Change Merge Request target branch(es) depending on source branch

Problem to solve

In Git-flow model (see https://danielkummer.github.io/git-flow-cheatsheet/index.html), the target branch of a merge is not always the same:

• develop should be the target branch when the source branch prefix is feature/
• master should be the target branch when the source branch prefix is bugfix/, hotfix/ or release/

Now, developers need to manually select the target branch and it can be the wrong one.

Further details

gitlab-ce#33141 would also solve a related problem. A release, hotfix or bugfix branch should also be merged to develop. The possibility to have several target branches for a single Merge Request would be ideal.

Proposal

GitLab force the target branch(es) on the "New Merge Request" page depending on the source branch prefix (configurable in GitLab settings).