fix: restore rag chat permission feedback

fastapi_modules/fastapi_leaudit/services/impl/ragDatasetServiceImpl.py

@@ -1,3 +1,5 @@
+"""RAG 知识库服务实现。"""
+
 from __future__ import annotations
 
 import asyncio
@@ -42,6 +44,8 @@ from fastapi_modules.fastapi_leaudit.services.impl.tenantResolver import TenantR
 
 
 class RagDatasetServiceImpl(IRagDatasetService):
+    """RAG 知识库服务实现。"""
+
     _ACTIVE_INDEXING_STATUSES = {"waiting", "parsing", "cleaning", "splitting", "indexing"}
     _DELETABLE_DOCUMENT_STATUSES = {"completed", "error", "paused"}
     _APP_LINK_SQL = """
@@ -295,7 +299,32 @@ class RagDatasetServiceImpl(IRagDatasetService):
             if target_is_default:
                 await self._clear_default_flags(session, tenant_code=resolved_tenant_code)
             elif existing.get("is_default") and Body.get("is_default") is False:
-                raise LeauditException(StatusCodeEnum.HTTP_400_BAD_REQUEST, "默认知识库不能直接取消，请先将其他知识库设为默认")
+                normalized_tenant_code = str(resolved_tenant_code or "").strip()
+                default_filters = [
+                    "deleted_at IS NULL",
+                    "is_default = TRUE",
+                    "id <> :dataset_id",
+                ]
+                default_params = {"dataset_id": DatasetId}
+                if normalized_tenant_code:
+                    default_filters.append("tenant_code = :tenant_code")
+                    default_params["tenant_code"] = normalized_tenant_code
+                else:
+                    default_filters.append("(tenant_code IS NULL OR BTRIM(tenant_code) = '')")
+                other_default_count = (
+                    await session.execute(
+                        text(
+                            f"""
+                            SELECT COUNT(1)
+                            FROM rag_dataset
+                            WHERE {" AND ".join(default_filters)}
+                            """
+                        ),
+                        default_params,
+                    )
+                ).scalar_one()
+                if int(other_default_count or 0) <= 0:
+                    raise LeauditException(StatusCodeEnum.HTTP_400_BAD_REQUEST, "默认知识库不能直接取消，请先将其他知识库设为默认")
             await session.execute(
                 text(
                     """