TODO.md

@@ -45,6 +45,17 @@ but the review is broader than any of them.
 
 # Completed Steps
 
+- 2026-08-23: A swap always names its output token
+  ([#346](https://git.eeqj.de/sneak/AutistMask/issues/346)). The `Token Out`
+  detail line in `src/shared/uniswap.js` was pushed only when a symbol was
+  known, so a swap whose output token is absent from the bundled list — every
+  newly listed token — showed a `Min. received` figure with nothing saying what
+  was being received. The line is now keyed on the token's address and falls
+  back to it when there is no symbol, exactly as the `Token In` line already
+  did. It composes with the unknown-scale refusal from
+  [#340](https://git.eeqj.de/sneak/AutistMask/issues/340): the address says
+  which token, the base-unit figure says how much and states that the scale is
+  unknown.
 - 2026-08-23: The swap approval screen no longer guesses 18 decimals for a token
   outside the bundled list
   ([#340](https://git.eeqj.de/sneak/AutistMask/issues/340)). `tokenInfo()` in

src/shared/uniswap.js

@@ -496,20 +496,23 @@ function decode(data, toAddress, sources) {
             });
         }
 
-        if (outSymbol) {
-            if (outInfo.address) {
-                const label = outSymbol
-                    ? outSymbol + " (" + outputToken + ")"
-                    : outputToken;
-                details.push({
-                    label: "Token Out",
-                    value: label,
-                    address: outputToken,
-                    isToken: true,
-                });
-            } else {
-                details.push({ label: "Token Out", value: outSymbol });
-            }
+        // Keyed on the address, not the symbol: a token absent from the
+        // bundled list has no symbol, and gating the line on one dropped it
+        // entirely, leaving a Min. received figure with nothing saying what is
+        // being received. The Token In line above already falls back to the
+        // address; this does the same.
+        if (outInfo.address) {
+            const label = outSymbol
+                ? outSymbol + " (" + outInfo.address + ")"
+                : outInfo.address;
+            details.push({
+                label: "Token Out",
+                value: label,
+                address: outInfo.address,
+                isToken: true,
+            });
+        } else if (outSymbol) {
+            details.push({ label: "Token Out", value: outSymbol });
         }
 
         if (minOutput !== null && minOutput !== undefined) {

tests/uniswapTokenOut.test.js

@@ -0,0 +1,107 @@
+// The output token of a swap, as the dApp approval screen names it.
+//
+// Issue #346: the `Token Out` detail line in `src/shared/uniswap.js` was
+// pushed only `if (outSymbol)`, and a token absent from the bundled list has
+// no symbol. The line was therefore dropped entirely for exactly that
+// population — which is every newly listed token — leaving a `Min. received`
+// figure with nothing on the screen saying what is being received. The
+// `Token In` line already falls back to the address; the rule asserted here is
+// that the output side does too, always.
+
+const { AbiCoder, Interface, getAddress } = require("ethers");
+const uniswap = require("../src/shared/uniswap");
+const { unknownDecimalsAmount } = require("../src/shared/approvalAmount");
+
+const ROUTER = "0x66a9893cc07d91d95644aedd05d03f95e1dba8af";
+const RECIPIENT = "0xC0FfEE0000000000000000000000000000c0fFEe";
+// In the bundled list, at 18 decimals.
+const WETH = "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2";
+// Outside it, as every newly listed token is. Checksummed, because that is
+// the form the decoder gets back from the ABI decode and puts on the line.
+const NOVEL_OUT = getAddress("0xd0d0000000000000000000000000000000000d0d");
+
+const HALF_WETH = 500000000000000000n;
+// 1,000.00 of a 6-decimal token.
+const THOUSAND_AT_SIX = 1000000000n;
+
+const coder = AbiCoder.defaultAbiCoder();
+const routerIface = new Interface([
+    "function execute(bytes commands, bytes[] inputs, uint256 deadline)",
+]);
+
+// A V2_SWAP_EXACT_IN (command 0x08) execute() call.
+function swapData(tokenIn, amountIn, tokenOut, amountOutMin) {
+    const input = coder.encode(
+        ["address", "uint256", "uint256", "address[]", "bool"],
+        [RECIPIENT, amountIn, amountOutMin, [tokenIn, tokenOut], true],
+    );
+    return routerIface.encodeFunctionData("execute", [
+        "0x08",
+        [input],
+        9999999999n,
+    ]);
+}
+
+// An UNWRAP_WETH (command 0x0c) execute() call: the output side is native ETH,
+// which has no contract address to name.
+function unwrapData() {
+    return routerIface.encodeFunctionData("execute", [
+        "0x0c",
+        [coder.encode(["address", "uint256"], [RECIPIENT, HALF_WETH])],
+        9999999999n,
+    ]);
+}
+
+function detail(data, label, sources) {
+    const decoded = uniswap.decode(data, ROUTER, sources || {});
+    return decoded.details.find((d) => d.label === label);
+}
+
+describe("a swap to a token absent from the bundled list", () => {
+    const data = () => swapData(WETH, HALF_WETH, NOVEL_OUT, THOUSAND_AT_SIX);
+
+    test("still renders a Token Out line, naming the address", () => {
+        const out = detail(data(), "Token Out");
+        expect(out).toBeDefined();
+        expect(out.value).toBe(NOVEL_OUT);
+        expect(out.address).toBe(NOVEL_OUT);
+        expect(out.isToken).toBe(true);
+    });
+
+    test("names the address alongside the unknown-scale refusal", () => {
+        // The same population hits both: no symbol, and no scale either. The
+        // address says which token, the base units say how much and admit the
+        // scale is unknown — neither line silently means something else.
+        expect(detail(data(), "Token Out").value).toBe(NOVEL_OUT);
+        expect(detail(data(), "Min. received").value).toBe(
+            unknownDecimalsAmount(THOUSAND_AT_SIX),
+        );
+    });
+
+    test("names the address when the scale is known but the symbol is not", () => {
+        const sources = {
+            trackedTokens: [
+                { address: NOVEL_OUT, symbol: "NOVEL", decimals: 6 },
+            ],
+        };
+        expect(detail(data(), "Token Out", sources).value).toBe(NOVEL_OUT);
+        expect(detail(data(), "Min. received", sources).value).toBe(
+            "1000.0000",
+        );
+    });
+});
+
+describe("the output tokens that already had a line keep it unchanged", () => {
+    test("a bundled token is named by symbol and address", () => {
+        const data = swapData(NOVEL_OUT, THOUSAND_AT_SIX, WETH, HALF_WETH);
+        const out = detail(data, "Token Out");
+        expect(out.value).toBe("WETH (" + WETH + ")");
+        expect(out.address).toBe(WETH);
+    });
+
+    test("an unwrap to native ETH is named ETH, with no address", () => {
+        const out = detail(unwrapData(), "Token Out");
+        expect(out.value).toBe("ETH");
+        expect(out.address).toBeUndefined();
+    });
+});