fix(vector_stores): return None from get() for missing IDs (milvus/weaviate/supabase) (#5562)

Co-authored-by: ly-wang19 <ly-wang19@users.noreply.github.com>

mem0/vector_stores/milvus.py

@@ -290,7 +290,7 @@ class MilvusDB(VectorStoreBase):
         schema = {"id": vector_id, "vectors": vector, "metadata": payload, "text": text}
         self.client.upsert(collection_name=self.collection_name, data=schema)
 
-    def get(self, vector_id):
+    def get(self, vector_id) -> Optional[OutputData]:
         """
         Retrieve a vector by ID.
 
@@ -298,9 +298,11 @@ class MilvusDB(VectorStoreBase):
             vector_id (str): ID of the vector to retrieve.
 
         Returns:
-            OutputData: Retrieved vector.
+            Optional[OutputData]: Retrieved vector, or None if the ID is not found.
         """
         result = self.client.get(collection_name=self.collection_name, ids=vector_id)
+        if not result:
+            return None
         output = OutputData(
             id=result[0].get("id", None),
             score=None,

mem0/vector_stores/supabase.py

@@ -176,7 +176,7 @@ class Supabase(VectorStoreBase):
         """
         result = self.collection.fetch([(vector_id,)])
         if not result:
-            return []
+            return None
 
         record = result[0]
         return OutputData(id=str(record.id), score=None, payload=record.metadata)

mem0/vector_stores/weaviate.py

@@ -305,7 +305,7 @@ class Weaviate(VectorStoreBase):
                 existing_payload: Mapping[str, str] = existing_data
                 collection.data.update(uuid=vector_id, properties=existing_payload, vector=vector)
 
-    def get(self, vector_id):
+    def get(self, vector_id) -> Optional[OutputData]:
         """
         Retrieve a vector by ID.
 
@@ -313,7 +313,7 @@ class Weaviate(VectorStoreBase):
             vector_id: ID of the vector to retrieve.
 
         Returns:
-            dict: Retrieved vector and metadata.
+            Optional[OutputData]: Retrieved vector, or None if the ID is not found.
         """
         vector_id = get_valid_uuid(vector_id)
         collection = self.client.collections.get(str(self.collection_name))
@@ -322,9 +322,8 @@ class Weaviate(VectorStoreBase):
             uuid=vector_id,
             return_properties=["hash", "created_at", "updated_at", "user_id", "agent_id", "run_id", "data", "category"],
         )
-        # results = {}
-        # print("reponse",response)
-        # for obj in response.objects:
+        if response is None:
+            return None
         payload = response.properties.copy()
         payload["id"] = str(response.uuid).split("'")[0]
         results = OutputData(