Automerge upstream branches

Description

Developers sometimes maintain multiple, parallel release branches and a fix merged in one release should automatically be merged into other, later releases. e.g. A fix applied to branch release-8.4 should automatically be applied to release-8.5 and release-8.6.

Proposal

1. Add UI to set optional upstream branch parameter for each branch.
2. Add UI to enable/disable automerge for each branch with an upstream branch specified.
3. For any merge request targeting a branch with an upstream branch:

• If the upstream branch has its own upstream branch, walk the chain to determine the entire list of upstream branches.
• Show notice that merging this MR will automerge the changes into the upstream branches.

1. When merge request is merged (via the web interface), attempt to cherry-pick the changes and apply to each upstream branch.
2. If the automerge fails for any upstream branch, create a new merge request for that specific branch with description back-referencing the original merge request.
3. [Stretch] Run CI on each automerge

Set Upstream	Branches	MR	New MR

Links