Adding a compatibility mode to ease migration usages

src/snowflake/snowpark/session.py

@@ -329,6 +329,8 @@ class Session:
 
     class RuntimeConfig:
         def __init__(self, session: "Session", conf: Dict[str, Any]) -> None:
+            self.compatibility_mode = False
+            self.__props_dict = {}
             self._session = session
             self._conf = {
                 "use_constant_subquery_alias": True,
@@ -345,7 +347,7 @@ def get(self, key: str, default=None) -> Any:
                     return getattr(self._session, key)
                 if hasattr(self._session._conn._conn, key):
                     return getattr(self._session._conn._conn, key)
-                return self._conf.get(key, default)
+                return self._conf.get(key, default) or self.__props_dict.get(key, default)
 
         def is_mutable(self, key: str) -> bool:
             with self._lock:
@@ -369,9 +371,12 @@ def set(self, key: str, value: Any) -> None:
                     if key in self._conf:
                         self._conf[key] = value
                 else:
-                    raise AttributeError(
-                        f'Configuration "{key}" does not exist or is not mutable in runtime'
-                    )
+                    if self.compatibility_mode:
+                        self.__props_dict[key] = value
+                    else:
+                        raise AttributeError(
+                            f'Configuration "{key}" does not exist or is not mutable in runtime'
+                        )
 
     class SessionBuilder:
         """

tests/integ/test_session.py

@@ -74,6 +74,10 @@ def test_runtime_config(db_parameters):
         in err.value.args[0]
     )
 
+    # test conf with compatibility_mode=True
+    session.conf.set("property1", "value1")
+    assert session.conf.get("property1") == "value1"
+
     session.close()