fix: a V4 swap action not in the deployed shape is shown as not decoded (closes #358)

The four V4 swap actions are read only as the structs deployed on mainnet
and Sepolia. ethers read the newer v4-periphery structs, which add
minHopPriceX36, as the deployed ones, 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 its SETTLE or TAKE did not name reads "Unknown
(could not be decoded)". The wait and error screens no longer show the
ETH value as the amount of a swap whose amount was not read, unless the
swap is paid in native ETH.

Model: opus-5-5

src/popup/views/approval.js

@@ -298,6 +298,23 @@ function showTxApproval(details) {
                 sources,
             );
         }
+        // A swap the decoder read no amount for, such as one whose V4 swap
+        // action could not be read or a V4 exact-out swap. The wait and error
+        // screens say the amount could not be decoded, with no currency after
+        // it, rather than show the transaction's ETH value as the amount. A
+        // swap paid in native ETH keeps that value: it is the ETH the swap
+        // pays (for an exact-out swap, the most it pays), not a figure that
+        // had to be read from the calldata.
+        const tokenIn = decoded.details.find((d) => d.label === "Token In");
+        if (
+            tokenIn &&
+            tokenIn.value !== "ETH (native)" &&
+            !decoded.details.some((d) => d.label === "Amount")
+        ) {
+            pendingTxDetails.amount = "Unknown (could not be decoded)";
+            pendingTxDetails.token = null;
+            pendingTxDetails.tokenSymbol = null;
+        }
     }
 
     // Carry decoded calldata info through to success/error views

src/popup/views/txStatus.js

@@ -91,12 +91,17 @@ function startWait(txInfo, txHash, broadcastTime, pollNow) {
     // native currency of txInfo.chainId, the network the transaction was sent
     // on, not the active network's: the active network can change, in
     // Settings or when the user approves a site's request, while this screen
-    // is open or before a later popup resumes it.
-    const symbol =
-        txInfo.token === "ETH"
-            ? nativeCurrencyByChainId(txInfo.chainId)
-            : displaySymbol(txInfo.tokenSymbol || "?");
-    $("wait-tx-summary").textContent = txInfo.amount + " " + symbol;
+    // is open or before a later popup resumes it. A null token is a swap whose
+    // amount was not decoded (see showTxApproval() in approval.js): the amount
+    // says so, and no symbol follows it.
+    let symbol = "";
+    if (txInfo.token === "ETH") {
+        symbol = nativeCurrencyByChainId(txInfo.chainId);
+    } else if (txInfo.token !== null) {
+        symbol = displaySymbol(txInfo.tokenSymbol || "?");
+    }
+    $("wait-tx-summary").textContent =
+        txInfo.amount + (symbol ? " " + symbol : "");
     $("wait-tx-to").innerHTML = toAddressHtml(txInfo.to);
     $("wait-tx-hash").innerHTML = txHashHtml(txHash);
     attachCopyHandlers("view-wait-tx");
@@ -231,10 +236,13 @@ function restoreWait() {
 function showSuccess(txInfo, txHash, blockNumber) {
     endWait();
 
-    const symbol =
-        txInfo.token === "ETH"
-            ? nativeCurrencyByChainId(txInfo.chainId)
-            : displaySymbol(txInfo.tokenSymbol || "?");
+    // As on the wait screen, a null token has no symbol.
+    let symbol = "";
+    if (txInfo.token === "ETH") {
+        symbol = nativeCurrencyByChainId(txInfo.chainId);
+    } else if (txInfo.token !== null) {
+        symbol = displaySymbol(txInfo.tokenSymbol || "?");
+    }
     state.viewData = {
         amount: txInfo.amount,
         symbol: symbol,
@@ -294,7 +302,8 @@ function renderSuccess() {
     } else {
         summarySection.classList.remove("hidden");
         toSection.classList.remove("hidden");
-        $("success-tx-summary").textContent = d.amount + " " + d.symbol;
+        $("success-tx-summary").textContent =
+            d.amount + (d.symbol ? " " + d.symbol : "");
         $("success-tx-to").innerHTML = toAddressHtml(d.to);
     }
 
@@ -317,10 +326,13 @@ function renderSuccess() {
 function showError(txInfo, txHash, message) {
     endWait();
 
-    const symbol =
-        txInfo.token === "ETH"
-            ? nativeCurrencyByChainId(txInfo.chainId)
-            : displaySymbol(txInfo.tokenSymbol || "?");
+    // As on the wait screen, a null token has no symbol.
+    let symbol = "";
+    if (txInfo.token === "ETH") {
+        symbol = nativeCurrencyByChainId(txInfo.chainId);
+    } else if (txInfo.token !== null) {
+        symbol = displaySymbol(txInfo.tokenSymbol || "?");
+    }
     state.viewData = {
         amount: txInfo.amount,
         symbol: symbol,
@@ -334,7 +346,8 @@ function showError(txInfo, txHash, message) {
 function renderError() {
     const d = state.viewData;
     if (!d || !d.message) return;
-    $("error-tx-summary").textContent = d.amount + " " + d.symbol;
+    $("error-tx-summary").textContent =
+        d.amount + (d.symbol ? " " + d.symbol : "");
     $("error-tx-to").innerHTML = toAddressHtml(d.to);
     $("error-tx-message").textContent = d.message;