[Bese-devel] what's wrong with the following code?

[Friedrich Dominicus]

(defaction shop-login ((login shop-login) username password)
  (setf (login.username login) username
        (login.password login) password)
  (let* ((user-data (check-credentials login))
         (shipping-adr (make-instance 'shipping-adr :adr (car (qss.db::shipping-address user-data)))))
        ;; car is needed because a join slot always returns a list!     
    (inspect login)
    (inspect shipping-adr)
  (if shipping-adr
      (call 'customer-input-page
            :customer-data user-data
            :address shipping-adr
            :payment-details nil)
      (call 'info-message 
            :message "Login failed"))))

The shipping-adr class is defined this way:
(defcomponent address-mixin ()
  ((adr :initarg :adr :accessor adr
        :backtrack t
        :initform (make-instance 'qss.db::shipping-address)))
  (:metaclass standard-component-class))

;; (forget-class :shipping-adr)
(defclass shipping-adr (address-mixin)
  ()
  (:metaclass standard-component-class))

If I inspect login I see the following:
0. CONTINUATION: (IT.BESE.ARNESI::TOPLEVEL-K)
1. CALLING-COMPONENT: #<TRANS-INFO {1001F24851}>
2. PLACE: #<IT.BESE.UCW::PLACE (CONTEXT.WINDOW-COMPONENT
                                *CONTEXT*) {1001391471}>

that's ok, the shipping-adr has the following
0. CONTINUATION: "unbound"
1. CALLING-COMPONENT: "unbound"
2. PLACE: "unbound"

which seems itself reasonable, but then I do the following
(defmethod render-on ((res response) (customer-page customer-input-page))
  (<:h1 "Your adress data: ")
  (render-on res (address customer-page)))

which then calls this:
(defmethod render-on ((res response) (adr shipping-adr))
  (let ((address (adr adr)))
    (inspect adr)
    (<ucw:form :action (edit-address adr)
               (<:table 
                (dolist (item '(street zip city country email))
                  (present-a-slot-as-table-row item (slot-value address item))))
               (<:p
                (<ucw:submit :action (edit-address adr)
                             :value "Edit")))))

This is rendered fine.

But then I push the button and got:
The slot IT.BESE.UCW::PLACE is unbound in the object #<SHIPPING-ADR {10017C2171}>.
   [Condition of type UNBOUND-SLOT]

Restarts:
  0: [SHOW-BACKTRACE] Send the client a backtrace page.
  1: [RETRY] Clearout the response and retry calling the action.
  2: [SERVER-ERROR] Send the client an internal server error page.
  3: [GENERATE-BACKTRACE-FOR-EMACS] Generate a bug report in Emacs.
  

That's of course true, but not what I like to see of course I'd like
to call the next action and go on from there. 

So how am I supposed to build such a action-render-render-action 
chain?

what i want is:
checking the login credentials
if the the customer can be found then show me his/her address
if the data have changed allow to change them 
change the data 
display the changed data
go on wiht the state as if he/she had not changed the address
display e.g the payment terms the customer has taken.
allow changes as needed 
etc.

Help would be very appreciated.

Regards
Friedrich