bug#8266: :complete-function in define-widget does not work as it used to

[Lennart Borgman]

I have used constructs like this many times, but now the
:complete-function does not work any more. It gives me "idx" (which I
expect) but insert it in the wrong place.

To show it evaluate the code below and do "M-x customize-option RET
idxsearch-engine RET" and try to complete the choice.


(defvar idxsearch-engines
  '((idxdocidxer-search "DocIndexer")
    (idxgds-search "Google Desktop Search")
    (idxwds-search "Windows Desktop Search"))
  "Search engines.")

(defun idxsearch-funp (fun)
  (assoc fun idxsearch-engines))

(define-widget 'idxsearch-function 'function
  "A index search function known by `idxsearch."
  :complete-function (lambda ()
                       (interactive)
                       (lisp-complete-symbol 'idxsearch-funp))
  :prompt-match 'idxsearch-funp
  :prompt-history 'widget-function-prompt-value-history
  :match-alternatives '(idxsearch-funp)
  :validate (lambda (widget)
              (unless (idxsearch-funp (widget-value widget))
                (widget-put widget :error (format "Unknown index
search function: %S"
                                                  (widget-value widget)))
                widget))
  :value 'fundamental-mode
  :tag "Index search specific function")

(defcustom idxsearch-engine (cond
                             ((idxgds-query-url-p) 'idxgds-search)
                             (t (if (eq system-type 'windows-nt)
                                    'idxwds-search
                                  'idxdocidxer-search)))
  "Desktop search engine for `idxsearch' to use."
  :type 'idxsearch-function
  :group 'idxsearch)