get the original branch of ref branch

问题

I'm trying to watch for changes on branches that have merge requests on them and then checkout them.

Scenario:

1. developer creates branchX

2. developer creates merge request MergeRequest1 in gitlab for branchX

3. developer pushes to branchX

4. team city watched +:refs/(merge-requests/*)/head and detects a change

Actual: team city checks out refs/merge-requests/1/head to local merge-requests/1

What I'm trying to achieve: team city checks out refs/merge-requests/1/head to local branchX

How do I get branchX?

来源：https://stackoverflow.com/questions/51962509/get-the-original-branch-of-ref-branch