fix: a V4 swap action not in the deployed shape is shown as not decoded (closes #358)
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The four V4 swap actions are read only as the parameter structs deployed
on mainnet and Sepolia. ethers decoded the newer v4-periphery structs,
which add minHopPriceX36, as the deployed ones without an error, and the
newer multi-hop exact-in struct showed the offset of its hop-price array
as the swap amount. A decode now counts only when encoding it again gives
back the same bytes. A swap action that fails that marks its step "V4
Swap (could not be decoded)", and a side of the swap that its SETTLE or
TAKE did not name reads "Unknown (could not be decoded)" instead of
another step's token and figure. The README records both.

Model: opus-5-5
This commit is contained in:
2026-10-14 18:37:19 +00:00
parent f4551dcb67
commit f938950161
4 changed files with 360 additions and 31 deletions
+269 -3
View File
@@ -163,6 +163,122 @@ function encodeV4ExactInSingle(currency0, currency1, amountIn, amountOutMin) {
);
}
// 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.
const POOL_KEY = "tuple(address,address,uint24,int24,address)";
const PATH_KEY = "tuple(address,uint24,int24,address,bytes)";
const WETH_USDC_POOL = [WETH_ADDR, USDC_ADDR, 100, 1, ZERO_ADDR];
const ONE_WETH = 1000000000000000000n;
const V4_SWAP_ACTION_SHAPES = [
{
action: "SWAP_EXACT_IN_SINGLE",
id: 0x06,
deployed: coder.encode(
[`tuple(${POOL_KEY},bool,uint128,uint128,bytes)`],
[[WETH_USDC_POOL, true, ONE_WETH, 990000n, "0x"]],
),
newer: coder.encode(
[`tuple(${POOL_KEY},bool,uint128,uint128,uint256,bytes)`],
[[WETH_USDC_POOL, true, ONE_WETH, 990000n, 0n, "0x"]],
),
},
{
action: "SWAP_EXACT_IN",
id: 0x07,
deployed: coder.encode(
[`tuple(address,${PATH_KEY}[],uint128,uint128)`],
[
[
WETH_ADDR,
[[USDC_ADDR, 100, 1, ZERO_ADDR, "0x"]],
ONE_WETH,
990000n,
],
],
),
newer: coder.encode(
[`tuple(address,${PATH_KEY}[],uint256[],uint128,uint128)`],
[
[
WETH_ADDR,
[[USDC_ADDR, 100, 1, ZERO_ADDR, "0x"]],
[],
ONE_WETH,
990000n,
],
],
),
},
{
action: "SWAP_EXACT_OUT_SINGLE",
id: 0x08,
deployed: coder.encode(
[`tuple(${POOL_KEY},bool,uint128,uint128,bytes)`],
[[WETH_USDC_POOL, true, 990000n, ONE_WETH, "0x"]],
),
newer: coder.encode(
[`tuple(${POOL_KEY},bool,uint128,uint128,uint256,bytes)`],
[[WETH_USDC_POOL, true, 990000n, ONE_WETH, 0n, "0x"]],
),
},
{
action: "SWAP_EXACT_OUT",
id: 0x09,
deployed: coder.encode(
[`tuple(address,${PATH_KEY}[],uint128,uint128)`],
[
[
USDC_ADDR,
[[WETH_ADDR, 100, 1, ZERO_ADDR, "0x"]],
990000n,
ONE_WETH,
],
],
),
newer: coder.encode(
[`tuple(address,${PATH_KEY}[],uint256[],uint128,uint128)`],
[
[
USDC_ADDR,
[[WETH_ADDR, 100, 1, ZERO_ADDR, "0x"]],
[],
990000n,
ONE_WETH,
],
],
),
},
];
// Helper: execute() with one V4_SWAP step holding the swap action, then
// SETTLE of WETH and TAKE of USDC.
function v4SwapCalldata(actionId, swapParams) {
return buildExecute(
"0x10",
[
encodeV4Swap(new Uint8Array([actionId, V4_SETTLE_ID, V4_TAKE_ID]), [
swapParams,
encodeV4Settle(WETH_ADDR),
encodeV4Take(USDC_ADDR),
]),
],
9999999999n,
);
}
// 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.
const V4_SETTLE_ALL_ID = 0x0c;
const V4_TAKE_ALL_ID = 0x0f;
function encodeV4SettleAll(currency, maxAmount) {
return coder.encode(["address", "uint256"], [currency, maxAmount]);
}
function encodeV4TakeAll(currency, minAmount) {
return coder.encode(["address", "uint256"], [currency, minAmount]);
}
function detail(result, label) {
return result.details.find((d) => d.label === label);
}
@@ -203,9 +319,157 @@ describe("uniswap decoder", () => {
result.details.find((d) => d.label === "Min. received").value,
).toBe("0.0002 ETH");
// Real mainnet calldata is in the deployed shape, so its V4 step is
// not said to be undecoded.
const steps = result.details.find((d) => d.label === "Steps");
expect(steps.value).toContain("Permit2 Permit");
expect(steps.value).toContain("V4 Swap");
expect(steps.value).toBe("Permit2 Permit → V4 Swap");
});
test.each(V4_SWAP_ACTION_SHAPES)(
"a V4 $action in the deployed shape is read",
({ id, deployed }) => {
const result = uniswap.decode(
v4SwapCalldata(id, deployed),
ROUTER_ADDR,
);
expect(detail(result, "Steps").value).toBe("V4 Swap");
},
);
// https://git.eeqj.de/sneak/AutistMask/issues/358 — before it, all four
// newer structs decoded as the deployed ones without an error, and the
// newer SWAP_EXACT_IN showed the offset of its hop-price array as Amount
// ("0.0000000000000004 WETH") and its amountIn as Min. received.
test.each(V4_SWAP_ACTION_SHAPES)(
"a V4 $action in the newer periphery shape is shown as not decoded",
({ id, newer }) => {
const result = uniswap.decode(
v4SwapCalldata(id, newer),
ROUTER_ADDR,
);
expect(detail(result, "Amount")).toBeUndefined();
expect(detail(result, "Min. received")).toBeUndefined();
expect(detail(result, "Steps").value).toBe(
"V4 Swap (could not be decoded)",
);
// SETTLE and TAKE keep their own shape and still name both sides.
expect(detail(result, "Token In").address).toBe(WETH_ADDR);
expect(detail(result, "Token Out").address).toBe(USDC_ADDR);
},
);
// 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 $action in the newer shape, then SETTLE_ALL and TAKE_ALL, says both tokens could not be decoded",
({ id, newer }) => {
const data = buildExecute(
"0x10",
[
encodeV4Swap(
new Uint8Array([id, V4_SETTLE_ALL_ID, V4_TAKE_ALL_ID]),
[
newer,
encodeV4SettleAll(WETH_ADDR, ONE_WETH),
encodeV4TakeAll(USDC_ADDR, 990000n),
],
),
],
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)",
);
expect(detail(result, "Token Out").value).toBe(
"Unknown (could not be decoded)",
);
},
);
// The user receives the V4 step's USDC, which only its unread swap
// 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",
({ id, newer }) => {
const data = buildExecute(
solidityPacked(["uint8", "uint8"], [0x00, 0x10]),
[
encodeV3SwapExactIn(USER_ADDR, 2000000n, ONE_WETH, [
USDT_ADDR,
WETH_ADDR,
]),
encodeV4Swap(new Uint8Array([id, V4_TAKE_ALL_ID]), [
newer,
encodeV4TakeAll(USDC_ADDR, 990000n),
]),
],
9999999999n,
);
const result = uniswap.decode(data, ROUTER_ADDR);
expect(result.name).toBe("Uniswap Swap");
expect(detail(result, "Amount").value).toBe("2.0000 USDT");
expect(detail(result, "Token Out").value).toBe(
"Unknown (could not be decoded)",
);
expect(detail(result, "Min. received")).toBeUndefined();
},
);
// 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",
({ id, newer }) => {
const data = buildExecute(
solidityPacked(["uint8", "uint8"], [0x10, 0x00]),
[
encodeV4Swap(new Uint8Array([id, V4_SETTLE_ALL_ID]), [
newer,
encodeV4SettleAll(WETH_ADDR, ONE_WETH),
]),
encodeV3SwapExactIn(
USER_ADDR,
990000n,
980000000000000000n,
[USDC_ADDR, DAI_ADDR],
),
],
9999999999n,
);
const result = uniswap.decode(data, ROUTER_ADDR);
expect(result.name).toBe("Uniswap Swap");
expect(detail(result, "Token In").value).toBe(
"Unknown (could not be decoded)",
);
expect(detail(result, "Amount")).toBeUndefined();
expect(detail(result, "Min. received").value).toBe("0.9800 DAI");
},
);
// UNWRAP_WETH makes Token Out ETH when no step set the output side. An
// unread swap action's step did set it, to undetermined.
test("an UNWRAP_WETH after an unread V4 swap action does not make Token Out ETH", () => {
const { id, newer } = V4_SWAP_ACTION_SHAPES[0];
const data = buildExecute(
solidityPacked(["uint8", "uint8"], [0x10, 0x0c]),
[
encodeV4Swap(new Uint8Array([id, V4_TAKE_ALL_ID]), [
newer,
encodeV4TakeAll(USDC_ADDR, 990000n),
]),
encodeWrapEth(USER_ADDR, 0n), // UNWRAP_WETH, same encoding
],
9999999999n,
);
const result = uniswap.decode(data, ROUTER_ADDR);
expect(detail(result, "Token Out").value).toBe(
"Unknown (could not be decoded)",
);
});
test("decodes V2_SWAP_EXACT_IN with known tokens", () => {
@@ -548,9 +812,11 @@ describe("uniswap decoder", () => {
const result = uniswap.decode(data, ROUTER_ADDR);
expect(result).not.toBeNull();
// The V4 swap action's parameters are empty, so that step is said to
// be undecoded.
const steps = result.details.find((d) => d.label === "Steps");
expect(steps.value).toBe(
"Permit2 Permit \u2192 V4 Swap \u2192 Unwrap WETH",
"Permit2 Permit \u2192 V4 Swap (could not be decoded) \u2192 Unwrap WETH",
);
});
+5 -1
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@@ -97,7 +97,11 @@ describe("an execute() whose input currency never decoded", () => {
]);
test("says the input token is unknown instead of naming ETH", () => {
expect(detail(data(), "Token In").value).toBe(REFUSAL);
// The swap action that would name it could not be read, so the line
// says that rather than REFUSAL's "not named in the calldata".
expect(detail(data(), "Token In").value).toBe(
"Unknown (could not be decoded)",
);
});
test("keeps a Token In line, so the screen never omits what is paid", () => {