In gitlab we have a dev branch and a main branch. All the dev work is done on separate independent individual branches and when peer review is done these branches are merged to dev branch. Every weekend we have a Production release cycle and during that time the dev branch is merged with Main using a MR. When I raise MR to merge dev branch to Main I get a message saying the source branch is x commits behind the target branch. Here the source branch is dev and target is Main. I am confused how can dev branch be x commits behind the Main branch since it can either be Ahead (because of new commits) or same as Main branch.