fix: a transaction history that lands after a network switch is dropped (closes #657)

Home, AddressDetail and AddressToken remember which network is active
before they ask Blockscout for the transaction history. Each screen drops
the answer if another network is active on the page or in storage when the
answer lands. AddressDetail and AddressToken also drop an answer that lands
once the screen shows another address. AddressToken also drops an answer
that lands once the screen shows another token.

A dropped answer draws no rows and saves no fraud contracts. A failed
request goes through the same checks. A dropped failure shows no message.
Holding the lock, the save adds new fraud contracts only if the page and
the stored record still name the request's network.

storedNetworkIs() reads the stored network, in src/shared/storedSettings.js.

Model: opus-5-5

src/popup/views/addressToken.js

@@ -29,6 +29,7 @@ const {
     filterTransactions,
 } = require("../../shared/transactions");
 const { resolveEnsNames } = require("../../shared/ens");
+const { storedNetworkIs } = require("../../shared/storedSettings");
 const {
     updateSendBalance,
     renderSendTokenSelect,
@@ -170,6 +171,7 @@ function show() {
 }
 
 async function loadTransactions(address, tokenId) {
+    const networkId = state.networkId;
     try {
         const rawTxs = await fetchRecentTransactions(
             address,
@@ -186,16 +188,6 @@ async function loadTransactions(address, tokenId) {
         });
         let txs = result.transactions;
 
-        // Persist any newly discovered fraud contracts
-        if (result.newFraudContracts.length > 0) {
-            for (const addr of result.newFraudContracts) {
-                if (!state.fraudContracts.includes(addr)) {
-                    state.fraudContracts.push(addr);
-                }
-            }
-            await saveState();
-        }
-
         // Filter to this token only
         if (tokenId === "ETH") {
             txs = txs.filter((tx) => tx.contractAddress === null);
@@ -207,32 +199,75 @@ async function loadTransactions(address, tokenId) {
             );
         }
 
-        loadedTxs = txs;
-
         // Collect ALL unique addresses for ENS resolution so reverse
         // lookups work for every displayed address.
         const counterparties = [
             ...new Set(txs.flatMap((tx) => [tx.from, tx.to].filter(Boolean))),
         ];
+        let names = new Map();
         if (counterparties.length > 0) {
             try {
-                ensNameMap = await resolveEnsNames(
+                names = await resolveEnsNames(
                     counterparties,
                     state.rpcUrl,
                     state.networkId,
                     ctx.pageClosed,
                 );
             } catch {
-                ensNameMap = new Map();
+                // The rows then show no ENS names.
             }
         }
 
+        // If the network changed during the lookups above, or the screen now
+        // shows another address or token, nothing is saved or drawn. See
+        // src/shared/storedSettings.js.
+        if (
+            state.networkId !== networkId ||
+            !(await storedNetworkIs(networkId)) ||
+            $("address-token-line").dataset.full !== address ||
+            state.selectedToken !== tokenId
+        ) {
+            return;
+        }
+
+        // Persist any newly discovered fraud contracts, inside the save and
+        // holding the lock. Nothing is added unless this page and the stored
+        // record both still name the request's network.
+        if (result.newFraudContracts.length > 0) {
+            let saved = false;
+            await saveState((stored) => {
+                if (state.networkId !== networkId) return false;
+                if (stored.networkId !== networkId) return false;
+                for (const addr of result.newFraudContracts) {
+                    if (!state.fraudContracts.includes(addr)) {
+                        state.fraudContracts.push(addr);
+                    }
+                }
+                saved = true;
+            });
+            // If the network changed while the save waited for the lock,
+            // nothing is drawn.
+            if (!saved) return;
+        }
+
+        loadedTxs = txs;
+        ensNameMap = names;
         renderTransactions(txs);
     } catch (e) {
         // Cancelled by the popup closing, not failed: see pageClosed in
         // src/popup/index.js.
         if (ctx.pageClosed.aborted) return;
         log.errorf("loadTransactions failed:", e.message);
+        // If the network changed, or the screen now shows another address or
+        // token, the failure is not shown.
+        if (
+            state.networkId !== networkId ||
+            !(await storedNetworkIs(networkId)) ||
+            $("address-token-line").dataset.full !== address ||
+            state.selectedToken !== tokenId
+        ) {
+            return;
+        }
         $("address-token-tx-list").innerHTML =
             '<div class="text-muted text-xs py-1">Failed to load transactions.</div>';
     }