });
+        });
+
+        test(`a stored own "__proto__" key in ${field} is dropped`, () => {
+            // JSON can carry the key. It can never be a wallet address, so it
+            // grants and denies nothing and goes the way of every other key
+            // whose value is unusable; keeping it would only keep a value that
+            // saveState()'s merge hands to the prototype setter on the next
+            // write.
+            const saved = JSON.parse(
+                '{"' + field + '":{"__proto__":["evil.invalid"]}}',
+            );
+
+            const out = normalizePersisted(saved);
+
+            expect(Object.getPrototypeOf(out[field])).toBe(Object.prototype);
+            expect(Object.keys(out[field])).toEqual([]);
+        });
+    }
+});
+
+describe('a stored own "__proto__" key surviving a save', () => {
+    // The floor writes map keys with defineProperty; saveState()'s merge is one
+    // layer downstream of it and used to write them with plain assignment,
+    // which hands "__proto__" to the prototype setter and records no entry.
+    // networkEndpoints is where a key that is not a known id is deliberately
+    // KEPT, so it is where that undoing shows.
+    test("does not move a prototype or vanish from networkEndpoints", async () => {
+        const profile = unversionedValidProfile();
+        profile.networkEndpoints = JSON.parse(
+            '{"__proto__":{"rpcUrl":"https://kept.invalid"}}',
+        );
+        const storage = makeStorageStub({ autistmask: profile });
+        const { state, loadState, saveState } = loadStateModule(storage);
+
+        await loadState();
+        state.theme = "dark";
+        await saveState();
+
+        // Not compared against Object.prototype by identity: the storage stub
+        // clones through structuredClone, which builds the result in the host
+        // realm, so the two Object.prototypes are different objects.
+        const stored = storage.read("autistmask").networkEndpoints;
+        expect(Object.getPrototypeOf(stored).rpcUrl).toBeUndefined();
+        expect(Object.keys(stored)).toContain("__proto__");
+    });
+});
+
+describe("the floor under fraudContracts", () => {
+    test("fraudContracts that is not a list becomes an empty list", () => {
+        for (const bad of ["nope", 42, true, { a: 1 }]) {
+            expect(
+                normalizePersisted({ fraudContracts: bad }).fraudContracts,
+            ).toEqual([]);
+        }
+    });
+
+    test("a fraudContracts entry that is not text is dropped", () => {
+        expect(
+            normalizePersisted({
+                fraudContracts: [42, null, TOKEN_ADDRESS, {}, []],
+            }).fraudContracts,
+        ).toEqual([TOKEN_ADDRESS]);
+    });
+
+    test("a real fraudContracts list survives, copied not shared", () => {
+        const saved = { fraudContracts: [TOKEN_ADDRESS] };
+
+        const out = normalizePersisted(saved);
+
+        expect(out.fraudContracts).toEqual(saved.fraudContracts);
+        expect(out.fraudContracts).not.toBe(saved.fraudContracts);
+    });
+});
+
+describe("the floor under selectedToken", () => {
+    // Found by the sweep for this defect class, not named in the issue: the
+    // restore gate in src/popup/viewRouter.js checks truthiness only, and both
+    // src/popup/views/addressToken.js and src/popup/views/receive.js then
+    // dereference it as text.
+    test("a selectedToken that is not text becomes null", () => {
+        for (const bad of [42, true, { a: 1 }, [TOKEN_ADDRESS]]) {
+            expect(
+                normalizePersisted({ selectedToken: bad }).selectedToken,
+            ).toBeNull();
+        }
+    });
+
+    test("a real selectedToken survives; the empty string becomes null", () => {
+        expect(
+            normalizePersisted({ selectedToken: TOKEN_ADDRESS }).selectedToken,
+        ).toBe(TOKEN_ADDRESS);
+        expect(normalizePersisted({ selectedToken: "ETH" }).selectedToken).toBe(
+            "ETH",
+        );
+        expect(
+            normalizePersisted({ selectedToken: "" }).selectedToken,
+        ).toBeNull();
+    });
+});
+
+// ----------------------------------------- what the user actually gets
+
+describe("a malformed allowedSites entry", () => {
+    const MALFORMED = [
+        { name: "a string", value: "notalist" },
+        { name: "a number", value: 42 },
+        { name: "a record", value: { hostnames: ["dapp.example"] } },
+    ];
+
+    for (const { name, value } of MALFORMED) {
+        test(`whose value is ${name}: a working popup whose writes persist`, async () => {
+            const env = await bootPopup(
+                unversionedValidProfile({
+                    allowedSites: { [ADDRESS]: value },
+                }),
+            );
+
+            expect({
+                visibleViews: env.visibleViews(),
+                errors: env.pageErrors,
+            }).toEqual({ visibleViews: ["main"], errors: [] });
+
+            // The half that matters. A popup that renders and never persists
+            // again is worse than one that renders nothing, because nothing
+            // tells the user. The version stamp is proof a write landed: it
+            // is absent from the stored record until saveState() writes one.
+            expect(env.storage.set).toHaveBeenCalled();
+            const stored = env.storage.read("autistmask");
+            expect(stored.schemaVersion).toBe(1);
+            expect(stored.wallets[0].encryptedSecret).toBe(
+                "encrypted-secret-1",
+            );
+            expect(stored.allowedSites).toEqual({});
+        });
+    }
+
+    test("the well-formed entries beside it keep working", async () => {
+        const env = await bootPopup(
+            unversionedValidProfile({
+                allowedSites: {
+                    [ADDRESS]: ["dapp.example"],
+                    [TOKEN_ADDRESS]: "notalist",
+                },
+            }),
+        );
+
+        expect(env.pageErrors).toEqual([]);
+        expect(env.storage.read("autistmask").allowedSites).toEqual({
+            [ADDRESS]: ["dapp.example"],
+        });
+    });
+
+    test("a later save still lands, not just the first", async () => {
+        // The failure this closes was in the MERGE, which runs on every save
+        // against whatever is in storage at the time. One write landing is not
+        // enough: the field has to stay mergeable.
+        const storage = makeStorageStub({
+            autistmask: unversionedValidProfile({
+                allowedSites: { [ADDRESS]: "notalist" },
+            }),
+        });
+        const { state, loadState, saveState } = loadStateModule(storage);
+
+        await loadState();
+        state.theme = "dark";
+        await saveState();
+        state.utcTimestamps = true;
+        await saveState();
+
+        const stored = storage.read("autistmask");
+        expect(stored.theme).toBe("dark");
+        expect(stored.utcTimestamps).toBe(true);
+        expect(stored.allowedSites).toEqual({});
+        expect(stored.wallets[0].encryptedSecret).toBe("encrypted-secret-1");
+    });
+});
+
+describe("a malformed fraudContracts", () => {
+    // The send screen, which is where this one lands: the boot path only
+    // reaches fraudContracts through loadHomeTxs(), which catches, so the
+    // consequence is an unusable send screen rather than silent data loss.
+    function stubSendDocument() {
+        const select = { innerHTML: "", children: [] };
+        select.appendChild = (child) => select.children.push(child);
+        globalThis.document = {
+            getElementById: (id) => (id === "send-token" ? select : null),
+            createElement: () => ({ value: "", textContent: "" }),
+        };
+        return select;
+    }
+
+    const HELD = {
+        address: TOKEN_ADDRESS,
+        symbol: "AAA",
+        decimals: 18,
+        balance: "12.5",
+        holders: 50000,
+    };
+
+    async function sendScreenTokens(fraudContracts) {
+        const storage = makeStorageStub({
+            autistmask: unversionedValidProfile({ fraudContracts }),
+        });
+        const { loadState } = loadStateModule(storage);
+        await loadState();
+        const select = stubSendDocument();
+        const { renderSendTokenSelect } = require("../src/popup/views/send");
+
+        renderSendTokenSelect({ address: ADDRESS, tokenBalances: [HELD] });
+
+        return select.children.map((opt) => opt.value);
+    }
+
+    for (const bad of ["notalist", 42, { a: 1 }, [42], [null], [{}]]) {
+        test(`${JSON.stringify(bad)}: a usable send screen`, async () => {
+            await expect(sendScreenTokens(bad)).resolves.toEqual([
+                TOKEN_ADDRESS,
+            ]);
+        });
+    }
+
+    test("a real fraud entry beside a malformed one still hides its token", async () => {
+        await expect(
+            sendScreenTokens([42, TOKEN_ADDRESS.toLowerCase()]),
+        ).resolves.toEqual([]);
+    });
+});
+
+describe("a malformed selectedToken", () => {
+    test("does not blank the popup on restore", async () => {
+        const env = await bootPopup(
+            unversionedValidProfile({
+                currentView: "address-token",
+                selectedWallet: 0,
+                selectedAddress: 0,
+                selectedToken: 42,
+                viewStack: ["main", "address"],
+            }),
+        );
+
+        expect({
+            visibleViews: env.visibleViews(),
+            errors: env.pageErrors,
+        }).toEqual({ visibleViews: ["main"], errors: [] });
+    });
+});
+
+// --------------------------------------------- a save that fails is told
+
+describe("a save that fails", () => {
+    function failingStorage(profile) {
+        const storage = makeStorageStub({ autistmask: profile });
+        const realSet = storage.local.set;
+        storage.local.set = jest.fn(async () => {
+            throw new Error("QUOTA_BYTES quota exceeded");
+        });
+        storage.restoreWrites = () => {
+            storage.local.set = realSet;
+        };
+        return storage;
+    }
+
+    test("is reported, not swallowed by the save queue", async () => {
+        const storage = failingStorage(unversionedValidProfile());
+        const { state, loadState, saveState, onSaveFailure } =
+            loadStateModule(storage);
+        const failures = [];
+        onSaveFailure((e) => failures.push(String(e && e.message)));
+
+        await loadState();
+        state.theme = "dark";
+        // Not awaited, which is how showView() saves on every navigation and
+        // how the failure used to disappear entirely.
+        saveState();
+        for (let i = 0; i < 50; i++) await Promise.resolve();
+
+        expect(failures).toEqual(["QUOTA_BYTES quota exceeded"]);
+    });
+
+    test("still rejects for a caller that awaits it", async () => {
+        const storage = failingStorage(unversionedValidProfile());
+        const { state, loadState, saveState, onSaveFailure } =
+            loadStateModule(storage);
+        onSaveFailure(() => {});
+
+        await loadState();
+        state.theme = "dark";
+
+        await expect(saveState()).rejects.toThrow("QUOTA_BYTES");
+    });
+
+    test("puts a banner on the popup saying nothing is being saved", async () => {
+        const env = await bootPopup(undefined, {
+            storage: failingStorage(unversionedValidProfile()),
+        });
+
+        // The popup is still usable — the point is that it no longer looks
+        // healthy while silently persisting nothing.
+        expect(env.visibleViews()).toEqual(["main"]);
+        const banner = env.node("save-failure-banner");
+        expect(banner).not.toBeNull();
+        expect(banner.textContent).toContain("NOT SAVED");
+        expect(banner.textContent).toContain("QUOTA_BYTES quota exceeded");
+    });
+
+    test("no banner appears on a popup whose saves work", async () => {
+        const env = await bootPopup(unversionedValidProfile());
+
+        expect(env.node("save-failure-banner")).toBeNull();
+    });
+});

tests/persistedFieldContract.test.js

@@ -0,0 +1,864 @@
+// What the floor under each persisted field actually guarantees — as a table
+// that RUNS, one row per field.
+//
+// This file replaces a hand-written per-field justification in the header of
+// src/shared/stateSchema.js. That comment shipped a false claim in three
+// consecutive changes: every author wrote plausible prose about thirty fields,
+// every reviewer re-derived it by hand, and it kept being wrong in a different
+// place each time. The artifact was the problem. A claim nobody can execute is
+// worse than no claim, because it is believed.
+//
+// So the claim is a row here instead:
+//
+//   KIND.REFUSED   assertStateUsable() refuses the record outright. Proven by
+//                  stateProblem() naming a problem for every hostile value.
+//   KIND.ENTRIES   normalizePersisted() floors the container AND its entries.
+//                  Proven by holds() over the normalized value.
+//   KIND.SCALAR    normalizePersisted() floors it to one scalar type, or to a
+//                  fixed fallback. Proven the same way.
+//   KIND.LOOSE     `saved.x || default`, no type check at all. The claim is
+//                  that no structural dereference of it is reachable from a
+//                  stored record — which cannot be argued, only driven, so the
+//                  proof is a boot of the REAL popup entry point over a stored
+//                  record carrying the hostile value, ONTO EVERY RESTORABLE
+//                  VIEW. Home is not where this class of defect lives.
+//
+// Every row is driven through a boot regardless of kind, but only a LOOSE row
+// (or a row that sets `alsoSweep`) is swept across the restore path: that is
+// what declaring LOOSE costs. ENTRIES and SCALAR rows are proven by their
+// holds() instead, because a floored value is not hostile by the time a
+// renderer sees it. A LOOSE row must additionally prove it is loose: if
+// someone floors the field — even partially — and leaves the row saying LOOSE,
+// the "survives verbatim" assertion fails. A field added to PERSISTED_FIELDS
+// with no row fails the first test in the file.
+//
+// The sweep is what makes a LOOSE row falsifiable, so read how it is driven
+// before trusting it. A row the ROUTER reads (`routes`) gets its own boot per
+// view, because a hostile value in it legitimately changes which view renders.
+// Every other swept field is corrupted on the SAME boot, one boot per view per
+// slot, and that boot has to land on the view it stored — so a field that does
+// move the routing cannot hide in the crowd. Every swept field is driven at
+// BOTH POLARITIES: a value nothing in src/ writes is a wrong-typed one and so
+// always truthy, which leaves `if (!state.x) { state.y.deref() }` unentered on
+// the very boot that corrupts x. The last slot is the falsy one for that
+// reason, and a field that cannot be falsy after the floor says so in its row
+// and is proven so.
+//
+// READ THE CLAIM NARROWLY. What this file proves is: NO STRUCTURAL
+// DEREFERENCE ON THE CODE PATHS A WHOLLY-CORRUPTED PROFILE TAKES. That is not
+// every path a stored record takes, and the difference is the whole of what
+// this file does not cover:
+//
+//   - Only the values in the table, in the SLOT arrangement below: four value
+//     combinations per view, not the product of twelve fields. A dereference
+//     reached only under a pairing no slot produces is not driven at all.
+//   - Only what a stored record reaches by ITSELF. A view only forward
+//     navigation opens, and anything behind a click, is not driven.
+//   - Nothing about the paths a HEALTHY profile takes, which is most of the
+//     popup. This file is a floor under one defect class, not a proof about
+//     the renderers.
+//
+// Within that boundary it is unconditional: if one of these boots leaves the
+// popup unhealthy or off the view it stored, this file goes red — including
+// when it takes two corrupted fields at once, because the verdict is the
+// combined boot itself and the per-field re-boot below can only decorate the
+// message. That last part is the one thing an earlier version got wrong: it
+// asserted on the per-field list, so an observed dead popup that no single
+// field reproduced was reported green.
+//
+// Booting every field separately at every value would be several hundred boots
+// and most of the suite's budget; this is forty-four. Widening it further is
+// out of scope — proving no field is dereferenced on any reachable render path
+// is exhaustive verification of the popup, not a floor under a stored record.
+//
+// The three claims this replaced, all false, all caught here by construction:
+// rpcUrl reaching `new JsonRpcProvider()` (a synchronous throw, not a caught
+// request); viewData's ENTRIES being dereferenced by four restore branches
+// that gate on one truthy field each; and selectedWallet, where a stale
+// integer index is the SAFE case and `wallets["map"]` is the throwing one.
+
+const {
+    PERSISTED_FIELDS,
+    normalizePersisted,
+} = require("../src/shared/persistedState");
+const { stateProblem } = require("../src/shared/stateSchema");
+const { RESTORABLE_VIEWS } = require("../src/shared/restorableViews");
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    ADDRESS,
+    TOKEN_ADDRESS,
+} = require("./support/popupBoot");
+
+const KIND = {
+    REFUSED: "refused by the gate",
+    ENTRIES: "container and entries type-checked",
+    SCALAR: "scalar type-checked",
+    LOOSE: "loosely floored; safety proven by driving the popup",
+};
+
+const isText = (v) => typeof v === "string";
+const isRecord = (v) =>
+    typeof v === "object" && v !== null && !Array.isArray(v);
+const isIndexOrNull = (v) => v === null || (Number.isInteger(v) && v >= 0);
+const isTextOrNull = (v) => v === null || (isText(v) && v !== "");
+const everyEntry = (v, fn) => Array.isArray(v) && v.every(fn);
+
+// A row is SWEPT — driven onto every restorable view rather than only onto
+// Home — when its claim is that no restore path dereferences the field. That
+// is what LOOSE means. The two index rows opt in with `alsoSweep` although
+// they are floored, because the restore path is precisely why they gained a
+// floor and the sweep is the regression guard on it.
+const swept = (row) => row.kind === KIND.LOOSE || Boolean(row.alsoSweep);
+
+// Every value a swept row drives through a boot: the hostile set, plus the
+// falsy slot that gives the field its other polarity. `hostile` values are all
+// TRUTHY by nature — a value nothing in src/ writes is a wrong-typed one, and
+// wrong-typed values are objects, non-empty strings and non-zero numbers. A
+// field that is only ever truthy on the boot that corrupts it cannot falsify
+// `if (!state.x) { state.y.deref() }`, so the falsy slot is not optional.
+const sweptValues = (row) => [...row.hostile, ...(row.falsy || [])];
+
+// ------------------------------------------------------------------ the table
+//
+// `hostile` is values a stored record can carry that nothing in src/ ever
+// writes. Each one is driven through the floor AND through a real popup boot —
+// and, for a swept row, through one boot per restorable view — so keep the
+// list short and pointed. `floorOnly` is extra values checked against the
+// floor alone, which is pure and free. `hostileRestore` is extra values driven
+// through the restore path only, for a value that means nothing until a
+// particular branch's gate has let it past.
+//
+// `falsy` is the other POLARITY of a swept field, driven for the same reason.
+// It is not a value src/ never writes — for three of these fields it is the
+// DEFAULT_STATE default, which is the branch every ordinary install takes —
+// and that is the point: without it, a dereference behind `if (!state.x)` is
+// unreachable on the one boot that corrupts x. A swept row that cannot supply
+// one says `neverFalsy` instead, which is proven rather than asserted: every
+// falsy value stored under that field comes back TRUTHY from the floor, so no
+// `!state.x` branch is reachable from a stored record at all.
+
+const CONTRACT = [
+    {
+        field: "wallets",
+        kind: KIND.REFUSED,
+        hostile: [42, "notastructure", { a: 1 }, [null], [{ addresses: 1 }]],
+    },
+    {
+        field: "networkId",
+        kind: KIND.REFUSED,
+        hostile: [42, "notanetwork", { a: 1 }, "__proto__"],
+    },
+    {
+        field: "trackedTokens",
+        kind: KIND.ENTRIES,
+        hostile: [42, "notalist", { a: 1 }],
+        floorOnly: [[1, 2], [null], [{}], [[TOKEN_ADDRESS]]],
+        holds: (v) => everyEntry(v, (t) => isRecord(t) && isText(t.address)),
+    },
+    {
+        field: "allowedSites",
+        kind: KIND.ENTRIES,
+        hostile: [42, "notarecord", { [ADDRESS]: "notalist" }],
+        floorOnly: [
+            [ADDRESS],
+            { [ADDRESS]: 42 },
+            { [ADDRESS]: [42, null, {}] },
+            JSON.parse('{"__proto__":["evil.invalid"]}'),
+        ],
+        holds: siteMapHolds,
+    },
+    {
+        field: "deniedSites",
+        kind: KIND.ENTRIES,
+        hostile: [42, "notarecord", { [ADDRESS]: "notalist" }],
+        floorOnly: [
+            [ADDRESS],
+            { [ADDRESS]: 42 },
+            { [ADDRESS]: [42, null, {}] },
+            JSON.parse('{"__proto__":["evil.invalid"]}'),
+        ],
+        holds: siteMapHolds,
+    },
+    {
+        field: "fraudContracts",
+        kind: KIND.ENTRIES,
+        hostile: [42, "notalist", { a: 1 }],
+        floorOnly: [[42], [null], [{}], [[TOKEN_ADDRESS]]],
+        holds: (v) => everyEntry(v, isText),
+    },
+    {
+        field: "viewStack",
+        kind: KIND.ENTRIES,
+        hostile: [42, "notalist", ["main", "show-phrase", "settings"]],
+        floorOnly: [[1, 2], [null], [{}], ["export-privkey"]],
+        // Truncated at the first entry the popup will not reopen onto, rather
+        // than filtered: every surviving entry's Back target has to stay the
+        // one it had. restorableStack() may also substitute ["main"] under a
+        // view restored below the root, so this is the one ENTRIES field whose
+        // result is not always a subset of what was stored.
+        holds: (v) => everyEntry(v, (e) => RESTORABLE_VIEWS.has(e)),
+    },
+    {
+        field: "networkEndpoints",
+        kind: KIND.ENTRIES,
+        hostile: [42, "notarecord", { mainnet: "notapair" }],
+        floorOnly: [
+            [1, 2],
+            { mainnet: { rpcUrl: 42, blockscoutUrl: {} } },
+            { mainnet: { rpcUrl: "", blockscoutUrl: [] } },
+            { sepolia: 42 },
+        ],
+        // Entries are coerced rather than dropped: an unknown network id is
+        // KEPT, so a profile that has been on a build with more networks does
+        // not lose their endpoints here. What is floored is the two URL fields
+        // inside the pair, which applyChainSwitchFields() assigns straight onto
+        // s.rpcUrl / s.blockscoutUrl on the next switch.
+        holds: (v) =>
+            isRecord(v) &&
+            Object.keys(v).every((id) => {
+                const pair = v[id];
+                return (
+                    isRecord(pair) &&
+                    (pair.rpcUrl === undefined ||
+                        (isText(pair.rpcUrl) && pair.rpcUrl !== "")) &&
+                    (pair.blockscoutUrl === undefined ||
+                        (isText(pair.blockscoutUrl) &&
+                            pair.blockscoutUrl !== ""))
+                );
+            }),
+    },
+    {
+        field: "rpcUrl",
+        kind: KIND.SCALAR,
+        hostile: [42, true, { a: 1 }],
+        floorOnly: [[], "", null],
+        holds: (v) => isText(v) && v !== "",
+        // The claim this row replaced said a bad value "fails the request on a
+        // path that already catches". It does not: getProvider() hands rpcUrl
+        // to `new JsonRpcProvider()`, which throws SYNCHRONOUSLY, from two call
+        // sites outside any try — and a stored `currentView: "wait-tx"` reaches
+        // one of them through restoreView(). So the row proves the claim
+        // against the real constructor rather than describing it.
+        alsoProven: (normalized, hostile) => {
+            // requireActual: bootPopup() mocks this module out for the boots
+            // above, and a mocked getProvider() would prove nothing at all
+            // about the constructor this row is a claim about.
+            const { getProvider } = jest.requireActual(
+                "../src/shared/balances",
+            );
+            expect(() => getProvider(hostile, "mainnet")).toThrow();
+            const provider = getProvider(normalized, "mainnet");
+            expect(provider).toBeTruthy();
+            provider.destroy();
+        },
+    },
+    {
+        field: "blockscoutUrl",
+        kind: KIND.SCALAR,
+        hostile: [42, true, { a: 1 }],
+        floorOnly: [[], "", null],
+        holds: (v) => isText(v) && v !== "",
+    },
+    {
+        field: "activeAddress",
+        kind: KIND.SCALAR,
+        hostile: [42, true, { a: 1 }],
+        floorOnly: [[ADDRESS], ""],
+        holds: isTextOrNull,
+    },
+    {
+        field: "selectedToken",
+        kind: KIND.SCALAR,
+        hostile: [42, true, { a: 1 }],
+        floorOnly: [[TOKEN_ADDRESS], ""],
+        holds: isTextOrNull,
+    },
+    {
+        field: "selectedWallet",
+        kind: KIND.SCALAR,
+        // The prototype members are the whole point: `wallets["map"]` is
+        // TRUTHY, so hasValidAddress()'s `&&` does not short-circuit and
+        // `.addresses[…]` throws. A stale INTEGER is the safe case.
+        hostile: ["map", "__proto__", { a: 1 }],
+        floorOnly: ["length", "constructor", "toString", "0", -1, 1.5, true],
+        holds: isIndexOrNull,
+        // SCALAR, and swept anyway: the restore path is precisely why this
+        // field gained a floor, so the sweep is the regression guard on it.
+        alsoSweep: true,
+        routes: true,
+        // A stale INTEGER index, which reaches the restore path by a different
+        // route from the prototype members above — falsy or out of range
+        // rather than truthy — and has to keep being the safe case.
+        hostileRestore: [{ value: "length" }, { value: 5 }],
+    },
+    {
+        field: "selectedAddress",
+        kind: KIND.SCALAR,
+        hostile: ["map", "__proto__", { a: 1 }],
+        floorOnly: ["length", "constructor", "toString", "0", -1, 1.5, true],
+        holds: isIndexOrNull,
+        alsoSweep: true,
+        routes: true,
+        hostileRestore: [{ value: 5 }],
+    },
+    {
+        field: "currentView",
+        kind: KIND.LOOSE,
+        routes: true,
+        // Compared, and concatenated into the debug banner's textContent
+        // (src/popup/views/helpers.js) with no gate in front of it, which
+        // coerces. Nothing renders FROM it without RESTORABLE_VIEWS.has()
+        // first, and Set.has() answers false for any value.
+        hostile: [42, "no-such-view", { a: 1 }],
+        // `saved.currentView || null`: the falsy polarity is the popup landing
+        // on Home, which every boot in "booting onto Home" below also drives.
+        falsy: [""],
+    },
+    {
+        field: "viewData",
+        kind: KIND.LOOSE,
+        routes: true,
+        // The container is taken verbatim; what makes its ENTRIES safe is the
+        // per-branch guard in src/popup/viewRouter.js. The sweep drives the
+        // container shapes below onto every restorable view; hostileRestore
+        // adds the records that PASS a branch's gate and then hand its
+        // renderer something it dereferences, which is where the entries are
+        // actually decided.
+        hostile: [42, "notarecord", { a: 1 }, [1, 2]],
+        // `structuredClone(saved.viewData || {})`: the container is never falsy
+        // in state whatever was stored, so no `!state.viewData` branch exists to
+        // drive.
+        neverFalsy: true,
+        hostileRestore: [
+            // success-tx passes on `data.hash`, and renderSuccess() then calls
+            // toAddressHtml(d.to) -> addressTitle() -> address.toLowerCase().
+            { value: { hash: "0x1" }, views: ["success-tx"] },
+            { value: { hash: "0x1", to: 42 }, views: ["success-tx"] },
+            {
+                value: { hash: "0x1", to: ADDRESS, decoded: { details: 7 } },
+                views: ["success-tx"],
+            },
+            {
+                value: {
+                    hash: "0x1",
+                    to: ADDRESS,
+                    decoded: { details: [{ address: 42 }] },
+                },
+                views: ["success-tx"],
+            },
+            // error-tx passes on `data.message`, same dereference.
+            { value: { message: "boom" }, views: ["error-tx"] },
+            { value: { message: "boom", to: 42 }, views: ["error-tx"] },
+            // transaction passes on `data.tx`.
+            { value: { tx: { hash: "0x1" } }, views: ["transaction"] },
+            {
+                value: {
+                    tx: {
+                        hash: "0x1",
+                        from: ADDRESS,
+                        to: ADDRESS,
+                        contractAddress: 42,
+                    },
+                },
+                views: ["transaction"],
+            },
+            // confirm-tx passes on `data.pendingTx`.
+            { value: { pendingTx: { amount: "1" } }, views: ["confirm-tx"] },
+            {
+                value: {
+                    pendingTx: {
+                        token: 42,
+                        from: ADDRESS,
+                        to: ADDRESS,
+                        amount: "1",
+                    },
+                },
+                views: ["confirm-tx"],
+            },
+            // wait-tx passes on `pendingWait.hash`; restoreWait() has checked
+            // the fields below it since it was written, and this is the
+            // regression guard.
+            {
+                value: {
+                    pendingWait: {
+                        hash: "0x1",
+                        txInfo: { to: 42, amount: "1" },
+                    },
+                },
+                views: ["wait-tx"],
+            },
+            // A record that passes EVERY branch's gate at once, driven onto
+            // every restorable view: a branch a view does not read must stay
+            // one it does not read, and each renderer must survive the fields
+            // another branch left behind.
+            {
+                value: {
+                    hash: "0x1",
+                    message: "boom",
+                    tx: { hash: "0x1" },
+                    pendingTx: { amount: "1" },
+                    pendingWait: { hash: "0x1" },
+                },
+            },
+        ],
+    },
+    {
+        field: "lastBalanceRefresh",
+        kind: KIND.LOOSE,
+        // Arithmetic only: `now - (s.lastBalanceRefresh || 0)` compares false
+        // for a non-number and forces a refresh.
+        hostile: [true, "notatime", { a: 1 }],
+        // `|| 0` collapses every falsy stored value to 0, so 0 IS the whole
+        // falsy polarity of this field — and it is the DEFAULT_STATE default,
+        // the value a profile carries until its first refresh lands.
+        falsy: [0],
+    },
+    {
+        field: "tokenHolderCache",
+        kind: KIND.LOOSE,
+        // Nothing DEREFERENCES it structurally. It is read by the
+        // field-agnostic snapshotPersisted()/deepEqual() in
+        // src/shared/state.js, which are safe for any value, and otherwise
+        // only reset wholesale in src/shared/chainSwitchFields.js.
+        hostile: [42, "notarecord", [1, 2]],
+        // `structuredClone(saved.tokenHolderCache || {})`.
+        neverFalsy: true,
+    },
+    {
+        field: "theme",
+        kind: KIND.LOOSE,
+        // Compared against "dark"/"light" in applyTheme() and otherwise falls
+        // to the system branch; assigned into an input .value, which coerces.
+        hostile: [42, "chartreuse", { a: 1 }],
+        // `saved.theme || "system"`.
+        neverFalsy: true,
+    },
+    {
+        field: "dustThresholdGwei",
+        kind: KIND.LOOSE,
+        hostile: ["notanumber", true, { a: 1 }],
+        // Survives verbatim, so the falsy slot is also wrong-typed: "" reaches
+        // filterTransactions() as a comparand and a settings input .value.
+        falsy: [""],
+    },
+    ...[
+        "rememberSiteChoice",
+        "showZeroBalanceTokens",
+        "hideSpoofedSymbols",
+        "hideLowHolderTokens",
+        "hideFraudContracts",
+        "hideDustTransactions",
+        "utcTimestamps",
+        "debugMode",
+    ].map((field) => ({
+        field,
+        kind: KIND.LOOSE,
+        // A flag: only ever tested for truthiness, and written back verbatim.
+        hostile: [42, "notabool", { a: 1 }],
+        // Both answers to that truthiness test have to be driven, and 0 is a
+        // value src/ never writes for a flag. For utcTimestamps and debugMode
+        // the falsy answer is also the DEFAULT_STATE default.
+        falsy: [0],
+    })),
+];
+
+function siteMapHolds(v) {
+    return (
+        isRecord(v) &&
+        Object.getPrototypeOf(v) === Object.prototype &&
+        !Object.prototype.hasOwnProperty.call(v, "__proto__") &&
+        Object.keys(v).every((key) => everyEntry(v[key], isText))
+    );
+}
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+// -------------------------------------------------------------- exhaustive
+
+describe("the contract covers the record", () => {
+    test("every persisted field has exactly one row, and no row invents one", () => {
+        const rows = CONTRACT.map((row) => row.field);
+
+        expect([...rows].sort()).toEqual([...PERSISTED_FIELDS].sort());
+    });
+
+    test("every row declares a kind this file knows how to prove", () => {
+        const kinds = Object.values(KIND);
+        for (const row of CONTRACT) {
+            expect(kinds).toContain(row.kind);
+            expect(row.hostile.length).toBeGreaterThan(0);
+        }
+    });
+});
+
+// ------------------------------------------------------------- the floors
+
+function profileWith(field, value) {
+    return unversionedValidProfile({ [field]: value });
+}
+
+describe("the floor each row claims", () => {
+    // The falsy slot is deliberately NOT in here. `saved.x || default` is a
+    // floor on falsy values and on nothing else, so a falsy value is the one
+    // thing a LOOSE field need not carry through verbatim; what it has to carry
+    // through is being falsy, which "both polarities" below asserts.
+    for (const row of CONTRACT) {
+        const values = [...row.hostile, ...(row.floorOnly || [])];
+
+        if (row.kind === KIND.REFUSED) {
+            test(`${row.field}: the gate refuses it`, () => {
+                for (const value of values) {
+                    expect(
+                        typeof stateProblem(profileWith(row.field, value)),
+                    ).toBe("string");
+                }
+            });
+            continue;
+        }
+
+        test(`${row.field}: ${row.kind}`, () => {
+            for (const value of values) {
+                const out = normalizePersisted(profileWith(row.field, value));
+                if (row.kind === KIND.LOOSE) {
+                    // The claim IS that there is no floor. A field that grows
+                    // one has to move to another kind rather than keep a row
+                    // saying its readers are what make it safe.
+                    continue;
+                }
+                expect({
+                    value: value,
+                    holds: row.holds(out[row.field]),
+                }).toEqual({ value: value, holds: true });
+            }
+        });
+
+        if (row.kind === KIND.LOOSE) {
+            test(`${row.field}: is genuinely unfloored`, () => {
+                // EVERY value, not some: a PARTIAL floor is still a floor, and
+                // a row that keeps saying LOOSE because one hostile value out
+                // of three still survives is exactly the stale claim this file
+                // exists to stop.
+                for (const value of values) {
+                    const out = normalizePersisted(
+                        profileWith(row.field, value),
+                    );
+                    expect({
+                        value: value,
+                        survived: JSON.stringify(out[row.field]),
+                    }).toEqual({
+                        value: value,
+                        survived: JSON.stringify(value),
+                    });
+                }
+            });
+        }
+    }
+});
+
+// --------------------------------------------- driving the real popup boot
+
+// A booted popup is healthy when nothing threw out of init() and something is
+// on screen. A throw out of restoreView() is neither: init() does not guard it,
+// so the rest of popup init never runs and the user gets a popup with no view,
+// no message and no control on it.
+async function bootHealth(profile) {
+    const env = await bootPopup(profile);
+    return {
+        errors: env.pageErrors,
+        blank: env.visibleViews().length === 0,
+    };
+}
+
+const HEALTHY = { errors: [], blank: false };
+
+// unversionedValidProfile() stores no currentView, so every boot in here lands
+// on Home. That is the cheap half of the proof; the restore path below is the
+// half that matters.
+// Both polarities of every swept field are driven, or the field is proven
+// unable to take one of them. This is the guard on the sweep itself: a hostile
+// set is all-truthy by construction, so without a falsy slot a dereference
+// behind `if (!state.x)` is never reached on the boot that corrupts x — the
+// same falsy-collapse blind spot the fields below were floored for.
+describe("both polarities of every swept field are driven", () => {
+    const FALSY_STORED = [0, "", false, null];
+    const floored = (field, value) =>
+        normalizePersisted(profileWith(field, value))[field];
+
+    for (const row of CONTRACT) {
+        if (!swept(row)) continue;
+
+        if (row.neverFalsy) {
+            test(`${row.field}: cannot be falsy in state at all`, () => {
+                for (const value of FALSY_STORED) {
+                    expect({
+                        stored: value,
+                        truthy: Boolean(floored(row.field, value)),
+                    }).toEqual({ stored: value, truthy: true });
+                }
+            });
+            continue;
+        }
+
+        test(`${row.field}: truthy and falsy`, () => {
+            // What the boots below actually drive, floored the way a renderer
+            // sees it — not what the row says it drives.
+            const driven = [
+                ...sweptValues(row),
+                ...(row.hostileRestore || []).map((entry) => entry.value),
+            ].map((value) => floored(row.field, value));
+
+            expect({
+                truthy: driven.some((value) => Boolean(value)),
+                falsy: driven.some((value) => !value),
+            }).toEqual({ truthy: true, falsy: true });
+        });
+    }
+});
+
+describe("a hostile value for one field, booting onto Home", () => {
+    for (const row of CONTRACT) {
+        for (const value of sweptValues(row)) {
+            test(`${row.field} = ${JSON.stringify(value)}`, async () => {
+                await expect(
+                    bootHealth(profileWith(row.field, value)),
+                ).resolves.toEqual(HEALTHY);
+            });
+        }
+    }
+});
+
+describe("a row's extra proof against the real reader", () => {
+    for (const row of CONTRACT) {
+        if (!row.alsoProven) continue;
+        test(row.field, () => {
+            for (const value of row.hostile) {
+                const out = normalizePersisted(profileWith(row.field, value));
+                row.alsoProven(out[row.field], value);
+            }
+        });
+    }
+});
+
+// ------------------------------------------------ driving the restore path
+
+// Everything above lands on Home. Home is not where this class of defect
+// lives: all three of the false claims this file replaced were falsified by a
+// RESTORE, through the unguarded restoreView() in src/popup/index.js. So a
+// swept row's hostile values are driven onto EVERY restorable view, one boot
+// each.
+//
+// This is what makes a LOOSE row falsifiable. A field that gains a structural
+// dereference on any restorable view — `state.theme.toLowerCase()` in a view's
+// show(), say — turns the row red here, instead of waiting for a reviewer to
+// re-derive the claim by hand.
+
+// restoreWait() resumes from this, so it has to be a finite number and recent
+// enough that the resumed deadline has not already passed — a wait that has
+// outlived its deadline resolves on the first poll instead of staying on
+// screen. Read once at module load, so every boot in one run shares it.
+const BROADCAST_TIME = Date.now();
+
+// A viewData well formed for every restorable branch at once, so the only
+// thing a swept boot can fail on is the field the row corrupts. "the base
+// profile the sweep corrupts" below proves this really does render each view
+// rather than falling back — without that, a sweep could pass by never
+// reaching a renderer at all.
+const WELL_FORMED_DATA = {
+    hash: "0x1",
+    message: "boom",
+    to: ADDRESS,
+    decoded: { details: [{ address: TOKEN_ADDRESS }] },
+    tx: { hash: "0x1", from: ADDRESS, to: ADDRESS, contractAddress: null },
+    pendingTx: {
+        token: "ETH",
+        from: ADDRESS,
+        to: ADDRESS,
+        amount: "1",
+        balance: "2",
+    },
+    pendingWait: {
+        hash: "0x1",
+        txInfo: { to: ADDRESS, amount: "1" },
+        broadcastTime: BROADCAST_TIME,
+    },
+};
+
+function restoringOnto(view, extra) {
+    return unversionedValidProfile({
+        currentView: view,
+        selectedWallet: 0,
+        selectedAddress: 0,
+        selectedToken: TOKEN_ADDRESS,
+        viewStack: ["main"],
+        viewData: WELL_FORMED_DATA,
+        ...extra,
+    });
+}
+
+// A boot that RESTORED is healthy and landed on the view it stored, rather
+// than falling back to Home — which a healthy boot also does, and which would
+// let a sweep pass by never running the renderer it is aimed at.
+async function restoredHealth(profile, view) {
+    const env = await bootPopup(profile);
+    return {
+        errors: env.pageErrors,
+        restored: env.visibleViews().includes(view),
+    };
+}
+
+const RESTORED = { errors: [], restored: true };
+
+describe("the base profile the sweep corrupts", () => {
+    for (const view of RESTORABLE_VIEWS) {
+        test(`renders ${view} rather than falling back`, async () => {
+            await expect(
+                restoredHealth(restoringOnto(view), view),
+            ).resolves.toEqual(RESTORED);
+        });
+    }
+});
+
+// A field the ROUTER itself reads — the two it gates on and the two
+// hasValidAddress() indexes with. A hostile value in one of these legitimately
+// changes which view renders, so each gets its own boot per view and is held
+// only to "healthy", not to "restored onto the view it stored".
+const routes = (row) => Boolean(row.routes);
+
+// Every routing row × every hostile value × every restorable view. Profiles
+// are deduplicated because a hostile `currentView` REPLACES the view being
+// restored onto, which would otherwise be the same boot eleven times.
+describe("a hostile routing value restoring onto", () => {
+    for (const row of CONTRACT) {
+        if (!swept(row) || !routes(row)) continue;
+        const seen = new Set();
+        for (const value of sweptValues(row)) {
+            for (const view of RESTORABLE_VIEWS) {
+                const profile = restoringOnto(view, { [row.field]: value });
+                const key = JSON.stringify(profile);
+                if (seen.has(key)) continue;
+                seen.add(key);
+                test(`${view}: ${row.field} = ${JSON.stringify(
+                    value,
+                )}`, async () => {
+                    await expect(bootHealth(profile)).resolves.toEqual(HEALTHY);
+                });
+            }
+        }
+    }
+});
+
+// Every OTHER swept field, corrupted at once, one boot per view per hostile
+// slot: twelve fields on one boot rather than twelve boots. A field is only in
+// here because it is not one the router reads — and that is ASSERTED, not
+// argued, because the boot has to land on `view`. A field that does move the
+// routing turns this red and has to declare `routes` and take the individual
+// sweep above.
+//
+// Combining hides one thing, and the last slot is what stops it. A hostile
+// value is wrong-typed and therefore TRUTHY, so on a boot where every swept
+// field is hostile, no `if (!state.x)` branch is entered — and a dereference
+// inside such a branch would go unseen however loudly it throws. The last slot
+// is the falsy one: every swept field that CAN be falsy is falsy on it, which
+// is also the state an ordinary install boots in for three of them, while the
+// fields that cannot be falsy stay hostile-truthy. That makes it a MIX, and a
+// deliberate one — the interaction between a falsy flag and a still-hostile
+// theme is a shape a stored record really produces.
+//
+// The verdict is the combined boot, always. When it goes red the same view is
+// re-booted one field at a time, so the failure NAMES a culprit instead of
+// leaving a reader to bisect twelve fields — but that loop only decorates the
+// message. It cannot clear the failure. A dereference that needs two corrupted
+// fields at once is reproduced by neither field alone, and a version of this
+// file that asserted on the named list reported exactly that case green while
+// watching the popup die.
+const UNROUTED = CONTRACT.filter((row) => swept(row) && !routes(row));
+const HOSTILE_SLOTS = Math.max(
+    ...UNROUTED.map((row) => sweptValues(row).length),
+);
+
+function unroutedValues(slot) {
+    const fields = {};
+    for (const row of UNROUTED) {
+        const values = sweptValues(row);
+        fields[row.field] = values[slot % values.length];
+    }
+    return fields;
+}
+
+describe("every field the router does not read, corrupted at once, onto", () => {
+    for (const view of RESTORABLE_VIEWS) {
+        for (let slot = 0; slot < HOSTILE_SLOTS; slot++) {
+            test(`${view}: hostile value ${slot + 1} in all ${
+                UNROUTED.length
+            } of them`, async () => {
+                const fields = unroutedValues(slot);
+                const together = await restoredHealth(
+                    restoringOnto(view, fields),
+                    view,
+                );
+
+                // The per-field re-boot only DECORATES the message. The
+                // verdict is `together`, unconditionally: a dereference that
+                // needs two corrupted fields at once is reproduced by NEITHER
+                // field alone, so an assertion on the named list would report
+                // an observed dead popup as green.
+                const named = [];
+                if (together.errors.length > 0 || !together.restored) {
+                    for (const row of UNROUTED) {
+                        const one = await restoredHealth(
+                            restoringOnto(view, {
+                                [row.field]: fields[row.field],
+                            }),
+                            view,
+                        );
+                        if (one.errors.length === 0 && one.restored) continue;
+                        named.push(
+                            `${row.field}=${JSON.stringify(
+                                fields[row.field],
+                            )}: ` +
+                                (one.errors.join("; ") || `fell off ${view}`),
+                        );
+                    }
+                    if (named.length === 0) {
+                        named.push(
+                            "no single field reproduces it; it takes two or " +
+                                `more of ${JSON.stringify(fields)}`,
+                        );
+                    }
+                }
+
+                expect({
+                    view: view,
+                    together: together,
+                    fields: named,
+                }).toEqual({ view: view, together: RESTORED, fields: [] });
+            });
+        }
+    }
+});
+
+// The values that only mean something on the restore path: a viewData that
+// PASSES a branch's gate and then hands its renderer something dereferenced,
+// and the index values whose route through hasValidAddress() differs from the
+// row's own hostile set.
+describe("a restore-only hostile value onto", () => {
+    for (const row of CONTRACT) {
+        for (const entry of row.hostileRestore || []) {
+            for (const view of entry.views || RESTORABLE_VIEWS) {
+                test(`${view}: ${row.field} = ${JSON.stringify(
+                    entry.value,
+                )}`, async () => {
+                    await expect(
+                        bootHealth(
+                            restoringOnto(view, { [row.field]: entry.value }),
+                        ),
+                    ).resolves.toEqual(HEALTHY);
+                });
+            }
+        }
+    }
+});

tests/popupElementIds.test.js

@@ -35,6 +35,11 @@ const POPUP_HTML_PATH = path.join(POPUP_DIR, "index.html");
 const RUNTIME_CREATED_IDS = new Set([
     // Created by updateDebugBanner() in src/popup/views/helpers.js.
     "debug-banner",
+    // Created by showSaveFailureBanner() in the same file, on the first save
+    // that fails. Absent from the markup on purpose: a popup where nothing has
+    // failed must not have to carry an empty banner
+    // (https://git.eeqj.de/sneak/AutistMask/issues/362).
+    "save-failure-banner",
 ]);
 
 // Every id lookup the popup performs with a literal argument, as

tests/stateRecovery.test.js

@@ -13,61 +13,26 @@
 // calls, is exactly the defect: what has to be true is that BOOTING the popup
 // on a bad blob lands on it.
 //
-// The DOM stub is built FROM src/popup/index.html — every id in the markup,
-// with the classes the markup gives it — so "which views are visible" is
-// answered against the real element set, and a recovery screen with no markup
-// behind it cannot pass.
+// The boot harness and its DOM stub — built FROM src/popup/index.html, so
+// "which views are visible" is answered against the real element set — live in
+// tests/support/popupBoot.js, since tests/persistedEntryFloors.test.js needs
+// the same boot.
 //
 // The fourth case is the upgrade one, and it is the case that must NOT reach
 // the recovery screen: every install in the field has a valid profile with no
 // version field, and showing those users a wipe prompt would be a worse defect
 // than the one being fixed. It is migrated in place and keeps working.
 
-const fs = require("fs");
-const path = require("path");
-
-const { makeStorageStub } = require("./support/storageStub");
-
-const POPUP_HTML = fs.readFileSync(
-    path.join(__dirname, "..", "src", "popup", "index.html"),
-    "utf8",
-);
-
-// Fixed address, never used for anything but these tests.
-const ADDRESS = "0x66133E8ea0f5D1d612D2502a968757D1048c214a";
-// A fixed ERC-20 contract address, same rule.
-const TOKEN_ADDRESS = "0xAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    ADDRESS,
+    TOKEN_ADDRESS,
+} = require("./support/popupBoot");
 
 // ------------------------------------------------------------- fixtures
 
-// A profile in the shape every install in the field has it: complete, valid,
-// and carrying no version field, because no build ever wrote one.
-function unversionedValidProfile() {
-    return {
-        hasWallet: true,
-        wallets: [
-            {
-                type: "hd",
-                name: "Wallet 1",
-                xpub: "xpub-wallet-1",
-                encryptedSecret: "encrypted-secret-1",
-                nextIndex: 1,
-                addresses: [
-                    { address: ADDRESS, balance: "1.5", tokenBalances: [] },
-                ],
-            },
-        ],
-        activeAddress: ADDRESS,
-        networkId: "mainnet",
-        rpcUrl: "https://ethereum-rpc.publicnode.com",
-        blockscoutUrl: "https://eth.blockscout.com/api/v2",
-        allowedSites: { [ADDRESS]: ["dapp.example"] },
-        deniedSites: {},
-        trackedTokens: [],
-        theme: "system",
-    };
-}
-
 // The three blobs from the issue, each with the error it produced.
 const CORRUPT_BLOBS = [
     {
@@ -103,235 +68,7 @@ const CORRUPT_BLOBS = [
     },
 ];
 
-// ------------------------------------------------------------- DOM stub
-
-function makeElement(id, className) {
-    const classes = new Set(
-        (className || "").split(/\s+/).filter((name) => name !== ""),
-    );
-    const el = {
-        id,
-        tagName: "DIV",
-        textContent: "",
-        value: "",
-        innerHTML: "",
-        href: "",
-        download: "",
-        disabled: false,
-        style: {},
-        dataset: {},
-        listeners: {},
-        clicked: 0,
-        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);
-        },
-        removeEventListener: () => {},
-        appendChild: () => {},
-        remove: () => {},
-        focus: () => {},
-        select: () => {},
-        setAttribute: (name, value) => {
-            el[name] = value;
-        },
-        querySelector: () => null,
-        querySelectorAll: () => [],
-        click: () => {
-            el.clicked += 1;
-        },
-    };
-    return el;
-}
-
-// Every id in the markup, with the classes the markup gives it. A view the
-// popup is supposed to reveal has to exist here, which means it has to exist
-// in src/popup/index.html.
-function idsFromHtml(html) {
-    const out = new Map();
-    const tags = html.match(/<[a-zA-Z][^>]*>/g) || [];
-    for (const tag of tags) {
-        const id = /\bid="([^"]+)"/.exec(tag);
-        if (!id) continue;
-        const cls = /\bclass="([^"]*)"/.exec(tag);
-        out.set(id[1], cls ? cls[1] : "");
-    }
-    return out;
-}
-
-function makeDocument(html) {
-    const authored = idsFromHtml(html);
-    const els = new Map();
-    for (const [id, className] of authored) {
-        els.set(id, makeElement(id, className));
-    }
-    const created = [];
-    const doc = {
-        listeners: {},
-        getElementById(id) {
-            // Created on demand by updateDebugBanner(); 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(tag) {
-            const el = makeElement("created-" + tag, "");
-            el.tagName = String(tag).toUpperCase();
-            created.push(el);
-            return el;
-        },
-        addEventListener(name, fn) {
-            doc.listeners[name] = doc.listeners[name] || [];
-            doc.listeners[name].push(fn);
-        },
-        querySelectorAll: () => [],
-        documentElement: makeElement("html", ""),
-        body: {
-            prepend: () => {},
-            appendChild: () => {},
-            removeChild: () => {},
-        },
-        elements: els,
-        authoredIds: authored,
-        created,
-    };
-    return doc;
-}
-
-// ------------------------------------------------------------- harness
-
-// Boot the real popup entry point over `stored`, exactly as the browser does:
-// storage already holds the record, the page loads, DOMContentLoaded fires.
-async function bootPopup(stored) {
-    jest.resetModules();
-
-    // The two modules that reach the network. Neither is on the path under
-    // test; both would make this suite hit the internet.
-    jest.doMock("../src/shared/prices", () => ({
-        prices: {},
-        refreshPrices: jest.fn(async () => {}),
-        clearPrices: jest.fn(),
-        getPrice: () => null,
-        formatUsd: () => "",
-        formatAddressTotal: () => "",
-        getAddressValue: () => ({ usd: null, partial: false }),
-        getWalletValue: () => ({ usd: null, partial: false }),
-        getTotalValue: () => ({ usd: null, partial: false }),
-    }));
-    jest.doMock("../src/shared/balances", () => ({
-        fetchTokenBalances: jest.fn(async () => []),
-        refreshBalances: jest.fn(async () => {}),
-        lookupTokenInfo: jest.fn(async () => null),
-        getProvider: () => ({}),
-        scanForAddresses: jest.fn(async () => []),
-    }));
-    jest.doMock("../src/shared/transactions", () => ({
-        fetchRecentTransactions: jest.fn(async () => []),
-        filterTransactions: () => [],
-    }));
-
-    const storage = makeStorageStub(
-        stored === undefined ? {} : { autistmask: stored },
-    );
-    const document = makeDocument(POPUP_HTML);
-    const reloads = [];
-
-    globalThis.chrome = {
-        storage: { local: storage.local },
-        runtime: {
-            sendMessage: jest.fn(async () => ({})),
-            getURL: (p) => "chrome-extension://autistmask/" + p,
-            onMessage: { addListener: () => {} },
-        },
-    };
-    globalThis.document = document;
-    globalThis.window = {
-        location: {
-            search: "",
-            href: "chrome-extension://autistmask/src/popup/index.html",
-            reload: () => reloads.push(Date.now()),
-        },
-        matchMedia: () => ({
-            matches: false,
-            addEventListener: () => {},
-            removeEventListener: () => {},
-        }),
-        addEventListener: () => {},
-    };
-    // The 10s refresh loop init() starts would outlive the test.
-    const realSetInterval = globalThis.setInterval;
-    globalThis.setInterval = () => 0;
-
-    require("../src/popup/index");
-
-    const booted = [];
-    for (const fn of document.listeners.DOMContentLoaded || []) {
-        booted.push(fn());
-    }
-
-    // What the browser console would have shown. A throw out of init() is the
-    // blank popup this issue is about, so it is captured rather than thrown:
-    // the assertion that matters is what ended up on screen.
-    const pageErrors = [];
-    for (const p of booted) {
-        try {
-            await p;
-        } catch (e) {
-            pageErrors.push(String((e && e.message) || e));
-        }
-    }
-    await settle();
-
-    globalThis.setInterval = realSetInterval;
-
-    return {
-        storage,
-        document,
-        pageErrors,
-        reloaded: () => reloads.length,
-        node: (id) => document.getElementById(id),
-        text: (id) => document.getElementById(id).textContent,
-        value: (id) => document.getElementById(id).value,
-        hidden: (id) =>
-            document.getElementById(id).classList.contains("hidden"),
-        click: async (id) => {
-            const el = document.getElementById(id);
-            const fns = el.listeners.click || [];
-            for (const fn of fns) await fn();
-            await settle();
-        },
-        // The view ids whose section is not hidden, as the audit measured them.
-        visibleViews: () => {
-            const out = [];
-            for (const [id, el] of document.elements) {
-                if (!id.startsWith("view-")) continue;
-                if (!el.classList.contains("hidden")) out.push(id.slice(5));
-            }
-            return out;
-        },
-    };
-}
-
-async function settle() {
-    for (let i = 0; i < 50; i++) await Promise.resolve();
-}
-
-afterEach(() => {
-    delete globalThis.chrome;
-    delete globalThis.document;
-    delete globalThis.window;
-});
+afterEach(cleanupPopup);
 
 // --------------------------------------------------------------- tests
 

tests/support/popupBoot.js

@@ -0,0 +1,347 @@
+// Boot the REAL popup entry point over a stored record, exactly as the browser
+// does: storage already holds the record, the page loads, DOMContentLoaded
+// fires.
+//
+// Written for https://git.eeqj.de/sneak/AutistMask/issues/311 inside
+// tests/stateRecovery.test.js and lifted here unchanged in substance when
+// https://git.eeqj.de/sneak/AutistMask/issues/362 needed the same boot for a
+// second field. Assertions about a corrupt stored profile have to be made
+// through the entry point rather than against a view module: a screen that
+// renders perfectly when something calls it, and that nothing calls, IS the
+// defect.
+//
+// The DOM stub is built FROM src/popup/index.html — every id in the markup,
+// with the classes the markup gives it — so "which views are visible" is
+// answered against the real element set, and a screen with no markup behind it
+// cannot pass.
+
+const fs = require("fs");
+const path = require("path");
+
+const { makeStorageStub } = require("./storageStub");
+
+const POPUP_HTML = fs.readFileSync(
+    path.join(__dirname, "..", "..", "src", "popup", "index.html"),
+    "utf8",
+);
+
+// Fixed addresses, never used for anything but these tests.
+const ADDRESS = "0x66133E8ea0f5D1d612D2502a968757D1048c214a";
+const TOKEN_ADDRESS = "0xAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
+
+// A profile in the shape every install in the field has it: complete, valid,
+// and carrying no version field, because no build ever wrote one. The starting
+// point for "and now corrupt exactly one field of it".
+function unversionedValidProfile(extra) {
+    return {
+        hasWallet: true,
+        wallets: [
+            {
+                type: "hd",
+                name: "Wallet 1",
+                xpub: "xpub-wallet-1",
+                encryptedSecret: "encrypted-secret-1",
+                nextIndex: 1,
+                addresses: [
+                    { address: ADDRESS, balance: "1.5", tokenBalances: [] },
+                ],
+            },
+        ],
+        activeAddress: ADDRESS,
+        networkId: "mainnet",
+        rpcUrl: "https://ethereum-rpc.publicnode.com",
+        blockscoutUrl: "https://eth.blockscout.com/api/v2",
+        allowedSites: { [ADDRESS]: ["dapp.example"] },
+        deniedSites: {},
+        trackedTokens: [],
+        theme: "system",
+        ...(extra || {}),
+    };
+}
+
+function makeElement(id, className) {
+    const classes = new Set(
+        (className || "").split(/\s+/).filter((name) => name !== ""),
+    );
+    const el = {
+        id,
+        tagName: "DIV",
+        textContent: "",
+        value: "",
+        innerHTML: "",
+        href: "",
+        download: "",
+        disabled: false,
+        style: {},
+        dataset: {},
+        listeners: {},
+        clicked: 0,
+        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);
+        },
+        removeEventListener: () => {},
+        appendChild: () => {},
+        remove: () => {},
+        focus: () => {},
+        select: () => {},
+        setAttribute: (name, value) => {
+            el[name] = value;
+        },
+        querySelector: () => null,
+        querySelectorAll: () => [],
+        // The Receive view draws its QR onto #receive-qr through the qrcode
+        // package, which calls getContext("2d") and then createImageData/
+        // putImageData on the result. Without this the render throws from
+        // inside a promise the view does not await, which takes the whole node
+        // process down rather than failing a test — so a suite that boots onto
+        // Receive could not report anything.
+        getContext: () => ({
+            createImageData: (w, h) => ({
+                width: w,
+                height: h,
+                data: new Uint8ClampedArray(w * h * 4),
+            }),
+            putImageData: () => {},
+            clearRect: () => {},
+        }),
+        click: () => {
+            el.clicked += 1;
+        },
+    };
+    // src/ reaches parentElement only to hide or unhide the wrapper a field
+    // sits in (txStatus.js renderSuccess(), transactionDetail.js render()).
+    // The stub is flat — it is built from the ids in the markup, not from its
+    // tree — so each element gets a wrapper of its own, made on demand so this
+    // does not recurse. It is never registered by id, so nothing can mistake
+    // it for a view. Without it, success-tx and transaction throw on the first
+    // line that touches a wrapper and cannot be booted onto at all.
+    let parent = null;
+    Object.defineProperty(el, "parentElement", {
+        get() {
+            if (!parent) parent = makeElement(id + "-parent", "");
+            return parent;
+        },
+    });
+    return el;
+}
+
+// Every id in the markup, with the classes the markup gives it. A view the
+// popup is supposed to reveal has to exist here, which means it has to exist
+// in src/popup/index.html.
+function idsFromHtml(html) {
+    const out = new Map();
+    const tags = html.match(/<[a-zA-Z][^>]*>/g) || [];
+    for (const tag of tags) {
+        const id = /\bid="([^"]+)"/.exec(tag);
+        if (!id) continue;
+        const cls = /\bclass="([^"]*)"/.exec(tag);
+        out.set(id[1], cls ? cls[1] : "");
+    }
+    return out;
+}
+
+// Ids the popup creates at runtime rather than authoring in the markup, and
+// that must therefore read as ABSENT until something creates them. Answering
+// with a fresh element instead would make "is the banner up?" always true.
+const RUNTIME_IDS = new Set(["debug-banner", "save-failure-banner"]);
+
+function makeDocument(html) {
+    const authored = idsFromHtml(html);
+    const els = new Map();
+    for (const [id, className] of authored) {
+        els.set(id, makeElement(id, className));
+    }
+    const created = [];
+    const prepended = [];
+    const doc = {
+        listeners: {},
+        getElementById(id) {
+            if (RUNTIME_IDS.has(id) && !els.has(id)) return null;
+            if (!els.has(id)) els.set(id, makeElement(id, ""));
+            return els.get(id);
+        },
+        createElement(tag) {
+            const el = makeElement("created-" + tag, "");
+            el.tagName = String(tag).toUpperCase();
+            created.push(el);
+            return el;
+        },
+        addEventListener(name, fn) {
+            doc.listeners[name] = doc.listeners[name] || [];
+            doc.listeners[name].push(fn);
+        },
+        querySelectorAll: () => [],
+        documentElement: makeElement("html", ""),
+        body: {
+            // Recorded, and registered under its id: a banner the popup
+            // prepends is on the page from then on, and a test asking for it
+            // by id has to find it.
+            prepend: (el) => {
+                prepended.push(el);
+                if (el && el.id) els.set(el.id, el);
+            },
+            appendChild: () => {},
+            removeChild: () => {},
+        },
+        elements: els,
+        authoredIds: authored,
+        created,
+        prepended,
+    };
+    return doc;
+}
+
+async function settle() {
+    for (let i = 0; i < 50; i++) await Promise.resolve();
+}
+
+/**
+ * Boot the popup over `stored`.
+ *
+ * @param {*} stored the record storage holds, or undefined for a first run.
+ * @param {object} [options]
+ * @param {object} [options.storage] a storage stub from makeStorageStub(), for
+ *     a test that needs to make writes fail or to watch the round trips.
+ * @returns {Promise<object>} handles onto the booted page.
+ */
+async function bootPopup(stored, options) {
+    jest.resetModules();
+
+    // The three modules that reach the network. None is on the path under
+    // test; all would make the suite hit the internet.
+    jest.doMock("../../src/shared/prices", () => ({
+        prices: {},
+        refreshPrices: jest.fn(async () => {}),
+        clearPrices: jest.fn(),
+        getPrice: () => null,
+        formatUsd: () => "",
+        formatAddressTotal: () => "",
+        getAddressValue: () => ({ usd: null, partial: false }),
+        getWalletValue: () => ({ usd: null, partial: false }),
+        getTotalValue: () => ({ usd: null, partial: false }),
+    }));
+    jest.doMock("../../src/shared/balances", () => ({
+        fetchTokenBalances: jest.fn(async () => []),
+        refreshBalances: jest.fn(async () => {}),
+        lookupTokenInfo: jest.fn(async () => null),
+        getProvider: () => ({}),
+        scanForAddresses: jest.fn(async () => []),
+    }));
+    jest.doMock("../../src/shared/transactions", () => ({
+        fetchRecentTransactions: jest.fn(async () => []),
+        filterTransactions: () => [],
+    }));
+
+    const storage =
+        (options && options.storage) ||
+        makeStorageStub(stored === undefined ? {} : { autistmask: stored });
+    const document = makeDocument(POPUP_HTML);
+    const reloads = [];
+
+    globalThis.chrome = {
+        storage: { local: storage.local },
+        runtime: {
+            sendMessage: jest.fn(async () => ({})),
+            getURL: (p) => "chrome-extension://autistmask/" + p,
+            onMessage: { addListener: () => {} },
+        },
+    };
+    globalThis.document = document;
+    globalThis.window = {
+        location: {
+            search: "",
+            href: "chrome-extension://autistmask/src/popup/index.html",
+            reload: () => reloads.push(Date.now()),
+        },
+        matchMedia: () => ({
+            matches: false,
+            addEventListener: () => {},
+            removeEventListener: () => {},
+        }),
+        addEventListener: () => {},
+    };
+    // The 10s refresh loop init() starts would outlive the test.
+    const realSetInterval = globalThis.setInterval;
+    globalThis.setInterval = () => 0;
+
+    require("../../src/popup/index");
+
+    const booted = [];
+    for (const fn of document.listeners.DOMContentLoaded || []) {
+        booted.push(fn());
+    }
+
+    // What the browser console would have shown. A throw out of init() is the
+    // blank popup issue 311 is about, so it is captured rather than thrown:
+    // the assertion that matters is what ended up on screen.
+    const pageErrors = [];
+    for (const p of booted) {
+        try {
+            await p;
+        } catch (e) {
+            pageErrors.push(String((e && e.message) || e));
+        }
+    }
+    await settle();
+
+    globalThis.setInterval = realSetInterval;
+
+    return {
+        storage,
+        document,
+        pageErrors,
+        reloaded: () => reloads.length,
+        node: (id) => document.getElementById(id),
+        text: (id) => {
+            const el = document.getElementById(id);
+            return el ? el.textContent : null;
+        },
+        value: (id) => document.getElementById(id).value,
+        hidden: (id) =>
+            document.getElementById(id).classList.contains("hidden"),
+        click: async (id) => {
+            const el = document.getElementById(id);
+            const fns = el.listeners.click || [];
+            for (const fn of fns) await fn();
+            await settle();
+        },
+        settle,
+        // The view ids whose section is not hidden, as the audit measured them.
+        visibleViews: () => {
+            const out = [];
+            for (const [id, el] of document.elements) {
+                if (!id.startsWith("view-")) continue;
+                if (!el.classList.contains("hidden")) out.push(id.slice(5));
+            }
+            return out;
+        },
+    };
+}
+
+function cleanupPopup() {
+    delete globalThis.chrome;
+    delete globalThis.document;
+    delete globalThis.window;
+}
+
+module.exports = {
+    bootPopup,
+    cleanupPopup,
+    settle,
+    unversionedValidProfile,
+    ADDRESS,
+    TOKEN_ADDRESS,
+    POPUP_HTML,
+};

tests/uniswap.test.js

@@ -94,6 +94,69 @@ function encodeV4Swap(actions, params) {
     return coder.encode(["bytes", "bytes[]"], [actions, params]);
 }
 
+// V4 inner action IDs, as src/shared/uniswap.js names them.
+const V4_SWAP_EXACT_IN = 0x07;
+const V4_SWAP_EXACT_IN_SINGLE_ID = 0x06;
+const V4_SETTLE_ID = 0x0b;
+const V4_TAKE_ID = 0x0e;
+const ZERO_ADDR = "0x0000000000000000000000000000000000000000";
+
+// Helper: V4 SETTLE params — (address currency, uint256 maxAmount, bool payerIsUser)
+function encodeV4Settle(currency) {
+    return coder.encode(["address", "uint256", "bool"], [currency, 0n, true]);
+}
+
+// Helper: V4 TAKE params — (address currency, address recipient, uint256 amount)
+function encodeV4Take(currency) {
+    return coder.encode(
+        ["address", "address", "uint256"],
+        [currency, USER_ADDR, 0n],
+    );
+}
+
+// Helper: V4 ExactInputParams — (address currencyIn,
+//   tuple(address,uint24,int24,address,bytes)[] path,
+//   uint128 amountIn, uint128 amountOutMin)
+function encodeV4ExactIn(currencyIn, pathTokens, amountIn, amountOutMin) {
+    return coder.encode(
+        [
+            "tuple(address,tuple(address,uint24,int24,address,bytes)[],uint128,uint128)",
+        ],
+        [
+            [
+                currencyIn,
+                pathTokens.map((t) => [t, 3000, 60, ZERO_ADDR, "0x"]),
+                amountIn,
+                amountOutMin,
+            ],
+        ],
+    );
+}
+
+// Helper: V4 ExactInputSingleParams —
+//   (tuple(address,address,uint24,int24,address) poolKey, bool zeroForOne,
+//    uint128 amountIn, uint128 amountOutMin, bytes hookData)
+function encodeV4ExactInSingle(currency0, currency1, amountIn, amountOutMin) {
+    return coder.encode(
+        [
+            "tuple(tuple(address,address,uint24,int24,address),bool,uint128,uint128,bytes)",
+        ],
+        [
+            [
+                [currency0, currency1, 100, 1, ZERO_ADDR],
+                true, // zeroForOne: in = currency0, out = currency1
+                amountIn,
+                amountOutMin,
+                "0x",
+            ],
+        ],
+    );
+}
+
+function detail(result, label) {
+    return result.details.find((d) => d.label === label);
+}
+
 describe("uniswap decoder", () => {
     test("returns null for non-execute calldata", () => {
         expect(uniswap.decode("0x", ROUTER_ADDR)).toBeNull();
@@ -118,6 +181,18 @@ describe("uniswap decoder", () => {
         expect(tokenIn.value).toContain("USDT");
         expect(tokenIn.address.toLowerCase()).toBe(USDT_ADDR.toLowerCase());
 
+        // Genuine native ETH on the output side, on a real mainnet fixture:
+        // V4's TAKE names it as Currency.wrap(address(0)), which reaches the
+        // decoder as the explicit zero address and must still read as ETH.
+        const tokenOut = result.details.find((d) => d.label === "Token Out");
+        expect(tokenOut.value).toBe("ETH");
+        expect(result.details.find((d) => d.label === "Amount").value).toBe(
+            "Unlimited",
+        );
+        expect(
+            result.details.find((d) => d.label === "Min. received").value,
+        ).toBe("0.0002 ETH");
+
         const steps = result.details.find((d) => d.label === "Steps");
         expect(steps.value).toContain("Permit2 Permit");
         expect(steps.value).toContain("V4 Swap");
@@ -181,8 +256,7 @@ describe("uniswap decoder", () => {
         expect(tokenIn.value).toBe("ETH (native)");
 
         const amount = result.details.find((d) => d.label === "Amount");
-        expect(amount.value).toContain("1.0000");
-        expect(amount.value).toContain("ETH");
+        expect(amount.value).toBe("1.0000 ETH");
     });
 
     test("decodes UNWRAP_WETH as ETH output", () => {
@@ -338,6 +412,211 @@ describe("uniswap decoder", () => {
         expect(steps.value).toContain("V4 Swap");
     });
 
+    // https://git.eeqj.de/sneak/AutistMask/issues/364 — the input half.
+    //
+    // Fails against c9ebac8: `if (!inputAmount) inputAmount = s.amountIn`
+    // cannot tell the V3 hop's genuine 0n from "not yet set", so the V2 hop's
+    // 0.5 WETH overwrote it while Token In stayed pinned to the V3 hop's USDT.
+    // Observed there: Amount = "500000000000.0000 USDT".
+    test("a hop's zero amountIn is a real amount, not an opening for the next hop's figure", () => {
+        const data = buildExecute(
+            solidityPacked(["uint8", "uint8"], [0x00, 0x08]),
+            [
+                encodeV3SwapExactIn(USER_ADDR, 0n, 0n, [USDT_ADDR, WETH_ADDR]),
+                encodeV2SwapExactIn(
+                    USER_ADDR,
+                    500000000000000000n, // 0.5 WETH
+                    1000000n,
+                    [WETH_ADDR, USDC_ADDR],
+                ),
+            ],
+            9999999999n,
+        );
+
+        const result = uniswap.decode(data, ROUTER_ADDR);
+        expect(result).not.toBeNull();
+
+        // The amount and the token it is counted in come from the same hop.
+        expect(detail(result, "Token In").address.toLowerCase()).toBe(
+            USDT_ADDR.toLowerCase(),
+        );
+        expect(detail(result, "Amount").value).toBe("0.0000 USDT");
+        expect(detail(result, "Amount").value).not.toContain("500000000000");
+    });
+
+    // https://git.eeqj.de/sneak/AutistMask/issues/359 — the output half, in
+    // the shape the issue measured: a V4 step that states a minimum of zero
+    // and names no output currency.
+    //
+    // Fails against c9ebac8: `if (v4.amountOutMin) minOutput = ...` and the
+    // `else if` beside it both read 0n as absent, so neither the figure nor
+    // the token moved. Observed there: Token Out = "WETH (0xC02aaA39...)" and
+    // Min. received = "0.5000 WETH" — the V3 hop's guarantee shown for a
+    // transaction whose final leg guarantees nothing.
+    test("a V4 step with a zero amountOutMin states no minimum instead of keeping an earlier hop's", () => {
+        const data = buildExecute(
+            solidityPacked(["uint8", "uint8"], [0x00, 0x10]),
+            [
+                encodeV3SwapExactIn(USER_ADDR, 2000000n, 500000000000000000n, [
+                    USDT_ADDR,
+                    WETH_ADDR,
+                ]),
+                encodeV4Swap(new Uint8Array([V4_SWAP_EXACT_IN]), [
+                    encodeV4ExactIn(
+                        WETH_ADDR,
+                        [], // no path: this step names no output currency
+                        1000000000000000000n,
+                        0n, // no slippage floor at all
+                    ),
+                ]),
+            ],
+            9999999999n,
+        );
+
+        const result = uniswap.decode(data, ROUTER_ADDR);
+        expect(result).not.toBeNull();
+
+        expect(detail(result, "Token Out").value).toBe(
+            "Unknown (not named in the calldata)",
+        );
+        expect(detail(result, "Min. received").value).toBe(
+            "None (no minimum guaranteed)",
+        );
+        expect(detail(result, "Min. received").value).not.toContain("0.5000");
+    });
+
+    // The same zero floor, but with the final leg's output currency named:
+    // the figure must belong to the token beside it. Against c9ebac8 this
+    // rendered Token Out = USDC with Min. received = "500000000000.0000 USDC",
+    // the V3 hop's 0.5e18 WETH figure re-scaled to USDC's six decimals.
+    test("a zero minimum is stated against the token that supplied it", () => {
+        const data = buildExecute(
+            solidityPacked(["uint8", "uint8"], [0x00, 0x10]),
+            [
+                encodeV3SwapExactIn(USER_ADDR, 2000000n, 500000000000000000n, [
+                    USDT_ADDR,
+                    WETH_ADDR,
+                ]),
+                encodeV4Swap(
+                    new Uint8Array([
+                        V4_SETTLE_ID,
+                        V4_SWAP_EXACT_IN_SINGLE_ID,
+                        V4_TAKE_ID,
+                    ]),
+                    [
+                        encodeV4Settle(WETH_ADDR),
+                        encodeV4ExactInSingle(
+                            WETH_ADDR,
+                            USDC_ADDR,
+                            1000000000000000000n,
+                            0n,
+                        ),
+                        encodeV4Take(USDC_ADDR),
+                    ],
+                ),
+            ],
+            9999999999n,
+        );
+
+        const result = uniswap.decode(data, ROUTER_ADDR);
+        expect(result).not.toBeNull();
+
+        expect(detail(result, "Token Out").value).toContain("USDC");
+        expect(detail(result, "Min. received").value).toBe(
+            "None (no minimum guaranteed)",
+        );
+    });
+
+    // The other half of the same invariant: a final leg that names an output
+    // currency but no minimum leaves Min. received unstated. Against c9ebac8
+    // the V3 hop's figure stayed on screen beside the new token, rendering
+    // "500000000000.0000 USDC".
+    test("a final leg with no minimum drops the line rather than keeping an earlier hop's figure", () => {
+        const data = buildExecute(
+            solidityPacked(["uint8", "uint8"], [0x00, 0x10]),
+            [
+                encodeV3SwapExactIn(USER_ADDR, 2000000n, 500000000000000000n, [
+                    USDT_ADDR,
+                    WETH_ADDR,
+                ]),
+                encodeV4Swap(new Uint8Array([V4_SETTLE_ID, V4_TAKE_ID]), [
+                    encodeV4Settle(WETH_ADDR),
+                    encodeV4Take(USDC_ADDR),
+                ]),
+            ],
+            9999999999n,
+        );
+
+        const result = uniswap.decode(data, ROUTER_ADDR);
+        expect(result).not.toBeNull();
+
+        expect(detail(result, "Token Out").value).toContain("USDC");
+        expect(detail(result, "Min. received")).toBeUndefined();
+    });
+
+    // V4 spells "swap the whole open delta" as an amountIn of zero
+    // (v4-periphery ActionConstants.OPEN_DELTA = 0, applied by V4Router's
+    // _swapExactInputSingle / _swapExactInput). It is not a quantity, and
+    // printing "0.0000 WETH" for it would state the exact inverse of what the
+    // step does. Against c9ebac8 the Amount line was omitted entirely.
+    test("a V4 open-delta amountIn is named, not printed as zero", () => {
+        const data = buildExecute(
+            "0x10",
+            [
+                encodeV4Swap(
+                    new Uint8Array([
+                        V4_SETTLE_ID,
+                        V4_SWAP_EXACT_IN_SINGLE_ID,
+                        V4_TAKE_ID,
+                    ]),
+                    [
+                        encodeV4Settle(WETH_ADDR),
+                        encodeV4ExactInSingle(
+                            WETH_ADDR,
+                            USDC_ADDR,
+                            0n, // ActionConstants.OPEN_DELTA
+                            990000n,
+                        ),
+                        encodeV4Take(USDC_ADDR),
+                    ],
+                ),
+            ],
+            9999999999n,
+        );
+
+        const result = uniswap.decode(data, ROUTER_ADDR);
+        expect(result).not.toBeNull();
+
+        expect(detail(result, "Token In").value).toContain("WETH");
+        expect(detail(result, "Amount").value).toBe(
+            "All available (V4 open delta)",
+        );
+        expect(detail(result, "Min. received").value).toBe("0.9900 USDC");
+    });
+
+    // Pins what https://git.eeqj.de/sneak/AutistMask/pulls/356 changed without
+    // testing: a non-swap execute() carrying only PERMIT2_PERMIT names no
+    // output currency, so it says so and titles itself "Uniswap Swap" rather
+    // than inventing "Token Out: ETH".
+    test("a PERMIT2_PERMIT-only execute() invents no output token", () => {
+        const data = buildExecute(
+            "0x0a",
+            [encodePermit2(USDT_ADDR, 5000000n, ROUTER_ADDR)],
+            9999999999n,
+        );
+
+        const result = uniswap.decode(data, ROUTER_ADDR);
+        expect(result).not.toBeNull();
+        expect(result.name).toBe("Uniswap Swap");
+
+        expect(detail(result, "Token In").value).toContain("USDT");
+        expect(detail(result, "Token Out").value).toBe(
+            "Unknown (not named in the calldata)",
+        );
+        expect(detail(result, "Token Out").address).toBeUndefined();
+        expect(detail(result, "Min. received")).toBeUndefined();
+    });
+
     test("handles unknown tokens gracefully", () => {
         const fakeToken = "0x1111111111111111111111111111111111111111";
         const data = buildExecute(

tests/uniswapUndeterminedTokenIn.test.js

@@ -0,0 +1,182 @@
+// What the dApp approval screen says the input token of a swap is when the
+// calldata did not name one.
+//
+// Issue #357, the twin on the input side of
+// https://git.eeqj.de/sneak/AutistMask/issues/353: `tokenInfo(null)` answered
+// `{symbol: "ETH", decimals: 18}`, so a null `inputToken` rendered as
+// `Token In: ETH (native)` and titled the swap `Swap ETH -> X`. An
+// undetermined input was therefore asserted to the user as native ETH — the
+// same class as https://git.eeqj.de/sneak/AutistMask/issues/340 and
+// https://git.eeqj.de/sneak/AutistMask/issues/306, naming the wrong asset
+// rather than merely mis-scaling it.
+//
+// The determination this file pins is the one #353 established, checked here
+// on the input side: null is NOT how native ETH arrives. v4-core declares
+// `type Currency is address` and wraps `address(0)` for native ETH, and a
+// user-defined value type over `address` carries the plain `address` ABI
+// encoding, so a native-ETH currency reaches the decoder as the truthy string
+// "0x0000000000000000000000000000000000000000". WRAP_ETH sets that same
+// explicit zero address. Both halves are asserted below: the zero address
+// stays ETH, and null refuses.
+
+const { AbiCoder, Interface, solidityPacked } = require("ethers");
+const uniswap = require("../src/shared/uniswap");
+
+const ROUTER = "0x66a9893cc07d91d95644aedd05d03f95e1dba8af";
+const USER = "0x66133E8ea0f5D1d612D2502a968757D1048c214a";
+const ZERO = "0x0000000000000000000000000000000000000000";
+// Both in the bundled list: USDT at 6 decimals, USDC at 6.
+const USDT = "0xdAC17F958D2ee523a2206206994597C13D831ec7";
+const USDC = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48";
+
+// The same wording the output side refuses with — one screen, one vocabulary.
+const REFUSAL = "Unknown (not named in the calldata)";
+
+const ONE_ETH = 1000000000000000000n;
+
+const V4_SWAP_EXACT_IN = 0x07;
+const V4_SETTLE = 0x0b;
+const V4_TAKE = 0x0e;
+
+const coder = AbiCoder.defaultAbiCoder();
+const routerIface = new Interface([
+    "function execute(bytes commands, bytes[] inputs, uint256 deadline)",
+]);
+
+function execute(commands, inputs) {
+    return routerIface.encodeFunctionData("execute", [
+        commands,
+        inputs,
+        9999999999n,
+    ]);
+}
+
+function v4Input(actions, params) {
+    return coder.encode(
+        ["bytes", "bytes[]"],
+        [new Uint8Array(actions), params],
+    );
+}
+
+// IV4Router.ExactInputParams as the decoder reads it:
+// (Currency currencyIn, PathKey[] path, uint128 amountIn, uint128 minOut).
+function exactInParams(currencyIn, path, amountIn, amountOutMin) {
+    return coder.encode(
+        [
+            "tuple(address,tuple(address,uint24,int24,address,bytes)[],uint128,uint128)",
+        ],
+        [[currencyIn, path, amountIn, amountOutMin]],
+    );
+}
+
+// BALANCE_CHECK_ERC20 (command 0x0e): (address owner, address token,
+// uint256 minBalance). It names the output token and nothing about the input.
+function balanceCheck(token, minBalance) {
+    return coder.encode(
+        ["address", "address", "uint256"],
+        [USER, token, minBalance],
+    );
+}
+
+function detail(data, label) {
+    const decoded = uniswap.decode(data, ROUTER, {});
+    expect(decoded).not.toBeNull();
+    return decoded.details.find((d) => d.label === label);
+}
+
+describe("an execute() whose input currency never decoded", () => {
+    // A V4_SWAP whose sub-action params do not decode — an action encoding
+    // this decoder does not know — leaves every V4 token null. The
+    // BALANCE_CHECK still names the output, so the screen has a Min. received
+    // figure and a Token Out, and previously claimed the user was paying ETH
+    // for them.
+    const data = () =>
+        execute(solidityPacked(["uint8", "uint8"], [0x10, 0x0e]), [
+            coder.encode(["bytes", "bytes[]"], ["0x07", ["0x"]]),
+            balanceCheck(USDC, 2000000n),
+        ]);
+
+    test("says the input token is unknown instead of naming ETH", () => {
+        expect(detail(data(), "Token In").value).toBe(REFUSAL);
+    });
+
+    test("keeps a Token In line, so the screen never omits what is paid", () => {
+        const tokenIn = detail(data(), "Token In");
+        expect(tokenIn).toBeDefined();
+        // A refusal is not a token: nothing to link to an explorer.
+        expect(tokenIn.address).toBeUndefined();
+        expect(tokenIn.isToken).toBeUndefined();
+    });
+
+    test("does not name ETH in the swap title either", () => {
+        expect(uniswap.decode(data(), ROUTER, {}).name).toBe("Uniswap Swap");
+    });
+});
+
+describe("an execute() that names only an output token", () => {
+    // A lone BALANCE_CHECK_ERC20: nothing in it says what is being paid.
+    const data = () => execute("0x0e", [balanceCheck(USDT, 2000000n)]);
+
+    test("refuses the input rather than defaulting it to ETH", () => {
+        expect(detail(data(), "Token In").value).toBe(REFUSAL);
+        expect(uniswap.decode(data(), ROUTER, {}).name).toBe("Uniswap Swap");
+    });
+
+    test("still states the output it did establish", () => {
+        expect(detail(data(), "Token Out").value).toContain("USDT");
+        expect(detail(data(), "Min. received").value).toBe("2.0000 USDT");
+    });
+});
+
+describe("native ETH in, which V4 spells as the zero address", () => {
+    test("a Currency of address(0) decodes to a truthy address string", () => {
+        // The fact the whole determination rests on: an absent input currency
+        // and a native-ETH one are distinguishable here, because the ABI
+        // decoder never yields null for an address word.
+        const [currency] = coder.decode(
+            ["address", "uint256", "bool"],
+            coder.encode(["address", "uint256", "bool"], [ZERO, ONE_ETH, true]),
+        );
+        expect(currency).toBe(ZERO);
+        expect(Boolean(currency)).toBe(true);
+    });
+
+    test("a V4 SETTLE of the zero address is still ETH at 18 decimals", () => {
+        const data = execute("0x10", [
+            v4Input(
+                [V4_SETTLE, V4_SWAP_EXACT_IN, V4_TAKE],
+                [
+                    coder.encode(
+                        ["address", "uint256", "bool"],
+                        [ZERO, ONE_ETH, true],
+                    ),
+                    exactInParams(
+                        ZERO,
+                        [[USDT, 500, 10, ZERO, "0x"]],
+                        ONE_ETH,
+                        2000000n,
+                    ),
+                    coder.encode(
+                        ["address", "address", "uint256"],
+                        [USDT, USER, 0n],
+                    ),
+                ],
+            ),
+        ]);
+
+        expect(detail(data, "Token In").value).toBe("ETH (native)");
+        expect(detail(data, "Amount").value).toBe("1.0000 ETH");
+        expect(uniswap.decode(data, ROUTER, {}).name).toBe("Swap ETH → USDT");
+    });
+
+    test("WRAP_ETH is still ETH at 18 decimals", () => {
+        // WRAP_ETH names no currency of its own; the decoder supplies the
+        // explicit zero address for it, which is why it survives this change.
+        const data = execute("0x0b", [
+            coder.encode(["address", "uint256"], [ROUTER, ONE_ETH]),
+        ]);
+
+        expect(detail(data, "Token In").value).toBe("ETH (native)");
+        expect(detail(data, "Amount").value).toBe("1.0000 ETH");
+    });
+});

tests/unknownScaleDisplay.test.js

@@ -0,0 +1,185 @@
+// What the screens that READ a stored token balance do with a holding whose
+// scale nothing knows.
+//
+// https://git.eeqj.de/sneak/AutistMask/issues/349 stopped `fetchTokenBalances()`
+// fabricating a scale of 18, so a row it cannot state a quantity for is now
+// stored with `balance: null`. Every reader of that field therefore has two
+// distinct inputs where it used to have one, and the property that has to hold
+// at each of them is the same one this codebase keeps losing:
+//
+//     null (unknown) and 0 (genuinely zero) must produce DIFFERENT output.
+//
+// Losing it is what https://git.eeqj.de/sneak/AutistMask/issues/246,
+// https://git.eeqj.de/sneak/AutistMask/issues/306,
+// https://git.eeqj.de/sneak/AutistMask/issues/322,
+// https://git.eeqj.de/sneak/AutistMask/issues/359 and
+// https://git.eeqj.de/sneak/AutistMask/issues/364 each were. So every case
+// below asserts the pair, not just that the null branch does something
+// reasonable: an assertion on the null alone still passes on a build that
+// renders both as zero, which is precisely the build being guarded against.
+//
+// The writer half — that the fetcher stores null rather than 18 — is in
+// tests/fabricatedDecimals.test.js, and the Send and confirmation screens are
+// in tests/unknownScaleSend.test.js.
+
+"use strict";
+
+// helpers.js reaches for both at module scope through the modules it pulls in.
+globalThis.chrome = {
+    storage: {
+        local: {
+            get: () => Promise.resolve({}),
+            set: () => Promise.resolve(),
+        },
+    },
+    runtime: { sendMessage: () => {} },
+};
+globalThis.document = {
+    getElementById: () => null,
+    createElement: () => ({ style: {}, classList: { toggle() {} } }),
+    body: { prepend: () => {} },
+    addEventListener: () => {},
+};
+
+const {
+    balanceLine,
+    balanceLinesForAddress,
+    addressHoldsFunds,
+} = require("../src/popup/views/helpers");
+const {
+    prices,
+    clearPrices,
+    getAddressValue,
+} = require("../src/shared/prices");
+const { state } = require("../src/shared/state");
+
+const NOVEL = "0x1111111111111111111111111111111111111111";
+
+// One stored tokenBalances row. `balance: null` is what balances.js writes for
+// a holding whose scale nothing knows; "0.0" is a quantity that was actually
+// established and is zero.
+function holding(balance) {
+    return {
+        address: NOVEL,
+        symbol: "NOVEL",
+        decimals: balance === null ? null : 18,
+        balance,
+        holders: 50000,
+    };
+}
+
+function address(balance) {
+    return {
+        address: "0x" + "a".repeat(40),
+        balance: "0",
+        tokenBalances: [holding(balance)],
+    };
+}
+
+// The quantity cell of a rendered row, which is the second of the two spans
+// inside the fixed-width span.
+function quantities(html) {
+    return [...html.matchAll(/<span>([^<]*)<\/span>/g)].map((m) => m[1]);
+}
+
+beforeEach(() => {
+    clearPrices();
+    state.wallets = [];
+    state.trackedTokens = [];
+    state.activeAddress = null;
+});
+
+afterEach(() => {
+    clearPrices();
+});
+
+describe("balanceLine", () => {
+    test("an unknown quantity and a zero one render differently", () => {
+        const unknown = balanceLine("NOVEL", null, null, NOVEL);
+        const zero = balanceLine("NOVEL", 0, null, NOVEL);
+        expect(unknown).not.toBe(zero);
+        expect(quantities(unknown)).toEqual(["NOVEL", "quantity unknown"]);
+        expect(quantities(zero)).toEqual(["NOVEL", "0.0000"]);
+    });
+
+    test("an unknown quantity produces no fiat figure, a zero one does", () => {
+        prices.NOVEL = 3;
+        const unknown = balanceLine("NOVEL", null, 3, NOVEL);
+        const zero = balanceLine("NOVEL", 0, 3, NOVEL);
+        // A price times an unknown quantity is not $0.00: that is the same
+        // claim of "nothing here" the quantity cell just refused to make.
+        expect(unknown).toContain(
+            '<span class="text-right text-muted flex-1">&nbsp;</span>',
+        );
+        expect(zero).toContain(
+            '<span class="text-right text-muted flex-1">$0.00</span>',
+        );
+    });
+});
+
+describe("balanceLinesForAddress", () => {
+    // The show-zero setting is a statement about zeroes. An unknown quantity
+    // is not one, so hiding the row would assert the zero nobody established
+    // and the holding would vanish from the list entirely.
+    test("hiding zero balances hides the zero row and keeps the unknown one", () => {
+        const unknown = balanceLinesForAddress(address(null), [], false);
+        const zero = balanceLinesForAddress(address("0.0"), [], false);
+        expect(unknown).not.toBe(zero);
+        expect(unknown).toContain("quantity unknown");
+        expect(unknown).toContain("NOVEL");
+        expect(zero).not.toContain("NOVEL");
+    });
+
+    test("showing zero balances still tells the two apart", () => {
+        const unknown = balanceLinesForAddress(address(null), [], true);
+        const zero = balanceLinesForAddress(address("0.0"), [], true);
+        expect(unknown).not.toBe(zero);
+        expect(quantities(unknown)).toEqual([
+            "ETH",
+            "0.0000",
+            "NOVEL",
+            "quantity unknown",
+        ]);
+        expect(quantities(zero)).toEqual(["ETH", "0.0000", "NOVEL", "0.0000"]);
+    });
+});
+
+describe("addressHoldsFunds", () => {
+    // Read by deleteAddress.js to decide whether removing the address is
+    // warned about. balances.js drops a row of zero base units before any
+    // scale is consulted, so a row that survived with no quantity is holding
+    // something, and the warning must err towards warning.
+    test("an unknown balance holds funds, a zero balance does not", () => {
+        expect(addressHoldsFunds(address(null))).toBe(true);
+        expect(addressHoldsFunds(address("0.0"))).toBe(false);
+    });
+});
+
+describe("getAddressValue", () => {
+    // `usd` is the value of what could be priced and `partial` says it is a
+    // floor rather than the total. An unpriceable holding is exactly what
+    // `partial` exists for; a holding of zero can neither add to the total nor
+    // make it incomplete.
+    test("an unknown balance makes the total partial, a zero balance does not", () => {
+        prices.ETH = 2000;
+        prices.NOVEL = 3;
+        const unknown = getAddressValue(address(null));
+        const zero = getAddressValue(address("0.0"));
+        expect(unknown).not.toEqual(zero);
+        expect(unknown).toEqual({ usd: 0, partial: true });
+        expect(zero).toEqual({ usd: 0, partial: false });
+    });
+
+    test("an unknown balance is not priced as zero of the token", () => {
+        prices.ETH = 2000;
+        prices.NOVEL = 3;
+        // The same row with a real quantity of 10 is worth $30. Neither that
+        // figure nor a confident $0.00 may be stated for the unknown one.
+        expect(getAddressValue(address("10.0"))).toEqual({
+            usd: 30,
+            partial: false,
+        });
+        expect(getAddressValue(address(null)).usd).toBe(0);
+        expect(getAddressValue(address(null)).partial).toBe(true);
+    });
+});

tests/unknownScaleSend.test.js

@@ -0,0 +1,455 @@
+// The Send and confirmation screens for a token whose explorer row carries no
+// decimals.
+//
+// https://git.eeqj.de/sneak/AutistMask/issues/349 made `fetchTokenBalances()`
+// store the explorer's own answer — `null` when it reported none — while the
+// scale a balance is DISPLAYED at is resolved separately: bundled list, then
+// the user's tracked tokens, then the explorer. The two are different
+// questions, and `tokenBalances[].decimals` only answers the second one.
+//
+// A reader that takes the stored field for the display scale therefore gets
+// `null` for a token the wallet does know the scale of. On the Send path that
+// null reaches `displayedDecimals()` inside `estimateGas()`, which throws, is
+// caught as an unavailable fee, and disables Send behind "The network fee could
+// not be estimated" — untrue, unactionable, and for a bundled token like WETH
+// or DAI whose scale was never in doubt. So the Send screen resolves the scale
+// the same way the balance list did, and only carries a null forward when that
+// resolution genuinely answers null.
+//
+// Driven through the real `fetchTokenBalances()`, the real Send review handler
+// and the real confirmation screen: a test that hand-wrote `decimals: null`
+// onto state would not show which of the two questions each screen is asking.
+//
+// The reader sites that are pure display are in tests/unknownScaleDisplay.test.js,
+// and what the fetcher stores is in tests/fabricatedDecimals.test.js.
+
+"use strict";
+
+jest.mock("../src/shared/log", () => ({
+    log: {
+        debugf: () => {},
+        infof: () => {},
+        warnf: () => {},
+        errorf: () => {},
+    },
+    debugFetch: jest.fn(),
+    setRuntimeDebug: () => {},
+    isDebug: () => false,
+}));
+
+// Everything the confirmation screen would reach the network for. The gas
+// estimate is the point: with a usable scale it must succeed, so that a failure
+// in these tests is a failure of the scale and not of the stub.
+const mockProvider = {
+    getFeeData: async () => ({
+        maxFeePerGas: 2000000000n,
+        gasPrice: 1000000000n,
+    }),
+    estimateGas: async () => 21000n,
+    getCode: async () => "0x",
+    getTransactionCount: async () => 1,
+    getBalance: async () => 0n,
+};
+
+jest.mock("../src/shared/balances", () => {
+    const actual = jest.requireActual("../src/shared/balances");
+    return { ...actual, getProvider: () => mockProvider };
+});
+
+// The confirmation screen's best-effort Etherscan label lookup is the one
+// thing here that reaches for fetch(). It is stubbed to fail, which is the
+// path it already takes offline; the assertion at the bottom of this file
+// pins that it is the ONLY fetch these screens make.
+global.fetch = jest.fn(() => {
+    throw new Error("tests must not perform network requests");
+});
+
+const { makeStorageStub } = require("./support/storageStub");
+global.chrome = { storage: makeStorageStub(), runtime: { sendMessage() {} } };
+
+// A stub DOM. Every id in index.html that these two views touch resolves to a
+// fresh recording element; nothing here depends on layout, only on what the
+// views write into the elements and which handlers they register.
+const elements = new Map();
+
+function makeEl(id) {
+    const handlers = new Map();
+    return {
+        id,
+        textContent: "",
+        innerHTML: "",
+        value: "",
+        disabled: false,
+        onclick: null,
+        style: {},
+        dataset: {},
+        classList: {
+            add() {},
+            remove() {},
+            toggle() {},
+            contains: () => false,
+        },
+        handlers,
+        addEventListener(name, fn) {
+            handlers.set(name, fn);
+        },
+        appendChild(child) {
+            return child;
+        },
+        querySelectorAll: () => [],
+        querySelector: () => null,
+        remove() {},
+        focus() {},
+    };
+}
+
+global.document = {
+    getElementById(id) {
+        if (!elements.has(id)) elements.set(id, makeEl(id));
+        return elements.get(id);
+    },
+    createElement: (tag) => makeEl(tag),
+    body: { prepend() {}, appendChild() {} },
+    addEventListener() {},
+};
+global.navigator = { clipboard: { writeText() {} } };
+
+const { parseUnits } = require("ethers");
+const { fetchTokenBalances } = require("../src/shared/balances");
+const { debugFetch } = require("../src/shared/log");
+const { state } = require("../src/shared/state");
+const {
+    displayedDecimals,
+    transferAmountUnits,
+} = require("../src/shared/transferAmount");
+const send = require("../src/popup/views/send");
+const confirmTx = require("../src/popup/views/confirmTx");
+const { TOKEN_BY_ADDRESS } = require("../src/shared/tokenList");
+
+const HOLDER = "0x" + "a".repeat(40);
+const SECOND_HOLDER = "0x" + "b".repeat(40);
+const RECIPIENT = "0xC0FfEE0000000000000000000000000000c0fFEe";
+const BLOCKSCOUT = "https://blockscout.example/api/v2";
+// Bundled, 18 decimals. The wallet knows this token's scale without asking
+// anyone, which is what makes an unsendable WETH a regression rather than a
+// refusal.
+const WETH = "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2";
+// Neither bundled nor tracked, so the explorer is the only possible source and
+// an omission there really is an unknown scale.
+const NOVEL = "0xE2E0000000000000000000000000000000000E2e";
+
+const FIVE_WETH = 5000000000000000000n;
+
+function row(token = {}, value = FIVE_WETH) {
+    return {
+        value: String(value),
+        token: {
+            type: "ERC-20",
+            address_hash: WETH,
+            symbol: "WETH",
+            name: "Wrapped Ether",
+            holders_count: "50000",
+            ...token,
+        },
+    };
+}
+
+// Fetch the explorer's rows through the real fetcher and put them exactly where
+// refreshBalances() puts them.
+async function fetchOnto(items) {
+    debugFetch.mockImplementation(async () => ({
+        ok: true,
+        status: 200,
+        statusText: "OK",
+        json: async () => items,
+    }));
+    const balances = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
+    state.wallets = [
+        {
+            name: "Wallet 1",
+            addresses: [
+                { address: HOLDER, balance: "1.0", tokenBalances: balances },
+            ],
+        },
+    ];
+    state.selectedWallet = 0;
+    state.selectedAddress = 0;
+    return balances;
+}
+
+// The same, for two addresses of one wallet holding the same contract. Sending
+// is from the first. Two addresses is what it takes to reach
+// explorerDecimals()'s disagreement check, which is only reachable across rows.
+async function fetchOntoBoth(itemsA, itemsB) {
+    debugFetch.mockImplementation(async () => ({
+        ok: true,
+        status: 200,
+        statusText: "OK",
+        json: async () => itemsA,
+    }));
+    const a = await fetchTokenBalances(HOLDER, BLOCKSCOUT, []);
+    debugFetch.mockImplementation(async () => ({
+        ok: true,
+        status: 200,
+        statusText: "OK",
+        json: async () => itemsB,
+    }));
+    const b = await fetchTokenBalances(SECOND_HOLDER, BLOCKSCOUT, []);
+    state.wallets = [
+        {
+            name: "Wallet 1",
+            addresses: [
+                { address: HOLDER, balance: "1.0", tokenBalances: a },
+                { address: SECOND_HOLDER, balance: "1.0", tokenBalances: b },
+            ],
+        },
+    ];
+    state.selectedWallet = 0;
+    state.selectedAddress = 0;
+    return { a, b };
+}
+
+function el(id) {
+    return global.document.getElementById(id);
+}
+
+// Press Review on the Send screen and return the txInfo it hands the
+// confirmation screen.
+async function reviewSend(tokenAddress, amount) {
+    let handed = null;
+    send.init({ showConfirmTx: (info) => (handed = info) });
+    state.selectedToken = tokenAddress;
+    el("send-token").value = tokenAddress;
+    el("send-to").value = RECIPIENT;
+    el("send-amount").value = amount;
+    await el("btn-send-review").handlers.get("click")();
+    return handed;
+}
+
+// show() kicks off the gas 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));
+}
+
+function text(id) {
+    return el(id).textContent;
+}
+
+function errors() {
+    return el("confirm-errors").innerHTML;
+}
+
+function sendDisabled() {
+    return el("btn-confirm-send").disabled;
+}
+
+beforeEach(() => {
+    elements.clear();
+    debugFetch.mockReset();
+    state.wallets = [];
+    state.trackedTokens = [];
+    state.selectedToken = null;
+    state.fraudContracts = [];
+    state.hideLowHolderTokens = false;
+    state.currentView = null;
+});
+
+describe("the Send screen resolves the scale rather than reading the stored one", () => {
+    test("the bundled list knows WETH, and the explorer row does not report a scale", async () => {
+        expect(TOKEN_BY_ADDRESS.get(WETH.toLowerCase()).decimals).toBe(18);
+        const balances = await fetchOnto([row()]);
+        // Stored: the explorer's own answer, which is nothing. Reading THIS is
+        // what carried a null into the fee estimate.
+        expect(balances[0].decimals).toBeNull();
+        // Displayed: the bundled scale, so the quantity on screen is real.
+        expect(balances[0].balance).toBe("5.0");
+    });
+
+    test("the review hands the confirmation screen the resolved scale, not the stored null", async () => {
+        const balances = await fetchOnto([row()]);
+        const txInfo = await reviewSend(WETH, "1.5");
+        expect(txInfo.tokenDecimals).toBe(18);
+        expect(txInfo.tokenDecimals).not.toBe(balances[0].decimals);
+        expect(txInfo.tokenBalance).toBe("5.0");
+    });
+
+    test("that scale estimates a fee and leaves Send enabled", async () => {
+        await fetchOnto([row()]);
+        const txInfo = await reviewSend(WETH, "1.5");
+        confirmTx.show(txInfo);
+        await settle();
+        // The regression: displayedDecimals(null) threw in estimateGas(), the
+        // catch reported the fee as unknown, and Send stayed disabled behind a
+        // message about the network fee that no retry could clear.
+        expect(text("confirm-fee-amount")).not.toBe("Unable to estimate");
+        expect(text("confirm-fee-amount")).toContain("ETH");
+        expect(errors()).toBe("");
+        expect(sendDisabled()).toBe(false);
+    });
+
+    test("and the transfer encodes at the scale that was displayed", async () => {
+        await fetchOnto([row()]);
+        const txInfo = await reviewSend(WETH, "1.5");
+        // The two calls confirmTx makes with this field: the gas estimate's
+        // scale, and the encode, which compares it against the contract's own
+        // decimals() before parsing.
+        expect(displayedDecimals(txInfo.tokenDecimals)).toBe(18);
+        expect(
+            transferAmountUnits(txInfo.amount, txInfo.tokenDecimals, 18n),
+        ).toBe(parseUnits("1.5", 18));
+    });
+
+    test("a token nothing knows the scale of is still refused, and says why", async () => {
+        await fetchOnto([
+            row({ address_hash: NOVEL, symbol: "NOVEL", name: "Novel Token" }),
+        ]);
+        const txInfo = await reviewSend(NOVEL, "1.5");
+        // No fallback was introduced: resolution answers null here, and the
+        // null is what goes forward.
+        expect(txInfo.tokenDecimals).toBeNull();
+        expect(txInfo.tokenBalance).toBeNull();
+        confirmTx.show(txInfo);
+        await settle();
+        expect(text("confirm-balance")).toBe("unknown (NOVEL)");
+        expect(errors()).toContain("This token&#39;s balance is unknown");
+        expect(sendDisabled()).toBe(true);
+    });
+});
+
+// balances.js resolves the display scale WITHOUT `wallets`, so its explorer leg
+// is the row it is formatting. send.js resolves WITH `wallets`, so its explorer
+// leg is explorerDecimals(), which answers null when two addresses report
+// different scales for one contract — the check that must apply before a scale
+// encodes a transfer. The two therefore disagree exactly here, and a stored
+// balance formatted at a scale the Send screen just refused is not a balance it
+// may state: it would leave validateTransfer() satisfied, the unknown-balance
+// sentence unfired, and the fee-estimate failure as the only thing on screen.
+describe("a scale the explorer's own rows disagree about", () => {
+    // 5000000 units at the "6" address A reports, 5e18 at the "18" address B
+    // reports: both format to "5.0", so the disagreement is in the scale alone
+    // and not in the quantity.
+    function novel(decimals, value) {
+        return row(
+            {
+                address_hash: NOVEL,
+                symbol: "NOVEL",
+                name: "Novel Token",
+                decimals,
+            },
+            value,
+        );
+    }
+
+    test("is stored per row, because storage holds the explorer's own answer", async () => {
+        const { a, b } = await fetchOntoBoth(
+            [novel("6", 5000000n)],
+            [novel("18", FIVE_WETH)],
+        );
+        expect(a[0].decimals).toBe(6);
+        expect(a[0].balance).toBe("5.0");
+        expect(b[0].decimals).toBe(18);
+    });
+
+    test("resolves to null on the Send screen, and takes the balance with it", async () => {
+        await fetchOntoBoth([novel("6", 5000000n)], [novel("18", FIVE_WETH)]);
+        const txInfo = await reviewSend(NOVEL, "1.5");
+        expect(txInfo.tokenDecimals).toBeNull();
+        // The regression this closes: null scale alongside a non-null balance.
+        expect(txInfo.tokenBalance).toBeNull();
+    });
+
+    test("so the user is told the balance is unknown, not only that the fee failed", async () => {
+        await fetchOntoBoth([novel("6", 5000000n)], [novel("18", FIVE_WETH)]);
+        const txInfo = await reviewSend(NOVEL, "1.5");
+        confirmTx.show(txInfo);
+        await settle();
+        // Before the fix: "5.0 NOVEL", an empty confirm-errors, and
+        // confirm-fee-unknown-error — "the network fee could not be
+        // estimated... please go back and try again" — as the only explanation
+        // for a screen that can never proceed.
+        expect(errors()).not.toBe("");
+        expect(errors()).toContain("This token&#39;s balance is unknown");
+        expect(text("confirm-balance")).toBe("unknown (NOVEL)");
+        expect(sendDisabled()).toBe(true);
+        // The fee line still reports the estimate as unavailable, because it
+        // genuinely is — displayedDecimals() refuses the same missing scale.
+        // What changed is that it is no longer the ONLY thing on the screen,
+        // and no longer the only offered explanation. This is exactly how the
+        // token nothing knows the scale of already behaved.
+        expect(text("confirm-fee-amount")).toBe("Unable to estimate");
+        expect(el("confirm-fee-unknown-error").style.visibility).toBe(
+            "visible",
+        );
+    });
+
+    test("while agreeing rows leave the scale usable", async () => {
+        await fetchOntoBoth([novel("6", 5000000n)], [novel("6", 5000000n)]);
+        const txInfo = await reviewSend(NOVEL, "1.5");
+        expect(txInfo.tokenDecimals).toBe(6);
+        expect(txInfo.tokenBalance).toBe("5.0");
+        confirmTx.show(txInfo);
+        await settle();
+        expect(text("confirm-balance")).toBe("5.0 NOVEL");
+        expect(errors()).toBe("");
+        expect(sendDisabled()).toBe(false);
+    });
+});
+
+describe("the confirmation screen tells an unknown balance from a zero one", () => {
+    function txInfo(tokenBalance) {
+        return {
+            from: HOLDER,
+            to: RECIPIENT,
+            ensName: null,
+            amount: "1.5",
+            token: NOVEL,
+            balance: "1.0",
+            tokenSymbol: "NOVEL",
+            tokenBalance,
+            tokenDecimals: tokenBalance === null ? null : 18,
+        };
+    }
+
+    async function render(tokenBalance) {
+        state.wallets = [
+            {
+                name: "Wallet 1",
+                addresses: [
+                    { address: HOLDER, balance: "1.0", tokenBalances: [] },
+                ],
+            },
+        ];
+        state.selectedWallet = 0;
+        state.selectedAddress = 0;
+        confirmTx.show(txInfo(tokenBalance));
+        await settle();
+        return { balance: text("confirm-balance"), errors: errors() };
+    }
+
+    test("the balance line states unknown rather than a quantity of zero", async () => {
+        const unknown = await render(null);
+        const zero = await render("0.0");
+        expect(unknown.balance).not.toBe(zero.balance);
+        expect(unknown.balance).toBe("unknown (NOVEL)");
+        expect(zero.balance).toBe("0.0 NOVEL");
+    });
+
+    // Both hit INSUFFICIENT_TOKEN — an unknown balance is treated as nothing to
+    // spend from, which is the fail-closed side — but "you have 0.0" is a claim
+    // about the holding, and this one has no established quantity to claim.
+    test("the insufficient-balance message names the reason, not a figure", async () => {
+        const unknown = await render(null);
+        const zero = await render("0.0");
+        expect(unknown.errors).not.toBe(zero.errors);
+        expect(unknown.errors).toContain("This token&#39;s balance is unknown");
+        expect(unknown.errors).not.toContain("You have");
+        expect(zero.errors).toContain("You have 0.0 NOVEL");
+        expect(zero.errors).not.toContain("balance is unknown");
+    });
+});
+
+test("the only network these screens reached for is the Etherscan label lookup", () => {
+    for (const [url] of global.fetch.mock.calls) {
+        expect(String(url)).toMatch(/^https:\/\/etherscan\.io\/address\//);
+    }
+});