Introduced in GitLab Premium 12.8.
Merge request approval rules prevent users from overriding certain settings on the project level. When enabled at the instance level, these settings are no longer editable on the project level.
To enable merge request approval rules for an instance:
- On the top bar, select Menu > Admin.
- On the left sidebar, select Push Rules, and expand Merge request (MR) approvals.
- Set the required rule.
- Click Save changes.
Merge request approval rules that can be set at an instance level are:
- Prevent approval by author. Prevents project maintainers from allowing request authors to merge their own merge requests.
- Prevent approvals by users who add commits. Prevents project maintainers from allowing users to approve merge requests if they have submitted any commits to the source branch.
- Prevent editing approval rules in projects and merge requests. Prevents users from modifying the approvers list in project settings or in individual merge requests.
Also read the project level merge request approval rules, which are affected by instance level rules.