fix: a token lookup that answers after the user left AddToken no longer changes the screen (closes #603)

When the contract lookup on AddToken answered, the popup went to AddressDetail even after the user had opened another screen. It now goes there only while AddToken shows and has not been opened again since Add was pressed; AddToken counts its openings as Send does. The token is still added as before unless the network changed. An answer, found or failed, from an earlier opening leaves the screen and the status line alone, so a later lookup's "Looking up token..." stays.

Judgement call: a user who went Back to AddressDetail during the lookup sees the new token once that screen is drawn again.

Model: opus-5-5

src/popup/views/addToken.js

@@ -5,7 +5,12 @@ const { lookupTokenInfo } = require("../../shared/balances");
 const { isScamAddress } = require("../../shared/scamlist");
 const { log } = require("../../shared/log");
 
+// Counts the times AddToken has opened. A contract lookup started before
+// AddToken was last opened changes neither the screen nor the status line.
+let addTokenScreenOpenings = 0;
+
 function show() {
+    addTokenScreenOpenings++;
     $("add-token-address").value = "";
     $("add-token-info").textContent = "";
     $("add-token-info").style.visibility = "hidden";
@@ -55,6 +60,7 @@ function init(ctx) {
         // The network the lookup asks, which Settings may switch away from
         // before it answers, as for a transaction in confirmTx.js.
         const chainId = currentNetwork().chainId;
+        const opening = addTokenScreenOpenings;
         try {
             const info = await lookupTokenInfo(
                 contractAddr,
@@ -80,6 +86,17 @@ function init(ctx) {
             });
             await saveState();
             ctx.doRefreshAndRender();
+            // If the lookup answers after AddToken was opened again, the
+            // token is still added, but the screen and the status line stay
+            // as they are.
+            if (addTokenScreenOpenings !== opening) return;
+            // The lookup is over, so a later Back onto AddToken shows no
+            // status.
+            infoEl.textContent = "";
+            infoEl.style.visibility = "hidden";
+            // If the lookup answers while another screen shows, the token is
+            // still added but the screen does not change.
+            if (state.currentView !== "add-token") return;
             // Pop the stack (back to address detail) and re-render it
             // so the newly added token is visible immediately.
             if (state.viewStack.length > 0) {
@@ -100,6 +117,7 @@ function init(ctx) {
                     ? detail
                     : "Could not add the token.",
             );
+            if (addTokenScreenOpenings !== opening) return;
             infoEl.textContent = "";
             infoEl.style.visibility = "hidden";
         }