branch heads: fix regression introduced in
e67e5b60e55f (
issue1726)
For merge nodes it is not adequate to only check a single possible
branch head for whether it is an ancestor of the latest head, but it
needs to be done for each possible branch head.
adding a
tree a0c8bcbbb45c
parent 000000000000
author test 0 0
committer test 0 0
revision 0
branch default
adda