Bugfix
Detail
#28349
Migration processor for updating the role assignments fails with correct role assignments
The migration processor MoveRolesFromSingletonsToModules moves role assignments from singletons to the associated modules.
As it is a MigrationPostProcessor, it runs after all normal migrations and therefore also after migrations that may introduce new role assignments. If these are introduced correctly, i.e. from the module to the role, an error occurs.
Solution
If the source of the role assignment is a module, the processor should not do anything.
Test
No test.