cannot sync - pulling is not possible because you have unmerged files

[db]

I cannot synchronize the ports tree. Four days ago I installed master from same day, October 16th. I now get this error

$ sudo port -v sync
--->  Updating the ports tree
Synchronizing local ports tree from file:///opt/local/myports
Creating port index in /opt/local/myports

Total number of ports parsed:	0 
Ports successfully parsed:	0 
Ports failed:			0 
Up-to-date ports skipped:	69

Synchronizing local ports tree from file:///opt/local/var/macports/sources/github.com/macports/macports-ports/
error: Pulling is not possible because you have unmerged files.
hint: Fix them up in the work tree, and then use 'git add/rm <file>'
hint: as appropriate to mark resolution and make a commit.
fatal: Exiting because of an unresolved conflict.
Command failed: /opt/local/bin/git pull --rebase --autostash
Exit code: 128
Syncing local Git ports tree failed
port sync failed: Synchronization of 1 source failed