feat(desktop): preserve transcript continuity across bounded ranges

apps/desktop/e2e-budget.json

@@ -17,6 +17,10 @@
       "tests": 1,
       "electron": "renderer reload is the whole contract: an explicit new task must not reopen history"
     },
+    "partial-history-notice.spec.ts": {
+      "tests": 1,
+      "electron": "bounded paging crosses renderer, preload and Host transcript storage; the return-to-tail assertion also uses a real pointer hit-test"
+    },
     "proxy-password-editing.spec.ts": {
       "tests": 1,
       "electron": "the password never reaches the renderer; only the Host can report passwordConfigured and authenticate offline"

apps/desktop/e2e/fixtures.ts

@@ -523,6 +523,7 @@ type E2eTestFixtures = {
   parentRemovalWindow: Page;
   railRenderWindow: Page;
   promptRailWindow: Page;
+  partialHistoryWindow: Page;
   requestHeaderRowWindow: Page;
   newTaskTargetWindow: Page;
   directoryReferenceWindow: { page: Page; folder: string };
@@ -640,6 +641,17 @@ export const test = base.extend<E2eTestFixtures>({
       showWindow: true,
     }, use);
   },
+  // A transcript larger than the bounded Desktop range. Clicking an unloaded
+  // prompt exercises the real load-around path and its partial-history UI.
+  partialHistoryWindow: async ({}, use) => {
+    await withE2eWindow({
+      seed: false,
+      readinessSelector: '[data-turn-id]',
+      e2eFixtureScenario: 'chat-partial-history',
+      locale: 'zh-CN',
+      showWindow: true,
+    }, use);
+  },
   // Settings → 模型, where `no-models` is the seeded openai-compatible relay —
   // the connection type whose detail page owns the custom request headers
   // editor. Shown, because what this window is for is a rendered box

apps/desktop/e2e/partial-history-notice.spec.ts

@@ -0,0 +1,84 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { expect, test } from './fixtures';
+
+const GAP = '.maka-transcript-gap-row';
+const TURN = '.maka-transcript-turn';
+
+test('bounded transcript ranges expose only their truthful boundary gaps', async ({
+  partialHistoryWindow: page,
+}) => {
+  await page.setViewportSize({ width: 1_400, height: 800 });
+
+  const olderGap = page.locator('[data-transcript-gap="older"]');
+  const newerGap = page.locator('[data-transcript-gap="newer"]');
+  await expect(olderGap).toBeVisible();
+  await expect(olderGap.getByRole('button', {
+    name: /^(?:加载较早消息|Load earlier messages)$/,
+  })).toBeVisible();
+  await expect(newerGap).toHaveCount(0);
+  await expect(page.locator('.maka-transcript-history-controls')).toHaveCount(0);
+
+  const oldestPrompt = page.locator(
+    '.maka-prompt-rail-tick[data-prompt-turn-id="turn-partial-history-1"]',
+  );
+  await expect(oldestPrompt).toBeVisible();
+  await oldestPrompt.click();
+
+  const firstTurn = page.locator('[data-turn-id="turn-partial-history-1"]');
+  await expect(firstTurn).toBeVisible();
+  await expect(firstTurn).toHaveAttribute('data-search-highlight', 'true');
+  await expect(olderGap).toHaveCount(0);
+  await expect(newerGap).toBeVisible();
+  await expect(newerGap.getByRole('button', {
+    name: /^(?:加载较新消息|Load newer messages)$/,
+  })).toBeVisible();
+  await expect(page.locator(GAP)).toHaveCount(1);
+  expect(await page.locator(TURN).count()).toBeLessThanOrEqual(10);
+
+  const loadNewer = newerGap.getByRole('button', {
+    name: /^(?:加载较新消息|Load newer messages)$/,
+  });
+  await loadNewer.click();
+  await expect(page.locator('[data-turn-id="turn-partial-history-2"]')).toBeVisible();
+  await expect(olderGap).toHaveCount(0);
+  await expect(newerGap).toBeVisible();
+  await expect(loadNewer).toBeEnabled();
+
+  await loadNewer.click();
+  await expect(page.locator('[data-turn-id="turn-partial-history-3"]')).toBeVisible();
+  await expect(olderGap).toBeVisible();
+  await expect(newerGap).toBeVisible();
+  await expect(loadNewer).toBeEnabled();
+  await expect(oldestPrompt).toBeVisible();
+  await expect(page.locator(GAP)).toHaveCount(2);
+  expect(await page.locator(TURN).count()).toBeLessThanOrEqual(10);
+
+  const returnToLatest = page.getByRole('button', {
+    name: /^(?:滚动主对话到底部|Scroll main conversation to bottom)$/,
+  });
+  await expect(returnToLatest).toBeVisible();
+  await returnToLatest.click();
+
+  await expect(page.locator('[data-turn-id="turn-partial-history-18"]')).toBeVisible();
+  await expect(newerGap).toHaveCount(0);
+  await expect(oldestPrompt).toBeVisible();
+  expect(await page.locator(TURN).count()).toBeLessThanOrEqual(10);
+});

apps/desktop/e2e/transcript-scroll-cost.spec.ts

@@ -165,7 +165,7 @@ async function moveToTail(page: Page): Promise<void> {
  */
 async function returnToLatest(page: Page): Promise<void> {
   const returnLatest = page.getByRole('button', {
-    name: /^(?:返回最新消息|Return to latest)$/,
+    name: /^(?:滚动主对话到底部|Scroll main conversation to bottom)$/,
   });
   await expect(returnLatest).toBeVisible();
   await returnLatest.click();

apps/desktop/renderer-architecture.json

@@ -893,7 +893,7 @@
           "react": 1
         },
         "importSpecifiers": 121,
-        "nonTriviaTokens": 15007
+        "nonTriviaTokens": 14996
       },
       "src/renderer/use-app-shell-composer-quotes.ts": {
         "importDeclarations": 2,
@@ -1157,7 +1157,6 @@
         "actionFactories": [],
         "dependencyPaths": {
           "./chat-recovery-notice": 1,
-          "./locales/conversation-copy": 1,
           "./locales/shell-copy": 1,
           "./onboarding-hero": 1,
           "./use-app-shell-session-ui-reads": 1,

apps/desktop/src/main/__tests__/app-shell-session-ui-state.test.ts

@@ -34,6 +34,7 @@ import {
 import {
   transcriptReadingPosition,
   type TranscriptHistoryGates,
+  type TranscriptHistoryPending,
 } from '../../renderer/features/conversation/index.js';
 
 function boundaryRequest(requestId: string): SandboxBoundaryRequestEvent {
@@ -102,19 +103,26 @@ function deferredHistoryController() {
 }
 
 function crossSessionGateScenario() {
+  type HistoryRequest = Parameters<typeof transcriptReadingPosition.loadHistory>[0]['request'];
   const gates: TranscriptHistoryGates = new WeakMap();
+  const sessionIds = { a: 'session', b: 'session:a' } as const;
   const sides = {
     a: deferredHistoryController(),
     b: deferredHistoryController(),
   };
   let active: 'a' | 'b' = 'a';
   let range: object = sides.a.controller;
-  const pending = { a: [] as boolean[], b: [] as boolean[] };
+  let currentPending: TranscriptHistoryPending | undefined;
+  const pending = {
+    a: [] as Array<Pick<HistoryRequest, 'target'> | undefined>,
+    b: [] as Array<Pick<HistoryRequest, 'target'> | undefined>,
+  };
   const errors = { a: [] as unknown[], b: [] as unknown[] };
   return {
     sides,
     pending,
     errors,
+    currentPending: () => currentPending,
     switchTo(id: 'a' | 'b') {
       active = id;
       range = sides[id].controller;
@@ -126,11 +134,17 @@ function crossSessionGateScenario() {
       const side = sides[id];
       return transcriptReadingPosition.loadHistory({
         gates,
+        sessionId: sessionIds[id],
         request,
         controller: side.controller,
         maxBytes: 4096,
         isCurrent: () => active === id && range === side.controller,
-        setPending: (value) => pending[id].push(value),
+        setPending: (update) => {
+          currentPending = update(currentPending);
+          pending[id].push(currentPending?.sessionId === sessionIds[id]
+            ? { target: currentPending.target }
+            : undefined);
+        },
         onError: (error) => errors[id].push(error),
       });
     },
@@ -524,18 +538,19 @@ describe('app shell session UI state controller', () => {
     const stale = scenario.load('a', { target: 'earlier' });
     await new Promise<void>((resolve) => setImmediate(resolve));
     assert.deepEqual(scenario.sides.a.calls, ['before']);
-    assert.deepEqual(scenario.pending.a, [true]);
+    assert.deepEqual(scenario.pending.a, [{ target: 'earlier' }]);
 
     scenario.switchTo('b');
     const navigation = scenario.load('b', { target: 'latest' });
     await new Promise<void>((resolve) => setImmediate(resolve));
     assert.deepEqual(scenario.sides.b.calls, ['latest']);
-    assert.deepEqual(scenario.pending.b, [true]);
+    assert.deepEqual(scenario.pending.b, [{ target: 'latest' }]);
 
-    scenario.sides.b.settleLatest();
     scenario.sides.a.settleBefore();
-    await navigation;
     await stale;
+    assert.deepEqual(scenario.currentPending(), { sessionId: 'session:a', target: 'latest' });
+    scenario.sides.b.settleLatest();
+    await navigation;
   });
 
   it('leaves the switched-to Session untouched when a stale Session load settles late', async () => {
@@ -546,13 +561,13 @@ describe('app shell session UI state controller', () => {
     const navigation = scenario.load('b', { target: 'latest' });
     scenario.sides.b.settleLatest();
     await navigation;
-    assert.deepEqual(scenario.pending.b, [true, false]);
+    assert.deepEqual(scenario.pending.b, [{ target: 'latest' }, undefined]);
     assert.deepEqual(scenario.sides.b.calls, ['latest']);
 
     scenario.sides.a.settleBefore();
     await stale;
     await new Promise<void>((resolve) => setImmediate(resolve));
-    assert.deepEqual(scenario.pending.b, [true, false]);
+    assert.deepEqual(scenario.pending.b, [{ target: 'latest' }, undefined]);
     assert.deepEqual(scenario.sides.b.calls, ['latest']);
     assert.deepEqual(scenario.errors.b, []);
   });
@@ -565,7 +580,7 @@ describe('app shell session UI state controller', () => {
     scenario.sides.a.failBefore(new Error('earlier read failed'));
     await stale;
     assert.deepEqual(scenario.errors.a, []);
-    assert.deepEqual(scenario.pending.a, [true, false]);
+    assert.deepEqual(scenario.pending.a, [{ target: 'earlier' }, undefined]);
     assert.deepEqual(scenario.pending.b, []);
   });
 
@@ -582,7 +597,12 @@ describe('app shell session UI state controller', () => {
     assert.deepEqual(scenario.sides.a.calls, ['before', 'latest']);
     scenario.sides.a.settleLatest();
     await Promise.allSettled([queuedEarlier, queuedLatest]);
-    assert.deepEqual(scenario.pending.a, [true, false, true, false]);
+    assert.deepEqual(scenario.pending.a, [
+      { target: 'earlier' },
+      undefined,
+      { target: 'latest' },
+      undefined,
+    ]);
   });
 
   it('replays a queued forward load with its reading anchor after a backward load settles', async () => {
@@ -596,7 +616,12 @@ describe('app shell session UI state controller', () => {
     assert.deepEqual(scenario.sides.a.calls, ['before', 'after:4096:turn-anchor']);
     scenario.sides.a.settleAfter();
     await queued;
-    assert.deepEqual(scenario.pending.a, [true, false, true, false]);
+    assert.deepEqual(scenario.pending.a, [
+      { target: 'earlier' },
+      undefined,
+      { target: 'later' },
+      undefined,
+    ]);
   });
 
   it('keeps the queued latest load when adjacent requests arrive after it', async () => {
@@ -613,7 +638,12 @@ describe('app shell session UI state controller', () => {
     assert.deepEqual(scenario.sides.a.calls, ['before', 'latest']);
     scenario.sides.a.settleLatest();
     await Promise.allSettled([queuedLatest, queuedEarlier, queuedLater]);
-    assert.deepEqual(scenario.pending.a, [true, false, true, false]);
+    assert.deepEqual(scenario.pending.a, [
+      { target: 'earlier' },
+      undefined,
+      { target: 'latest' },
+      undefined,
+    ]);
   });
 
   it('does not replay a settled load after its Session range was replaced', async () => {
@@ -627,7 +657,7 @@ describe('app shell session UI state controller', () => {
     await new Promise<void>((resolve) => setImmediate(resolve));
     assert.deepEqual(scenario.sides.a.calls, ['before']);
     assert.deepEqual(scenario.sides.b.calls, []);
-    assert.deepEqual(scenario.pending.a, [true, false]);
+    assert.deepEqual(scenario.pending.a, [{ target: 'earlier' }, undefined]);
     scenario.sides.a.settleLatest();
     await queued;
   });
@@ -642,7 +672,12 @@ describe('app shell session UI state controller', () => {
     assert.deepEqual(scenario.sides.a.calls, ['before', 'latest']);
     scenario.sides.a.settleLatest();
     await queued;
-    assert.deepEqual(scenario.pending.a, [true, false, true, false]);
+    assert.deepEqual(scenario.pending.a, [
+      { target: 'earlier' },
+      undefined,
+      { target: 'latest' },
+      undefined,
+    ]);
     assert.deepEqual(scenario.pending.b, []);
     assert.deepEqual(scenario.sides.b.calls, []);
   });

apps/desktop/src/main/e2e-fixture.ts

@@ -35,11 +35,14 @@ import {
   LONG_SIDEBAR_PROJECT_ID,
   LONG_SIDEBAR_PROJECT_NAME,
   LONG_SIDEBAR_SESSION_PREFIX,
+  PARTIAL_HISTORY_SESSION_ID,
   PROMPT_RAIL_SESSION_ID,
   TURN_SESSION_ID,
   writeSession,
 } from './e2e-fixture/seed-helpers.js';
 import {
+  partialHistoryMessages,
+  partialHistorySession,
   promptRailMessages,
   promptRailSession,
   turnMessages,
@@ -60,6 +63,7 @@ const E2E_FIXTURE_SCENARIOS = new Set<E2eFixtureScenario>([
   'turn-narrative',
   'turn-narrative-browser',
   'chat-prompt-rail',
+  'chat-partial-history',
   'settings-data',
   'settings-bots-onboarding',
   'settings-general',
@@ -169,6 +173,8 @@ export function getE2eFixtureState(fixture: E2eFixture | null): E2eFixtureState
       // Workbar collapsed: the rail lives on the chat scrollport's right edge,
       // and the panel would take the width the measurements are about.
       return { ...state, activeSessionId: PROMPT_RAIL_SESSION_ID, workbarCollapsed: true };
+    case 'chat-partial-history':
+      return { ...state, activeSessionId: PARTIAL_HISTORY_SESSION_ID, workbarCollapsed: true };
     case 'settings-data':
       return { ...state, activeSessionId: TURN_SESSION_ID, openSettingsSection: 'data' };
     case 'settings-bots-onboarding':
@@ -224,6 +230,13 @@ export async function seedE2eFixture(input: {
   if (scenario === 'chat-prompt-rail') {
     await writeSession(input.workspaceRoot, promptRailSession(now), promptRailMessages(now));
   }
+  if (scenario === 'chat-partial-history') {
+    await writeSession(
+      input.workspaceRoot,
+      partialHistorySession(now),
+      partialHistoryMessages(now),
+    );
+  }
   if (scenario === 'sidebar-search-modal-open') {
     for (const seed of longSidebarSessions(now)) {
       await writeSession(input.workspaceRoot, seed.header, seed.messages);