Add restart-to-update banner: waiting SW detected via watchForWaitingUpdate, explicit user opt-in applies SKIP_WAITING + reload (no auto mid-session claim, ARCH §8)

tests/unit/sw.test.ts

@@ -6,7 +6,11 @@
  */
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 import { readFileSync, existsSync } from "node:fs";
-import { registerSW, skipWaitingForUpdate } from "../../src/platform/sw/register.js";
+import {
+  registerSW,
+  skipWaitingForUpdate,
+  watchForWaitingUpdate,
+} from "../../src/platform/sw/register.js";
 
 const SW_PATH = "public/sw.js";
 
@@ -148,6 +152,68 @@ describe("SW registration — page bridge", () => {
   });
 });
 
+describe("watchForWaitingUpdate — restart-to-update discovery", () => {
+  function withController(controller: unknown): void {
+    Object.defineProperty(globalThis, "navigator", {
+      value: { serviceWorker: { controller } },
+      writable: true,
+      configurable: true,
+    });
+  }
+
+  it("no controller (first install) → never fires", () => {
+    withController(null);
+    const onWaiting = vi.fn();
+    const listeners: Record<string, () => void> = {};
+    const reg = {
+      waiting: { postMessage: vi.fn() },
+      addEventListener: (ev: string, cb: () => void) => {
+        listeners[ev] = cb;
+      },
+    } as unknown as ServiceWorkerRegistration;
+    watchForWaitingUpdate(reg, onWaiting);
+    expect(onWaiting).not.toHaveBeenCalled();
+    expect(listeners.updatefound).toBeUndefined();
+  });
+
+  it("already-waiting worker fires immediately", () => {
+    withController({ scriptURL: "/sw.js" });
+    const onWaiting = vi.fn();
+    const reg = {
+      waiting: { postMessage: vi.fn() },
+      addEventListener: vi.fn(),
+    } as unknown as ServiceWorkerRegistration;
+    watchForWaitingUpdate(reg, onWaiting);
+    expect(onWaiting).toHaveBeenCalledWith(reg);
+  });
+
+  it("updatefound → installed waiting worker fires", () => {
+    withController({ scriptURL: "/sw.js" });
+    const onWaiting = vi.fn();
+    let foundCb: (() => void) | undefined;
+    const stateCbs: (() => void)[] = [];
+    const installed = {
+      state: "installed",
+      addEventListener: (_ev: string, cb: () => void) => {
+        stateCbs.push(cb);
+      },
+    };
+    const reg = {
+      waiting: null as unknown,
+      installing: installed,
+      addEventListener: (ev: string, cb: () => void) => {
+        if (ev === "updatefound") foundCb = cb;
+      },
+    } as unknown as ServiceWorkerRegistration;
+    watchForWaitingUpdate(reg, onWaiting);
+    expect(onWaiting).not.toHaveBeenCalled();
+    foundCb?.();
+    (reg as { waiting: unknown }).waiting = { postMessage: vi.fn() };
+    for (const cb of stateCbs) cb();
+    expect(onWaiting).toHaveBeenCalledTimes(1);
+  });
+});
+
 describe("Cache safety — versioning and shell assets", () => {
   it("vite build injects hashed assets into precache manifest", () => {
     const viteConfig = readFileSync("vite.config.ts", "utf8");

tests/unit/update-banner.test.ts

@@ -0,0 +1,54 @@
+/**
+ * @vitest-environment jsdom
+ * "Restart to update" banner — appears once, apply fires the opt-in,
+ * Later removes it. Pure DOM: no SW, no storage, no network.
+ */
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { showUpdateBanner } from "../../src/ui/components/update-banner.js";
+
+beforeEach(() => {
+  document.body.replaceChildren();
+});
+
+function root(): HTMLElement {
+  const el = document.createElement("div");
+  document.body.append(el);
+  return el;
+}
+
+describe("update banner", () => {
+  it("renders banner with apply and dismiss once (idempotent)", () => {
+    const host = root();
+    showUpdateBanner(host, () => undefined);
+    showUpdateBanner(host, () => undefined);
+    expect(document.querySelectorAll(".update-banner").length).toBe(1);
+    expect(host.textContent).toContain("new version");
+    expect(host.querySelector(".update-banner__apply")?.textContent).toBe("Restart to update");
+  });
+
+  it("apply invokes the opt-in callback exactly once per click", () => {
+    const host = root();
+    const onApply = vi.fn();
+    showUpdateBanner(host, onApply);
+    host.querySelector(".update-banner__apply")?.dispatchEvent(new MouseEvent("click"));
+    expect(onApply).toHaveBeenCalledTimes(1);
+  });
+
+  it("Later removes the banner without calling apply", () => {
+    const host = root();
+    const onApply = vi.fn();
+    showUpdateBanner(host, onApply);
+    host.querySelector(".update-banner__dismiss")?.dispatchEvent(new MouseEvent("click"));
+    expect(document.querySelector(".update-banner")).toBeNull();
+    expect(onApply).not.toHaveBeenCalled();
+    // Re-show after dismiss is allowed (a later update can re-offer).
+    showUpdateBanner(host, onApply);
+    expect(document.querySelectorAll(".update-banner").length).toBe(1);
+  });
+
+  it("renders no raw HTML from anywhere (textContent-only)", () => {
+    const host = root();
+    showUpdateBanner(host, () => undefined);
+    expect(host.querySelector(".update-banner")?.innerHTML).not.toMatch(/<img|<script/);
+  });
+});