Introduced in GitLab Enterprise Edition 7.13.
If you want to make sure every merge request is approved by one or more people, you can enforce this workflow by using merge request approvals. Merge request approvals allow you to set the number of necessary approvals and predefine a list of approvers that will need to approve every merge request in a project.
You can configure the approvals in the project settings, under merge requests. To enable it, set Approvals required to 1 or higher and search for the users you want to be approvers.
This sets the amount of approvals required before being able to merge a merge request. At 0, this disables the feature. Any value above 0 requires that amount of different users to approve the merge request.
The number of approvers can be higher than the required approvals.
With this setting turned on, approvals are reset when a new push is done to the merge request branch.
Turn Reset approvals on push off if you want approvals to persist, independent of changes to the merge request.
Approvals do not get reset when rebasing a merge request from the UI.
If one of the approvers pushes a commit to the branch that is tied to the merge request, they automatically get excluded from the approvers list.
At the approvers area you can define the default set of users that need to approve a merge request.
Depending on the number of required approvals and the number of approvers set, there are different cases:
Note that approvers and the number of required approvals can be changed while creating or editing a merge request.
When someone is marked as a required approver for a merge request, an email is sent to them and a todo is added to their list of todos.
Introduced in GitLab Enterprise Edition 8.13.
You can also define one or more groups that can be assigned as approvers. It works the same way like regular approvers do, the only difference is that you assign several users with one action. One possible scenario would be to to assign a group of approvers at the project level and change them later when creating or editing the merge request.
A designated approver can remove their approval at any time. If, when an approver removes their approval, the number of approvals given falls below the number of required approvals, the merge request cannot be accepted.
If, on the other hand, an approver removes their approval but the number of approvals given stays at or above the number of required approvals, the merge request can still be accepted.
After configuring approvals, you will be able to change the default set of approvers and the amount of required approvals before creating the merge request. The amount of required approvals, if changed, must be greater than the default set at the project level. This ensures that you're not forced to adjust settings when someone is unavailable for approval, yet the process is still enforced.
If the approvers are changed via the project's settings after a merge request is created, the merge request retains the previous approvers, but you can always change them by editing the merge request.
The author of a merge request cannot be set as an approver for that merge request.
To approve a merge request, simply press the Approve merge request button.
Once you approve, the button will disappear and the number of approvers will be decreased by one.
To remove approval, just press the Remove your approval button