Fix pgvector sslmode handling for PostgreSQL URIs (#5308)

tests/vector_stores/test_pgvector.py

@@ -4,7 +4,7 @@ import unittest
 import uuid
 from unittest.mock import MagicMock, patch
 
-from mem0.vector_stores.pgvector import PGVector, _build_filter_conditions
+from mem0.vector_stores.pgvector import PGVector, _build_filter_conditions, _with_sslmode
 
 
 class TestPGVector(unittest.TestCase):
@@ -2084,8 +2084,8 @@ class TestPGVector(unittest.TestCase):
             connection_string=connection_string
         )
         
-        # Verify ConnectionPool was called with the connection string including sslmode
-        expected_conn_string = f"{connection_string} sslmode=require"
+        # Verify ConnectionPool was called with sslmode as a URI query parameter
+        expected_conn_string = f"{connection_string}?sslmode=require"
         mock_connection_pool.assert_called_with(
             conninfo=expected_conn_string,
             min_size=1,
@@ -2095,6 +2095,36 @@ class TestPGVector(unittest.TestCase):
         self.assertEqual(pgvector.collection_name, "test_collection")
         self.assertEqual(pgvector.embedding_model_dims, 3)
 
+    def test_with_sslmode_appends_uri_query_param(self):
+        """Test sslmode is appended to URI connection strings without corrupting dbname."""
+        connection_string = _with_sslmode(
+            "postgresql://user:pass@localhost:5432/db?connect_timeout=10",
+            "require",
+        )
+
+        self.assertEqual(
+            connection_string,
+            "postgresql://user:pass@localhost:5432/db?connect_timeout=10&sslmode=require",
+        )
+
+    def test_with_sslmode_replaces_existing_uri_sslmode(self):
+        """Test existing URI sslmode values are replaced rather than duplicated."""
+        connection_string = _with_sslmode(
+            "postgresql://user:pass@localhost:5432/db?sslmode=prefer&connect_timeout=10",
+            "require",
+        )
+
+        self.assertEqual(
+            connection_string,
+            "postgresql://user:pass@localhost:5432/db?connect_timeout=10&sslmode=require",
+        )
+
+    def test_with_sslmode_preserves_keyword_conninfo_format(self):
+        """Test non-URI conninfo strings keep PostgreSQL keyword syntax."""
+        connection_string = _with_sslmode("dbname=test user=postgres sslmode=prefer", "require")
+
+        self.assertEqual(connection_string, "dbname=test user=postgres sslmode=require")
+
     # Enhanced Test for Index Creation with DiskANN
     @patch('mem0.vector_stores.pgvector.PSYCOPG_VERSION', 3)
     @patch('mem0.vector_stores.pgvector.ConnectionPool')