Misleading message on fast forward merges

Description

It is possible to configure a project to do a fast-forward only merge for accepting merge requests. However, if gitlab is unable to execute a rebase by itself, it shows this error:

The language "To merge this request, first rebase locally" seems like just one of two ways to do it. A developer could merge instead of rebasing locally. For example:

git pull origin master
git push

This would work equally well at ensuring a fast-forward merge could then happen. With the language the way it is, the developer is potentially lead down a workflow they may not normally use. Language such as "To merge this request, first merge, or rebase locally" would be more accurate. (Though a bit open to interpretation)

Links

Related #895 #17741 (closed)