user-mail-address possibly set too early

[David]

I have found that I cannot set user-mail-address by setting mail-host-address
in my .emacs file.

I modified startup.el like this:

        ;; Also re-set the language environment in case it was
        ;; originally done before unibyte was set and is sensitive to
        ;; unibyte (display table, terminal coding system &c).
        (set-language-environment current-language-environment)))
(message  (format  "in startup 1 mail-host-address %s"      mail-host-address))
(message  (format  "in startup 1 user-mail-address %s"      user-mail-address))
    ;; Do this here in case the init file sets mail-host-address.
    (or user-mail-address
        (setq user-mail-address (concat (user-login-name) "@"
                                        (or mail-host-address
                                            (system-name)))))
(message  (format  "in startup 2 mail-host-address %s"      mail-host-address))
(message  (format  "in startup 2 user-mail-address %s"      user-mail-address))

Which results in the following *Messages*.  On the face of it, it appears that
user-mail-address is set before my init file is loaded.

This is my shell command.  File .data-emacs-A loads my .emacs.
/home/Downloads/emacs-21.3/src/emacs -q -l /home/dajo/.data-emacs-A &

The various messages in *Messages* about loading, etc., come from
.data-emacs-A and .emacs.  After loading, user-mail-address has value
dajo@aussie.uchsc.edu.  I can set successfully user-mail-address to another
value in my .emacs.

*Messages*:
tooltip...done
in startup 1 mail-host-address nil
in startup 1 user-mail-address nil
in startup 2 mail-host-address nil
in startup 2 user-mail-address dajo@aussie.uchsc.edu
For information about the GNU Project and its goals, type C-h C-p.
.data-emacs-A commencing loading in GNU Emacs 21.3.1 (i686-pc-linux-gnu, X 
toolkit)
 of 2004-04-27 on aussie.uchsc.edu.
default-frame-alist is  ((tool-bar-lines . 1) (menu-bar-lines . 1) (width . 80) 
(height . 25))
initial-frame-alist is  nil
selected-frame is  #<frame emacs@aussie.uchsc.edu 0x84ea7b8\ >
data-emacs-A nil
data-emacs-A dajo@aussie.uchsc.edu
Loading /home/dajo/.emacs...
.emacs commencing loading in GNU Emacs 21.3.1 (i686-pc-linux-gnu, X toolkit)
 of 2004-04-27 on aussie.uchsc.edu.
default-frame-alist is  ((tool-bar-lines . 1) (menu-bar-lines . 1) (width . 80) 
(height . 25))
..
<snip>
..
Loading mailalias...done
.emacs completed loading.
..
<snip>
..
.data-emacs-A completed loading.