fix: an allowance to another spender leaves no Amount figure for its token and no Min. received (closes #658)
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Code that a step runs, such as a V4 pool's hook, can call a spender other
than the router, which can then take up to its allowance from the user's
wallet before the transaction ends. The Amount figure and Min. received took
no account of it.

In decode(), an allowance of Token In to a spender other than the router
now leaves no Amount line, as an unread permit already did, so the swap
steps' own takes get lines of their own. Any allowance to another spender,
or a permit or batch the decoder cannot read, makes the minimum read
Min. paid out. Permits to the router read as before.

Model: opus-5-5
This commit was merged in pull request #666.
This commit is contained in:
2026-10-21 06:24:51 +02:00
parent e2965469ba
commit 4be625dc06
4 changed files with 234 additions and 91 deletions
+27 -18
View File
@@ -1173,8 +1173,8 @@ fetched, without that cross-address check, and shows the row's figure.
**Decoded amount lines on the transaction approval screen:** the `Amount` line
of a decoded ERC-20 call, and the `Amount` and `Min. received` lines of a
decoded swap (see TxApproval below; `Min. received` reads `Min. paid out` unless
only the user is paid, see Transaction Decoding), do not always read as a
number. They can read:
only the user is paid and no allowance goes to a spender other than the router,
see Transaction Decoding), do not always read as a number. They can read:
- A formatted quantity, e.g. `17.1900 USDT`, when the token's scale is known:
truncated to four decimals, with the floor and the zero cases described above.
@@ -3197,8 +3197,9 @@ Currently supported:
`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) and no `Paid to` line is shown. `Paid to` lines after
`Token Out` name each other address paid; one reads
TransactionDetail), no `Paid to` line is shown, and no permit or batch grants
an allowance to a spender other than the router (see below). `Paid to` lines
after `Token Out` name each other address paid; one reads
`The bridge, which pays the deposit's recipient on another network` for a
bridge deposit; one reads, for example,
`The router, 2000.0000 USDT from the sender (later steps may not spend all of it)`
@@ -3252,7 +3253,8 @@ Currently supported:
(listed at the end of this section), a step whose input it cannot read, in
whole or in part, and a step it fails on. Every other `PERMIT2_PERMIT`, before
the step that sets the input side or after it, leaves `Token In` and the
`Amount` line as they read with no permit: a permit of 5,000 DAI to another
`Amount` line as they read with no permit, unless it lets a spender other than
the router take `Token In` (see below): a permit of 5,000 DAI to another
address and then a V3 exact-in of 600 USDT read `Swap USDT → USDC` with
`Amount 600.0000 USDT`, and so do that exact-in and then a permit of 5,000 DAI
to the router. When a permit's amount stands and the step that sets the input
@@ -3319,19 +3321,26 @@ Currently supported:
`PERMIT2_PERMIT` or `PERMIT2_PERMIT_BATCH` whose input the decoder cannot
read, such as one whose token or spender word has a nonzero top byte, may let
any spender take any amount of any token: it gives one `Permit2 allowance`
line alone, reading `Unknown (could not be decoded)`, and leaves no `Amount`
line, whose figure might be too low. These lines change neither the `Paid to`
lines nor the minimum's label: a permit or batch pays nobody. A step goes
unread when its recipient does not decode as an address, when it is a V3 swap
step whose path is shorter than one token address or has bytes after its last
hop, or when it is a command the decoder does not read: every command other
than `PERMIT2_PERMIT`, `PERMIT2_PERMIT_BATCH`, `PERMIT2_TRANSFER_FROM`,
`V2_SWAP_EXACT_IN`, `V2_SWAP_EXACT_OUT`, `V3_SWAP_EXACT_IN`,
`V3_SWAP_EXACT_OUT`, `V4_SWAP`, `SWEEP`, `TRANSFER`, `PAY_PORTION`,
`PAY_PORTION_FULL_PRECISION`, `ACROSS_V4_DEPOSIT_V3`, `WRAP_ETH`,
`UNWRAP_WETH` and `BALANCE_CHECK_ERC20` (`PERMIT2_TRANSFER_FROM_BATCH`,
`EXECUTE_SUB_PLAN` and the NFT commands among them), or a type its release
names no command for.
line alone, reading `Unknown (could not be decoded)`. These lines change no
`Paid to` line: a permit or batch pays nobody. But code that a step runs, such
as a V4 pool's hook or a token's own code, can call a spender other than the
router, which can then take up to its allowance from the user's wallet before
the transaction ends. So an allowance to any spender but the router, or a
permit or batch the decoder cannot read, makes the minimum read
`Min. paid out`, and when its token is `Token In`, or the decoder does not
know its token or `Token In`, it leaves no `Amount` line, whose figure might
be too low: a permit of 5,000 USDT to another address and then a V3 exact-in
of 600 USDT read with no `Amount` line, and the 600 USDT gets lines of its
own. A step goes unread when its recipient does not decode as an address, when
it is a V3 swap step whose path is shorter than one token address or has bytes
after its last hop, or when it is a command the decoder does not read: every
command other than `PERMIT2_PERMIT`, `PERMIT2_PERMIT_BATCH`,
`PERMIT2_TRANSFER_FROM`, `V2_SWAP_EXACT_IN`, `V2_SWAP_EXACT_OUT`,
`V3_SWAP_EXACT_IN`, `V3_SWAP_EXACT_OUT`, `V4_SWAP`, `SWEEP`, `TRANSFER`,
`PAY_PORTION`, `PAY_PORTION_FULL_PRECISION`, `ACROSS_V4_DEPOSIT_V3`,
`WRAP_ETH`, `UNWRAP_WETH` and `BALANCE_CHECK_ERC20`
(`PERMIT2_TRANSFER_FROM_BATCH`, `EXECUTE_SUB_PLAN` and the NFT commands among
them), or a type its release names no command for.
### Non-Goals Forever
+31 -11
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@@ -1355,8 +1355,9 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
};
// A PERMIT2_PERMIT or PERMIT2_PERMIT_BATCH at `step` whose input this
// decoder cannot read may let any spender take any amount of any
// token: one line says so, and there is no Amount line, whose figure
// may then be too low.
// token: one line says so, there is no Amount line, whose figure may
// then be too low, and the minimum reads Min. paid out (see
// toAnotherSpender).
const permitUnread = (step) => {
permits.push({ token: null, amount: null, spender: null, step });
stepsUnread.push(step);
@@ -2029,8 +2030,9 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
// Every other PERMIT2_PERMIT leaves Token In and the Amount line as
// they read with no permit, and gets lines of its own below. A step
// that may take from the sender what this decoder did not read leaves
// no figure, permit or not (see spentUnread()), and so does a permit
// or batch whose input it cannot read (see permitUnread()). An
// no figure, permit or not (see spentUnread()), and so do a permit
// or batch whose input it cannot read (see permitUnread()) and an
// allowance of Token In to another spender (see toAnotherSpender). An
// EXECUTE_SUB_PLAN step leaves both sides unknown (below).
const stepCommands = Array.from(
commandsBytes,
@@ -2216,16 +2218,30 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
return amountText(amount, info);
};
// Each allowance to a spender other than the router. Code that a step
// runs, such as a V4 pool's hook or a token's own code, can call that
// spender, which can then take up to the allowance from the sender
// before the transaction ends. A permit or batch this decoder could
// not read may be to any spender, of any token.
const toAnotherSpender = permits.filter(
(p) => !sameAddress(p.spender, toAddress),
);
// A null token in `spentFromSender`, a step this decoder did not read
// or a token it does not know, and one in `permits`, a permit or
// batch it could not read, leave no Amount figure, which may then be
// or a token it does not know, and an allowance to another spender
// that may be of Token In, leave no Amount figure, which may then be
// too low. With no Amount line, each take the total adds up gets
// lines of its own, first, so that every amount this decoder read is
// shown.
if (
present(inputAmount) &&
spentFromSender.every((s) => present(s.token)) &&
permits.every((p) => present(p.token))
toAnotherSpender.every(
(p) =>
present(p.token) &&
present(inputToken) &&
!sameAddress(p.token, inputToken),
)
) {
const amount = spentText(inputAmount, inInfo);
details.push({
@@ -2346,9 +2362,10 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
// step pays the bridge, when one moves the sender's tokens into the
// router, when a token stays in the router, and when a payout could
// not be read. The output is received by the sender only when some
// step pays the sender and there is no such line. When no step names
// anyone paid, one line says so. `paidTo` holds these lines and the
// token line after each line about a token in the router.
// step pays the sender, there is no such line, and no allowance goes
// to another spender (see toAnotherSpender). When no step names anyone
// paid, one line says so. `paidTo` holds these lines and the token
// line after each line about a token in the router.
const outputHeld =
present(outputToken) && heldByRouter.has(outputToken.toLowerCase());
const paidTo = paidElsewhere.map((address) => ({
@@ -2395,7 +2412,10 @@ function decode(data, toAddress, chainId, sources, fromAddress) {
if (payeeUnread) {
paidTo.push({ label: "Paid to", value: UNDECODED_CURRENCY });
}
const received = paidToSender && paidTo.length === 0;
const received =
paidToSender &&
paidTo.length === 0 &&
toAnotherSpender.length === 0;
if (!paidToSender && paidTo.length === 0) {
paidTo.push({ label: "Paid to", value: UNNAMED_CURRENCY });
}
+162 -59
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@@ -2108,12 +2108,6 @@ describe("uniswap decoder", () => {
const ONE_USDT_LINES = (spender) =>
permitLines("1.0000 USDT", USDT_ADDR, "USDT", spender);
test.each([
{
kind: "to another spender",
commands: [0x0a],
permits: [ONE_USDT_PERMIT(OTHER_ADDR)],
lines: ONE_USDT_LINES(OTHER_ADDR),
},
{
kind: "that the router lets fail",
commands: [0x8a],
@@ -2550,20 +2544,6 @@ describe("uniswap decoder", () => {
],
lines: USDT_600_LINES,
},
{
kind: "a PERMIT2_PERMIT of 5,000 USDT to another spender, then a V3 exact-in of 600 USDT,",
commands: [0x0a, 0x00],
inputs: [
encodePermit2(USDT_ADDR, USDT_5000, OTHER_ADDR),
V3_600,
],
lines: permitLines(
"5000.0000 USDT",
USDT_ADDR,
"USDT",
OTHER_ADDR,
),
},
{
kind: "a PERMIT2_PERMIT of 5,000 USDT to the router that the router may let fail, then a V3 exact-in of 600 USDT,",
commands: [0x8a, 0x00],
@@ -2677,45 +2657,41 @@ describe("uniswap decoder", () => {
const DAI_5000 = 5000000000000000000000n;
const MAX_UINT160 = 2n ** 160n - 1n;
// A batch names one spender for all its allowances.
test.each([
{ kind: "the router", spender: ROUTER_ADDR },
{ kind: "another spender", spender: OTHER_ADDR },
])(
"a PERMIT2_PERMIT_BATCH of 5,000 USDT and unlimited DAI to $kind, then a V3 exact-in of 600 USDT, shows each allowance",
({ spender }) => {
const result = decodeSteps(
[0x03, 0x00],
[
encodePermit2Batch(
[
[USDT_ADDR, USDT_5000],
[DAI_ADDR, MAX_UINT160],
],
spender,
),
V3_600,
],
);
expect(result.name).toBe("Swap USDT → USDC");
expect(linesBetweenTokens(result)).toEqual([
["Amount", "600.0000 USDT"],
...permitLines(
"5000.0000 USDT",
USDT_ADDR,
"USDT",
spender,
// A batch names one spender for all its allowances. One to
// another spender is under "an allowance to a spender other than
// the router" below.
test("a PERMIT2_PERMIT_BATCH of 5,000 USDT and unlimited DAI to the router, then a V3 exact-in of 600 USDT, shows each allowance", () => {
const result = decodeSteps(
[0x03, 0x00],
[
encodePermit2Batch(
[
[USDT_ADDR, USDT_5000],
[DAI_ADDR, MAX_UINT160],
],
ROUTER_ADDR,
),
...permitLines("Unlimited", DAI_ADDR, "DAI", spender),
]);
// A batch pays nobody, so the swap's minimum is what the
// sender receives.
expect(detail(result, "Paid to")).toBeUndefined();
expect(detail(result, "Min. received").value).toBe(
"590.0000 USDC",
);
},
);
V3_600,
],
);
expect(result.name).toBe("Swap USDT → USDC");
expect(linesBetweenTokens(result)).toEqual([
["Amount", "600.0000 USDT"],
...permitLines(
"5000.0000 USDT",
USDT_ADDR,
"USDT",
ROUTER_ADDR,
),
...permitLines("Unlimited", DAI_ADDR, "DAI", ROUTER_ADDR),
]);
// A batch pays nobody, so the swap's minimum is what the
// sender receives.
expect(detail(result, "Paid to")).toBeUndefined();
expect(detail(result, "Min. received").value).toBe(
"590.0000 USDC",
);
});
// A batch keeps a PERMIT2_PERMIT's amount from standing as the
// Amount figure, before the permit as after it.
@@ -2768,7 +2744,7 @@ describe("uniswap decoder", () => {
),
},
])(
"$kind that cannot be read, then a V3 exact-in of 600 USDT, says its allowances could not be decoded and shows no Amount figure",
"$kind that cannot be read, then a V3 exact-in of 600 USDT, says its allowances could not be decoded and shows no Amount figure and no Min. received",
({ command, input }) => {
const result = decodeSteps(
[command, 0x00],
@@ -2778,6 +2754,14 @@ describe("uniswap decoder", () => {
...USDT_600_GROUP,
["Permit2 allowance", UNDECODED],
]);
// Its spender may be any address, as with an allowance
// to a spender other than the router (below).
// https://git.eeqj.de/sneak/AutistMask/issues/658 — on
// next at e296546 this read Min. received.
expect(detail(result, "Min. received")).toBeUndefined();
expect(detail(result, "Min. paid out").value).toBe(
"590.0000 USDC",
);
},
);
@@ -2806,6 +2790,125 @@ describe("uniswap decoder", () => {
});
});
// https://git.eeqj.de/sneak/AutistMask/issues/658 — code that a step
// runs can call a spender other than the router, which can then take
// up to its allowance from the sender before the transaction ends.
// On next at e296546 the Amount figure and Min. received took no
// account of it. An allowance of Token In to another spender now
// leaves no Amount figure, the swap steps' own takes get lines of
// their own, and any allowance to another spender leaves no Min.
// received.
describe("an allowance to a spender other than the router", () => {
const USDT_5000 = 5000000000n;
const DAI_5000 = 5000000000000000000000n;
const MAX_UINT160 = 2n ** 160n - 1n;
const USDT_5000_LINES = permitLines(
"5000.0000 USDT",
USDT_ADDR,
"USDT",
OTHER_ADDR,
);
test.each([
{
kind: "a PERMIT2_PERMIT of 5,000 USDT to another spender, then a V3 exact-in of 600 USDT,",
commands: [0x0a, 0x00],
inputs: [
encodePermit2(USDT_ADDR, USDT_5000, OTHER_ADDR),
V3_600,
],
lines: [...USDT_600_GROUP, ...USDT_5000_LINES],
minimum: "590.0000 USDC",
},
{
kind: "a V3 exact-in of 600 USDT, then a PERMIT2_PERMIT of 5,000 USDT to another spender,",
commands: [0x00, 0x0a],
inputs: [
V3_600,
encodePermit2(USDT_ADDR, USDT_5000, OTHER_ADDR),
],
lines: [...USDT_600_GROUP, ...USDT_5000_LINES],
minimum: "590.0000 USDC",
},
{
kind: "a PERMIT2_PERMIT_BATCH of 5,000 USDT and unlimited DAI to another spender, then a V3 exact-in of 600 USDT,",
commands: [0x03, 0x00],
inputs: [
encodePermit2Batch(
[
[USDT_ADDR, USDT_5000],
[DAI_ADDR, MAX_UINT160],
],
OTHER_ADDR,
),
V3_600,
],
lines: [
...USDT_600_GROUP,
...USDT_5000_LINES,
...permitLines(
"Unlimited",
DAI_ADDR,
"DAI",
OTHER_ADDR,
),
],
minimum: "590.0000 USDC",
},
{
kind: "a PERMIT2_PERMIT of 1 USDT to another spender, then a V3 exact-in of 600 USDT and a V2 exact-in of 400 USDT, both paid by the user,",
commands: [0x0a, 0x00, 0x08],
inputs: [
ONE_USDT_PERMIT(OTHER_ADDR),
V3_600,
encodeV2SwapExactIn(USER_ADDR, USDT_400, 390000000n, [
USDT_ADDR,
USDC_ADDR,
]),
],
lines: [
...USDT_600_GROUP,
...USDT_400_GROUP,
...ONE_USDT_LINES(OTHER_ADDR),
],
// The last swap step's minimum.
minimum: "390.0000 USDC",
},
])(
"$kind shows each take's own lines and the allowances, and no Amount figure or Min. received",
({ commands, inputs, lines, minimum }) => {
const result = decodeSteps(commands, inputs);
expect(result.name).toBe("Swap USDT → USDC");
expect(linesBetweenTokens(result)).toEqual(lines);
expect(detail(result, "Paid to")).toBeUndefined();
expect(detail(result, "Min. received")).toBeUndefined();
expect(detail(result, "Min. paid out").value).toBe(minimum);
},
);
// An allowance of another token leaves the Amount figure for
// Token In.
test("a PERMIT2_PERMIT of 5,000 DAI to another spender, then a V3 exact-in of 600 USDT, shows the swap's 600 USDT and no Min. received", () => {
const result = decodeSteps(
[0x0a, 0x00],
[encodePermit2(DAI_ADDR, DAI_5000, OTHER_ADDR), V3_600],
);
expect(linesBetweenTokens(result)).toEqual([
["Amount", "600.0000 USDT"],
...permitLines(
"5000.0000 DAI",
DAI_ADDR,
"DAI",
OTHER_ADDR,
),
]);
expect(detail(result, "Min. received")).toBeUndefined();
expect(detail(result, "Min. paid out").value).toBe(
"590.0000 USDC",
);
});
});
// A V3_SWAP_EXACT_OUT whose path is shorter than one token cannot be
// read. It may pay any address and take from the sender, so it
// leaves no Amount figure.
+14 -3
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@@ -2802,26 +2802,37 @@ describe("the allow-revert flag", () => {
});
// Only the routers from UniversalRouterV2 on let a PERMIT2_PERMIT fail.
// The permit's spender is the router at ROUTER, which on every other
// router is an allowance to another spender, so the minimum reads
// Min. paid out there.
test.each([
{ router: "UniversalRouterV1", address: ROUTER_V1, mark: "" },
{
router: "UniversalRouterV1",
address: ROUTER_V1,
mark: "",
minimum: "Min. paid out",
},
{
router: "UniversalRouterV1_2_V2Support",
address: ROUTER_V1_2,
mark: "",
minimum: "Min. paid out",
},
{
router: "UniversalRouterV2",
address: ROUTER,
mark: " (allowed to fail)",
minimum: "Min. received",
},
{
router: "UniversalRouterV2_1_2",
address: ROUTER_V2_1_2,
mark: " (allowed to fail)",
minimum: "Min. paid out",
},
])(
"on $router, a PERMIT2_PERMIT with the flag is listed as 'Permit2 Permit$mark', and the swap's lines read as without the flag",
({ address, mark }) => {
({ address, mark, minimum }) => {
const steps = [
permit2Permit(USDT, USDT_2000),
swapToWeth(MSG_SENDER),
@@ -2853,7 +2864,7 @@ describe("the allow-revert flag", () => {
expect(
labels(withFlag).filter((l) => permitLines.includes(l)),
).toEqual(permitLines);
expect(detail(withFlag, "Min. received").value).toBe("1.0000 WETH");
expect(detail(withFlag, minimum).value).toBe("1.0000 WETH");
},
);