grant roles after installing demo data

pum/pum_config.py

@@ -231,7 +231,7 @@ def role_manager(self) -> RoleManager:
         """Return a RoleManager instance based on the roles defined in the configuration."""
         if not self.config.roles:
             logger.warning("No roles defined in the configuration. Returning an empty RoleManager.")
-            return RoleManager()
+            return RoleManager([])
         return RoleManager([role.model_dump() for role in self.config.roles])
 
     def pre_hook_handlers(self) -> list[HookHandler]:

pum/upgrader.py

@@ -133,13 +133,15 @@ def install_demo_data(
         name: str,
         *,
         parameters: dict | None = None,
+        grant: bool = True,
     ) -> None:
         """Install demo data for the module.
 
         Args:
             connection: The database connection to use.
             name: The name of the demo data to install.
             parameters: The parameters to pass to the demo data SQL.
+            grant: If True, grant permissions to the roles after installing the demo data. Default is True.
         """
         if name not in self.config.demo_data():
             raise PumException(f"Demo data '{name}' not found in the configuration.")
@@ -167,4 +169,9 @@ def install_demo_data(
 
         connection.commit()
 
+        if grant:
+            self.config.role_manager().grant_permissions(connection=connection, commit=False)
+
+        connection.commit()
+
         logger.info("Demo data '%s' installed successfully.", name)