fix(harmonyos): honor jump to bottom while history loads

src/apps/mobile/harmonyos/AGENTS.md

@@ -90,6 +90,14 @@ fake RPC: send must clear the input before pressing **Acknowledge**, and a
 **Next draft** entered while pending must survive acknowledgment. Exercise both
 compact and wide layouts and return to normal `EntryAbility` afterward.
 
+For history loading and explicit jump-to-bottom navigation, install the debug
+HAP and run `python3 tools/check-history-scroll.py --hdc "$HDC"`. The
+`history-scroll` preview holds a mock history response while the production
+ChatTimeline handles the jump. It covers success/failure at wide and compact
+content widths with a live resize and restores the normal App afterward.
+This is native controller UI coverage, not remote transport or physical fold
+coverage; exercise those separately when their behavior changes.
+
 For durable transcript projection, run
 `node --test tools/tests/session-record.test.cjs tools/tests/host-stream.test.cjs tools/tests/streaming-markdown.test.cjs`.
 The `durable-timeline` native preview uses the

src/apps/mobile/harmonyos/entry/src/main/ets/entryability/EntryAbility.ets

@@ -13,7 +13,7 @@ export default class EntryAbility extends UIAbility {
 
   onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void {
     const scenarioId = want.parameters?.['openbitfunDesignPreview'];
-    if (scenarioId === 'durable-timeline' || scenarioId === 'composer-submit' || scenarioId === 'catalog-refresh' || scenarioId === 'catalog-refresh-dark' || scenarioId === 'device-selector' || scenarioId === 'device-selector-dark' || scenarioId === 'welcome-home' || scenarioId === 'connected-conversation' ||
+    if (scenarioId === 'history-scroll' || scenarioId === 'durable-timeline' || scenarioId === 'composer-submit' || scenarioId === 'catalog-refresh' || scenarioId === 'catalog-refresh-dark' || scenarioId === 'device-selector' || scenarioId === 'device-selector-dark' || scenarioId === 'welcome-home' || scenarioId === 'connected-conversation' ||
       scenarioId === 'streaming-dark' ||
       scenarioId === 'reconnecting-wide' || scenarioId === 'narrow-multiline' ||
       scenarioId === 'fold-context' || scenarioId === 'long-reading' ||

src/apps/mobile/harmonyos/entry/src/main/ets/pages/components/ChatTimeline.ets

@@ -352,6 +352,7 @@ export struct ChatTimeline {
       // Keep short transcripts at the content start. Active turns and explicit
       // follow-to-bottom calls still place streaming content at the tail.
       .stackFromEnd(false)
+      .id('chat-timeline-list')
       // Keeps the read position when older messages are prepended above.
       .maintainVisibleContentPosition(false)
       .edgeEffect(EdgeEffect.Spring, { alwaysEnabled: true })
@@ -394,6 +395,7 @@ export struct ChatTimeline {
             .fontSize(18)
             .fontColor([INK])
         }
+        .id('chat-timeline-jump')
         .width(42)
         .height(42)
         .backgroundColor(CARD)
@@ -574,7 +576,14 @@ export struct ChatTimeline {
   }
 
   private requestFollowToBottom(reason: string): void {
-    if (this.historyRestoreKey || this.historyLoading || !this.stickToBottom || this.followTimerId !== 0) {
+    // Explicit navigation supersedes a pending history-position restoration.
+    // Jump now even if the host response is still pending; ordinary revisions
+    // resume tail following when historyLoading clears, including on failure.
+    if (reason === 'jump-button') {
+      this.cancelHistoryAnchor();
+    }
+    if (this.historyRestoreKey || (this.historyLoading && reason !== 'jump-button') ||
+      !this.stickToBottom || this.followTimerId !== 0) {
       return;
     }
     this.followTimerId = setTimeout(() => {

src/apps/mobile/harmonyos/entry/src/main/ets/pages/preview/HistoryScrollPreview.ets

@@ -0,0 +1,59 @@
+import { ObservableChatTimelineItem } from '../../model/ChatTimelineModels';
+import { ChatTimeline } from '../components/ChatTimeline';
+import { INK, PAGE_BG } from '../components/Theme';
+
+/** Hold a history response while exercising the production list's jump button. */
+@ComponentV2
+export struct HistoryScrollPreview {
+  @Local rows: ObservableChatTimelineItem[] = [];
+  @Local revision: number = 0;
+  @Local loading: boolean = false;
+  @Local failed: boolean = false;
+  @Local compact: boolean = false;
+  private page: number = 0;
+
+  aboutToAppear(): void {
+    this.rows = this.pageRows(0);
+  }
+
+  private pageRows(page: number): ObservableChatTimelineItem[] {
+    const rows: ObservableChatTimelineItem[] = [];
+    for (let index = 0; index < 20; index++) {
+      const id = `page-${page}-row-${index}`;
+      rows.push(new ObservableChatTimelineItem({
+        id, type: 'user_message', isStreaming: false, isFinalizing: false,
+        message: { id, role: 'user', text: `History probe ${id}`, status: 'completed', timestamp: `${index}` }
+      }));
+    }
+    return rows;
+  }
+
+  private finish(failed: boolean): void {
+    if (!this.loading) return;
+    if (!failed) {
+      this.page--;
+      this.rows = this.pageRows(this.page).concat(this.rows);
+      this.revision++;
+    }
+    this.failed = failed;
+    this.loading = false;
+  }
+
+  build() {
+    Column({ space: 8 }) {
+      Row({ space: 8 }) {
+        Button('Complete').id('history-complete').onClick(() => { this.finish(false); })
+        Button('Fail').id('history-fail').onClick(() => { this.finish(true); })
+        Button('Resize').id('history-resize').onClick(() => { this.compact = !this.compact; })
+      }
+      Text(`loading=${this.loading} failed=${this.failed} compact=${this.compact}`)
+        .id('history-state').fontColor(INK)
+      ChatTimeline({
+        timelineItems: this.rows, timelineRevision: this.revision,
+        hasMoreMessages: true, historyLoading: this.loading, historyFailed: this.failed,
+        maxContentWidth: this.compact ? 360 : 0,
+        onLoadOlder: () => { this.failed = false; this.loading = true; }
+      })
+    }.width('100%').height('100%').backgroundColor(PAGE_BG)
+  }
+}

src/apps/mobile/harmonyos/entry/src/main/ets/pages/preview/MobileDesignGallery.ets

@@ -1,3 +1,4 @@
+import { HistoryScrollPreview } from './HistoryScrollPreview';
 import { ComposerSubmissionPreview } from './ComposerSubmissionPreview';
 import { DurableTimelinePreview } from './DurableTimelinePreview';
 import { DeviceSelectorPreview } from './DeviceSelectorPreview';
@@ -36,7 +37,9 @@ struct MobileDesignGallery {
   }
 
   build() {
-    if (AppStorage.get<string>('scenarioId') === 'durable-timeline') {
+    if (AppStorage.get<string>('scenarioId') === 'history-scroll') {
+      HistoryScrollPreview()
+    } else if (AppStorage.get<string>('scenarioId') === 'durable-timeline') {
       DurableTimelinePreview()
     } else if (AppStorage.get<string>('scenarioId') === 'composer-submit') {
       ComposerSubmissionPreview()

src/apps/mobile/harmonyos/tools/check-history-scroll.py

@@ -0,0 +1,97 @@
+#!/usr/bin/env python3
+"""Check history/jump interaction using native rows and a held mock response.
+
+Install the debug HAP first. Runs compact/wide widths and a live resize, then
+returns to the normal app without changing account or remote session data.
+"""
+import argparse
+import json
+import os
+from pathlib import Path
+import re
+import subprocess
+import tempfile
+import time
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('--hdc', default=os.environ.get('HDC', 'hdc'))
+    parser.add_argument('--device')
+    parser.add_argument('--expect-bug', action='store_true')
+    args = parser.parse_args()
+    command = [args.hdc] + (['-t', args.device] if args.device else [])
+    output = Path(tempfile.mkdtemp(prefix='openbitfun-history-scroll-'))
+    print(f'Evidence: {output}', flush=True)
+    contract = (Path(__file__).resolve().parent.parent /
+                'entry/src/main/ets/services/HarmonyUpgradeIdentityContract.ets')
+    bundle = re.search(r"APP_BUNDLE:\s*string\s*=\s*'([^']+)'", contract.read_text()).group(1)
+
+    def run(*parts):
+        return subprocess.check_output(command + list(parts), text=True, timeout=30)
+
+    def start(preview=False):
+        run('shell', 'aa', 'force-stop', bundle)
+        params = ['shell', 'aa', 'start', '-a', 'EntryAbility', '-b', bundle]
+        if preview:
+            params += ['--ps', 'openbitfunDesignPreview', 'history-scroll']
+        run(*params)
+        time.sleep(1)
+
+    def layout(label):
+        remote = run('shell', 'uitest', 'dumpLayout').strip().split('saved to:')[-1]
+        local = output / f'{label}.json'
+        run('file', 'recv', remote, str(local))
+        nodes = []
+
+        def walk(node):
+            nodes.append(node.get('attributes', {}))
+            for child in node.get('children', []):
+                walk(child)
+
+        walk(json.loads(local.read_text()))
+        return nodes
+
+    def click(nodes, field, value):
+        node = next(n for n in nodes if n.get(field) == value)
+        left, top, right, bottom = map(int, re.findall(r'-?\d+', node['bounds']))
+        run('shell', 'uitest', 'uiInput', 'click', str((left + right) // 2), str((top + bottom) // 2))
+        time.sleep(0.3)
+
+    def capture(label):
+        remote = f'/data/local/tmp/{label}.jpeg'
+        run('shell', 'snapshot_display', '-f', remote)
+        run('file', 'recv', remote, str(output / f'{label}.jpeg'))
+
+    try:
+        for compact in [False, True]:
+            for failure in [False, True]:
+                label = f'{"compact" if compact else "wide"}-{"failure" if failure else "success"}'
+                start(True)
+                nodes = layout(f'{label}-initial')
+                if compact:
+                    click(nodes, 'id', 'history-resize')
+                    nodes = layout(f'{label}-resized')
+                # The fixture opens at the start, exposing the real paging entry.
+                header = next(n for n in nodes if n.get('text') in ['加载更早消息', 'Load older messages'])
+                click(nodes, 'text', header['text'])
+                nodes = layout(f'{label}-loading')
+                assert any('loading=true' in n.get('text', '') for n in nodes)
+                click(nodes, 'id', 'chat-timeline-jump')
+                nodes = layout(f'{label}-jump')
+                click(nodes, 'id', 'history-fail' if failure else 'history-complete')
+                time.sleep(1)
+                nodes = layout(f'{label}-settled')
+                tail = any(n.get('text') == 'History probe page-0-row-19' for n in nodes)
+                jump = any(n.get('id') == 'chat-timeline-jump' for n in nodes)
+                capture(label)
+                print(f'{label}: tail_visible={tail} jump_visible={jump}', flush=True)
+                assert tail != args.expect_bug, f'{label}: unexpected tail visibility'
+                if not args.expect_bug:
+                    assert not jump, f'{label}: jump should hide at the tail'
+    finally:
+        start()
+
+
+if __name__ == '__main__':
+    main()

src/apps/mobile/harmonyos/tools/tests/host-stream.test.cjs

@@ -6,7 +6,9 @@ const ts = require('typescript');
 const source = fs.readFileSync(path.join(__dirname, '../../entry/src/main/ets/services/HostSessionStream.ets'), 'utf8');
 const compiled = ts.transpileModule(source, { compilerOptions: { target: ts.ScriptTarget.ES2022, module: ts.ModuleKind.CommonJS } }).outputText;
 const exportsObject = {};
-new Function('require', 'exports', compiled)(() => ({}), exportsObject);
+new Function('require', 'exports', compiled)(name =>
+  name.endsWith('RemoteLogger') ? { RemoteLogger: { info() {}, warn() {}, error() {} } } : {},
+  exportsObject);
 const { HostSessionStream, parseHostStreamHint, checkHostStreamPage, HostStreamUnsupportedError, HOST_STREAM_CHANGED_EVENT } = exportsObject;
 
 async function settle(predicate, label = 'stream did not settle') {