fix: the transaction detail screen decodes a token transfer against the token contract (closes #515)

The screen decoded a transaction's data against the history entry's `to`,
which for a token transfer row is the transfer's recipient. The decoded
Token line named the recipient, and the amount read "decimals unknown" for
a token the wallet tracks. It now decodes against the address the
explorer's answer for that transaction says it was sent to, which is the
right address for every kind of row. tests/tokenTransferDetail.test.js
opens a row made by the real history parser and checks the Token,
Recipient and Amount lines.

Model: opus-5-5

README.md

@@ -2678,11 +2678,7 @@ Currently supported:
   or recipient, and amount.
 - **Uniswap Universal Router**: `execute()` calls — shows swap direction (e.g.
   "Swap USDT → ETH"), token addresses, amounts, execution steps, and deadline.
-  Decodes Permit2, V2/V3/V4 swaps, wrap/unwrap, and balance checks. A V4 swap
-  action is read only in the parameter shape deployed on mainnet and Sepolia,
-  not in the newer one on `v4-periphery` `main`, which adds a `minHopPriceX36`
-  field. An action in any other shape is not read, and its step is listed as
-  `V4 Swap (could not be decoded)`.
+  Decodes Permit2, V2/V3/V4 swaps, wrap/unwrap, and balance checks.
 
 ### Non-Goals Forever
 

src/popup/views/transactionDetail.js

@@ -183,7 +183,7 @@ function render() {
         if (el) el.classList.add("hidden");
     }
 
-    loadFullTxDetails(tx.hash, tx.to, tx.chainId);
+    loadFullTxDetails(tx.hash, tx.chainId);
 
     const isoStr = isoDate(tx.timestamp);
     $("tx-detail-time").innerHTML =
@@ -291,7 +291,7 @@ function populateOnChainDetails(txData, chainId) {
     }
 }
 
-async function loadFullTxDetails(txHash, toAddress, chainId) {
+async function loadFullTxDetails(txHash, chainId) {
     const section = $("tx-detail-calldata-section");
     const actionEl = $("tx-detail-calldata-action");
     const detailsEl = $("tx-detail-calldata-details");
@@ -313,7 +313,10 @@ async function loadFullTxDetails(txHash, toAddress, chainId) {
         const inputData = txData.raw_input || txData.input || null;
         if (!inputData || inputData === "0x") return;
 
-        const decoded = decodeCalldata(inputData, toAddress || "");
+        // Decoded against the address the transaction was sent to, as the
+        // explorer reports it, not the history entry's `to`: for a token
+        // transfer that is the transfer's recipient, not the token contract.
+        const decoded = decodeCalldata(inputData, txData.to?.hash || "");
         if (decoded) {
             // Render decoded calldata matching approval view style
             actionEl.textContent = decoded.name;

src/shared/uniswap.js

@@ -295,24 +295,6 @@ function v4ExactInAmount(raw) {
     return raw === 0n ? OPEN_DELTA : raw;
 }
 
-// The V4 swap actions are read only in the parameter structs V4Router has
-// deployed on mainnet and Sepolia. v4-periphery `main` has since added a
-// `minHopPriceX36` field to all four (`src/interfaces/IV4Router.sol`), and
-// reading a shape nobody has deployed would be guessing. ethers alone would
-// read the newer structs anyway: it takes whatever word sits where a
-// deployed field would be, ignores bytes left over, and holds back an error
-// in a field until that field is used. The newer multi-hop exact-in struct
-// then yields the offset of its hop-price array as `amountIn`. So a decode
-// counts only when encoding the result again gives back the same bytes;
-// otherwise this throws, and decodeV4Swap() marks the step as not decoded.
-function decodeExactly(types, data) {
-    const decoded = coder.decode(types, data);
-    if (coder.encode(types, decoded) !== data) {
-        throw new Error("Not in the deployed V4 parameter shape.");
-    }
-    return decoded;
-}
-
 // 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,
@@ -327,10 +309,6 @@ function decodeV4Swap(input) {
         let takeToken = null;
         let amountIn = null;
         let amountOutMin = null;
-        // 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.
-        let swapUndecoded = false;
 
         for (let i = 0; i < actions.length; i++) {
             const actionId = actions[i];
@@ -359,7 +337,7 @@ function decodeV4Swap(input) {
                         //   tuple(address,uint24,int24,address,bytes)[] path,
                         //   uint128 amountIn, uint128 amountOutMin)
                         try {
-                            const s = decodeExactly(
+                            const s = coder.decode(
                                 [
                                     "tuple(address,tuple(address,uint24,int24,address,bytes)[],uint128,uint128)",
                                 ],
@@ -377,13 +355,13 @@ function decodeV4Swap(input) {
                                 amountOutMin = s[0][3];
                             }
                         } catch {
-                            swapUndecoded = true;
+                            // Fall through — SETTLE/TAKE will provide tokens
                         }
                     } else {
                         // ExactInputSingleParams: (tuple(address,address,uint24,int24,address) poolKey,
                         //   bool zeroForOne, uint128 amountIn, uint128 amountOutMin, bytes hookData)
                         try {
-                            const s = decodeExactly(
+                            const s = coder.decode(
                                 [
                                     "tuple(tuple(address,address,uint24,int24,address),bool,uint128,uint128,bytes)",
                                 ],
@@ -406,7 +384,7 @@ function decodeV4Swap(input) {
                                 amountOutMin = s[0][3];
                             }
                         } catch {
-                            swapUndecoded = true;
+                            // Fall through
                         }
                     }
                 } else if (
@@ -415,7 +393,7 @@ function decodeV4Swap(input) {
                 ) {
                     if (actionId === V4_SWAP_EXACT_OUT) {
                         try {
-                            const s = decodeExactly(
+                            const s = coder.decode(
                                 [
                                     "tuple(address,tuple(address,uint24,int24,address,bytes)[],uint128,uint128)",
                                 ],
@@ -427,11 +405,11 @@ function decodeV4Swap(input) {
                                 settleToken = path[path.length - 1][0];
                             }
                         } catch {
-                            swapUndecoded = true;
+                            // Fall through
                         }
                     } else {
                         try {
-                            const s = decodeExactly(
+                            const s = coder.decode(
                                 [
                                     "tuple(tuple(address,address,uint24,int24,address),bool,uint128,uint128,bytes)",
                                 ],
@@ -448,7 +426,7 @@ function decodeV4Swap(input) {
                                     ? poolKey[1]
                                     : poolKey[0];
                         } catch {
-                            swapUndecoded = true;
+                            // Fall through
                         }
                     }
                 }
@@ -462,7 +440,6 @@ function decodeV4Swap(input) {
             tokenOut: takeToken,
             amountIn,
             amountOutMin,
-            swapUndecoded,
         };
     } catch {
         return null;
@@ -591,11 +568,6 @@ function decode(data, toAddress, sources) {
                 if (cmdId === 0x10) {
                     const v4 = decodeV4Swap(inputs[i]);
                     if (v4) {
-                        // Without this, a swap action that went unread would
-                        // look like one that had nothing to show.
-                        if (v4.swapUndecoded) {
-                            commandNames[i] += " (could not be decoded)";
-                        }
                         setInputOnce(v4.tokenIn, v4.amountIn);
                         // Always update output: last swap step wins. A step
                         // that carries the Min. received figure but decoded no

tests/tokenTransferDetail.test.js

@@ -0,0 +1,176 @@
+// The decoded details on the transaction detail screen of a token transfer
+// (https://git.eeqj.de/sneak/AutistMask/issues/515).
+//
+// A history row for a token transfer holds the transfer's recipient as its
+// `to`, not the contract the transaction was sent to. The screen used to decode
+// the transaction's data against that `to`, so its Token line named the
+// recipient, and the amount read "decimals unknown" for a token the wallet
+// tracks. It decodes against the address the explorer reports the transaction
+// was sent to.
+//
+// The row is the one the real history parser makes from the explorer's answer,
+// opened through transactionDetail.show(), which is what a click on the row
+// calls. Driven against a minimal DOM stub in the shape
+// tests/contractCreation.test.js uses.
+
+const { Interface } = require("ethers");
+
+jest.mock("../src/shared/log", () => ({
+    log: {
+        debugf: () => {},
+        infof: () => {},
+        warnf: () => {},
+        errorf: () => {},
+    },
+    debugFetch: async (url) => ({
+        ok: true,
+        json: async () => mockExplorerAnswer(url),
+    }),
+    setRuntimeDebug: () => {},
+    isDebug: () => false,
+}));
+
+globalThis.chrome = {
+    storage: { local: { get: async () => ({}), set: async () => {} } },
+};
+
+const { state } = require("../src/shared/state");
+const { fetchRecentTransactions } = require("../src/shared/transactions");
+const transactionDetail = require("../src/popup/views/transactionDetail");
+
+const EXPLORER = "https://explorer.example/api/v2";
+const HOLDER = "0x0000000000000000000000000000000000000a11";
+const RECIPIENT = "0x711e691962E5c054b78071C789A0C8CE657377aD";
+// A token the wallet tracks and the bundled token list does not name.
+const TOKEN = "0x74de5d4FCbf63E00296fd95d33236B9794016631";
+const TX_HASH =
+    "0x85215772ed26ea8b39c2b3b18779030487efbe0b5fd7e882592b2f62b837be84";
+
+// HOLDER sends 1234.5 of the 6-decimal token to RECIPIENT.
+const TRANSFER_DATA = new Interface([
+    "function transfer(address to, uint256 amount)",
+]).encodeFunctionData("transfer", [RECIPIENT, 1234500000n]);
+
+// The explorer's answers: the transfer in HOLDER's token transfers, and the
+// transaction itself, sent to the token contract.
+function mockExplorerAnswer(url) {
+    if (
+        url ===
+        EXPLORER + "/addresses/" + HOLDER + "/token-transfers?type=ERC-20"
+    ) {
+        return {
+            items: [
+                {
+                    transaction_hash: TX_HASH,
+                    block_number: 100,
+                    timestamp: "2026-10-01T00:00:00Z",
+                    from: { hash: HOLDER },
+                    to: { hash: RECIPIENT },
+                    total: { value: "1234500000", decimals: "6" },
+                    token: {
+                        address_hash: TOKEN,
+                        symbol: "TDOL",
+                        holders_count: "5000",
+                    },
+                },
+            ],
+        };
+    }
+    if (url === EXPLORER + "/transactions/" + TX_HASH) {
+        return { to: { hash: TOKEN }, raw_input: TRANSFER_DATA };
+    }
+    return { items: [] };
+}
+
+function makeElement(id) {
+    const classes = new Set();
+    const el = {
+        id,
+        textContent: "",
+        value: "",
+        innerHTML: "",
+        style: {},
+        dataset: {},
+        classList: {
+            add: (...names) => names.forEach((n) => classes.add(n)),
+            remove: (...names) => names.forEach((n) => classes.delete(n)),
+            contains: (n) => classes.has(n),
+            toggle: () => false,
+        },
+        addEventListener: () => {},
+        querySelectorAll: () => [],
+        appendChild: () => {},
+    };
+    // Views reach for .parentElement to hide whole sections.
+    Object.defineProperty(el, "parentElement", {
+        get: () => node(id + "-parent"),
+    });
+    return el;
+}
+
+function makeDocument() {
+    const els = new Map();
+    return {
+        getElementById(id) {
+            // The debug banner is created on demand by helpers.js; absent
+            // is the state a non-debug, non-testnet popup is in.
+            if (id === "debug-banner") return null;
+            if (!els.has(id)) els.set(id, makeElement(id));
+            return els.get(id);
+        },
+        createElement: () => makeElement("created"),
+        body: { prepend: () => {} },
+    };
+}
+
+function node(id) {
+    return globalThis.document.getElementById(id);
+}
+
+// One line of the decoded details: its label and what is drawn under it.
+function decodedLine(label) {
+    return node("tx-detail-calldata-details")
+        .innerHTML.split('<div class="mb-2">')
+        .find((line) =>
+            line.startsWith(`<div class="text-muted">${label}</div>`),
+        );
+}
+
+beforeEach(() => {
+    globalThis.document = makeDocument();
+    globalThis.window = { location: { search: "" } };
+    state.blockscoutUrl = EXPLORER;
+    state.wallets = [
+        {
+            name: "Main",
+            type: "key",
+            addresses: [{ address: HOLDER, balance: "0.0000" }],
+        },
+    ];
+    state.trackedTokens = [{ address: TOKEN, symbol: "TDOL", decimals: 6 }];
+    state.viewData = {};
+    state.viewStack = [];
+    state.currentView = null;
+});
+
+test("a token transfer's decoded details name the token contract and the amount at its scale", async () => {
+    const [row] = await fetchRecentTransactions(HOLDER, EXPLORER, 1);
+    expect(row.to).toBe(RECIPIENT);
+    expect(row.contractAddress).toBe(TOKEN.toLowerCase());
+
+    transactionDetail.show(row);
+    // The decoded details are drawn once the explorer has answered.
+    for (let i = 0; i < 10; i++) await new Promise((r) => setTimeout(r, 0));
+
+    expect(node("tx-detail-calldata-action").textContent).toBe(
+        "Token Transfer",
+    );
+    const token = decodedLine("Token");
+    expect(token).toContain('<div class="font-bold">TDOL</div>');
+    expect(token).toContain(TOKEN);
+    expect(token).not.toContain(RECIPIENT);
+    expect(decodedLine("Recipient")).toContain(RECIPIENT);
+    expect(decodedLine("Amount")).toContain(
+        '<div class="font-bold">1234.5000 TDOL</div>',
+    );
+});

tests/uniswap.test.js

@@ -163,110 +163,6 @@ 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,
-    );
-}
-
 function detail(result, label) {
     return result.details.find((d) => d.label === label);
 }
@@ -307,45 +203,11 @@ 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).toBe("Permit2 Permit → V4 Swap");
+        expect(steps.value).toContain("Permit2 Permit");
+        expect(steps.value).toContain("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);
-        },
-    );
-
     test("decodes V2_SWAP_EXACT_IN with known tokens", () => {
         const data = buildExecute(
             "0x08", // V2_SWAP_EXACT_IN
@@ -686,11 +548,9 @@ 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 (could not be decoded) \u2192 Unwrap WETH",
+            "Permit2 Permit \u2192 V4 Swap \u2192 Unwrap WETH",
         );
     });