[MISC] Add missing connection vars (#920)

Author: sinclert-canonical

lib/charms/postgresql_k8s/v0/postgresql.py

@@ -35,7 +35,7 @@
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 48
+LIBPATCH = 49
 
 # Groups to distinguish HBA access
 ACCESS_GROUP_IDENTITY = "identity_access"
@@ -626,6 +626,7 @@ def list_access_groups(self) -> Set[str]:
         Returns:
             List of PostgreSQL database access groups.
         """
+        connection = None
         try:
             with self._connect_to_database() as connection, connection.cursor() as cursor:
                 cursor.execute(
@@ -646,6 +647,7 @@ def list_users(self) -> Set[str]:
         Returns:
             List of PostgreSQL database users.
         """
+        connection = None
         try:
             with self._connect_to_database() as connection, connection.cursor() as cursor:
                 cursor.execute("SELECT usename FROM pg_catalog.pg_user;")
@@ -664,6 +666,7 @@ def list_users_from_relation(self) -> Set[str]:
         Returns:
             List of PostgreSQL database users.
         """
+        connection = None
         try:
             with self._connect_to_database() as connection, connection.cursor() as cursor:
                 cursor.execute(