Fix: shared dataset chunk index lookup (#14764)

### What problem does this PR solve?

shared dataset chunk index lookup

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

test/testcases/test_http_api/test_file_management_within_dataset/test_doc_sdk_routes_unit.py

@@ -706,6 +706,36 @@ class TestDocRoutesUnit:
         assert res["data"]["total"] == 1
         assert res["data"]["chunks"][0]["id"] == "chunk-1"
 
+    def test_list_chunks_uses_dataset_owner_index_for_team_dataset(self, monkeypatch):
+        module = _load_restful_chunk_module(monkeypatch)
+        seen = {}
+        monkeypatch.setattr(module.KnowledgebaseService, "accessible", lambda **_kwargs: True)
+        monkeypatch.setattr(
+            module.KnowledgebaseService,
+            "get_by_id",
+            lambda _dataset_id: (True, SimpleNamespace(tenant_id="owner-tenant")),
+        )
+        monkeypatch.setattr(module.DocumentService, "query", lambda **_kwargs: [_DummyDoc(kb_id="ds-1")])
+        monkeypatch.setattr(module, "request", SimpleNamespace(args=_DummyArgs({})))
+
+        def _index_exist(index_name, dataset_id):
+            seen["index_exist"] = (index_name, dataset_id)
+            return True
+
+        class _Retriever:
+            async def search(self, _query, index_name, dataset_ids, *_args, **_kwargs):
+                seen["search"] = (index_name, dataset_ids)
+                return SimpleNamespace(total=0, ids=[], field={}, highlight={})
+
+        _patch_docstore(monkeypatch, module, index_exist=_index_exist)
+        monkeypatch.setattr(module.settings, "retriever", _Retriever())
+
+        res = _run(_route_core(module.list_chunks)("member-tenant", "ds-1", "doc-1"))
+
+        assert res["code"] == 0
+        assert seen["index_exist"] == ("idx-owner-tenant", "ds-1")
+        assert seen["search"] == ("idx-owner-tenant", ["ds-1"])
+
     def test_add_chunk_access_guard(self, monkeypatch):
         module = _load_restful_chunk_module(monkeypatch)
         monkeypatch.setattr(module.KnowledgebaseService, "accessible", lambda **_kwargs: False)

test/testcases/test_web_api/test_chunk_app/test_chunk_routes_unit.py

@@ -377,7 +377,7 @@ def _load_chunk_module(monkeypatch):
 
         @staticmethod
         def get_by_id(_kb_id):
-            return True, SimpleNamespace(pagerank=0.6, tenant_embd_id=2, tenant_llm_id=1)
+            return True, SimpleNamespace(pagerank=0.6, tenant_id="tenant-1", tenant_embd_id=2, tenant_llm_id=1)
 
     kb_service_mod.KnowledgebaseService = _KnowledgebaseService
     monkeypatch.setitem(sys.modules, "api.db.services.knowledgebase_service", kb_service_mod)
@@ -653,4 +653,3 @@ def test_restful_chunk_guard_branches_unit(monkeypatch):
     res = _run(_route_core(module.switch_chunks)("tenant-1", "kb-1", "doc-1"))
     assert res["message"] == "`available_int` or `available` is required.", res
 
-