fix: a V4 step of chained swap actions shows what the user receives (closes #563)

A V4 step's input side is the currency SETTLE or SETTLE_ALL names, else
the one currency some swap action spends and none buys; its output side
is the currency TAKE or TAKE_ALL names, else the one some swap action
buys and none spends. Amount and Min. received come from those actions,
summed when several exact-in actions each state one. A step with an
unread swap action is named only by SETTLE, SETTLE_ALL, TAKE and
TAKE_ALL, and shows no figure. A side a step with a swap action leaves
unknown shows no other step's token or figure. Before, the first swap
action set both sides, SETTLE_ALL and TAKE_ALL went unread, and a
SWAP_EXACT_OUT was read as spending its path's last currency.

Model: opus-5-5

README.md

@@ -362,6 +362,14 @@ are outside `make check`. Neither opens the popup from the toolbar button: both
 load its page in an ordinary tab, so what the toolbar popup itself adds, its
 size and its closing when it loses focus, is covered by neither.
 
+Each run builds its image under a tag of its own, `autistmask-e2e-chrome:` or
+`autistmask-e2e-firefox:` followed by twelve random hex digits, so two clones
+can run the same suite at once without one build taking the other's image away.
+The run removes that image, and its container if one is still running, after the
+suite passes or fails, on Ctrl-C, on `kill`, and when the terminal or SSH
+session it runs in closes. A run killed outright (`kill -9`) cannot clean up:
+its image stays under its tag until removed by hand with `docker image rm`.
+
 ### Chrome (`make test-e2e`)
 
 `make test-e2e` builds `dist/chrome/` and drives the **real popup in a real
@@ -479,6 +487,9 @@ papered over:
   forced by clicking Reveal and the settings gear in one page task, which a
   person cannot do; the case a person can hit, the first decrypt after the popup
   opens while libsodium is still loading, is not driven.
+- Approval windows open at 1280x720 whatever size the extension asks for, so
+  whether an approval screen fits its window is checked in the Firefox suite
+  only.
 
 Any test that drives a failure path on purpose declares the `console.error` it
 is about to provoke, via `errors.expect()`. That is not a mute: the declaration
@@ -560,9 +571,12 @@ the worker stopping. It starts Chromium itself, speaks the DevTools protocol
 over `--remote-debugging-pipe`, and attaches to pages only. Before raising the
 approvals it requires the worker to stop on its own with nothing pending, so a
 run in which something else keeps the worker running fails. The site is
-connected and the RPC endpoint set through the extension's own screens, against
-the loopback dApp page and stub node the Firefox suite also uses
-(`tests/e2e/dapp.js`). Unlike the suite above, it does not fail on page errors.
+connected, without "Remember my choice for this site", and the RPC endpoint set
+through the extension's own screens, against the loopback dApp page and stub
+node the Firefox suite also uses (`tests/e2e/dapp.js`). Once the worker has
+stopped, the run requires the site still to be told the address
+([#526](https://git.eeqj.de/sneak/AutistMask/issues/526)). Unlike the suite
+above, it does not fail on page errors.
 
 ### Firefox (`make test-e2e-firefox`)
 
@@ -573,7 +587,9 @@ suite), wallet creation through the UI, the Add Token screen, and the dApp round
 trips — `eth_requestAccounts`, `personal_sign`, `wallet_switchEthereumChain`
 rejected and then approved, `eth_sendTransaction`, and a closed approval window
 rejecting with EIP-1193 4001 — driven through the real content script,
-background page and approval windows.
+background page and approval windows. The `personal_sign` prompt is also
+required to fit its window without scrolling sideways, with the extension's
+pages at 170% zoom.
 
 The suite lives in `tests/e2e/firefox/`. Its WebDriver client (`driver.js`) has
 **no npm dependencies at all**: it is built on global `fetch` and
@@ -844,7 +860,11 @@ on the next event. Two consequences shape every recurring job in the background:
 - Module-level variables do not survive either. Anything that must be remembered
   across a restart goes in extension storage. `localStorage` does not exist in a
   service worker at all — the one remaining user of it, `src/shared/ens.js`,
-  runs only in the popup and is marked as such.
+  runs only in the popup and is marked as such. The sites allowed without
+  "Remember my choice for this site" are kept in the browser's session storage
+  (`storage.session`), which outlives the worker but not the browser, so such a
+  connection lasts until it is ended or the browser closes. Firefox has session
+  storage from version 115, the minimum `manifest/firefox.json` declares.
 
 Pending approvals are the exception: an approval waiting for the user, and the
 site's request waiting on it, live only in the worker's memory, and only the
@@ -947,8 +967,16 @@ discoverable.
   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
   this scale.
-- **360x600 popup**: Standard browser extension popup dimensions. The UI is
-  designed for this fixed viewport.
+- **396x600 popup**: The page is 396 pixels wide (`body` in
+  `src/popup/styles/main.css`), and 600 pixels is as tall as the browser lets
+  the toolbar popup grow. The UI is designed for this fixed viewport. The window
+  an approval opens in is given the same size. The browser counts the window's
+  frame in that width, and a screen taller than the window gives some of it to a
+  vertical scrollbar, so once the approval's screen is up the page widens its
+  window by however far it would scroll sideways, scaled by the browser's zoom.
+  Firefox draws some zoom steps a little larger than the zoom it reports, so the
+  page measures again once the window has grown, and widens it again while it
+  still falls short.
 
 #### No Layout Shift
 
@@ -1143,8 +1171,8 @@ read:
   amount of one step that names an input token or amount: the last
   `PERMIT2_PERMIT` step if there is one, otherwise the first V2 or V3 exact-in,
   V2 exact-out, `WRAP_ETH` or V4 swap step. A V2 exact-out step gives its
-  `amountInMax`, and a V4 swap step the `amountIn` of its first readable
-  exact-in action.
+  `amountInMax`, and a V4 swap step the `amountIn` of the swap action that
+  spends its input currency, as described below.
 - `Whatever an earlier step sent to the pair (V2 already paid)`: the swap's
   `Amount` line, when the amount it shows is a V2 exact-in `amountIn` of zero.
   The router reads that zero as "the pair already holds the input tokens": the
@@ -1166,16 +1194,37 @@ The swap's `Token In` and `Token Out` lines name a currency, not an amount; each
 reads `Unknown (not named in the calldata)` when the decoder found no token for
 that side, or `Unknown (could not be decoded)` instead when a V4 swap action in
 the transaction could not be read (see Transaction Decoding below). A V4 step
-whose swap action could not be read still sets each side as a swap step does,
-and a side its `SETTLE` or `TAKE` did not name is then unknown: no other step's
-token or figure is shown for it. An `UNWRAP_WETH` step makes `Token Out` ETH
-only when the output side is WETH, on mainnet or Sepolia, or when no step set
-the output side; a WETH `Min. received` figure then reads in ETH. Otherwise
-`Token Out` and `Min. received` keep the output side's own token and figure,
-whether the swap was paid in ETH or in a token: a V2 exact-out swap that buys
-USDC and then unwraps the WETH it did not spend shows USDC. The token permission
-warning on the signature screen has its own amount wording, including `Unknown`;
-the SignApproval section below describes it.
+with a swap action sets both sides as a swap step does, following three rules:
+
+1. Its input side is the currency its `SETTLE` or `SETTLE_ALL` names, or else
+   the one currency that some swap action in the step spends and none buys. Its
+   output side is the currency its `TAKE` or `TAKE_ALL` names, or else the one
+   currency that some swap action buys and none spends. If there is not exactly
+   one such currency, that side is unknown, and no other step's token or figure
+   is shown for it. A step that buys WETH with USDT and USDC with that WETH,
+   with nothing naming its sides, reads `Swap USDT → USDC`.
+2. `Amount` is the `amountIn` of the swap action that spends the input currency.
+   If several exact-in actions spend it, each with a stated amount, it is their
+   sum; in any other case there is no `Amount` line. The decoder reads no amount
+   from an exact-out action, and an open delta is not a stated amount.
+   `Min. received` is found the same way, from the `amountOutMin` of the actions
+   that buy the output currency.
+3. If any swap action in the step could not be read, only `SETTLE`,
+   `SETTLE_ALL`, `TAKE` and `TAKE_ALL` name its sides, and there is no `Amount`
+   or `Min. received` line. A side they did not name is unknown, and no other
+   step's token or figure is shown for it.
+
+A V4 step with no swap action sets only the sides its `SETTLE`, `SETTLE_ALL`,
+`TAKE` or `TAKE_ALL` names.
+
+An `UNWRAP_WETH` step makes `Token Out` ETH only when the output side is WETH,
+on mainnet or Sepolia, or when no step set the output side; a WETH
+`Min. received` figure then reads in ETH. Otherwise `Token Out` and
+`Min. received` keep the output side's own token and figure, whether the swap
+was paid in ETH or in a token: a V2 exact-out swap that buys USDC and then
+unwraps the WETH it did not spend shows USDC. The token permission warning on
+the signature screen has its own amount wording, including `Unknown`; the
+SignApproval section below describes it.
 
 The swap's `Deadline` line is the router's deadline as a UTC date and time, e.g.
 `2026-02-27 08:25:51`. A JavaScript date reaches only to 275760-09-13 00:00:00
@@ -1531,8 +1580,14 @@ view would leave a wallet one click from deletion.
 - **Transitions**:
     - "Import" with a valid entry and a matching password of at least 12
       characters → creates the wallet, clears the navigation stack, and →
-      **Home**. The phrase and xprv modes then scan for further used addresses
-      and report the count as a flash message.
+      **Home**. When no address is active yet, as on the first wallet, the new
+      wallet's first address becomes the active one. The phrase and xprv modes
+      then scan for further used addresses and report the count as a flash
+      message. When the scan finds two or more used addresses, they replace the
+      wallet's list, which then holds the first address only if it was used. If
+      the first address was active and is not in the new list, the new list's
+      first address becomes the active one and `AUTISTMASK_ACTIVE_CHANGED` is
+      broadcast.
     - "Import" with a missing, short or mismatched password → full-sentence
       error on the error line, no screen change
     - "Import" with an invalid entry or a duplicate wallet or address → flash
@@ -1659,7 +1714,13 @@ view would leave a wallet one click from deletion.
 - **Transitions**:
     - "Review" (valid inputs, ENS resolved) → **ConfirmTx**
     - "Review" with an unresolvable ENS name or an invalid amount → flash
-      message, no screen change
+      message, no screen change. An amount is valid when it is a number above
+      zero, written as digits with at most one decimal point, with nothing but
+      zeros after the token's last decimal place. ETH has 18 places, and a token
+      with more, or with an unknown number, is held to 18. Zeros past those
+      places leave the amount unchanged, so `1.0000000` of a 6-place token
+      passes and is sent as exactly 1. ConfirmTx makes the same check before
+      anything can be sent
     - "Back" → previous screen (Home, AddressDetail, or AddressToken)
 
 #### ConfirmTx (`confirm-tx`)
@@ -1903,7 +1964,7 @@ view would leave a wallet one click from deletion.
       under any address, with remove buttons
     - Connected Sites: the origins of the sites allowed without "Remember my
       choice" that are still connected, with remove buttons. Only the background
-      holds these, in memory, and Settings asks it for them with
+      holds these, in session storage, and Settings asks it for them with
       `AUTISTMASK_GET_CONNECTED_SITES`
     - Denied Sites: the origins remembered as denied, under any address, with
       remove buttons
@@ -1922,9 +1983,10 @@ view would leave a wallet one click from deletion.
       its origin is dropped from Allowed Sites under every address, and
       `AUTISTMASK_REMOVE_SITE` has the background end every connection approved
       without "Remember" from that origin, under any address, and send
-      `accountsChanged` with an empty list to the open tabs of that origin. The
-      same host under another scheme or port is another site and is left alone.
-      Only the extension's own pages may send either message
+      `accountsChanged` with an empty list to the open tabs of that origin.
+      Settings waits for the background's answer before it draws the lists
+      again. The same host under another scheme or port is another site and is
+      left alone. Only the extension's own pages may send either message
     - `[x]` on a denied site → forgets the refusal, in place; it connects
       nothing and tells the background nothing
     - Ten clicks on the version → reveals the Debug well (no screen change)
@@ -1985,8 +2047,8 @@ view would leave a wallet one click from deletion.
       (`src/shared/walletDelete.js`)
     - Either way, every address the wallet held loses its site permissions of
       both kinds: the remembered ones in storage, and the connections approved
-      without "Remember", which only the background holds, in memory, and drops
-      on `AUTISTMASK_ADDRESSES_REMOVED`
+      without "Remember", which only the background holds, in session storage,
+      and drops on `AUTISTMASK_ADDRESSES_REMOVED`
     - "Confirm Delete" (wrong password) → "That password is incorrect. Please
       try again." on the error line, nothing deleted
     - "I have lost my password" → **DeleteWalletLostPassword**
@@ -2099,8 +2161,8 @@ view would leave a wallet one click from deletion.
   one in this wallet follows the splice.
 - The address loses its site permissions of both kinds, whether or not it was
   the active one: the remembered ones in storage, and any connection approved
-  without "Remember", which only the background holds, in memory, and drops on
-  `AUTISTMASK_ADDRESSES_REMOVED`.
+  without "Remember", which only the background holds, in session storage, and
+  drops on `AUTISTMASK_ADDRESSES_REMOVED`.
 - The wallet's derivation counter (`nextIndex`) is not rewound, so "+" derives a
   fresh address rather than handing back the one just removed.
 
@@ -2129,14 +2191,22 @@ view would leave a wallet one click from deletion.
   `wallet_requestPermissions` and is on neither the allowed nor the denied list.
   A site is its full origin, `scheme://host[:port]`, on both lists and for a
   connection allowed without "Remember": a choice for `https://dapp.example`
-  says nothing about `http://dapp.example` or another port of that host. The
-  background script prefers the toolbar popup (`action.openPopup()`) and falls
-  back to a separate popup window (`src/background/index.js`,
-  `requestApproval()`). Only one exists per site at a time: a further connection
-  request from a site whose prompt is still unanswered is refused with EIP-1193
-  code `-32002` and opens no new prompt. If that prompt was in a toolbar popup
-  that closed before it connected, and the toolbar popup has since been set to
-  open something else, the refused request shows that prompt again.
+  says nothing about `http://dapp.example` or another port of that host. A
+  request whose origin has no host names no site, so it is refused with EIP-1193
+  code `4100` and opens no prompt. Two such origins are `null`, which the
+  browser reports for a page with an opaque origin, such as one its server
+  sandboxes with a Content-Security-Policy, and `file://`, which Chrome reports
+  for a local file. Nor is such a page told the active address by
+  `accountsChanged`, even at a connected site's URL: the background names the
+  origin of the tab's URL on the event, and the content script passes the
+  address on only to a page whose own origin is that one. The background script
+  prefers the toolbar popup (`action.openPopup()`) and falls back to a separate
+  popup window (`src/background/index.js`, `requestApproval()`). Only one exists
+  per site at a time: a further connection request from a site whose prompt is
+  still unanswered is refused with EIP-1193 code `-32002` and opens no new
+  prompt. If that prompt was in a toolbar popup that closed before it connected,
+  and the toolbar popup has since been set to open something else, the refused
+  request shows that prompt again.
 - **Elements**:
     - "Connection Request" heading
     - Phishing warning banner (shown when the hostname is on the phishing
@@ -2168,8 +2238,10 @@ view would leave a wallet one click from deletion.
   one shown and signed in place of the node's estimate, but the node still
   estimates the transaction with that limit, as the check that it neither
   reverts nor runs out of gas; a request that gives both with different values
-  is refused. A request that cannot be populated — unreachable node, reverting
-  gas estimate — opens no window and is failed back to the site. Only one
+  is refused with EIP-1474 code `-32602`. A request that cannot be populated —
+  unreachable node, reverting gas estimate — opens no window and is failed back
+  to the site, with the node's own error code and data when the node refused it,
+  so the site can decode a revert, and with `-32603` otherwise. Only one
   transaction approval exists at a time: populating fixes the nonce, so a second
   `eth_sendTransaction` arriving while one is unanswered is refused with
   EIP-1193 code `-32002` rather than being populated at the same nonce. It opens

manifest/firefox.json

@@ -27,7 +27,8 @@
     "web_accessible_resources": ["src/content/inpage.js"],
     "browser_specific_settings": {
         "gecko": {
-            "id": "autistmask@sneak.berlin"
+            "id": "autistmask@sneak.berlin",
+            "strict_min_version": "115.0"
         }
     }
 }

script/test-e2e

@@ -22,13 +22,29 @@ set -eu
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
 ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 
-IMAGE="$("$SCRIPT_DIR/projectname")-e2e-chrome"
-
-IIDFILE=""
+# Each run builds, runs and then removes an image under a tag of its own.
+# Under one tag shared by every run, a second clone's build moves the tag
+# off this run's image, and the image store can then delete that untagged
+# image before or while this run uses it. The tag is random rather than
+# $$ because CI jobs share one docker daemon, but each job's container
+# numbers its processes from scratch.
+SUFFIX="$(od -An -N6 -tx1 /dev/urandom | tr -d ' \n')"
+NAME="$("$SCRIPT_DIR/projectname")-e2e-chrome"
+IMAGE="$NAME:$SUFFIX"
+# Each docker run below uses this container name: docker run --rm returns
+# only once its container is removed, so no run meets the one before it.
+CONTAINER="$NAME-$SUFFIX"
 
 cleanup() {
-    if [ -n "$IIDFILE" ]; then
-        rm -f "$IIDFILE"
+    # After a third Ctrl-C docker's client exits whether or not the
+    # container has stopped, and a container still running keeps the image
+    # in use.
+    if docker container inspect "$CONTAINER" >/dev/null 2>&1; then
+        docker container rm -f "$CONTAINER" >/dev/null
+    fi
+    # No image to remove when the build failed or was interrupted.
+    if docker image inspect "$IMAGE" >/dev/null 2>&1; then
+        docker image rm "$IMAGE" >/dev/null
     fi
 }
 
@@ -40,22 +56,16 @@ main() {
         exit 1
     fi
 
-    IIDFILE="$(mktemp)"
     trap cleanup EXIT
-    trap 'cleanup; exit 130' INT TERM
+    # HUP: the terminal or SSH session running the suite closed.
+    trap 'cleanup; exit 130' HUP INT TERM
 
     echo "Building the Chrome e2e image (extension included)..."
     # --no-cache: the image build runs make build and its checks, and a
     # cached layer is a check that did not run.
-    docker build --no-cache --iidfile "$IIDFILE" -t "$IMAGE" \
-        -f tests/e2e/Dockerfile .
+    docker build --no-cache -t "$IMAGE" -f tests/e2e/Dockerfile .
 
     echo "Running e2e suite in the pinned Playwright container..."
-    # The image is run by ID, not by tag: where two clones of this repo run
-    # the suite at once, the other build can move the tag between this
-    # build and this run, and the suite would then silently test the other
-    # checkout.
-    #
     # --ipc=host: Chromium's shared-memory needs more than the default
     #   64MB /dev/shm or renderers crash.
     # HOME=/tmp: the image's root home is not a reliable place for the
@@ -75,11 +85,12 @@ main() {
     #   probe. The image is pinned by digest, so this can only ever bite
     #   on a deliberate bump.
     docker run --rm \
+        --name "$CONTAINER" \
         --ipc=host \
         -e HOME=/tmp \
         -e PW_EXPERIMENTAL_SERVICE_WORKER_NETWORK_EVENTS=1 \
         -e "E2E_TRACE_NETWORK=${E2E_TRACE_NETWORK:-0}" \
-        "$(cat "$IIDFILE")" \
+        "$IMAGE" \
         node tests/e2e/run.js
 
     # Where chrome.storage.local lives, and what moves it: two unpacked loads
@@ -93,9 +104,10 @@ main() {
     # --host-resolver-rules=MAP * ~NOTFOUND so nothing it does can leave.
     echo "Running the extension-id and storage-partition observations..."
     docker run --rm \
+        --name "$CONTAINER" \
         --ipc=host \
         -e HOME=/tmp \
-        "$(cat "$IIDFILE")" \
+        "$IMAGE" \
         node tests/e2e/storagePartition.js
 
     # Approvals left open for seven minutes in minimized windows, past the
@@ -105,9 +117,10 @@ main() {
     # attached to. It reaches nothing but its own loopback server.
     echo "Running the approvals left open for seven minutes..."
     docker run --rm \
+        --name "$CONTAINER" \
         --ipc=host \
         -e HOME=/tmp \
-        "$(cat "$IIDFILE")" \
+        "$IMAGE" \
         node tests/e2e/slowApproval.js
 }
 

script/test-e2e-firefox

@@ -21,13 +21,23 @@ set -eu
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
 ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 
-IMAGE="$("$SCRIPT_DIR/projectname")-e2e-firefox"
-
-IIDFILE=""
+# A tag and a container name of this run's own, as in script/test-e2e,
+# which says why.
+SUFFIX="$(od -An -N6 -tx1 /dev/urandom | tr -d ' \n')"
+NAME="$("$SCRIPT_DIR/projectname")-e2e-firefox"
+IMAGE="$NAME:$SUFFIX"
+CONTAINER="$NAME-$SUFFIX"
 
 cleanup() {
-    if [ -n "$IIDFILE" ]; then
-        rm -f "$IIDFILE"
+    # After a third Ctrl-C docker's client exits whether or not the
+    # container has stopped, and a container still running keeps the image
+    # in use.
+    if docker container inspect "$CONTAINER" >/dev/null 2>&1; then
+        docker container rm -f "$CONTAINER" >/dev/null
+    fi
+    # No image to remove when the build failed or was interrupted.
+    if docker image inspect "$IMAGE" >/dev/null 2>&1; then
+        docker image rm "$IMAGE" >/dev/null
     fi
 }
 
@@ -39,22 +49,16 @@ main() {
         exit 1
     fi
 
-    IIDFILE="$(mktemp)"
     trap cleanup EXIT
-    trap 'cleanup; exit 130' INT TERM
+    # HUP: the terminal or SSH session running the suite closed.
+    trap 'cleanup; exit 130' HUP INT TERM
 
     echo "Building the pinned Firefox e2e image (extension included)..."
     # --no-cache: the image build runs make build and its checks, and a
     # cached layer is a check that did not run.
-    docker build --no-cache --iidfile "$IIDFILE" -t "$IMAGE" \
-        -f tests/e2e/firefox/Dockerfile .
+    docker build --no-cache -t "$IMAGE" -f tests/e2e/firefox/Dockerfile .
 
     echo "Running the Firefox e2e suite..."
-    # The image is run by ID, not by tag: where two clones of this repo run
-    # the suite at once, the other build can move the tag between this
-    # build and this run, and the suite would then silently test the other
-    # checkout.
-    #
     # --shm-size=1g: Firefox needs more than the default 64MB /dev/shm.
     # --network none: the suite stubs nothing, so this is what keeps the
     #   run offline and deterministic. The extension swallows its own
@@ -69,10 +73,11 @@ main() {
     # "CanCreateUserNamespace() clone() failure: EPERM" on startup here;
     # it is cosmetic and headless Firefox runs fine without it.
     docker run --rm \
+        --name "$CONTAINER" \
         --shm-size=1g \
         --network none \
         -e HOME=/tmp \
-        "$(cat "$IIDFILE")" \
+        "$IMAGE" \
         node tests/e2e/firefox/run.js dist/firefox
 
     # The install/uninstall/re-install property, against the packaged XPI
@@ -82,10 +87,11 @@ main() {
     # and the suite above shares one session throughout.
     echo "Running the Firefox re-install suite against the packaged XPI..."
     docker run --rm \
+        --name "$CONTAINER" \
         --shm-size=1g \
         --network none \
         -e HOME=/tmp \
-        "$(cat "$IIDFILE")" \
+        "$IMAGE" \
         node tests/e2e/firefox/reinstall.js
 }
 

src/background/index.js

@@ -26,6 +26,7 @@ const {
     typedDataMessageRefusal,
     typedDataChainRefusal,
     failureIsRetryable,
+    nodeError,
     describeTxFailure,
     sameAddress,
     ApprovalMismatchError,
@@ -48,6 +49,9 @@ const {
     actionApi,
     getPlatformInfo,
     runtimeApi,
+    sessionStorageGet,
+    sessionStorageRemove,
+    sessionStorageSet,
     tabsQuery,
     tabsSendMessage,
     windowsApi,
@@ -60,12 +64,31 @@ const runtime = runtimeApi();
 const windowsNs = windowsApi();
 const actionNs = actionApi();
 
-// Connected sites (in-memory, non-persisted): { "origin:address": true }
+// Connections the user allowed without "Remember my choice for this site".
+// Each is one item in the browser's session storage, key
+// origin + ":" + address and value true, and session storage holds nothing
+// else. Session storage outlives this worker being stopped when idle and
+// started again, so such a connection lasts until it is ended below or the
+// browser closes. One item per connection means that making one is a single
+// write, and two never overwrite each other.
 //
 // A site is its full origin (scheme://host[:port]), here and in the
 // remembered allowedSites/deniedSites lists alike: a grant to
 // https://dapp.example says nothing about http://dapp.example or another port.
-const connectedSites = {};
+// An origin can carry a port, so the address is what follows the key's last
+// colon and the origin is what precedes it.
+async function isConnected(origin, address) {
+    const key = origin + ":" + address;
+    const items = await sessionStorageGet(key);
+    return items[key] === true;
+}
+
+// End every connection allowed without "Remember" whose key `ends` returns
+// true for.
+async function endConnections(ends) {
+    const keys = Object.keys(await sessionStorageGet(null)).filter(ends);
+    if (keys.length > 0) await sessionStorageRemove(keys);
+}
 
 // Pending approval requests: { id: { origin, resolve } }
 const pendingApprovals = {};
@@ -272,6 +295,21 @@ function failureError(err) {
     return { code: INTERNAL_ERROR_CODE, message: INTERNAL_ERROR_MESSAGE };
 }
 
+// The EIP-1193 error for a request that failed, with `message` as the
+// sentence the page is shown. `rpcError` holds the JSON-RPC code and data the
+// failure carries, if any: the node's own when the node refused the request,
+// passed on unchanged so a site can tell a revert from any other failure and
+// decode its revert data. A failure with no numeric code is the wallet's own,
+// and is answered with the internal error code above.
+function requestError(message, rpcError) {
+    if (rpcError && typeof rpcError.code === "number") {
+        const error = { code: rpcError.code, message };
+        if (rpcError.data !== undefined) error.data = rpcError.data;
+        return error;
+    }
+    return { code: INTERNAL_ERROR_CODE, message };
+}
+
 // The active address of a profile snapshot. Pure, and taking the snapshot as
 // an argument rather than reading storage itself: a handler that has already
 // read state must not answer "which account is this" from a SECOND, later read
@@ -317,7 +355,8 @@ function extractHostname(origin) {
     }
 }
 
-// Proxy an RPC call to the Ethereum node
+// Proxy an RPC call to the Ethereum node. An error the node answers with is
+// thrown with the node's own JSON-RPC `code` and `data` on it, for the page.
 async function proxyRpc(method, params) {
     const rpcUrl = await getRpcUrl();
     const resp = await debugFetch(rpcUrl, {
@@ -332,7 +371,10 @@ async function proxyRpc(method, params) {
     });
     const json = await resp.json();
     if (json.error) {
-        throw new Error(json.error.message || "RPC error");
+        const err = new Error(json.error.message || "RPC error");
+        err.code = json.error.code;
+        err.data = json.error.data;
+        throw err;
     }
     return json.result;
 }
@@ -453,7 +495,10 @@ function releaseApproval(approval) {
 // the result on the floor, so a rejection here would be unhandled.
 async function openApprovalWindow(id) {
     const popupUrl = runtime.getURL("src/popup/index.html?approval=" + id);
-    const popupWidth = 360;
+    // As wide as the page: body in src/popup/styles/main.css. The browser
+    // counts the window's frame in this width; the page itself adds back
+    // whatever the frame takes (src/popup/index.js).
+    const popupWidth = 396;
     const popupHeight = 600;
 
     let currentWin = null;
@@ -473,7 +518,7 @@ async function openApprovalWindow(id) {
     // Centred on a browser window only. The last focused window can be
     // another approval window still open, and centring on one can give a
     // position the browser refuses ("Bounds must be at least 50% within
-    // visible screen space"): headless Chrome reports this 360x600 popup as
+    // visible screen space"): headless Chrome reports this 396x600 popup as
     // 1280x720. The request then failed with no window at all. Over a popup,
     // the browser picks the position.
     if (currentWin && currentWin.type === "normal") {
@@ -725,7 +770,7 @@ async function handleConnectionRequest(origin) {
     const s = await getState();
     const activeAddress = activeAddressOf(s);
     if (!activeAddress) {
-        return { error: { message: "No accounts available" } };
+        return { error: { code: 4100, message: "No accounts available" } };
     }
 
     const allowed = s.allowedSites[activeAddress] || [];
@@ -741,10 +786,10 @@ async function handleConnectionRequest(origin) {
         };
     }
 
-    // Check allowed list or in-memory connected
+    // Check allowed list or a connection allowed without "Remember"
     if (
         allowed.includes(origin) ||
-        connectedSites[origin + ":" + activeAddress]
+        (await isConnected(origin, activeAddress))
     ) {
         return { result: [activeAddress] };
     }
@@ -781,7 +826,7 @@ async function handleConnectionRequest(origin) {
         if (decision.remember) {
             await rememberSiteChoice("allowedSites", activeAddress, origin);
         } else {
-            connectedSites[origin + ":" + activeAddress] = true;
+            await sessionStorageSet({ [origin + ":" + activeAddress]: true });
         }
         return { result: [activeAddress] };
     } else {
@@ -835,7 +880,7 @@ async function handleRpc(method, params, origin) {
         const allowed = s.allowedSites[activeAddress] || [];
         if (
             allowed.includes(origin) ||
-            connectedSites[origin + ":" + activeAddress]
+            (await isConnected(origin, activeAddress))
         ) {
             return { result: [activeAddress] };
         }
@@ -871,7 +916,7 @@ async function handleRpc(method, params, origin) {
         const allowed = s.allowedSites[activeAddress] || [];
         if (
             !allowed.includes(origin) &&
-            !connectedSites[origin + ":" + activeAddress]
+            !(await isConnected(origin, activeAddress))
         ) {
             return { error: { code: 4100, message: "Unauthorized" } };
         }
@@ -964,10 +1009,10 @@ async function handleRpc(method, params, origin) {
         const s = await getState();
         const activeAddress = activeAddressOf(s);
         const allowed = s.allowedSites[activeAddress] || [];
-        const isConnected =
+        const hasPermission =
             allowed.includes(origin) ||
-            connectedSites[origin + ":" + activeAddress];
-        if (!isConnected || !activeAddress) {
+            (await isConnected(origin, activeAddress));
+        if (!hasPermission || !activeAddress) {
             return { result: [] };
         }
         return {
@@ -989,12 +1034,12 @@ async function handleRpc(method, params, origin) {
         const s = await getState();
         const activeAddress = activeAddressOf(s);
         if (!activeAddress)
-            return { error: { message: "No accounts available" } };
+            return { error: { code: 4100, message: "No accounts available" } };
 
         const allowed = s.allowedSites[activeAddress] || [];
         if (
             !allowed.includes(origin) &&
-            !connectedSites[origin + ":" + activeAddress]
+            !(await isConnected(origin, activeAddress))
         ) {
             return { error: { code: 4100, message: "Unauthorized" } };
         }
@@ -1043,12 +1088,12 @@ async function handleRpc(method, params, origin) {
         const s = await getState();
         const activeAddress = activeAddressOf(s);
         if (!activeAddress)
-            return { error: { message: "No accounts available" } };
+            return { error: { code: 4100, message: "No accounts available" } };
 
         const allowed = s.allowedSites[activeAddress] || [];
         if (
             !allowed.includes(origin) &&
-            !connectedSites[origin + ":" + activeAddress]
+            !(await isConnected(origin, activeAddress))
         ) {
             return { error: { code: 4100, message: "Unauthorized" } };
         }
@@ -1090,12 +1135,13 @@ async function handleRpc(method, params, origin) {
             const result = await proxyRpc(method, params);
             return { result };
         } catch (e) {
-            // A node that answered with an error is reported as itself. The
-            // wallet being unable to read its own profile is not that, and it
-            // must not be flattened into a message with no code: it goes back
-            // to the dispatcher, which has the one answer for it.
+            // A node that answered with an error is reported as itself, with
+            // its own code and data. The wallet being unable to read its own
+            // profile is not that, and it must not be answered as an ordinary
+            // failure: it goes back to the dispatcher, which has the one
+            // answer for it.
             if (e instanceof StateUnusableError) throw e;
-            return { error: { message: e.message } };
+            return { error: requestError(e.message, e) };
         }
     }
 
@@ -1111,12 +1157,14 @@ async function handleRpc(method, params, origin) {
 async function handleSendTransaction(params, origin) {
     const s = await getState();
     const activeAddress = activeAddressOf(s);
-    if (!activeAddress) return { error: { message: "No accounts available" } };
+    if (!activeAddress) {
+        return { error: { code: 4100, message: "No accounts available" } };
+    }
 
     const allowed = s.allowedSites[activeAddress] || [];
     if (
         !allowed.includes(origin) &&
-        !connectedSites[origin + ":" + activeAddress]
+        !(await isConnected(origin, activeAddress))
     ) {
         return { error: { code: 4100, message: "Unauthorized" } };
     }
@@ -1170,7 +1218,7 @@ async function handleSendTransaction(params, origin) {
                 txParams,
             );
         } catch (e) {
-            return { error: { message: e.message } };
+            return { error: requestError(e.message, e) };
         }
 
         // Population is a network round trip, and the user can switch address
@@ -1180,10 +1228,9 @@ async function handleSendTransaction(params, origin) {
         // while the page is still waiting and nothing has been displayed.
         if (!sameAddress(await getActiveAddress(), activeAddress)) {
             return {
-                error: {
-                    message:
-                        "The active address changed while this transaction was being prepared, so it was not sent.",
-                },
+                error: requestError(
+                    "The active address changed while this transaction was being prepared, so it was not sent.",
+                ),
             };
         }
 
@@ -1229,10 +1276,6 @@ async function broadcastChainChanged(chainId) {
 
 // Broadcast accountsChanged to all tabs, respecting per-address permissions
 async function broadcastAccountsChanged() {
-    // Clear non-remembered approvals on address switch
-    for (const key of Object.keys(connectedSites)) {
-        delete connectedSites[key];
-    }
     // Reject and close any pending approval popups so they don't hang. An
     // approval an attempt has already claimed is left alone entirely: it is
     // being signed and broadcast right now, and neither rejecting it to the
@@ -1251,6 +1294,10 @@ async function broadcastAccountsChanged() {
         }
     }
     resetPopupUrl();
+    // An address switch ends every connection allowed without "Remember". This
+    // waits on storage, so it comes after the pending approvals above, which
+    // are still rejected the moment the switch arrives.
+    await endConnections(() => true);
     const s = await getState();
     const activeAddress = activeAddressOf(s);
     const allowed = activeAddress ? s.allowedSites[activeAddress] || [] : [];
@@ -1261,17 +1308,24 @@ async function broadcastAccountsChanged() {
         return;
     }
     for (const tab of tabs) {
+        // The tab's URL is all the background knows of the page in it, and a
+        // page at a site's URL may have another origin: a page its server
+        // sandboxes with a Content-Security-Policy has the origin "null". So
+        // the event names the origin it was judged by, and the content script
+        // passes the address on only to a page whose own origin is that one
+        // (src/content/index.js).
         const origin = tab.url ? new URL(tab.url).origin : "";
         const hasPermission =
             activeAddress &&
             (allowed.includes(origin) ||
-                connectedSites[origin + ":" + activeAddress]);
+                (await isConnected(origin, activeAddress)));
         // Same as chainChanged above: a tab without our content script
         // rejects, and that is expected rather than a fault.
         tabsSendMessage(tab.id, {
             type: "AUTISTMASK_EVENT",
             eventName: "accountsChanged",
             data: hasPermission ? [activeAddress] : [],
+            origin,
         }).catch(() => {});
     }
 }
@@ -1457,7 +1511,14 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
         // the message carries. Firefox before 126 gives no sender.origin, so
         // the origin of sender.url is used: the frame that sent the message,
         // not the tab's page, which may be another site embedding that
-        // frame. With neither, the request is refused.
+        // frame.
+        //
+        // A site is scheme://host[:port], so a request is refused when its
+        // origin has no host, as when it has no origin at all, rather than
+        // credited to the site its URL names. The browser reports "null" for
+        // a page with an opaque origin, such as one its server sandboxes with
+        // a Content-Security-Policy, and Chrome reports "file://" for a local
+        // file.
         let trustedOrigin = sender.origin;
         if (!trustedOrigin && sender.url) {
             try {
@@ -1466,7 +1527,13 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
                 // an unparseable URL leaves the origin unknown
             }
         }
-        if (!trustedOrigin) {
+        let host = "";
+        try {
+            host = new URL(trustedOrigin).host;
+        } catch {
+            // no origin, or "null", is not a URL and so has no host
+        }
+        if (!host) {
             sendResponse({
                 error: {
                     code: 4100,
@@ -1663,7 +1730,7 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
                 if (outcome.spendApproval) {
                     settleApproval(
                         msg.id,
-                        { error: { message: outcome.error } },
+                        { error: requestError(outcome.error) },
                         { holdsClaim: true },
                     );
                 } else {
@@ -1690,7 +1757,7 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
                 const outcome = describeTxFailure(TX_STAGE_NONCE, null);
                 settleApproval(
                     msg.id,
-                    { error: { message: outcome.error } },
+                    { error: requestError(outcome.error) },
                     { holdsClaim: true },
                 );
                 sendResponse({
@@ -1723,10 +1790,13 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
                 // that says plainly it did not take the transaction:
                 // describeTxFailure() reclassifies that, and the stage it
                 // returns is the one reported.
+                //
+                // A node that refused the transaction gives the page its own
+                // code and data, whatever sentence the page is shown.
                 const outcome = describeTxFailure(TX_STAGE_BROADCAST, e);
                 settleApproval(
                     msg.id,
-                    { error: { message: outcome.error } },
+                    { error: requestError(outcome.error, nodeError(e)) },
                     { holdsClaim: true },
                 );
                 sendResponse({
@@ -1848,7 +1918,7 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
                 if (!retryable) {
                     settleApproval(
                         msg.id,
-                        { error: { message: errMsg } },
+                        { error: requestError(errMsg) },
                         { holdsClaim: true },
                     );
                 } else {
@@ -1876,41 +1946,57 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
     }
 
     // The popup removed these addresses, so no site stays connected to them.
-    // A connectedSites key is origin + ":" + address, and an origin can carry
-    // a port, so the address is what follows the last colon.
     if (msg.type === "AUTISTMASK_ADDRESSES_REMOVED") {
         const removed = Array.isArray(msg.addresses) ? msg.addresses : [];
-        for (const key of Object.keys(connectedSites)) {
+        endConnections((key) => {
             const address = key.slice(key.lastIndexOf(":") + 1);
-            if (removed.some((a) => sameAddress(a, address))) {
-                delete connectedSites[key];
-            }
-        }
+            return removed.some((a) => sameAddress(a, address));
+        }).catch((err) => {
+            log.errorf(
+                "ending the removed addresses' connections failed:",
+                err,
+            );
+        });
         return false;
     }
 
-    // Settings lists the sites connected without "Remember", which only this
-    // worker knows. The origin is what precedes the key's last colon.
+    // Settings lists the sites connected without "Remember", which only
+    // session storage holds.
     if (msg.type === "AUTISTMASK_GET_CONNECTED_SITES") {
-        sendResponse(
-            Object.keys(connectedSites).map((key) =>
-                key.slice(0, key.lastIndexOf(":")),
-            ),
-        );
-        return false;
+        sessionStorageGet(null)
+            .then((items) =>
+                Object.keys(items).map((key) =>
+                    key.slice(0, key.lastIndexOf(":")),
+                ),
+            )
+            .catch((err) => {
+                log.errorf("listing the connected sites failed:", err);
+                return [];
+            })
+            .then(sendResponse);
+        return true;
     }
 
     // Settings removed this site (msg.origin) and has already dropped its
     // remembered entries. Its connections approved without "Remember" end
     // here, under every address, and its open tabs are told it has no account.
+    // The answer goes back once they have ended, and Settings waits for it
+    // before it lists the connected sites again.
     if (msg.type === "AUTISTMASK_REMOVE_SITE") {
-        for (const key of Object.keys(connectedSites)) {
-            if (key.slice(0, key.lastIndexOf(":")) === msg.origin) {
-                delete connectedSites[key];
-            }
-        }
-        broadcastSiteRemoved(msg.origin);
-        return false;
+        endConnections(
+            (key) => key.slice(0, key.lastIndexOf(":")) === msg.origin,
+        )
+            .catch((err) => {
+                log.errorf(
+                    "ending the removed site's connections failed:",
+                    err,
+                );
+            })
+            .then(() => {
+                broadcastSiteRemoved(msg.origin);
+                sendResponse(null);
+            });
+        return true;
     }
 
     // Settings switched the network and has saved it. Open tabs are told the

src/content/index.js

@@ -49,14 +49,23 @@ window.addEventListener("message", (event) => {
 
 // Listen for events pushed from the background (e.g. accountsChanged)
 runtimeApi().onMessage.addListener((msg) => {
-    if (msg.type === "AUTISTMASK_EVENT") {
-        window.postMessage(
-            {
-                type: "AUTISTMASK_EVENT",
-                eventName: msg.eventName,
-                data: msg.data,
-            },
-            "*",
-        );
+    if (msg.type !== "AUTISTMASK_EVENT") return;
+    // The background chooses the addresses in accountsChanged for the site
+    // at the origin the event names, which is the origin of the tab's URL.
+    // This page hears them only when its own origin is that one. A page whose
+    // origin has no host is not a site: one its server sandboxes with a
+    // Content-Security-Policy has the origin "null" whatever its URL, and is
+    // told no address, as its requests are refused.
+    let data = msg.data;
+    if (msg.eventName === "accountsChanged" && msg.origin !== window.origin) {
+        data = [];
     }
+    window.postMessage(
+        {
+            type: "AUTISTMASK_EVENT",
+            eventName: msg.eventName,
+            data,
+        },
+        "*",
+    );
 });

src/popup/index.js

@@ -21,6 +21,12 @@ const {
     goBack,
 } = require("./views/helpers");
 const { applyTheme } = require("./theme");
+const {
+    tabsGetCurrent,
+    tabsGetZoom,
+    windowsGetCurrent,
+    windowsUpdate,
+} = require("../shared/browserApi");
 // Renders a view the popup lands on without having navigated to it forward:
 // on restore here, and on Back. Only the views that can be fully re-rendered
 // from persisted state (RESTORABLE_VIEWS, src/shared/restorableViews.js) go
@@ -163,6 +169,40 @@ function fallbackView() {
     showView("main");
 }
 
+// The background opens the approval window as wide as the page, but the
+// browser counts the window's frame in that width, and a screen taller than
+// the window takes a vertical scrollbar out of it too. So once the screen is
+// up, the window is widened by however far the page would scroll sideways.
+// That distance is in page pixels and the window's width in screen pixels:
+// at 150% zoom one page pixel is 1.5 screen pixels. The zoom is read for this
+// page's own tab, because asked without a tab id Firefox answers for the
+// window focused last. Firefox draws some zoom steps a little larger than the
+// zoom it reports, 170% among them, so once the page has its new width (its
+// resize event) it is measured again, and the window widened again while the
+// page still falls short, three times at most. A window that cannot grow sends
+// no resize event, and the page stops there. The connection prompt can also
+// show in the toolbar popup, whose window is the user's browser window; that
+// one is left alone.
+async function widenApprovalWindow() {
+    const page = document.documentElement;
+    if (page.scrollWidth <= page.clientWidth) return;
+    const win = await windowsGetCurrent();
+    if (win.type !== "popup") return;
+    const tab = await tabsGetCurrent();
+    const zoom = await tabsGetZoom(tab.id);
+    let width = win.width;
+    for (let tries = 0; tries < 3; tries++) {
+        const sideways = page.scrollWidth - page.clientWidth;
+        if (sideways <= 0) return;
+        width += Math.ceil(sideways * zoom);
+        const resized = new Promise((resolve) =>
+            window.addEventListener("resize", resolve, { once: true }),
+        );
+        await windowsUpdate(win.id, { width });
+        await resized;
+    }
+}
+
 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
@@ -239,8 +279,8 @@ async function init() {
         // the run on both harnesses (Playwright `pageerror`, and the Firefox
         // driver's console-service drain), so nothing is lost by leaving it
         // on that path. show() puts the approval's own screen up once the
-        // background has described it.
-        approval.show(approvalId);
+        // background has described it; the window is widened to fit it then.
+        approval.show(approvalId).then(widenApprovalWindow);
         return;
     }
 

src/popup/views/addWallet.js

@@ -20,6 +20,7 @@ const {
 const { encryptWithPassword } = require("../../shared/vault");
 const { state, saveState } = require("../../shared/state");
 const { scanForAddresses } = require("../../shared/balances");
+const { notify } = require("../../shared/browserApi");
 
 /**
  * Check if an address already exists in ANY wallet (hd, xprv, or key).
@@ -194,6 +195,9 @@ async function importMnemonic(ctx) {
     };
     state.wallets.push(wallet);
     state.hasWallet = true;
+    if (state.activeAddress === null) {
+        state.activeAddress = firstAddress;
+    }
     await saveState();
     clearViewStack();
     ctx.renderWalletList();
@@ -215,8 +219,16 @@ async function importMnemonic(ctx) {
             tokenBalances: [],
         }));
         wallet.nextIndex = scan.nextIndex;
+        // The new list leaves out the first address when the scan found it
+        // unused. If it was the active one, the new list's first takes over,
+        // and the background is told as when the user picks one on Home.
+        const activeMoved =
+            state.activeAddress === firstAddress &&
+            wallet.addresses[0].address !== firstAddress;
+        if (activeMoved) state.activeAddress = wallet.addresses[0].address;
         await saveState();
         ctx.renderWalletList();
+        if (activeMoved) notify({ type: "AUTISTMASK_ACTIVE_CHANGED" });
         showFlash("Found " + scan.addresses.length + " addresses.");
     } else {
         showFlash("Ready.", 1000);
@@ -254,6 +266,9 @@ async function importPrivateKey(ctx) {
         addresses: [{ address: addr, balance: "0.0000", tokenBalances: [] }],
     });
     state.hasWallet = true;
+    if (state.activeAddress === null) {
+        state.activeAddress = addr;
+    }
     await saveState();
     clearViewStack();
     ctx.renderWalletList();
@@ -315,6 +330,9 @@ async function importXprvKey(ctx) {
     };
     state.wallets.push(wallet);
     state.hasWallet = true;
+    if (state.activeAddress === null) {
+        state.activeAddress = firstAddress;
+    }
     await saveState();
     clearViewStack();
     ctx.renderWalletList();
@@ -336,8 +354,15 @@ async function importXprvKey(ctx) {
             tokenBalances: [],
         }));
         wallet.nextIndex = scan.nextIndex;
+        // As for a recovery phrase: an active first address the scan left
+        // out gives way to the new list's first.
+        const activeMoved =
+            state.activeAddress === firstAddress &&
+            wallet.addresses[0].address !== firstAddress;
+        if (activeMoved) state.activeAddress = wallet.addresses[0].address;
         await saveState();
         ctx.renderWalletList();
+        if (activeMoved) notify({ type: "AUTISTMASK_ACTIVE_CHANGED" });
         showFlash("Found " + scan.addresses.length + " addresses.");
     } else {
         showFlash("Ready.", 1000);

src/popup/views/confirmTx.js

@@ -278,6 +278,7 @@ function renderValidation(txInfo) {
     const { canSend, codes } = validateTransfer({
         isErc20,
         amount: txInfo.amount,
+        tokenDecimals: txInfo.tokenDecimals,
         ethBalance: txInfo.balance,
         tokenBalance: txInfo.tokenBalance,
         feeStatus,

src/popup/views/send.js

@@ -24,6 +24,7 @@ const {
 } = require("../../shared/amountDisplay");
 const {
     feeReserveWei,
+    isValidAmount,
     maxEthAmount,
     maxTokenAmount,
 } = require("../../shared/txValidation");
@@ -255,13 +256,18 @@ async function fillMaxAmount() {
     const token = state.selectedToken || $("send-token").value;
 
     if (token !== "ETH") {
-        const bal = tokenBalanceAndDecimals(addr, token).tokenBalance;
+        const { tokenBalance: bal, tokenDecimals } = tokenBalanceAndDecimals(
+            addr,
+            token,
+        );
         if (bal == null) {
             showFlash("This token's balance is unknown.");
             return;
         }
         const amount = maxTokenAmount(bal);
-        if (!(parseFloat(amount) > 0)) {
+        // The balance is stored at the token's own decimal places and cut to
+        // 18 above, so the only balance this refuses is zero.
+        if (!isValidAmount(amount, tokenDecimals)) {
             showFlash("This token's balance is zero.");
             return;
         }
@@ -367,7 +373,28 @@ function init(_ctx) {
             );
             return;
         }
-        if (!amount || isNaN(parseFloat(amount)) || parseFloat(amount) <= 0) {
+
+        const token = state.selectedToken || $("send-token").value;
+        const addr = currentAddress();
+
+        let tokenSymbol = null;
+        let tokenBalance = null;
+        let tokenDecimals = null;
+        if (token !== "ETH") {
+            tokenSymbol = resolveSymbol(
+                token,
+                addr.tokenBalances,
+                state.trackedTokens,
+            );
+            ({ tokenBalance, tokenDecimals } = tokenBalanceAndDecimals(
+                addr,
+                token,
+            ));
+        }
+
+        // The confirmation screen's own amount check, so it is never shown
+        // an amount it would refuse.
+        if (!isValidAmount(amount, tokenDecimals)) {
             showFlash("Please enter a valid amount.");
             return;
         }
@@ -391,24 +418,6 @@ function init(_ctx) {
             }
         }
 
-        const token = state.selectedToken || $("send-token").value;
-        const addr = currentAddress();
-
-        let tokenSymbol = null;
-        let tokenBalance = null;
-        let tokenDecimals = null;
-        if (token !== "ETH") {
-            tokenSymbol = resolveSymbol(
-                token,
-                addr.tokenBalances,
-                state.trackedTokens,
-            );
-            ({ tokenBalance, tokenDecimals } = tokenBalanceAndDecimals(
-                addr,
-                token,
-            ));
-        }
-
         ctx.showConfirmTx({
             from: addr.address,
             to: resolvedTo,

src/popup/views/settings.js

@@ -76,11 +76,13 @@ function forgetOrigin(siteMap, origin) {
 
 // Removing a site from Allowed Sites or Connected Sites disconnects it: it is
 // no longer allowed under any address, and the background ends its
-// connections approved without "Remember" and tells its open tabs.
+// connections approved without "Remember" and tells its open tabs. The
+// background answers once those have ended, so the lists drawn after it no
+// longer show the site.
 async function removeAllowedSite(origin) {
     forgetOrigin(state.allowedSites, origin);
     await saveState();
-    notify({ type: "AUTISTMASK_REMOVE_SITE", origin });
+    await sendMessage({ type: "AUTISTMASK_REMOVE_SITE", origin });
     await renderSiteLists();
 }
 
@@ -230,8 +232,8 @@ async function renderSiteLists() {
         Object.values(state.deniedSites).flat(),
         removeDeniedSite,
     );
-    // Sites allowed without "Remember" are held only by the background, in
-    // memory, so it is asked for them.
+    // Sites allowed without "Remember" are held only in session storage, which
+    // the background keeps, so it is asked for them.
     renderSiteList(
         "settings-connected-sites",
         await sendMessage({ type: "AUTISTMASK_GET_CONNECTED_SITES" }),

src/shared/approvalTx.js

@@ -41,6 +41,7 @@ const {
     ALLOWED_TX_TYPES,
     SERIALIZED_FIELDS,
     assertWithinCeilings,
+    nodeError,
 } = require("./approvalVerify");
 
 // How long the population may take before the request is failed back to the
@@ -72,15 +73,27 @@ const REQUEST_FIELDS = [
     "type",
 ];
 
+// EIP-1474's code for invalid parameters: what the page is given when the
+// site asked for a transaction this wallet refuses as it was asked for.
+const INVALID_PARAMS_CODE = -32602;
+
+// Why no approval can be raised. The message is the sentence the page is
+// shown. `code` and `data` are the JSON-RPC ones it is given with it: the
+// node's own, unchanged, when the node refused the transaction, so a site can
+// decode a revert; INVALID_PARAMS_CODE when the site's request is refused;
+// none when the failure is the wallet's own, which the background answers as
+// an internal error.
 class ApprovalPrepareError extends Error {
-    constructor(message) {
+    constructor(message, code, data) {
         super(message);
         this.name = "ApprovalPrepareError";
+        if (code !== undefined) this.code = code;
+        if (data !== undefined) this.data = data;
     }
 }
 
-function fail(message) {
-    return new ApprovalPrepareError(message);
+function fail(message, code, data) {
+    return new ApprovalPrepareError(message, code, data);
 }
 
 function present(v) {
@@ -134,6 +147,7 @@ function requestFrom(txParams, from) {
         ) {
             throw fail(
                 "The site asked for two different gas limits for this transaction.",
+                INVALID_PARAMS_CODE,
             );
         }
         request.gasLimit = txParams.gas;
@@ -144,6 +158,7 @@ function requestFrom(txParams, from) {
     ) {
         throw fail(
             "The site asked for a transaction of a type this wallet does not sign.",
+            INVALID_PARAMS_CODE,
         );
     }
     return request;
@@ -228,6 +243,9 @@ async function prepareApprovalTx(provider, from, txParams) {
         );
     } catch (e) {
         if (e instanceof ApprovalPrepareError) throw e;
+        // A refusal from the node, such as a reverting gas estimate, keeps
+        // the node's code and revert data.
+        const fromNode = nodeError(e);
         throw fail(
             sentence(
                 "The transaction could not be prepared: " +
@@ -235,6 +253,8 @@ async function prepareApprovalTx(provider, from, txParams) {
                         e.message ||
                         "the network did not answer"),
             ),
+            fromNode?.code,
+            fromNode?.data,
         );
     }
 

src/shared/approvalVerify.js

@@ -746,6 +746,15 @@ function errorText(err) {
     return "The transaction could not be sent.";
 }
 
+// The JSON-RPC error object the node answered with, `{ code, message, data }`,
+// out of the error ethers threw for that answer. ethers keeps it under
+// `info.error`, or under `error` when it could not classify it. Null when
+// there is none, as for a node that could not be reached.
+function nodeError(err) {
+    if (!err || typeof err !== "object") return null;
+    return err.error || (err.info && err.info.error) || null;
+}
+
 // Every string a failure might carry its reason in. ethers reports the node's
 // own words in `shortMessage`, but a JSON-RPC error it could not classify is
 // nested under `error` or `info.error` with the node's message intact, and the
@@ -757,7 +766,7 @@ function failureTexts(err) {
     for (const text of [err.shortMessage, err.message, err.reason]) {
         if (text) texts.push(String(text));
     }
-    const nested = err.error || (err.info && err.info.error);
+    const nested = nodeError(err);
     if (nested && nested.message) texts.push(String(nested.message));
     return texts;
 }
@@ -891,6 +900,7 @@ module.exports = {
     assertWithinCeilings,
     sameAddress,
     failureIsRetryable,
+    nodeError,
     isNonceCollision,
     describeTxFailure,
     describeSigningFailure,

src/shared/browserApi.js

@@ -174,9 +174,9 @@ function notify(message) {
 // default: resolving {} would make an existing wallet read back as no wallet,
 // and resolving a no-op write would discard the user's state with nothing
 // logged. A caller that wants to degrade takes storageLocal() directly.
-function storageUnavailable(method) {
+function storageUnavailable(area, method) {
     return Promise.reject(
-        new Error("extension storage.local is not available: " + method),
+        new Error("extension storage." + area + " is not available: " + method),
     );
 }
 
@@ -187,7 +187,7 @@ function storageUnavailable(method) {
  */
 function storageGet(keys) {
     const storage = storageLocal();
-    if (!storage) return storageUnavailable("get");
+    if (!storage) return storageUnavailable("local", "get");
     return Promise.resolve(storage.get(keys));
 }
 
@@ -198,7 +198,7 @@ function storageGet(keys) {
  */
 function storageSet(items) {
     const storage = storageLocal();
-    if (!storage) return storageUnavailable("set");
+    if (!storage) return storageUnavailable("local", "set");
     return Promise.resolve(storage.set(items));
 }
 
@@ -215,7 +215,55 @@ function storageSet(items) {
  */
 function storageRemove(keys) {
     const storage = storageLocal();
-    if (!storage) return storageUnavailable("remove");
+    if (!storage) return storageUnavailable("local", "remove");
+    return Promise.resolve(storage.remove(keys));
+}
+
+// `storage.session`, the browser's session storage: what is kept there lasts
+// until the browser closes. It survives the background worker being stopped
+// and started again, which module-level variables do not (README, Background
+// scheduling). The background keeps the connections allowed without
+// "Remember" there; see src/background/index.js. Firefox has it from version
+// 115, the minimum manifest/firefox.json declares.
+//
+// The three below reject where it is absent, as the three above do where
+// `storage.local` is: a write that silently did nothing would tell a site it
+// is connected and then refuse its next request.
+function storageSession() {
+    const storage = namespaceMember("storage");
+    return (storage && storage.session) || null;
+}
+
+/**
+ * @param {string|string[]|null} keys null for every item.
+ * @returns {Promise<Object>} the stored items.
+ * @throws rejects where `storage.session` is absent.
+ */
+function sessionStorageGet(keys) {
+    const storage = storageSession();
+    if (!storage) return storageUnavailable("session", "get");
+    return Promise.resolve(storage.get(keys));
+}
+
+/**
+ * @param {Object} items
+ * @returns {Promise<void>}
+ * @throws rejects where `storage.session` is absent.
+ */
+function sessionStorageSet(items) {
+    const storage = storageSession();
+    if (!storage) return storageUnavailable("session", "set");
+    return Promise.resolve(storage.set(items));
+}
+
+/**
+ * @param {string|string[]} keys
+ * @returns {Promise<void>}
+ * @throws rejects where `storage.session` is absent.
+ */
+function sessionStorageRemove(keys) {
+    const storage = storageSession();
+    if (!storage) return storageUnavailable("session", "remove");
     return Promise.resolve(storage.remove(keys));
 }
 
@@ -243,6 +291,22 @@ function tabsSendMessage(tabId, message) {
     return invoke(tabsApi(), "sendMessage", tabId, message);
 }
 
+/**
+ * @returns {Promise<Object|undefined>} the tab the calling page is in, or
+ *     undefined for a page not in a tab, such as the toolbar popup.
+ */
+function tabsGetCurrent() {
+    return invoke(tabsApi(), "getCurrent");
+}
+
+/**
+ * @param {number} tabId
+ * @returns {Promise<number>} that tab's zoom: 1.5 at 150%.
+ */
+function tabsGetZoom(tabId) {
+    return invoke(tabsApi(), "getZoom", tabId);
+}
+
 /**
  * @param {Object} createData
  * @returns {Promise<Object>} the created window.
@@ -258,6 +322,22 @@ function windowsGetLastFocused() {
     return invoke(windowsApi(), "getLastFocused");
 }
 
+/**
+ * @returns {Promise<Object>} the window the calling page is in.
+ */
+function windowsGetCurrent() {
+    return invoke(windowsApi(), "getCurrent");
+}
+
+/**
+ * @param {number} windowId
+ * @param {Object} updateInfo
+ * @returns {Promise<Object>} the updated window.
+ */
+function windowsUpdate(windowId, updateInfo) {
+    return invoke(windowsApi(), "update", windowId, updateInfo);
+}
+
 /**
  * @param {number} windowId
  * @returns {Promise<void>}
@@ -275,15 +355,22 @@ module.exports = {
     notify,
     runtimeApi,
     sendMessage,
+    sessionStorageGet,
+    sessionStorageRemove,
+    sessionStorageSet,
     storageGet,
     storageLocal,
     storageRemove,
     storageSet,
     tabsApi,
+    tabsGetCurrent,
+    tabsGetZoom,
     tabsQuery,
     tabsSendMessage,
     windowsApi,
     windowsCreate,
+    windowsGetCurrent,
     windowsGetLastFocused,
     windowsRemove,
+    windowsUpdate,
 };

src/shared/txValidation.js

@@ -1,4 +1,5 @@
-// Balance arithmetic for the Send and transaction confirmation screens.
+// The amount check and balance arithmetic for the Send and transaction
+// confirmation screens.
 //
 // Pure: no DOM, no network, no state. Everything is exact integer math on
 // 18-decimal fixed point (wei for ETH), so it can be unit tested directly
@@ -20,7 +21,7 @@ const FEE_KNOWN = "known";
 const FEE_UNAVAILABLE = "unavailable";
 
 const CODES = {
-    // The amount is not a non-negative number we can do exact arithmetic on.
+    // The amount is one isValidAmount() refuses.
     AMOUNT_INVALID: "amount-invalid",
     // ERC-20: the token amount exceeds the token balance.
     INSUFFICIENT_TOKEN: "insufficient-token",
@@ -87,6 +88,27 @@ function toFixedPoint(value) {
     }
 }
 
+// Whether `amount` can be sent: a number above zero, written as digits with
+// at most one decimal point ("0.5", "12", ".5"), with nothing but zeros after
+// the token's last decimal place, `tokenDecimals`, and nothing but zeros after
+// the 18th, the places the arithmetic here works in, which are ETH's. ETH, and
+// a token whose decimal places are unknown, pass null and are held to the 18
+// (the confirmation screen refuses to send such a token anyway). Zeros past
+// those places are accepted because parseUnits() drops them here and again
+// when the transfer is encoded, so "1.0000000" of a 6-place token is exactly
+// 1 everywhere. Refuses "1e-3", "1abc", "0" and "-1". The Send screen checks
+// it before the confirmation screen opens, and validateTransfer() checks it
+// again there.
+function isValidAmount(amount, tokenDecimals = null) {
+    if (typeof amount !== "string") return false;
+    const places = Math.min(tokenDecimals ?? SCALE_DECIMALS, SCALE_DECIMALS);
+    try {
+        return parseUnits(amount.trim(), places) > 0n;
+    } catch {
+        return false;
+    }
+}
+
 // The most ETH a send can carry: the exact balance minus the fee reserve from
 // feeReserveWei(), as a decimal string, so validateTransfer() passes it with
 // exactly that reserve left behind. `ethBalance` is the exact decimal string
@@ -112,9 +134,11 @@ function maxTokenAmount(tokenBalance) {
 // Validate a pending transfer against the balances that must cover it.
 //
 //   isErc20      — token transfer rather than a native ETH transfer
-//   amount       — human decimal string being sent, non-negative. Anything
-//                  else, a negative value included, is an unusable amount
+//   amount       — human decimal string being sent. One isValidAmount()
+//                  refuses, a negative value included, is an unusable amount
 //                  rather than an amount that passes every comparison.
+//   tokenDecimals — ERC-20: the token's decimal places, or null when they
+//                  are unknown. Passed to isValidAmount().
 //   ethBalance   — human decimal string, the sender's ETH balance
 //   tokenBalance — human decimal string, the sender's token balance
 //   feeStatus    — FEE_PENDING, FEE_KNOWN or FEE_UNAVAILABLE. Anything else
@@ -128,6 +152,7 @@ function maxTokenAmount(tokenBalance) {
 function validateTransfer({
     isErc20 = false,
     amount,
+    tokenDecimals = null,
     ethBalance,
     tokenBalance,
     feeStatus = FEE_PENDING,
@@ -135,17 +160,17 @@ function validateTransfer({
 } = {}) {
     const codes = [];
 
-    const amountFp = toFixedPoint(amount);
-    const ethFp = toFixedPoint(ethBalance) ?? 0n;
-
-    // A negative amount parses to a valid bigint, so every comparison below
-    // is trivially false and the send clears the screen — then dies at encode
-    // time in parseEther(). Unusable, on the same footing as a malformed fee.
-    if (amountFp === null || amountFp < 0n) {
+    // An amount refused here never reaches the comparisons below: a negative
+    // one would pass every one of them, then die at encode time in
+    // parseEther().
+    if (!isValidAmount(amount, isErc20 ? tokenDecimals : null)) {
         codes.push(CODES.AMOUNT_INVALID);
         return { canSend: false, codes };
     }
 
+    const amountFp = toFixedPoint(amount);
+    const ethFp = toFixedPoint(ethBalance) ?? 0n;
+
     // Fail closed. Anything that is not a usable fee under a recognised
     // status — a malformed feeWei, or a status this module does not know —
     // is an unavailable estimate, never a fee of zero. Every such input errs
@@ -195,6 +220,7 @@ module.exports = {
     SCALE_DECIMALS,
     feeReserveWei,
     feeEstimateWei,
+    isValidAmount,
     maxEthAmount,
     maxTokenAmount,
     toFixedPoint,

src/shared/uniswap.js

@@ -290,7 +290,9 @@ const V4_SWAP_EXACT_IN = 0x07;
 const V4_SWAP_EXACT_OUT_SINGLE = 0x08;
 const V4_SWAP_EXACT_OUT = 0x09;
 const V4_SETTLE = 0x0b;
+const V4_SETTLE_ALL = 0x0c;
 const V4_TAKE = 0x0e;
+const V4_TAKE_ALL = 0x0f;
 
 // 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
@@ -318,10 +320,132 @@ function decodeExactly(types, data) {
     return decoded;
 }
 
+// Decode one V4 swap action's parameters into the currency it spends
+// (`tokenIn`), the currency it buys (`tokenOut`) and, for an exact-in action,
+// its `amountIn` and `amountOutMin`. The exact-out actions decode no amounts.
+// A field the action does not state is null. Throws when the parameters are
+// not in the deployed shape (see decodeExactly()).
+function decodeV4SwapAction(actionId, param) {
+    if (actionId === V4_SWAP_EXACT_IN) {
+        // ExactInputParams: (address currencyIn,
+        //   tuple(address,uint24,int24,address,bytes)[] path,
+        //   uint128 amountIn, uint128 amountOutMin)
+        const s = decodeExactly(
+            [
+                "tuple(address,tuple(address,uint24,int24,address,bytes)[],uint128,uint128)",
+            ],
+            param,
+        );
+        const path = s[0][1];
+        return {
+            tokenIn: s[0][0],
+            tokenOut: path.length > 0 ? path[path.length - 1][0] : null,
+            amountIn: v4ExactInAmount(s[0][2]),
+            amountOutMin: s[0][3],
+        };
+    }
+    if (actionId === V4_SWAP_EXACT_IN_SINGLE) {
+        // ExactInputSingleParams: (tuple(address,address,uint24,int24,address) poolKey,
+        //   bool zeroForOne, uint128 amountIn, uint128 amountOutMin, bytes hookData)
+        const s = decodeExactly(
+            [
+                "tuple(tuple(address,address,uint24,int24,address),bool,uint128,uint128,bytes)",
+            ],
+            param,
+        );
+        const poolKey = s[0][0];
+        const zeroForOne = s[0][1];
+        return {
+            tokenIn: zeroForOne ? poolKey[0] : poolKey[1],
+            tokenOut: zeroForOne ? poolKey[1] : poolKey[0],
+            amountIn: v4ExactInAmount(s[0][2]),
+            amountOutMin: s[0][3],
+        };
+    }
+    if (actionId === V4_SWAP_EXACT_OUT) {
+        // ExactOutputParams: (address currencyOut,
+        //   tuple(address,uint24,int24,address,bytes)[] path,
+        //   uint128 amountOut, uint128 amountInMaximum)
+        const s = decodeExactly(
+            [
+                "tuple(address,tuple(address,uint24,int24,address,bytes)[],uint128,uint128)",
+            ],
+            param,
+        );
+        // The router works through the path from its last entry back to its
+        // first, starting from currencyOut, so the first entry is what the
+        // action spends.
+        const path = s[0][1];
+        return {
+            tokenIn: path.length > 0 ? path[0][0] : null,
+            tokenOut: s[0][0],
+            amountIn: null,
+            amountOutMin: null,
+        };
+    }
+    // V4_SWAP_EXACT_OUT_SINGLE. ExactOutputSingleParams: (poolKey as above,
+    //   bool zeroForOne, uint128 amountOut, uint128 amountInMaximum,
+    //   bytes hookData)
+    const s = decodeExactly(
+        [
+            "tuple(tuple(address,address,uint24,int24,address),bool,uint128,uint128,bytes)",
+        ],
+        param,
+    );
+    const poolKey = s[0][0];
+    const zeroForOne = s[0][1];
+    return {
+        tokenIn: zeroForOne ? poolKey[0] : poolKey[1],
+        tokenOut: zeroForOne ? poolKey[1] : poolKey[0],
+        amountIn: null,
+        amountOutMin: null,
+    };
+}
+
+// The currencies in `list` that `other` does not hold, each listed once.
+function currenciesNotIn(list, other) {
+    return [...new Set(list.filter((c) => !other.includes(c)))];
+}
+
+// The amount that the swap actions on one side of a V4 step state together:
+// the one action's own amount, or the sum when there are several and each
+// states a quantity. Exact-out actions state none here, and the open delta is
+// not a quantity. Otherwise null.
+function totalAmount(amounts) {
+    if (amounts.length === 1) return amounts[0];
+    if (amounts.length === 0) return null;
+    if (!amounts.every((a) => typeof a === "bigint")) return null;
+    return amounts.reduce((sum, a) => sum + a, 0n);
+}
+
 // 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,
-// and swap amounts from the swap sub-actions.
+// The input is ABI-encoded as (bytes actions, bytes[] params). Each swap
+// action gives the currency it spends and the currency it buys (see
+// decodeV4SwapAction()). The step's sides then follow three rules:
+//
+// 1. Token In is the currency SETTLE or SETTLE_ALL names; otherwise the one
+//    currency that some swap action spends and none buys. Token Out is the
+//    currency TAKE or TAKE_ALL names; otherwise the one currency that some
+//    swap action buys and none spends. If there is not exactly one such
+//    currency, that side is unknown.
+// 2. Amount is the amountIn of the swap action that spends Token In. If
+//    several exact-in actions spend it, each with a stated amount, it is
+//    their sum; in any other case there is none. Min. received is the same
+//    for amountOutMin and the actions that buy Token Out.
+// 3. If any swap action in the step cannot be read, only SETTLE, SETTLE_ALL,
+//    TAKE and TAKE_ALL name the sides, and there is no Amount or Min.
+//    received.
+//
+// A currency a swap action does not name, such as what an exact-in action
+// with an empty path buys, is null and counts in rules 1 and 2 as a currency
+// like any other: a step of only that action has an unknown Token Out and
+// the action's amountOutMin as Min. received.
+//
+// `hasSwapAction` is true when the step has a swap action, read or not.
+// decode() then sets both sides from this step, a side these rules leave
+// unknown included, so no other step's token or figure shows for it. A step
+// with no swap action sets only the sides SETTLE, SETTLE_ALL, TAKE and
+// TAKE_ALL name.
 function decodeV4Swap(input) {
     try {
         const d = coder.decode(["bytes", "bytes[]"], input);
@@ -330,11 +454,12 @@ function decodeV4Swap(input) {
 
         let settleToken = null;
         let takeToken = null;
-        let amountIn = null;
-        let amountOutMin = null;
+        // The step's swap actions that could be read, as decodeV4SwapAction()
+        // reads them.
+        const swaps = [];
         // Set when a swap action's parameters are not in the deployed shape
-        // (see decodeExactly()), so nothing was read from that action. SETTLE
-        // and TAKE may still name both currencies.
+        // (see decodeExactly()), so nothing was read from that action. SETTLE,
+        // SETTLE_ALL, TAKE and TAKE_ALL may still name both currencies.
         let swapUndecoded = false;
 
         for (let i = 0; i < actions.length; i++) {
@@ -347,6 +472,10 @@ function decodeV4Swap(input) {
                         params[i],
                     );
                     settleToken = s[0];
+                } else if (actionId === V4_SETTLE_ALL) {
+                    // SETTLE_ALL: (address currency, uint256 maxAmount)
+                    const s = coder.decode(["address", "uint256"], params[i]);
+                    settleToken = s[0];
                 } else if (actionId === V4_TAKE) {
                     // TAKE: (address currency, address recipient, uint256 amount)
                     const t = coder.decode(
@@ -354,107 +483,20 @@ function decodeV4Swap(input) {
                         params[i],
                     );
                     takeToken = t[0];
+                } else if (actionId === V4_TAKE_ALL) {
+                    // TAKE_ALL: (address currency, uint256 minAmount)
+                    const t = coder.decode(["address", "uint256"], params[i]);
+                    takeToken = t[0];
                 } else if (
+                    actionId === V4_SWAP_EXACT_IN_SINGLE ||
                     actionId === V4_SWAP_EXACT_IN ||
-                    actionId === V4_SWAP_EXACT_IN_SINGLE
+                    actionId === V4_SWAP_EXACT_OUT_SINGLE ||
+                    actionId === V4_SWAP_EXACT_OUT
                 ) {
-                    // Extract amounts from exact-in swap actions
-                    if (actionId === V4_SWAP_EXACT_IN) {
-                        // ExactInputParams: (address currencyIn,
-                        //   tuple(address,uint24,int24,address,bytes)[] path,
-                        //   uint128 amountIn, uint128 amountOutMin)
-                        try {
-                            const s = decodeExactly(
-                                [
-                                    "tuple(address,tuple(address,uint24,int24,address,bytes)[],uint128,uint128)",
-                                ],
-                                params[i],
-                            );
-                            if (!present(settleToken)) settleToken = s[0][0];
-                            const path = s[0][1];
-                            if (path.length > 0 && !present(takeToken)) {
-                                takeToken = path[path.length - 1][0];
-                            }
-                            if (!present(amountIn)) {
-                                amountIn = v4ExactInAmount(s[0][2]);
-                            }
-                            if (!present(amountOutMin)) {
-                                amountOutMin = s[0][3];
-                            }
-                        } catch {
-                            swapUndecoded = true;
-                        }
-                    } else {
-                        // ExactInputSingleParams: (tuple(address,address,uint24,int24,address) poolKey,
-                        //   bool zeroForOne, uint128 amountIn, uint128 amountOutMin, bytes hookData)
-                        try {
-                            const s = decodeExactly(
-                                [
-                                    "tuple(tuple(address,address,uint24,int24,address),bool,uint128,uint128,bytes)",
-                                ],
-                                params[i],
-                            );
-                            const poolKey = s[0][0];
-                            const zeroForOne = s[0][1];
-                            if (!present(settleToken))
-                                settleToken = zeroForOne
-                                    ? poolKey[0]
-                                    : poolKey[1];
-                            if (!present(takeToken))
-                                takeToken = zeroForOne
-                                    ? poolKey[1]
-                                    : poolKey[0];
-                            if (!present(amountIn)) {
-                                amountIn = v4ExactInAmount(s[0][2]);
-                            }
-                            if (!present(amountOutMin)) {
-                                amountOutMin = s[0][3];
-                            }
-                        } catch {
-                            swapUndecoded = true;
-                        }
-                    }
-                } else if (
-                    actionId === V4_SWAP_EXACT_OUT ||
-                    actionId === V4_SWAP_EXACT_OUT_SINGLE
-                ) {
-                    if (actionId === V4_SWAP_EXACT_OUT) {
-                        try {
-                            const s = decodeExactly(
-                                [
-                                    "tuple(address,tuple(address,uint24,int24,address,bytes)[],uint128,uint128)",
-                                ],
-                                params[i],
-                            );
-                            if (!present(takeToken)) takeToken = s[0][0];
-                            const path = s[0][1];
-                            if (path.length > 0 && !present(settleToken)) {
-                                settleToken = path[path.length - 1][0];
-                            }
-                        } catch {
-                            swapUndecoded = true;
-                        }
-                    } else {
-                        try {
-                            const s = decodeExactly(
-                                [
-                                    "tuple(tuple(address,address,uint24,int24,address),bool,uint128,uint128,bytes)",
-                                ],
-                                params[i],
-                            );
-                            const poolKey = s[0][0];
-                            const zeroForOne = s[0][1];
-                            if (!present(settleToken))
-                                settleToken = zeroForOne
-                                    ? poolKey[0]
-                                    : poolKey[1];
-                            if (!present(takeToken))
-                                takeToken = zeroForOne
-                                    ? poolKey[1]
-                                    : poolKey[0];
-                        } catch {
-                            swapUndecoded = true;
-                        }
+                    try {
+                        swaps.push(decodeV4SwapAction(actionId, params[i]));
+                    } catch {
+                        swapUndecoded = true;
                     }
                 }
             } catch {
@@ -462,12 +504,54 @@ function decodeV4Swap(input) {
             }
         }
 
+        // Rule 3.
+        if (swapUndecoded) {
+            return {
+                tokenIn: settleToken,
+                tokenOut: takeToken,
+                amountIn: null,
+                amountOutMin: null,
+                swapUndecoded,
+                hasSwapAction: true,
+            };
+        }
+
+        const spent = swaps.map((s) => s.tokenIn);
+        const bought = swaps.map((s) => s.tokenOut);
+
+        // Rules 1 and 2 for Token In.
+        let tokenIn = null;
+        let amountIn = null;
+        const spentOnly = currenciesNotIn(spent, bought);
+        if (present(settleToken) || spentOnly.length === 1) {
+            tokenIn = present(settleToken) ? settleToken : spentOnly[0];
+            amountIn = totalAmount(
+                swaps
+                    .filter((s) => s.tokenIn === tokenIn)
+                    .map((s) => s.amountIn),
+            );
+        }
+
+        // Rules 1 and 2 for Token Out.
+        let tokenOut = null;
+        let amountOutMin = null;
+        const boughtOnly = currenciesNotIn(bought, spent);
+        if (present(takeToken) || boughtOnly.length === 1) {
+            tokenOut = present(takeToken) ? takeToken : boughtOnly[0];
+            amountOutMin = totalAmount(
+                swaps
+                    .filter((s) => s.tokenOut === tokenOut)
+                    .map((s) => s.amountOutMin),
+            );
+        }
+
         return {
-            tokenIn: settleToken,
-            tokenOut: takeToken,
+            tokenIn,
+            tokenOut,
             amountIn,
             amountOutMin,
             swapUndecoded,
+            hasSwapAction: swaps.length > 0,
         };
     } catch {
         return null;
@@ -491,6 +575,7 @@ function decode(data, toAddress, sources) {
         let inputEstablished = false;
         let outputToken = null;
         let minOutput = null;
+        let outputEstablished = false;
         let hasUnwrapWeth = false;
         let hasV2ExactOut = false;
         let swapUndecoded = false;
@@ -526,6 +611,7 @@ function decode(data, toAddress, sources) {
             if (!present(token) && !present(amount)) return;
             outputToken = present(token) ? token : null;
             minOutput = present(amount) ? amount : null;
+            outputEstablished = true;
         };
 
         for (let i = 0; i < commandsBytes.length; i++) {
@@ -597,30 +683,33 @@ function decode(data, toAddress, sources) {
                 if (cmdId === 0x10) {
                     const v4 = decodeV4Swap(inputs[i]);
                     if (v4 && v4.swapUndecoded) {
-                        // The unread swap action named this step's currencies
-                        // and amounts, so the step is marked and still sets
-                        // both sides as a swap step does. A side its SETTLE or
-                        // TAKE did not name is set undetermined, not left to
-                        // an earlier or later step's token and figure.
+                        // A swap action of this step went unread, so the step
+                        // is marked.
                         swapUndecoded = true;
                         commandNames[i] += " (could not be decoded)";
+                    }
+                    if (v4 && v4.hasSwapAction) {
+                        // A step with a swap action sets both sides as a swap
+                        // step does, the input when no earlier step set it and
+                        // the output always, as the last swap step wins. Each
+                        // side is set as a pair, so a side decodeV4Swap() left
+                        // unknown is set unknown with no figure, rather than
+                        // left to another step's token and figure. A token
+                        // stated without a figure, or a figure without a
+                        // token, likewise never sits beside an earlier step's
+                        // other half.
                         if (!inputEstablished) {
                             setInput(v4.tokenIn, v4.amountIn);
                         }
                         outputToken = v4.tokenOut;
                         minOutput = v4.amountOutMin;
+                        outputEstablished = true;
                     } else if (v4) {
+                        // A step with no swap action sets only the sides its
+                        // SETTLE, SETTLE_ALL, TAKE or TAKE_ALL names:
+                        // setInputOnce() and setOutput() leave alone a side
+                        // whose two halves are both unstated.
                         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.
-                        // 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);
                     }
                 }
@@ -634,21 +723,19 @@ function decode(data, toAddress, sources) {
         }
 
         // Resolve token info. A null token on either side means no step named
-        // a currency for it, or a V4 step whose swap action went unread left
-        // it undetermined; tokenInfo() refuses rather than calling it ETH.
+        // a currency for it, or a V4 step with a swap action left it
+        // unknown; tokenInfo() refuses rather than calling it ETH.
         // UNWRAP_WETH turns WETH into ETH, so it makes the output ETH when the
-        // output side is WETH, or when no step set the output side. A step
-        // whose swap action went unread did set it, to undetermined. Any other
+        // output side is WETH, or when no step set the output side. A V4 step
+        // with a swap action did set it, even when it set it unknown. Any other
         // output keeps its own token and figure: a swap that buys USDC and
         // then unwraps the WETH it did not spend receives USDC.
         const outputIsWeth =
             present(outputToken) &&
             WETH_ADDRESSES.includes(outputToken.toLowerCase());
-        const outputUnset =
-            !present(outputToken) && !present(minOutput) && !swapUndecoded;
         const inInfo = tokenInfo(inputToken, sources);
         const outInfo =
-            hasUnwrapWeth && (outputIsWeth || outputUnset)
+            hasUnwrapWeth && (outputIsWeth || !outputEstablished)
                 ? { symbol: "ETH", decimals: 18, address: null }
                 : tokenInfo(outputToken, sources);
 

src/shared/walletDelete.js

@@ -14,7 +14,7 @@ function sameAddress(a, b) {
 
 // Forget every site permission held against the given addresses: the
 // remembered ones in `state`, and the connections approved without
-// "Remember", which only the background holds, in memory.
+// "Remember", which only the background holds, in session storage.
 function dropSitePermissions(state, addresses) {
     for (const addr of addresses) {
         delete state.allowedSites[addr];

tests/accountsChangedOpaqueOrigin.test.js

@@ -0,0 +1,167 @@
+// A page whose origin has no host is never told an address by accountsChanged
+// (https://git.eeqj.de/sneak/AutistMask/issues/564).
+//
+// When the user switches address, the background tells each open tab the new
+// active address if the site at the tab's URL is connected. A page at a
+// connected site's URL can still have another origin: one its server
+// sandboxes with a Content-Security-Policy has the origin "null", and every
+// request it makes is refused. Each test here switches the address in the real
+// background, takes the event it sent to a tab at the site's URL, and hands
+// that event to the real content script in a page of the given origin.
+
+const { networkById } = require("../src/shared/networks");
+const { makeStorageStub } = require("./support/storageStub");
+
+const ADDRESS = "0x66133E8ea0f5D1d612D2502a968757D1048c214a";
+const SITE = "https://dapp.example";
+
+const EXT_URL = "chrome-extension://autistmask/";
+const FROM_POPUP = { url: EXT_URL + "src/popup/index.html" };
+
+// One address, with SITE remembered as allowed for it.
+function storedProfile() {
+    const mainnet = networkById("mainnet");
+    return {
+        hasWallet: true,
+        wallets: [
+            {
+                name: "Wallet 1",
+                type: "hd",
+                addresses: [
+                    { address: ADDRESS, balance: "0", tokenBalances: [] },
+                ],
+            },
+        ],
+        activeAddress: ADDRESS,
+        networkId: "mainnet",
+        rpcUrl: mainnet.defaultRpcUrl,
+        blockscoutUrl: mainnet.defaultBlockscoutUrl,
+        allowedSites: { [ADDRESS]: [SITE] },
+        deniedSites: {},
+        trackedTokens: [],
+    };
+}
+
+async function settle() {
+    for (let i = 0; i < 50; i++) await Promise.resolve();
+}
+
+afterEach(() => {
+    delete global.chrome;
+    delete global.window;
+    jest.resetModules();
+});
+
+// The popup tells the background the active address changed, and the one
+// open tab, at SITE's URL, is sent an event. That event is returned.
+async function eventSentToSiteTab() {
+    jest.resetModules();
+    jest.doMock("../src/shared/balances", () => ({
+        getProvider: () => ({}),
+        refreshBalances: jest.fn(async () => {}),
+    }));
+    jest.doMock("../src/shared/phishingDomains", () => ({
+        isPhishingDomain: () => false,
+    }));
+    jest.doMock("../src/shared/alarms", () => ({
+        BALANCE_REFRESH_ALARM: "balance",
+        BALANCE_REFRESH_PERIOD_MINUTES: 1,
+        ensureRecurringAlarms: jest.fn(async () => {}),
+        registerAlarmHandlers: jest.fn(),
+    }));
+
+    let messageListener = null;
+    const sentToTabs = [];
+    global.chrome = {
+        storage: makeStorageStub({ autistmask: storedProfile() }),
+        runtime: {
+            getURL: (path) => EXT_URL + path,
+            onMessage: {
+                addListener: (fn) => {
+                    messageListener = fn;
+                },
+            },
+            onConnect: { addListener: () => {} },
+            getPlatformInfo: (cb) => cb({ os: "linux" }),
+            lastError: null,
+        },
+        windows: {
+            remove: (id, cb) => {
+                if (cb) cb();
+            },
+            onRemoved: { addListener: () => {} },
+        },
+        tabs: {
+            query: (q, cb) => cb([{ id: 1, url: SITE + "/app" }]),
+            sendMessage: (tabId, msg, cb) => {
+                sentToTabs.push(msg);
+                if (cb) cb();
+            },
+        },
+        action: { setPopup: () => {} },
+    };
+
+    require("../src/background/index");
+    messageListener(
+        { type: "AUTISTMASK_ACTIVE_CHANGED" },
+        FROM_POPUP,
+        () => {},
+    );
+    await settle();
+
+    expect(sentToTabs).toHaveLength(1);
+    return sentToTabs[0];
+}
+
+// The content script in a page whose origin is `pageOrigin` is handed `event`
+// from the background. What it posts to the page is returned.
+function postedToPage(event, pageOrigin) {
+    jest.resetModules();
+    let eventListener = null;
+    const posted = [];
+    global.chrome = {
+        runtime: {
+            onMessage: {
+                addListener: (fn) => {
+                    eventListener = fn;
+                },
+            },
+        },
+    };
+    global.window = {
+        origin: pageOrigin,
+        addEventListener: () => {},
+        postMessage: (data) => posted.push(data),
+    };
+
+    require("../src/content/index");
+    eventListener(event);
+
+    return posted;
+}
+
+describe("accountsChanged after an address switch, at a connected site's URL", () => {
+    test("the site's own page is told the active address", async () => {
+        const event = await eventSentToSiteTab();
+
+        expect(postedToPage(event, SITE)).toEqual([
+            {
+                type: "AUTISTMASK_EVENT",
+                eventName: "accountsChanged",
+                data: [ADDRESS],
+            },
+        ]);
+    });
+
+    test("a page whose origin has no host is told no address", async () => {
+        const event = await eventSentToSiteTab();
+
+        expect(postedToPage(event, "null")).toEqual([
+            {
+                type: "AUTISTMASK_EVENT",
+                eventName: "accountsChanged",
+                data: [],
+            },
+        ]);
+    });
+});

tests/approvalWindow.test.js

@@ -45,3 +45,132 @@ test("the approval window shows no screen until the background describes the app
     expect(env.visibleViews()).toEqual(["approve-network"]);
     expect(env.pageErrors).toEqual([]);
 });
+
+// The background opens the approval window as wide as the page, but the
+// browser counts the window's frame in that width, and a screen taller than
+// the window takes a vertical scrollbar out of it too
+// (https://git.eeqj.de/sneak/AutistMask/issues/518). The browser suites run
+// without frames, and only the Firefox suite's sign prompt at a zoom other
+// than 100%, so the widening is checked here too.
+//
+// A window 396 screen pixels wide whose page is drawn at `drawn` screen pixels
+// to the page pixel. Widening it gives the page its new width, less the 15
+// screen pixels of the scrollbar the approval screen has, and then calls the
+// page's resize listeners, each of which asked to be called once.
+function windowsStub(type, drawn) {
+    const updates = [];
+    return {
+        updates,
+        getCurrent: (done) => done({ id: 7, type, width: 396 }),
+        update: (id, info, done) => {
+            updates.push({ id, info });
+            done({});
+            globalThis.document.documentElement.clientWidth = Math.floor(
+                (info.width - 15) / drawn,
+            );
+            const resized = globalThis.window.listeners.resize || [];
+            globalThis.window.listeners.resize = [];
+            for (const fn of resized) fn();
+        },
+    };
+}
+
+// The approval page's own tab is at `zoom`. Asked without a tab id, Firefox
+// answers for the window focused last, here a site's tab at 100%.
+function tabsStub(zoom) {
+    return {
+        getCurrent: (done) => done({ id: 11 }),
+        getZoom: (...args) => {
+            const done = args.pop();
+            done(args[0] === 11 ? zoom : 1);
+        },
+    };
+}
+
+// An approval window at `zoom`, `clientWidth` page pixels wide before its
+// screen is up, whose background holds its answer until the test gives it.
+async function bootZoomedApprovalWindow(windows, zoom, clientWidth) {
+    let answer = null;
+    const env = await bootPopup(unversionedValidProfile(), {
+        search: "?approval=approval-1",
+        runtime: {
+            connect: () => ({ postMessage: () => {} }),
+            sendMessage: (msg, reply) => {
+                if (msg.type === "AUTISTMASK_GET_APPROVAL") answer = reply;
+            },
+        },
+        windows,
+        tabs: tabsStub(zoom),
+        documentElement: { scrollWidth: 396, clientWidth },
+    });
+    return { env, answer };
+}
+
+test("at 150% zoom the approval window widens by what its screen lacks, scrollbar included", async () => {
+    const windows = windowsStub("popup", 1.5);
+    // At 150% a window 396 screen pixels wide shows 264 page pixels.
+    const { env, answer } = await bootZoomedApprovalWindow(windows, 1.5, 264);
+
+    // Not before there is a screen to fit.
+    expect(windows.updates).toEqual([]);
+
+    // The screen is taller than the window, so once it is up a vertical
+    // scrollbar takes 15 screen pixels, 10 page pixels at 150%.
+    env.document.documentElement.clientWidth = 254;
+    answer({
+        type: "network",
+        origin: "https://dapp.example",
+        currentNetworkId: "mainnet",
+        requestedNetworkId: "sepolia",
+        isPhishingDomain: false,
+    });
+    await settle();
+
+    // 396 - 254 = 142 page pixels short, which at 150% is 213 screen pixels.
+    // At the 100% of the site's tab it would be 142, and the screen would
+    // still not fit.
+    expect(env.visibleViews()).toEqual(["approve-network"]);
+    expect(windows.updates).toEqual([{ id: 7, info: { width: 609 } }]);
+    expect(env.document.documentElement.clientWidth).toBe(396);
+    expect(env.pageErrors).toEqual([]);
+});
+
+test("at 170% the approval window is widened again while its screen still falls short", async () => {
+    // Firefox reports 170% as 1.7 but draws a page pixel about 1.714 screen
+    // pixels wide, so a window 396 wide shows 231 page pixels.
+    const windows = windowsStub("popup", 1.714);
+    const { env, answer } = await bootZoomedApprovalWindow(windows, 1.7, 231);
+
+    // Less the scrollbar once the screen is up.
+    env.document.documentElement.clientWidth = 222;
+    answer({
+        type: "network",
+        origin: "https://dapp.example",
+        currentNetworkId: "mainnet",
+        requestedNetworkId: "sepolia",
+        isPhishingDomain: false,
+    });
+    await settle();
+
+    // 174 page pixels short, so 296 screen pixels wider at 1.7. That shows 394
+    // page pixels, still 2 short, so 4 screen pixels wider again.
+    expect(windows.updates).toEqual([
+        { id: 7, info: { width: 692 } },
+        { id: 7, info: { width: 696 } },
+    ]);
+    const page = env.document.documentElement;
+    expect(page.scrollWidth).toBeLessThanOrEqual(page.clientWidth);
+    expect(env.pageErrors).toEqual([]);
+});
+
+test("a connection prompt in the toolbar popup leaves the browser window alone", async () => {
+    const windows = windowsStub("normal", 1.5);
+    const { env, answer } = await bootZoomedApprovalWindow(windows, 1.5, 264);
+
+    answer({ origin: "https://dapp.example", isPhishingDomain: false });
+    await settle();
+
+    expect(env.visibleViews()).toEqual(["approve-site"]);
+    expect(windows.updates).toEqual([]);
+    expect(env.pageErrors).toEqual([]);
+});

tests/backgroundApproval.test.js

@@ -321,9 +321,10 @@ function loadBackground(options) {
     require("../src/background/index");
 
     // Send a message the way the browser would, and hand back whatever the
-    // handler passed to sendResponse.
-    function send(msg, sender) {
-        const sendResponse = jest.fn();
+    // handler passed to sendResponse. `onResponse`, when given, receives the
+    // answer when the handler sends it, as the sender's callback does.
+    function send(msg, sender, onResponse) {
+        const sendResponse = jest.fn(onResponse);
         const kept = messageListener(msg, sender || {}, sendResponse);
         return { sendResponse, kept };
     }
@@ -1161,9 +1162,12 @@ describe("a nonce collision is reported as a transaction that did not go out", (
         const pending = bg.requestTx();
         await settle();
 
+        // As ethers throws it: its own classification, and the node's
+        // JSON-RPC error under info.error.
         bg.broadcastTransaction.mockRejectedValue(
             Object.assign(new Error("nonce too low"), {
                 code: "NONCE_EXPIRED",
+                info: { error: { code: -32000, message: "nonce too low" } },
             }),
         );
         const answer = bg.send(
@@ -1182,8 +1186,10 @@ describe("a nonce collision is reported as a transaction that did not go out", (
             retryable: false,
             stage: "nonce",
         });
+        // The wallet's sentence, with the node's own code.
         expect(pending.result()).toEqual({
             error: {
+                code: -32000,
                 message: expect.stringMatching(
                     /transaction was not sent, because its nonce/,
                 ),
@@ -1233,6 +1239,7 @@ describe("a nonce collision is reported as a transaction that did not go out", (
         });
         expect(second.result()).toEqual({
             error: {
+                code: -32603,
                 message: expect.stringMatching(/nonce had already been used/),
             },
         });
@@ -1323,6 +1330,7 @@ describe("what the approval is verified against", () => {
         );
         expect(pending.result()).toEqual({
             error: {
+                code: -32603,
                 message: expect.stringMatching(/approved maximum fee per gas/),
             },
         });
@@ -1382,7 +1390,10 @@ describe("what the approval is verified against", () => {
             expect.objectContaining({ retryable: false, stage: "verify" }),
         );
         expect(pending.result()).toEqual({
-            error: { message: expect.stringMatching(/active address changed/) },
+            error: {
+                code: -32603,
+                message: expect.stringMatching(/active address changed/),
+            },
         });
     });
 
@@ -1526,7 +1537,10 @@ describe("what the approval is verified against", () => {
             }),
         );
         expect(pending.result()).toEqual({
-            error: { message: expect.stringMatching(/active address changed/) },
+            error: {
+                code: -32603,
+                message: expect.stringMatching(/active address changed/),
+            },
         });
     });
 
@@ -1576,7 +1590,9 @@ describe("what the approval is verified against", () => {
             error: refusal,
             retryable: false,
         });
-        expect(pending.result()).toEqual({ error: { message: refusal } });
+        expect(pending.result()).toEqual({
+            error: { code: -32603, message: refusal },
+        });
     });
 
     // ethers signs a `bool` field sent as the string "false" as true, and one
@@ -1611,7 +1627,9 @@ describe("what the approval is verified against", () => {
                 error: refusal,
                 retryable: false,
             });
-            expect(pending.result()).toEqual({ error: { message: refusal } });
+            expect(pending.result()).toEqual({
+                error: { code: -32603, message: refusal },
+            });
         },
     );
 
@@ -1649,6 +1667,7 @@ describe("what the approval is verified against", () => {
 
         expect(pending.result()).toEqual({
             error: {
+                code: -32603,
                 message: expect.stringMatching(
                     /active address changed while this transaction was being prepared/,
                 ),
@@ -1671,8 +1690,11 @@ describe("what the approval is verified against", () => {
         const pending = bg.requestTx();
         await settle();
 
+        // A failure with no node error in it is answered as the wallet's own;
+        // tests/rpcErrorCodes.test.js has the node's own revert.
         expect(pending.result()).toEqual({
             error: {
+                code: -32603,
                 message: expect.stringMatching(
                     /could not be prepared.*execution reverted/,
                 ),
@@ -2594,9 +2616,9 @@ async function siteAccounts(bg, origin) {
     return sendResponse.mock.calls[0][0];
 }
 
-// A site connected without "Remember" is held only in the background's memory,
-// keyed to the address it was connected to. Removing that address, or the
-// wallet holding it, must end the connection as part of the removal itself.
+// A site connected without "Remember" is held only in the background's session
+// storage, keyed to the address it was connected to. Removing that address, or
+// the wallet holding it, must end the connection as part of the removal itself.
 // The accountsChanged broadcast the views send afterwards also clears it, but
 // only when the active address moved, and nothing waits for it to arrive.
 //
@@ -2775,8 +2797,7 @@ describe("removing a site in Settings disconnects it", () => {
         const element = (id) => (lists[id] ||= fakeSiteList());
         global.document = { getElementById: element };
         global.chrome.runtime.sendMessage = (msg, callback) => {
-            const { sendResponse } = bg.send(msg, bg.fromPopup);
-            if (callback) callback(sendResponse.mock.calls[0]?.[0]);
+            bg.send(msg, bg.fromPopup, callback);
         };
         await require("../src/shared/state").loadState();
         await require("../src/popup/views/settings").renderSiteLists();
@@ -2930,7 +2951,7 @@ describe("where an approval window opens", () => {
         await settle();
 
         expect(bg.created).toHaveLength(1);
-        expect(bg.created[0]).toMatchObject({ left: 460, top: 60 });
+        expect(bg.created[0]).toMatchObject({ left: 442, top: 60 });
     });
 
     test("not centred on an approval window the user was last in", async () => {
@@ -2947,7 +2968,7 @@ describe("where an approval window opens", () => {
         bg.requestSign();
         await settle();
 
-        // Centred, it would be at left 900, the position the browser refused.
+        // Centred, it would be at left 882, the position the browser refused.
         expect(bg.created).toHaveLength(1);
         expect(bg.created[0].left).toBeUndefined();
         expect(bg.created[0].top).toBeUndefined();
@@ -2969,7 +2990,7 @@ describe("where an approval window opens", () => {
         await settle();
 
         expect(bg.created).toHaveLength(2);
-        expect(bg.created[0]).toMatchObject({ left: 1520, top: 750 });
+        expect(bg.created[0]).toMatchObject({ left: 1502, top: 750 });
         expect(bg.created[1].left).toBeUndefined();
         expect(bg.created[1].top).toBeUndefined();
 

tests/connectedSitesWorkerRestart.test.js

@@ -0,0 +1,354 @@
+// A site allowed without "Remember my choice for this site" stays connected
+// when the background worker is stopped and started again
+// (https://git.eeqj.de/sneak/AutistMask/issues/526).
+//
+// Chrome stops the worker after about 30 seconds idle and evaluates the
+// module afresh on the next event, so nothing held at module scope survives
+// it. Such a connection used to be held exactly there, and so lasted until the
+// first idle spell. Each test here makes the connection in one load of the
+// background, loads the module afresh over the same storage, as the browser
+// does, and asks the new one. The paths that end a connection are driven after
+// that restart, so each is shown to end what the earlier worker stored.
+
+const { networkById } = require("../src/shared/networks");
+const { makeStorageStub } = require("./support/storageStub");
+const {
+    removeAddressFromState,
+    removeWalletFromState,
+} = require("../src/shared/walletDelete");
+
+const ADDRESS = "0x66133E8ea0f5D1d612D2502a968757D1048c214a";
+const OTHER_ADDRESS = "0x70997970C51812dc3A010C7d01b50e0d17dc79C8";
+
+const SITE = "https://dapp.example";
+const OTHER_SITE = "https://other.example";
+
+const EXT_URL = "chrome-extension://autistmask/";
+const FROM_POPUP = { url: EXT_URL + "src/popup/index.html" };
+
+// One wallet with two addresses, so that one of them can be removed, and no
+// remembered sites, so that every connection here is one made without
+// "Remember".
+function storedProfile() {
+    const mainnet = networkById("mainnet");
+    return {
+        hasWallet: true,
+        wallets: [
+            {
+                name: "Wallet 1",
+                type: "hd",
+                addresses: [
+                    { address: ADDRESS, balance: "0", tokenBalances: [] },
+                    { address: OTHER_ADDRESS, balance: "0", tokenBalances: [] },
+                ],
+            },
+        ],
+        activeAddress: ADDRESS,
+        networkId: "mainnet",
+        rpcUrl: mainnet.defaultRpcUrl,
+        blockscoutUrl: mainnet.defaultBlockscoutUrl,
+        allowedSites: {},
+        deniedSites: {},
+        trackedTokens: [],
+    };
+}
+
+async function settle() {
+    for (let i = 0; i < 50; i++) await Promise.resolve();
+}
+
+afterEach(() => {
+    delete global.chrome;
+    jest.resetModules();
+});
+
+// Load the background module afresh, as the browser does when it starts the
+// worker, over `storage`. The storage stub stands in for the browser's own
+// storage, local and session, so it outlives each load.
+function startWorker(storage) {
+    jest.resetModules();
+    jest.doMock("../src/shared/balances", () => ({
+        getProvider: () => ({}),
+        refreshBalances: jest.fn(async () => {}),
+    }));
+    jest.doMock("../src/shared/phishingDomains", () => ({
+        isPhishingDomain: () => false,
+    }));
+    jest.doMock("../src/shared/alarms", () => ({
+        BALANCE_REFRESH_ALARM: "balance",
+        BALANCE_REFRESH_PERIOD_MINUTES: 1,
+        ensureRecurringAlarms: jest.fn(async () => {}),
+        registerAlarmHandlers: jest.fn(),
+    }));
+
+    let messageListener = null;
+    let connectListener = null;
+    // Every URL the toolbar popup was set to open: a site's connection prompt
+    // is shown there, so this is where its approval id appears.
+    const toolbarPopups = [];
+    const windowsCreated = [];
+    const sentToTabs = [];
+
+    global.chrome = {
+        storage,
+        runtime: {
+            getURL: (path) => EXT_URL + path,
+            onMessage: {
+                addListener: (fn) => {
+                    messageListener = fn;
+                },
+            },
+            onConnect: {
+                addListener: (fn) => {
+                    connectListener = fn;
+                },
+            },
+            getPlatformInfo: (cb) => cb({ os: "linux" }),
+            // What the popup sends reaches the worker from the extension's own
+            // page.
+            sendMessage: (msg, callback) => {
+                messageListener(msg, FROM_POPUP, callback || (() => {}));
+            },
+            lastError: null,
+        },
+        windows: {
+            getLastFocused: (cb) => cb(null),
+            create: (options, cb) => {
+                windowsCreated.push(options);
+                cb({ id: windowsCreated.length });
+            },
+            remove: (id, cb) => {
+                if (cb) cb();
+            },
+            onRemoved: { addListener: () => {} },
+        },
+        tabs: {
+            query: (q, cb) => cb([{ id: 1, url: SITE + "/app" }]),
+            sendMessage: (tabId, msg, cb) => {
+                sentToTabs.push(msg);
+                if (cb) cb();
+            },
+        },
+        action: {
+            setPopup: (o) => {
+                toolbarPopups.push(o.popup);
+            },
+            openPopup: () => Promise.resolve(),
+        },
+    };
+
+    require("../src/background/index");
+
+    // A request from a site, answered once the worker has had time to answer.
+    async function rpc(method, origin, params) {
+        let response = null;
+        messageListener(
+            { type: "AUTISTMASK_RPC", method, params: params || [] },
+            { origin },
+            (r) => {
+                response = r;
+            },
+        );
+        await settle();
+        return response;
+    }
+
+    // A message from the popup, and the worker's answer to it.
+    async function fromPopup(msg) {
+        let response;
+        messageListener(msg, FROM_POPUP, (r) => {
+            response = r;
+        });
+        await settle();
+        return response;
+    }
+
+    // The site asks to connect, and the user allows it in the prompt with
+    // "Remember my choice for this site" left unchecked.
+    async function connectWithoutRemember(origin) {
+        let response = null;
+        messageListener(
+            { type: "AUTISTMASK_RPC", method: "eth_requestAccounts" },
+            { origin },
+            (r) => {
+                response = r;
+            },
+        );
+        await settle();
+        const id = new URL(toolbarPopups.at(-1), EXT_URL).searchParams.get(
+            "approval",
+        );
+        const decisionListeners = [];
+        const port = {
+            name: "approval:" + id,
+            sender: { url: EXT_URL + "src/popup/index.html?approval=" + id },
+            onMessage: { addListener: (fn) => decisionListeners.push(fn) },
+            onDisconnect: { addListener: () => {} },
+        };
+        connectListener(port);
+        for (const fn of decisionListeners) {
+            fn(
+                {
+                    type: "AUTISTMASK_APPROVAL_DECISION",
+                    approved: true,
+                    remember: false,
+                },
+                port,
+            );
+        }
+        await settle();
+        return response;
+    }
+
+    return {
+        rpc,
+        fromPopup,
+        connectWithoutRemember,
+        windowsCreated,
+        sentToTabs,
+    };
+}
+
+// A site connected without "Remember" in one worker, and the worker started
+// again over the same storage, where the site is still connected.
+async function connectedThenRestarted() {
+    const storage = makeStorageStub({ autistmask: storedProfile() });
+    const first = startWorker(storage);
+    expect(await first.connectWithoutRemember(SITE)).toEqual({
+        result: [ADDRESS],
+    });
+    const worker = startWorker(storage);
+    expect(await worker.rpc("eth_accounts", SITE)).toEqual({
+        result: [ADDRESS],
+    });
+    return { storage, worker };
+}
+
+describe("a site allowed without Remember, after the worker restarts", () => {
+    test("is still told the address, and is not asked again", async () => {
+        const { worker } = await connectedThenRestarted();
+
+        expect(await worker.rpc("eth_accounts", SITE)).toEqual({
+            result: [ADDRESS],
+        });
+        expect(await worker.rpc("eth_requestAccounts", SITE)).toEqual({
+            result: [ADDRESS],
+        });
+    });
+
+    test("is still listed under Connected Sites in Settings", async () => {
+        const { worker } = await connectedThenRestarted();
+
+        expect(
+            await worker.fromPopup({ type: "AUTISTMASK_GET_CONNECTED_SITES" }),
+        ).toEqual([SITE]);
+    });
+
+    test("may still ask for a signature", async () => {
+        // Refused with 4100 before the fix. Allowed, it raises the signing
+        // prompt and waits on the user.
+        const { worker } = await connectedThenRestarted();
+
+        const response = await worker.rpc("personal_sign", SITE, [
+            "0x48656c6c6f",
+            ADDRESS,
+        ]);
+
+        expect(response).toBeNull();
+        expect(worker.windowsCreated).toHaveLength(1);
+    });
+
+    test("is not connected after the browser restarts", async () => {
+        // The browser empties session storage when it closes; the wallet's
+        // own storage keeps nothing of the connection.
+        const { storage } = await connectedThenRestarted();
+        const afterBrowserRestart = startWorker(
+            makeStorageStub({ autistmask: storage.read("autistmask") }),
+        );
+
+        expect(await afterBrowserRestart.rpc("eth_accounts", SITE)).toEqual({
+            result: [],
+        });
+    });
+});
+
+describe("each way a connection allowed without Remember ends, after the worker restarts", () => {
+    test("removing the site in Settings", async () => {
+        const { worker } = await connectedThenRestarted();
+        expect(await worker.connectWithoutRemember(OTHER_SITE)).toEqual({
+            result: [ADDRESS],
+        });
+
+        await worker.fromPopup({
+            type: "AUTISTMASK_REMOVE_SITE",
+            origin: SITE,
+        });
+
+        expect(await worker.rpc("eth_accounts", SITE)).toEqual({ result: [] });
+        expect(worker.sentToTabs).toEqual([
+            {
+                type: "AUTISTMASK_EVENT",
+                eventName: "accountsChanged",
+                data: [],
+            },
+        ]);
+        expect(
+            await worker.fromPopup({ type: "AUTISTMASK_GET_CONNECTED_SITES" }),
+        ).toEqual([OTHER_SITE]);
+        expect(await worker.rpc("eth_accounts", OTHER_SITE)).toEqual({
+            result: [ADDRESS],
+        });
+    });
+
+    test("switching to another address", async () => {
+        // Switched away and back again, so the answer turns on the connection
+        // having ended rather than on which address is active.
+        const { storage, worker } = await connectedThenRestarted();
+        const switched = { ...storage.read("autistmask") };
+
+        switched.activeAddress = OTHER_ADDRESS;
+        storage.write("autistmask", switched);
+        await worker.fromPopup({ type: "AUTISTMASK_ACTIVE_CHANGED" });
+        switched.activeAddress = ADDRESS;
+        storage.write("autistmask", switched);
+
+        expect(await worker.rpc("eth_accounts", SITE)).toEqual({ result: [] });
+        expect(
+            await worker.fromPopup({ type: "AUTISTMASK_GET_CONNECTED_SITES" }),
+        ).toEqual([]);
+    });
+
+    // The two below ask while storage still names the removed address as
+    // active, because the popup has not saved yet, so the answer turns on the
+    // connection alone.
+    test("removing the connected address", async () => {
+        const { storage, worker } = await connectedThenRestarted();
+
+        const popupState = storage.read("autistmask");
+        expect(removeAddressFromState(popupState, 0, 0).removed).toBe(true);
+        await settle();
+
+        expect(await worker.rpc("eth_accounts", SITE)).toEqual({ result: [] });
+    });
+
+    test("removing the wallet holding the connected address", async () => {
+        const { storage, worker } = await connectedThenRestarted();
+
+        removeWalletFromState(storage.read("autistmask"), 0);
+        await settle();
+
+        expect(await worker.rpc("eth_accounts", SITE)).toEqual({ result: [] });
+    });
+
+    test("removing a different address leaves it connected", async () => {
+        const { storage, worker } = await connectedThenRestarted();
+
+        const popupState = storage.read("autistmask");
+        expect(removeAddressFromState(popupState, 0, 1).removed).toBe(true);
+        await settle();
+
+        expect(await worker.rpc("eth_accounts", SITE)).toEqual({
+            result: [ADDRESS],
+        });
+    });
+});

tests/e2e/firefox/run.js

@@ -394,6 +394,26 @@ async function waitForApprovalWindow(d, timeout = 30000) {
     }
 }
 
+// Firefox keeps one zoom per site, so a zoom set on the popup's tab holds for
+// every page of the extension, the approval windows included.
+async function setExtensionZoom(env, zoom) {
+    const d = env.driver;
+    await d.switchToWindow(env.popupWindow);
+    const outcome = await d.executeAsync(
+        `const done = arguments[arguments.length - 1];
+         const zoom = arguments[0];
+         browser.tabs
+             .getCurrent()
+             .then((tab) => browser.tabs.setZoom(tab.id, zoom))
+             .then(() => done({}), (e) => done({ error: String(e) }));`,
+        [zoom],
+    );
+    assert(
+        outcome && !outcome.error,
+        "could not set the extension's zoom: " + (outcome && outcome.error),
+    );
+}
+
 function startRequest(d, key, method, params) {
     return d.execute(
         "window.__dapp.start(arguments[0], arguments[1], arguments[2]);" +
@@ -633,6 +653,14 @@ step(
     "personal_sign returns a signature that recovers to the address",
     async (env) => {
         const d = env.driver;
+        // The window is opened as wide as the page, and widened once the
+        // screen is up if it still scrolls sideways
+        // (https://git.eeqj.de/sneak/AutistMask/issues/518). This suite is
+        // where that is checked: the Chrome suite's approval windows open at
+        // 1280x720 whatever width the extension asks for. At 170%, one of
+        // Firefox's zoom steps, the page is drawn a little larger than the
+        // 1.7 Firefox reports, so a single widening leaves it a pixel short.
+        await setExtensionZoom(env, 1.7);
         await d.switchToWindow(env.dappWindow);
         await startRequest(d, "sign", "personal_sign", [SIGN_HEX, env.address]);
 
@@ -640,6 +668,12 @@ step(
         await d.switchToWindow(popup);
         await d.waitVisible("#view-approve-sign");
 
+        await d.waitFor(
+            "the sign prompt to fit its window without scrolling sideways",
+            "return document.documentElement.scrollWidth <=" +
+                " document.documentElement.clientWidth;",
+        );
+
         const screen = await d.execute(
             `return {
              origin: document.getElementById("approve-sign-origin").textContent,
@@ -674,6 +708,7 @@ step(
 
         await d.switchToWindow(env.dappWindow);
         const outcome = await settleRequest(d, "sign");
+        await setExtensionZoom(env, 1);
         assert(
             outcome.settled === "resolved",
             "personal_sign did not resolve: " + JSON.stringify(outcome),

tests/e2e/run.js

@@ -3861,10 +3861,8 @@ test("eth_requestAccounts approved returns the selected address (#183)", async (
         // all; this measures that the whole address is visible (#517).
         await assertAddressesFit(popup, "the connection prompt");
 
-        // Remembered, so the connection survives a background worker that MV3
-        // terminates after 30 seconds idle. The in-memory connectedSites map
-        // does not, and the sign and transaction tests below all require the
-        // origin to still be authorized.
+        // Remembered, because the sign and transaction tests below all
+        // require the origin to still be authorized.
         await popup.check("#approve-remember");
         await clickAndClose(popup, "#btn-approve");
 

tests/e2e/slowApproval.js

@@ -22,6 +22,11 @@
 // Before the approvals are raised it watches the worker stop on its own, so a
 // run in which something else keeps the worker running cannot pass.
 //
+// The site is connected without "Remember", and once the worker has stopped
+// the program requires the site still to be told the address: such a
+// connection used to be held in the worker's memory and ended with it
+// (https://git.eeqj.de/sneak/AutistMask/issues/526).
+//
 // The dApp page and the stub node are the loopback ones the Firefox suite also
 // uses (tests/e2e/dapp.js). The site is connected and the node chosen
 // through the extension's own screens, so nothing is written to its storage
@@ -311,8 +316,8 @@ async function main() {
         );
         await send("Target.closeTarget", { targetId: popup.targetId });
 
-        // The site, connected through the real prompt with "Remember", so
-        // the connection is stored rather than held by the worker.
+        // The site, connected through the real prompt without "Remember", so
+        // the connection is one that has to outlive the worker stopping below.
         const dapp = await openPage(node.url);
         await until("the injected provider", () =>
             dapp.evaluate("!!window.ethereum && !!window.__dapp"),
@@ -329,7 +334,7 @@ async function main() {
             inPrompt(shows("view-approve-site")),
         );
         await inPrompt(
-            "document.getElementById('approve-remember').checked = true",
+            "document.getElementById('approve-remember').checked = false",
         );
         // The prompt closes itself on the click.
         await inPrompt(click("btn-approve")).catch(() => {});
@@ -365,6 +370,20 @@ async function main() {
                 "s",
         );
 
+        // The site's request starts the worker again, and the new worker still
+        // has the connection allowed without "Remember"
+        // (https://git.eeqj.de/sneak/AutistMask/issues/526).
+        const stillConnected = await dapp.evaluate(
+            "window.ethereum.request({ method: 'eth_accounts' })",
+        );
+        check(
+            "a site allowed without Remember is still connected after the worker stopped",
+            Array.isArray(stillConnected) &&
+                stillConnected.length === 1 &&
+                getAddress(stillConnected[0]) === address,
+            "eth_accounts answered " + JSON.stringify(stillConnected),
+        );
+
         // A transaction approval and a signature approval, both open at once.
         await dapp.evaluate(
             "window.__dapp.start('tx', 'eth_sendTransaction', [" +

tests/firstWalletActiveAddress.test.js

@@ -0,0 +1,141 @@
+// Adding the first wallet left no address active until the popup was reopened,
+// so Send and Receive on Home only said "No active address selected."
+// (https://git.eeqj.de/sneak/AutistMask/issues/512). Each test adds a wallet
+// through one of the three import tabs and checks which address is active by
+// opening Receive from Home in the same popup.
+
+const { HDNodeWallet, Mnemonic, Wallet } = require("ethers");
+
+const {
+    bootPopup,
+    cleanupPopup,
+    unversionedValidProfile,
+    ADDRESS,
+} = require("./support/popupBoot");
+
+const PHRASE =
+    "abandon abandon abandon abandon abandon abandon " +
+    "abandon abandon abandon abandon abandon about";
+const PRIVATE_KEY = "0x" + "11".repeat(32);
+// The master key of PHRASE, so its first address is the phrase's.
+const XPRV = HDNodeWallet.fromSeed(
+    Mnemonic.fromPhrase(PHRASE).computeSeed(),
+).extendedKey;
+const PASSWORD = "correct horse battery staple";
+
+const PHRASE_ADDRESS = HDNodeWallet.fromPhrase(PHRASE).address;
+
+// Addresses 1 and 2 of PHRASE used, address 0 not: a scan that answers these
+// replaces the wallet's list with one that leaves out its first address.
+const account = HDNodeWallet.fromPhrase(PHRASE, "", "m/44'/60'/0'/0");
+const used = [1, 2].map((index) => ({
+    address: account.deriveChild(index).address,
+    index,
+}));
+
+const TABS = [
+    {
+        tab: "tab-mnemonic",
+        field: "wallet-mnemonic",
+        secret: PHRASE,
+        address: PHRASE_ADDRESS,
+    },
+    {
+        tab: "tab-privkey",
+        field: "import-private-key",
+        secret: PRIVATE_KEY,
+        address: new Wallet(PRIVATE_KEY).address,
+    },
+    {
+        tab: "tab-xprv",
+        field: "import-xprv-key",
+        secret: XPRV,
+        address: PHRASE_ADDRESS,
+    },
+];
+
+// Fills in the open AddWallet screen and presses "Import".
+async function importOn(page, { tab, field, secret }) {
+    await page.click(tab);
+    page.node(field).value = secret;
+    page.node("add-wallet-password").value = PASSWORD;
+    page.node("add-wallet-password-confirm").value = PASSWORD;
+    await page.click("btn-add-wallet-confirm");
+}
+
+afterEach(() => {
+    cleanupPopup();
+});
+
+describe("the first wallet's first address is active right away", () => {
+    test.each(TABS)("added from $tab, Receive opens on it", async (entry) => {
+        const page = await bootPopup(undefined);
+        expect(page.pageErrors).toEqual([]);
+        await page.click("btn-welcome-add");
+        await importOn(page, entry);
+        expect(page.visibleViews()).toEqual(["main"]);
+
+        await page.click("btn-main-receive");
+        expect(page.visibleViews()).toEqual(["receive"]);
+        expect(page.node("receive-address-block").dataset.full).toBe(
+            entry.address,
+        );
+    });
+});
+
+describe("a scan that leaves out the first address", () => {
+    // The key tab runs no scan.
+    test.each(TABS.filter((t) => t.tab !== "tab-privkey"))(
+        "added from $tab, the scan's first address is active",
+        async (entry) => {
+            const page = await bootPopup(undefined);
+            const { scanForAddresses } = require("../src/shared/balances");
+            scanForAddresses.mockResolvedValueOnce({
+                addresses: used,
+                nextIndex: 3,
+            });
+            await page.click("btn-welcome-add");
+            await importOn(page, entry);
+
+            expect(page.storage.read("autistmask").activeAddress).toBe(
+                used[0].address,
+            );
+            expect(globalThis.chrome.runtime.sendMessage).toHaveBeenCalledWith({
+                type: "AUTISTMASK_ACTIVE_CHANGED",
+            });
+            await page.click("btn-main-receive");
+            expect(page.node("receive-address-block").dataset.full).toBe(
+                used[0].address,
+            );
+        },
+    );
+});
+
+describe("adding a wallet while an address is active", () => {
+    test.each(TABS)(
+        "added from $tab, the active address is unchanged",
+        async (entry) => {
+            const page = await bootPopup(unversionedValidProfile());
+            expect(page.pageErrors).toEqual([]);
+            // The phrase and xprv scans leave out the new wallet's first
+            // address, which was never active here. The key tab runs no scan.
+            const { scanForAddresses } = require("../src/shared/balances");
+            scanForAddresses.mockResolvedValueOnce({
+                addresses: used,
+                nextIndex: 3,
+            });
+            await page.click("btn-add-wallet-bottom");
+            await importOn(page, entry);
+            expect(page.visibleViews()).toEqual(["main"]);
+
+            expect(page.storage.read("autistmask").activeAddress).toBe(ADDRESS);
+            expect(
+                globalThis.chrome.runtime.sendMessage,
+            ).not.toHaveBeenCalledWith({ type: "AUTISTMASK_ACTIVE_CHANGED" });
+            await page.click("btn-main-receive");
+            expect(page.node("receive-address-block").dataset.full).toBe(
+                ADDRESS,
+            );
+        },
+    );
+});

tests/rpcErrorCodes.test.js

@@ -0,0 +1,282 @@
+// What a page is told when a request fails
+// (https://git.eeqj.de/sneak/AutistMask/issues/533).
+//
+// EIP-1193 gives every rejected request a numeric `code`, and lets it carry
+// `data`. A node's error used to reach the page as its message alone: a
+// reverting eth_call lost code 3 and the revert data a site needs to decode
+// the revert, and a site could not tell that failure from any other.
+//
+// Each request here goes from a page through the real background to a fake
+// node, and what is checked is the answer the background gives the page. The
+// content script relays that answer as it is, and src/content/inpage.js turns
+// its code and data into the error the page catches (tests/inpageErrors.test.js).
+//
+// The background reaches a node two ways, and the fake node answers both:
+// fetch(), which the read-only methods are proxied through, and ethers' own
+// HTTP transport, which a transaction is prepared through.
+
+const { AbiCoder } = require("ethers");
+const { networkById } = require("../src/shared/networks");
+const { makeStorageStub } = require("./support/storageStub");
+
+const ORIGIN = "https://dapp.example";
+const ADDRESS = "0x66133E8ea0f5D1d612D2502a968757D1048c214a";
+const TOKEN = "0x1111111111111111111111111111111111111111";
+const SEPOLIA = networkById("sepolia");
+
+// Error("bal"), which a token whose transfer() does require(..., "bal")
+// reverts with when the balance is too low.
+const REVERT_DATA =
+    "0x08c379a0" +
+    AbiCoder.defaultAbiCoder().encode(["string"], ["bal"]).slice(2);
+
+// What a node answers for a call that reverts, and for an address that is not
+// one.
+const REVERTED = {
+    code: 3,
+    message: "execution reverted: bal",
+    data: REVERT_DATA,
+};
+const INVALID_ADDRESS = { code: -32602, message: "invalid string length" };
+
+const WITH_ADDRESS = {
+    hasWallet: true,
+    wallets: [
+        {
+            name: "Wallet 1",
+            type: "hd",
+            xpub: "xpub-1",
+            addresses: [
+                { address: ADDRESS, balance: "0.0", tokenBalances: [] },
+            ],
+        },
+    ],
+    activeAddress: ADDRESS,
+    networkId: "sepolia",
+    rpcUrl: SEPOLIA.defaultRpcUrl,
+    blockscoutUrl: SEPOLIA.defaultBlockscoutUrl,
+    allowedSites: { [ADDRESS]: [ORIGIN] },
+    deniedSites: {},
+    trackedTokens: [],
+};
+
+const NO_ADDRESS = {
+    ...WITH_ADDRESS,
+    hasWallet: false,
+    wallets: [],
+    activeAddress: null,
+    allowedSites: {},
+};
+
+const realFetch = globalThis.fetch;
+
+afterEach(() => {
+    delete global.chrome;
+    globalThis.fetch = realFetch;
+});
+
+// The background, over a stored profile, with a node that answers each
+// JSON-RPC method from `node`: a method's entry is the result, or
+// `{ error }` for the error the node answers with. A method not in `node`
+// is answered "method not found", so a test that reaches one fails on it.
+// `node` null is a node that cannot be reached at all.
+function loadBackground(profile, node) {
+    jest.resetModules();
+
+    jest.doMock("../src/shared/phishingDomains", () => ({
+        isPhishingDomain: () => false,
+    }));
+    jest.doMock("../src/shared/alarms", () => ({
+        BALANCE_REFRESH_ALARM: "balance",
+        BALANCE_REFRESH_PERIOD_MINUTES: 1,
+        ensureRecurringAlarms: jest.fn(async () => {}),
+        registerAlarmHandlers: jest.fn(),
+    }));
+
+    function reply({ id, method }) {
+        const entry = node[method];
+        if (entry === undefined) {
+            return {
+                jsonrpc: "2.0",
+                id,
+                error: { code: -32601, message: "method not found: " + method },
+            };
+        }
+        if (entry && entry.error)
+            return { jsonrpc: "2.0", id, error: entry.error };
+        return { jsonrpc: "2.0", id, result: entry };
+    }
+
+    globalThis.fetch = jest.fn(async (url, opts) => {
+        if (!node) throw new TypeError("fetch failed");
+        return { status: 200, json: async () => reply(JSON.parse(opts.body)) };
+    });
+
+    // The ethers the background is about to load: jest.resetModules() above
+    // means it is a fresh copy, not the one this file required at the top.
+    require("ethers").FetchRequest.registerGetUrl(async (req) => {
+        if (!node) throw new Error("connect ECONNREFUSED");
+        const body = JSON.parse(Buffer.from(req.body).toString("utf8"));
+        const answer = Array.isArray(body) ? body.map(reply) : reply(body);
+        return {
+            statusCode: 200,
+            statusMessage: "OK",
+            headers: { "content-type": "application/json" },
+            body: Buffer.from(JSON.stringify(answer)),
+        };
+    });
+
+    let messageListener = null;
+    global.chrome = {
+        storage: makeStorageStub({ autistmask: profile }),
+        runtime: {
+            getURL: (path) => "chrome-extension://autistmask/" + path,
+            onMessage: {
+                addListener: (fn) => {
+                    messageListener = fn;
+                },
+            },
+            onConnect: { addListener: () => {} },
+            lastError: null,
+        },
+        windows: { onRemoved: { addListener: () => {} } },
+        action: { setPopup: () => {} },
+    };
+
+    require("../src/background/index");
+
+    // The answer the page gets to one request.
+    return function request(method, params) {
+        return new Promise((resolve) => {
+            messageListener(
+                { type: "AUTISTMASK_RPC", method, params },
+                { origin: ORIGIN },
+                resolve,
+            );
+        });
+    };
+}
+
+const TRANSFER = {
+    from: ADDRESS,
+    to: TOKEN,
+    // transfer(ADDRESS, 1)
+    data:
+        "0xa9059cbb" +
+        AbiCoder.defaultAbiCoder()
+            .encode(["address", "uint256"], [ADDRESS, 1])
+            .slice(2),
+};
+
+describe("a node's error reaches the page with the node's code and data", () => {
+    test("a reverting eth_call", async () => {
+        const request = loadBackground(WITH_ADDRESS, {
+            eth_call: { error: REVERTED },
+        });
+
+        const answer = await request("eth_call", [TRANSFER, "latest"]);
+
+        expect(answer).toEqual({ error: REVERTED });
+    });
+
+    test("an eth_getBalance for an address that is not one", async () => {
+        const request = loadBackground(WITH_ADDRESS, {
+            eth_getBalance: { error: INVALID_ADDRESS },
+        });
+
+        const answer = await request("eth_getBalance", ["0x1234", "latest"]);
+
+        expect(answer).toEqual({ error: INVALID_ADDRESS });
+    });
+
+    // The wallet's own sentence, with the node's code and revert data, so the
+    // site can decode why its transaction would revert.
+    test("an eth_sendTransaction whose gas estimate reverts", async () => {
+        const request = loadBackground(WITH_ADDRESS, {
+            eth_getTransactionCount: "0x7",
+            eth_estimateGas: { error: REVERTED },
+        });
+
+        const answer = await request("eth_sendTransaction", [TRANSFER]);
+
+        expect(answer).toEqual({
+            error: {
+                code: REVERTED.code,
+                message: expect.stringMatching(
+                    /^The transaction could not be prepared: execution reverted/,
+                ),
+                data: REVERT_DATA,
+            },
+        });
+    });
+});
+
+// One request for each way a request is refused without the node's code: by
+// the wallet itself, or because the node could not be reached.
+describe("no rejected request reaches the page without a numeric code", () => {
+    test.each([
+        [
+            "eth_requestAccounts with no address",
+            NO_ADDRESS,
+            {},
+            "eth_requestAccounts",
+            [],
+            4100,
+        ],
+        [
+            "personal_sign with no address",
+            NO_ADDRESS,
+            {},
+            "personal_sign",
+            ["0x00", ADDRESS],
+            4100,
+        ],
+        [
+            "eth_signTypedData_v4 with no address",
+            NO_ADDRESS,
+            {},
+            "eth_signTypedData_v4",
+            [ADDRESS, "{}"],
+            4100,
+        ],
+        [
+            "eth_sendTransaction with no address",
+            NO_ADDRESS,
+            {},
+            "eth_sendTransaction",
+            [TRANSFER],
+            4100,
+        ],
+        [
+            "eth_sendTransaction with two different gas limits",
+            WITH_ADDRESS,
+            {},
+            "eth_sendTransaction",
+            [{ ...TRANSFER, gas: "0x5208", gasLimit: "0x5209" }],
+            -32602,
+        ],
+        [
+            "eth_call to a node that cannot be reached",
+            WITH_ADDRESS,
+            null,
+            "eth_call",
+            [TRANSFER, "latest"],
+            -32603,
+        ],
+        [
+            "eth_sendTransaction to a node that cannot be reached",
+            WITH_ADDRESS,
+            null,
+            "eth_sendTransaction",
+            [TRANSFER],
+            -32603,
+        ],
+    ])("%s", async (_name, profile, node, method, params, code) => {
+        const request = loadBackground(profile, node);
+
+        const answer = await request(method, params);
+
+        expect(answer.error.code).toBe(code);
+        expect(answer.error.message).toEqual(expect.any(String));
+    });
+});

tests/rpcOrigin.test.js

@@ -8,8 +8,15 @@
 // and a request the browser said nothing about was credited to whatever the
 // page wrote (https://git.eeqj.de/sneak/AutistMask/issues/407).
 //
-// Every sender here lacks sender.origin, as on old Firefox. The connection
-// check on eth_accounts is what shows which site a request was credited to.
+// An origin with no host names no site, so its request is refused
+// (https://git.eeqj.de/sneak/AutistMask/issues/527). The browser reports
+// "null" for a page with an opaque origin, such as one its server sandboxes
+// with a Content-Security-Policy, and Chrome reports "file://" for a local
+// file.
+//
+// Every other sender here lacks sender.origin, as on old Firefox. The
+// connection check on eth_accounts is what shows which site a request was
+// credited to.
 
 const { makeStorageStub } = require("./support/storageStub");
 
@@ -144,3 +151,41 @@ describe("a request the browser does not say the sender of", () => {
         });
     });
 });
+
+describe("a request whose origin has no host", () => {
+    test("from a page with an opaque origin is refused, whatever its URL says", async () => {
+        const accounts = loadBackground();
+
+        const result = await accounts({
+            origin: "null",
+            url: CONNECTED_ORIGIN + "/sandboxed.html",
+            tab: { url: CONNECTED_ORIGIN + "/sandboxed.html" },
+        });
+
+        expect(result).toEqual({
+            error: {
+                code: 4100,
+                message:
+                    "The wallet could not tell which site sent this request.",
+            },
+        });
+    });
+
+    test("from a local file is refused", async () => {
+        const accounts = loadBackground();
+
+        const result = await accounts({
+            origin: "file://",
+            url: "file:///home/user/page.html",
+            tab: { url: "file:///home/user/page.html" },
+        });
+
+        expect(result).toEqual({
+            error: {
+                code: 4100,
+                message:
+                    "The wallet could not tell which site sent this request.",
+            },
+        });
+    });
+});

tests/sendAmountRule.test.js

@@ -0,0 +1,213 @@
+// The Send screen refuses every amount the confirmation screen would refuse,
+// by the same check (https://git.eeqj.de/sneak/AutistMask/issues/532).
+//
+// Send used to accept anything parseFloat() read as above zero, so "1e-3",
+// "1abc" and an amount with more decimal places than the token has went on to
+// a confirmation screen that then refused them. Both screens now call
+// isValidAmount() in src/shared/txValidation.js.
+//
+// Driven through the real Send review handler and the real confirmation
+// screen, with only the node and the DOM stubbed.
+
+"use strict";
+
+jest.mock("../src/shared/log", () => ({
+    log: {
+        debugf: () => {},
+        infof: () => {},
+        warnf: () => {},
+        errorf: () => {},
+    },
+    debugFetch: jest.fn(),
+    setRuntimeDebug: () => {},
+    isDebug: () => false,
+}));
+
+// What the confirmation screen asks the node for.
+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 Etherscan label lookup fails, as it does offline.
+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 resolves to a recording element.
+const elements = new Map();
+
+function makeEl(id) {
+    const handlers = new Map();
+    return {
+        id,
+        textContent: "",
+        innerHTML: "",
+        value: "",
+        disabled: false,
+        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 { state } = require("../src/shared/state");
+const send = require("../src/popup/views/send");
+const confirmTx = require("../src/popup/views/confirmTx");
+
+const HOLDER = "0x" + "a".repeat(40);
+const RECIPIENT = "0xC0FfEE0000000000000000000000000000c0fFEe";
+// A token with 6 decimal places, as USDC has.
+const TOKEN = "0x" + "d".repeat(40);
+const TOKEN_BY_SYMBOL = { ETH: "ETH", TOK: TOKEN };
+
+function el(id) {
+    return global.document.getElementById(id);
+}
+
+// Press Review on the Send screen with `amount` entered, for a send of `token`
+// ("ETH" or TOKEN), and return what it handed the confirmation screen, or null
+// when it handed nothing over.
+async function review(amount, token) {
+    let handed = null;
+    send.init({ showConfirmTx: (info) => (handed = info) });
+    state.selectedToken = token;
+    el("send-to").value = RECIPIENT;
+    el("send-amount").value = amount;
+    await el("btn-send-review").handlers.get("click")();
+    return handed;
+}
+
+// Show the confirmation screen for the send Review hands over for 0.5, with
+// `amount` in its place, and let its fee estimate settle.
+async function confirm(amount, token) {
+    const txInfo = await review("0.5", token);
+    confirmTx.show({ ...txInfo, amount });
+    for (let i = 0; i < 10; i++) await new Promise((r) => setTimeout(r, 0));
+}
+
+beforeEach(() => {
+    elements.clear();
+    state.wallets = [
+        {
+            name: "Wallet 1",
+            addresses: [
+                {
+                    address: HOLDER,
+                    balance: "1.0",
+                    tokenBalances: [
+                        {
+                            address: TOKEN,
+                            name: "Token",
+                            symbol: "TOK",
+                            decimals: 6,
+                            balance: "250.0",
+                            holders: 50000,
+                        },
+                    ],
+                },
+            ],
+        },
+    ];
+    state.selectedWallet = 0;
+    state.selectedAddress = 0;
+    state.trackedTokens = [
+        { address: TOKEN, symbol: "TOK", name: "Token", decimals: 6 },
+    ];
+    state.fraudContracts = [];
+    state.selectedToken = null;
+    state.currentView = null;
+});
+
+describe.each([
+    ["1e-3", "ETH"],
+    ["1e-3", "TOK"],
+    ["1abc", "ETH"],
+    // 19 decimal places; ETH has 18.
+    ["0.0000000000000000001", "ETH"],
+    // 7 decimal places; the token has 6.
+    ["0.0000001", "TOK"],
+    ["0", "ETH"],
+    ["-1", "ETH"],
+])("%s %s", (amount, symbol) => {
+    const token = TOKEN_BY_SYMBOL[symbol];
+
+    test("Send refuses it with a flash message and opens nothing", async () => {
+        expect(await review(amount, token)).toBe(null);
+        expect(el("flash-msg").textContent).toBe(
+            "Please enter a valid amount.",
+        );
+    });
+
+    test("the confirmation screen refuses it too", async () => {
+        await confirm(amount, token);
+        expect(el("confirm-errors").innerHTML).toContain(
+            "Please enter a valid amount to send.",
+        );
+        expect(el("btn-confirm-send").disabled).toBe(true);
+    });
+});
+
+describe.each([
+    ["0.5", "ETH"],
+    ["0.5", "TOK"],
+    // Exactly the 6 decimal places the token has.
+    ["0.000001", "TOK"],
+    // Only zeros past the token's 6 places, and past ETH's 18.
+    ["1.0000000", "TOK"],
+    ["0.5000000000000000000", "ETH"],
+])("%s %s", (amount, symbol) => {
+    const token = TOKEN_BY_SYMBOL[symbol];
+
+    test("Send hands it to the confirmation screen", async () => {
+        expect((await review(amount, token)).amount).toBe(amount);
+        expect(el("flash-msg").textContent).toBe("");
+    });
+
+    test("the confirmation screen lets it be sent", async () => {
+        await confirm(amount, token);
+        expect(el("confirm-errors").innerHTML).toBe("");
+        expect(el("btn-confirm-send").disabled).toBe(false);
+    });
+});

tests/support/popupBoot.js

@@ -242,6 +242,13 @@ async function settle() {
  *     "?approval=" and an id for the popup opened as an approval window.
  * @param {object} [options.runtime] members of chrome.runtime that replace the
  *     stub's own, for a test that has to answer the background's messages.
+ * @param {object} [options.windows] chrome.windows, for a test of the approval
+ *     window resizing itself.
+ * @param {object} [options.tabs] chrome.tabs, for the same test: the page's
+ *     tab and its zoom.
+ * @param {object} [options.documentElement] members of document.documentElement
+ *     that replace the stub's own: scrollWidth and clientWidth, which are equal
+ *     unless a test says otherwise, so the page does not scroll sideways.
  * @returns {Promise<object>} handles onto the booted page.
  */
 async function bootPopup(stored, options) {
@@ -258,12 +265,17 @@ async function bootPopup(stored, options) {
         formatAddressTotal: () => "",
         getAddressValue: () => ({ usd: null, partial: false }),
     }));
+    // scanForAddresses() answers in the real one's shape, a scan that found
+    // no used address: AddWallet reads `addresses` from it.
     jest.doMock("../../src/shared/balances", () => ({
         fetchTokenBalances: jest.fn(async () => []),
         refreshBalances: jest.fn(async () => {}),
         lookupTokenInfo: jest.fn(async () => null),
         getProvider: () => ({}),
-        scanForAddresses: jest.fn(async () => []),
+        scanForAddresses: jest.fn(async () => ({
+            addresses: [],
+            nextIndex: 1,
+        })),
     }));
     // filterTransactions() answers in the real one's shape: Home,
     // AddressDetail and AddressToken read both fields, and a bare list makes
@@ -277,7 +289,13 @@ async function bootPopup(stored, options) {
         (options && options.storage) ||
         makeStorageStub(stored === undefined ? {} : { autistmask: stored });
     const document = makeDocument(POPUP_HTML);
+    Object.assign(
+        document.documentElement,
+        { scrollWidth: 396, clientWidth: 396 },
+        options && options.documentElement,
+    );
     const reloads = [];
+    const windowListeners = {};
 
     globalThis.chrome = {
         storage: { local: storage.local },
@@ -287,6 +305,8 @@ async function bootPopup(stored, options) {
             onMessage: { addListener: () => {} },
             ...(options && options.runtime),
         },
+        windows: options && options.windows,
+        tabs: options && options.tabs,
     };
     globalThis.document = document;
     globalThis.window = {
@@ -300,7 +320,13 @@ async function bootPopup(stored, options) {
             addEventListener: () => {},
             removeEventListener: () => {},
         }),
-        addEventListener: () => {},
+        // Recorded, as the document's are, so a test that widens the approval
+        // window can call the page's resize listeners.
+        listeners: windowListeners,
+        addEventListener: (name, fn) => {
+            windowListeners[name] = windowListeners[name] || [];
+            windowListeners[name].push(fn);
+        },
     };
     // The ten-second refresh init() starts, and a transaction wait's timers,
     // would outlive the test. So every interval is recorded rather than

tests/support/storageStub.js

@@ -1,4 +1,4 @@
-// A chrome.storage.local stub that behaves like the real one.
+// A chrome.storage stub that behaves like the real one.
 //
 // The real extension storage API is a serialization boundary: `set` writes a
 // structured clone of what it is given, and `get` hands back a structured
@@ -17,13 +17,8 @@
 // So every test that drives real persistence uses this, and nothing rebuilds
 // a storage stub by hand.
 
-// `initial` is the starting contents, keyed as storage is: { autistmask: {...} }.
-// `onOp` runs before each operation, for a test that needs to advance a clock
-// or count round trips.
-function makeStorageStub(initial, onOp) {
-    const store = initial ? structuredClone(initial) : {};
-    const tick = onOp || (() => {});
-
+// One storage area: get, set and remove over its own store, cloning both ways.
+function makeArea(store, tick) {
     const get = jest.fn(async (key) => {
         tick();
         if (key === undefined || key === null) return structuredClone(store);
@@ -49,15 +44,28 @@ function makeStorageStub(initial, onOp) {
         for (const k of Array.isArray(key) ? key : [key]) delete store[k];
     });
 
+    return { get, set, remove };
+}
+
+// `initial` is the starting contents of `storage.local`, keyed as storage is:
+// { autistmask: {...} }. `storage.session` starts empty.
+// `onOp` runs before each operation on either area, for a test that needs to
+// advance a clock or count round trips.
+function makeStorageStub(initial, onOp) {
+    const store = initial ? structuredClone(initial) : {};
+    const tick = onOp || (() => {});
+    const local = makeArea(store, tick);
+
     return {
         // Drop this straight in as chrome.storage.
-        local: { get, set, remove },
-        get,
-        set,
-        remove,
-        // What is stored, cloned on the way out: a test can neither observe a
-        // later write through an object it read nor reach into the store by
-        // mutating one.
+        local,
+        session: makeArea({}, tick),
+        get: local.get,
+        set: local.set,
+        remove: local.remove,
+        // What is stored in `storage.local`, cloned on the way out: a test can
+        // neither observe a later write through an object it read nor reach
+        // into the store by mutating one.
         read: (key) =>
             key === undefined
                 ? structuredClone(store)

tests/transferAmount.test.js

@@ -116,6 +116,12 @@ describe("transferAmountUnits", () => {
         expect(() => transferAmountUnits("0.0000001", 6, 6n)).toThrow();
     });
 
+    test("encodes zeros past the token's scale as the amount typed", () => {
+        // The Send screen accepts "1.0000000" for a 6-place token, so the
+        // transfer must move exactly 1 of it.
+        expect(transferAmountUnits("1.0000000", 6, 6n)).toBe(1000000n);
+    });
+
     test("every refusal is a full sentence", () => {
         const messages = [];
         for (const args of [

tests/txValidation.test.js

@@ -6,6 +6,7 @@ const {
     FEE_UNAVAILABLE,
     feeReserveWei,
     feeEstimateWei,
+    isValidAmount,
     maxEthAmount,
     maxTokenAmount,
     toFixedPoint,
@@ -33,6 +34,49 @@ describe("toFixedPoint", () => {
     });
 });
 
+// The one amount check the Send screen and the confirmation screen share.
+// The screens themselves are driven in tests/sendAmountRule.test.js.
+describe("isValidAmount", () => {
+    test("accepts a number above zero written as digits and a decimal point", () => {
+        expect(isValidAmount("0.5")).toBe(true);
+        expect(isValidAmount("12")).toBe(true);
+        expect(isValidAmount(".5")).toBe(true);
+        expect(isValidAmount("0.000000000000000001")).toBe(true);
+    });
+
+    test("refuses an exponent, trailing text, zero and a negative amount", () => {
+        expect(isValidAmount("1e-3")).toBe(false);
+        expect(isValidAmount("1abc")).toBe(false);
+        expect(isValidAmount("0")).toBe(false);
+        expect(isValidAmount("0.0")).toBe(false);
+        expect(isValidAmount("-1")).toBe(false);
+        expect(isValidAmount("")).toBe(false);
+        expect(isValidAmount(undefined)).toBe(false);
+    });
+
+    test("refuses a digit other than 0 past the token's places", () => {
+        expect(isValidAmount("0.000001", 6)).toBe(true);
+        expect(isValidAmount("0.0000001", 6)).toBe(false);
+        expect(isValidAmount("5", 0)).toBe(true);
+        expect(isValidAmount("0.5", 0)).toBe(false);
+    });
+
+    test("accepts zeros past the token's places, which leave the amount unchanged", () => {
+        expect(isValidAmount("1.0000000", 6)).toBe(true);
+        expect(isValidAmount("5.0", 0)).toBe(true);
+        expect(isValidAmount("1.0000000000000000000")).toBe(true);
+        expect(isValidAmount("0.0000000", 6)).toBe(false);
+    });
+
+    test("holds ETH, a token of unknown places, and any token to 18 places", () => {
+        const nineteen = "0.0000000000000000001";
+        expect(isValidAmount(nineteen)).toBe(false);
+        expect(isValidAmount(nineteen, null)).toBe(false);
+        expect(isValidAmount(nineteen, 24)).toBe(false);
+        expect(isValidAmount("0.000000000000000001", 24)).toBe(true);
+    });
+});
+
 describe("validateTransfer, native ETH", () => {
     const eth = (over) => ({
         isErc20: false,
@@ -134,6 +178,17 @@ describe("validateTransfer, native ETH", () => {
         ).toEqual({ canSend: false, codes: [CODES.AMOUNT_INVALID] });
     });
 
+    test("rejects a zero amount and an exponent", () => {
+        expect(validateTransfer(eth({ amount: "0" }))).toEqual({
+            canSend: false,
+            codes: [CODES.AMOUNT_INVALID],
+        });
+        expect(validateTransfer(eth({ amount: "1e-3" }))).toEqual({
+            canSend: false,
+            codes: [CODES.AMOUNT_INVALID],
+        });
+    });
+
     test("treats a missing balance as zero, not as unlimited", () => {
         const r = validateTransfer(eth({ ethBalance: undefined }));
         expect(r.codes).toEqual([CODES.INSUFFICIENT_ETH]);
@@ -205,6 +260,16 @@ describe("validateTransfer, ERC-20", () => {
         expect(r).toEqual({ canSend: false, codes: [CODES.AMOUNT_INVALID] });
     });
 
+    test("rejects more decimal places than the token has", () => {
+        const r = validateTransfer(
+            erc20({ amount: "0.0000001", tokenDecimals: 6 }),
+        );
+        expect(r).toEqual({ canSend: false, codes: [CODES.AMOUNT_INVALID] });
+        expect(
+            validateTransfer(erc20({ amount: "0.000001", tokenDecimals: 6 })),
+        ).toEqual({ canSend: true, codes: [] });
+    });
+
     test("treats a missing token balance as zero", () => {
         const r = validateTransfer(erc20({ tokenBalance: undefined }));
         expect(r.codes).toEqual([CODES.INSUFFICIENT_TOKEN]);

tests/uniswap.test.js

@@ -107,6 +107,7 @@ function encodeV4Swap(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_SWAP_EXACT_OUT_SINGLE_ID = 0x08;
 const V4_SETTLE_ID = 0x0b;
 const V4_TAKE_ID = 0x0e;
 const ZERO_ADDR = "0x0000000000000000000000000000000000000000";
@@ -163,6 +164,31 @@ function encodeV4ExactInSingle(currency0, currency1, amountIn, amountOutMin) {
     );
 }
 
+// Helper: V4 ExactOutputSingleParams —
+//   (tuple(address,address,uint24,int24,address) poolKey, bool zeroForOne,
+//    uint128 amountOut, uint128 amountInMaximum, bytes hookData)
+function encodeV4ExactOutSingle(
+    currency0,
+    currency1,
+    amountOut,
+    amountInMaximum,
+) {
+    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
+                amountOut,
+                amountInMaximum,
+                "0x",
+            ],
+        ],
+    );
+}
+
 // Each V4 swap action's parameters in two shapes: the struct V4Router has
 // deployed on mainnet and Sepolia, and the one v4-periphery `main` has since
 // moved to, which adds a `minHopPriceX36` field. Each swaps WETH for USDC.
@@ -267,9 +293,7 @@ function v4SwapCalldata(actionId, swapParams) {
     );
 }
 
-// V4 SETTLE_ALL (currency, maxAmount) and TAKE_ALL (currency, minAmount). The
-// decoder reads neither, so in a V4_SWAP of a swap action and these, only the
-// swap action names the currencies.
+// V4 SETTLE_ALL (currency, maxAmount) and TAKE_ALL (currency, minAmount).
 const V4_SETTLE_ALL_ID = 0x0c;
 const V4_TAKE_ALL_ID = 0x0f;
 function encodeV4SettleAll(currency, maxAmount) {
@@ -279,6 +303,12 @@ function encodeV4TakeAll(currency, minAmount) {
     return coder.encode(["address", "uint256"], [currency, minAmount]);
 }
 
+// V4 CLOSE_CURRENCY (currency), which the decoder does not read.
+const V4_CLOSE_CURRENCY_ID = 0x12;
+function encodeV4CloseCurrency(currency) {
+    return coder.encode(["address"], [currency]);
+}
+
 function detail(result, label) {
     return result.details.find((d) => d.label === label);
 }
@@ -358,10 +388,9 @@ describe("uniswap decoder", () => {
         },
     );
 
-    // Only the unread swap action names the currencies here. The token lines
-    // must not say the calldata did not name them.
+    // SETTLE_ALL and TAKE_ALL name both sides as SETTLE and TAKE do.
     test.each(V4_SWAP_ACTION_SHAPES)(
-        "a V4 $action in the newer shape, then SETTLE_ALL and TAKE_ALL, says both tokens could not be decoded",
+        "a V4 $action in the newer shape, then SETTLE_ALL and TAKE_ALL, takes both tokens from them",
         ({ id, newer }) => {
             const data = buildExecute(
                 "0x10",
@@ -381,6 +410,27 @@ describe("uniswap decoder", () => {
             expect(detail(result, "Steps").value).toBe(
                 "V4 Swap (could not be decoded)",
             );
+            expect(detail(result, "Token In").address).toBe(WETH_ADDR);
+            expect(detail(result, "Token Out").address).toBe(USDC_ADDR);
+            expect(detail(result, "Amount")).toBeUndefined();
+            expect(detail(result, "Min. received")).toBeUndefined();
+        },
+    );
+
+    // Only the unread swap action names the currencies here. The token lines
+    // must not say the calldata did not name them.
+    test.each(V4_SWAP_ACTION_SHAPES)(
+        "a V4 step of only a $action in the newer shape says both tokens could not be decoded",
+        ({ id, newer }) => {
+            const data = buildExecute(
+                "0x10",
+                [encodeV4Swap(new Uint8Array([id]), [newer])],
+                9999999999n,
+            );
+            const result = uniswap.decode(data, ROUTER_ADDR);
+            expect(detail(result, "Steps").value).toBe(
+                "V4 Swap (could not be decoded)",
+            );
             expect(detail(result, "Token In").value).toBe(
                 "Unknown (could not be decoded)",
             );
@@ -394,7 +444,7 @@ describe("uniswap decoder", () => {
     // action names. The V3 step's WETH and its Min. received figure were
     // shown instead.
     test.each(V4_SWAP_ACTION_SHAPES)(
-        "a V3 step, then a V4 $action in the newer shape and TAKE_ALL, does not show the V3 step's output",
+        "a V3 step, then a V4 step of only a $action in the newer shape, does not show the V3 step's output",
         ({ id, newer }) => {
             const data = buildExecute(
                 solidityPacked(["uint8", "uint8"], [0x00, 0x10]),
@@ -403,10 +453,7 @@ describe("uniswap decoder", () => {
                         USDT_ADDR,
                         WETH_ADDR,
                     ]),
-                    encodeV4Swap(new Uint8Array([id, V4_TAKE_ALL_ID]), [
-                        newer,
-                        encodeV4TakeAll(USDC_ADDR, 990000n),
-                    ]),
+                    encodeV4Swap(new Uint8Array([id]), [newer]),
                 ],
                 9999999999n,
             );
@@ -423,15 +470,12 @@ describe("uniswap decoder", () => {
     // The user pays the V4 step's WETH, which only its unread swap action
     // names. The V3 step's USDC and its amount were shown instead.
     test.each(V4_SWAP_ACTION_SHAPES)(
-        "a V4 $action in the newer shape and SETTLE_ALL, then a V3 step, does not show the V3 step's input",
+        "a V4 step of only a $action in the newer shape, then a V3 step, does not show the V3 step's input",
         ({ id, newer }) => {
             const data = buildExecute(
                 solidityPacked(["uint8", "uint8"], [0x10, 0x00]),
                 [
-                    encodeV4Swap(new Uint8Array([id, V4_SETTLE_ALL_ID]), [
-                        newer,
-                        encodeV4SettleAll(WETH_ADDR, ONE_WETH),
-                    ]),
+                    encodeV4Swap(new Uint8Array([id]), [newer]),
                     encodeV3SwapExactIn(
                         USER_ADDR,
                         990000n,
@@ -458,10 +502,7 @@ describe("uniswap decoder", () => {
         const data = buildExecute(
             solidityPacked(["uint8", "uint8"], [0x10, 0x0c]),
             [
-                encodeV4Swap(new Uint8Array([id, V4_TAKE_ALL_ID]), [
-                    newer,
-                    encodeV4TakeAll(USDC_ADDR, 990000n),
-                ]),
+                encodeV4Swap(new Uint8Array([id]), [newer]),
                 encodeWrapEth(USER_ADDR, 0n), // UNWRAP_WETH, same encoding
             ],
             9999999999n,
@@ -1124,6 +1165,419 @@ describe("uniswap decoder", () => {
         expect(detail(result, "Min. received").value).toBe("0.9900 USDC");
     });
 
+    // https://git.eeqj.de/sneak/AutistMask/issues/563 — a V4 step of several
+    // swap actions. The screen showed the first action's output as Token Out.
+    // Every step below pays USDT and receives USDC, so it reads Swap USDT →
+    // USDC whichever kind of swap actions it holds and in whatever order they
+    // are written. Each is tried with three endings: SETTLE_ALL and TAKE_ALL,
+    // SETTLE and TAKE, and CLOSE_CURRENCY for each currency, which leaves the
+    // sides to the swap actions alone.
+    const V4_STEP_ENDINGS = [
+        {
+            ending: "SETTLE_ALL and TAKE_ALL",
+            ids: [V4_SETTLE_ALL_ID, V4_TAKE_ALL_ID],
+            params: [
+                encodeV4SettleAll(USDT_ADDR, 1000000000n),
+                encodeV4TakeAll(USDC_ADDR, 990000000n),
+            ],
+        },
+        {
+            ending: "SETTLE and TAKE",
+            ids: [V4_SETTLE_ID, V4_TAKE_ID],
+            params: [encodeV4Settle(USDT_ADDR), encodeV4Take(USDC_ADDR)],
+        },
+        {
+            ending: "CLOSE_CURRENCY",
+            ids: [
+                V4_CLOSE_CURRENCY_ID,
+                V4_CLOSE_CURRENCY_ID,
+                V4_CLOSE_CURRENCY_ID,
+            ],
+            params: [
+                encodeV4CloseCurrency(USDT_ADDR),
+                encodeV4CloseCurrency(WETH_ADDR),
+                encodeV4CloseCurrency(USDC_ADDR),
+            ],
+        },
+    ];
+    // 1,000 USDT for at least 0.5 WETH
+    const USDT_FOR_WETH_IN = {
+        id: V4_SWAP_EXACT_IN_SINGLE_ID,
+        param: encodeV4ExactInSingle(
+            USDT_ADDR,
+            WETH_ADDR,
+            1000000000n,
+            500000000000000000n,
+        ),
+    };
+    // 0.5 WETH for at least 990 USDC
+    const WETH_FOR_USDC_IN = {
+        id: V4_SWAP_EXACT_IN_SINGLE_ID,
+        param: encodeV4ExactInSingle(
+            WETH_ADDR,
+            USDC_ADDR,
+            500000000000000000n,
+            990000000n,
+        ),
+    };
+    // exactly 0.5 WETH for at most 1,000 USDT
+    const USDT_FOR_WETH_OUT = {
+        id: V4_SWAP_EXACT_OUT_SINGLE_ID,
+        param: encodeV4ExactOutSingle(
+            USDT_ADDR,
+            WETH_ADDR,
+            500000000000000000n,
+            1000000000n,
+        ),
+    };
+    // exactly 990 USDC for at most 0.5 WETH
+    const WETH_FOR_USDC_OUT = {
+        id: V4_SWAP_EXACT_OUT_SINGLE_ID,
+        param: encodeV4ExactOutSingle(
+            WETH_ADDR,
+            USDC_ADDR,
+            990000000n,
+            500000000000000000n,
+        ),
+    };
+    // 400 USDT for at least 396 USDC
+    const USDT_FOR_USDC_IN = {
+        id: V4_SWAP_EXACT_IN_SINGLE_ID,
+        param: encodeV4ExactInSingle(
+            USDT_ADDR,
+            USDC_ADDR,
+            400000000n,
+            396000000n,
+        ),
+    };
+    // 600 USDT through WETH for at least 594 USDC
+    const USDT_FOR_USDC_THROUGH_WETH_IN = {
+        id: V4_SWAP_EXACT_IN,
+        param: encodeV4ExactIn(
+            USDT_ADDR,
+            [WETH_ADDR, USDC_ADDR],
+            600000000n,
+            594000000n,
+        ),
+    };
+    // the open delta of USDT through WETH for at least 594 USDC
+    const USDT_OPEN_DELTA_FOR_USDC_THROUGH_WETH_IN = {
+        id: V4_SWAP_EXACT_IN,
+        param: encodeV4ExactIn(
+            USDT_ADDR,
+            [WETH_ADDR, USDC_ADDR],
+            0n,
+            594000000n,
+        ),
+    };
+    // Amount is the amountIn of the action that spends USDT, or the sum when
+    // several exact-in actions each state one. Min. received is the same for
+    // the actions that buy USDC. The decoder reads no amount from an exact-out
+    // action, and an open delta is not a stated amount.
+    const V4_STEPS = [
+        {
+            step: "USDT for WETH exact-in, then WETH for USDC exact-in",
+            swaps: [USDT_FOR_WETH_IN, WETH_FOR_USDC_IN],
+            amount: "1000.0000 USDT",
+            min: "990.0000 USDC",
+        },
+        {
+            step: "WETH for USDC exact-in, then USDT for WETH exact-in",
+            swaps: [WETH_FOR_USDC_IN, USDT_FOR_WETH_IN],
+            amount: "1000.0000 USDT",
+            min: "990.0000 USDC",
+        },
+        {
+            step: "WETH for USDC exact-out, then USDT for WETH exact-out",
+            swaps: [WETH_FOR_USDC_OUT, USDT_FOR_WETH_OUT],
+            amount: undefined,
+            min: undefined,
+        },
+        {
+            step: "USDT for WETH exact-out, then WETH for USDC exact-out",
+            swaps: [USDT_FOR_WETH_OUT, WETH_FOR_USDC_OUT],
+            amount: undefined,
+            min: undefined,
+        },
+        {
+            step: "USDT for WETH exact-in, then WETH for USDC exact-out",
+            swaps: [USDT_FOR_WETH_IN, WETH_FOR_USDC_OUT],
+            amount: "1000.0000 USDT",
+            min: undefined,
+        },
+        {
+            step: "WETH for USDC exact-out, then USDT for WETH exact-in",
+            swaps: [WETH_FOR_USDC_OUT, USDT_FOR_WETH_IN],
+            amount: "1000.0000 USDT",
+            min: undefined,
+        },
+        {
+            step: "USDT for WETH exact-out, then WETH for USDC exact-in",
+            swaps: [USDT_FOR_WETH_OUT, WETH_FOR_USDC_IN],
+            amount: undefined,
+            min: "990.0000 USDC",
+        },
+        {
+            step: "USDT for USDC, then USDT for USDC through WETH, both exact-in",
+            swaps: [USDT_FOR_USDC_IN, USDT_FOR_USDC_THROUGH_WETH_IN],
+            amount: "1000.0000 USDT",
+            min: "990.0000 USDC",
+        },
+        {
+            step: "USDT for USDC, then the open delta of USDT for USDC through WETH, both exact-in",
+            swaps: [USDT_FOR_USDC_IN, USDT_OPEN_DELTA_FOR_USDC_THROUGH_WETH_IN],
+            amount: undefined,
+            min: "990.0000 USDC",
+        },
+    ];
+    test.each(
+        V4_STEPS.flatMap((step) =>
+            V4_STEP_ENDINGS.map((ending) => ({ ...step, ...ending })),
+        ),
+    )(
+        "a V4 step of $step, then $ending, reads Swap USDT → USDC",
+        ({ swaps, ids, params, amount, min }) => {
+            const data = buildExecute(
+                "0x10",
+                [
+                    encodeV4Swap(
+                        new Uint8Array([...swaps.map((s) => s.id), ...ids]),
+                        [...swaps.map((s) => s.param), ...params],
+                    ),
+                ],
+                9999999999n,
+            );
+
+            const result = uniswap.decode(data, ROUTER_ADDR);
+            expect(result.name).toBe("Swap USDT → USDC");
+            expect(detail(result, "Token In").address).toBe(USDT_ADDR);
+            expect(detail(result, "Token Out").address).toBe(USDC_ADDR);
+            expect(detail(result, "Amount")?.value).toBe(amount);
+            expect(detail(result, "Min. received")?.value).toBe(min);
+        },
+    );
+
+    // A step with a swap action that could not be read is named only by its
+    // SETTLE_ALL, TAKE_ALL, SETTLE and TAKE, and states no figure: its readable
+    // USDT for WETH action names neither side. The unread action is
+    // V4_SWAP_ACTION_SHAPES[0].newer, WETH for USDC exact-in in the newer
+    // shape.
+    test.each([
+        {
+            ...V4_STEP_ENDINGS[0],
+            tokenIn: `USDT (${USDT_ADDR})`,
+            tokenOut: `USDC (${USDC_ADDR})`,
+        },
+        {
+            ...V4_STEP_ENDINGS[1],
+            tokenIn: `USDT (${USDT_ADDR})`,
+            tokenOut: `USDC (${USDC_ADDR})`,
+        },
+        {
+            ...V4_STEP_ENDINGS[2],
+            tokenIn: "Unknown (could not be decoded)",
+            tokenOut: "Unknown (could not be decoded)",
+        },
+    ])(
+        "a V4 step of a readable swap action and an unread one, then $ending, shows no figure",
+        ({ ids, params, tokenIn, tokenOut }) => {
+            const data = buildExecute(
+                "0x10",
+                [
+                    encodeV4Swap(
+                        new Uint8Array([
+                            USDT_FOR_WETH_IN.id,
+                            V4_SWAP_ACTION_SHAPES[0].id,
+                            ...ids,
+                        ]),
+                        [
+                            USDT_FOR_WETH_IN.param,
+                            V4_SWAP_ACTION_SHAPES[0].newer,
+                            ...params,
+                        ],
+                    ),
+                ],
+                9999999999n,
+            );
+
+            const result = uniswap.decode(data, ROUTER_ADDR);
+            expect(detail(result, "Steps").value).toBe(
+                "V4 Swap (could not be decoded)",
+            );
+            expect(detail(result, "Token In").value).toBe(tokenIn);
+            expect(detail(result, "Token Out").value).toBe(tokenOut);
+            expect(detail(result, "Amount")).toBeUndefined();
+            expect(detail(result, "Min. received")).toBeUndefined();
+        },
+    );
+
+    // A V4 step that spends WETH on USDC and on DAI. Its swap actions buy two
+    // currencies that none of them spends, and CLOSE_CURRENCY, which the
+    // decoder does not read, names no side, so its output side is unknown.
+    const WETH_FOR_USDC_AND_DAI = encodeV4Swap(
+        new Uint8Array([
+            V4_SWAP_EXACT_IN_SINGLE_ID,
+            V4_SWAP_EXACT_IN_SINGLE_ID,
+            V4_CLOSE_CURRENCY_ID,
+            V4_CLOSE_CURRENCY_ID,
+            V4_CLOSE_CURRENCY_ID,
+        ]),
+        [
+            // 0.25 WETH for at least 495 USDC
+            encodeV4ExactInSingle(
+                WETH_ADDR,
+                USDC_ADDR,
+                250000000000000000n,
+                495000000n,
+            ),
+            // 0.25 WETH for at least 495 DAI
+            encodeV4ExactInSingle(
+                WETH_ADDR,
+                DAI_ADDR,
+                250000000000000000n,
+                495000000000000000000n,
+            ),
+            encodeV4CloseCurrency(WETH_ADDR),
+            encodeV4CloseCurrency(USDC_ADDR),
+            encodeV4CloseCurrency(DAI_ADDR),
+        ],
+    );
+
+    // The user ends with USDC and DAI, not the V3 step's WETH. That WETH and
+    // the V3 step's Min. received figure were shown instead.
+    test("a V3 step, then a V4 step whose swap actions buy two currencies, does not show the V3 step's output", () => {
+        const data = buildExecute(
+            solidityPacked(["uint8", "uint8"], [0x00, 0x10]),
+            [
+                encodeV3SwapExactIn(
+                    USER_ADDR,
+                    1000000000n,
+                    500000000000000000n,
+                    [USDT_ADDR, WETH_ADDR],
+                ),
+                WETH_FOR_USDC_AND_DAI,
+            ],
+            9999999999n,
+        );
+        const result = uniswap.decode(data, ROUTER_ADDR);
+        expect(result.name).toBe("Uniswap Swap");
+        expect(detail(result, "Token In").address).toBe(
+            USDT_ADDR.toLowerCase(),
+        );
+        expect(detail(result, "Amount").value).toBe("1000.0000 USDT");
+        expect(detail(result, "Token Out").value).toBe(
+            "Unknown (not named in the calldata)",
+        );
+        expect(detail(result, "Min. received")).toBeUndefined();
+    });
+
+    // The input side of the same gap: the V4 step's swap actions spend USDC
+    // and DAI, two currencies that none of them buys, and nothing names its
+    // input side. The V3 step's WETH and its amount were shown instead.
+    test("a V4 step whose swap actions spend two currencies, then a V3 step, does not show the V3 step's input", () => {
+        const data = buildExecute(
+            solidityPacked(["uint8", "uint8"], [0x10, 0x00]),
+            [
+                encodeV4Swap(
+                    new Uint8Array([
+                        V4_SWAP_EXACT_IN_SINGLE_ID,
+                        V4_SWAP_EXACT_IN_SINGLE_ID,
+                        V4_CLOSE_CURRENCY_ID,
+                        V4_CLOSE_CURRENCY_ID,
+                        V4_CLOSE_CURRENCY_ID,
+                    ]),
+                    [
+                        // 500 USDC for at least 0.25 WETH
+                        encodeV4ExactInSingle(
+                            USDC_ADDR,
+                            WETH_ADDR,
+                            500000000n,
+                            250000000000000000n,
+                        ),
+                        // 500 DAI for at least 0.25 WETH
+                        encodeV4ExactInSingle(
+                            DAI_ADDR,
+                            WETH_ADDR,
+                            500000000000000000000n,
+                            250000000000000000n,
+                        ),
+                        encodeV4CloseCurrency(USDC_ADDR),
+                        encodeV4CloseCurrency(DAI_ADDR),
+                        encodeV4CloseCurrency(WETH_ADDR),
+                    ],
+                ),
+                encodeV3SwapExactIn(
+                    USER_ADDR,
+                    500000000000000000n,
+                    990000000n,
+                    [WETH_ADDR, USDT_ADDR],
+                ),
+            ],
+            9999999999n,
+        );
+        const result = uniswap.decode(data, ROUTER_ADDR);
+        expect(result.name).toBe("Uniswap Swap");
+        expect(detail(result, "Token In").value).toBe(
+            "Unknown (not named in the calldata)",
+        );
+        expect(detail(result, "Amount")).toBeUndefined();
+        expect(detail(result, "Token Out").address).toBe(
+            USDT_ADDR.toLowerCase(),
+        );
+        expect(detail(result, "Min. received").value).toBe("990.0000 USDT");
+    });
+
+    // UNWRAP_WETH makes Token Out ETH when no step set the output side. A V4
+    // step with a swap action did set it, to unknown here.
+    test("an UNWRAP_WETH after a V4 step whose swap actions buy two currencies does not make Token Out ETH", () => {
+        const data = buildExecute(
+            solidityPacked(["uint8", "uint8"], [0x10, 0x0c]),
+            [
+                WETH_FOR_USDC_AND_DAI,
+                encodeWrapEth(USER_ADDR, 0n), // UNWRAP_WETH, same encoding
+            ],
+            9999999999n,
+        );
+        const result = uniswap.decode(data, ROUTER_ADDR);
+        expect(detail(result, "Token Out").value).toBe(
+            "Unknown (not named in the calldata)",
+        );
+    });
+
+    // The router works through an exact-out path from its last entry back to
+    // its first: the WETH entry buys the USDC, then the USDT entry buys that
+    // WETH. The user pays the first entry's USDT, not the last entry's WETH.
+    test("a two-hop V4 exact-out action shows its first path entry as Token In", () => {
+        const data = buildExecute(
+            "0x10",
+            [
+                encodeV4Swap(new Uint8Array([0x09]), [
+                    // SWAP_EXACT_OUT: exactly 990 USDC for at most 1,000 USDT
+                    coder.encode(
+                        [`tuple(address,${PATH_KEY}[],uint128,uint128)`],
+                        [
+                            [
+                                USDC_ADDR,
+                                [
+                                    [USDT_ADDR, 100, 1, ZERO_ADDR, "0x"],
+                                    [WETH_ADDR, 100, 1, ZERO_ADDR, "0x"],
+                                ],
+                                990000000n,
+                                1000000000n,
+                            ],
+                        ],
+                    ),
+                ]),
+            ],
+            9999999999n,
+        );
+
+        const result = uniswap.decode(data, ROUTER_ADDR);
+        expect(result.name).toBe("Swap USDT → USDC");
+        expect(detail(result, "Token In").address).toBe(USDT_ADDR);
+        expect(detail(result, "Token Out").address).toBe(USDC_ADDR);
+    });
+
     // https://git.eeqj.de/sneak/AutistMask/issues/415 — the router's V2
     // exact-in reads an amountIn of zero as universal-router
     // Constants.ALREADY_PAID: an earlier step sent the tokens to the pair, and