README.md

@@ -2368,9 +2368,10 @@ view would leave a wallet one click from deletion.
     - Site origin (bold, scheme and port included) + "wants to send a
       transaction"
     - Decoded action (if calldata is recognized): action name, token details,
-      amounts, steps, deadline, and unless a swap pays only the From address, a
-      `Paid to` line for each other address it pays, or saying that a token
-      stays in the router or who it pays is unknown (see Transaction Decoding)
+      amounts, what each `PERMIT2_TRANSFER_FROM` moves and where to, steps,
+      deadline, and unless a swap pays only the From address, a `Paid to` line
+      for each other address it pays, or saying that a token stays in the router
+      or who it pays is unknown (see Transaction Decoding)
     - From: color dot + full address + etherscan link
     - Contract: color dot + full address + etherscan link, token symbol label if
       known; for a contract creation, the same sentence as on WaitTx
@@ -3120,9 +3121,19 @@ Currently supported:
   name); and one more reads `Unknown (could not be decoded)` when a step that
   may pay an address went unread. When no step pays anyone, a single line reads
   `Unknown (not named in the calldata)`. Wherever there is a `Paid to` line, the
-  minimum reads `Min. paid out`. A step goes unread when its recipient does not
-  decode as an address, or when it is a command the decoder does not read: every
-  command other than `PERMIT2_PERMIT`, `PERMIT2_TRANSFER_FROM`,
+  minimum reads `Min. paid out`. After the `Amount` line (after `Token In` when
+  there is none), each `PERMIT2_TRANSFER_FROM` but one into the router, in step
+  order, gives three lines: `Moved from the sender`, the amount it moves, for
+  example `1000000.0000 USDT`; `Token moved`, giving the token's address as the
+  `Token In` line does; and `Moved to`, which reads
+  `The V2 pair the next swap spends` for a hop and `The sender` for `address(1)`
+  on every router but `UniversalRouterV1`, and otherwise gives the address. A
+  move into the router needs none of them, because its `Paid to` line and
+  `Token moved into the router` line already give the amount, the token and
+  where it goes, and so its amount is shown once. These lines change neither the
+  `Paid to` lines nor the minimum's label. A step goes unread when its recipient
+  does not decode as an address, or when it is a command the decoder does not
+  read: every command other than `PERMIT2_PERMIT`, `PERMIT2_TRANSFER_FROM`,
   `V2_SWAP_EXACT_IN`, `V2_SWAP_EXACT_OUT`, `V3_SWAP_EXACT_IN`, `V4_SWAP`,
   `SWEEP`, `TRANSFER`, `PAY_PORTION`, `PAY_PORTION_FULL_PRECISION`,
   `ACROSS_V4_DEPOSIT_V3`, `WRAP_ETH`, `UNWRAP_WETH` and `BALANCE_CHECK_ERC20`

src/shared/uniswap.js

@@ -488,6 +488,21 @@ function amountText(raw, info) {
     };
 }
 
+// The line giving a moved token under `label`, in the shape of the Token In
+// line, so the screens show it as they show that one. ETH has no address.
+function tokenMovedLine(label, token, sources) {
+    const info = tokenInfo(token, sources);
+    if (!present(info.address)) {
+        return { label, value: info.symbol };
+    }
+    return {
+        label,
+        value: info.symbol ? info.symbol + " (" + token + ")" : token,
+        address: token,
+        isToken: true,
+    };
+}
+
 // Decode PERMIT2_PERMIT (command 0x0a) input bytes.
 // ABI: ((address token, uint160 amount, uint48 expiration, uint48 nonce),
 //        address spender, uint256 sigDeadline), bytes signature
@@ -1171,6 +1186,13 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         // router, as { token, amount }. Later steps may leave part of it
         // there: nothing here checks that they spend all of it.
         const movedIntoRouter = [];
+        // What each PERMIT2_TRANSFER_FROM not into the router moves from the
+        // sender, in step order, whoever counts as paid, as
+        // { token, recipient, amount, to }: `to` says where it goes, the
+        // sender or the V2 pair the next swap spends, and is null when it
+        // goes to `recipient` as written. A move into the router is in
+        // `movedIntoRouter`, whose lines give its amount already.
+        const movedFromSender = [];
         // Each token a step paid to the router that no later step paid out
         // or spent in full, by its address, lowercased, ETH as the zero
         // address. The router is paid what a swap step, V4 TAKE or
@@ -1302,10 +1324,23 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                         // pays address(1) and address(2) as written (see
                         // decodePermit2TransferFrom()).
                         addPaidElsewhere(p.recipient);
+                        movedFromSender.push({ ...p, to: null });
                     } else if (isRouter(p.recipient)) {
                         movedIntoRouter.push(p);
-                    } else if (!isHop(i, p.token, p.recipient)) {
+                    } else if (isHop(i, p.token, p.recipient)) {
+                        movedFromSender.push({
+                            ...p,
+                            to: "The V2 pair the next swap spends",
+                        });
+                    } else {
                         addPayee(p.recipient);
+                        movedFromSender.push({
+                            ...p,
+                            to:
+                                p.recipient.toLowerCase() === MSG_SENDER
+                                    ? "The sender"
+                                    : null,
+                        });
                     }
                 } else if (command === "BALANCE_CHECK_ERC20") {
                     const b = decodeBalanceCheck(inputs[i]);
@@ -1675,6 +1710,26 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
             });
         }
 
+        // What each PERMIT2_TRANSFER_FROM moves: its amount, its token and
+        // where it goes, an address on a line of its own.
+        for (const m of movedFromSender) {
+            details.push({
+                label: "Moved from the sender",
+                value: amountText(m.amount, tokenInfo(m.token, sources))
+                    .display,
+            });
+            details.push(tokenMovedLine("Token moved", m.token, sources));
+            details.push(
+                present(m.to)
+                    ? { label: "Moved to", value: m.to }
+                    : {
+                          label: "Moved to",
+                          value: m.recipient,
+                          address: m.recipient,
+                      },
+            );
+        }
+
         // Keyed on the address, not the symbol: a token absent from the
         // bundled list has no symbol, and gating the line on one dropped it
         // entirely, leaving a Min. received figure with nothing saying what is
@@ -1723,24 +1778,6 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         if (bridgeDeposit) {
             paidTo.push({ label: "Paid to", value: PAID_TO_BRIDGE });
         }
-        // The line giving a token in the router, in the shape of the Token In
-        // line, so the screens show it as they show that one. ETH has no
-        // address.
-        const tokenMovedLine = (token) => {
-            const info = tokenInfo(token, sources);
-            if (!present(info.address)) {
-                return {
-                    label: "Token moved into the router",
-                    value: info.symbol,
-                };
-            }
-            return {
-                label: "Token moved into the router",
-                value: info.symbol ? info.symbol + " (" + token + ")" : token,
-                address: token,
-                isToken: true,
-            };
-        };
         for (const m of movedIntoRouter) {
             const info = tokenInfo(m.token, sources);
             paidTo.push({
@@ -1750,7 +1787,9 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                     amountText(m.amount, info).display +
                     " from the sender (later steps may not spend all of it)",
             });
-            paidTo.push(tokenMovedLine(m.token));
+            paidTo.push(
+                tokenMovedLine("Token moved into the router", m.token, sources),
+            );
         }
         if (outputHeld) {
             paidTo.push({ label: "Paid to", value: STAYS_IN_ROUTER });
@@ -1764,7 +1803,13 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                 continue;
             }
             paidTo.push({ label: "Paid to", value: STAYS_IN_ROUTER });
-            paidTo.push(tokenMovedLine(getAddress(token)));
+            paidTo.push(
+                tokenMovedLine(
+                    "Token moved into the router",
+                    getAddress(token),
+                    sources,
+                ),
+            );
         }
         if (payeeUnread) {
             paidTo.push({ label: "Paid to", value: UNDECODED_CURRENCY });

tests/uniswapRecipient.test.js

@@ -6,8 +6,10 @@
 // release runs for a command type
 // (https://git.eeqj.de/sneak/AutistMask/issues/592), the address whose
 // balance a BALANCE_CHECK_ERC20 checks
-// (https://git.eeqj.de/sneak/AutistMask/issues/600), and any token a swap
-// leaves in the router (https://git.eeqj.de/sneak/AutistMask/issues/606).
+// (https://git.eeqj.de/sneak/AutistMask/issues/600), any token a swap
+// leaves in the router (https://git.eeqj.de/sneak/AutistMask/issues/606), and
+// what each PERMIT2_TRANSFER_FROM moves
+// (https://git.eeqj.de/sneak/AutistMask/issues/611).
 //
 // Every swap command, SWEEP, WRAP_ETH, UNWRAP_WETH, TRANSFER, PAY_PORTION,
 // PAY_PORTION_FULL_PRECISION, PERMIT2_TRANSFER_FROM, ACROSS_V4_DEPOSIT_V3 and
@@ -349,6 +351,13 @@ const PAID_ELSEWHERE = [
     "Steps",
     "Deadline",
 ];
+// `lines` with the lines of one PERMIT2_TRANSFER_FROM after Amount.
+const withMove = (lines) =>
+    lines.flatMap((l) =>
+        l === "Amount"
+            ? [l, "Moved from the sender", "Token moved", "Moved to"]
+            : [l],
+    );
 
 // A swap of 2,000 USDT for at least 1 WETH, paid to `recipient`.
 const swapToWeth = (recipient) =>
@@ -1154,12 +1163,20 @@ describe("each transfer command's recipient", () => {
     test("PERMIT2_TRANSFER_FROM: to the user it pays no one else, to another address that address is named", () => {
         for (const r of [MSG_SENDER, USER]) {
             const result = decode(movedThenSwapped(r));
-            expect(labels(result)).toEqual(PAID_TO_USER);
+            expect(labels(result)).toEqual(withMove(PAID_TO_USER));
             expect(detail(result, "Min. received").value).toBe("1.0000 WETH");
         }
 
+        // A move to the From address as written shows that address, not The
+        // sender.
+        expect(detail(decode(movedThenSwapped(USER)), "Moved to")).toEqual({
+            label: "Moved to",
+            value: USER,
+            address: USER,
+        });
+
         const toOther = decode(movedThenSwapped(OTHER));
-        expect(labels(toOther)).toEqual(PAID_ELSEWHERE);
+        expect(labels(toOther)).toEqual(withMove(PAID_ELSEWHERE));
         expect(paidTo(toOther)).toEqual([OTHER]);
         expect(detail(toOther, "Min. paid out").value).toBe("1.0000 WETH");
 
@@ -1249,6 +1266,11 @@ describe("each transfer command's recipient", () => {
         for (const r of [MSG_SENDER, ADDRESS_THIS]) {
             const result = decode(movedThenSwapped(r), USER, ROUTER_V1);
             expect(paidTo(result)).toEqual([r]);
+            expect(detail(result, "Moved to")).toEqual({
+                label: "Moved to",
+                value: r,
+                address: r,
+            });
             expect(detail(result, "Min. received")).toBeUndefined();
         }
 
@@ -1294,6 +1316,112 @@ describe("each transfer command's recipient", () => {
     });
 });
 
+// https://git.eeqj.de/sneak/AutistMask/issues/611: after the swap's own
+// Amount, each PERMIT2_TRANSFER_FROM but one into the router gives the amount
+// of the sender's tokens it moves, the token, and where it goes, whoever
+// counts as paid.
+describe("what each PERMIT2_TRANSFER_FROM moves", () => {
+    // The WETH/USDC pair on Ethereum Mainnet, as its V2 factory reports it.
+    const PAIR = "0xB4e16d0168e52d35CaCD2c6185b44281Ec28C9Dc";
+    const USDT_1 = 1000000n;
+    const USDT_1000000 = 1000000000000n;
+
+    // The lines between Amount and Token Out.
+    function afterAmount(result) {
+        const all = labels(result);
+        return result.details.slice(
+            all.indexOf("Amount") + 1,
+            all.indexOf("Token Out"),
+        );
+    }
+    // The lines of a move of `amount` of `token`, then `to`.
+    const moved = (amount, token, symbol, to) => [
+        { label: "Moved from the sender", value: amount },
+        {
+            label: "Token moved",
+            value: symbol + " (" + token + ")",
+            address: token,
+            isToken: true,
+        },
+        to,
+    ];
+    const movedTo = (value) => ({ label: "Moved to", value });
+    const movedToAddress = (address) => ({
+        label: "Moved to",
+        value: address,
+        address,
+    });
+
+    test("1,000,000 USDT moved to another address, then a swap of 1 USDT", () => {
+        const result = decode(
+            execute(
+                permit2TransferFrom(USDT, OTHER, USDT_1000000),
+                v3SwapExactIn(MSG_SENDER, USDT_1, ONE_WETH, USDT, WETH),
+            ),
+        );
+        expect(detail(result, "Amount").value).toBe("1.0000 USDT");
+        expect(afterAmount(result)).toEqual(
+            moved("1000000.0000 USDT", USDT, "USDT", movedToAddress(OTHER)),
+        );
+        expect(paidTo(result)).toEqual([OTHER]);
+        expect(detail(result, "Min. paid out").value).toBe("1.0000 WETH");
+    });
+
+    test("1 WETH moved to the pair the next V2 swap spends", () => {
+        const result = decode(
+            execute(
+                permit2TransferFrom(WETH, PAIR, ONE_WETH),
+                v2Swap(0x08, MSG_SENDER, 0n, USDC_1990, [WETH, USDC], false),
+            ),
+        );
+        expect(detail(result, "Amount").value).toBe(
+            "Whatever an earlier step sent to the pair (V2 already paid)",
+        );
+        expect(afterAmount(result)).toEqual(
+            moved(
+                "1.0000 WETH",
+                WETH,
+                "WETH",
+                movedTo("The V2 pair the next swap spends"),
+            ),
+        );
+        expect(paidTo(result)).toEqual([]);
+        expect(detail(result, "Min. received").value).toBe("1990.0000 USDC");
+    });
+
+    // Its Paid to and Token moved into the router lines already say what a
+    // move into the router moves, so it gets no lines after Amount.
+    test("2,000 USDT moved into the router, then a swap of 1 USDT from the router's balance, shows the 2,000 USDT once", () => {
+        const result = decode(
+            execute(
+                permit2TransferFrom(USDT, ADDRESS_THIS, USDT_2000),
+                v3SwapExactIn(MSG_SENDER, USDT_1, ONE_WETH, USDT, WETH, false),
+            ),
+        );
+        expect(detail(result, "Amount").value).toBe("1.0000 USDT");
+        expect(afterAmount(result)).toEqual([]);
+        expect(paidTo(result)).toEqual([movedIntoRouter("2000.0000 USDT")]);
+        expect(
+            result.details.filter((d) => d.value.includes("2000.0000 USDT")),
+        ).toHaveLength(1);
+        expect(detail(result, "Min. paid out").value).toBe("1.0000 WETH");
+    });
+
+    test("a move to address(1) goes to the sender, and each move is shown in step order", () => {
+        const result = decode(
+            execute(
+                permit2TransferFrom(USDT, MSG_SENDER, USDT_2000),
+                permit2TransferFrom(USDC, OTHER, USDC_1990),
+                swapToWeth(MSG_SENDER),
+            ),
+        );
+        expect(afterAmount(result)).toEqual([
+            ...moved("2000.0000 USDT", USDT, "USDT", movedTo("The sender")),
+            ...moved("1990.0000 USDC", USDC, "USDC", movedToAddress(OTHER)),
+        ]);
+    });
+});
+
 // A payout of only part of what the router holds leaves the rest there.
 describe("a payout of part of the router's output", () => {
     test.each([
@@ -2787,3 +2915,26 @@ describe("the screens show each token moved into the router as an address", () =
         }
     });
 });
+
+// The issue's example: 1,000,000 USDT moved to another address, then a swap
+// of 1 USDT. Both screens show the amount moved and where it goes.
+describe("the screens show what a PERMIT2_TRANSFER_FROM moves", () => {
+    const millionToOther = execute(
+        permit2TransferFrom(USDT, OTHER, 1000000000000n),
+        v3SwapExactIn(MSG_SENDER, 1000000n, ONE_WETH, USDT, WETH),
+    );
+
+    test.each([
+        { screen: "approval", show: showApproval },
+        { screen: "transaction detail", show: showDetail },
+    ])("the $screen screen", async ({ show }) => {
+        const html = await show(millionToOther);
+        expect(html).toContain("1000000.0000 USDT");
+        // Each line is drawn in a div of its own; the Paid to line names
+        // OTHER too, so the Moved to line's own div is checked.
+        const movedToLine = html
+            .split('<div class="mb-2">')
+            .find((line) => line.includes(">Moved to<"));
+        expect(movedToLine).toContain('data-copy="' + OTHER + '"');
+    });
+});