Fix _base_connection_cfg mutation bug

Signed-off-by: Mynhardt Burger <Mynhardt.Burger@ibm.com>

caikit_tgis_backend/tgis_backend.py

@@ -14,6 +14,7 @@
 """This module implements a TGIS backend configuration"""
 
 # Standard
+from copy import deepcopy
 from threading import Lock
 from typing import Any, Dict, Optional
 
@@ -197,10 +198,10 @@ def register_model_connection(
         # Craft new connection config
         new_conn_cfg = {}
         if conn_cfg is None:
-            new_conn_cfg = self._base_connection_cfg
+            new_conn_cfg = deepcopy(self._base_connection_cfg)
         else:
             if fill_with_defaults:
-                new_conn_cfg = self._base_connection_cfg
+                new_conn_cfg = deepcopy(self._base_connection_cfg)
             new_conn_cfg.update(conn_cfg)
 
         # Create model connection

tests/test_tgis_backend.py

@@ -16,6 +16,7 @@
 """
 
 # Standard
+from copy import deepcopy
 from dataclasses import asdict
 from typing import Any, Dict, Optional
 from unittest import mock
@@ -736,6 +737,7 @@ def test_tgis_backend_register_model_connection(
     # Assert new model is not in backend
     assert model_id not in tgis_be._remote_models_cfg
     assert model_id not in tgis_be._model_connections
+    backup_base_cfg = deepcopy(tgis_be._base_connection_cfg)
 
     # Register model
     tgis_be.register_model_connection(model_id, conn_cfg, fill_with_defaults=fill)
@@ -765,6 +767,9 @@ def test_tgis_backend_register_model_connection(
         if v is not None
     } == expected_conn_cfg
 
+    # Confirm that the source _base_connection_cfg wasn't mutated
+    assert tgis_be._base_connection_cfg == backup_base_cfg
+
 
 ## Failure Tests ###############################################################