fix(P0): 修复取消链路断裂，前端取消后 GPU 仍继续推理 (#2009)

Co-authored-by: xiaoxia <dev@xiaoxiajianji.com>
Co-committed-by: xiaoxia <dev@xiaoxiajianji.com>

tests/unit/test_lipsync_gpu_integration.py

@@ -323,3 +323,126 @@ class TestGpuServiceHelpers:
         svc = GpuLipsyncService(db=fake_db)
         fake_db.query.return_value.filter.return_value.first.return_value = None
         assert svc.has_available_worker() is False
+
+
+# ── cancel_job 取消链路 (#2009) ─────────────────────────────────────
+
+
+def _build_sqlite_session():
+    from sqlalchemy import create_engine
+    from sqlalchemy.orm import sessionmaker
+
+    from packages.adapters.sqlalchemy_impl import models as _  # noqa: F401
+    from packages.adapters.sqlalchemy_impl.models import Base
+
+    engine = create_engine("sqlite:///:memory:", future=True)
+    Base.metadata.create_all(engine)
+    Session = sessionmaker(bind=engine, future=True)
+    return Session()
+
+
+def _make_real_job(db, *, status="processing", mediakit_task_id="gpu:gpu-task-1"):
+    import uuid
+
+    from packages.adapters.sqlalchemy_impl.models import LipsyncJobModel
+
+    job = LipsyncJobModel(
+        id=str(uuid.uuid4()),
+        user_id="u1",
+        project_id="p1",
+        video_url="videos/v.mp4",
+        audio_url="audios/a.wav",
+        enable_video_loop=True,
+        mediakit_task_id=mediakit_task_id,
+        status=status,
+    )
+    db.add(job)
+    db.commit()
+    return job
+
+
+def test_cancel_processing_gpu_job_marks_gpu_task_cancelled():
+    """processing 的 GPU job 取消时，关联 GpuLipsyncTask 必须同步置 cancelled."""
+    import uuid
+
+    from packages.adapters.sqlalchemy_impl.models import GpuLipsyncTaskModel
+
+    db = _build_sqlite_session()
+    gpu_task_id = str(uuid.uuid4())
+    gpu_task = GpuLipsyncTaskModel(
+        id=gpu_task_id,
+        video_url="v",
+        audio_url="a",
+        status="processing",
+        worker_id="w-1",
+        attempt=1,
+    )
+    db.add(gpu_task)
+    db.commit()
+
+    job = _make_real_job(db, mediakit_task_id=f"gpu:{gpu_task_id}")
+    from app.services.lipsync_service import LipsyncService
+
+    svc = LipsyncService(db=db, client=MagicMock())
+    result = svc.cancel_job(job.id, "u1")
+
+    assert result.status == "cancelled"
+    db.refresh(gpu_task)
+    assert gpu_task.status == "cancelled"
+    assert gpu_task.error_msg == "用户取消"
+    assert gpu_task.finished_at is not None
+
+
+def test_cancel_processing_gpu_job_skips_non_processing_gpu_task():
+    """GPU task 已不在 processing（如已 done）时，取消 job 不应改它，也不报错."""
+    import uuid
+
+    from packages.adapters.sqlalchemy_impl.models import GpuLipsyncTaskModel
+
+    db = _build_sqlite_session()
+    gpu_task_id = str(uuid.uuid4())
+    gpu_task = GpuLipsyncTaskModel(
+        id=gpu_task_id, video_url="v", audio_url="a", status="done", worker_id="w-1", attempt=1
+    )
+    db.add(gpu_task)
+    db.commit()
+
+    job = _make_real_job(db, mediakit_task_id=f"gpu:{gpu_task_id}")
+    from app.services.lipsync_service import LipsyncService
+
+    svc = LipsyncService(db=db, client=MagicMock())
+    result = svc.cancel_job(job.id, "u1")
+
+    assert result.status == "cancelled"
+    db.refresh(gpu_task)
+    assert gpu_task.status == "done"  # 没被动
+
+
+def test_cancel_processing_non_gpu_job_does_not_touch_gpu_table():
+    """mediakit_task_id 不是 gpu: 前缀（普通 MediaKit 任务）时，不查 GPU task."""
+    db = _build_sqlite_session()
+    job = _make_real_job(db, mediakit_task_id="mk-task-99")
+    from app.services.lipsync_service import LipsyncService
+
+    svc = LipsyncService(db=db, client=MagicMock())
+    result = svc.cancel_job(job.id, "u1")
+    assert result.status == "cancelled"
+
+
+def test_cancel_completed_job_unchanged():
+    """completed 状态不可取消，cancel_job 原样返回."""
+    db = _build_sqlite_session()
+    job = _make_real_job(db, status="completed", mediakit_task_id="gpu:x")
+    from app.services.lipsync_service import LipsyncService
+
+    svc = LipsyncService(db=db, client=MagicMock())
+    result = svc.cancel_job(job.id, "u1")
+    assert result.status == "completed"
+
+
+def test_cancel_job_not_found_returns_none():
+    db = _build_sqlite_session()
+    from app.services.lipsync_service import LipsyncService
+
+    svc = LipsyncService(db=db, client=MagicMock())
+    assert svc.cancel_job("nonexistent", "u1") is None