How to handle a merge problem

[Pete Brunet]

I just did the following:
sh ./get_source.sh

and got this:
<snip>
# cd ./jdk && hg pull -u
pulling from http://hg.openjdk.java.net/jdk8/jdk8//jdk
searching for changes
adding changesets
adding manifests
adding file changes
added 563 changesets with 3123 changes to 2661 files (+1 heads)
not updating: crosses branches (merge branches or update --check to
force update)
# exit code 0

How do I fix this?  I haven't found instructions on the various OpenJDK
sites.

Pete