fix: separate session opening logic from instantiation

ensures correctness of self.session.open call in Connection

Signed-off-by: varun-edachali-dbx <varun.edachali@databricks.com>

Author: varun-edachali-dbx

src/databricks/sql/client.py

@@ -243,6 +243,7 @@ def read(self) -> Optional[OAuthToken]:
             _use_arrow_native_complex_types,
             **kwargs,
         )
+        self.session.open()
 
         logger.info(
             "Successfully opened connection with session "
@@ -343,9 +344,7 @@ def get_protocol_version(openSessionResp):
     @property
     def open(self) -> bool:
         """Return whether the connection is open by checking if the session is open."""
-        # NOTE: we have to check for the existence of session in case the __del__ is called
-        # before the session is instantiated
-        return hasattr(self, "session") and self.session.open
+        return self.session.is_open
 
     def cursor(
         self,

src/databricks/sql/session.py

@@ -31,10 +31,14 @@ def __init__(
 
         This class handles all session-related behavior and communication with the backend.
         """
-        self.open = False
+        self.is_open = False
         self.host = server_hostname
         self.port = kwargs.get("_port", 443)
 
+        self.session_configuration = session_configuration
+        self.catalog = catalog
+        self.schema = schema
+
         auth_provider = get_python_sql_connector_auth_provider(
             server_hostname, **kwargs
         )
@@ -151,4 +155,4 @@ def close(self) -> None:
         except Exception as e:
             logger.error(f"Attempt to close session raised a local exception: {e}")
 
-        self.open = False
+        self.is_open = False