Switch cat command to use walk code.
The old syntax of "hg cat FILE REV" is now obsolete.
Use "hg cat -r REV FILE" instead, as for all other commands.
pushing to ../a
searching for changes
abort: unsynced remote changes!
(did you forget to sync? use push -f to force)
pulling from ../a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
(run 'hg update' to get a working copy)
pushing to ../a
searching for changes
abort: push creates new remote branches!
(did you forget to merge? use push -f to force)
pushing to ../a
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 1 changes to 1 files