As a preloaded file, isearch.el cannot require cl-lib at runtime.
(setq isearch-pre-move-point (point)))
;; Append control characters to the search string
((eq search-exit-option 'append)
- (when (cl-every #'characterp key)
+ (unless (memq nil (mapcar (lambda (k) (characterp k)) key))
(isearch-process-search-string key key))
(setq this-command 'ignore))
;; Other characters terminate the search and are then executed normally.