Vladimir Shushlin authored Aug 07, 2023 and Mehmet Emin INAC committed Aug 07, 2023

In https://gitlab.com/gitlab-org/gitlab/-/merge_requests/126539
we introduced the validation on
allow_descendants_override_disabled_shared_runners
to always be false if shared runners are enabled.

It's guarded by

```ruby
changes.has_key?(:allow_descendants_override_disabled_shared_runners)
```

but it can break the creation of new groups
https://gitlab.com/gitlab-org/gitlab/blob/49d501d4/app/services/groups/create_service.rb#L105-105
because it can copy invalid configuration from the parent group:

```ruby
@group.shared_runners_enabled = @group.parent.shared_runners_enabled
@group.allow_descendants_override_disabled_shared_runners = @group.parent.allow_descendants_override_disabled_shared_runners
```

This MR fixes the invalid combination of
1. `shared_runners_enabled = TRUE` AND
2. `allow_descendants_override_disabled_shared_runners = TRUE`

This combination doesn't make sense: we always allow to disable shared runners
on the descendants.

Changelog: fixed