Is vc-diff-mergebase broken on master?

[Matthias Meulien]

Hello,

I compiled from a clean Git repository with HEAD pointing to master
(a1887cc5e6) on both my personal computer and the one I use at work. And
vc-diff-mergebase is now unusable: Whatever I choose for the older and
the newer revisions, I get a "No changes between..." messages.

Am I missing something? I do lots of merge request review and use this
command on a daily basis, so I suspect a regression has been
introduced.

Am I the only one facing troubles with recent master and vc-git?
-- 
Matthias