fix: two pages switching networks no longer lose tracked tokens (closes #701)

A page that had not yet taken another page's network switch could lose
tracked tokens.

- Its save of an added or removed token wrote its own network's list as
  the new network's list. saveState() now keeps the stored list. It
  merges the add or removal into the stored list of the page's own
  network in networkTrackedTokens.
- Its own switch in Settings wrote its old lists of tracked tokens per
  network over the stored ones. onChainSwitch() now first takes the
  stored switch with takeStoredNetwork(), and then switches from there.
- takeStoredNetwork() replaced the page's tracked tokens with the stored
  ones. It now keeps the page's unsaved change in the list of the page's
  network. This also fixes
  #706.

Model: opus-5-5

src/shared/state.js

@@ -455,6 +455,11 @@ function mergeNetworkEndpoints(base, ours, theirs) {
 // own UI scratch space, not data another page has any reason to share
 // membership of.
 //
+// One exception: when the stored record is on another network than this
+// page's, a save keeps the stored `trackedTokens`. It merges this page's change
+// into the list in `networkTrackedTokens` for this page's network, by contract
+// address.
+//
 // This does not make two pages that both change the SAME leaf concurrently
 // safe: last write wins on that one leaf, same as before. What it removes
 // is the cross-field (and now cross-membership-vs-leaf) clobber — a page
@@ -627,16 +632,33 @@ function saveState(beforeWrite) {
     return turn;
 }
 
-// Give this page the network switch held by `stored`, a record a save of this
+// Give this page the network switch held by `stored`, in `state` and in
-// page has just read (followStoredSettings() in src/popup/index.js and
+// `baseline` alike, as loadState() does with a whole record. `stored` is the
-// onChainSwitch() in src/shared/chainSwitch.js call this from `beforeWrite`),
+// record that a save of this page has just read. followStoredSettings() in
-// in `state` and in `baseline` alike, as loadState() does with a whole
+// src/popup/index.js and onChainSwitch() in src/shared/chainSwitch.js call this
-// record. The switch is then not this page's own change, even when that save
+// from `beforeWrite`. The switch is then not this page's own change, even when
-// fails to write: a later switch back to the previous network still differs
+// that save fails to write: a later switch back to the previous network still
-// from `baseline`, and is stored.
+// differs from `baseline`, and is stored.
+//
+// A token that this page tracked or removed since its last save was tracked or
+// removed on this page's network before the switch. `state` keeps that change
+// in the list in `networkTrackedTokens` for that network, merged with the
+// stored list by contract address. `baseline` takes the stored list, so the
+// save stores the change (https://git.eeqj.de/sneak/AutistMask/issues/706).
 function takeStoredNetwork(stored) {
+    const networkTrackedTokens = {
+        ...stored.networkTrackedTokens,
+        [rawState.networkId]: mergeListByIdentity(
+            baseline.trackedTokens,
+            rawState.trackedTokens,
+            stored.networkTrackedTokens[rawState.networkId],
+            (token) => token.address.toLowerCase(),
+            (base, ours) => ours,
+        ),
+    };
     copyChainSwitchFields(rawState, stored);
     copyChainSwitchFields(baseline, structuredClone(stored));
+    rawState.networkTrackedTokens = networkTrackedTokens;
 }
 
 // Give this page the tracked tokens of `stored`, a record on this page's

tests/trackedTokensPerNetwork.test.js

@@ -311,6 +311,43 @@ test("a token added before this page takes another page's switch is tracked on E
     ]);
 });
 
+// Another popup page tracks DAI on Ethereum Mainnet and then saves a switch to
+// Sepolia. This page does not track DAI. Before taking that switch, this page
+// adds a token on Ethereum Mainnet. The add's save puts both DAI and the new
+// token on Ethereum Mainnet's list.
+test("a token added before this page takes another page's switch joins that page's tokens on Ethereum Mainnet", async () => {
+    const boot = await bootOnAddToken("mainnet");
+    expect(boot.pageErrors).toEqual([]);
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        networkId: "sepolia",
+        trackedTokens: [],
+        networkTrackedTokens: { mainnet: [MAINNET_TOKEN] },
+    });
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    lookupTokenInfo.mockResolvedValueOnce({
+        symbol: "NEW",
+        decimals: 18,
+        name: "New Token",
+    });
+
+    boot.node("settings-addtoken-address").value = NEW_TOKEN_ADDRESS;
+    await boot.click("btn-settings-addtoken-manual");
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([
+        MAINNET_TOKEN,
+        {
+            address: NEW_TOKEN_ADDRESS,
+            symbol: "NEW",
+            decimals: 18,
+            name: "New Token",
+        },
+    ]);
+});
+
 // Another popup page saves a switch to Sepolia, where TST is tracked. Before
 // taking that switch, this page removes DAI on Ethereum Mainnet, as the `[x]`
 // on a tracked token in Settings does. The removal's save drops DAI from
@@ -436,6 +473,120 @@ test("a token added while a switch in Settings waits for the lock stays tracked
     ]);
 });
 
+// The contract lookup on SettingsAddToken answers on Ethereum Mainnet while
+// this page's switch to Sepolia waits for the lock. Another popup page holds
+// the lock and stores its own switch to Sepolia, with DAI tracked on Ethereum
+// Mainnet. This page's switch keeps DAI and the new token on Ethereum Mainnet's
+// list.
+test("a token added while a switch in Settings waits for another page's switch stays tracked on Ethereum Mainnet", async () => {
+    const boot = await bootOnAddToken("mainnet");
+    expect(boot.pageErrors).toEqual([]);
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    let answer;
+    lookupTokenInfo.mockImplementationOnce(
+        () =>
+            new Promise((resolve) => {
+                answer = resolve;
+            }),
+    );
+    boot.node("settings-addtoken-address").value = NEW_TOKEN_ADDRESS;
+    const adding = boot.click("btn-settings-addtoken-manual");
+    await boot.click("btn-settings");
+
+    let releaseLock;
+    const lockHeld = navigator.locks.request(
+        "autistmask",
+        () =>
+            new Promise((resolve) => {
+                releaseLock = resolve;
+            }),
+    );
+    const select = boot.node("settings-network");
+    select.value = "sepolia";
+    const switching = Promise.all(select.listeners.change.map((fn) => fn()));
+    await boot.settle();
+    boot.storage.write("autistmask", {
+        ...boot.storage.read("autistmask"),
+        networkId: "sepolia",
+        trackedTokens: [],
+        networkTrackedTokens: { mainnet: [MAINNET_TOKEN] },
+    });
+
+    answer({ symbol: "NEW", decimals: 18, name: "New Token" });
+    await boot.settle();
+    releaseLock();
+    await lockHeld;
+    await switching;
+    await adding;
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([
+        MAINNET_TOKEN,
+        {
+            address: NEW_TOKEN_ADDRESS,
+            symbol: "NEW",
+            decimals: 18,
+            name: "New Token",
+        },
+    ]);
+});
+
+// Another popup page holds the lock and stores its switch to Sepolia, with DAI
+// tracked on Ethereum Mainnet. This page waits for the lock to take that
+// switch. Meanwhile, the contract lookup on SettingsAddToken answers on
+// Ethereum Mainnet. When this page takes that switch, DAI and the new token
+// stay on Ethereum Mainnet's list.
+test("a token added while this page waits to take another page's switch stays tracked on Ethereum Mainnet", async () => {
+    const boot = await bootOnAddToken("mainnet");
+    expect(boot.pageErrors).toEqual([]);
+    let releaseLock;
+    const lockHeld = navigator.locks.request(
+        "autistmask",
+        () =>
+            new Promise((resolve) => {
+                releaseLock = resolve;
+            }),
+    );
+    await boot.storage.local.set({
+        autistmask: {
+            ...boot.storage.read("autistmask"),
+            networkId: "sepolia",
+            trackedTokens: [],
+            networkTrackedTokens: { mainnet: [MAINNET_TOKEN] },
+        },
+    });
+    await boot.settle();
+    const { lookupTokenInfo } = require("../src/shared/balances");
+    lookupTokenInfo.mockResolvedValueOnce({
+        symbol: "NEW",
+        decimals: 18,
+        name: "New Token",
+    });
+
+    boot.node("settings-addtoken-address").value = NEW_TOKEN_ADDRESS;
+    const adding = boot.click("btn-settings-addtoken-manual");
+    await boot.settle();
+    releaseLock();
+    await lockHeld;
+    await adding;
+    await boot.settle();
+
+    const stored = boot.storage.read("autistmask");
+    expect(stored.networkId).toBe("sepolia");
+    expect(stored.trackedTokens).toEqual([]);
+    expect(stored.networkTrackedTokens.mainnet).toEqual([
+        MAINNET_TOKEN,
+        {
+            address: NEW_TOKEN_ADDRESS,
+            symbol: "NEW",
+            decimals: 18,
+            name: "New Token",
+        },
+    ]);
+});
+
 describe("Back after a switch from the Settings gear", () => {
     test("SettingsAddToken no longer offers the common tokens", async () => {
         const boot = await bootOnAddToken("mainnet");