Theseus: an extension update applied in place reloads its open panels

Applying an extension update without a restart swapped the files and
restarted the add-on, but a panel or tab that was already open kept
running the previous version's page, so the extension looked unchanged
until Theseus restarted (Pithos showed its old layout this way). The
add-on's open left panel, sidebar panel and tabs now reload after the
swap. Extensions can also apply their own staged update with
api.applySelfUpdate(), so their own update button needs no restart;
plug-ins such as wallets still update on the next launch.

addons-host.js

@@ -282,7 +282,7 @@ function validateManifest(raw, folderName) {
 // Loader singleton. `discoverAndActivate(opts)` returns a snapshot the rest
 // of the app queries via `getActive()` / `getInstalled()`.
 class AddonHost {
-  constructor({ addonsDir, dataDir, isDisabled, activationFor, onActivated, logger, setSessionProxy, vaultDerive, vaultImports, approvalModal, emitToPanel, hostRequire, hostImport, openTab, openAddonTab, openSettings, captureTab, saveCapture, scanTabForUris, checkAndStageUpdates, restartApp, revealSidebar, requestFilter, tabs }) {
+  constructor({ addonsDir, dataDir, isDisabled, activationFor, onActivated, logger, setSessionProxy, vaultDerive, vaultImports, approvalModal, emitToPanel, hostRequire, hostImport, openTab, openAddonTab, openSettings, captureTab, saveCapture, scanTabForUris, checkAndStageUpdates, restartApp, applySelfUpdate, revealSidebar, requestFilter, tabs }) {
     this.addonsDir = addonsDir;
     this.dataDir = dataDir;
     this.isDisabled = isDisabled || (() => false);
@@ -351,6 +351,7 @@ class AddonHost {
     // add-on ever gets to hand-write into its own installed folder.
     this._checkAndStageUpdates = typeof checkAndStageUpdates === "function" ? checkAndStageUpdates : null;
     this._restartApp = typeof restartApp === "function" ? restartApp : null;
+    this._applySelfUpdate = typeof applySelfUpdate === "function" ? applySelfUpdate : null;
     // revealSidebar: opens the sidebar and switches to the given panel id.
     // Signature: (addonId, panelId) => void. Add-ons use this from their
     // context-menu handler to surface a result in their sidebar UI.
@@ -837,6 +838,13 @@ class AddonHost {
           staged: (full?.staged || []).find((s) => s.id === manifest.id) || null,
         };
       },
+      // Apply this add-on's staged update now, without a restart: Theseus
+      // swaps it in, restarts the add-on and reloads its open panels and
+      // tabs. Plug-ins (wallets) still update on the next launch.
+      applySelfUpdate: async () => {
+        if (!this._applySelfUpdate) throw new Error("applySelfUpdate unavailable (host not wired)");
+        return this._applySelfUpdate(manifest.id);
+      },
       // Ask Theseus to relaunch (the plug-in card's "apply update" chip).
       // The host asks the user first and resolves { restarted, deferred }
       // — an add-on cannot restart the browser on its own.

main.js

@@ -2746,6 +2746,15 @@ function initAddons() {
     // update) but never gets to perform one: the user is asked first, in a
     // native dialog the panel cannot draw over. Declining costs nothing —
     // a staged update applies on the next normal launch anyway.
+    // An add-on applying its own staged update in place (no restart). Runs a
+    // moment later so the add-on's own call can return before the host is
+    // rebuilt underneath it.
+    applySelfUpdate: (addonId) => {
+      if (isPluginAddon(addonId)) return { ok: false, reason: "plug-ins update on the next launch" };
+      if (!listStagedAddons(addonsStagedDir()).some((s) => s.id === addonId)) return { ok: false, reason: "nothing staged" };
+      setTimeout(() => applyStagedNow(addonId), 250);
+      return { ok: true, scheduled: true };
+    },
     restartApp: async (addonName) => {
       const who = String(addonName || "An add-on").slice(0, 60);
       console.log(`[restart] ${who} asked to relaunch Theseus`);
@@ -5924,9 +5933,9 @@ ipcMain.handle("addons-check-updates", () => pollAddonUpdates("manual"));
 // launch — a wallet mid-session is not something to hot-swap. `id` limits
 // the apply to one extension (Settings row button); omitted = every
 // staged extension (toolbar chip).
-ipcMain.handle("addons-apply-staged", (_e, id) => {
+ipcMain.handle("addons-apply-staged", (_e, id) => applyStagedNow(typeof id === "string" && id ? id : null));
+function applyStagedNow(want) {
   if (!addonHost) return { ok: false, error: "add-ons not ready", applied: [] };
-  const want = typeof id === "string" && id ? id : null;
   const applied = addonUpdater.promoteStagedUpdates({
     addonsDir: addonsUserDir(),
     backupsDir: addonsBackupDir(),
@@ -5934,10 +5943,36 @@ ipcMain.handle("addons-apply-staged", (_e, id) => {
     logger: (...a) => console.log("[addons]", ...a),
     only: (m) => (want ? m.id === want : true) && !isPluginAddon(m.id),
   });
-  if (applied.length) { addonHost.discoverAndActivate(); emitSidebarState(); }
+  if (applied.length) {
+    addonHost.discoverAndActivate();
+    emitSidebarState();
+    reloadAddonViews(applied.map((a) => a.id || a));
+  }
   notifyStagedAddons();
   return { ok: true, applied, pending: listStagedAddons(addonsStagedDir()).map((s) => ({ id: s.id, version: s.version })) };
-});
+}
+// After an update is applied in place, an open panel or tab of that add-on
+// still runs the previous version's page (it was loaded before the swap),
+// so it shows the old UI until Theseus restarts. Reload them from disk.
+function reloadAddonViews(ids) {
+  const mine = (panelId) => panelId && ids.some((id) => String(panelId).startsWith(`${id}:`));
+  try {
+    if (mine(leftPanelLoadedId)) {
+      const open = leftPanelId;
+      leftPanelLoadedId = null;
+      if (open && mine(open)) openLeftPanel(open);
+    }
+  } catch (e) { console.warn("[addons] left panel reload failed:", e?.message); }
+  try {
+    if (mine(sidebarActivePanelId) && sidebar) {
+      const p = addonHost.getSidebarPanels().find((x) => x.panelId === sidebarActivePanelId);
+      if (p) sidebar.webContents.loadFile(p.pageFile);
+    }
+  } catch (e) { console.warn("[addons] sidebar reload failed:", e?.message); }
+  for (const t of tabs) {
+    try { if (t.addonId && ids.includes(t.addonId)) t.view.webContents.reload(); } catch {}
+  }
+}
 ipcMain.handle("addons-list-staged", () => listStagedAddons(addonsStagedDir()));
 function listStagedAddons(stagedDir) {
   const out = [];