On Fri, 15 Apr 2011 16:52:45 -0300 Stefan Monnier <monnier@iro.umontreal.ca> wrote: 

>> Maybe it's better to use this new `nnimap-user' backend variable
>> directly.  IOW, if it's set, it should override anything from
>> auth-source, and the auth-source search should not use `nnimap-user',
>> just the host and the ports.  WDYT?

SM> Doesn't sound right: what if you have several accounts on the same
SM> IMAP server?  auto-info needs to know the username in order to find the
SM> right password.

In Gnus, you'd set up multiple secondary servers with the same machine
address and each one has its own nnimap-user.  Then `auth-source-search'
is passed the server name and the machine name, and will use the server
name first.  IOW:

Gnus: server1 = (machine.domain.com, nnimap-user "user1")
      server2 = (machine.domain.com, nnimap-user "user2")

.netrc/.authinfo{,.gpg}: 
machine server1 password password1
machine server2 password password2

But what bugged you is the auth-source prompting for the user name,
right?  See the attached patch, it will also set
`auth-source-creation-defaults' if `nnimap-user' is set, so you won't be
asked for the user name every time a virtual auth-source entry is
created.  You should only be asked for the password and whether you want
to save the entry (as per `auth-source-save-behavior').

Ted