feat(05-09): PATCH /documents/{id} endpoint + cloud-aware Celery re-analyze

- Add DocumentPatch Pydantic model with filename and folder_id optional fields
- Add PATCH /api/documents/{doc_id} endpoint: ownership guard, model_fields_set
  to distinguish absent vs null folder_id, returns updated metadata dict
- Update _run() in document_tasks.py to use get_storage_backend_for_document
  for non-MinIO backends instead of hardcoded MinIO path
- CloudConnectionError caught in cloud path: returns extract_failed status
- Update test to use pure unit mocks (no PostgreSQL) for _run() cloud routing
- All 3 plan tests pass; 23 test_cloud.py tests pass

backend/api/documents.py

@@ -69,6 +69,19 @@ class UploadUrlRequest(BaseModel):
     content_type: str
 
 
+class DocumentPatch(BaseModel):
+    """Pydantic model for PATCH /api/documents/{doc_id}.
+
+    Optional fields — model_fields_set distinguishes "not provided" from "set to null".
+    At least one field must be present in model_fields_set (enforced in the handler).
+
+    T-05-09-01: explicit field declaration prevents mass assignment.
+    T-05-09-02: only filename and folder_id are accepted — no other fields can be set.
+    """
+    filename: Optional[str] = None
+    folder_id: Optional[uuid.UUID] = None
+
+
 # ── POST /api/documents/upload-url ───────────────────────────────────────────
 
 @router.post("/upload-url")
@@ -520,6 +533,53 @@ async def get_document(
     return meta
 
 
+# ── PATCH /api/documents/{doc_id} ────────────────────────────────────────────
+
+@router.patch("/{doc_id}")
+async def patch_document(
+    doc_id: str,
+    body: DocumentPatch,
+    session: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_regular_user),
+):
+    """Update document metadata (filename and/or folder_id).
+
+    T-05-09-01: get_regular_user dep rejects admins (403) and unauthenticated (401).
+    T-05-09-01: ownership check — non-owner gets 404 to avoid leaking document IDs (D-16).
+    T-05-09-02: response uses storage.get_metadata() which excludes credentials_enc and
+                password_hash via the _doc_to_dict whitelist.
+
+    At least one field must be provided — empty body returns 422.
+    folder_id=null moves the document to the root (no folder).
+    """
+    try:
+        uid = uuid.UUID(doc_id)
+    except ValueError:
+        raise HTTPException(404, "Document not found")
+
+    doc = await session.get(Document, uid)
+    if doc is None or doc.user_id != current_user.id:
+        raise HTTPException(404, "Document not found")
+
+    # Require at least one field to be set (model_fields_set tracks provided fields)
+    if not body.model_fields_set:
+        raise HTTPException(422, "At least one field (filename, folder_id) must be provided")
+
+    if "filename" in body.model_fields_set and body.filename is not None:
+        doc.filename = body.filename
+
+    if "folder_id" in body.model_fields_set:
+        # folder_id=null → move to root (no folder); folder_id=<uuid> → move to folder
+        doc.folder_id = body.folder_id
+
+    await session.commit()
+
+    meta = await storage.get_metadata(session, doc_id)
+    if meta is None:
+        raise HTTPException(404, "Document not found")
+    return meta
+
+
 # ── DELETE /api/documents/{doc_id} ───────────────────────────────────────────
 
 @router.delete("/{doc_id}")

backend/tasks/document_tasks.py

@@ -30,13 +30,17 @@ async def _run(document_id: str) -> dict:
 
     Opens its own AsyncSession (not shared with the upload request) to avoid
     cross-thread session contamination.
+
+    Cloud-aware: when doc.storage_backend != 'minio', uses
+    get_storage_backend_for_document() to retrieve bytes from the correct
+    cloud backend instead of hardcoding MinIO.
     """
     import uuid as _uuid
 
     from db.session import AsyncSessionLocal
     from db.models import Document
     from services import extractor, classifier
-    from storage import get_storage_backend
+    from storage import get_storage_backend, get_storage_backend_for_document
 
     async with AsyncSessionLocal() as session:
         # ── Step 1: fetch Document row ─────────────────────────────────────────
@@ -59,15 +63,39 @@ async def _run(document_id: str) -> dict:
         ai_provider = (user.ai_provider if user else None) or app_settings.default_ai_provider
         ai_model = (user.ai_model if user else None) or app_settings.default_ai_model
 
-        # ── Step 2: retrieve bytes from MinIO ──────────────────────────────────
+        # ── Step 2: retrieve bytes from the correct backend ────────────────────
+        # Cloud-aware: routes to cloud backend for non-MinIO documents (Plan 09).
+        # T-05-09-03: cloud credentials are loaded from DB inside this task's own
+        # session — no credentials travel through the Celery broker message.
         try:
+            if doc.storage_backend is None or doc.storage_backend == "minio":
                 backend = get_storage_backend()
                 file_bytes = await backend.get_object(doc.object_key)
+            else:
+                # Cloud path: user must be present (doc.user_id set at upload time)
+                if user is None:
+                    return {"document_id": document_id, "status": "missing_user"}
+
+                try:
+                    from storage.google_drive_backend import CloudConnectionError
+                except ImportError:
+                    class CloudConnectionError(Exception):  # type: ignore[no-redef]
+                        pass
+
+                try:
+                    backend = await get_storage_backend_for_document(doc, user, session)
+                    file_bytes = await backend.get_object(doc.object_key)
+                except CloudConnectionError:
+                    return {
+                        "document_id": document_id,
+                        "status": "extract_failed",
+                        "error": "cloud backend error",
+                    }
         except Exception as e:
             return {
                 "document_id": document_id,
                 "status": "extract_failed",
-                "error": f"MinIO retrieval failed: {e}",
+                "error": f"retrieval failed: {e}",
             }
 
         # ── Step 3: extract text from bytes ────────────────────────────────────

backend/tests/test_cloud.py

@@ -638,50 +638,76 @@ async def test_patch_document_wrong_owner(async_client, db_session):
     assert resp.status_code == 404
 
 
-async def test_reanalyze_cloud_document_routes_to_cloud_backend(db_session):
+async def test_reanalyze_cloud_document_routes_to_cloud_backend():
     """Re-analyze task calls get_storage_backend_for_document for cloud documents.
 
     Verifies that doc.storage_backend != 'minio' causes _run() to use the cloud
     backend path instead of the MinIO path (Plan 09, requirement CLOUD-07).
+
+    Pure unit test — mocks AsyncSessionLocal so no PostgreSQL connection is needed.
     """
-    from db.models import Document
     from tasks.document_tasks import _run
     from unittest.mock import AsyncMock, patch, MagicMock
 
-    auth = await _create_user_and_token(db_session, role="user")
-
-    # Create a nextcloud document
     doc_id = _uuid.uuid4()
-    doc = Document(
-        id=doc_id,
-        user_id=auth["user"].id,
-        filename="cloud.pdf",
-        content_type="application/pdf",
-        size_bytes=2048,
-        storage_backend="nextcloud",
-        status="uploaded",
-        object_key="nc_file_id_xyz",
-    )
-    db_session.add(doc)
-    await db_session.commit()
+    user_id = _uuid.uuid4()
 
-    # Mock cloud backend: returns file bytes, enabling extraction to proceed
+    # Build a minimal mock Document and User (no DB)
+    mock_doc = MagicMock()
+    mock_doc.id = doc_id
+    mock_doc.user_id = user_id
+    mock_doc.storage_backend = "nextcloud"
+    mock_doc.object_key = "nc_file_id_xyz"
+    mock_doc.content_type = "application/pdf"
+    mock_doc.filename = "cloud.pdf"
+    mock_doc.status = "uploaded"
+
+    mock_user = MagicMock()
+    mock_user.id = user_id
+    mock_user.ai_provider = None
+    mock_user.ai_model = None
+
+    # Mock cloud backend: returns fake bytes so extraction can proceed
     mock_cloud_backend = AsyncMock()
-    mock_cloud_backend.get_object = AsyncMock(return_value=b"%PDF-1.4 fake content")
+    mock_cloud_backend.get_object = AsyncMock(return_value=b"%PDF-1.4 fake")
 
     # Mock MinIO backend to verify it is NOT called
     mock_minio_backend = AsyncMock()
     mock_minio_backend.get_object = AsyncMock(return_value=b"should not be called")
 
-    with patch("tasks.document_tasks.get_storage_backend_for_document", return_value=mock_cloud_backend) as mock_gsb_doc, \
-         patch("tasks.document_tasks.get_storage_backend", return_value=mock_minio_backend) as mock_gsb:
+    # Mock the DB session returned by AsyncSessionLocal
+    mock_session = AsyncMock()
+
+    async def _fake_get(model, pk):
+        if model.__name__ == "Document":
+            return mock_doc
+        if model.__name__ == "User":
+            return mock_user
+        return None
+
+    mock_session.get = _fake_get
+
+    # AsyncSessionLocal is an async context manager; mock it
+    class _FakeSessionCM:
+        async def __aenter__(self):
+            return mock_session
+        async def __aexit__(self, *args):
+            pass
+
+    # Patch at the storage module level (source of the functions used via deferred import)
+    with patch("db.session.AsyncSessionLocal", return_value=_FakeSessionCM()), \
+         patch("storage.get_storage_backend_for_document", return_value=mock_cloud_backend), \
+         patch("storage.get_storage_backend", return_value=mock_minio_backend), \
+         patch("services.extractor.extract_text_from_bytes", return_value="extracted text"), \
+         patch("services.classifier.classify_document", return_value=["doc"]):
         result = await _run(str(doc_id))
 
-    # Cloud backend's get_object must have been called
+    # Cloud backend's get_object must have been called with the document's object_key
     mock_cloud_backend.get_object.assert_called_once_with("nc_file_id_xyz")
 
     # MinIO backend's get_object must NOT have been called
     mock_minio_backend.get_object.assert_not_called()
 
-    # Result must not be an error from MinIO path
-    assert result.get("status") != "extract_failed" or "MinIO" not in result.get("error", "")
+    # Result must reflect successful classification, not a MinIO error
+    assert result.get("status") in ("classified", "classification_failed"), \
+        f"Expected classified/classification_failed, got: {result}"