fix: the swap decoder reads who the router's transfer commands pay (closes #599)

TRANSFER, PAY_PORTION, PAY_PORTION_FULL_PRECISION (0x07, on the routers with
the 0x7f mask), PERMIT2_TRANSFER_FROM and V4 TAKE_PORTION were payouts the
decoder did not read, so a swap using one read Min. paid out with an unknown
payee. Each recipient is now read under the rule swap steps follow: the
sender, the router, a hop into the next V2 pair, or another address, which is
named. Paying all the router holds of a token pays it out as SWEEP does; a
part leaves the rest in the router. UniversalRouterV1 pays a
PERMIT2_TRANSFER_FROM to address(1) or address(2) as written. 0x07 and
ACROSS_V4_DEPOSIT_V3 (0x40) are named in Steps; the deposit stays unread.

Model: opus-5-5

README.md

@@ -2955,45 +2955,58 @@ Currently supported:
   address uses: `0x1f` for `UniversalRouterV1`, `0x3f` for
   `UniversalRouterV1_2_V2Support` and `UniversalRouterV2`, and `0x7f` for
   `UniversalRouterV2_1_1` and `UniversalRouterV2_1_2`. The allow-revert flag
-  (`0x80`) therefore does not change a step's name. The decoder does not read
+  (`0x80`) therefore does not change a step's name. Only the routers with the
-  the commands inside an `EXECUTE_SUB_PLAN` (`0x21`) step, and wherever that
+  `0x7f` mask have `PAY_PORTION_FULL_PRECISION` (`0x07`), listed as
-  step stands they may spend the user's tokens or pay the user. That step is
+  `Pay Portion (Full Precision)`, and `ACROSS_V4_DEPOSIT_V3` (`0x40`), listed as
-  listed as `Execute Sub-Plan (its steps are not shown)`, and whatever the other
+  `Across Bridge Deposit`; the other routers revert on `0x07`, and it is listed
-  steps state, the summary names no swap direction, `Token In` and `Token Out`
+  there as `Command 0x07`. The decoder does not read the commands inside an
-  read `Unknown (could not be decoded)`, and there is no `Amount` or
+  `EXECUTE_SUB_PLAN` (`0x21`) step, and wherever that step stands they may spend
-  `Min. received` line. Each swap step, `SWEEP`, `WRAP_ETH`, `UNWRAP_WETH` and
+  the user's tokens or pay the user. That step is listed as
-  V4 `TAKE` names the address it pays, and `TAKE_ALL` pays the transaction's
+  `Execute Sub-Plan (its steps are not shown)`, and whatever the other steps
-  sender. The router reads `address(1)` as the transaction's sender, and
+  state, the summary names no swap direction, `Token In` and `Token Out` read
-  `address(2)` as the router itself, which holds what it is paid until a later
+  `Unknown (could not be decoded)`, and there is no `Amount` or `Min. received`
-  step pays it out; a payment to the router, as `address(2)` or by its own
+  line. Each swap step, `SWEEP`, `WRAP_ETH`, `UNWRAP_WETH`, `TRANSFER`,
-  address, is not counted as paid out. When a swap step or `TAKE` pays the
+  `PAY_PORTION`, `PAY_PORTION_FULL_PRECISION`, `PERMIT2_TRANSFER_FROM` (which
-  router the swap's output token, the output stays in the router unless a later
+  moves the user's own tokens) and V4 `TAKE` and `TAKE_PORTION` names the
-  `SWEEP` of that token, or a later `UNWRAP_WETH` when it is WETH, pays it out.
+  address it pays, and `TAKE_ALL` pays the transaction's sender. The router
-  A swap step or `TAKE` paying a token to the V2 pair that the very next step
+  reads `address(1)` as the transaction's sender, and `address(2)` as the router
-  spends, as a V2 exact-in of that token whose `amountIn` is `ALREADY_PAID`
+  itself, which holds what it is paid until a later step pays it out; a payment
-  (zero) or `CONTRACT_BALANCE`, is a hop, not a payout: Uniswap's mixed routes
+  to the router, as `address(2)` or by its own address, is not counted as paid
-  pay the next V2 pair directly, and the router enforces that swap's own
+  out. `UniversalRouterV1` alone pays a `PERMIT2_TRANSFER_FROM` to `address(1)`
-  minimum. The decoder checks that the address paid is that pair, deriving it
+  or `address(2)` as those addresses, and the decoder names them. When a swap
-  from the V2 factory and pair init code hash the network's routers were
+  step, `TAKE` or `TAKE_PORTION` pays the router the swap's output token, the
-  deployed with and the first two tokens of that step's path; a payment to any
+  output stays in the router unless a later step pays all the router holds of it
-  other address is named. (Sepolia's `UniversalRouterV1_2_V2Support` was
+  to anyone but the router: a `SWEEP` of that token, an `UNWRAP_WETH` when it is
-  deployed with placeholders for both values, so no V2 swap step can succeed on
+  WETH, or a `TRANSFER` of `CONTRACT_BALANCE`, a `PAY_PORTION` of 10,000 bips or
-  that router.) Every other payment counts, in whichever step and of whatever
+  a `PAY_PORTION_FULL_PRECISION` of 1e18 of that token. A step paying a token to
-  token. The minimum reads `Min. received` only when some step pays the
+  the V2 pair that the very next step spends, as a V2 exact-in of that token
-  transaction's sender (the From address on TxApproval, the sender the explorer
+  whose `amountIn` is `ALREADY_PAID` (zero) or `CONTRACT_BALANCE`, is a hop, not
-  reports on TransactionDetail), no step pays any other address, no step that
+  a payout: Uniswap's mixed routes pay the next V2 pair directly, and the router
-  may pay an address went unread, and the output does not stay in the router.
+  enforces that swap's own minimum. The decoder checks that the address paid is
-  Otherwise it reads `Min. paid out`, a `Paid to` line after `Token Out` names
+  that pair, deriving it from the V2 factory and pair init code hash the
-  each other address paid, one reads
+  network's routers were deployed with and the first two tokens of that step's
+  path; a payment to any other address is named. (Sepolia's
+  `UniversalRouterV1_2_V2Support` was deployed with placeholders for both
+  values, so no V2 swap step can succeed on that router.) Every other payment
+  counts, in whichever step and of whatever token, a share of the output
+  included: an interface fee paid to another address by `PAY_PORTION`,
+  `TRANSFER` or `TAKE_PORTION` is named, and the minimum reads `Min. paid out`,
+  because the swap's minimum includes the fee. The minimum reads `Min. received`
+  only when some step pays the transaction's sender (the From address on
+  TxApproval, the sender the explorer reports on TransactionDetail), no step
+  pays any other address, no step that may pay an address went unread, and the
+  output does not stay in the router. Otherwise it reads `Min. paid out`, a
+  `Paid to` line after `Token Out` names each other address paid, one reads
   `The router, where it stays (no later step pays it out)` when the output stays
   in the router, and one more reads `Unknown (could not be decoded)` when such a
   step went unread, or `Unknown (not named in the calldata)` when no step pays
   anyone. A step goes unread when its recipient does not decode as an address,
-  or when it is a command or V4 action the decoder does not read: every command
+  or when it is a command the decoder does not read: every command other than
-  other than `PERMIT2_PERMIT`, `V2_SWAP_EXACT_IN`, `V2_SWAP_EXACT_OUT`,
+  `PERMIT2_PERMIT`, `PERMIT2_TRANSFER_FROM`, `V2_SWAP_EXACT_IN`,
-  `V3_SWAP_EXACT_IN`, `V4_SWAP`, `SWEEP`, `WRAP_ETH`, `UNWRAP_WETH` and
+  `V2_SWAP_EXACT_OUT`, `V3_SWAP_EXACT_IN`, `V4_SWAP`, `SWEEP`, `TRANSFER`,
-  `BALANCE_CHECK_ERC20` (`V3_SWAP_EXACT_OUT`, `TRANSFER`, `PAY_PORTION` and
+  `PAY_PORTION`, `PAY_PORTION_FULL_PRECISION`, `WRAP_ETH`, `UNWRAP_WETH` and
-  `EXECUTE_SUB_PLAN` among them), and V4 `TAKE_PORTION`.
+  `BALANCE_CHECK_ERC20` (`V3_SWAP_EXACT_OUT`, `PERMIT2_TRANSFER_FROM_BATCH`,
+  `EXECUTE_SUB_PLAN` and `ACROSS_V4_DEPOSIT_V3` among them).
 
 ### Non-Goals Forever
 

src/shared/uniswap.js

@@ -123,7 +123,10 @@ function v2PairFor(chainId, tokenA, tokenB) {
 }
 
 // Universal Router command types, each read from its command byte with the
-// router's mask (see ROUTER_ADDRESSES)
+// router's mask (see ROUTER_ADDRESSES). Only the routers with the 0x7f mask
+// have 0x07 and 0x40: 0x40 is above the other masks, and the other routers
+// revert on 0x07, so decode() names it there as it names a command not
+// listed here.
 const COMMAND_NAMES = {
     0x00: "V3 Swap (Exact In)",
     0x01: "V3 Swap (Exact Out)",
@@ -132,6 +135,7 @@ const COMMAND_NAMES = {
     0x04: "Sweep",
     0x05: "Transfer",
     0x06: "Pay Portion",
+    0x07: "Pay Portion (Full Precision)",
     0x08: "V2 Swap (Exact In)",
     0x09: "V2 Swap (Exact Out)",
     0x0a: "Permit2 Permit",
@@ -145,6 +149,7 @@ const COMMAND_NAMES = {
     0x13: "V4 Initialize Pool",
     0x14: "V4 Position Mgr Call",
     0x21: "Execute Sub-Plan",
+    0x40: "Across Bridge Deposit",
 };
 
 // The swap's Amount and Min. received lines land on the same approval screen,
@@ -251,9 +256,11 @@ const WETH_ADDRESSES = [
 // Two recipient values the router reads as placeholders, not as addresses:
 // MSG_SENDER pays the caller of execute(), which is the transaction's sender,
 // and ADDRESS_THIS pays the router itself, which holds what it is paid until a
-// later step pays it out. The swap commands, SWEEP, WRAP_ETH and UNWRAP_WETH
+// later step pays it out. The swap commands, SWEEP, WRAP_ETH, UNWRAP_WETH,
-// map their recipient through the dispatcher's map(), and a V4 TAKE through
+// TRANSFER, PAY_PORTION, PAY_PORTION_FULL_PRECISION and, on every router but
-// V4Router's _mapRecipient(); TAKE_ALL always pays the caller.
+// UniversalRouterV1, PERMIT2_TRANSFER_FROM map their recipient through the
+// dispatcher's map(), and a V4 TAKE and TAKE_PORTION through V4Router's
+// _mapRecipient(); TAKE_ALL always pays the caller.
 // - constants: https://github.com/Uniswap/universal-router/blob/cda697da221e24ca143bc4f55023694a2a16796f/contracts/libraries/Constants.sol
 // - map(), UniversalRouterV1: https://github.com/Uniswap/universal-router/blob/cda697da221e24ca143bc4f55023694a2a16796f/contracts/libraries/Recipient.sol
 // - map(), UniversalRouterV2: https://github.com/Uniswap/universal-router/blob/3663f6db6e2fe121753cd2d899699c2dc75dca86/contracts/base/Dispatcher.sol
@@ -426,6 +433,46 @@ function decodeSweep(input) {
     }
 }
 
+// TRANSFER, PAY_PORTION, PAY_PORTION_FULL_PRECISION and PERMIT2_TRANSFER_FROM
+// read their parameters as each release's dispatcher reads them:
+// - UniversalRouterV1: https://github.com/Uniswap/universal-router/blob/cda697da221e24ca143bc4f55023694a2a16796f/contracts/base/Dispatcher.sol
+// - UniversalRouterV1_2_V2Support: https://github.com/Uniswap/universal-router/blob/41183d6eb154f0ab0e74a0e911a5ef9ea51fc4bd/contracts/base/Dispatcher.sol
+// - UniversalRouterV2: https://github.com/Uniswap/universal-router/blob/3663f6db6e2fe121753cd2d899699c2dc75dca86/contracts/base/Dispatcher.sol
+// - UniversalRouterV2_1_1: https://github.com/Uniswap/universal-router/blob/999d561c3ad58fb5cab91b602911f3c75591a9c7/contracts/base/Dispatcher.sol
+// - UniversalRouterV2_1_2: https://github.com/Uniswap/universal-router/blob/802fe4c18f47300e0f183e2a42e9146ec2ea9fc3/contracts/base/Dispatcher.sol
+
+// Decode TRANSFER (command 0x05) input bytes, and those of PAY_PORTION (0x06)
+// and PAY_PORTION_FULL_PRECISION (0x07), which share its layout. Each pays
+// `token` out of the router to the recipient. TRANSFER pays `amount`, or all
+// the router holds when `amount` is CONTRACT_BALANCE. PAY_PORTION pays
+// `amount` ten-thousandths of what the router holds, and
+// PAY_PORTION_FULL_PRECISION `amount` 1e18ths of it.
+// - UniversalRouterV1: https://github.com/Uniswap/universal-router/blob/cda697da221e24ca143bc4f55023694a2a16796f/contracts/modules/Payments.sol
+// - UniversalRouterV2_1_2: https://github.com/Uniswap/universal-router/blob/802fe4c18f47300e0f183e2a42e9146ec2ea9fc3/contracts/modules/Payments.sol
+// ABI: (address token, address recipient, uint256 amount)
+function decodeTransfer(input) {
+    try {
+        const d = coder.decode(["address", "address", "uint256"], input);
+        return { token: d[0], recipient: d[1], amount: d[2] };
+    } catch {
+        return null;
+    }
+}
+
+// Decode PERMIT2_TRANSFER_FROM (command 0x02) input bytes. Permit2 moves
+// `token` from the transaction's sender to the recipient. UniversalRouterV1
+// hands Permit2 the recipient as written, without map(), so on that router
+// address(1) and address(2) are paid as those addresses.
+// ABI: (address token, address recipient, uint160 amount)
+function decodePermit2TransferFrom(input) {
+    try {
+        const d = coder.decode(["address", "address", "uint160"], input);
+        return { token: d[0], recipient: d[1] };
+    } catch {
+        return null;
+    }
+}
+
 // Decode WRAP_ETH (command 0x0b) input bytes. The router pays the WETH to the
 // recipient.
 // ABI: (address recipient, uint256 amount)
@@ -615,9 +662,11 @@ function totalAmount(amounts) {
 // swap action sets only the sides SETTLE, SETTLE_ALL, TAKE and TAKE_ALL
 // name.
 //
-// `takes` is every TAKE and TAKE_ALL, as the currency it takes and its
+// `takes` is every TAKE, TAKE_ALL and TAKE_PORTION, as the currency it takes
-// recipient as written, MSG_SENDER for a TAKE_ALL. `recipientUnread` is set
+// and its recipient as written, MSG_SENDER for a TAKE_ALL. TAKE_PORTION takes
-// when the step has a payout this decoder did not read.
+// a share of the currency, so it does not name the output side as TAKE does.
+// `recipientUnread` is set when the step has a payout this decoder did not
+// read.
 function decodeV4Swap(input) {
     try {
         const d = coder.decode(["bytes", "bytes[]"], input);
@@ -663,6 +712,13 @@ function decodeV4Swap(input) {
                     const t = coder.decode(["address", "uint256"], params[i]);
                     takeToken = t[0];
                     takes.push({ currency: t[0], recipient: MSG_SENDER });
+                } else if (actionId === V4_TAKE_PORTION) {
+                    // TAKE_PORTION: (address currency, address recipient, uint256 bips)
+                    const t = coder.decode(
+                        ["address", "address", "uint256"],
+                        params[i],
+                    );
+                    takes.push({ currency: t[0], recipient: t[1] });
                 } else if (
                     actionId === V4_SWAP_EXACT_IN_SINGLE ||
                     actionId === V4_SWAP_EXACT_IN ||
@@ -674,17 +730,18 @@ function decodeV4Swap(input) {
                     } catch {
                         swapUndecoded = true;
                     }
-                } else if (actionId === V4_TAKE_PORTION) {
-                    // It pays a share of a currency to an address this decoder
-                    // does not read
-                    // (https://git.eeqj.de/sneak/AutistMask/issues/599).
-                    // V4Router reverts on any action not named here.
-                    recipientUnread = true;
                 }
+                // V4Router reverts on any action not named above, so none
+                // of them pays anyone.
             } catch {
-                // Skip sub-actions we can't decode. A TAKE or TAKE_ALL among
+                // Skip sub-actions we can't decode. A TAKE, TAKE_ALL or
-                // them is a payout this decoder did not read.
+                // TAKE_PORTION among them is a payout this decoder did not
-                if (actionId === V4_TAKE || actionId === V4_TAKE_ALL) {
+                // read.
+                if (
+                    actionId === V4_TAKE ||
+                    actionId === V4_TAKE_ALL ||
+                    actionId === V4_TAKE_PORTION
+                ) {
                     recipientUnread = true;
                 }
             }
@@ -824,31 +881,41 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
         const paidElsewhere = [];
         // Set when a step may pay an address this decoder did not read.
         let payeeUnread = false;
-        // The tokens, lowercased, that a swap step or a V4 TAKE paid to the
+        // The tokens, lowercased, that a swap step or a V4 TAKE or
-        // router and no later SWEEP of that token, or UNWRAP_WETH of WETH,
+        // TAKE_PORTION paid to the router and no later step paid out of it in
-        // paid out.
+        // full: a SWEEP of that token, an UNWRAP_WETH of WETH, or a TRANSFER,
+        // PAY_PORTION or PAY_PORTION_FULL_PRECISION of all the router holds of
+        // that token.
         const heldByRouter = new Set();
         const isRouter = (recipient) => {
             const r = recipient.toLowerCase();
             return r === ADDRESS_THIS || r === toAddress.toLowerCase();
         };
+        // A step pays `recipient`, an address other than the sender's or the
+        // router's, as written.
+        const addPaidElsewhere = (recipient) => {
+            const r = recipient.toLowerCase();
+            if (!paidElsewhere.some((a) => a.toLowerCase() === r)) {
+                paidElsewhere.push(recipient);
+            }
+        };
         // A step pays `recipient`. `output` is the token a swap step or a V4
-        // TAKE pays; other steps pass none.
+        // TAKE or TAKE_PORTION pays; other steps pass none.
         const addPayee = (recipient, output) => {
             const r = recipient.toLowerCase();
             if (isRouter(recipient)) {
                 if (present(output)) heldByRouter.add(output.toLowerCase());
             } else if (r === MSG_SENDER || r === sender) {
                 paidToSender = true;
-            } else if (!paidElsewhere.some((a) => a.toLowerCase() === r)) {
+            } else {
-                paidElsewhere.push(recipient);
+                addPaidElsewhere(recipient);
             }
         };
-        // A swap step or V4 TAKE that pays `token` to `recipient` is a hop,
+        // A step that pays `token` to `recipient` is a hop, not a payout,
-        // not a payout, when the very next step is a V2 exact-in whose input
+        // when the very next step is a V2 exact-in whose input is already
-        // is already paid, whose path starts at `token`, and whose pair (see
+        // paid, whose path starts at `token`, and whose pair (see v2PairFor())
-        // v2PairFor()) is `recipient`: Uniswap's mixed routes pay the next V2
+        // is `recipient`: Uniswap's mixed routes pay the next V2 pair
-        // pair directly, and the router enforces that next swap's own minimum.
+        // directly, and the router enforces that next swap's own minimum.
         // Its input is already paid when its amountIn is ALREADY_PAID, or
         // CONTRACT_BALANCE, which Uniswap's routes send and with which the
         // router adds only what it holds.
@@ -870,9 +937,14 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
 
         for (let i = 0; i < commandsBytes.length; i++) {
             const cmdId = commandsBytes[i] & commandTypeMask;
+            // Only the routers with the 0x7f mask have command 0x07 (see
+            // COMMAND_NAMES).
+            const name =
+                cmdId === 0x07 && commandTypeMask !== 0x7f
+                    ? null
+                    : COMMAND_NAMES[cmdId];
             commandNames.push(
-                COMMAND_NAMES[cmdId] ||
+                name || "Command 0x" + cmdId.toString(16).padStart(2, "0"),
-                    "Command 0x" + cmdId.toString(16).padStart(2, "0"),
             );
 
             try {
@@ -890,6 +962,23 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                     // input side an earlier hop established without breaking
                     // the invariant.
                     if (p) setInput(p.token, p.amount);
+                } else if (cmdId === 0x02) {
+                    const p = decodePermit2TransferFrom(inputs[i]);
+                    if (!p) {
+                        payeeUnread = true;
+                    } else if (
+                        commandTypeMask === 0x1f &&
+                        [MSG_SENDER, ADDRESS_THIS].includes(
+                            p.recipient.toLowerCase(),
+                        )
+                    ) {
+                        // UniversalRouterV1, the router with the 0x1f mask,
+                        // pays address(1) and address(2) as written (see
+                        // decodePermit2TransferFrom()).
+                        addPaidElsewhere(p.recipient);
+                    } else if (!isHop(i, p.token, p.recipient)) {
+                        addPayee(p.recipient);
+                    }
                 } else if (cmdId === 0x0e) {
                     const b = decodeBalanceCheck(inputs[i]);
                     // The router passes this check whenever the owner holds at
@@ -948,6 +1037,31 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                     } else {
                         payeeUnread = true;
                     }
+                } else if (
+                    cmdId === 0x05 ||
+                    cmdId === 0x06 ||
+                    (cmdId === 0x07 && commandTypeMask === 0x7f)
+                ) {
+                    const t = decodeTransfer(inputs[i]);
+                    if (t) {
+                        if (!isHop(i, t.token, t.recipient)) {
+                            addPayee(t.recipient);
+                        }
+                        // The amount with which TRANSFER, PAY_PORTION or
+                        // PAY_PORTION_FULL_PRECISION pays all the router
+                        // holds of the token, as SWEEP does.
+                        const all =
+                            cmdId === 0x05
+                                ? CONTRACT_BALANCE
+                                : cmdId === 0x06
+                                  ? 10000n
+                                  : 10n ** 18n;
+                        if (t.amount === all && !isRouter(t.recipient)) {
+                            heldByRouter.delete(t.token.toLowerCase());
+                        }
+                    } else {
+                        payeeUnread = true;
+                    }
                 } else if (cmdId === 0x0b) {
                     const w = decodeWrapEth(inputs[i]);
                     if (w) {
@@ -1016,9 +1130,9 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
                     }
                 } else {
                     // Any other command may pay an address this decoder does
-                    // not read: V3_SWAP_EXACT_OUT does, and so do TRANSFER,
+                    // not read: V3_SWAP_EXACT_OUT,
-                    // PAY_PORTION and the others
+                    // PERMIT2_TRANSFER_FROM_BATCH and ACROSS_V4_DEPOSIT_V3
-                    // https://git.eeqj.de/sneak/AutistMask/issues/599 lists.
+                    // among them.
                     payeeUnread = true;
                 }
             } catch {

tests/uniswap.test.js

@@ -954,7 +954,28 @@ describe("uniswap decoder", () => {
             router: "UniversalRouterV2_1_2",
             address: ROUTER_V2_1_2_ADDR,
             command: "0x40",
-            steps: "Command 0x40",
+            steps: "Across Bridge Deposit",
+        },
+        // Only the routers with the 0x7f mask have 0x07, as
+        // PAY_PORTION_FULL_PRECISION; the others revert on it
+        // (https://git.eeqj.de/sneak/AutistMask/issues/599).
+        {
+            router: "UniversalRouterV1",
+            address: ROUTER_V1_ADDR,
+            command: "0x07",
+            steps: "Command 0x07",
+        },
+        {
+            router: "UniversalRouterV2",
+            address: ROUTER_ADDR,
+            command: "0x07",
+            steps: "Command 0x07",
+        },
+        {
+            router: "UniversalRouterV2_1_2",
+            address: ROUTER_V2_1_2_ADDR,
+            command: "0x07",
+            steps: "Pay Portion (Full Precision)",
         },
     ])(
         "command $command sent to $router is listed as $steps",

tests/uniswapRecipient.test.js

@@ -1,12 +1,14 @@
 // The address a swap's output is paid to
-// (https://git.eeqj.de/sneak/AutistMask/issues/594).
+// (https://git.eeqj.de/sneak/AutistMask/issues/594 and
+// https://git.eeqj.de/sneak/AutistMask/issues/599).
 //
-// Every swap command, SWEEP, WRAP_ETH, UNWRAP_WETH and V4 TAKE names the
+// Every swap command, SWEEP, WRAP_ETH, UNWRAP_WETH, TRANSFER, PAY_PORTION,
-// address it pays, and TAKE_ALL pays the sender. The decoder read none of
+// PAY_PORTION_FULL_PRECISION, PERMIT2_TRANSFER_FROM and V4 TAKE and
-// them: a swap whose output went to another address still read "Min.
+// TAKE_PORTION names the address it pays, and TAKE_ALL pays the sender. The
-// received", as if the user received it. The router reads address(1) as the
+// decoder read none of them: a swap whose output went to another address
-// sender and address(2) as the router itself, which holds what it is paid
+// still read "Min. received", as if the user received it. The router reads
-// until a later step pays it out.
+// address(1) as the sender and address(2) as the router itself, which holds
+// what it is paid until a later step pays it out.
 //
 // The screens are driven against a minimal DOM stub in the shape
 // tests/uniswapRouterAddress.test.js uses.
@@ -41,6 +43,8 @@ const transactionDetail = require("../src/popup/views/transactionDetail");
 const ROUTER = "0x66a9893cc07d91d95644aedd05d03f95e1dba8af";
 // UniversalRouterV2_1_2 on Ethereum Mainnet, whose mask reads 0x07 and 0x40.
 const ROUTER_V2_1_2 = "0x23617e59A5925b2A4Bf75d73ff6711cD0b29De85";
+// UniversalRouterV1 on Ethereum Mainnet.
+const ROUTER_V1 = "0xEf1c6E67703c7BD7107eed8303Fbe6EC2554BF6B";
 const USER = "0x66133E8ea0f5D1d612D2502a968757D1048c214a";
 const OTHER = "0x7777777777777777777777777777777777777777";
 const MSG_SENDER = "0x0000000000000000000000000000000000000001";
@@ -53,6 +57,8 @@ const WETH = "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2";
 const ONE_WETH = 1000000000000000000n;
 const USDT_2000 = 2000000000n;
 const USDC_1990 = 1990000000n;
+// The router's whole-balance amount.
+const CONTRACT_BALANCE = 2n ** 255n;
 
 // The Paid to line's value when no address can be named.
 const UNDECODED = "Unknown (could not be decoded)";
@@ -89,7 +95,14 @@ function v2Swap(command, recipient, amount, limit, path, payerIsUser = true) {
     ];
 }
 
-function v3SwapExactIn(recipient, amountIn, amountOutMin, tokenIn, tokenOut) {
+function v3SwapExactIn(
+    recipient,
+    amountIn,
+    amountOutMin,
+    tokenIn,
+    tokenOut,
+    payerIsUser = true,
+) {
     return [
         0x00,
         coder.encode(
@@ -102,7 +115,7 @@ function v3SwapExactIn(recipient, amountIn, amountOutMin, tokenIn, tokenOut) {
                     ["address", "uint24", "address"],
                     [tokenIn, 3000, tokenOut],
                 ),
-                true,
+                payerIsUser,
             ],
         ),
     ];
@@ -115,6 +128,28 @@ function sweep(token, recipient) {
     ];
 }
 
+// TRANSFER (0x05), PAY_PORTION (0x06) and PAY_PORTION_FULL_PRECISION (0x07)
+// share one layout. `amount` is a quantity, bips, or 1e18ths respectively.
+function transfer(command, token, recipient, amount) {
+    return [
+        command,
+        coder.encode(
+            ["address", "address", "uint256"],
+            [token, recipient, amount],
+        ),
+    ];
+}
+
+function permit2TransferFrom(token, recipient, amount) {
+    return [
+        0x02,
+        coder.encode(
+            ["address", "address", "uint160"],
+            [token, recipient, amount],
+        ),
+    ];
+}
+
 function wrapEth(recipient, amount) {
     return [0x0b, coder.encode(["address", "uint256"], [recipient, amount])];
 }
@@ -168,6 +203,15 @@ function take(currency, recipient) {
 function takeAll(currency) {
     return [0x0f, coder.encode(["address", "uint256"], [currency, 0n])];
 }
+function takePortion(currency, recipient, bips) {
+    return [
+        0x10,
+        coder.encode(
+            ["address", "address", "uint256"],
+            [currency, recipient, bips],
+        ),
+    ];
+}
 
 // A V4_SWAP step of `actions`, each [action, params].
 function v4Swap(...actions) {
@@ -422,6 +466,216 @@ describe("an output left in the router is not received", () => {
     });
 });
 
+// https://git.eeqj.de/sneak/AutistMask/issues/599: TRANSFER, PAY_PORTION,
+// PAY_PORTION_FULL_PRECISION and V4 TAKE_PORTION pay a token to an address,
+// and PERMIT2_TRANSFER_FROM moves the user's own tokens to one.
+describe("each transfer command's recipient", () => {
+    // Each pays out all of a swap's output. Paid to another address, this is
+    // the first shape the issue reports.
+    test.each([
+        {
+            kind: "TRANSFER of CONTRACT_BALANCE",
+            data: (r) =>
+                execute(
+                    swapToWeth(ADDRESS_THIS),
+                    transfer(0x05, WETH, r, CONTRACT_BALANCE),
+                ),
+            min: "1.0000 WETH",
+        },
+        {
+            kind: "PAY_PORTION of 10,000 bips",
+            data: (r) =>
+                execute(
+                    swapToWeth(ADDRESS_THIS),
+                    transfer(0x06, WETH, r, 10000n),
+                ),
+            min: "1.0000 WETH",
+        },
+        {
+            kind: "PAY_PORTION_FULL_PRECISION of 1e18",
+            data: (r) =>
+                execute(
+                    swapToWeth(ADDRESS_THIS),
+                    transfer(0x07, WETH, r, 10n ** 18n),
+                ),
+            router: ROUTER_V2_1_2,
+            min: "1.0000 WETH",
+        },
+        {
+            kind: "V4 TAKE_PORTION of 10,000 bips",
+            data: (r) =>
+                execute(
+                    v4Swap(
+                        SWAP_USDT_FOR_USDC,
+                        SETTLE_USDT,
+                        takePortion(USDC, r, 10000n),
+                    ),
+                ),
+            min: "1990.0000 USDC",
+        },
+    ])(
+        "$kind: paid to the user it is received, to the router it stays there, to another address that address is named",
+        ({ data, router = ROUTER, min }) => {
+            const toUser = decode(data(MSG_SENDER), USER, router);
+            expect(labels(toUser)).toEqual(PAID_TO_USER);
+            expect(detail(toUser, "Min. received").value).toBe(min);
+            expect(decode(data(USER), USER, router).details).toEqual(
+                toUser.details,
+            );
+
+            const toRouter = decode(data(ADDRESS_THIS), USER, router);
+            expect(labels(toRouter)).toEqual(PAID_ELSEWHERE);
+            expect(paidTo(toRouter)).toEqual([STAYS_IN_ROUTER]);
+            expect(detail(toRouter, "Min. paid out").value).toBe(min);
+
+            const toOther = decode(data(OTHER), USER, router);
+            expect(labels(toOther)).toEqual(PAID_ELSEWHERE);
+            expect(paidTo(toOther)).toEqual([OTHER]);
+            expect(detail(toOther, "Min. paid out").value).toBe(min);
+        },
+    );
+
+    // The user's USDT, moved to `r`, then a swap of it paid to the user.
+    // The router spends what it is moved, so a move to the router pays no
+    // one. A move to another address is the issue's second shape.
+    const movedThenSwapped = (r) =>
+        execute(
+            permit2TransferFrom(USDT, r, USDT_2000),
+            v3SwapExactIn(MSG_SENDER, USDT_2000, ONE_WETH, USDT, WETH, false),
+        );
+
+    test("PERMIT2_TRANSFER_FROM: to the user or the router it pays no one else, to another address that address is named", () => {
+        for (const r of [MSG_SENDER, USER, ADDRESS_THIS, ROUTER]) {
+            const result = decode(movedThenSwapped(r));
+            expect(labels(result)).toEqual(PAID_TO_USER);
+            expect(detail(result, "Min. received").value).toBe("1.0000 WETH");
+        }
+
+        const toOther = decode(movedThenSwapped(OTHER));
+        expect(labels(toOther)).toEqual(PAID_ELSEWHERE);
+        expect(paidTo(toOther)).toEqual([OTHER]);
+        expect(detail(toOther, "Min. paid out").value).toBe("1.0000 WETH");
+
+        const alone = decode(
+            execute(permit2TransferFrom(USDT, OTHER, USDT_2000)),
+        );
+        expect(detail(alone, "Steps").value).toBe("Permit2 Transfer");
+        expect(paidTo(alone)).toEqual([OTHER]);
+    });
+
+    test("UniversalRouterV1 pays a PERMIT2_TRANSFER_FROM to address(1) or address(2) as written, and maps a TRANSFER's", () => {
+        for (const r of [MSG_SENDER, ADDRESS_THIS]) {
+            const result = decode(movedThenSwapped(r), USER, ROUTER_V1);
+            expect(paidTo(result)).toEqual([r]);
+            expect(detail(result, "Min. received")).toBeUndefined();
+        }
+
+        const transferred = decode(
+            execute(
+                swapToWeth(ADDRESS_THIS),
+                transfer(0x05, WETH, MSG_SENDER, CONTRACT_BALANCE),
+            ),
+            USER,
+            ROUTER_V1,
+        );
+        expect(labels(transferred)).toEqual(PAID_TO_USER);
+    });
+
+    test("a router without command 0x07 does not read it as PAY_PORTION_FULL_PRECISION", () => {
+        const result = decode(
+            execute(
+                swapToWeth(MSG_SENDER),
+                transfer(0x07, WETH, MSG_SENDER, 10n ** 18n),
+            ),
+        );
+        expect(detail(result, "Steps").value).toBe(
+            "V3 Swap (Exact In) → Command 0x07",
+        );
+        expect(paidTo(result)).toEqual([UNDECODED]);
+        expect(detail(result, "Min. received")).toBeUndefined();
+    });
+});
+
+// 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([
+        {
+            kind: "a TRANSFER of 1 base unit",
+            step: transfer(0x05, WETH, MSG_SENDER, 1n),
+        },
+        {
+            kind: "a PAY_PORTION of 5,000 bips",
+            step: transfer(0x06, WETH, MSG_SENDER, 5000n),
+        },
+        {
+            kind: "a PAY_PORTION_FULL_PRECISION of 1e18 less 1",
+            step: transfer(0x07, WETH, MSG_SENDER, 10n ** 18n - 1n),
+        },
+    ])("$kind to the user leaves the rest in the router", ({ step }) => {
+        const result = decode(
+            execute(swapToWeth(ADDRESS_THIS), step),
+            USER,
+            ROUTER_V2_1_2,
+        );
+        expect(labels(result)).toEqual(PAID_ELSEWHERE);
+        expect(paidTo(result)).toEqual([STAYS_IN_ROUTER]);
+        expect(detail(result, "Min. paid out").value).toBe("1.0000 WETH");
+    });
+
+    // An interface fee: a share of the output to another address, the rest
+    // to the user. The swap's minimum includes the fee, so it is not what the
+    // user receives.
+    test.each([
+        {
+            kind: "PAY_PORTION of 25 bips, then SWEEP",
+            data: execute(
+                swapToWeth(ADDRESS_THIS),
+                transfer(0x06, WETH, OTHER, 25n),
+                sweep(WETH, MSG_SENDER),
+            ),
+            min: "1.0000 WETH",
+        },
+        {
+            kind: "TRANSFER of a flat fee, then SWEEP",
+            data: execute(
+                swapToWeth(ADDRESS_THIS),
+                transfer(0x05, WETH, OTHER, ONE_WETH / 400n),
+                sweep(WETH, MSG_SENDER),
+            ),
+            min: "1.0000 WETH",
+        },
+        {
+            kind: "PAY_PORTION of 25 bips, then UNWRAP_WETH",
+            data: execute(
+                swapToWeth(ADDRESS_THIS),
+                transfer(0x06, WETH, OTHER, 25n),
+                unwrapWeth(MSG_SENDER),
+            ),
+            min: "1.0000 ETH",
+        },
+        {
+            kind: "V4 TAKE_PORTION of 25 bips, then TAKE_ALL",
+            data: execute(
+                v4Swap(
+                    SWAP_USDT_FOR_USDC,
+                    SETTLE_USDT,
+                    takePortion(USDC, OTHER, 25n),
+                    takeAll(USDC),
+                ),
+            ),
+            min: "1990.0000 USDC",
+        },
+    ])(
+        "a fee by $kind names the fee's recipient and calls nothing received",
+        ({ data, min }) => {
+            const result = decode(data);
+            expect(labels(result)).toEqual(PAID_ELSEWHERE);
+            expect(paidTo(result)).toEqual([OTHER]);
+            expect(detail(result, "Min. paid out").value).toBe(min);
+        },
+    );
+});
+
 // Uniswap's mixed routes pay a V2 pair directly when the next step swaps
 // through it. That V2 swap spends what the pair holds: its amountIn is
 // CONTRACT_BALANCE, paid from the router, or ALREADY_PAID. The pairs below
@@ -430,7 +684,6 @@ describe("an output left in the router is not received", () => {
 describe("a swap paid to the pair the next V2 swap spends", () => {
     // The WETH/USDC pair on Ethereum Mainnet, as its V2 factory reports it.
     const PAIR = "0xB4e16d0168e52d35CaCD2c6185b44281Ec28C9Dc";
-    const CONTRACT_BALANCE = 2n ** 255n;
     const AMOUNTS_IN = [
         { kind: "CONTRACT_BALANCE", amountIn: CONTRACT_BALANCE },
         { kind: "ALREADY_PAID", amountIn: 0n },
@@ -498,6 +751,36 @@ describe("a swap paid to the pair the next V2 swap spends", () => {
         },
     );
 
+    test.each([
+        {
+            kind: "ETH wrapped into the router, then a TRANSFER of all of it",
+            pay: (r) => [
+                wrapEth(ADDRESS_THIS, ONE_WETH),
+                transfer(0x05, WETH, r, CONTRACT_BALANCE),
+            ],
+        },
+        {
+            kind: "a PERMIT2_TRANSFER_FROM of the user's WETH",
+            pay: (r) => [permit2TransferFrom(WETH, r, ONE_WETH)],
+        },
+    ])(
+        "$kind, paid to the pair, is a hop; paid to another address, it is named",
+        ({ pay }) => {
+            const route = (r) =>
+                execute(...pay(r), pairSpends(0n, [WETH, USDC]));
+
+            const toPair = decode(route(PAIR));
+            expect(paidTo(toPair)).toEqual([]);
+            expect(detail(toPair, "Min. received").value).toBe(
+                "1990.0000 USDC",
+            );
+
+            const toOther = decode(route(OTHER));
+            expect(paidTo(toOther)).toEqual([OTHER]);
+            expect(detail(toOther, "Min. received")).toBeUndefined();
+        },
+    );
+
     describe("on Sepolia", () => {
         const SEPOLIA = "0xaa36a7";
         // UniversalRouterV2_1_2 on Sepolia.
@@ -661,13 +944,17 @@ describe("every step's payee counts, whichever step sets the output", () => {
 });
 
 describe("a payout that cannot be read is never said to be received", () => {
-    test("a V4 TAKE whose recipient word has its top byte set", () => {
+    test.each([
+        { kind: "TAKE", action: take(USDC, OTHER) },
+        { kind: "TAKE_PORTION", action: takePortion(USDC, OTHER, 25n) },
+    ])("a V4 $kind whose recipient word has its top byte set", ({ action }) => {
         const result = decode(
             execute(
                 v4Swap(
                     SWAP_USDT_FOR_USDC,
                     SETTLE_USDT,
-                    withDirtyWord(take(USDC, OTHER), 1),
+                    withDirtyWord(action, 1),
+                    takeAll(USDC),
                 ),
             ),
         );
@@ -689,11 +976,33 @@ describe("a payout that cannot be read is never said to be received", () => {
         { kind: "SWEEP", step: sweep(WETH, OTHER), word: 1 },
         { kind: "WRAP_ETH", step: wrapEth(OTHER, 1n) },
         { kind: "UNWRAP_WETH", step: unwrapWeth(OTHER) },
+        {
+            kind: "TRANSFER",
+            step: transfer(0x05, WETH, OTHER, 1n),
+            word: 1,
+        },
+        {
+            kind: "PAY_PORTION",
+            step: transfer(0x06, WETH, OTHER, 1n),
+            word: 1,
+        },
+        {
+            kind: "PAY_PORTION_FULL_PRECISION",
+            step: transfer(0x07, WETH, OTHER, 1n),
+            word: 1,
+        },
+        {
+            kind: "PERMIT2_TRANSFER_FROM",
+            step: permit2TransferFrom(WETH, OTHER, 1n),
+            word: 1,
+        },
     ])(
         "a $kind whose recipient word has its top byte set",
         ({ step, word = 0 }) => {
             const result = decode(
                 execute(swapToWeth(MSG_SENDER), withDirtyWord(step, word)),
+                USER,
+                ROUTER_V2_1_2,
             );
             expect(paidTo(result)).toEqual([UNDECODED]);
             expect(detail(result, "Min. received")).toBeUndefined();
@@ -719,17 +1028,8 @@ describe("a payout that cannot be read is never said to be received", () => {
         expect(detail(result, "Min. paid out").value).toBe("1.0000 WETH");
     });
 
-    // https://git.eeqj.de/sneak/AutistMask/issues/599 is to read these. Until
+    // Each is a payout this decoder does not read.
-    // then each is a payout this decoder does not read.
-    const transferShape = (command) => [
-        command,
-        coder.encode(["address", "address", "uint256"], [WETH, OTHER, 1n]),
-    ];
     test.each([
-        { kind: "PERMIT2_TRANSFER_FROM", step: transferShape(0x02) },
-        { kind: "TRANSFER", step: transferShape(0x05) },
-        { kind: "PAY_PORTION", step: transferShape(0x06) },
-        { kind: "PAY_PORTION_FULL_PRECISION", step: transferShape(0x07) },
         {
             kind: "PERMIT2_TRANSFER_FROM_BATCH",
             step: [
@@ -750,7 +1050,7 @@ describe("a payout that cannot be read is never said to be received", () => {
                 0x21,
                 coder.encode(
                     ["bytes", "bytes[]"],
-                    ["0x05", [transferShape(0x05)[1]]],
+                    ["0x05", [transfer(0x05, WETH, OTHER, 1n)[1]]],
                 ),
             ],
         },
@@ -758,16 +1058,6 @@ describe("a payout that cannot be read is never said to be received", () => {
             kind: "ACROSS_V4_DEPOSIT_V3",
             step: [0x40, coder.encode(["address"], [OTHER])],
         },
-        {
-            kind: "V4 TAKE_PORTION",
-            step: v4Swap([
-                0x10,
-                coder.encode(
-                    ["address", "address", "uint256"],
-                    [WETH, OTHER, 10000n],
-                ),
-            ]),
-        },
     ])("a swap paid to the user, then $kind", ({ step }) => {
         const result = decode(
             execute(swapToWeth(MSG_SENDER), step),