Received this error while trying to deploy Wikimetrics with fabric:
Fatal error: sudo() received nonzero return code 128 while executing!
Requested: git fetch origin master
Executed: sudo -S -p 'sudo password:' -u "wikimetrics" /bin/bash -c "export HOME=\"/srv/wikimetrics\" && cd /srv/wikimetrics/src >/dev/null && git fetch origin master"
WORKAROUND: go to the server, git pull manually, and then deploy again.
Looks like some permission problem, but I don't really have time to figure this out since I'm trying to fix a more serious production bug.