users-admin doing lots of (apparently needless) work

[Gavin McCullagh]

Hi,

when you add/edit an account with users-admin, /var/log/auth.log shows a
large number of entries indicating that all users gid,shell,password all
get reset even when they are unchanged.

Sep 25 16:35:23 edubuntu usermod[20376]: change user `root' GID from `0' to `0'          
Sep 25 16:35:23 edubuntu usermod[20376]: change user `root' shell from `/bin/bash' to `/bin/bash'                                                                                 
Sep 25 16:35:23 edubuntu usermod[20376]: change user `root' password  
Sep 25 16:35:24 edubuntu usermod[20378]: change user `daemon' GID from `1' to `1'                     
Sep 25 16:35:24 edubuntu usermod[20378]: change user `daemon' shell from `/bin/sh' to `/bin/sh'                                                                   
Sep 25 16:35:24 edubuntu usermod[20378]: change user `daemon' password 
..... etc.

I have in the past noticed that having added a new account, users-admin
could be rather slow to close.  I've just run the program on my home
(debian etch) machine and tailed auth.log as I wait for it to close.  The
delay corresponds to the time taken for the above entries to be generated.

We currently have about 20 users on our edubuntu server.  I am a little
concerned that as we add more and more users, this program is going to get
increasingly sluggish -- scaling linearly as it does.  This behaviour seems
unnecessary, as though the program is not aware of what the user has
changed, so it just rewrites everything.

Does anyone know this code well enough to say whether this can easily be
made more efficient?

Gavin