[We need to define a policy about whether it is OK to rename accounts. Since accounts can be removed and then recreated under a different user name, I guess it is OK. Something like a redirection, or a way for Savane to say "this user Y was called X previously between 2005-01-01 and 2006-02-03"]

Check infra/maintenance/rename_user.sh

We could also change the projects CVS files to change the user name associated with each change. Is there a cvs command to do that and is it pertinent?

Karl writes in this recent discussion (http://lists.gnu.org/archive/html/savannah-hackers/2016-05/msg00043.html):

There are four mysql commands listed in rename_user.sh (that is, mgt0:/opt/administration/maintenance/rename_user.sh).

Just run them by hand on mgt0, don't try to run the script; the whole vserver setup as used in that script is from a past incarnation.

Note that if a user doesn't belong to any groups and never previously belonged to any groups then there might not have been any previous group_history to modify. And also in that case there won't be any account created yet for them since accounts are created when they first become a member of any project.