fix: add full text search for neo4j db (MemTensor#1095)

* feat: add full_text_search for neo4j

* test: 改回去

---------

Co-authored-by: CaralHsi <caralhsi@gmail.com>

Author: hijzy

src/memos/graph_dbs/neo4j.py

@@ -928,6 +928,26 @@ def search_by_embedding(
 
         return records
 
+    def search_by_fulltext(
+        self,
+        query_words: list[str],
+        top_k: int = 10,
+        scope: str | None = None,
+        status: str | None = None,
+        threshold: float | None = None,
+        search_filter: dict | None = None,
+        user_name: str | None = None,
+        filter: dict | None = None,
+        knowledgebase_ids: list[str] | None = None,
+        tsquery_config: str | None = None,
+        **kwargs,
+    ) -> list[dict]:
+        """
+        TODO: 实现 Neo4j 的关键词检索, 以兼容 TreeTextMemory 的 keyword/fulltext 召回路径.
+        目前先返回空列表, 避免切换到 Neo4j 后因缺失方法导致运行时报错.
+        """
+        return []
+
     def get_by_metadata(
         self,
         filters: list[dict[str, Any]],

src/memos/graph_dbs/neo4j_community.py

@@ -382,6 +382,26 @@ def search_by_embedding(
 
         return filtered_results
 
+    def search_by_fulltext(
+        self,
+        query_words: list[str],
+        top_k: int = 10,
+        scope: str | None = None,
+        status: str | None = None,
+        threshold: float | None = None,
+        search_filter: dict | None = None,
+        user_name: str | None = None,
+        filter: dict | None = None,
+        knowledgebase_ids: list[str] | None = None,
+        tsquery_config: str | None = None,
+        **kwargs,
+    ) -> list[dict]:
+        """
+        TODO: 实现 Neo4j Community 的关键词检索, 以兼容 TreeTextMemory 的 keyword/fulltext 召回路径.
+        目前先返回空列表, 避免切换到 Neo4j 后因缺失方法导致运行时报错.
+        """
+        return []
+
     def _normalize_date_string(self, date_str: str) -> str:
         """
         Normalize date string to ISO 8601 format for Neo4j datetime() function.

src/memos/memories/textual/tree_text_memory/retrieve/searcher.py

@@ -511,16 +511,22 @@ def _retrieve_from_keyword(
 
         id_to_score: dict[str, float] = {}
         for scope in scopes:
-            hits = self.graph_store.search_by_fulltext(
-                query_words=tsquery_terms,
-                top_k=top_k * 2,
-                status="activated",
-                scope=scope,
-                search_filter=None,
-                filter=search_filter,
-                user_name=user_name,
-                tsquery_config="jiebaqry",
-            )
+            try:
+                hits = self.graph_store.search_by_fulltext(
+                    query_words=tsquery_terms,
+                    top_k=top_k * 2,
+                    status="activated",
+                    scope=scope,
+                    search_filter=None,
+                    filter=search_filter,
+                    user_name=user_name,
+                    tsquery_config="jiebaqry",
+                )
+            except Exception as e:
+                logger.warning(
+                    f"[PATH-KEYWORD] search_by_fulltext failed, scope={scope}, user_name={user_name}"
+                )
+                hits = []
             for h in hits or []:
                 hid = str(h.get("id") or "").strip().strip("'\"")
                 if not hid: