fix: 完善失败重试与跳过边界

docs/MVP-WorkOrders.md

@@ -470,6 +470,27 @@ test: 记录双平台默认规模真实验收
 fix: 完善失败重试与跳过边界
 ```
 
+完成记录：
+
+```text
+完成日期：2026-07-03
+相关 commit：fix: 完善失败重试与跳过边界
+验证命令：
+- .venv/bin/python -m pytest tests/integration/test_failure_tolerance.py tests/unit/test_report_stats.py tests/integration/test_task_creation.py tests/unit/test_comment_pagination.py tests/unit/test_ai_schema.py -q
+- .venv/bin/python -m pytest tests/unit tests/integration -q
+- .venv/bin/python -m pytest tests/unit tests/integration --cov=app --cov-branch --cov-report=term-missing
+- curl -f http://localhost:8000/health
+验收结论：
+- 连续 429 超限测试覆盖并断言退避序列 1s→2s→4s，错误类型为 rate_limited 且不泄露 API Key。
+- 单个内容条目评论抓取失败时记录 failed item，后续内容继续处理，任务可成功。
+- 所有内容条目失败时任务 status=failed，error_stage/error_type/error_message 可见。
+- AI 全批失败已有测试覆盖：评论标记 failed，任务 analysis_status=insufficient。
+- 报告摘要失败时 item/hotspot 报告仍创建，并使用默认总结文案。
+- 已有 running 任务时拒绝新建任务，返回 400。
+- 未发现 httpx.AsyncClient 使用。
+遗留问题：W04 发现的 SQLite WAL/SHM deleted 句柄问题转入 WO-06。
+```
+
 ### WO-06 SQLite 数据库稳定性与恢复策略
 
 优先级：P0

tests/integration/test_failure_tolerance.py

@@ -34,6 +34,24 @@ class OneFailedOneSuccessfulItemPlatform:
         return [CommentData(source_comment_id="c1", content="继续成功")]
 
 
+class AllItemsFailPlatform:
+    def fetch_hotspots(self, *, limit):
+        from app.platforms.base import HotspotData
+
+        return [HotspotData(source_hot_id="h1", title="热点一", rank=1)]
+
+    def search_items_by_hotspot(self, keyword, *, limit):
+        from app.platforms.base import ContentItemData
+
+        return [
+            ContentItemData(source_item_id="bad-one", item_type="video", title="失败内容一"),
+            ContentItemData(source_item_id="bad-two", item_type="video", title="失败内容二"),
+        ]
+
+    def fetch_comments(self, source_item_id, *, limit):
+        raise PlatformAPIError("comments exhausted", error_type="rate_limited", status_code=429)
+
+
 def test_hotspot_failure_marks_task_failed(monkeypatch):
     with make_test_client() as (_client, engine):
         monkeypatch.setattr("app.services.task_service.build_platform", lambda _platform: FailingHotspotPlatform())
@@ -102,3 +120,30 @@ def test_failed_content_item_is_recorded_and_following_item_continues(monkeypatc
         assert failed_item.error_stage == "crawl_comments"
         assert failed_item.error_type == "rate_limited"
         assert successful_item.status == "success"
+
+
+def test_task_fails_with_visible_reason_when_all_content_items_fail(monkeypatch):
+    with make_test_client() as (_client, engine):
+        monkeypatch.setattr("app.services.task_service.build_platform", lambda _platform: AllItemsFailPlatform())
+
+        with Session(engine) as session:
+            task = create_task(
+                session,
+                CreateTaskRequest(platform="douyin", hotspot_limit=1, item_limit_per_hotspot=2, comment_limit_per_item=10),
+                submit_background=False,
+            )
+            task_id = task.id
+            run_task(task_id, session_factory=lambda: session)
+
+            persisted = session.get(Task, task_id)
+            failed_items = session.query(ContentItem).filter_by(task_id=task_id, status="failed").all()
+
+        assert persisted.status == "failed"
+        assert persisted.total_items_count == 2
+        assert persisted.processed_items_count == 2
+        assert persisted.successful_items_count == 0
+        assert persisted.failed_items_count == 2
+        assert persisted.error_stage == "crawl_comments"
+        assert persisted.error_type == "rate_limited"
+        assert persisted.error_message == "comments exhausted"
+        assert len(failed_items) == 2

tests/unit/test_report_stats.py

@@ -5,7 +5,7 @@ from sqlalchemy.orm import Session
 
 from app.db import Base
 from app.models import Comment, ContentItem, Hotspot, Task
-from app.services.report_service import build_comment_metrics, generate_item_report
+from app.services.report_service import DEFAULT_SUMMARY, build_comment_metrics, generate_hotspot_report, generate_item_report
 
 
 def test_build_comment_metrics_counts_sentiments_and_top_labels():
@@ -74,3 +74,55 @@ def test_generate_item_report_persists_markdown_and_default_summary():
             assert "样本评论数量" in report.markdown_content
     finally:
         engine.dispose()
+
+
+def test_generate_hotspot_report_persists_default_summary_when_ai_summary_fails():
+    engine = create_engine("sqlite:///:memory:", connect_args={"check_same_thread": False})
+    Base.metadata.create_all(engine)
+    try:
+        with Session(engine) as session:
+            task = Task(platform="xiaohongshu", status="success")
+            session.add(task)
+            session.flush()
+            hotspot = Hotspot(task_id=task.id, platform="xiaohongshu", title="热点", raw_data="{}")
+            session.add(hotspot)
+            session.flush()
+            item = ContentItem(
+                task_id=task.id,
+                hotspot_id=hotspot.id,
+                platform="xiaohongshu",
+                source_item_id="n1",
+                item_type="note",
+                title="笔记",
+                status="success",
+                raw_data="{}",
+            )
+            session.add(item)
+            session.flush()
+            session.add(
+                Comment(
+                    task_id=task.id,
+                    hotspot_id=hotspot.id,
+                    content_item_id=item.id,
+                    platform="xiaohongshu",
+                    source_comment_id="c1",
+                    content="好评",
+                    sentiment="positive",
+                    labels='["认可"]',
+                    raw_data="{}",
+                )
+            )
+            session.commit()
+
+            report = generate_hotspot_report(
+                session,
+                hotspot.id,
+                summary_provider=lambda *_args, **_kwargs: (_ for _ in ()).throw(RuntimeError("summary failed")),
+            )
+
+            assert report.report_type == "hotspot"
+            assert report.hotspot_id == hotspot.id
+            assert report.summary == DEFAULT_SUMMARY
+            assert DEFAULT_SUMMARY in report.markdown_content
+    finally:
+        engine.dispose()