raise incompletedatabag exception if units empty

canonical · Jun 29, 2023 · 8d790a5 · 8d790a5
1 parent 248c87a
commit 8d790a5
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/src/relations/deprecated_shared_db_database_provides.py b/src/relations/deprecated_shared_db_database_provides.py
@@ -27,12 +27,14 @@ class _RemoteUnitDatabag(remote_databag.RemoteDatabag):
 
     def __init__(self, relation: ops.Relation) -> None:
         # Subordinate charms can only access principal unit's databag
+        self._app_name = relation.app.name
+        self._endpoint_name = relation.name
+        if not relation.units:
+            raise remote_databag.IncompleteDatabag(app_name=self._app_name, endpoint_name=self._endpoint_name)
         assert len(relation.units) == 1
         # Principal unit
         remote_unit = relation.units.copy().pop()
         dict.__init__(self, relation.data[remote_unit])
-        self._app_name = relation.app.name
-        self._endpoint_name = relation.name
 
 
 class _RelationBreaking(Exception):