bug#14785: 24.3.50; isearchb.el; char-to-string and last-command-event

[Juri Linkov <juri@jurta.org>]

After loading isearchb.el, evaluating (isearchb-set-keybindings 'super)
and typing `s-a', it fails with the error

  Wrong type argument: characterp, 8388721

This patch seems to fix the bug:

=== modified file 'lisp/isearchb.el'
--- lisp/isearchb.el	2013-01-01 09:11:05 +0000
+++ lisp/isearchb.el	2013-07-03 23:36:20 +0000
@@ -139,7 +139,8 @@ (defun isearchb ()
   (if last-command-event
       (setq iswitchb-rescan t
 	    iswitchb-text (concat iswitchb-text
-				  (char-to-string last-command-event))))
+				  (char-to-string
+				   (event-basic-type last-command-event)))))
   (iswitchb-set-matches)
   (let* ((match (car iswitchb-matches))
 	 (buf (and match (get-buffer match))))


PS: I wonder whether other similar places should be fixed too?
Grepping for `char-to-string' and `last-command-event':

./calc/calc-aent.el:282:     (calc-alg-entry (and auto (char-to-string last-command-event))))))
./calc/calc-aent.el:457:	 (t (char-to-string last-command-event)))))
./calc/calc-misc.el:591:  (if (keymapp (key-binding (char-to-string last-command-event)))
./calc/calc.el:2438:      (insert (char-to-string last-command-event))
./emulation/vi.el:987:      (setq this-command (lookup-key vi-com-map (char-to-string last-command-event)))
./emulation/vi.el:992:	(setq this-command (lookup-key vi-com-map (char-to-string last-command-event))))
./eshell/esh-mode.el:477:   (char-to-string (if (symbolp last-command-event)
./international/quail.el:1599:	(concat quail-current-key (char-to-string last-command-event)))
./wdired.el:771:      (let ((new-bit (char-to-string last-command-event))

Maybe they don't fail when `last-command-event' is expected to be only
a character event.  But I don't know how to test most of these functions
to verify whether they fail or not.