Merge in Mercurial

>hg push (fail due to different heads, merge is required)

pushing to http://joel.example.com:8000/
searching for changes
abort: push creates new remote heads!
(did you forget to merge? use push -f to force)

>hg pull
>hg merge (manually merge is sometimes required to solve the conflict)
>hg com -m "merge"
>hg push

Reference: 
http://hginit.com/top/04.html