Cannot change tracking branch if two branches point to the same hash

[queil]

In one of my subrepos I've branched test2 off of master. Neither of them has any new commits so they effectively point to the same hash.

> git subrepo status
1 subrepo:

Git subrepo 'myrepo':
  Subrepo Branch:  subrepo/myrepo
  Remote URL:      [email protected]:zzz/xxx.git
  Upstream Ref:    66e98f3
  Tracking Branch: test2
  Pulled Commit:   66e98f3
  Pull Parent:     7e41165

When I try changing the tracking branch to master I get:

git subrepo pull -b master --force --update myrepo
Subrepo 'myrepo' pulled from '[email protected]:zzz/xxx.git' (master).

But git subrepo status still shows:

1 subrepo:

Git subrepo 'myrepo':
  Subrepo Branch:  subrepo/myrepo
  Remote URL:      [email protected]:zzz/xxx.git
  Upstream Ref:    66e98f3
  Tracking Branch: test2
  Pulled Commit:   66e98f3
  Pull Parent:     7e41165

Expected result

> git subrepo status
1 subrepo:

Git subrepo 'myrepo':
  Subrepo Branch:  subrepo/myrepo
  Remote URL:     [email protected]:zzz/xxx.git
  Upstream Ref:    66e98f3
  Tracking Branch: master
  Pulled Commit:   66e98f3
  Pull Parent:     c7c19cd

Workaround

Change the tracking branch to some other branch (that points to another commit) first and then change it again to the target one.

[Eoxan]

Can confirm that I am also running into this issue