fix(desktop): keep windows if update install fails

apps/desktop/src/updates/DesktopUpdates.test.ts

@@ -31,6 +31,7 @@ interface UpdatesHarnessOptions {
   readonly setUpdateChannelError?: DesktopAppSettings.DesktopSettingsWriteError;
   readonly setDisableDifferentialDownload?: Effect.Effect<void>;
   readonly stopBackend?: Effect.Effect<void>;
+  readonly quitAndInstall?: Effect.Effect<void, ElectronUpdater.ElectronUpdaterQuitAndInstallError>;
   readonly env?: Record<string, string | undefined>;
 }
 
@@ -43,6 +44,7 @@ function makeHarness(options: UpdatesHarnessOptions = {}) {
   const feedUrls: ElectronUpdater.ElectronUpdaterFeedUrl[] = [];
   const listeners = new Map<string, Set<(...args: readonly unknown[]) => void>>();
   const sentStates: DesktopUpdateState[] = [];
+  const installSteps: string[] = [];
 
   const addListener = (eventName: string, listener: (...args: readonly unknown[]) => void) => {
     const eventListeners = listeners.get(eventName) ?? new Set();
@@ -84,7 +86,10 @@ function makeHarness(options: UpdatesHarnessOptions = {}) {
       checkCount += 1;
     }).pipe(Effect.andThen(options.checkForUpdates ?? Effect.void)),
     downloadUpdate: Effect.void,
-    quitAndInstall: () => Effect.void,
+    quitAndInstall: () =>
+      Effect.sync(() => {
+        installSteps.push("quitAndInstall");
+      }).pipe(Effect.andThen(options.quitAndInstall ?? Effect.void)),
     on: (eventName, listener) =>
       Effect.acquireRelease(
         Effect.sync(() => {
@@ -109,14 +114,18 @@ function makeHarness(options: UpdatesHarnessOptions = {}) {
       Effect.sync(() => {
         sentStates.push(state as DesktopUpdateState);
       }),
-    destroyAll: Effect.void,
+    destroyAll: Effect.sync(() => {
+      installSteps.push("destroyAll");
+    }),
     syncAllAppearance: () => Effect.void,
   } satisfies ElectronWindow.ElectronWindow["Service"]);
 
   const stubBackendInstance: DesktopBackendPool.DesktopBackendInstance = {
     id: DesktopBackendPool.PRIMARY_INSTANCE_ID,
     label: Effect.succeed("Windows"),
-    start: Effect.void,
+    start: Effect.sync(() => {
+      installSteps.push("startBackend");
+    }),
     stop: () => options.stopBackend ?? Effect.void,
     currentConfig: Effect.succeed(Option.none()),
     snapshot: Effect.succeed({
@@ -219,6 +228,7 @@ function makeHarness(options: UpdatesHarnessOptions = {}) {
         0,
       ),
     sentStates,
+    installSteps,
     emit: (eventName: string, payload?: unknown) => {
       for (const listener of listeners.get(eventName) ?? []) {
         listener(payload);
@@ -725,6 +735,56 @@ describe("DesktopUpdates", () => {
     ).pipe(Effect.provide(Layer.merge(TestClock.layer(), harness.layer)));
   });
 
+  it.effect("destroys windows only after quitAndInstall starts", () => {
+    const harness = makeHarness();
+
+    return Effect.scoped(
+      Effect.gen(function* () {
+        const updates = yield* DesktopUpdates.DesktopUpdates;
+        yield* updates.configure;
+        harness.emit("update-downloaded", { version: "1.2.4" });
+        yield* flushCallbacks;
+
+        const result = yield* updates.install;
+        assert.isTrue(result.accepted);
+        assert.deepEqual(harness.installSteps, ["quitAndInstall", "destroyAll"]);
+      }),
+    ).pipe(Effect.provide(Layer.merge(TestClock.layer(), harness.layer)));
+  });
+
+  it.effect("keeps windows when quitAndInstall fails", () => {
+    const harness = makeHarness({
+      quitAndInstall: Effect.fail(
+        new ElectronUpdater.ElectronUpdaterQuitAndInstallError({
+          channel: null,
+          isSilent: true,
+          isForceRunAfter: true,
+          cause: new Error("installer refused"),
+        }),
+      ),
+    });
+
+    return Effect.scoped(
+      Effect.gen(function* () {
+        const desktopState = yield* DesktopState.DesktopState;
+        const updates = yield* DesktopUpdates.DesktopUpdates;
+        yield* updates.configure;
+        harness.emit("update-downloaded", { version: "1.2.4" });
+        yield* flushCallbacks;
+
+        const result = yield* updates.install;
+        assert.isTrue(result.accepted);
+        assert.isFalse(result.completed);
+        assert.isFalse(yield* Ref.get(desktopState.quitting));
+        assert.deepEqual(harness.installSteps, ["quitAndInstall", "startBackend"]);
+
+        const failedState = yield* updates.getState;
+        assert.equal(failedState.status, "downloaded");
+        assert.equal(failedState.errorContext, "install");
+      }),
+    ).pipe(Effect.provide(Layer.merge(TestClock.layer(), harness.layer)));
+  });
+
   it.effect("persists channel changes through the settings service", () => {
     const harness = makeHarness();
 

apps/desktop/src/updates/DesktopUpdates.ts

@@ -483,6 +483,11 @@ export const make = Effect.gen(function* () {
 
     yield* Ref.set(desktopState.quitting, true);
 
+    const instances = yield* pool.list;
+    const restartStoppedBackends = Effect.forEach(instances, (instance) => instance.start, {
+      concurrency: "unbounded",
+    }).pipe(Effect.asVoid);
+
     return yield* Effect.gen(function* () {
       // Stop every backend in the pool, not just the primary. With
       // parallel WSL + Windows backends, leaving the WSL instance up
@@ -491,23 +496,25 @@ export const make = Effect.gen(function* () {
       // WSL child gets hard-killed by the OS instead of receiving
       // SIGTERM + grace. Stops run concurrently with the same 5s
       // budget the primary had on its own.
-      const instances = yield* pool.list;
       yield* Effect.forEach(
         instances,
         (instance) => instance.stop({ timeout: Duration.seconds(5) }),
         { concurrency: "unbounded" },
       );
-      yield* electronWindow.destroyAll;
       yield* electronUpdater.quitAndInstall({
         isSilent: true,
         isForceRunAfter: true,
       });
+      // Close windows only after quitAndInstall has started. If install
+      // fails, the user still has a window.
+      yield* electronWindow.destroyAll;
       return { accepted: true, completed: false };
     }).pipe(
       Effect.catchTags({
         ElectronUpdaterQuitAndInstallError: Effect.fn("desktop.updates.handleInstallFailure")(
           function* (error) {
             yield* resetInstallAction;
+            yield* restartStoppedBackends;
             yield* updateState((current) =>
               reduceDesktopUpdateStateOnInstallFailure(current, error.message),
             );
@@ -528,6 +535,7 @@ export const make = Effect.gen(function* () {
             return yield* Effect.failCause(cause);
           }
           yield* resetInstallAction;
+          yield* restartStoppedBackends;
           const error = new DesktopUpdateUnexpectedActionError({ action: "install", cause });
           yield* updateState((current) =>
             reduceDesktopUpdateStateOnInstallFailure(current, error.message),