test(desktop): cover Side Chat retention across linked sessions

apps/desktop/e2e-budget.json

@@ -46,8 +46,8 @@
       "electron": "SQLite admission crosses preload and main, survives both renderer reload and complete Electron restart, and cached history must render when the live IPC endpoint is unavailable"
     },
     "session-workbar.spec.ts": {
-      "tests": 5,
-      "electron": "Git changes re-read on native window focus; native PTY ownership survives Session navigation and renderer replacement, while Stop/exit cross preload/main into the terminal view; Side Chat owns a Host fork lifecycle; first send reaches the Host; the composer usage entry opens a workbar whose per-Session visibility survives renderer reload."
+      "tests": 6,
+      "electron": "Git changes re-read on native window focus; native PTY ownership survives Session navigation and renderer replacement, while Stop/exit cross preload/main into the terminal view; Side Chat owns a Host fork lifecycle across linked Session navigation and preserves its unsent draft while the Host fork stays live; first send reaches the Host; the composer usage entry opens a workbar whose per-Session visibility survives renderer reload."
     },
     "settings.spec.ts": {
       "tests": 2,

apps/desktop/e2e/fixtures.ts

@@ -122,7 +122,7 @@ export async function waitForInvocableSkills(
  * backend (BackendRegistry override in main); this only satisfies the UI
  * readiness gates. Kept in the fixture so test data stays out of production main.
  */
-async function seedE2eConnection(userDataDir: string): Promise<void> {
+async function seedE2eConnection(userDataDir: string): Promise<string> {
   const workspaceRoot = path.join(userDataDir, 'workspaces', 'default');
   const capability = await resolveStorageRoot({ path: workspaceRoot, kind: 'interactive' });
   const owner = await tryAcquireInteractiveRootOwner(capability);
@@ -179,6 +179,7 @@ async function seedE2eConnection(userDataDir: string): Promise<void> {
     if (defaultTarget.kind !== 'committed') {
       throw new Error(`E2E default target seed was not committed: ${defaultTarget.kind}`);
     }
+    return connection.connectionId;
   } finally {
     await owner.close();
   }
@@ -213,12 +214,14 @@ async function seedRailRenderSessions(userDataDir: string): Promise<void> {
   }
 }
 
-async function seedParentRemovalSessions(userDataDir: string): Promise<void> {
+async function seedParentRemovalSessions(userDataDir: string, llmConnectionId: string): Promise<void> {
+  await mkdir(path.join(userDataDir, 'project'), { recursive: true });
   const workspaceRoot = path.join(userDataDir, 'workspaces', 'default');
   const store = createSessionStore(workspaceRoot);
   try {
     const parent = await store.create({
       cwd: path.join(userDataDir, 'project'),
+      llmConnectionId,
       llmConnectionSlug: 'e2e',
       model: 'claude-sonnet-4-5-20250929',
       permissionMode: 'ask',
@@ -227,6 +230,7 @@ async function seedParentRemovalSessions(userDataDir: string): Promise<void> {
     });
     await store.createSubagent({
       cwd: path.join(userDataDir, 'project'),
+      llmConnectionId,
       llmConnectionSlug: 'e2e',
       model: 'claude-sonnet-4-5-20250929',
       permissionMode: 'ask',
@@ -435,8 +439,11 @@ export async function withE2eWindow(
   const mainLogs: string[] = [];
   const rendererLogs: string[] = [];
   try {
-    if (seed) await seedE2eConnection(userDataDir);
-    if (parentRemovalSessions) await seedParentRemovalSessions(userDataDir);
+    const llmConnectionId = seed ? await seedE2eConnection(userDataDir) : undefined;
+    if (parentRemovalSessions) {
+      if (!llmConnectionId) throw new Error('Parent removal fixture requires a seeded connection');
+      await seedParentRemovalSessions(userDataDir, llmConnectionId);
+    }
     if (railRenderSessions) await seedRailRenderSessions(userDataDir);
     if (invocableSkills) await seedE2eInvocableSkills(userDataDir);
     if (gitReviewExtraFiles !== undefined) {

apps/desktop/e2e/session-workbar.spec.ts

@@ -17,7 +17,15 @@
  * under the License.
  */
 
-import { awaitSendReady, COMPOSER_INPUT, test, expect } from './fixtures';
+import {
+  awaitSendReady,
+  COMPOSER_INPUT,
+  ensureSidebarExpanded,
+  PARENT_REMOVAL_CHILD_NAME,
+  PARENT_REMOVAL_PARENT_NAME,
+  test,
+  expect,
+} from './fixtures';
 import { FAKE_HOLD_OPEN_PROMPT } from '@maka/runtime/test-only/fake-backend';
 import type { Page } from '@playwright/test';
 import { writeFile } from 'node:fs/promises';
@@ -345,3 +353,52 @@ test('Side Chat survives collapse and source switches, then cleans up on explici
     )
     .toBe(false);
 });
+
+test('linked child navigation keeps the Side Chat Host fork and draft', async ({
+  parentRemovalWindow: page,
+}) => {
+  const sessions = await page.evaluate(() => window.maka.sessions.list());
+  const parent = sessions.find((session) => session.name === PARENT_REMOVAL_PARENT_NAME);
+  const child = sessions.find((session) => session.name === PARENT_REMOVAL_CHILD_NAME);
+  expect(parent).toBeDefined();
+  expect(child).toBeDefined();
+  const knownSessionIds = new Set(sessions.map((session) => session.id));
+  await ensureSidebarExpanded(page);
+  const sidebar = page.getByRole('navigation', { name: '任务列表' });
+  await sidebar.locator(`[data-session-id=${JSON.stringify(parent!.id)}]`).click();
+  await page.getByRole('button', { name: '展开任务工作栏' }).click();
+  await page.getByRole('button', {
+    name: /侧边对话.*在不打断主任务的情况下追问和只读探索/,
+  }).click();
+
+  const companion = page.locator('.maka-quote-companion');
+  const draft = companion.locator(COMPOSER_INPUT);
+  await draft.fill('retain this reply across linked navigation');
+  await draft.press('Enter');
+  await expect(companion).toContainText('Fake backend received: retain this reply across linked navigation');
+  let forkId: string | undefined;
+  await expect.poll(async () => {
+    forkId = (await page.evaluate(() => window.maka.sessions.list()))
+      .find((session) => !knownSessionIds.has(session.id))?.id;
+    return forkId;
+  }).not.toBeUndefined();
+  await draft.fill('unsent linked draft');
+
+  await page.getByRole('button', { name: '搜索任务', exact: true }).click();
+  const search = page.locator('[data-maka-contract="search-modal"]');
+  await search.locator('input').fill(PARENT_REMOVAL_CHILD_NAME);
+  await search.locator('.maka-search-modal-result-title', {
+    hasText: PARENT_REMOVAL_CHILD_NAME,
+  }).click();
+  await expect(page.getByRole('region', { name: `对话：${PARENT_REMOVAL_CHILD_NAME}` })).toBeVisible();
+  await expect(companion).toBeAttached();
+  await expect(companion).not.toBeVisible();
+  await expect(draft).toHaveText('unsent linked draft');
+  await expect.poll(async () => (await page.evaluate(() => window.maka.sessions.list()))
+    .some((session) => session.id === forkId)).toBe(true);
+
+  await sidebar.locator(`[data-session-id=${JSON.stringify(parent!.id)}]`).click();
+  await expect(companion).toBeVisible();
+  await expect(draft).toHaveText('unsent linked draft');
+  await expect(companion).toContainText('Fake backend received: retain this reply across linked navigation');
+});