test(config): harden client recovery paths

apps/desktop/e2e/config-canary.e2e.mts

@@ -8,10 +8,15 @@ import { join } from 'node:path';
 import { noop } from 'foxts/noop';
 import { wait } from 'foxts/wait';
 import type { ElectronApplication } from 'playwright-core';
-import type { DistServer, ServerMode } from './config-canary/dist-server.mts';
-import { startDistServer, waitForRequest } from './config-canary/dist-server.mts';
+import type { DistServer, EmergencyServerMode, ServerMode } from './config-canary/dist-server.mts';
+import {
+  startDistServer,
+  startEmergencyServer,
+  waitForRequest,
+} from './config-canary/dist-server.mts';
 import {
   buildDesktopWithBootstrap,
+  EMERGENCY_PORT,
   generateTlsMaterial,
   launchApp,
   PORT,
@@ -21,18 +26,21 @@ import { baseline, canary, rollback, rollForward } from './config-canary/fixture
 import type { ConfigStateFile } from './config-canary/state-file.mts';
 import {
   readConfigState,
+  readEmergencyState,
   waitForConfigState,
   writeCorruptConfigState,
 } from './config-canary/state-file.mts';
 
 const REJECTION_SETTLE_MS = 1000;
 
 let mode: ServerMode = 'offline';
+let emergencyMode: EmergencyServerMode = 'offline';
 
 interface Harness {
   app: ElectronApplication | null;
   readonly caCert: string;
   readonly dist: DistServer;
+  readonly emergency: DistServer;
   readonly home: string;
   readonly userData: string;
 }
@@ -199,6 +207,106 @@ async function driveScenarios(harness: Harness): Promise<void> {
     assertAccepted(state, baseline);
     console.log('PASS baseline republication recovers after corrupt-state reset');
   });
+
+  emergencyMode = 'kill-switch';
+  harness.emergency.requests.length = 0;
+  await withLaunch(harness, 'offline', async () => {
+    const app = assertApp(harness);
+    const boundary = await refreshBoundary(app);
+    assert.equal(boundary.report.normal, 'error');
+    assert.equal(boundary.report.emergency, 'updated');
+    const emergency = boundary.info.emergency;
+    assert(emergency);
+    assert.deepEqual(emergency.disabledFeatures, ['feature.aiAssist']);
+    assert.equal(emergency.emergencyVersion, '1');
+    await waitForRequest(
+      harness.dist,
+      (request) => request.path === baseline.pointerPath && request.status === 'disconnected',
+    );
+    await waitForRequest(
+      harness.emergency,
+      (request) => request.mode === 'kill-switch' && request.status === 200,
+    );
+    console.log('PASS emergency origin activates kill switch during main-channel outage');
+  });
+
+  emergencyMode = 'forced-minimum';
+  harness.emergency.requests.length = 0;
+  await withLaunch(harness, 'offline', async () => {
+    const boundary = await refreshBoundary(assertApp(harness));
+    assert.equal(boundary.report.emergency, 'updated');
+    const emergency = boundary.info.emergency;
+    assert(emergency);
+    assert.equal(emergency.emergencyVersion, '2');
+    assert.equal(emergency.forceMinVersion, '2.4.0');
+    console.log('PASS newer emergency state replaces the persisted kill switch');
+  });
+
+  emergencyMode = 'offline';
+  harness.emergency.requests.length = 0;
+  await withLaunch(harness, 'offline', async () => {
+    const boundary = await refreshBoundary(assertApp(harness));
+    assert.equal(boundary.report.emergency, 'error');
+    const emergency = boundary.info.emergency;
+    assert(emergency);
+    assert.equal(emergency.emergencyVersion, '2');
+    assert.equal(emergency.forceMinVersion, '2.4.0');
+    console.log('PASS forced minimum survives reconstructed runtime and emergency outage');
+  });
+
+  emergencyMode = 'release';
+  harness.emergency.requests.length = 0;
+  let releaseRaw = '';
+  await withLaunch(harness, 'offline', async () => {
+    const boundary = await refreshBoundary(assertApp(harness));
+    assert.equal(boundary.report.emergency, 'updated');
+    const emergency = boundary.info.emergency;
+    assert(emergency);
+    assert.deepEqual(emergency.disabledFeatures, []);
+    assert.equal(emergency.emergencyVersion, '3');
+    releaseRaw = (await readEmergencyState(harness.home))?.raw ?? '';
+    assert(releaseRaw);
+    console.log('PASS explicit newer release clears emergency restrictions');
+  });
+
+  emergencyMode = 'equivocation';
+  harness.emergency.requests.length = 0;
+  await withLaunch(harness, 'offline', async () => {
+    const boundary = await refreshBoundary(assertApp(harness));
+    assert.equal(boundary.report.emergency, 'error');
+    const emergency = boundary.info.emergency;
+    assert(emergency);
+    assert.deepEqual(emergency.disabledFeatures, []);
+    assert.equal(emergency.emergencyVersion, '3');
+    assert.equal((await readEmergencyState(harness.home))?.raw, releaseRaw);
+    console.log('PASS equal-version emergency equivocation cannot replace explicit release');
+  });
+
+  emergencyMode = 'offline';
+  harness.emergency.requests.length = 0;
+  await withLaunch(harness, 'offline', async () => {
+    const boundary = await refreshBoundary(assertApp(harness));
+    assert.equal(boundary.report.emergency, 'error');
+    const emergency = boundary.info.emergency;
+    assert(emergency);
+    assert.deepEqual(emergency.disabledFeatures, []);
+    assert.equal(emergency.emergencyVersion, '3');
+    assert.equal((await readEmergencyState(harness.home))?.raw, releaseRaw);
+    console.log('PASS explicit release remains sticky across reconstructed runtime and outage');
+  });
+}
+
+function assertApp(harness: Harness): ElectronApplication {
+  assert(harness.app);
+  return harness.app;
+}
+
+async function refreshBoundary(app: ElectronApplication) {
+  const page = await app.firstWindow();
+  return page.evaluate(async () => {
+    const report = await window.linkcodeConfig.refresh();
+    return { info: window.linkcodeConfig.snapshotInfo(), report };
+  });
 }
 
 async function main(): Promise<void> {
@@ -210,7 +318,8 @@ async function main(): Promise<void> {
     const tls = generateTlsMaterial(scratch);
     buildDesktopWithBootstrap();
     const dist = await startDistServer(tls, PORT, () => mode);
-    harness = { app: null, caCert: tls.cert, dist, home, userData };
+    const emergency = await startEmergencyServer(tls, EMERGENCY_PORT, () => emergencyMode);
+    harness = { app: null, caCert: tls.cert, dist, emergency, home, userData };
     await driveScenarios(harness);
 
     console.log(
@@ -219,6 +328,7 @@ async function main(): Promise<void> {
   } finally {
     await harness?.app?.close().catch(noop);
     harness?.dist.server.close();
+    harness?.emergency.server.close();
     rmSync(scratch, { recursive: true, force: true });
   }
 }

apps/desktop/e2e/config-canary/dist-server.mts

@@ -8,6 +8,7 @@ import type { PilotFixtureStep } from './fixture.mts';
 import {
   baseline,
   canary,
+  emergencyBytes,
   fixture,
   pointerBytes,
   rollback,
@@ -27,9 +28,16 @@ export type ServerMode =
   | 'tampered-pointer'
   | 'tampered-snapshot';
 
+export type EmergencyServerMode =
+  | 'equivocation'
+  | 'forced-minimum'
+  | 'kill-switch'
+  | 'offline'
+  | 'release';
+
 export interface DistRequest {
   readonly ifNoneMatch: string | null;
-  readonly mode: ServerMode;
+  readonly mode: EmergencyServerMode | ServerMode;
   readonly path: string;
   readonly status: 200 | 304 | 404 | 'disconnected';
 }
@@ -148,6 +156,55 @@ export function startDistServer(
   });
 }
 
+export function startEmergencyServer(
+  tls: { cert: string; key: string },
+  port: number,
+  getMode: () => EmergencyServerMode,
+): Promise<DistServer> {
+  const requests: DistRequest[] = [];
+  const server = createServer(
+    { cert: readFileSync(tls.cert), key: readFileSync(tls.key) },
+    (request, response) => {
+      const mode = getMode();
+      const path = new URL(request.url ?? '/', `https://127.0.0.1:${port}`).pathname;
+      const header = request.headers['if-none-match'];
+      const ifNoneMatch = typeof header === 'string' ? header : null;
+      if (mode === 'offline') {
+        requests.push({ ifNoneMatch, mode, path, status: 'disconnected' });
+        request.socket.destroy();
+        return;
+      }
+      if (path !== '/v1/acme/desktop/emergency.json') {
+        requests.push({ ifNoneMatch, mode, path, status: 404 });
+        response.writeHead(404).end();
+        return;
+      }
+      const name =
+        mode === 'kill-switch' ? 'killSwitch' : mode === 'forced-minimum' ? 'forcedMinimum' : mode;
+      const bytes = emergencyBytes(name);
+      const etag = `"emergency-${mode}"`;
+      if (ifNoneMatch === etag) {
+        requests.push({ ifNoneMatch, mode, path, status: 304 });
+        response.writeHead(304, { etag }).end();
+        return;
+      }
+      requests.push({ ifNoneMatch, mode, path, status: 200 });
+      response
+        .writeHead(200, {
+          'cache-control': 'public, max-age=60, must-revalidate',
+          'content-length': bytes.byteLength,
+          'content-type': 'application/json',
+          etag,
+        })
+        .end(bytes);
+    },
+  );
+  return new Promise((resolve, reject) => {
+    server.once('error', reject);
+    server.listen(port, '127.0.0.1', () => resolve({ requests, server }));
+  });
+}
+
 export function waitForRequest(
   server: DistServer,
   predicate: (request: DistRequest) => boolean,

apps/desktop/e2e/config-canary/electron-app.mts

@@ -5,13 +5,14 @@ import { join, resolve as resolvePath } from 'node:path';
 import type { ElectronApplication } from 'playwright-core';
 import { _electron } from 'playwright-core';
 
-import { fixture } from './fixture.mts';
+import { emergencyFixture, fixture } from './fixture.mts';
 
 const require = createRequire(import.meta.url);
 const desktopDir = resolvePath(import.meta.dirname, '../..');
 const electronBinary = require('electron') as unknown as string;
 
 export const PORT = 44100 + (process.pid % 1000);
+export const EMERGENCY_PORT = PORT + 1000;
 
 export function generateTlsMaterial(directory: string): { cert: string; key: string } {
   const key = join(directory, 'key.pem');
@@ -49,8 +50,8 @@ export function buildDesktopWithBootstrap(): void {
     brandId: fixture.target.brandId,
     channel: fixture.target.channel,
     defaults: fixture.bootstrapDefaults,
-    emergencyEndpoint: null,
-    emergencyPublicKeys: {},
+    emergencyEndpoint: `https://127.0.0.1:${EMERGENCY_PORT}`,
+    emergencyPublicKeys: emergencyFixture.keys.emergency,
     endpoint: `https://127.0.0.1:${PORT}`,
     maximumSchemaVersion: fixture.maximumSchemaVersion,
     publicKeys: fixture.keys,

apps/desktop/e2e/config-canary/fixture.mts

@@ -24,9 +24,28 @@ interface PilotFixture {
   readonly target: { brandId: string; channel: string; platform: string };
 }
 
+interface EmergencyFixture {
+  readonly documents: Readonly<
+    Record<
+      'equivocation' | 'forcedMinimum' | 'killSwitch' | 'release',
+      { readonly document: Readonly<Record<string, unknown>> }
+    >
+  >;
+  readonly keys: { readonly emergency: Readonly<Record<string, string>> };
+}
+
 export const fixture = JSON.parse(
   readFileSync(join(import.meta.dirname, '../fixtures/pilot-e2e-v1.json'), 'utf8'),
 ) as PilotFixture;
+export const emergencyFixture = JSON.parse(
+  readFileSync(
+    join(
+      import.meta.dirname,
+      '../../../../packages/foundation/common/src/config/__fixtures__/emergency-handoff-v1.json',
+    ),
+    'utf8',
+  ),
+) as EmergencyFixture;
 
 function fixtureStep(name: PilotFixtureStep['name']): PilotFixtureStep {
   const found = fixture.steps.find((step) => step.name === name);
@@ -45,6 +64,9 @@ export function pointerBytes(step: PilotFixtureStep): Buffer {
 export function snapshotBytes(step: PilotFixtureStep): Buffer {
   return Buffer.from(step.snapshotBase64Url, 'base64url');
 }
+export function emergencyBytes(name: keyof EmergencyFixture['documents']): Buffer {
+  return Buffer.from(JSON.stringify(emergencyFixture.documents[name].document), 'utf8');
+}
 
 // Same byte length keeps the JSON canonical while invalidating the Ed25519 signature.
 export const tamperedPointer = Buffer.from(

apps/desktop/e2e/config-canary/state-file.mts

@@ -4,6 +4,7 @@ import { join } from 'node:path';
 import { asyncRetry } from 'foxts/async-retry';
 
 const STORAGE_KEY = 'linkcode-config:v1:normal:acme:desktop:canary';
+const EMERGENCY_STORAGE_KEY = 'linkcode-config:v1:emergency:acme:desktop';
 
 export interface ConfigState {
   readonly highWater?: { readonly payloadSha256: string; readonly version: string };
@@ -17,19 +18,29 @@ export interface ConfigStateFile {
   readonly value: ConfigState;
 }
 
-function statePath(home: string): string {
+function statePath(home: string, storageKey: string): string {
   return join(
     home,
     '.config',
     'LinkCode Development',
     'config',
-    `${Buffer.from(STORAGE_KEY).toString('base64url')}.json`,
+    `${Buffer.from(storageKey).toString('base64url')}.json`,
   );
 }
 
 export async function readConfigState(home: string): Promise<ConfigStateFile | null> {
   try {
-    const raw = await readFile(statePath(home), 'utf8');
+    const raw = await readFile(statePath(home, STORAGE_KEY), 'utf8');
+    return { raw, value: JSON.parse(raw) as ConfigState };
+  } catch (error) {
+    if ((error as NodeJS.ErrnoException).code === 'ENOENT') return null;
+    throw error;
+  }
+}
+
+export async function readEmergencyState(home: string): Promise<ConfigStateFile | null> {
+  try {
+    const raw = await readFile(statePath(home, EMERGENCY_STORAGE_KEY), 'utf8');
     return { raw, value: JSON.parse(raw) as ConfigState };
   } catch (error) {
     if ((error as NodeJS.ErrnoException).code === 'ENOENT') return null;
@@ -58,5 +69,5 @@ export function waitForConfigState(
 }
 
 export function writeCorruptConfigState(home: string): Promise<void> {
-  return writeFile(statePath(home), '{"lkg":"corrupted', 'utf8');
+  return writeFile(statePath(home, STORAGE_KEY), '{"lkg":"corrupted', 'utf8');
 }